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1.2 Supplement to Application
RS Diiv Washington DMsion CHEVRON PICEANCE BASIN NATURAL GAS DEVELOPMENT PROGRAM STORM -WATER MANAGEMENT PLAN CONSTRUCTION STORM -WATER FIELD PERMIT F Incorporation of site specific information CG EB 06/08 E Incorporations of Washington Group International Revisions KR / RC 08/07 B C D Cordilleran Revisions -- 6/06; 10/06; 08/07 A Initial Plan — prepared by Cordilleran Compliance Services, Inc.EM 09/05 REV. DESCRIPTION BY CHKD APUD RVWD DATE REVISIONS CLIENT: Chevron North America Exploration and Production Company PROJECT: Piceance Basin Natural Gas Development Program — Early Production System PROJECT NO.: 29454 — Under Chevron Contract Number C537211 DOC. NO.: PBSR-ALL-RGL-PMT-URS-00000-00002-00 Acknowledgement of input from the following organizations: CORDILLERAN Washington Group International Integrated Engineering, Construction, and Management Solutions Table of Contents 1.0 Introduction / Purpose 1 1.1. Regulatory Requirements 1 1.2. Project Location and Description 2 1.3. Project Owner and Operator 2 2.0 Construction Site Characteristics 4 2.1. Physiography, Relief, and Drainage 4 2.2. Soil Types / Characteristics 5 2.2.1. Drainage Area Soils 6 2.2.2. Side Slope Soils 6 2.2.3. Plateau Soils 6 2.3. Vegetative Communities 7 2.4. Regional Climate 7 2.5. Regional Surface Water Classifications 7 3.0 Construction Activities 9 3.1. Well Pad Development Activities 9 3.1.1. Well Pad Development 9 3.1.2. Pipeline Development 10 3.1.3. Road Development 10 3.1.4. Facilities Development 13 4.0 Reclamation During Production Activities 15 4.1. Well Pads Production Activities and Reclamation 15 4.2. Pipeline Completion and Reclamation 16 4.3. Road Completion and Reclamation 16 4.4. Facilities Production Activities and Reclamation 16 5.0 Final Reclamation 18 5.1. Well Pads - Final Reclamation 18 5.2. Pipeline - Final Reclamation 18 5.3. Roads - Final Reclamation 18 5.4. Facilities - Final Reclamation 19 6.0 Potential Pollution Sources 20 7.0 Control Measures — General Descriptions 21 7.1. Soil Erosion and Sediment Controls 21 7.1.1. Sediment Control Berms 21 7.1.2. Check Dams 21 7.1.3. Culverts 21 7.1.4. Culvert Inlet and Outlet Protection 22 7.1.5. Diversions 22 7.1.6. Drainage Dips 22 7.1.7. Erosion Control Blankets and Mats 22 7.1.8. Filter Berms 22 7.1.9. Georidge 22 7.1.10. Gravel Surfacing 23 7.1.11. Land Grading 23 7.1.12. Level Spreader 23 7.1.13. Mulching 23 7.1.14. Retaining Walls 23 7.1.15. Re -vegetation 23 Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company i Piceance Basin Natural Gas Development Program 7.1.16. Riprap 23 7.1.17. Roadside Ditches and Turnouts 24 7.1.18. Sediment Traps 24 7.1.19. Silt Fence 24 7.1.20. Slope Drains 24 7.1.21. Stabilized Construction Entrance 24 7.1.22. Straw Bale Barriers 24 7.1.23. Erosion/Sediment Control Log/Wattles 25 7.1.24. Surface Roughening 25 7.1.25. Terracing 25 7.1.26. Vegetative and Grass Buffer 25 7.1.27. Waterbars 25 7.1.28. Diversion Ditch/Berms 25 7.1.29. Slope Stabilization 25 7.1.30. Concrete Washout Facilities 26 7.1.31. Sanitary/Septic (Port -O -Let) Waste Management 26 7.1.32. Inlet Protection 26 7.2. Sources of Additional BMPs 26 7.3. Management of Storm -Water Controls 27 7.4. Other Controls 27 7.4.1. Fuels and Materials Management 27 7.4.2. Other Chemicals Products Management 28 7.4.3. Materials Management 28 7.5. Construction Site Housekeeping 29 8.0 Inspection and Maintenance Procedures 30 9.0 Non -Storm -Water Discharges 32 10.0 Final Stabilization 33 11.0 Owner/Applicant Certification 34 Attachments Construction Storm -Water Permit COR -037787 Figures Tables URS Specification for the Re -vegetation of Disturbed Areas Typical Storm -Water Best Management Practices (BMPs) Details Down -Hole Chemical List Storm -Water Field Inspection Report Form Site Specific Plans / Drawings Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company ii Piceance Basin Natural Gas Development Program 1.0 INTRODUCTION / PURPOSE The following Storm -Water Management Plan (SWMP) was prepared to comply with the Colorado Department of Public Health and the Environment's (CDPHE) General Permit No. COR -030000 issued on July 1, 2007 and expiring on June 30, 2012, and related U.S. Environmental Protection Agency (USEPA) National Pollutant Discharge Elimination System (NPDES) storm -water regulations. Chevron's permit renewal approval is provided as an attachment to this plan (Construction Storm -Water Permit COR -037787). Construction permits are required for oil and gas activities that disturb one or more acres during the life of the project or are part of a larger common plan of development. CDPHE added another option for permits in its Stormwater Fact Sheet—Construction at Oil and Gas Facilities (revised in July 2007), the Field Permit certification. As detailed in the fact sheet, CDPHE recommended that oil and gas developments be covered under a Field Permit certification. The Field Permit covers all construction activities and discharges to waters of the State of Coloradolisted in the complete project permit. Chevron North America Exploration and Production Company (Chevron) has amended its original permit renewal application on August 15, 2007 to be covered under a Field Permit rather than a common plan of development, as originally submitted. The purpose of the Master SWMP is to provide information, procedures, and best management practices (BMPs) for all construction and operation activities associated with development of the natural gas resources in the Skinner Ridge Field, known as the Chevron Piceance Basin Natural Gas Development Program (Program). The SWMP will be updated as necessary to address storm -water management and surface -water quality protection for planned developments, new disturbances, and other changes. Site-specific SWMPs, based on controls and procedures summarized in the Master SWMP, will be prepared for each facility / construction activity and provided as appendices to this plan. 1.1. Regulatory Requirements The Federal Clean Water Act [Section 402(p)] requires that discharges of pollutants to waters of the United States from any point source be regulated by NPDES permits. In November 1990 the USEPA published final regulations establishing application requirements for storm -water discharges associated with construction activities involving soil disturbances of five acres or more and requiring these disturbances to be regulated as industrial activities covered by an NPDES permit. In December 1999 the USEPA published final Phase II NPDES storm -water regulations establishing application requirements for storm -water discharges associated with construction activities for soil disturbances regulated as industrial activities and covered by an NPDES permit. These regulations became effective July 1, 2002. On June 30, 2005, the State of Colorado storm -water regulations came into effect and required Colorado Discharge Permit System (CDPS) permits from the Water Quality Control Division (the Division) for storm -water discharges resulting from small construction sites (those disturbing between one and five acres), including oil and gas sites. CDPS requirements for oil and gas construction sites disturbing five or more acres during the life of the project, or that are part of a larger common plan of development, have been in effect since 1992. Although federal permit coverage for these discharges was conditionally exempted from the Federal Clean Water Act by the 2005 Federal Energy Bill, the Colorado Water Quality Control Commission (WQCC) has maintained the requirement within Colorado's regulations. CDPS requirements are in addition to the Colorado Oil and Gas Conservation Commission (COGCC) erosion control regulations. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 1 Piceance Basin Natural Gas Development Program 1.2. Project Location and Description The Program is located in Garfield County, Colorado within Townships 5, 6, 7, 8 and 9 South, Ranges 97 and 98 West (Figure 1). The town of De Beque, Colorado, the nearest population center, is located about 14 miles south of the Skinner Ridge Field. Chevron is developing about 33,000 acres in the Piceance basin. The Program anticipates drilling about 2,800 wells over a 14 year period. Design life of the field is projected at 30 years. Field gathering lines collect production fluids from the well pads and transport the full well stream (FWS) to the Production Cluster Pads (PCP) for initial natural gas separation. Discharge lines from the joint trunk lines flow to a Central Production Facility (CPF) (multiple production facilities will be required for the Program). At the production facilities, the natural gas and liquids are further separated. The natural gas is compressed, dehydrated and sent to a sales point through a recently constructed 30 -inch export gas pipeline. Hydrocarbon condensate will be stabilized and stored in holding tanks for transport to processing facilities via tanker truck. A percentage of the produced water will be used for hydraulic fracturing operations. The remaining produced water will be pumped to a water treatment facility where salts and any remaining hydrocarbons will be removed. The treated water will be used for drilling operations and potentially as a potable water supply. Brine and solids are anticipated waste streams from this process. Current plans are to use permitted disposal injection wells for the brine and to transport the solids to a permitted waste disposal facility. The current drilling and development plan includes well pad construction, well drilling, completion and testing, access road improvement/construction, support facility construction (production facilities, offices, water treatment facilities, etc.), utility installation, and pipeline construction. The area of estimated disturbance, including the natural gas well pads, access roads, and gathering system pipeline, will exceed 370 acres. Disturbance beyond five years will require re-evaluation. Figure 2 shows some of the well pads and facilities associated with the early phases of the Program. 1.3. Project Owner and Operator The property owner and operator is Chevron U.S.A. Inc. The local field address is: Chevron U.S.A. Inc. 760 Horizon Drive Grand Junction, CO 81506 The Chevron contact person for the project is: Michael DeBerry Manager, Piceance Basin Operations 744 Horizon Court, Suite 140 Grand Junction, CO 81506 Office: 970-257-6005. Cell: 307-679-4050 The SWMP Administrator is: Richard Carroll Environmental Specialist, Piceance Basin Operations Chevron MCA Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 2 Piceance Basin Natural Gas Development Program Office: 970-257-6026 Chevron is in charge of all aspects of this project. Contractor(s) will be employed for construction, drilling, and construction management, but all work is supervised by Chevron and all decisions are made by Chevron. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 3 Piceance Basin Natural Gas Development Program 2.0 CONSTRUCTION SITE CHARACTERISTICS The following information is provided for engineering and planning purposes to assist with facility placement and selection of stabilization techniques and erosion controls. 2.1. Physiography, Relief, and Drainage According to the Natural Resource Conservation Service (NRCS) Sail Survey Map of the Douglas Plateau Area, Colorado, Parts of Garfield and Mesa Counties, the subject area is located within the Piceance Basin on the eastern fringe of the Colorado Plateau. It includes the Roan Plateau, Bookcliffs, and is adjacent to portions of the Grand Mesa and Grand Valley areas. It consists of deeply incised valleys, entrenched plateaus, and foothills. The broader portion of the valley is carved out by the Colorado River and its tributaries. The development site elevation ranges from a valley floor elevation of 5,800 feet to a height of 8,500 feet at the Roan Plateau. The Roan Plateau extends north into Rio Blanco County, and surrounds the Skinner Ridge property. The shallowest stratigraphic unit in the Piceance Basin is the Uinta Formation, which consists of discontinuous layers of silty sandstone, siltstone and marlstone deposits. The Uinta Formation overlies the Green River Formation, which contains vast deposits of oil shale. The Wasatch, Lower Fort Union and Mesaverde Formations underlie the Green River Formation, and consist of sandstones, mudstones, and coal. These formations represent the major gas producing formations of the Piceance Basin. The natural gas occurs as non -conventional gas at the Skinner Ridge development site. Surface and groundwater features are located within the upper reaches of the Clear and Roan Creeks, where the Program area lies. These features consist of ephemeral streams fed by seasonal rainfall and snowmelt. Springs and seeps are also observed throughout the area. One seep in particular, was harnessed with a cistem and used for habitation of a historical site near the confluence of Tom Creek and Clear Creek. Most of the geological material underlying the Skinner Ridge property is impervious to water. Except for the alluvium within the major streambeds, there is no known extensive aquifer. Developed Spring at the Confluence of Tom and Clear Creeks Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 4 Piceance Basin Natural Gas Development Program The alluvial aquifer consists of narrow and relatively thin sand and gravel deposits adjacent to and beneath Clear Creek. In the northern portion of the development site, the alluvial aquifer is underlain by the confining unit below the Lower Piceance Basin aquifer (Douglas Creek Member of the Green River Formation), which consists of fine-grained sandstone, limestone and shale. And, in the southern portion of the site, the alluvial aquifer is underlain by the Wasatch Formation, which consists of sandstone and shale. The Roan Plateau is underlain by the Upper Piceance Basin aquifer (Uinta Formation), which consists of silty sandstone and fractured siltstone. The hydraulic gradient in the bedrock aquifers underlying the Roan Plateau is predominately vertical and downward. However, along the margins of the plateau there are strong horizontal hydraulic gradients flowing toward the cliff faces and valley slopes. Because of these strong horizontal gradients, ground water is discharged from the bedrock aquifers as springs even though the bedrock aquifers dip away from valley slopes. Numerous seeps and springs are present along the valley slopes above Clear Creek and a large seep is present on the valley slope above Tom Creek. 2.2. Soil Types / Characteristics Detailed soil information was collected as part of Chevron's internal Environmental, Social and Health Impact Assessment (ESHIA) (ERM, 2008). Three main groups of soils (of 26 delineated soil types) are present within the Program area: (1) drainage area soils, (2) side slope soils, and (3) plateau soils (also referred to as mesas). Drainage soils occur on benches, terraces, alluvial fans, and floodplains in the valleys of Roan Creek, Clear Creek, and their tributaries. These soils are deep, well to somewhat poorly drained, and nearly level to gently sloping, with water erosion hazard ranges from slight to severe. Drainage soils include soils that are classified as prime farmland. Side slope soils of Skinner Ridge, Puddin Ridge, and other slopes along the plateau and other mountain slopes, are dominated by shallow, poorly developed soils and rock outcrops. These soils have a severe erosion potential and some have very steep slopes that limit their potential for construction and re -vegetation. Plateaus / mesa top soils are mostly well -drained, cool soils, with dark -colored, organic -rich surface layers. These soils have a slight to severe erosion potential. Table 1 (see Tables attachment) provides a summary of the characteristics of the 26 identified soil types and their susceptibility to erosion. Table 2 (see Tables attachment) provides additional details of the individual soil types including soil textures, profile, vegetative types, slope, and erodability. Figure 3 provides a graphical representation of the locations of the prominent soils (Ref: Figure 4-14 ESHIA report) (see Figures attachment). Erosion susceptibility is presented graphically as Figure 4 (Ref: Figure 16-1 ESHIA report) (see Figures attachment). For preliminary site erosion control requirements, Tables 1 and 2 should be used in combination with Figures 3 and 4 to determine soil types and characteristics present at a proposed facility location. For instance, in the area of Central Production Facility, Cumulic Haploborolls are present at 1 to 3 percent slopes, with well to poorly drained soils found in riparian zones. Site specific soil / vegetation information was extracted from the following reference: Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 5 Piceance Basin Natural Gas Development Program Soil Survey of Douglas -Plateau Area, Colorado, Parts of Garfield and Mesa Counties, United States Department of Agriculture, Natural Resources Conservation Service, 2003 (available at http://cals.arizona.edu/OALS/soils/surveys/co/co.html). 2.2.1. Drainage Area Soils These soils formed from alluvial material derived from sandstone and shale, and occur on benches, terraces, alluvial fans and floodplains in the valleys of the Roan, Willow, Brush and Clear Creeks, and other unnamed tributaries. These soils are deep, well drained to somewhat poorly drained, and nearly level to gently sloping. Surface textures range from loam and sandy loam to clay. The soils are calcareous, moderately to strongly alkaline, and some are highly saline. Permeability ranges from very slow to moderately rapid, and water erosion hazard ranges from slight to severe. The soils found along the drainages include soils that are classified as prime farmland (Cumulic Haploborolls, Dominguez, and Panitchen) and hydric soils (Fluvaquents). 2.2.2. Side Slope Soils The soils formed along the side slopes of Skinner Ridge, Brush and Kimball mountains, and other mountains ranges in the Piceance Basin, are dominated by shallow, poorly developed soils and rock outcrops (e.g., Torriorthent-Rock Outcrop and Utso-Rock Outcrop map units). Below the cliffs and talus is a zone of soils formed from colluvial material. This zone includes rock outcrops, badlands, moderately sloping valleys, and fans draining into Roan Creek. These soils have a severe erosion potential and some have very steep slopes that limit their potential for construction. Typical Program Area Cliffs / Side Slopes The badlands are steep, nearly barren and dissected by numerous ephemeral drainages. Soils on the upper slopes have a thin organic -rich surface layer and exhibit little soil development. Soils on the lower slopes range from shallow to moderately deep and are well drained. Side slope grades are presented graphically in Figure 5 (Ref: Figure 16-2 ESHIA report) (see Figures attachment). 2.2.3. Plateau Soils These soils formed in material weathered from the Green River Formation shale and Uinta Formation sandstone, and are mostly well -drained, cool soils, with dark -colored, organic -rich surface layers. The surface textures are generally loam, with loam to clay loam subsoils and channery profiles (sandstone and shale fragments). Soil thickness ranges from deep (>60 inches) Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 6 Piceance Basin Natural Gas Development Program in swales to shallow (<20 inches) on ridge tops. These soils have a moderate permeability and a slight to severe erosion potential. 2.3. Vegetative Communities The eleven vegetation communities that were found in the Program area are listed below and shown as Figure 6 (see Maps & Figures). The vegetation communities in the Program area reflect the wide ranges of elevation, topography, aspect, and moisture. Aspen forests, deciduous oak shrublands, Douglas fir forests, mesic upland shrub communities, and mountain sagebrush shrublands are common in the higher elevations of the Program area. Big sagebrush shrublands, riparian areas, and irrigated cropland are present in the deep valleys. Juniper woodland forests, greasewood flats, and desert shrub communities are common on the exposed steep slopes, in dryer areas, and on shale plateaus. Vegetation communities have developed across the landscape in response to climate, disturbance, and other environmental factors. Vegetation Community Type Percent of Study Area Aspen forest 4.0 Big sagebrush 2.6 Desert shrub 1.2 Douglas fir forest land 6.2 Exposed rock 1.0 Forest -dominated riparian 1.1 Greasewood fans and flats 1.3 Irrigated cropland 7.6 Juniper woodland forest land 5.2 Mesic upland shrub 22.2 Mountain sagebrush 46.7 Additional information about vegetative communities associated with the various soil types is presented in Table 2. Identification of the vegetative community to be disturbed is very important to initial site selection and/or re -vegetation planning, because some types are more sensitive to disturbance, while others are far more resilient. 2.4. Regional Climate Climate information was collected as part of the ESHIA study. The ESHIA report describes the general climate of the study area as influenced by dry air, sunny days, clear nights, variable precipitation, with moderate evaporation and large diurnal temperature changes. These are generally due to changes in topography between the valleys and mesas. Annual precipitation ranges from about 10 to 20 inches. Seasonal and daily temperatures vary with elevation and, to a lesser extent, local microclimates. Daily temperatures, in degrees Fahrenheit, in the summer usually range from the upper 40s to the lower 80s in mountain terrains, and mid 90s in the western valleys. In the winter, cold air commonly accumulates in the valleys. Prevailing winds in the upper levels of the atmosphere are mostly from the southwest, but local air movements are strongly influenced by topography including elevated mesas, steep slopes, narrow canyons and rough terrain in the Study Area. 2.5. Regional Surface Water Classifications The initial Program area lies in the Roan Creek watershed, which includes Clear Creek and its tributaries, with future development in the Parachute Creek watershed. Under the Colorado Water Quality Control Commission, Regulation 37, Regulations for the Lower Colorado Basin, these are named Segments 14a and 14b of the Lower Colorado River Basin and Sub -basin. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 7 Piceance Basin Natural Gas Development Program Segment 14a includes the mainstem of Roan Creek including all wetlands and tributaries, from the source to a point immediately above the confluence with Clear Creek (except for a listing in Segment 14b); Clear Creek, including all tributaries and wetlands, from the source to a point immediately below the confluence of Tom Creek. Segment 14b consists of Clear Creek, including all tributaries and wetlands, from a point immediately below the confluence with Tom Creek to the confluence with Roan Creek; Roan Creek, including all tributaries and wetlands, from a point immediately above the confluence with Clear Creek to a point immediately below the confluence with Kimball Creek. Segment 14a is designated as reviewable and its classified beneficial uses are: aquatic life class one cold, recreation P (primary contact), water supply, and agriculture (irrigation and cattle grazing). At a recent rulemaking hearing (June 2008), the Division indicated that this segment warranted a cold temperature standard tier I, due to the presence of brook and cutthroat trout. This is indicative of a sensitive habitat that should utilize greater protection when considering disturbance and proper selection of stabilization and erosion controls [typically referred to as Best Management Practices (BMPs)]. Segment 14b has the same designation and classified use; however, it has a cold temperature standard tier II, for the presence of rainbow and brown trout, mottled sculpin, mountain whitefish, longnose sucker, and Arctic grayling. Again these designations are indicative of a sensitive habitat warranting greater protection when considering disturbance and proper selection of BMPs. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 8 Piceance Basin Natural Gas Development Program 3.0 CONSTRUCTION ACTIVITIES As mentioned in Section 1.2 the development of the Program will involve multiple construction activities including well pad construction, well drilling, completion and testing, access road improvement/construction, support facility construction (production facilities, offices, water treatment facilities, etc.), utility installation, and pipeline construction. The following sections provide general descriptions of these activities and the measures that will be used to minimize the Program impacts. 3.1. Well Pad Development Activities The well pad development phase includes the following activities: pad construction, well drilling, well completion, gas line installation, and pad area reclamation. Pad reclamation is accomplished by backfilling the reserve pit, contouring disturbed soils to conform with the surrounding terrain, replacing the stockpiled top soil, seeding of disturbed soil areas in order to re-establish a cover vegetation, and construction of erosion and sediment control structures. The completion of the wells (gas production) generally triggers a one-year time period in which the reclamation phase of work should be completed. The final stabilization seed mixture for locations above and below 7,000 feet is provided in a re -vegetation specification provided as an attachment (URS Specification for the Re -vegetation of Disturbed Areas). 3.1.1. Well Pad Development During the initial stages of the well pad construction, heavy equipment will be used to shape and contour the site and any access roads. Design and construction techniques and other practices are to be employed to minimize surface disturbance and the associated effects of proposed operations and maintain the reclamation potential of the site. A typical well pad will be approximately 200 feet by 400 feet, though dimensions may vary due topography and production. Because of the location of the project, steep slopes are expected to be encountered at many of the projected well pad sites. Many of the sites will require vertical cuts and steep fill slopes. Steps will be taken to avoid or mitigate construction in riparian areas and other areas deemed as areas subject to severe erosion. The well site should also be reviewed to determine its effect on the location of the access road. Construction procedures will be implemented that minimize surface disturbance. All topsoil is to be removed from the entire cut and fill area and stored in a designated stockpile for reuse during interim and final reclamation. Topsoil must be segregated and stored separately from subsurface materials to avoid mixing during construction, storage, and interim reclamation. Stockpiles should be properly located and protected to minimize wind and water erosion and maximize available topsoil for reclamation. Excavation of the cut and fill slopes is normally guided by information on the slope stakes. Fills should be compacted to minimize the chance of slope failure. If excess cut material exists after fill areas have been brought to grade, the excess material will be stockpiled at approved locations. The area of the well pad where the drilling rig substructure is located should be level and capable of supporting the rig. The area to be used for mud tanks, mud storage, drilling chemicals, and Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 9 Piceance Basin Natural Gas Development Program fuel tanks should be at a slight slope, where possible, or a suitable alternative such as ditching should be used to provide drainage from the work area to a reserve pit. To reduce erosion and soil loss, it may be appropriate to divert storm water away from well locations with ditches, berms, or waterbars above the cut slopes and to trap well location runoff and sediments on or near the location through use of sediment controls. Sediment controls will dominate this early phase of construction. Temporary BMPs such as silt fences and erosion/sediment control log/wattles will be used in the initial stages to provide perimeter sediment runoff control. As the construction work progresses and the contours of the site are completed, more permanent structural and non-structural BMPs will be implemented. The focus in these later stages willbe on implementing effective erosion controls and in attempting to re -vegetate disturbed areas with native grass seed mix. A summary of the primary Program BMPs is provided in Section 7. Detailed descriptions of BMPs, including where and when the use of individual BMPs is recommended; limitations and where and when they should not be used; construction details and maintenance requirements; and associated photographs and figures are provided in the Typical Storm -Water BMP Details attachment. The attachment includes information on BMPs, including where and when to use them, their limitations, along with construction details and maintenance requirements. Site specific SWMPs for each well pad will be developed as part of the engineering design and provided as an attachment to this plan. 3.1.2. Pipeline Development Steep hillsides and water courses should be avoided when locating pipeline routes. When clearing, the width disturbed should be kept to a minimum. During the excavation phase, designated topsoil stockpiles must be established to the side of the pipeline construction routes. Topsoil material must be segregated and not be mixed or covered with subsurface material. Bladed materials must be placed back into the cleared route upon completion of construction and retumed back to the original contour before reapplying topsoil. Pipeline trenches should be compacted during backfilling. After construction, cut -and -fill slopes must be re -graded to conform to the adjacent terrain and reclaimed. Pipeline right-of-ways must be maintained in order to correct backfill settling and prevent erosion. Appropriate BMPs must be used in sensitive areas to ensure proper site stabilization. Site specific SWMP for each pipeline corridor will be developed as part of the engineering design and provided as an attachment to this plan. Pipeline construction should not block, dam, or change the natural course of any drainage. Suspended pipelines should provide adequate clearance for high-flow events. Pipelines buried across stream crossings should be buried below the scouring depth. Pipelines crossing streams or wetlands will require a U.S. Army Corp of Engineers (USACE) Nationwide or Individual (developed for the entire Program) Permit. This requirement may be avoided by boring under these areas. 3.1.3. Road Development Roads used to access oil and gas locations are rarely permanent and exist only as long as necessary to complete exploration and production operations. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 10 Piceance Basin Natural Gas Development Program Things to consider when constructing a road: • Road width, maximum grade, and crown design. • Location of turnouts. • Plans for soils, hydrology, and topography — dependant drainage, including ditches and locations and sizes of culverts and bridges. • On and off-site erosion control. • Plans for revegetation of disturbed areas. • Fence cuts and cattle guards. • Major cuts and fill. • Source and storage sites for topsoil. • Plans for maintaining roads. All roads must be designed, constructed, and maintained in a safe and environmentally responsible manner. Roads have the potential to cause environmental harm through erosion, air pollution, stream degradation, habitat alteration, and increased public use Careful attention to the proposed road location and design can significantly minimize environmental impacts. When selecting a location for new roads, consider following topographic contours. Following natural contours preserves natural drainage patterns and typically results in lower costs and less impact on the environment. Initial steps in road location include: • Determine the intended use of the road including seasonal use, type of vehicles to be used, and amount of traffic, and safety. • Examine biological, physical, and cultural conditions of the area. • Consider geotechnical factors including soil type, construction / reclamation limits, landslide areas, water problem areas, etc. Basic Design Requirements: • Design for pre -determined speed limit. • Typically width is 25 feet with turnouts In areas where width is less than 16 feet. • Road gradient has major impact on erosion and visual impact. Follow natural terrain as closely as possible. If terrain allows, gradients should not exceed 8 percent except for short distances of 300 feet or less. • Drainage control must be ensured over the entire road through the use of drainage dips, in sloping, natural rolling topography, ditch turnouts, ditches, or culverts. Ditches and culverts may be required in some situations depending on grades, soils, and local hydrology. If culverts or drainage crossings are needed, they should be designed for a 25 year or greater storm frequency. • Gravel may be needed for "soft" road sections, steep grades, highly erosive soils, and clay spoils. • Culverts should be designed for 25 year (one-hour duration) storm frequency with an allowable head that does not overlap the roadway. The minimum size culvert diameter is 18 inches. Construction: • Excavation and fill construction will be performed to secure the greatest practicable degree of roadbed compaction and stability. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 11 Piceance Basin Natural Gas Development Program • Use of excess excavation material, where practical, shall be practiced to improve the road grade or to flatten fill. • Roadbed materials shall be placed parallel to the axis of the roadway in even, continuous horizontal layers. Surface and Drainage Structures: • The proper design and construction of structures for the surface drainage of water from or through the roadway contributes the most to the long-term success of the road and structure, and minimizes maintenance and adverse environmental effects such as sediment erosion and sediment production. It is vitally important to keep water off the road. Surface drainage provides for the interception, collection, and removal of water from the surface of roads and sloped areas. The design may need to allow for debris passage, mud flows, and water heavily laden with silt, sand, and gravel. • The need for drainage structures can be minimized by proper road location. However, properly designed drainage is essential for a stable road. Drainage systems must include the best combination of various design elements, such as ditches, culverts, drainage dips, crown, in -slope or out -slope, low water crossings, subsurface drains, and bridges. • Drainage Structures — Proper location and design can provide economical and efficient drainage. Structural measures are often required to ensure proper and adequate drainage. Some of the most common structures are drainage dips, ditches, road crowning, culverts, bridges, and low water crossings. o Drainage Dips — The primary purpose of a drainage dip is to intercept and remove surface water from the roadway and shoulders before the combination of water volume and velocity begins to erode the surface materials. Spacing of drainage dips depends upon local conditions such as soil material, grade, and topography. o Ditches - The design of ditches must consider the resource objectives for soil, water, maintenance capabilities and associated costs. Ditch grades should be no less than 0.5 percent to allow for positive drainage and avoid sedimentation. o Road Crowning — Crowning provides good drainage of water from the surface of the road. Drainage of the inside ditch and side hill runoff is essential if the road is to be kept dry and passable during wet weather. o Culverts — Culverts are used in two applications: (1) to allow the normal drainage from streams and gullies to flow under the roadway and (2) to drain inside road ditches. All culverts should be laid on natural ground or at the original elevation of any drainage crossed, except as noted below for ditch relief culverts. Culvert diameter design criteria should be a minimum of 18 inches. A hydrological / hydraulic analysis should be performed to determine the amount of water anticipated to flow through the culvert. Analytical factors that must be considered include the delineation of the drainage basin, soil types, drainage area slopes, and at a minimum a 25 -year (one-hour duration) precipitation event. The outlet for all culverts should extend at least one foot beyond the toe of any slope. It may be necessary to install rip -rap or other energy dissipation devices at the outlet end of the culverts to prevent soil erosion and trap sediment. All culverts used in the construction of access roads should be concrete or corrugated metal pipe (made of steel). Properly bedded and backfilled corrugated plastic pipe may be used for secondary drainage but should not be used as part of any roadbed. Evacuation, bedding, and backfilling of culverts should be conducted according to Program specifications. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 12 Piceance Basin Natural Gas Development Program Ditch relief culverts are installed to periodically relieve the ditch line flow by piping water to the opposite side of the road where the flow can be dissipated away from the roadway. The spacing of ditch relief culverts is dependant on the road gradient, soil types, and runoff characteristics. The depth of culvert burial must be sufficient to ensure the culvert is protected for its design life. This requires anticipating the amount of material that may be lost due to road use and erosion. The culvert gradient should be greater than the approach stream or ditch gradient. This improves the flow hydraulics and reduces sedimentation and prevents debris from plugging the culvert inlet. Additional factors to consider for construction activities involving drainage channels: Bridges and Major Culverts: • Construction of some stream crossings may require a USACE Nationwide (404) or Individual Permit. Where a road is open to public travel, applications will be prepared and submitted with sufficient time allowed for any required public comment input periods and approval of the permit by the surface management agency. Wetlands: • Wetlands are especially sensitive areas and should be avoided, if possible. Generally, these areas require crossings that prevent unnatural fluctuations in water level. Under wetland circumstances, culverts should be designed with a flat grade so water can flow either direction and maintain its natural level on both sides. Special attention should be given to selection of culvert materials that will resist corrosion. Low Water Crossings: • Roads may cross small drainages and intermittent streams where culverts and bridges are unnecessary. The crossing can be effectively accomplished by dipping the road down to the bed of the drainage. The construction of gravel, rip -rap, or concrete bottoms may be required. In no case should the drainage be filled so that water will be impounded. Low water crossings that are not surfaced should not be used in wet conditions. Appropriate BMPs must be used in sensitive areas to ensure proper site stabilization. Site specific SWMP for all road construction or improvements will be developed as part of the engineering design and provided as an attachment to this plan. 3.1.4. Facilities Development The category of Facilities is intended to capture all projects constructed in a supporting role to the production facilities previously described. Program facilities will include offices, maintenance facilities, water storage and treatment facilities, compressor stations, man camps, and communication towers. Site specific SWMPs for each facility will be developed as part of the engineering design and provided as an attachment to this plan. During the initial stages of construction, heavy equipment will be used to shape and contour the construction site and any access roads. Design and construction techniques and other practices are to be employed to minimize surface disturbance and the associated effects of proposed operations and maintain the reclamation potential of the site. Steps will be taken to avoid or mitigate construction on steep slopes, riparian areas and other areas deemed as areas subject to severe erosion. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 13 Piceance Basin Natural Gas Development Program Construction procedures will seek to minimize surface disturbance. All topsoil is to be removed from the entire cut and fill area and stored in a designated stockpile for reuse during interim and final reclamation. Topsoil must be segregated and stored separately from subsurface materials to avoid mixing during construction, storage, and interim reclamation. Stockpiles should be properly located and protected so minimize wind and water erosion and maximize available topsoil for reclamation. To reduce erosion and soil loss, it may be appropriate to divert storm water away from facility construction sites with ditches, berms, or waterbars above the cut slopes and to trap facility location runoff and sediments on or near the location through use of sediment controls. Sediment controls will dominate this early phase of construction. Temporary BMPs such as silt fences and erosion/sediment control log/wattles will be used in the initial stages to provide perimeter sediment runoff control. As the construction work progresses and the contours of the site are completed, more permanent structural and non-structural BMPs will be implemented. The focus in these later stages will be on implementing effective erosion controls and attempting to re -vegetate disturbed areas with native grass seed mix. A summary of the primary Program BMPs is provided in Section 7. Detailed descriptions of BMPs, including where and when the use of individual BMPs is recommended; limitations and where and when they should not be used; construction details and maintenance requirements; and associated photographs and figures are provided in the Typical Storm -Water BMP Details attachment. . The attachment includes information on BMPs, including where and when to use them, their limitations, along with construction details and maintenance requirements. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 14 Piceance Basin Natural Gas Development Program 4.0 RECLAMATION DURING PRODUCTION ACTIVITIES The production phase follows the development phase and includes the operation and maintenance activities that will be conducted during natural gas production. The typical equipment on a pad during the production phase consists of a wellhead, a separation unit, from one to several 400 - barrel capacity aboveground tanks for condensate, and an above ground tank for storing produced water. Gas pipelines are also installed during this phase of work. Reclamation activities during this phase include maintenance of re -vegetated areas and maintenance of the erosion and sediment control structures and BMPs that will remain in place following the development phase. Natural gas wells in the Skinner Ridge area are projected to produce for about 20 to 30 years. 4.1. Well Pads Production Activities and Reclamation Once the well pad site is constructed, drilling operations will begin. Depending on the number of wells to be completed and the local conditions encountered, drilling operations at a specific well pad may take six to nine months to complete. Each pad will have reserve pit(s) to handle and contain drilling fluids and cuttings. As part of drilling operations, chemicals used in drilling operations will be stored onsite. A comprehensive list of chemicals that will be used at well pads is provided as an attachment to this plan (Down -Hole Chemical List). Petroleum products also may be present at the well pads, including gasoline, diesel fuel, lubricant oils, hydraulic oils, used oils, and solvents. Ditches will be placed around chemical storage areas to capture and direct any spills to a well cellar. Well pad drainage is designed to flow to the reserve pits in the event of a large spill or release. Drip pans will be utilized if necessary. All wastes will be placed and stored in the proper receptacles prior to removal for off-site disposal. All storage of petroleum products will be in accordance with the Piceance Basin Field Program Spill Prevention Control and Countermeasures (SPCC) Plan. Housekeeping will be maintained in all chemical storage areas. All containers are to remain closed except when adding or removing materials. Where appropriate, materials will be stored in designated buildings / cabinets to prevent their containers from being exposed to precipitation events. Inspection of chemical storage areas will be included as part of the SWMP inspection program The production phase includes the operation and maintenance activities associated with natural gas production. Typical well pad equipment includes a wellhead, a separation unit and one or more 400 barrel (42 gallons per barrel) capacity above ground storage tank(s) containing condensate and or produced water. Secondary containment will be provided around chemical storage areas including condensate tanks and separators. Reclamation activities during this phase include maintenance of re -vegetated areas and maintenance of the erosion and sediment controls structures. Installation, inspection and maintenance of BMPs to control sediment runoff will continue as needed. Where new BMP controls are determined to be required, they will be installed and maintained. Once drilling operations have been completed and prior to beginning production, parts of the well pad will be reclaimed. Initial pad reclamation is accomplished by backfilling the reserve pit, Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 15 Piceance Basin Natural Gas Development Program contouring the disturbed soils to conform to the surrounding terrain, replacing stockpiled top soil, seeding of disturbed soil areas in order to reestablish a cover vegetation, and construction of erosion and sediment control structures. Oil and gas sites are considered stabilized once site preparation and interim reclamation are complete, and the above final stabilization criteria have been met, even though the site will be disturbed again in the future for final reclamation. Interim reclamation consists of minimizing the footprint of disturbance by reclaiming all portions of the well site not needed for production operations. The portions of the well site not needed for operations and safety purposes will be re -graded to final or intermediate contours that blend with the surrounding topography as much as possible. Topsoil will be re -spread over areas not needed for all weather purposes. "Final stabilization" means that all ground surface disturbing activities at the site have been completed, and all disturbed areas have been either built on, paved, or a uniform vegetative cover has been established with an individual plant density of at least 70 percent of per -disturbance levels. 4.2. Pipeline Completion and Reclamation Pipeline route reclamation involves placing fill in trenches, compacting fill, re -grading cut and fill slopes to restore the original contours, replacing topsoil, installing temporary waterbars and silt fencing only where necessary to control erosion, and re -vegetation. Waterbars and other appropriate BMPs must be maintained and repaired as necessary. Following successful re - vegetation, remaining waterbars are to be flattened to blend with the slope. 4.3. Road Completion and Reclamation Maintenance activities normally required during road completion and reclamation activities include blading, surface replacement, dust control, spot repairs, slide removal, ditch cleaning, culvert cleaning, litter pickup, noxious weed control, maintenance of interim reclamation, and snow removal. Additional inspections and maintenance may be needed during periods of snowmelt or heavy, prolonged rainfall to look for drainage, erosion, or sedimentation problems. Re -vegetation of road ditches and cut and fill slopes will help stabilize exposed soils and reduce sediment loss, reduce the growth of noxious weeds, reduce maintenance costs, maintain scenic quality and forage, and protect habitat. To ensure successful growth of vegetation, topsoil must be stored in designated stockpiles (where available) during road construction and re -distributed on cut slopes, fill slopes, and borrow ditches prior to re -vegetation activities. 4.4. Facilities Production Activities and Reclamation Many of the facilities constructed will be active for as long as the field is in production. As part of operations, materials and chemicals may be stored onsite. All product and any generated wastes will be placed and stored in the proper receptacles prior to use or removal for off-site disposal. Where appropriate, secondary containment may be provided for storage of materials, chemicals, and wastes and/or stored in an appropriate building / cabinet. All chemical storage will be in accordance with the Piceance Basin Field SPCC plan. Housekeeping will be maintained in all chemical storage areas. All containers are to remain closed except when transferring materials in and out of the container. Where appropriate, materials will be stored to prevent their containers from being exposed to precipitation events. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 16 Piceance Basin Natural Gas Development Program Interim reclamation consists of minimizing the footprint of disturbance by reclaiming all portions of the site not needed for support of production operations. The portions of the site not needed are to be re -graded to a final or intermediate contour that blends with the surrounding topography as much as possible. Topsoil will be re -spread over areas not needed for all weather purposes and the areas will be re -vegetated with native grasses. "Final stabilization" means that all ground surface disturbing activities at the site have been completed, and all disturbed areas have been either built on, paved, or a uniform vegetative cover has been established with an individual plant density of at least 70 percent of per -disturbance levels. Documented inspections will be performed during this period to ensure proper site stabilization. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron Nonh American Exploration and Production Company 17 Piceance Basin Natural Gas Development Program 5.0 FINAL RECLAMATION Following the development and production phases, pad areas will be reclaimed by contouring disturbed soils to conform to the surrounding terrain, replacing the stockpiled top soil, seeding of disturbed soil areas in order to re-establish cover vegetation, and construction of erosion and sediment control structures and BMPs that will remain in place following the development and production phases, as needed. Once stabilization is achieved, defined as uniform vegetative cover established with a density of at least 70 percent of pre -disturbance levels, a well pad may be removed from the SWMP inspection requirements. BMPs will stay in effect as an ongoing company practice to ensure proper management of storm water protection. If petroleum hydrocarbons or other chemicals impact storm water as a result of industrial activities onsite, the impacted storm -water will be addressed by following the Piceance Basin Field SPCC plan. 5.1. Well Pads - Final Reclamation The site will be reclaimed after the end of its operational life in accordance with local, state and federal requirements. Following well plugging, reclamation activities will include removing all production equipment and re -grading the site to the original contours of the surrounding terrain. All excavations and pits must be closed by backfilling when they are dry and free of waste. Subsequent steps include replacement of topsoil, re -vegetation of the site with the appropriate seed mix (see URS Specification for the Re -vegetation of Disturbed Areas attachment), and installation and maintenance of storm -water controls until final stabilization is achieved. Water breaks and terracing should only be installed when absolutely necessary to prevent erosion of fill material and should be removed when the site is successfully re -vegetated and stabilized. 5.2. Pipeline - Final Reclamation Final abandonment of pipelines and flowlines will involve flushing and properly disposing of any residual fluids remaining in the lines. All pipeline sections that have become exposed due to water or wind erosion, soil movement, or anticipated subsequent use, must be removed. Deeply buried lines may remain in place unless otherwise directed by the authorizing agency. 5.3. Roads - Final Reclamation Roads used to access oil and gas locations are typically constructed for that primary purpose, are rarely permanent, and exist only as long as necessary to complete exploration and production operations. Final reclamation includes re -grading the road back to the original contour, seeding, controlling noxious weeds, and may include other techniques to improve reclamation success such as ripping, scarifying, replacing topsoil, placing waterbars, pitting, and mulching. Seeds of native, perennial species will be used. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 18 Piceance Basin Natural Gas Development Program 5.4. Facilities - Final Reclamation The site will be reclaimed after the end of its operational life in accordance with local, state and federal requirements. Reclamation activities will include removing all buildings and equipment and re -grading the site to the original contours of the surrounding terrain. Subsequent steps include replacement of topsoil, re -vegetation of the site with the appropriate seed mix, and installation and maintenance of storm -water controls until final stabilization is achieved. Water breaks and terracing should only be installed when absolutely necessary to prevent erosion of fill material and should be removed when the site is successfully re -vegetated and stabilized. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 19 Piceance Basin Natural Gas Development Program 6.0 POTENTIAL POLLUTION SOURCES Potential pollution sources associated with construction sites and natural gas development include: • Sediment resulting from erosion of soil stockpiles and other areas cleared of vegetation; • Leakage of fuels and lubricants from equipment and spills from fueling; • Trash and debris from clearing activities, construction materials, and workers; • Leakage from portable restroom facilities; • Leakage or spills from storage tanks and process equipment associated with natural gas development; • Concrete washout water; and • Vehicle tracking. The most common source of pollution from pad and access road construction is sediment, which can be carried away from the work site with storm -water runoff and impact the water quality of a receiving stream. Clearing, grading, and otherwise altering previously undisturbed land can increase the rate of soil erosion over pre -disturbance rates. Refined petroleum products can also be potential storm -water pollutants. These products are used in construction activities to power or lubricate equipment and include: fuel, gear oil, hydraulic oil, brake fluid, and grease. Loading and unloading of condensate and produced water to and from above ground storage tanks and transfer vehicles (tanker trucks) are common and regular activities within the Skinner Ridge project area and represent storm -water contamination potential. Debris from laydown areas, residue from equipment cleaning and maintenance, and solid waste generated from land clearing operations and human activity (trees, brush, paper, trash, etc.) present other potential pollution sources within the construction and natural gas exploration and production and operations site. Spills or leaks from potential sources are described in detail in the SPCC plan. Response to certain events may require specialized training due to health and safety concerns. For a list of down -hole chemicals used during development activities please refer to the Down -Hole Chemical List provided as an attachment to this plan. Servicing and improper installation of portable restrooms is a potential source of biocides and wastewater that may enter nearby waterways. Concrete trucks must be rinsed out prior to leaving the site and this water has the potential to contaminate storm water if not properly handled. Typically concrete wash out waters will be diverted to reserve pits or other designated earthen impoundments to capture and evaporate wash out water and properly manage residual solids. The large vehicles used on the construction sites have the potential to accumulate a large amount of mud on their tires and undercarriages. If not removed, this mud could be tracked onto roads and later washed into nearby creeks. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 20 Piceance Basin Natural Gas Development Program 7.0 CONTROL MEASURES — GENERAL DESCRIPTIONS The objective of erosion and sediment controls is to minimize the release of sediments carried to waterways by storm -water runoff. This objective can be accomplished through the use of structural and/or nonstructural controls. The following sections provide a description of typical BMPs, including physical structures, employed to prevent soil erosion; work practices and managerial controls used to prevent storm -water impacts; and fuels, chemicals, and materials handling practices. The use of a combination of physical BMPs; good work practices; and storage of fuels, chemicals, and materials in covered and areas provided with secondary containment will prevent and/or minimize storm -water impacts. 7.1. Soil Erosion and Sediment Controls The objective of erosion and sediment controls is to minimize the release of sediments carried to waterways by storm -water runoff. This can be accomplished through the use of structural and/or nonstructural controls. This section briefly describes the physical erosion and sediment controls to be used at active construction sites to minimize possible sediment impacts to storm -water runoff. For specific BMP installation details and selection guidelines refer the Typical Storm - Water BMP Details provided as an attachment to this plan. The attachment includes detailed descriptions of BMPs, including information on where and when the use of individual BMPs is recommended; limitations and where and when they should not be used; construction details and maintenance requirements; and associated photographs and figures. 7.1.1. Sediment Control Berms A sediment control berm is a ridge of compacted soil located at the top or base of a sloping disturbed area to contain or divert surface runoff. Where used, soil berms shall be constructed of soil with sufficient fines to minimize flow through the berm. The purpose of a berm is to control runoff velocity, divert onsite surface runoff to a sediment trapping or filtration device and/or divert clean water away from disturbed areas. 7.1.2. Check Dams Check dams are small, temporary dams constructed across a diversion or roadside ditch. Check dams can be constructed using gravel, rock, gravel bags, geo-ridges, earth with erosion control blanketing/matting, straw bales, or erosion/sediment control log/wattles and are used to slow the velocity of concentrated flow in a channel. As a secondary function, check dams can also be used to catch sediment from the channel itself or from the contributing drainage area as storm -water runoff flows through or over the structure. 7.1.3. Culverts Culverts are typically used to move ditch water under roads or to direct stream flow under the access roads. Culverts are typically constructed out of concrete, steel, aluminum, or plastic pipe. Where used, culverts should have inlet and outlet protection features to minimize erosion such as placing a non -woven textile material under rip rap at each end of the culvert. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storrs -Water Management Plan Chevron North American Exploration and Production Company 21 Piceance Basin Natural Gas Development Program 7.1.4. Culvert Inlet and Outlet Protection Culvert inlet and outlet protection are protective measure BMPs installed to prevent erosion, scour, and undercutting at culvert inlet and outlets. The most common materials used for culvert inlet and outlet protection are erosion control blankets/mats and riprap. These materials are placed at culvert inlets and outlets to prevent erosion, scour, and undercutting. 7.1.5. Diversions Permanent diversion berms and structures control storm -water runoff by using a channel and an earthen ridge to prevent sediment laden storm runoff from leaving the construction site, well pad or other disturbed area; to prevent flows from eroding slopes; and to direct sediment laden flows to a trapping device. Diversions are most often constructed of earthen materials with vegetative cover and are best used with channel linings such as vegetation or matting. Diversions are typically used wherever the direction and velocity of runoff from up slope areas needs to be controlled. A good example would be diverting upgradient surface runoff away from a well pad. Channels and berms must be designed to manage peak storm flow and must be stabilized to prevent erosion of the channels. 7.1.6. Drainage Dips Drainage dips intercept and remove surface water from the access roads, pads, facilities, pipelines, and roadside ditches (before the combination of water volume and velocity begin to create erosion). Drainage dips are constructed diagonally across the flowline of the surface water and will allow the passage of slow traffic while dispersing surface water. 7.1.7. Erosion Control Blankets and Mats Erosion control blankets, and turf reinforcement mats (TRM), are porous fabrics and are manufactured by weaving or bonding fibers made from organic or synthetic materials together to create a fabric blanket or mat. Erosion control blankets and TRMs are installed on steep slopes, over berms, or in channels to prevent erosion until final vegetation is established. Erosion control blankets and TRMs can also be used as separators or to aid in plant growth. 7.1.8. Filter Berms A filter berm is temporary ridge made up of natural materials that already occur on the project site. Brush filter berms use small tree branches, root mats, grass, leaves, stone or other debris or material naturally available or left over from the site clearing and grubbing. Rock filter berms use site gravel, stone, or rock. Both types of filter berms are placed along a level contour to slow, filter, and divert flow and act as an efficient form of sediment control. 7.1.9. Georidge GeoRidge® is a permeable ditch berm designed for erosion and sediment control. The use of GeoRidge® reduces flow velocities and provides a smoother water flow resulting in less erosional energy, and thus minimizing the problem of downstream sediment transport and deposition. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 22 Piceance Basin Natural Gas Development Program 7.1.10. Gravel Surfacing Gravel surfacing may be used to cover soil in areas of high traffic such as roads, facility areas, and areas near the well heads. Gravel surfacing forms a layer that protects and minimizes soil erosion and vehicle soil tracking. 7.1.11. Land Grading Grading involves reshaping the ground surface to planned grades as determined by an engineering survey, evaluation, and layout. Grading provides more suitable topography for well pads, pipelines, facilities, and access roads, and helps to control surface runoff, soil erosion, and sedimentation during and after construction in these areas. Grading also includes road crowning and sloping to properly route runoff off roads. 7.1.12. Level Spreader A level spreader is a BMP used to prevent erosion and to improve infiltration by spreading concentrated storm -water runoff evenly over the ground as shallow sheet flow instead of through channels. It usually involves a depression in the soil surface that disperses flow onto a flatter area across a slight slope and then releases the flow onto level vegetated areas. This reduces flow speed, increases infiltration rates, and promotes evaporation. 7.1.13. Mulching Mulching is a temporary erosion control practice in which materials such as grass, straw, hay, wood fibers or wood chips are placed on exposed or recently planted soil surfaces. Mulching stabilizes soils by minimizing rainfall impact (rilling) and reducing storm -water runoff velocity. When mulching is used in combination with seeding, surface soils retain moisture, promote seed germination, and help insulate roots from extremes temperatures. 7.1.14. Retaining Walls Retaining walls are structures that are used to stabilize and hold soil in place, gain space on roadways or well pads, or to keep soil contained within a site boundary. This BMP can be constructed with rock, boulders, and/or cement blocks. 7.1.15. Re -vegetation Re -vegetation involves planting seed to establish a vegetative cover on disturbed areas. Re - vegetation reduces erosion and sedimentation by stabilizing disturbed areas in a manner that is economical and adaptable to site conditions. It also reduces runoff volumes by increasing water percolation into the soil, binds soil with roots, and protects soil from wind erosion. The permanent seed mix, rate, and application method is detailed in the URS Specification for the Re - vegetation of Disturbed Areas, which is provided as an attachment to this plan. 7.1.16. Riprap Riprap is a permanent, erosion -resistant layer made of stones, rock, or boulders. It is intended to stabilize areas subject to erosion and protect against scour of the soil caused by concentrated, high velocity flows. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 23 Piceance Basin Natural Gas Development Program 7.1.17. Roadside Ditches and Turnouts Roadside ditches are channels constructed parallel to roads. The ditches convey concentrated runoff of surface water from roads and surrounding areas to a stabilized outlet. Turnouts are used to effectively remove run-off water from the roadside ditch into well -stabilized areas before it reaches a waterway. 7.1.18. Sediment Traps Sediment traps are intended to intercept, trap, and retain sediment from runoff while allowing detained and clarified runoff to slowly drain, infiltrate, or both. They are usually installed in a drainage way or other point of discharge from a disturbed area. This BMP is formed by excavating below grade and/or constructing an earthen embankment with a protected spillway to slow the release of runoff. 7.1.19. Silt Fence Silt fences are used as temporary perimeter control structures that are designed to slow, temporary impound, and filter sediment laden water. Installation techniques and maintenance is critical to proper performance. 7.1.20. Slope Drains Slope drains are used with earth dikes and drainage ditches to intercept and direct surface flow away from sloped areas to protect cut or fill slopes. A slope drain is applicable for any construction site where concentrated surface runoff can accumulate and must be conveyed down a slope in order to prevent erosion. The slope drain may be a rigid pipe such as corrugated metal, flexible conduit or a lined terrace drain with the inlet placed at the top of the slope and the outlet at the bottom of the slope. Inlets must be securely anchored and outlets must be stabilized with riprap. 7.1.21. Stabilized Construction Entrance A stabilized construction entrance is a pad of gravel laid over filter cloth where construction traffic will be entering or leaving a construction site to or from a public right-of-way, street or highway. This is also referred to as vehicle tracking control. The purpose of a stabilized entrance to a site is to minimize the amount of tracked mud and dust that leaves the site and is carried onto county roads or state highways. As a vehicle drives over the gravel, mud and sediment are removed from the vehicle's wheels and undercarriages reducing off-site soil transport. This BMP reduces erosion and prevents tire rutting, as the filter fabric separates the gravel from the soil below and minimizes the migration of gravel into subsurface soil due to heavy vehicle loads. A stabilized construction entrance should be used at all major facility ingress and egress locations. 7.1.22. Straw Bale Barriers A straw bale barrier is a series of entrenched and staked straw bales placed on a level contour to intercept sheet flows. The barrier reduces runoff velocity and filters sediment laden runoff from the drainage of small areas of disturbed soil. This BMP may also be used to protect against erosion in small shallow drainage channels. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 24 Piceance Basin Natural Gas Development Program 7.1.23. Erosion/Sediment Control Log/Wattles Erosion/sediment control log/wattles or rolls are intended to capture and keep sediment on slopes or in small shallow drainage channels. Straw rolls can be used to temporarily stabilize slopes by reducing soil creep, sheet and rill erosion until permanent vegetation can be established. Straw rolls will last an average of one to two years. 7.1.24. Surface Roughening Soil surface roughening is a temporary erosion control practice often used in conjunction with grading. Soil roughening involves increasing the relief of a bare soil surface with horizontal grooves (corrugating) or tracks (tracking) using construction equipment. Slopes that are not fine graded and that are left in a roughened condition can reduce erosion, trap sediment, and prepare ground surfaces for seeding. 7.1.25. Terracing Terraces are made of either earthen embankments or ridge and channel systems that are properly spaced along a fill slope. Terraces are constructed with an adequate grade to promote drainage to a stabilized outlet. They reduce damage from erosion by collecting and redistributing surface runoff to stable outlets at slower speeds and by decreasing the distance of overland runoff flow. They also surpass smooth slopes in holding moisture and help to minimize sediment loading of surface runoff. 7.1.26. Vegetative and Grass Buffer Vegetative and grass buffers are areas of either natural or established vegetation that are maintained to protect the water quality of neighboring areas. Vegetive and grass buffers reduce storm -water runoff velocity, prevent soil erosion, promote infiltration and act as a filter to remove sediment. 7.1.27. Waterbars A waterbar is an earthen ridge, or ridge and channel, constructed diagonally across a slope road, trail, or disturbed area. Waterbars are normally used for drainage and erosion protection of closed, blocked, or infrequently used roads to divert storm -water runoff and minimize erosion. 7.1.28. Diversion Ditch/Berms A diversion ditch/berm is a small, temporary earthen channel or berm used to divert and convey runoff, usually to a sediment basin, trap, or pond. Depending on slope and anticipated flows, the diversion ditch may need to be lined with erosion control blankets/mats, check dams, or plastic (temporarily). 7.1.29. Slope Stabilization Slope stabilization generally pertains to structures or other BMPs that stabilize slopes that cannot be stabilized with vegetation. These structures and BMPs may include gabions and retaining walls. Some of these structures and BMPs are also used to stabilize stream banks. Gabions are rectangular wire -mesh cages that are filled with rock and wired together to form a protective but permeable structure for slope stabilization and erosion control. Gabions can be used as retaining Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 25 Piceance Basin Natural Gas Development Program walls to mechanically stabilize steep slopes, or for revetments, weirs, channel linings, culvert headwalls, and culvert outlet aprons. They are particularly useful where seepage is anticipated. 7.1.30. Concrete Washout Facilities Concrete washout facilities are used to prevent or reduce the discharge of pollutants to storm - water from concrete waste by conducting washout offsite, performing onsite washout in a designated area, and training employee and subcontractors. 7.1.31. Sanitary/Septic (Port -O -Let) Waste Management Proper sanitary and septic waste management prevents the discharge of pollutants to storm -water from sanitary and septic waste by providing convenient, well-maintained facilities, and arranging for regular service and disposal. Temporary sanitary facilities should be located away from drainage facilities, watercourses, and from traffic circulation. Temporary sanitary facilities should be secured to prevent overturning due to high winds or risk of high winds. Only reputable, licensed sanitary and septic waste haulers should be used. Untreated raw wastewater should never be discharged or buried. Regular waste collection by a licensed hauler should be arranged before facilities overflow. 7.1.32. Inlet Protection Inlet protection is a sediment control barrier formed around a storm drain inlet. A number of alternative inlet protection designs are available, including silt fences, straw bale barriers, block and gravel bags, and curb socks and sandbags. 7.2. Sources of Additional BMPs The structural and non-structural BMPs listed above are intended to include BMPs that may be used for gas gathering projects. However, there may be situations where a BMP is needed but not included above or project personnel may need additional information on the use, specification, and maintenance of BMPs. Additional information resources are listed below: • For oil and gas operations, the Bureau of Land Management and U.S. Forest Service have developed "Surface Operating Standards and Guidelines for Oil and Gas Exploration and Development," "Gold Book." The most recent version (fourth edition) of this is available on the internet at http://www.blm.gov/bmp/GoldBook Draft v12.pdf. • For construction BMPs the Urban Drainage and Flood Control District, a Colorado front range group of city and county agencies has developed a BMP manual that is available on the intemet at http://www.udfcd.org/usdem/vol3.htm • For construction BMPs and surface stabilization methods, the Alabama Soil and Water Conservation Committee has developed "Erosion Control, Sediment Control and Stormwater Management on Construction Sites and Urban Areas, Volume 1 Developing Plans and Designing Best Management Practices." This information is available on the internet at http://swcc.state.al.us/pdf/ASWCC June 2003 Alabama Handbook Construction E&S Control.pdf • For access roads, the US Forest Service and Bureau of Land Management have developed "Low -Volume Roads Engineering, Best Management Practices Field Guide," which is available on the intemet at http://www.blm.gov/bmp/field%20guide.htm Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 26 Piceance Basin Natural Gas Development Program 7.3. Management of Storm -Water Controls Structural BMPs will be installed, inspected, and maintained as needed. Detailed descriptions of typical BMPs that may be used on individual construction sites are provided in the Typical Storm -Water BMP Details attachment. This SWMP will be revised as needed to address new disturbances. Depending on the type and location of new facilities there may be a need for inclusion of new and different BMPs. In general, new development should be planned with consideration for storm -water quality (e.g. minimize disturbed area and maximize distance from surface water drainages, as practicable). Other developments on the property, primarily existing and/or improved roads, not currently or specifically addressed in the SWMP, will be periodically inspected for the evidence of erosion and drainage problems. This is especially important for access roads located within 100 feet of surface drainages or creeks. If problems are noted, they should be reported to the Operations Supervisor and/or Chevron SWMP Administrator. Problem areas may be addressed through construction activities, but will likely need to be addressed through the application of BMPs that will be added to the plan as needed. 7.4. Other Controls Well pad construction and drilling will generate various other wastes during the course of construction. Other wastes may include the following: • Sagebrush, shrubs and trees from clearing operations; • Trash and debris from construction materials and workers; • Drill cuttings, drilling fluids, frac sand, completion fluids; and • Sanitary sewage. Each of these wastes will be managed so as to not contribute to storm -water pollution. Construction trash and debris will be collected in containers and hauled off-site for disposal in suitable landfills. Sanitary waste will be containerized in portable toilets or other storage tanks with waste materials regularly pumped and transported off-site for disposal at approved facilities. 7.4.1. Fuels and Materials Management Petroleum products which may be present at the construction site include: gasoline, diesel fuel, lubricant oils, hydraulic oils, used oils, and solvents. Gasoline, diesel fuel, lubricant, hydraulic, and miscellaneous oils and solvents will be stored in portable storage tanks with secondary containment. Pollutants from petroleum products used during construction activities adhere easily to soil particles and other surfaces. In case of a spill or leak, soils contaminated with petroleum products will be containerized and transported to a proper treatment or disposal site. Proposed soil erosion and sediment control practices will aid in retention of spills or leaks. Use of secondary containment and drip pans will reduce the likelihood of spills or leaks contacting the ground. Proposed maintenance and safe storage practices will reduce the chance of petroleum products contaminating the site. Oily wastes such as crankcase oil, cans, rags, and paper containing oils will be placed in proper receptacles and disposed of or recycled. An additional source of petroleum contamination is Teaks from equipment and vehicles. Routine daily inspections will be conducted to identify leaks and initiate corrective actions, if needed. The Program SPCC plan and/or Emergency Response Plan will be activated as appropriate to manage any petroleum product spills. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 27 Piceance Basin Natural Gas Development Program The following guidelines for storing and managing petroleum products will be used: • All product containers will be clearly labeled. • Drums will be kept off the ground within secondary containment and stored under cover if needed. • Fuel tanks will be stored within secondary containment. • Lids of drummed materials will be securely fastened. • Emergency spill response procedures will be available onsite. • Spill clean up and containment materials (absorbent, shovels, etc.) will be easily accessible. Spills will be immediately cleaned up and contaminated materials will be properly stored onsite until they can be disposed of in accordance with applicable regulations. • Storage areas and containers will be regularly monitored for leaks and repaired or replaced as necessary. Contractors and subcontractors should be reminded about proper storage, handling and transferring of petroleum products or other hazardous materials during safety meetings. All spills and releases of exploration and production waste or produced fluid exceeding 5 barrels (210 gallons) including those contained within unlined berms, shall be reported in writing on the COGCC SpilURelease Report Form 19 within 10 days of discovery. All spills/releases that exceed 20 barrels (840 gallons) of exploration and production liquids/waste shall be verbally reported to the COGCC at (303) 894-2100 within 24 hours of discovery. Spills or releases of any size that impact or threaten to impact any waters of the state, residence or occupied structure, livestock, or public byway, shall be verbally reported to the COGCC as soon as practical after discovery (COGCC Rule 906). If the spill may reach waters of the state (which includes surface water, ground water and dry gullies or storm sewers leading to surface water), it must also be reported immediately to the CDPHE at 1-877-518-5608 and the National response Center at 1-800-824-8802. Spills or releases of more than 25 gallons of refined petroleum crude oil products such as gasoline, diesel fuel, oil, or derivatives of mineral, animal or vegetable oil shall be reported to the state of Colorado Division of Oil and Public Safety at (303) 318-8547 within 24 hours. A hazardous substance release in any amount which enters or threatens to enter waters of the state shall be reported to CDPI-IE and the National response Center at 1-800-824-8802. 7.4.2. Other Chemicals Products Management Additional materials will be used and stored onsite for use in construction. These materials will be stored appropriately and managed to minimize spills and leaks. Storage areas will be regularly inspected and any minor spills or leaks will be cleaned up immediately. 7.4.3. Materials Management The construction contractor will maintain a laydown or staging area for equipment and materials stored onsite. These areas will be maintained with good housekeeping and will be inspected on a regular basis for spills, leaks, and potential of materials commingling with storm -water runoff. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Stotm-Water Management Plan Chevron North American Exploration and Production Company 28 Piceance Basin Natural Gas Development Program 7.5. Construction Site Housekeeping Housekeeping will consist of neat and orderly storage of materials and containerized fluids. Wastes will be temporarily stored in containers and regularly collected and recycled, treated, or disposed of at approved off-site facilities. If spills occur prompt cleanup is required to minimize any commingling of waste materials with storm -water runoff. Routine equipment maintenance will be limited to fueling and lubrication. Drip pans and/or adsorbent material will be used during routine fueling and lubrication activities to contain spills or leaks. Any waste products generated from maintenance activities will be containerized and transported off-site for treatment, disposal, or recycling. All attempts will be made to minimize major equipment overhauls conducted onsite. Equipment will be transported off-site for major overhauls if required. Cleanup of trash and discarded materials will be conducted during the course of each work day. Cleanup will consist of patrolling the roadways, access areas, and other work areas to pickup trash, scrap debris, other discarded materials, and any contaminated soil. These materials will be recycled, treated, or disposed of appropriately. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 29 Piceance Basin Natural Gas Development Program 8.0 INSPECTION AND MAINTENANCE PROCEDURES To meet requirements of the General Permit inspection and maintenance of erosion and sediment control BMPs must occur during the project. Continued inspection and maintenance is required for specific structures after construction is completed. The inspection program will include the following: 1. A trained and qualified person familiar with the SWMP and storm -water control BMPs will conduct facility inspections and complete the Storm -Water Field Inspection Report Form provided as an attachment. 2. Inspections will cover these areas: • Evidence of surface erosion for disturbed areas; • Material and chemical storage areas; • Best Management Practices (BMPs); • Surface water diversions and down gradient areas; • New access roads and ditches; and • Locations where vehicles enter or exit the site. 3. Routine Inspections will occur at least once every 14 calendar days and within 24 hours after a significant precipitation or snow melt events that causes runoff; if no construction activities occurs following a storm event, post -storm event inspections shall be conducted prior to re -commencing construction activities but no later than 72 hours following the storm event; depending on safety concerns. 4. Permanently stabilized areas will be periodically inspected to monitor ongoing conditions. 5. A log of inspections will be completed and maintained for a minimum of three years. A copy of the SWMP will be kept at the Hiner Gate Field Office. 6. Inspections are not required for disturbed areas when snow cover exists over the entire site for an extended period as long as melting conditions that create runoff do not exist. 7. Water quality will be visually assessed for all receiving streams and discharge areas during each inspection if present. 8. Disturbed areas and material storage areas that are exposed to precipitation will be inspected for evidence of pollutants entering nearby drainages. 9. Check dams, wattles/logs, and other BMPs will be inspected for evidence of deterioration, under -cutting, and build up of sediment. Sediment will be removed when it has built up one-third to one-half the height of the hay bales or wattles/logs. 10. Roads used for vehicle access will be inspected for evidence of off-site sediment transport. 11. The SWMP will be modified as necessary whenever there is a change in design, construction or operation that changes the potential for pollutant discharge to waters of the state. 12. An inspection report summarizing the scope of the inspection, the name of the person conducting the inspection, date of inspection, and observations relating to the implementation will be completed for each inspection conducted. An example inspection Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 30 Piceance Basin Natural Gas Development Program report is provided as an attachment to this plan (Storm -Water Field Inspection Report Form). 13. Actions taken to modify storm -water control measures will be recorded with inspection reports and maps, and maintained with the SWMP. Personnel performing facility inspections of access roads, well pads or other operational facilities will record site conditions on the Storm -Water Field Inspection Report Form (see attachment). When deficiencies are discovered, the Chevron local contact will be immediately informed of the circumstances and this individual will direct designated subcontractors to perform BMP maintenance or replacement. Maintenance will include prompt adjustments and repairs to erosion and sediment control structures and BMPs that are found to be performing inadequately or deteriorating. Signs of rill or gully surface erosion shall be repaired immediately. The Chevron local contact has the authority and will coordinate subcontractors to install new and or additional storm -water control BMPs as needed. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 31 Piceance Basin Natural Gas Development Program 9.0 NON -STORM -WATER DISCHARGES The extraction of natural gas can produce large quantities of water that are trapped in the formation along with the gas. The produced water requires both a short-term and long-term management strategy. Chevron's short-term strategy is to treat the produced water for reuse in drilling and well completion operations. Longer-term produced water handling options are currently under evaluation by Chevron. Performance of the produced water treatment system and separate produced water injection well tests will assist Chevron in the decision-making process whether to treat all of the produced water in excess of drilling and well completion needs for beneficial reuse or to inject the excess produced water. Risks associated with accidental releases of produced water to surface and groundwater can be minimized by use of water management methods that do not include surface storage. In addition, topography in Clear Creek Valley limits the location of surface ponds to only a few relatively level areas that include portions of the most productive agricultural land in the valley. Long-term produced water management strategies may include avoiding, as much as practical, the need for surface ponds. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 32 Piceance Basin Natural Gas Development Program 10.0 FINAL STABILIZATION Areas which have been disturbed are considered to be stabilized when a uniform vegetative cover with a density of 70 percent of the pre -disturbance levels has been established or when an equivalent permanent, physical erosion reduction method is in-place. The disturbed areas will be seeded and mulched for final stabilization. The URS Specification for the Re -vegetation of Disturbed Areas (see attachment) details approved seed mixtures and application rates for the Program area. Typical Pure Live Seed application rates are recommended to be doubled if seeding is performed by hydroseeding or broadcasting. Areas not used for facilities, access roads, materials storage yards, or other work areas will be stabilized with vegetation. Areas that are stabilized with vegetation will be considered to have achieved final stabilization when a uniform stand of vegetation with a density of at least 70 -percent of the pre -disturbance has been established. Sprayed on mulches and other slope stabilization materials may be used in combination with seeding techniques in select areas to promote and establish surface vegetation cover. Other areas which may include facilities, access roads, materials storage yards, and other work areas will be stabilized with the use of permanent, physical erosion reduction methods which include, but are not limited to: 1. Surface hardening — covering of the soil surface with hardened products such as concrete or asphalt pavement. 2. Surface covering — covering of the surface soil with structures that inhibits contact of precipitation with the soil surface, which is generally considered to be the placement of a structure (building or tank) over the soil surface. 3. Gravel surfacing — gravel surfacing will be applied in areas such as access roads, materials storage yards, and other work area surfaces. Some gravel may be lost due to erosion from intense precipitation events or due to vehicle traffic. Gravel surfaces will be periodically inspected to determine the need for gravel replacement. Gravel surfaces will be replaced or repaired (through grading) when inspection reveals that the gravel surface is no longer effectively covering the soil surface. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Stonn-Water Management Plan Chevron North American Exploration and Production Company 33 Piceance Basin Natural Gas Development Program 11.0 OWNER/APPLICANT CERTIFICATION I certify under penalty of law that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gather and evaluate the information submitted. Based on my inquiry of the person or persons who manage the system, or those persons directly responsible for gathering the information, that the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations. Signature: Name: Title: Date: Owner Name: Michael DeBerry Piceance Basin Operations Manager Chevron U.S.A Inc. Owner Address:760 Horizon Drive Grand Junction, CO 81506 Site Name and Location: SWMP Prepared by: SWMP Updated by: Skinner Ridge Field Piceance Basin Field Operations Townships 5, 6, 7, 8 and 9 South Ranges 97 and 98 West Garfield County, Colorado Cordilleran Compliance Services, Inc. 826 21 V2 Road Grand Junction, CO 81505 Washington Group International / URS Washington Division 7800 E. Union Ave., Suite 100 Denver, CO 80237 Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 34 Piceance Basin Natural Gas Development Program STATE OF COLORADO Bill Ritter, Jr., Governor James B. Martin, Executive Director Dedicated to protecting and improving the health and environment of the people of Colorado 4300 Cherry Creek Dr. S. Denver, Colorado 80246-1530 Phone (303) 692-2000 TDD Line (303) 691-7700 Located in Glendale, Colorado http://www.cdphe.state.co.us July 30, 2007 Laboratory Services Division 8100 Lowry Blvd. Denver, Colorado 80230-6928 (303) 692-3090 Michael De Berry, Piceance Ops Mgr Chevron USA Inc, Hector E. Cavazos P.O. Box 36366 Houston, TX 77099 970/257-6005 RE: Final Permit, Colorado Discharge Permit System — Stormwater Certification No: COR -037787 Skinner Ridge Natural Gas Wells Garfield County Local Contact: George Badovinatz, Ops Super 970/257-6002 Dear Sir or Madam: Colorado Department of Public Health and Environment Enclosed please find a copy of the new permit and certification which have been re -issued to you under the Colorado Water Quality Control Act. Your old permit expired on June 30, 2007. This is a renewal to the permit, and replaces the old one. See page 2 of the Rationale (the pages in italics) for a summary of the changes to the permit. Your Certification under the permit requires that specific actions be performed at designated times. You are legally obligated to comply with all terms and conditions of the permit. Please read the permit and certification. If you have any questions please visit our website at : www.cdphe.state.co.us/wq/permitsunit/stormwater or contact Matt Czahor at (303) 692-3517. Sincerely, 0 COL Kathryn Dolan Stormwater Program Coordinator Permits Unit WATER QUALITY CONTROL DIVISION xc: Regional Council of Governments Local County Health Department District Engineer, Technical Services, WQCD Permit File STATE OF COLORADO COLORADO DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT WATER QUALITY CONTROL DIVISION TELEPHONE: (303) 692-3500 CERTIFICATION TO DISCHARGE UNDER CDPS GENERAL PERMIT COR -030000 STORMWATER DISCHARGES ASSOCIATED WITH CONSTRUCTION Certification Number COR037787 This Certification to Discharge specifically authorizes: Chevron USA Inc LEGAL CONTACT: Michael De Berry, Piceance Ops Mgr Chevron USA Inc P.O. Box 36366 Houston, TX 77099 Phone # 970/257-6005 LOCAL CONTACT: George Badovinatz, Ops Super, Phone # 970/257-6002 During the Construction Activity: Gas/Oil Field Exploration and/or Development to discharge stormwater from the facility identified as Skinner Ridge Natural Gas Wells which is located at: Tom Creek in Skinner Ridge area. Garfield County, CO Latitude 39.587, Longitude 108.341 In Garfield County to: -- Tom Creek Anticipated Activity begins 02/07/2005 continuing through 06/07/2006 On 3.4 acres (18.0 acres disturbed) Certification is effective: 07/01/2007 Certification Expires: 06/30/2012 Annual Fee: $245.00 (DO NOT PAY NOW — A prorated bill will be sent shortly.) Page 1 of 22 Chevron Michael DeBerry MCA Business Unit Manager, Piceance Chevron Operations 744 Horizon Ct. Ste. 140 Grand Junction, CO 81506 Tel 970-257-6005 Fax 970-255-6621 micd Pschevron.com August 15,2007 Colorado Department of Public Health and Environment Water Quality Control Division, Storm -Water Program WQCD-Permits-B2 4300 Cherry Creek Drive South Denver, CO 80246-1530 Subject: Amendment to Construction Storm -Water Permit COR -037787 Dear Sir/Madan: Chevron USA, Inc. currently holds a common plan of development permit for stoml-water discharges for the Skinner Ridge Natural Gas Wells in Garfield County, Colorado (Certification No: COR -037787). With this notification, we wish to convert our permit to a field permit and make the following revisions: Requested Information Revised Permit Information Permit Type Field Permit Site Address North end of County Road 211. Garfield County, CO Currently managed from the Chevron Grand Junction office: Chevron North America Exploration and Production Company 744 Horizon Court, #140 Grand Junction, Colorado 81506 Total Disturbed Acres (Life of Project)Construction Estimated disturbance over five years: 370+ acres activities will be phased, which will limit disturbance to 10 to 20 acres at a time. Sites will be stabilized as completed. Disturbance beyond five years will require re-evaluation. Description of Construction Activities The construction activity includes construction of well pads, access roads, utility corridors (gas and water pipelines, electricity, fiber optics, etc.), water impoundments, offices, living quarters, processing facilities, and other associated facilities required to construct and operate a natural gas well field. Storm -Water Discharges to: Clear Creek and associated tributaries; Conn Creek and associated tributaries; Brush Creek and associated tributaries, which drain to the Roan Creek basin and ultimately to the Colorado River. Also tributaries associated with West Parachute Creek, which drains to Parachute Creek and ultimately to the Colorado River. Site Map See attachment. The revised map shows areas that the Chevron Piceance Basin Natural Gas Development Program (Skinner Ridge Gas Field) is expected to affect over the next five years. July 20, 2007 Page 2 The master Storm -Water Management Plan for this Field Permit has been revised to reflect these changes, as well as additional information requested in the new permit, which took effect on July 1, 2007. Yours truly, Michael DeBerry Piceance Operations Manager Contact Information: Chevron North America E&P 744 Horizon Court; Suite 140 Grand Junction, CO 81506 (970) 257-6005 STATE OF COLORADO Bill Filter, Jr., Governor James B. Martin, Executive Director Dedicated to protecting and improving the health and environment at the people of Colorado 4300 Cherry Creek Dr. 9. Denver, Colorado 80246-1630 Phone (303) 692.2000 TDD Line (303) 691.7700 Located In Glendale, Colorado htlp//vmw.cdphe.state.co.us Laboratory Services Division 8100 Lowry Blvd. Denier, Colorado 80230-8928 (303) 692-3090 Robert L. Life, Rockies/CBM Ops. Mgr Chevron USA Inc, Kenneth W. Jackson 11111 S. Wilcrest P.O.Box 36366 Houston, TX 77099 Colorado Department of Public Health antiEntuonment February 16, 2007 RE: Construction Activity Stonnwater Discharge Permit — Reapplication — RESPONSE REQUIRED Chevron USA Inc - Skinner Ridge Natural Gas Wells CDPS Cert. No. COR -037787, Garfield County Dear Sir or Madam: The General Permit for Stormwater Discharges Associated with Construction (COR -030000) will expire on June 30, 2007. The Water Quality Control Division will reissue the permit before that expiration date. Our records indicate that you are currently covered by this permit for the above -referenced site. All permittees must complete the enclosed form and return if to our office by March 30, 2007. A self- addressed envelope is enclosed for your use. The form will indicate if you wish to maintain perrnit coverage past the June 30, 2007 expiration, or if you will inactivate your permit coverage prior to that date. Specifically, for those permittees requiring permit coverage past the permit expiration, you must complete and return the enclosed Reapplication and Record Verification form to maintain compliance with the stormwater regulation. Please refer to the Q&A section on the back of this letter for answers to commonly asked questions. If you have any further questions that are not addressed here, you may call our office at (303) 692-3517 or cdphe.wgstorm@state.co.us. However, due to the expected large volume of calls/emails, we may not be able to respond quickly. Thanks for your patience. Sincerely, Nathan Moore Environmental Protection Specialist Permits Unit WATER QUALITY CONTROL DIVISION Enclosures 2007 Renewal Form Page 2 oft Q: A: Permit Renewal Q&A What is this all about? Your construction site is certified under the Construction stormwater general permit. Stormwater general permits are issued fora five-year period, and expire after that time. This permit is about to expire. The attached form will indicate your intent to maintain permit coverage following June 30, 2007, or to inactivate prior to that date. The permit and regulation require that you either renew or inactivate your permit. Q: What dol need to do? A: You MUST complete one of the following three options. See the following question and answer if you are unsure of what the status of your site will be when the permit expires on June 30, 2007. 1) To KEEP permit coveraae — You must reapply. We have tried to make the reapplication process as simple as possible. Complete the attached enclosed Renewal Form for reapplication following these steps: • Check Box Ain Item I, indicating you wish to renew your coverage • Sign the Reapplication Certification in Item 2. • Review the information in Item 3 (Record Verification). If anything has changed or is incorrect, please cross out the old and write in the new. • Submit the completed Renewal Form by March 30, 2007. (Save a copy for your records.) -or- 2) To END permit coverage— IF the entire site has already been finally stabilized*, or will be finally stabilized prior to June 30, 2007, you still need to submit the attached form but also need to submit an Inactivation Form separately. Just follow these steps: • Renewal Form: Check Box B in Item 1, indicating you plan to inactivate your permit prior to June 30, 2007, and submit the completed Renewal Form by March 30, 2007, -AND- • Inactivation Form: Complete and sign a separate Inactivation Form, and submit k once the site has been finally stabilized*. A copy of the Inactivation Form was sent with your original permit. It can also be downloaded at: www.cdphe.state.co.ushvq/permitsunit/stormwater/swconinact.pdf *"Finally stabilized" means that all disturbed areas have been either built an. paved, ora uniform vegetative cover has been established with a density of at (east 70 percent of pre -disturbance levels, or equivalent permanent, physical erosion reduction methods have been employed. Re -seeding alone does not qualify. -or- 3) To TRANSFER permit coverage— If your part on a project is finished, but the project is still underway, the permit can be transferred to the site owner or new operator. If you plan to transfer the permit, you must still submit the renewal to maintain permit coverage as discussed in Item 1, above, even if you plan to transfer the permit prior to June 30. 2007. This will make sure that the permit coverage does not expire for either you, or the new permittee. When you are ready to transfer the permit, submit the Transfer Form, available at www.cdphe.state.co.us/wq/permitsunit/stormwater/transfer.pdf. More details on transfer procedures and transferring portions of a permitted site are available in our fact sheet (see bottom of page). What if I am unsure if the site will be ready for inactivation or transfer by June 30, 2007? If you are not sure right now if the site will be finally stabilized and ready for inactivation by June 30, 2007, or if you are not sure right now if you will transfer the permit, all you need to do is follow the renewal process in Item 1 above. After you have submitted the renewal form, you can still inactivate or transfer the permit at a later date, either before or after June 30. There is no extra fee involved with submitting the renewal, and this way you can make sure that your permit coverage is continued past June 30, 2007 if you still need it. Do I need to send any money? No - the billing process is handled separately. What changes will be in the new permit? Several changes are being proposed for the new permit, primarily to increase the clarity of permit requirements consistent with Division guidance currently available. When the permit is reissued and sent to you, Part LA of the Rationale will summarize all the changes made. The Division is currently in the process ofredrafting the permit, which includes the opportunity for public comment. If you would like to receive a copy of the public notice, or submit comments on the permit, please contact our office at cdphe.wgstorm@state.co.us or 303-692- 3517 (please provide an email address if possible). A Fact Sheet on the construction program with additional information about permit requirements, the transfer process, etc, is available at: www.cdphe.state.co.ushvq/PermitsUnit/stormwater/SWFaclsheet.pdf 2007 Renewal Form Page 2 of2 Q: A: Q: A: Qt A: COLORADO DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT Water Quality Control Division \VQCD-P-B2 4300 Cherry Creek Drive South Denver, CO 80246-1530 CONSTRUCTION ACTIVITY STORMWATER DISCHARGE PERMIT RENEWAL FORM REAPPLICATION & RECORD VERIFICATION (or Inactivation Intent) **RETAIN A COPY OF THIS FORM FOR YOUR RECORDS** COR -037787 This form is for reapplication for the Skinner Ridge Natural Gas Wells project/development (COR -037787) under the Construction Activity Stormwater Discharge Permit. You must complete the applicable sections of this form and submit it to the address in the top left corner by March 30, 2007. Do not send anv money with this form - the billing process is handled separately. More information about this process is contained in the cover letter and Q&A that accompany this form. STEP 1— Intent to Renew or Inactivate If you are unsure if the project will be finally stabilized by June 30, 2007, check Box A and complete the rest of this form (both sides) to renew your permit coverage. You can still submit the inactivation at a later time (see the Q&A). BOX A: Check this box to renew your permit certification and maintain permit coverage. Continue on to Steps 2 and 3, and then submit this form. BOX B: 0 I WILL BE INACTIVATING MY PERMIT COVERAGE BY JUNE 30, 2007 Check this box if your site will be finally stabilized by June 30, 2007. This will result in your certification not being renewed. You are still required to submit the Inactivation Form separately prior to June 30, 2007, certifying the site has been finally stabilized. See the Q&A for additional instructions (item 2 on the second question). It is not necessary to complete the rest of this form if you have checked Box B; the form is now ready to submit. STEP 2 — Reapplication Certification Complete this step if you checked Box A, above. An original signature is required. If the legally responsible person has changed from what is indicated in Step 3, below, the new person must be listed in that section and sign this certification. To complete this Reapplication, the Legally Responsible Person named in Step 3 must sign the following certification: / cert5' under penal°, of law that 1 have personally examined and am familiar with the information submitted on this form and that I believe that the information is true, accurate and complete. Further, 1 understand that by completing and returning this form,1 have applied for coverage under the revised general permit for Stornnvater Discharges associated with Constntction Activities. 1n1..6t H£crr>C e r✓F 7s /6 /may wo -- gnature of Legally Responsible P on Printed Name Date Signed STEP 3 — Record Verification The Record Verification section is located on the hack of this document. Complete this step if you checked Box A, above, and write in any new information. Note that ifyou have submitted amendments to your original application information previously, they would be reflected in your file at the Water Quality Control Division, but may not have been recorded in our database. If this is the case, please write in those previously submitted changes in this section. 2007 Renewal Form Page 1 of 2 OVER STEP 3, CONTINUED - Recon) Verification' Please review the information below carefully, and make whatever changes are necessary, by crossing out the incorrect information and writing in the new. If any items are blank (e.g., email), please fill in if available. Penalltee lntonnollon: Permittee Legally Responsible Person Phone - 4414+664.49tfin ciao-2f-6cor Email - Chevron USA Inc Kenneth W. Jackson /Waned be ges✓yr RobaakOpeltdgr riceo ce_ ogee';, Mailing Address StiliNEMItreest P.O. Box 36366 Houston, IX 77099 Name, location and description oceans:ruction project: Plan/Development Name - Site Address Site County Skinner Ridge Natural Gas Wells Tom Creek in Skinner Ridge area. Garfield County, CO Garfield Total Acres Disturbed Area Covered Under this Permit (Over the Life of the Project) 18.0 Brief Description of Nature of Construction Activities- - The construction activity includes the drilling of natural gas test wells, clearing of well drilling pads, construction of access roads, and the eventual construction of natural gas gathering pipelines. . Anticipated Consln,dion Schedule: This is only an estimated date and will not result in termination of your permit coverage if the dale is exceeded. Anticipated Date of Completion and Final Stabilization Local contact familiar wllh the she: Local Contact Local Contact Phone Local Contact Email SlonnwalerDiscimrces lo: Receiving Stream(s) -6/7/2006 - Tom Creek t t7ent- (dovintn+f ent' Sol Make certain this form has been signed. - See Item 2 on page 1 of this form. 2007 Renewal Fonn Page 2 of 2 STATE OF COLORADO Bill Owens, Governor Douglas H. Benevento, Executive Director Dedicated to protecting and improving the health and environment of the people of Colorado 4300 Cherry Creek Dr. 5. Laboratory and Radiation Services Division Denver, Colorado 80246-1530 8100 Lowry Blvd. Phone (303) 692-2000 Denver, Colorado 80230-6928 TDD-Une (303) 6917700 t;m) (.07 ;non Located in Glendale, Colorado Colorado D .pate.,, it of Public Health http://www.cdphe.state.co.us and Environment February 17, 2005 Robert L. Life, Rockies/CBM Ops. Mgr Chevron U.S.A. Inc. - Kenneth W. Jackson 11111 S. Wilcrest/P.O. Box 36366 Houston, TX 77099 281/561-4991 RE: Final Permit, Colorado Discharge Permit System — Stormwater Certification No: COR -037787, Garfield County Skinner Ridge Natural Gas Wells Local Contact: Sean Norris, Senior Project Geologist, 970/ 263-7800 Anticipated Activity: 02/07/2005 through 06/07/2006 On 3.4 acres (18.0 acres disturbed) Dear Sir or Madam: Enclosed please find a copy of the permit certification that was issued to you under the Colorado Water Quality Control Act. Your certification under the permit requires that specific actions be performed at designated times. You are legally obligated to comply with all tents and conditions of your certification. Note that the stormwater permit for construction activities now covers construction sites disturbing down to one acre (the previous threshold was 5 acres). Effective July 1, 2002, any construction activity that disturbs at least 1 acre of land (or is part of a larger common plan of development or sale that will disturb at least 1 acre) must apply for permit coverage. Please read the permit and certification. If you have any questions please visit our website at http://www.cdphe.state.co.us/wq/permitsunit/wqcdpmt.html, or contact Matt Czahor at (303) 692-3575. 64, Kathryn Dolan Stormwater Program Coordinator Permits Unit WATER QUALITY CONTROL DIVISION Enclosure xc: Regional Council of Governments Local County Health Department District Engineer, Technical Services, WQCD Permit File Fee File Permit No. COR -030000 Facility No. COR -037787 PAGE 1 of 17 CERTIFICATION CDPS GENERAL PERMIT STORMWATER DISCHARGES ASSOCIATED WITH CONSTRUCTION Construction Activity: The construction activity includes the drilling of natural gas test wells, clearing of well drilling pads, construction of access roads, and the eventual construction of natural gas gathering pipelines. This permit specifically authorizes: Chevron U.S.A. Inc. - Kenneth W. Jackson to discharge stormwater from the facility identified as Skinner Ridge Natural Gas Wells which is located at: Tom Creek in Skinner Ridge area. Garfield County, Co latitude 39.5877, longitude 108.3418 in Garfield County to: Tom Creek effective: 02/15/2005 Annual Fee: $449.00 (DO NOT PAY NOW. You will receive a prorated bill.) Page 2 of 17 Permit No. COR -030000 CDPS GENERAL PERMIT STORMWATERDISCHARGES ASSOCIATED WITH CONSTRUCTION ACTIVITY AUTHORIZATION TO DISCHARGE UNDER THE COLORADO DISCHARGE PERMIT SYSTEM In compliance with the provisions of the Colorado Water Quality Control Act, (25-8-101 et seq., CRS, 1973 as amended) and the Federal Water Pollution Control Act, as amended (33 U.S.C. 1251 et seq.; the "Act"), this permit authorizes the discharge of stormwater associated with construction activities certified under this permit, from those locations specified throughout the State of Colorado to specified waters of the State. Such discharges shall be in accordance with the conditions of this permit. This permit specifically authorizes the facility listed on page 1 of this permit to discharge stormwater associated with construction activity, as of this date, in accordance with permit requirements and conditions set forth in Parts I and II hereof. All discharges authorized herein shall be consistent with the terms and conditions of this permit. This permit and the authorization to discharge shall expire at midnight, June 30, 2007. Issued and Signed this 21st day of May, 2002 COLORADO DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT S,Gt.2i-- Fm. J. David Holm, Director Water Quality Control Division DATE SIGNED: MAY 21, 2002 EFFbCTIVE DATE OF PERMIT: JULY 1, 2002 TABLE OF CONTENTS PART I COVERAGE UNDER THIS PERMIT 3 1. Authority to Discharge 3 a) Applicable Sections 3 2. Industries Covered Under this Permit 3 \ T CJS a. 3 b) Types of Activities Covered by this Permit: 3 3. Permit Coverage Without Application 3 a) Applicable Sections 3 b) Local Agency Authority 3 c) Permit Coverage Termination 4 d) Compliance with Qualifying Local Program 4 e) Full Permit Applicability 4 4. Application, Due Dates 4 a) Application Due Dates 4 b) Summary of Application 4 5. Permit Certification Procedures 4 a) Request for Additional Information 5 b) Automatic Coverage 5 c) Individual Permit Required 5 d) Temporary Coverage 5 e) General vs. Individual Permit Coverage 5 0 Local Agency Authority 5 6. Inactivation Notice 5 7. Transfer of Permit 5 8. Permit Expiration Date 6 9. Individual Permit Criteria 6 8. CONTENTS OF THE STORMWATER MANAGEMENT PLAN 6 1. Site Description 7 2. Site Map 7 3. BMPs for Stormwater Pollution Prevention 7 a) Erosion and Sediment Controls 7 b) Materials Handling and Spill Prevention 8 4. Final Stabilization and Longterm Stormwater Management 8 5. Other Controls 8 6. Inspection and Maintenance 8 C. TERMS AND CONDITIONS 8 1. General Limitations 8 2. Prohibition of Non-stormwater Discharges 9 3. Releases in Excess of Reportable Quantities 9 4. Stonnwater Management Plans 9 a) Signatory Requirements 9 b) SWMP Review/Changes 9 5. Inspections 9 a) Active Sites 9 b) Completed Sites 10 c) Winter Conditions 10 6. Reporting 10 7. SWMP Submittal Upon Request 10 D. ADDITIONAL DEFINITIONS 10 -2a- TABLE OF CONTENTS (cont.) E. GENERAL REQUIREMENTS 11 1. Signatory Requirements 11 2. Retention of Records 12 PART II A. MANAGEMENT REQUIREMENTS 12 1. Change in Discharge 12 2. Special Notifications - Definitions 12 3. Noncompliance Notification 13 4. Submission of Incorrect or Incomplete Information 13 5. Bypass 13 6. Upsets 13 7. Removed Substances 14 8. Minimization of Adverse Impact 14 9. Reduction, Loss, or Failure of Treatment Facility 14 10. Proper Operation and Maintenance 14 B. RESPONSIBILITIES 14 1. Inspections and Right to Entry 14 2. Duty to Provide Information 15 3. Transfer of Ownership or Control 15 4. Modification, Suspension, or Revocation of Permit By Division 15 5. Permit Violations 16 6. Legal Responsibilities 16 7. Severability 16 8. Renewal Application - 17 9. Confidentiality 1' 10. Fees 17 11. Requiring an Individual CDPS Permit 17 -2b- PART I Page 3 Permit No. COR -030000 PART I n. COVERAGE UNDER THIS PERMIT 1. Authority to Discharge Under tis pemdm, eunsu acuqu ALbvILICS, nil, ludmg t,lcaiu,g, 614 dig, and w.cavatsun, a.c grant d at th,nzBNBH to discharge stormwater associated with construction activities into waters of the state of Colorado. a. Applicable Sections: This permit is made up of several parts, not all of which apply to all permittees. The permittee will be responsible for determining and then complying with the applicable sections, depending upon whether or not a Qualifying Local Program covers the site. For sites not covered by a Qualifying Local Program, all Parts of the permit except Part I.A.3 apply. 2. Industries Covered Under this Permit a) Definitions: 1) Stormwater: Stormwater is precipitation -induced surface runoff. 2) Construction activity: Construction activity includes clearing, grading and excavation activities. Construction does not include routine maintenance performed by public agencies, or their agents to maintain original line and grade, hydraulic capacity, or original purpose of the facility. 3) Small construction activity: Stormwater discharge associated with small construction activity means the discharge of stormwater from construction activities that result in land disturbance of equal to or greater than one acre and less than five acres. Small construction activity also includes the disturbance of less than one acre of total land area that is part of a larger common plan of development or sale, if the larger common plan will ultimately disturb equal to or greater than one and less than five acres. 4) Oualifying Local Program: This permit includes conditions that incorporate qualifying local erosion and sediment control program (Qualifying Local Program) requirements by reference. A Qualifying Local Program is a municipal stormwater program for stormwater discharges associated with small construction activity that has been formally approved by the Division. 5) Other Definitions: Definitions of additional terms can be found in Part I.D. of this permit. b) Types of Activities Covered by this Permit: This permit may authorize all new and existing discharges of stormwater associated with construction activity. This includes stormwater discharges from areas that are dedicated to producing earthen materials, such as soils, sand and gravel, for use at a single construction site. This permit also includes stormwater discharges from dedicated asphalt batch plants and dedicated concrete batch plants. This permit does not authorize the discharge of mine water or process water from such areas. 3. Permit Coverage Without Application — for small construction activities under a Qualifying Local Program only If a construction site is within the jurisdiction of a Qualifying Local Program, the operator of the construction activity is authorized to discharge stormwater associated with small construction activity under this general permit without the submittal of an application to the Division. a) Applicable Sections: For sites covered by a Qualifying Local Program, only Parts 1.A.1, I.A.2, 1.A.3, I.C.1, I.C.2, I.C.3, I.D and Part H of this permit, with the exception of Parts ILA. 1,11.B.3,1I.8.8, and II.B 10, apply. b) Local Agency Authority: This permit does not pre-empt or supersede the authority of local agencies to prohibit, restrict, or control discharges of stormwater to storm drain systems or other water courses within their jurisdiction. PART I Page 4 Permit No. COR -030000 A. COVERAGE UNDER THIS PERMIT (cont.) c) Permit Coverage Termination: When a site has been finally stabilized, coverage under this permit is automatically terminated. d) Compliance with Qualifying Local Program: A construction site operator that has authorization to discharge under this permit under Part I.A.3 shall comply with the requirements of the Qualifying Local Program with jurisdiction over the site. e) Full Permit Applicability: The Division may require any owner or operator within the jurisdiction of a Qualifying Local Program covered under this permit to apply for and obtain coverage under the full requirements of this permit. The owner or operator must be notified in writing that an application for full coverage is required. When a permit certification under this permit is issued to an owner or operator that would otherwise be covered under Part I.A.3 of this permit, the full requirements of this permit replace the requirements as per Part I.A.3 of this permit, upon the effective date of the permit certification. A site brought under the full requirements of this permit must still comply with local stormwater management requirements, policies or guidelines as required by Part I.C.I.h of this Permit. 4. Application. Due Dates a) Application Due Dates: At least ten days prior to the commencement of construction activities, the operator of the construction activity shall submit an application form as provided by the Division, with a certification that the Stormwater Management Plan (SWMP) is complete. One original completed discharge permit application shall be submitted, by mail or hand delivery, to: Colorado Department of Public Health and Environment Water Quality Control Division WQCD-P-B2 4300 Cherry Creek Drive South Denver, Colorado 80246-1530 b) Summary of Application: The application requires, at a minimum, the following: 1) The operator's name, address, telephone number, tax payer identification number (or employer identification number), and the status as Federal, State, private, public or other entity; 2) Name, county and location of the construction site, including the latitude and longitude to the nearest 15 seconds of the approximate center of the construction activity; 3) A brief description of the nature of the construction activity; 4) The anticipated starting date of the project and the anticipated schedule of completion 5) Estimates of the total area of the site, the area of the site that is expected to be disturbed, and the total area of the larger common plan of development or sale to undergo disturbance; 6) The name of the receiving water(s), or the municipal separate storm sewer system and the ultimate (i.e., named) receiving water(s); 7) Certification that the SWMP for the construction site is complete (see Part I.B. below); and 8) The signature of the applicant signed in accordance with Part I.E.1 of this permit. 5. Permit Certification Procedures If the general permit is applicable to the applicant's operation, then a certification will be developed and the applicant will be authorized to discharge stormwater under this general permit. A. COVERAGE UNDER THIS PERMIT (cont.) PART I Page 5 Permit No. COR -030000 a) Request for Additional Information: The Division shall have up to ten days after receipt of the above information to request additional data and/or deny the authorization for any particular discharge. Upon receipt of additional information, the Division shall have an additional ten days to issue or deny authorization for the particular discharge. (Notification of denial shall be by letter, in cases where coverage under an alternate general ptauui VI an iudividunl pcauut is atten ..d, aiatcad of ce....agc ,md.,, this per..,.t.) b) Automatic Coverage: If the applicant does not receive a request for additional information or a notification of denial from the Division dated within ten days of receipt of the application by the Division, authorization to discharge in accordance with the conditions of this permit shall be deemed granted. c) Individual Permit Required: If, after evaluation of the application (or additional information, such as the SWMP), it is found that this general permit is not applicable to the operation, then the application will be processed as one for an individual permit. The applicant will be notified of the Division's decision to deny certification under this general permit. For an individual permit, additional information may be requested, and 180 days will be required to process the application and issue the permit. d) Temporary Coverage: Notwithstanding Parts I.A.5.a-c, above, the Division reserves the right to temporarily cover stormwater discharge from construction activity under general permits, even though individual permit coverage may be more appropriate. Certification of these activities under a general permit does not in any way infringe on the Division's right to revoke that coverage and issue an individual permit or amend an existing individual permit. e) General vs. Individual Permit Coverage: Any owner or operator authorized by this permit may request to be excluded from the coverage of this permit by applying for an individual CDPS.pennit. The owner or operator shall submit an individual application, with reasons supporting the request, to the Division at least 180 days prior to any discharge. l) Local Agency Authority: This permit does not pre-empt or supersede the authority of local agencies to prohibit, restrict, or control discharges of stormwater to storm drain systems or other water courses within their jurisdiction. 6. Inactivation Notice When a site has been finally stabilized in accordance with the SWMP, the operator of the facility must submit an Inactivation Notice that is signed in accordance with Part I.E.I. of this permit. The Inactivation Notice form is available from the Division and includes: a) Permit certification number; b) The peruttee's name, address, telephone number; c) Name, location, and county for the construction site for which the application is being submitted. d) Certification that the site has been finally stabilized, and a description of the final stabilization method(s). An inactivation form may not be required for small construction activities if application was made for coverage with a completion date less than 12 months from the start of construction activity. In such cases, permit certification may be authorized for a predetermined period from 3 to 12 months. The permit certification will include the automatic expiration date for permit coverage. If permit coverage beyond that date is needed (i.e., the site has not been finally stabilized), the permittee must submit an extension request form to the Division at least 10 days prior to the expiration date. 7. Transfer of Permit When responsibility for stormwater discharges at a construction site changes from one individual to another, the permittee shall submit a completed Notice of Transfer and Acceptance of Terms of a Construction General Stormwater Discharge Permit Certification that is signed in accordance with Part I.E.1. of this permit. The Notice of Transfer form is available from the Division and includes: PART I Page 6 Permit No. COR -030000 A. COVERAGE UNDER THIS PERMIT (cont.) a) Permit certification number. b) Name, location, and county for the construction site for which the application is being submitted. c) The current permittee's name, address, telephone number and the status as Federal, State, private, public or other entity. d) The new permittee's name, address and telephone number and the status as Federal, State, private, public or other entity. e) Certification that the new permittee has reviewed the permit and SWMP and accepts responsibility, coverage and liability for the permit. f) Effective date of transfer. If the new responsible party will not complete the transfer form, the permit may be inactivated if the permittee has no legal responsibility, through ownership or contract, for the construction activities at the site. In this case, the new operator would be required to obtain permit coverage separately. 8. Permit Expiration Date Authorization to discharge under this general permit shall expire on June 30, 2007. The Division must evaluate and reissue this general permit at least once every five years and must recertify the applicant's authority to discharge under the general permit at such time. Any permittee desiring continued coverage under the general permit must reapply by March 31, 2007. The Division will determine if the applicant may continue to operate under the terms of the general permit. An individual permit will be required for any facility not reauthorized to discharge under the reissued general permit. 9. Individual Permit Criteria Aside from the activity type, the Division may use other criteria in evaluating whether an individual permit is required instead of this general permit. This information may come from the application, SWMP, or additional information as requested by the Division, and includes, but is not limited to, the following: a) the quality of the receiving waters (i.e., the presence of downstream drinking water intakes or a high quality fishery, or for preservation of high quality water); b) the size of the construction site; c) evidence of noncompliance under a previous permit for the operation; d) the use of chemicals within the stormwater system. In addition, an individual permit may be required when the Division has shown or has reason to suspect that the stormwater discharge may contribute to a violation of a water quality standard. B. CONTENTS OF THE STORMWATER MANAGEMENT PLAN The SWMP shall be prepared in accordance with good engineering, hydrologic and pollution control practices. (The SWMP need not be prepared by a registered engineer.) The main objective of the plan shall be to identify Best Management Practices (BMPs) which when implemented will meet the terms and conditions of this permit (see Part I.C., below). The plan shall identify potential sources of pollution (including sediment) which may reasonably be expected to affect the quality of stormwater discharges associated with construction activity from the facility. In addition, the plan shall describe and ensure the implementation of BMPs which will be used to reduce the pollutants in stormwater discharges associated with construction activity. Construction operations must implement the provisions of the SWMP required under this part as a condition of this permit. The SWMP shall include the following items, at a minimum: B. CONTENTS OF THE STORMWATER MANAGEMENT PLAN (cont.) 1. Site Description Each plan shall provide a description of the following: a) A description of the construction activity. b) The proposed acyueuL.c fw LI JUL en., i sties. PART I Page 7 Permit No. COR -030000 c) Estimates of the total area of the site, and the area of the site that is expected to undergo clearing, excavation or grading. d) An estimate of the runoff coefficient of the site before and after construction activities are completed and any existing data describing the soil, soil erosion potential or the quality of any discharge from the site. e) A description of the existing vegetation at the site and an estimate of the percent vegetative ground cover. f) The location and description of any other potential pollution sources, such as vehicle fueling, storage of fertilizers or chemicals, etc. g) The location and description of any anticipated non-stormwater components of the discharge, such as springs and landscape irrigation return flow. h) The name of the receiving water(s) and the size, type and location of any outfall or, if the discharge is to a municipal separate storm sewer, the name of that system, the location of the storm sewer discharge, and the ultimate receiving water(s). 2. Site Map Each plan shall provide a generalized site reap or maps which indicate: - construction site boundaries - all areas of soil disturbance - areas of cut and fill - areas used for storage of building materials, soils or wastes - location of anydedicated asphalt or concrete batch plants - location of major erosion control facilities or structures - springs, streams, wetlands and other surface waters - boundaries of 100 -year flood plains, if determined. 3. BMPs for Stormwater Pollution Prevention The plan shall include a narrative description of appropriate controls and measures that will be implemented before and during construction activities at the facility. The plan shall clearly describe the relationship between the phases of construction and the implementation and maintenance of controls and measures. For example, which controls will be implemented during each of the following stages of construction: clearing and grubbing necessary for perimeter controls, initiation of perimeter controls, remaining clearing and grubbing, road grading, storm drain installation, final grading, stabilization, and removal of control measures. The description of controls shall address the following minimum components: a) Erosion and Sediment Controls. I) Structural Practices. A description of structural site management practices which will minimize erosion and sediment transport. Practices may include, but are not limited to: straw bales, silt fences, earth dikes, drainage swales, sediment traps, subsurface drains, pipe slope drains, inlet protection, outlet protection, gabions, and temporary or permanent sediment basins. 2) Non -Structural Practices. A description of interim and permanent stabilization practices, including site- specific scheduling of the implementation of the practices. Site plans should ensure that existing vegetation is preserved where possible and that disturbed areas are stabilized. Non-structural practices may include, but are not limited to: temporary seeding, permanent seeding, mulching, geotextiles, sod stabilization, vegetative buffer strips, protection of trees, and preservation of mature vegetation. PART I Page 8 Permit No. COR -030000 B. CONTENTS OF THE STORMWATER MANAGEMENT PLAN (cont.) b) Materials Handling and Spill Prevention. The SWMP shall identify any procedures or significant materials (see definitions at Part I.D.) handled at the site that could contribute pollutants to runoff. These could include sources such as: exposed storage of building materials, fertilizers or chemicals; waste piles; and equipment maintenance or fueling procedures. Areas or procedures where potential spills can occur shall have spill prevention and response procedures identified. Measures to control stormwater pollution from dedicated concrete batch plants or dedicated asphalt batch plants covered by this certification, must be identified in the SWMP. 4. Final Stabilization and Longterm Stormwater Management The plan shall include a description of the measures used to achieve final stabilization and measures to control pollutants in stormwater discharges that will occur after construction operations have been completed. Final stabilization is reached when all soil disturbing activities at the site have been completed, and uniform vegetative cover has been established with a density of at least 70 percent of pre -disturbance levels, or equivalent permanent, physical erosion reduction methods have been employed. For purposes of this permit, establishment of a vegetative cover capable of providing erosion control equivalent to pre- existing conditions at the site can be considered final stabilization. The permittee will be responsible for providing to the Division the documentation to make this comparison. The Division may, after consultation with the permittee and upon good cause, amend the final stabilization criteria for specific operations. 5. Other Controls The plan shall include a description of other measures to control pollutants in stormwater discharges, including plans for waste disposal and limiting off-site soil tracking. 6. Inspection and Maintenance The plan shall include a description of procedures to inspect and maintain in good and effective operating condition the vegetation, erosion and sediment control measures and other protective measures identified in the SWMP. C. TERMS AND CONDITIONS 1. General Limitations The following limitations shall apply to all discharges covered by this permit: a) Stormwater discharges from construction activities shall not cause or threaten to cause pollution, contamination or degradation of State waters. b) Concrete wash water shall not be discharged to state waters or to storm sewer systems. c) Bulk storage structures for petroleum products and other chemicals shall have adequate protection so as to contain all spills and prevent any spilled material from entering State waters. d) No chemicals are to be added to the discharge unless permission for the use of a specific chemical is granted by the Division. In granting the use of such chemicals, special conditions and monitoring may be addressed by separate letter. e) The Division reserves the right to require sampling and testing, on a case-by-case basis, in the event that there is reason to suspect that compliance with the SWMP is a problem, or to measure the effectiveness of the BMPs in removing pollutants in the effluent. Such monitoring may include Whole Effluent Toxicity testing. C. TERMS AND CONDITIONS (cont.) PART I Page 9 Permit No. COR -030000 f) All wastes composed of building materials must be removed from the site for disposal in licensed disposal facilities. No building material wastes or unused building materials shall be buried, dumped, or discharged at the site. g) Off-site vehicle tr.cling of bedinx nw st,a11 be-nwunuzcd h) All dischargers must comply with the lawful requirements of municipalities, counties, drainage districts and other local agencies regarding any discharges of stormwater to storm drain systems or other water courses under their jurisdiction, including applicable requirements in municipal stormwater management programs developed to comply with CDPS permits. Dischargers must comply with local stormwater management requirements, policies or guidelines including erosion and sediment control. 2. Prohibition of Non-Stormwater Discharges a) Except as provided in paragraph b, below, all discharges covered by this permit shall be composed entirely of stormwater. Discharges of material other than stormwater must be addressed in a separate CDPS permit issued for that discharge. b) Discharges from the following sources that are combined with stormwater discharges associated with construction activity may be authorized by this permit, provided that the non-stormwater component of the discharge is identified in the SWMP (see Part I.B.1.g of this permit): - fire fighting activities - landscape irrigation return flow - springs 3. Releases in Excess of Reportable Quantities This permit does not relieve the permittee of the reporting requirements of 40 CFR 110, 40 CFR 117 or 40 CFR 302. Any discharge of hazardous material must be handled in accordance with the Division's Notification Requirements (see Part I1.A.3 of the permit). 4. Stormwater Management Plans Prior to commencement of construction, the stormwater management plan (SWMP) shall be implemented for the construction site covered by this permit. a) Signatory Requirements: The plan shall be signed in accordance with Part I.E.1., with one retained on site. b) SWMP Review/Changes: The permittee shall amend the plan whenever there is a significant change in design, construction, operation, or maintenance, which has a significant effect on the potential for the discharge of - pollutants to the waters of the State, or if the SWMP proves to be ineffective in achieving the general objectives of controlling pollutants in stormwater discharges associated with construction activity. 5. Inspections a) Active Sites - For sites where construction has not been completed, the permittee shall make a thorough inspection of their stormwater management system at least every 14 days and after any precipitation or snowmelt event that causes surface erosion. 1) The construction site perimeter, disturbed areas and areas used for material storage that are exposed to precipitation shall be inspected for evidence of, or the potential for, pollutants entering the drainage system. Erosion and sediment control measures identified in the SWMP shall be observed to ensure that they are operating correctly. PART Page 10 Permit No. COR -030000 C. TERMS AND CONDITIONS (cont.) 2) Based on the results of the inspection, the description of potential pollutant sources, and the pollution prevention and control measures that are identified in the SWMP shall be revised and modified as appropriate as soon as practicable after such inspection. Modifications to control measures shall be implemented in a timely manner, but in no case more than 7 calendar days after the inspection. 3) The operator shall keep a record of inspections. Any incidence of non-compliance, such as uncontrolled releases of mud or muddy water or measurable quantities of sediment found off the site, shall be recorded with a brief explanation as to the measures taken to prevent future violations, as well as any measure taken to clean up the sediment that has left the site. After adequate measures have been taken to correct any problems, or where a report does not identify any incidents of non-compliance, the report shall contain a signed certification indicating the site is in compliance. This record shall be made available to the Division upon request. b) Completed Sites - For sites where all construction activities are completed but final stabilization has not been achieved due to a vegetative cover that has been planted but has not become established, the permittee shall make a thorough inspection of their stormwater management system at least once every month. When site conditions make this schedule impractical, permittees may petition the Division to grant an alternate inspection schedule. These inspections must be conducted in accordance with paragraphs I), 2), and 3) of Part I.C.5.a. above. c) Winter Conditions - Inspections, as described above in a) and b), will not be required at sites where snow cover exists over the entire site for an extended period, and melting conditions do not exist. This exemption is applicable only during the period where melting conditions do not exist. Regular inspections, as described above, are required at all other times. 6. Reporting No regular reporting requirements are included in this permit; however, the Division reserves the right to request that a copy of the inspection reports be submitted. 7. SWMP Submittal Upon Request Upon request, the permittee shall submit a copy of the SWMP to the Division, EPA or any local agency in charge of approving sediment and erosion plans, grading plans or stormwater management plans. All SWMPs required under this permit are considered reports that shall be available to the public under Section 308(b) of the CWA. The owner or operator of a facility with stormwater discharges covered by this permit shall make plans available to members of the public upon request, unless the SWMP has been submitted to the Division. However, the permittee may claim any portion of a SWMP as confidential in accordance with 40 CFR Part 2. D. ADDITIONAL DEFINITIONS For the purposes of this permit: 1. BAT and BCT: (Best Available Technology and Best Conventional Technology) Technology based federal water quality requirements covered under 40 CFR. subchapter N. 2. Best management practices (BMPs): schedules of activities, prohibitions of practices, maintenance procedures, and other management practices to prevent or reduce the pollution of waters of the State. BMPs also include treatment requirements, operating procedures, and practices to control site runoff, spillage or leaks, waste disposal, or drainage from material storage. 3. Dedicated asphalt plants and concrete plants: portable asphalt plants and concrete plants that are located on or adjacent to a construction site and that provide materials only to that specific construction site. PARTI Page 11 Permit No. COR -030000 D. ADDITIONAL DEFINITIONS (cont.) 4. Final stabilization: when all soil disturbing activities at the site have been completed, and uniform vegetative cover has been established with a density of at least 70 percent of pre -disturbance levels, or equivalent permanent, physical erosion reduction methods have been employed. For purposes of this permit, establishment of a vegetative cover capable of providing erosion control equivalent to pre-existing conditions at the site will be considered final stabilization. 5. Municipal storm sewer system: a conveyance or system of conveyances (including: roads with drainage systems, municipal streets, catch basins, curbs, gutters, ditches, man-made channels, or storm drains), owned or operated by a State, city, town, county, district, or other public body (created by state law), having jurisdiction over disposal of sewage, industrial waste, stormwater, or other wastes; designed or used for collecting or conveying stormwater. 6. Operator: the individual who has day-to-day supervision and control of activities occurring at the construction site. This can be the owner, the developer, the general contractor or the agent of one of these parties, in some circumstances. It is anticipated that at different phases of a construction project, different types of parties may satisfy the definition of 'operator' and that the permit may be transferred as the roles change. 7. Outfall: a point source at the point where stormwater leaves the construction site and discharges to a receiving water or a stormwater collection system. 8. Part of a larger common plan of development or sale: a contiguous area where multiple separate and distinct construction activities may be taking place at different times on different schedules under one plan. 9. Point source: any discernible, confined and discrete conveyance from which pollutants are or may be discharged. Point source discharges of stormwater result from structures which increase the imperviousness of the ground which acts to collect runoff, with runoff being conveyed along the resulting drainage or grading pattern. 10. Process water: any water which during manufacturing or processing, comes into contact with or results from the production of any raw material, intermediate product, finished product, by product or waste product. This definition includes mine drainage. 11. Receiving Water: any water of the State of Colorado into which stormwater related to construction activities discharges. 12. Runoff coefficient: the fraction of total rainfall that will appear as runoff. 13. Significant Materials include but are not limited to: raw materials; fuels; materials such as metallic products; hazardous substances designated under section 101(14) of CERCLA; any chemical the facility is required to report pursuant to section 313 of title III of SARA; fertilizers; pesticides; and waste products such as ashes, slag and sludge that have the potential to be released with stormwater discharge. 14. Stormwater: precipitation -induced surface runoff. 15. Waters of the state of Colorado: any and all surface waters that are contained in or flow in or through the state of Colorado. This definition includes all water courses, even if they are usually dry. E. GENERAL REQUIREMENTS I. Signatory Requirements a) All reports required for submittal shall be signed and certified for accuracy by the permittee in accordance with the following criteria: 1) In the case of corporations, by a principal executive officer of at least the level of vice-president or his or her duly authorized representative, if such representative is responsible for the overall operation of the facility from which the discharge described in the form originates; 2) In the case of a partnership, by a general partner; PART I Page 12 Permit No. COR -030000 E. GENERAL REQUIREMENTS (cont.) 3) In the case of a sole proprietorship, by the proprietor; 4) In the case of a municipal, state, or other public facility, by either a principal executive officer, ranking elected official, or other duly authorized employee. b) Changes to authorization. If an authorization under paragraph a) of this section is no longer accurate because a different individual or position has responsibility for the overall operation of the facility, a new authorization satisfying the requirements of paragraph a) of this section must be submitted to the Division, prior to or together with any reports, information, or applications to be signed by an authorized representative. c) Certification. Any person signing a document under paragraph a) of this section shall make the following certification: "I certify under penalty of law that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gather and evaluate the information submitted. Based on my inquiry of the person or persons who manage the system, or those persons directly responsible for gathering the information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations." 2. Retention of Records a) The permittee shall retain copies of the SWMP and all reports required by this pemsit and records of all data used to complete the application to be covered by this permit, for a period of at least three years from the date that the site is fmally stabilized. b) The permittee shall retain a copy of the SWMP required by this permit at the construction site from the date of project initiation to the date of final stabilization, unless another location, specified by the pennittee, is approved by the Division. PART II A. MANAGEMENT REQUIREMENTS 1. Change in Discharge The permittee shall inform the Division (Permits Unit) in writing of any intent to significantly change activities from those indicated in the permit application (this does not include changes to the SWMP). Upon request, the permittee shall furnish the Division with such plans and specifications which the Division deems reasonably necessary to evaluate the effect on the discharge and receiving stream The SWMP shall be updated within 30 days of the changes. The permittee shall submit this notice to the Division within two weeks after making a determination to perform the type of activity referred to in the preceding paragraph. Any discharge to the waters of the State from a point source other than specifically authorized by this permit is prohibited. 2. Special Notifications - Definitions a) Spill: An unintentional release of solid or liquid material which may cause pollution of state waters. b) Upset: An exceptional incident in which there is unintentional and temporary noncompliance with permit effluent limitations because of factors beyond the reasonable control of the pennittee. An upset does not include noncompliance to the extent caused by operational error, improperly designed treatment facilities, inadequate treatment facilities, lack of preventative maintenance, or careless or improper operation. A. MANAGEMENT REQUIREMENTS (cont.) PART II Page 13 Permit No. COR -030000 3. Noncompliance Notification a) If, for any reason, the permittee does not comply with or will be unable to comply with any permit limitations, standards or permit requirements specified in this permit, the permittee shall, at a minimum, provide the Water Quality CouuulDivisiuu and LPA with ll,c following i,Surmmat om 1) A description of the discharge and cause of noncompliance; 2) The period of noncompliance, including exact dates and times and/or the anticipated time when the discharge will return to compliance; and 3) Steps being taken to reduce, eliminate, and prevent recurrence of the noncomplying discharge. b) The permittee shall report the following instances of noncompliance orally within twentv-four (24) hours from the time the permittee becomes aware of the noncompliance, and shall mail to the Division a written report within five (5) days after becoming aware of the noncompliance (unless otherwise specified by the Division): 1) Any instance of noncompliance which may endanger health or the environment; 2) Any spill or discharge of oil or other substance which may cause pollution of the waters of the state. c) The permittee shall report all other instances of non-compliance to the Division within 30 days. The reports shall contain the information listed in sub -paragraph (a) of this section. 4. Submission of Incorrect or Incomplete Information Where the permittee failed to submit any relevant facts in a pemiit application, or submitted incorrect information in a permit application or report to the Division, the permittee shall promptly submit the relevant application information which was not submitted or any additional information needed to correct any erroneous information previously submitted. 5. Bypass The bypass of treatment facilities is generally prohibited. 6. Upsets a) Effect of an Upset An upset constitutes an affirmative defense to an action brought for noncompliance with permit limitations and requirements if the requirements of paragraph b of this section are met. (No determination made during administrative review of claims that noncompliance was caused by upset, and before an action for noncompliance, is final administrative action subject to judicial review.) b) Conditions Necessary for a Demonstration of Upset A permittee who wishes to establish the affirmative defense of upset shall demonstrate through properly signed contemporaneous operating Togs, or other relevant evidence that: 1) An upset occurred and that the permittee can identify the specific cause(s) of the upset; 2) The permitted facility was at the time being properly operated; 3) The permittee submitted notice of the upset as required in Part II.A.3. of this permit (24-hour notice); and PART II Page 14 Permit No. COR -030000 A. MANAGEMENT REQUIREMENTS (cont.) 4) The permittee complied with any remedial measures required under Section 122.7(d) of the federal regulations. c) Burden of Proof In any enforcement proceeding the permittee seeking to establish the occurrence of an upset has the burden of proof. 7. Removed Substances Solids, sludges, or other pollutants removed in the course of treatment or control of wastewaters shall be properly disposed of in a manner such as to prevent any pollutant from such materials from entering waters of the State. 8. Minimization of Adverse Impact The permittee shall take all reasonable steps to minimize any adverse impact to waters of the State resulting from noncompliance with any effluent limitations specified in this permit, including such accelerated or additional monitoring as necessary to determine the nature and impact of the noncomplying discharge. 9. Reduction, Loss, or Failure of Treatment Facility The permittee has the duty to halt or reduce any activity if necessary to maintain compliance with the permit requirements. Upon reduction, loss, or failure of the treatment facility, the permittee shall, to the extent necessary to maintain compliance with its permit, control production, or all discharges, or both until the facility is restored or an alternative method of treatment is provided. It shall not be a defense for a permittee in an enforcement action that it would be necessary to halt or reduce the permitted activity in order to maintain compliance with the conditions of this permit. 10. Proper Operation and Maintenance The permittee shall at all times properly operate and maintain all facilities and systems of treatment and control (and related appurtenances) which are installed or used by the permittee to achieve compliance with the conditions of this permit. Proper operation and maintenance includes effective performance, adequate funding, adequate operator staffing and training, and adequate laboratory and process controls, including appropriate quality assurance procedures. This provision requires the operation of back-up or auxiliary facilities or similar systems only when necessary to achieve compliance with the conditions of the permit. B. RESPONSIBILITIES 1. Inspections and Right to Entry The permittee shall allow the Director of the State Water Quality Control Division, the EPA Regional Administrator, and/or their authorized representative, upon the presentation of credentials: a) To enter upon the permittee's premises where a regulated facility or activity is located or in which any records are required to be kept under the terms and conditions of this permit; b) At reasonable times to have access to and copy any records required to be kept under the terms and conditions of this permit and to inspect any monitoring equipment or monitoring method required in the permit; and c) To enter upon the permittee's premises to investigate, within reason, any actual, suspected, or potential source of water pollution, or any violation of the Colorado Water Quality Control Act. The investigation may include, but is not limited to, the following: sampling of any discharge and/or process waters, the taking of photographs, interviewing permittee staff on alleged violations, and access to any and all facilities or areas within the permittee's premises that may have any effect on the discharge, permit, or alleged violation. B. RESPONSIBILITIES (cont.) 2. Duty to Provide Information PART II Page 15 Permit No. COR -030000 The permittee shall furnish to the Division, within a reasonable time, any information which the Division may request to determine whether cause exists for modifying, revoking and reissuing, or inactivating coverage under this permit, or to determine cumptiarae wain dus pcwi,ut The yeu,uttcc shall also fwmsh KJ the D,.,,,un, r,pun wp,cs of n cods required to be kept by this permit. 3. Transfer of Ownership or Control Certification under this permit may be transferred to a new permittee if: a) The current permittee notifies the Division in writing when the transfer is desired; and b) The notice includes a written agreement between the existing and new permittees containing a specific date for transfer of permit responsibility, coverage and liability between them; and c) The current permittee has met all fee requirements of the State Discharge Permit System Regulations, Section 61.15. 4. Modification, Suspension, or Revocation of Permit By Division All permit modification, inactivation or revocation and reissuance actions shall be subject to the requirements of the State Discharge Permit System Regulations, Sections 61.5(2), 61.5(3), 61.7 and 61.15, 5 C.C.R. 1002-61, except for minor modifications. a) This permit, and certification under this permit, may be modified, suspended, or revoked in whole or in part during its tenn for reasons determined by the Division including, but not limited to, the following: I) Violation of any terms or conditions of the permit; 2) Obtaining a permit by misrepresentation or failing to disclose any fact which is material to the granting or denial of a permit or to the establishment of terms or conditions of the permit; 3) Materially false or inaccurate statements or information in the application for the permit; 4) Promulgation of toxic effluent standards or prohibitions (including any schedule of compliance specified in such effluent standard or prohibition) which are established under Section 307 of the Clean Water Act, where such a toxic pollutant is present in the discharge and such standard or prohibition is more stringent than any limitation for such pollutant in this permit. b) This permit, or certification under this permit, may be modified in whole or in part due to a change in any condition that requires either a temporary or permanent reduction or elimination of the permitted discharge, such as: 1) Promulgation of Water Quality Standards applicable to waters affected by the permitted discharge; or 2) Effluent limitations or other requirements applicable pursuant to the State Act or federal requirements; or 3) Control regulations promulgated; or 4) Data submitted pursuant to Part I.B or Part LC.1 indicates a potential for violation of adopted Water Quality Standards or stream classifications. PART II Page 16 Pemut No. COR -030000 B. RESPONSIBILITIES (cont.) c) This permit, or certification under this permit, may be modified in whole or in part to include new effluent limitations and other appropriate conditions where data submitted pursuant to Part I indicates that such effluent limitations and conditions are necessary to ensure compliance with applicable water quality standards and protection of classified uses. d) At the request of the permittee, the Division may modify or inactivate certification under this permit if the following conditions are met: 1) In the case of inactivation, the permittee notifies the Division of its intent to inactivate the certification, and certifies that the site has been finally stabilized; 2) In the case of inactivation, the permittee has ceased any and all discharges to state waters and demonstrates to the Division there is no probability of further uncontrolled discharge(s) which may affect waters of the State. 3) The Division finds that the pemtittee has shown reasonable grounds consistent with the Federal and State statutes and regulations for such modification, amendment or inactivation; 4) Fee requirements of Section 61.15 of State Discharge Permit System Regulations have been met; and 5) Requirements of public notice have been met. For small construction sites covered by a Qualifying Local Program, coverage under this permit is automatically terminated when a site has been finally stabilized. 5. Permit Violations Failure to comply with any terms and/or conditions of this permit shall be a violation of this permit. Dischargers of stormwater associated with industrial activity, as defined in the EPA Stormwater Regulation (40 CFR 122.26(b)(14), which do not obtain coverage under this or other Colorado general permits, or under an individual CDPS permit regulating industrial stormwater, will be in violation of the federal Clean Water Act and the Colorado Water Quality Control Act, 25-8-101. Failure to comply with CDPS permit requirements will also constitute a violation. Civil penalties for such violations may be up to $10,000 per day, and criminal pollution of state waters is punishable by fines of up to $25,000 per day. 6. Legal Responsibilities The issuance of this permit does not convey any property or water rights in either real or personal property, or stream flows, or any exclusive privileges, nor does it authorize any injury to private property or any invasion of personal rights, nor any infringement of Federal, State or local laws or regulations. Nothing in this permit shall be construed to preclude the institution of any legal action or relieve the permittee from any responsibilities, liabilities, or penalties to which the permittee is or may be subject to under Section 311 (Oil and Hazardous Substance Liability) of the Clean Water Act. 7. Severability The provisions of this permit are severable. If any provisions of this permit, or the application of any provision of this permit to any circumstance, is held invalid, the application of such provision to other circumstances and the application of the remainder of this permit shall not be affected. PART II Page 17 Permit No. COR -030000 B. RESPONSIBILITIES (cont.) 8. Renewal Application If the permittee desires to continue to discharge, a permit renewal application shall be submitted at least ninety (90) days before this permit expires. If the permittee anticipates that there will be no discharge after the expiration date of this permit, the Division should be ptuu.ptly nun frcd aulhat it Lnu U611atc the t.crl.fiLatwu u. acn ,v.d. Pmt II.B.4.d. 9. Confidentiality Except for data detemrined to be confidential under Section 308 of the Federal Clean Water Act and Regulations for the State Discharge Penult System 61.5(4), all reports prepared in accordance with the terms of this permit shall be available for public inspection at the offices of the Division. The permittee must state what is confidential at the time of submittal. Any information relating to any secret process, method of manufacture or production, or sales or marketing data which has been declared confidential by the permittee, and which may be acquired, ascertained, or discovered, whether in any sampling investigation, emergency investigation, or otherwise, shall not be publicly disclosed by any member, officer, or employee of the Commission or the Division, but shall be kept confidential. Any person seeking to invoke the protection of this section shall bear the burden of proving its applicability. This section shall never be interpreted as preventing full disclosure of effluent data. 10. Fees The permittee is required to submit payment of an annual fee as set forth in the Water Quality Control Act. Failure to submit the required fee when due and payable is a violation of the permit and will result in enforcement action pursuant to Section 25-8-601 et. seq., C.R.S. 1973 as amended. _ _ 11. Requiring an Individual CDPS Permit The Director may require any owner or operator covered under this permit to apply for and obtain an individual CDPS permit if: a) The discharger is not in compliance with the conditions of this general permit; b) Conditions or standards have changed so that the discharge no longer qualifies for a general permit; or c) Data become available which indicate water quality standards may be violated. The owner or operator must be notified in writing that an application for an individual CDPS permit is required. When an individual CDPS permit is issued to an owner or operator otherwise covered under this General Permit, the applicability of the general permit to that owner or operator is automatically inactivated upon the effective date of the individual CDPS permit. COLORADO DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT Water Quality Control Division WQCD-P-B2 '0 Cherry Creek Drive South —ewer, Colorado 80246-1530 RATIONALE STORMWATER DISCHARGES ASSOCIATED WITH NJIKUWIUN AUIIVII GENERAL PERMIT IN COLORADO SECOND RENEWAL COLORADO DISCHARGE PERMIT NUMBER COR -030000 CONTENTS PA GE I Introduction 1 II. Background 2 111 Stormwater Discharges Associated with Construction Activity 3 IV. Coverage Under this Permit 4 V Application and Certification 4 VI. Qualifying Local Programs 4 VH. Terms and Conditions of Permit 5 VII/. Changes Made After Public Notice 7 I. INTRODUCTION This permit is for the regulation ofstonnwater runoff from construction activities. The term "construction activity" includes clearing, grading and excavation operations. "Stormwater" is precipitation-inducedsutface runoff This Rationale will explain the background of the Stormwater program, activities which are covered under this permit, how to apply for coverage under this permit, and the requirements of this permit. The forms discussed in the Rationale and Permit are available on the Division's website at: httpilhvww.cdphe.state.co.us/wq/permitsunit/wqcdpmt.html A. Changes in this General Permit Several notable changes from the previous General Permit for Construction Activities have been incorporated into this permit. Most of the changes are related to the Phase Ii revision to the stormwater regulation in the Colorado Discharge Permit System Regulations (SCCR 1002-61), effective March 2, 2001. Significant changes are listed below: Permit coverage is now required for construction sites that disturb 1 to 5 acres (i.e., small construction activities). Allowances have been made for small construction activities to comply with the requirements of a Division -approved Qualifying Local Program (refer to section VI below for a discussion of Qualifying Local Programs) in place of many specific requirements in the Permit, including requirements to submit an application, inactivation notice, and fees to the Division. Refer to PartLA.3 of the Permit and section VILA of the Rationale for more details. 2. The requirements to submit with the application the Township, Range, section and quarter section ofa site and a list of any other environmental permits for the site have been removed. 3. Inactivation requirements have been changed to allow small construction activities that submit applications indicating a completion date 12 months or less from the start of construction activity to be authorized for a predetermined period from 3 to 12 months. The permit certification will include the automatic expiration date for permit coverage. This expiration date will be in place of the requirement to submit an Inactivation Notice. If permit coverage beyond the expiration date is needed (i.e., the site has not been finally stabilized), the permittee must submit an extension request form to the Division at least 10 days prior to the expiration. COLORADO DEPA RTMENT OF PUBLIC HEALTH AND ENVIRONMENT, Water Quality Control Division Rationale - Page 2. Permit No. COR -030000 I INTRODUCTION (cont.) 4. The Rationale discussion on the Exemptions for Small Municipalities (Section III.B) has been changed to include the March 10, 2003 deadline for permit coverage for municipally -owned industries. This did not involve any changes to the permit. II. BACKGROUND As required under the Clean Water Act amendments of 1987, the Environmental Protection Agency (EPA) has established a framework for regulating municipal and industrial stormwater discharges. This framework is under the National Pollutant Discharge Elimination System (NPDES) program (Note: The Colorado program is referred to as the Colorado Discharge Permit System, or CDPS, instead of NPDES). The Water Quality Control Division ("the Division') has stormwater regulations (SCCR 1002-61) in place. These regulations require specific types of industrial facilities that discharge stormwater associated with industrial activity (industrial stormwater), to obtain a CDPS permit for such discharge. The regulations specifically include construction activities that disturb one acre of land or more as industrial facilities. Construction activities that are part of a larger common plan of development which disturb one acre or more over a period of time are also included. A. General Permits The Water Quality Control Division ("the Division') has determined that the use of general permits is the appropriate procedure for handling the thousands of industrial stormwater applications within the State. B. Permit Requirements This permit does not require submission of effluent monitoring data in the permit application or in the permit itself. It is believed that a fully implemented Stormwater Management Plan (SWMP) should be sufficient to control water quality impacts. The permit requires dischargers to control and eliminate the sources of pollutants in stormwater through the development and implementation ofa SWMP. The plan must include Best Management Practices (BMPs), which will include pollution prevention and source reduction measures. This will constitute .BAT and BCT and should achieve compliance with water quality standards. The narrative permit requirements include prohibitions against discharges of non-stormwater (e.g., process water). Refer to Part LC.2 of the permit. In addition, as a condition of this permit, the permittee is required to pay the annual fee as described in the Water Quality Control Act. Failure to submit the required fee when due and payable is a violation of the permit and will result in enforcement action as discussed below. Permittees will be billed for the initial permit fee within a few weeks ofpermit issuance. Some construction activities may be required to comply with a Qualifying Local Program in place of meeting several of the specific requirements in this permit. Sites covered by a Qualifying Local Program may not be required to submit an application for coverage or a notice of inactivation and may not be required to pay the annual fee. Refer to Section VILA of the Rationale forfitrther information. C. Violations/Penalties Dischargers of stormwater associated with industrial activity, as defined in the Regulations for the State Discharge Permit System (5CCR 1002-61), which do not obtain coverage under this or other Colorado general permits, or under an individual CDPS permit regulating industrial stormwater, will be in violation of the Federal Clean Water Act and the Colorado Water Quality Control Act, 25-8-101. For facilities covered under a CDPS permit, failure to comply with any CDPS permit requirement constitutes a violation. Civil penalties for violations of the Act or CDPS permit requirements may be up to $10,000 per day. Criminal pollution of state waters is punishable by fines of up to 325,000 per day. COLORADO DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT, Water Quality Control Division Rationale - Page 3. Permit No. COR -030000 111. STORMWATER DISCHARGES ASSOCIATED WITH CONSTRUCTION ACTIVITY The Stormwater regulations require Mw stormwater discharges associated with certain industrial activities be covered under the permit program. Construction activity that disturbs one acre or more during the life of the project is specifically included in the listed industrial activities. A, Construction Activity Construction activity includes clearing, grading and excavation activities. Construction does not include routine maintenance performed by public agencies, or their agents to maintain original line and grade, hydraulic capacity, or original purpose of the facility. Definitions of additional terms can be found in Part ID of the Permit. Stormwater discharges from construction activity require permit coverage, except for operations that result in the disturbance of less than one acre of total land area which are not part ofa larger common plan of development or sale. A larger common plan of development or sale is a contiguous area where multiple separate and distinct construction activities may be taking place at different times on different schedules under one plan. B. Types ofActivities Covered This permit is intended to cover most new or existing discharges composed entirely of stonnwater from construction activities that are required by State regulation to obtain a permit. This includes stormwater discharges associated with areas that are dedicated to producing earthen materials, such as soils, sand, and gravel, for use at a single construction site. These areas may be located at the construction site or at some other location. This permit does not authorize the discharge of mine water or process waterfrom such areas. This permit also includes stormwater discharges associated with dedicated asphalt plants and concrete plants located at the construction sites. Types ofActivities NOT Covered This permit does not cover stonnwater discharged from construction sites that is mixed with stormwater from other types of industrial activities, or process water of any kind. Other types of industrial activities that require stormwater discharge permits pursuant to different sections of the regulations (Regulation 5 CCR 1002-61, Section 61.2(e)(iii)(A-I, K)1, are not covered by this permit. This permit also does not cover the discharge of process water. If the construction activity encounters groundwater, a Construction Dewatering Discharge Permit (Permit Number COG -070000) must also be obtained in order to discharge this groundwater from the excavation site. An application for this permit can be obtained from the Division at the address listed in Part LA.4.a of the Permit. D. Exemptions for Small Municipalities The Intermodal Surface Transportation Efficiency Act of 1991 (Section 1068(c)) added an exemption to the stormwater regulations for municipalities with less than 100, 000 population. The term "municipality" includes cities, towns, counties, special districts or any entity created by or pursuant to State law. Stonnwater discharges associated with construction activity for facilities or sites that are owned or operated by a small municipality are not required to apply for or obtain a stormwater permit until March 10, 2003. (Note: This exemption does not apply to other, privately owned construction sites within the same small municipality) COLORADO DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT, Water Quality Control Division Rationale - Page 4. Permit No. COR -030000 IV. COVERAGE UNDER THIS GENERAL PERMIT Under this general permit, operators of stormwater discharges associated with construction activity may be granted authorization to discharge stormwater into waters of the State of Colorado. This includes stormwater discharges associated with industrial activity from areas that are dedicated to producing earthen materials, such as soils, sand and gravel, for use at a single construction site, and dedicated asphalt plants and dedicated concrete plants. This permit does not pre-empt or supersede the authority of local agencies to prohibit, restrict or control discharges of stormwater to storm drain systems or other water courses within their jurisdiction. Authorization to discharge under the permit requires submittal ofa completed application form and a certification that the SWMP is complete, unless the site is covered by a Qualifying Local Program. Upon receipt of all required information, the Division may allow or disallow coverage under the general permit. V. APPLICATION AND CERTIFICATION At least ten days prior to the commencement of construction activities (i.e.: the initial disturbance of soils associated with clearing, grading, excavation activities, installation of structural BMPS, or other activities), the operator of the construction site shall submit an original completed application which includes the signed certification that the SWMP is complete. In order to avoid confusion during processing, original signatures are required for the application to be considered complete. For small construction sites only, if the site is covered by a Qualifying Local Program (see below), submittal of an application is not required. For the purpose of this permit, the "operator" is the person who has day-to-day control over the project. This can be the owner, the developer, the general contractor or the agent of one of these parties, in some circumstances. At different times of a construction project, different types of parties may satisfy the definition of 'operator' and the certification may be transferred as roles change. . (Note - Under the Federal regulations, this application process is referred to as a Notice of Intent, or NOI. For internal consistency with its current program, the Division will continue to use the term "application.') An outline of the permit application requirements is found in the permit at Part LA.4.b. If this general permit is applicable, then a certification will be developed and the applicant will be certified under this general permit. VI. QUALIFYING LOCAL PROGRAMS For stormwater discharges associated with small construction activity (i.e., one to five acre sites), the permit includes conditions that incorporate approved qualfing local erosion and sediment control program (Qualifying Local Program) requirements by reference. A Qualifying Local Program is a municipal stormwater program for stormwater discharges associated with small construction activity that has been formally approved by the Division. The requirements for Qualifying Local Programs are outlined in Part 61.8(12) of the Colorado Discharger Permit System Regulations (also see the Division's "Qualifying Local Programs for Small Construction Sites - Application Guidance'). Such programs must impose requirements to protect water quality that are at least as strict as those required in this permit. A. Approval Termination: A Qualifying Local Program may be terminated by either the Division or the municipality. Upon termination of Division approval ofa Qualifying Local Program, any small construction activity required to obtain permit coverage under Section 61.3(2)(h) of the State Discharge Permit System Regulations shall submit an application form as provided by the Division, with a certification that the Stormwater Management Plan (SWMP) is complete as required by Part 1.A.4 of the Permit, within 30 days. B Approval Expiration: Division approval ofa Qualifying Local Program will expire with this general permit on June 30, 2007. Any municipality desiring to continue Division approval of their program must reapply by March 31, 2007. The Division will determine if the program may continue as a approved Qualtfring Local Program. COLORADO DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT Water Quality Control Division Rationale - Page 5. Permit No. COR -030000 VIL TERMS AND CONDITIONS OF PERMIT A. Coverage under a Qualifying Local Program — For Small Construction Sites Only For small construction sites (disturbing less than 5 acres) covered under a Qualifying Local Program (see Section VI above), nnly rertnin permit requirements apply as outlined below. The local program must have been formally designated by the Division to qualify. Most municipalities have some type of local program and may require permits and fees. However, simply having a program in place does not necessarily mean that it is a qualifying program and that a State permit is not required. The local municipality will be responsible for nothing operators and/or owners that they are covered by a Qualifying Local Program. A list of municipalities with Qualifying Local Programs is also available at http://www.cdphe.state.co.us/wq/PermitsUnit/wgcdpmt.html. The Division reserves the right to require any owner or operator within the jurisdiction of a Qualifying Local Program covered under this permit to apply for and obtain coverage under the full requirements of this permit. 1. Permit Coverage: If a construction site is within the jurisdiction ofa Qualing Local Program, the operator of the construction activity is authorized to discharge stormwater associated with small construction activity under this general permit without the submittal of an application to the Division. The permittee also is not required to submit an inactivation notice or payment of an annual fee to the Division. 2. Permit Terms and Conditions: The permittee covered by a Qualifying Local Program must comply with the requirements of that Qualifying Local Program . In addition, the following permit sections are applicable: t. I.A.1, i.A.2, and 1,4.3: Authorization to discharge and discussion of coverage under the permit. it I.C.1: General limitations that must be met in addition to local requirements. LC.2, L.C.3: Prohibition of non-stormwater discharges unless addressed in a separate CDPS permit, and requirements related to releases of reportable quantities. iv. I.D.• Additional definitions. v. Part 1I (except for Parts HA. I, II.B.3, 113.8, and II.B10): Specifically includes, but is not limited to, provisions applicable in the case of noncompliance with permit requirement, and requirements to provide information and access. B. Stormwater Management Plans (SWMPs) Prior to commencement of construction, a stormwater management plan (SWMP) shall be developed and implemented for each facility covered by this permit. A certification that the SWMP is complete must be submitted with the permit application. The SWMP shall identift potential sources of pollution (Including sediment) which may reasonably be expected to affect the quality ofstormwater discharges associated with construction activityfrom the facility. In addition, the plan shall describe the best management practice (BMPs) which will be used to reduce the pollutants in stormwater discharges from the construction site. Facilities must implement the provisions of their SWMP as a condition of this permit. The SWMP shall include the following items: 1. Site Description 2. Site Map 3. BMPs for StormwaterPollution Prevention 4. Longterm Stormwater Management 5. Other Controls 6. Inspection and Maintenance 7. Signatory Requirements and Availability 8. SWMP Review/Changes (See Part I.B. of the permit for a more detailed description of SWMP requirements.) COLORADO DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT, Water Quality Control Division Rationale - Page 6. Permit No. COR -030000 VII TERMS AND CONDITIONS OF PERMIT (cont.) C. Monitorinv Sampling and testing of stormwater for specific parameters is not required on a routine basis under this permit. However, the Division reserves the right to require sampling and testing on a case-by-case basis, in the event that there is reason to suspect that compliance with the SWMP is a problem, or to measure the effectiveness of the BMPs in removing pollutants in the effluent. D. Facility Inspections Active construction sites must inspect their stormwater management controls at least every 14 days and after any precipitation or snowmen event that causes surface erosion. At sites where construction has been completed but a vegetative cover has not been established, these inspections must occur at least once per month. At sites where winter conditions exist, inspections are not required during the period that the winter conditions exist. For all of these inspections, records must be kept on file. Refer to the permit at Part I.C5 for detailed requirements of these inspections. E. Revision of SWMP Based on the results of the inspections (see D. above), the description of potential pollutant sources and the pollution prevention and control measures, identified in the SWMP, and the control measures themselves, shall be revised and modified as appropriate as soon as practicable after such inspection. Modification of control measures shall be implemented in a timely manner, but in no case more than 7 calendar days after the inspection. F. Reporting; The inspection record shall be made available to the Division upon request. Regular submittal of an annual report is not required in this permit. G. Annual Fee The permittee is required to submit payment of an annual fee as set forth in the Water Quality Control Act. Permittees will be billed for the initial permit fee within a few weeks of permit issuance and then annually, based on a July 1 through June 30 billing cycle. For small construction activities, if application was made for coverage with a completion date 12 months or less from the start of construction activity, a fee will be assessed based on the estimated number of calendar quarters the site is active. Projects going beyond that time will be billed the standard annual fee. H. Inactivation Notice When a site has been finally stabilized in accordance with the SWMP, the operator of the facility shall submit an Inactivation Notice that is signed in accordance with Part I.E.1 of the permit. The content of the Inactivation Notice is described in Part I.A.6 of the permit. A copy of the Inactivation Notice form will be mailed to the permittee along with the permit certification. Additional copies are available from the Division. An exception to the requirement to submit an inactivation has been included in the renewed permit for Small Construction Sites that will be finally stabilized within 12 months of the beginning of construction activities. In such cases, the permit certification will indicate the automatic expiration date. If permit coverage is needed beyond that date, an extension requestform must be submitted to the Division at least 10 days prior to the expiration date. COLORADO DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT, Water Quality Control Division Rationale - Page 7. Permit No. COR -030000 VII. TERMS AND CONDITIONS OF PERMIT (cont.) I Transfer of Permit When responsibility for stormwater discharges at a construction site changes from one individual to another, the permit shall be 'rat ferred t^ arcordanre with part 1 A 7 of the permit The Notice f Transfer form will be mailed to the permittee along with the permit certification. Additional copies are available from the Division. If the new responsible party will not complete the transfer form, the permit may be inactivated if the permittee has no legal responsibility, through ownership or contract, for the construction activities at the site. In this case, the new operator would be required to obtain permit coverage separately. .1. Duration of Permit The general permit will expire on June 30, 2007. The permittee's authority to discharge under this permit is approved until the expiration date of the general permit. Any permittee desiring continued coverage under the general permit must apply for recertification under the general permit at least 90 days prior to its expiration date. Nathan Moore March 11, 2002 VII CHANGES MADE AFTER PUBLIC NOTICE Several comments were received from'the Environmental Protection Agency (EPA). Changes based on these comments and additional internal review are discussed below: A. The EPA commented that language needs to be added to the permit addressing the certification requirements for inspection reports. Part I.E.1 of the Permit requires that all reports submitted to the Division include specific certification language. Because site inspections required by Part I. C.5 of the permit are not submitted to the Division, they are not covered under Part 1. C.5 of the Permit or Regulation 5 CCR 1002-61, Section 61.4(1)0, which require specific certification language. However, Regulation 5 CCR 1002-61, Section 61.8(4)(o)(ii)(B) does require that the permittee maintain a record summarizing the inspections that includes a certification that the site in compliance with the plan and the permit. Therefore, language has been added to Part I. C.5 of the Permit, requiring that a signed statement be included with all records of inspection on the status of compliance at the site. B. The EPA recommended that the Permit and Rationale be changed to indicate that the application is due ten days prior to the commencement of construction activities, instead of prior to the anticipated date of discharge. The Division agrees that this wording is preferable and more accurately indicates the Division's existing interpretation of the regulations. These changes have been made. C. The EPA expressed concern with requiring a permittee to transfer permit coverage in cases where the new responsible party may not be cooperative. Language has been added to the Permit and Rationale clarifying that termination of permit coverage is allowed when the permittee no longer has any legal responsibility through ownership or contract for the construction activity. D. The EPA commented on the lack of a definition for the terms "receiving water" and "ultimate receiving water A definition has been added to the Permit, and the term "ultimate receiving water" clarified to indicate that it means the first named receiving water, if the discharge initially goes to an unnamed ditch or storm sewer. Nathan Moore May 15, 2002 .. • . . • 2.. • • "4„ ,. • . . • " • • . . • .„ • . • .•„! vik".6S..• • „.• • • • - .'" , • . • k ' , (-) ' ' . •-,,,,, ,.. - ----r, • -A' '-- , , . ,_ . --' , --- -;:".7-t--- - • v?. 1., ' 1 .41 ..- -_-„, I 6'6' ‘ 4.4"46 -, ' - •`,.-: "4 ‘•-• ::6'.<--..-'<, ' ' \ --S-7'.6)'), ----,:c..-1„.--,.---,- :: 1 ) ---„-- 4--- -4 '1-1:-1)..'.W.: . _ 4:‘-;\k.:7' - -7N...• i , ' - L. - 1". • • '' • .--__:„. f -_,..,:;,,,z-", • - ; -..-1- , ' •••!C -.;,' 74,.,-.1...' - t.'-" - . .- . --s .:-.4,---1/2-, •-•.: . . _ . .,.. ? 5\ -- . r•-$13- it . - ,k • i A . ' --•"" k,' , . ,-"Cf-- . —"Z• _ 2 , . , . . , , .., , . i,,,,,,.., ,,,,,.. = . ci . . , ;,,,•;-,,,,,,,,' r ':'.-.... 1. zr, t...1 ,-,---:,-Tilis - . . \, ., k '4-• 1.1 E ' ck , T a ..i' , • 2 ---",„ _ ,,HP , -"-1Q-24- „ •-• — , .r, a) , , -,1'14r-s . ___79,4')- • ' co 0 0 •.-,,, 4 / , , .6'1, . • 0 \-. ' '• , 0 E ,_ . , .4Z3 a) ' E -, - 13 Iri 3> :E ' , z E co co \ i -. L- ‘.., , ‘. ,.... t.-,. -• — a. It -E ct , .< f.,----1 :-.--,t,.. j_ ,, ks .., ,,. /‘ - cj c,..--,,,, ..„,..›)A7 \ 8 i 1 1 r I ' 5 / j .,k.k• 4 -. / (7 " 2 co No , i ---T [ -.K f- (if- -- IL op , ‘ r `i ) \ '' N )7•,.\[-?? k6-7 i.li 9 , 40'. , •; _ , si 4ijIex-% , ,,\ , ,{, (C,,---;11,-.. <•.,L ,.i., *if — i i -,_ ,, - ) , ,----, \ f -v,,--' ,,, ,. r 1 ,,,s, A-, , 'Iti,V -. , , ') ) ,,,, 7 ),:b 6 A -- ' - - ' '- r 1 r. 4 / iN / I C./ \IC ---ii‘ c5 - k'{ .r-/. ) _ - km /Ix/ i orr 1, ,- - \ r / I Air 14\ ,, 1 : - .. -, , z z USDA Soil Types 1 -Aga very fine sandy loam, 0-3% slopes 36-Fluvaquents, 0-3% slopes 54-Panitchen loam, 1-6% slopes 56-Parachute-Irigul-Rhone association, 25-50% sl } \ 173{a. sE P. o. 0 \ \. L ; { j 0 \ cn tom ea ) \ \ Cowboy Chapel n ESHIA Report * 2 v 9 67 -Tosca channery loam, 25-80% slopes ƒ\\\\\/\\\//\\\\\\\\$\\\\\\\ Cowboy Chapel §) )]000 } d%!ƒ ©°o° LLL(5 — }j2 2)j) 2) £ J j} \ cn n co \ Lu : \ ) 2 )z ƒ ± u Surface Soil Slope \$ Reference: *Modified \/ ct Er) §/ o G \\ Forest Dominated Riparian obi Greasewood Fans and Flats Roan Cliffs Blazingstar \ 0 41-3 1-1 0-1 ) O. \ / \ Cl 0 ) 00 0 \ *9 • o , • o Mesic Upland Shrub § i Mountain Sagebrush $ Lakes and Rivers Aspen Forest $\ URS Washington Division PICEANCE BASIN NATURAL GAS DEVELOPMENT PROGRAM Chevron GARFIELD COUNTY, COLORADO SPECIFICATION FOR RE -VEGETATION OF DISTURBED AREAS 0 Approved for Construction B Updated with Specific State / County Requirements SMC 12-18-07 A Issued Preliminary for Review and Comments KCH JRV 8-17-07 REV. DESCRIPTION BY CHKD APVD RVWD DATE REVISIONS CLIENT: Chevron North America Exploration and Production PROJECT: Piceance Basin Natural Gas Development Program JOB NO.: 29454 DOC. NO.: PBSR-ALL-CIV-SPC-URS-00000-00004-00 H:\_Projects\Chevron\29021_CNAEP\SPECIFICATIONS\Civil\12-0-004 Revegetation rev 2 SMC.doc Washington Division Chevron ROO Date: 4/29/08 RE -VEGETATION OF DISTURBED AREASDoc. PICEANCE NATURAL GAS DEVELOPMENT PROGRAM No. PBSR-ALLCIV-SPC-URS- 00000-00004-00 Rev: 0 Page: 2 of 10 TABLE OF CONTENTS SECTION PAGE 1. GENERAL 3 1.1 Scope 3 1.2 Related Specifications 3 1.3 Definitions 3 1.4 References and Standards 3 1.5 Submittals 4 1.6 Quality Assurance 4 1.7 Delivery, Storage, and Handling 4 1.8 Warranty 4 2. PRODUCTS 5 2.1 Materials 5 3. EXECUTION 6 3.1 General 6 3.2 Seeding Methods for Slopes Less than 3% 6 3.3 Seeding Methods for Slopes Greater than 3% 7 3.4 Mulching 7 3.5 Maintenance 7 3.6 Workmanship 8 3.7 Field Quality Control 8 3.8 Adjusting and Cleaning 8 3.9 Protection 8 Chevron Washington Division Date: 4/29/08 RE -VEGETATION OF DISTURBED AREAS PICEANCE NATURAL GAS DEVELOPMENT PROGRAM Doc. No. PBSR-ALLCIV-SPC-URS- 00000-00004-00 Rev: 0 Page: 3 of 10 1. GENERAL 1.1 Scope This Specification covers the site conditions, materials and construction requirements for native grass seeding for the Chevron Piceance Basin Natural Gas Development Program. Services for this work shall consist of, but not necessarily be limited to the following: general preparation, preparation for seeding, seed placement, mulching, maintenance, workmanship, field quality control, adjusting, cleaning and protection. State and local laws concerning pollution abatement will be followed. 1.2 Related Specifications 1.2.1 Specification No.12-0-002 — Site Preparation and Earthwork 1.2.2 Specification No.12-0-003 — Erosion and Sediment Control 1.3 Definitions 1.3.1 Owner: Chevron North America Exploration and Production Company 1.3.2 Engineer: URS Corporation Washington Division. All references to Engineer refer to the Engineer or his/her designated representative. 1.3.3 Contractor: TBN 1.3.4 Subcontractor: Firm undertaking the scope of work as defined in this Specification 1.3.5 State: Refers to the state of Colorado 1.4 References, Standards, and Guidance The codes, standards, regulations, and guidance documents of the following organizations in effect as of August 10, 2007 form a part of this Specification to the extent indicated by the references thereto: 1.4.1 Occupational Safety and Health Act (OSHA), 24, CFR 1926, OSHA Standards for the Construction Industry. 1.4.2 Colorado Department of Transportation (CDOT), Standard Specifications for Road and Bridge Construction. 1.4.3 Bureau of Land Management (BLM) — Oil and Gas, Surface Operating Standards for 00 and Gas Exploration and Development. Fourth Edition. 1.4.4 Garfield County Vegetation Management Guidance — Noxious Weed List, Reclamation Standards, Weed Management Plan, Re -vegetation Guidelines Should a conflict be found to exist between any applicable portion of the referenced codes and standards and this Specification, the conflict shall be submitted to the Engineer for resolution before proceeding with the affected work. Washington Division Chevron 1110 Date: 4/29/08 RE -VEGETATION OF DISTURBED AREASDoc. PICEANCE NATURAL GAS DEVELOPMENT PROGRAM No. PBSR-ALLCIV-SPC-URS- 00000-00004-00 Rev: 0 Page: 4 of 10 1.5 Submittals 1.5.1 If requested by the Engineer, furnish an affidavit from each manufacturer or producer certifying that the materials or products delivered to the Project site meet the specified requirements. A. However, such certification shall not relieve the Subcontractor from the responsibility of complying with added requirements specified herein. 1.5.2 Furnish to Engineer, a signed statement certifying that the seed furnished is from a lot that has been tested by a recognized laboratory for seed testing, six months prior to date of delivery. A. Provide certification tags for the seeds. 1.6 Quality Assurance Qualifications: Work to be performed shall be executed by a single firm who specializes and has full knowledge and experience in re -vegetating disturbed areas in Colorado using native species and who has satisfactorily performed work of this type on other projects of comparable size and scope as this Project. 1.7 Delivery, Storage, and Handling 1.7.1 Seed: Deliver each specified seed species to Project site in separate, sealed, original containers which show an analysis of the seed made by an approved authority. A. Seed shall be fresh stock and labeled in accordance with U.S. Department of Agriculture Rules and Regulations under the Federal Seed Act. B. Upon request of the Engineer or its designated representative, submit two copies of invoices showing type and quantity of seed materials. 1.7.2 Mulch (if used): Do not use old dry straw that breaks in the crimping process in lieu of bending. A. Such straw will not be accepted, and shall be removed from the Project site. B. All mulch shall be certified noxious weed free. 1.8 Warranty 1.8.1 Photographic documentation of the construction site is required to establish the baseline for the warranty. 1.8.2 Subcontractor shall continue to monitor the re -vegetated area and reseed areas as required until the conditions in B. are met. A. Warranty period shall commence upon acceptance of work by the Engineer. B. Warranty period shall end when the Engineer has determined that the vegetation density of the reseeded area has reached 70 percent of the original vegetation density. 1.8.3 Reseed all areas where there is not a satisfactory stand of native grass as determined by the Engineer. The length of the warranty period will vary by season and will be agreed to between Subcontractor and Engineer at the time of re -vegetation activities. Washington Division Chevron ONO ONO Date: 4/29/08 RE -VEGETATION OF DISTURBED AREAS PICEANCE NATURAL GAS DEVELOPMENT PROGRAM Doc. No. PBSR-ALLCIV-SPC-URS-1 00000-00004-00 5 of 10 Rev: 0 Page: A Process will be repeated until the stand of native grass over all areas designated for re - vegetation has met the 70 percent of original vegetation criterion. Reseeding shall be at the Subcontractor's expense. 2. PRODUCTS 2.1 Materials 2.1.1 Seed: Seed shall be in accordance with the seed mix identified in B. Seed and seed labels shall comply with all current state and federal regulations and shall be subject to the testing provisions of the association of official seed analysis. A. Provide fresh, clean, new -crop seed complying with the tolerance for purity and germination established by the Official Seed Analysts of North America. B. Provide seed of the grass species, proportions, and minimum percentages of purity, germination, and maximum percentage of weed seed specified as follows. Seed Mix for Sites below 7000 ft Scientific Name Seeds per pound Common Name/ Preferred Cultivar PLS/ ft= % of mix by PLS weight Application Rate (lbs PLS/acre) Achnathemum hymenoides 140,000 Indian ricegrass/ Paloma* 4 12.5 1.25 Hesperostipa comata comata 115,000 Needle and thread 4 15 1.5 Pascopyrum smithii 140,000 Western wheatgrass/ Arriba* 10 31 3.1 Pseudoroegneria spicata spicata 140,000 Bluebunch wheatgrass/ P7 10 31 3.1 Sitanion hystrix 192,000 Bottlebrush/squirreltail 4 10 0.90 Poa canbyi 925,000 Canby bluegrass/ Canbar 4 0.5 0.19 Total 36 100 10.04 Use only this cultivar, as recommended by Natural Resources Conservation Service and the Colorado Natural Heritage Program, 1998. Seed Mix for Sites above 7000 ft See Attachment 1, which describes seed mixes for three higher -elevation environments developed by the Bureau of Land Management Glenwood Springs Energy Office (memo dated April 16, 2007). C. Notify the Engineer in writing prior to seeding, for review of the following: • Seed mix to be used. • Percentage of purity and germination. • Pounds of pure live seed per pound of seed. • Selected method of seeding. Washington Division Chevron IVO Date: 4/29/08 RE -VEGETATION OF DISTURBED AREAS PICEANCE NATURAL GAS DEVELOPMENT PROGRAM Doc. No. PBSR--SPC-URS- 00000-00004-00004-00 Rev: 0 Page: 6 of 10 D Furnish seed free from noxious weeds. E. Do not use seed that has become wet, moldy or otherwise damaged in transit or in storage. F. Use only seeds from a lot tested by a recognized laboratory within six months prior to delivery. G. Seed purity, germination, and mixture proportions shall meet the requirements listed in B above. 2.1.2 Topsoil: Use nearby topsoil stockpiles that were set aside as part of the excavation. Areas with minimal topsoil may require the addition of mulch. A. See 3.2 and 3.3 for soil preparation requirements. 3. EXECUTION 3.1 General 3.1.1 Do not start preparation work until after all related site work within the areas to be revegetated, including site utilities, has been completed, tested, and backfilled to the satisfaction of the Contractor. The following general requirements apply: A. Seeding activities should be limited to cooler, wetter months (typically September through June) when conditions are favorable for germination, B. Fertilization is not required (promotes rapid weed growth), C. Do not seed when wind velocity exceeds five miles per hour, and D. Sow no less than the quantity of seed specified. 3.2 Seeding Methods for Slopes Less than 3% 3.2.1 Each species of seed shall be in separate bags so that each size group of seed can be metered at the appropriate rate. 3.2.2 Small seeds, such as canby bluegrass (Poa canbyl), can be difficult to apply at the small rates required. Use of wheat bran or rice hulls or other adjuvant to assist metering of the small seeds may be required. 3.2.3 Preferred Method: Multiple Seed Bin Rangeland Drill A. No soil preparation required other than simple grading to slope and waterbars at 50 -foot spacing. 3.2.4 Alternative Methods A. Broadcast seeding methods: Seeding rate must be doubled for broadcast application. 1. Harrow: Harrow with just enough soil moisture to create a rough surface; broadcast seed and re -harrow at 90° to first harrow. Washington Division Chevron 141101 4 Date: 4/29/08 RE -VEGETATION OF DISTURBED AREAS Doc. No. PBSR-ALLCIV-SPC-URS- 00000-00004-00 Rev: 0 PICEANCE NATURAL GAS DEVELOPMENT PROGRAM Page: 7 of 10 2. Hand raking and broadcast seeding followed by e -raking at a 90° angle to the first raking. B. Hydro -seeding C. Other methods as agreed to by Engineer. 3.2.5 Application Rates: A. See application rates in 2.1.18. 3.3 Seeding Methods for Slopes Greater than 3% 3.3.1 Imprinting seedbed is required. A. Imprinting can be accomplished using dozer tracks or furrows perpendicular to the direction of the slope. B. When hydro -seeding, imprinting shall be conducted prior to seeding. C. Harrowing and broadcast seeding: imprinting shall be done as part of harrowing. D. Furrowing: obtain approval for method from Engineer. 3.3.2 If mulch will be crimped into the soil surface, imprinting is not required. 3.4 Mulching Mulching is not required for most methods. Temporary and permanent erosion control blankets may be used or straw can be crimped into soil during drill seeding. 3.5 Maintenance Maintain until the revegetated area has reached 70 percent of original vegetation density. 3.5.1 Begin maintenance of seeded areas immediately after each area is planted and continue until the Owner's acceptance of the Project. 3.5.2 Maintain seeded by preventing erosion and replanting as required to meet the 70 percent of original vegetation criterion. 3.5.3 Replant bare areas using the same materials specified above. 3.5.4 When maintenance is taken over by the Owner during the guarantee period, the Subcontractor shall periodically inspect the maintenance operation of the Owner. A. The Subcontractor shall promptly report to the Owner any methods, practices or operations which he considers unsatisfactory, not in accord with his interest or not in accord with good horticultural practices. B. Failure of Subcontractor to inspect and report shall be construed as an acceptance of Engineer operations. Washington Division Chevron 11110 Date: 4/29/08 RE -VEGETATION OF DISTURBED AREASDoc. PICEANCE NATURAL GAS DEVELOPMENT PROGRAM No. PBSR--BPC-URS- 00000-00004-00004-00 Rev: 0 Page: 8 of 10 1. No claims from the Subcontractor will be recognized thereafter should any defects develop later that are the result of such methods, practices or operations. 3.6 Workmanship 3.6.1 Perform all Work in a careful and orderly manner with due consideration for the protection of adjoining property. 3.6.2 Keep drainage structures clean during installation of Work. 3.7 Field Quality Control 3.7.1 Acceptance for Start of Maintenance: Notify the Contractor or its designated representative of completion of all seeding required. A. Review of seeded areas will be by the Contractor or its designated representative, and he will determine whether Work is acceptable and whether the maintenance period can begin. 3.7.2 Final Acceptance: Notify Contractor in writing of completion of the required maintenance. A. Within ten days of owner's notification, inspection for final acceptance will be made by a representative for the Contractor and the Subcontractor. B. For final acceptance the terms of the warranty must be met and the Project site shall be in acceptable clean condition. 3.8 Adjusting and Cleaning 3.8.1 Work is complete when the premises are clear of all rubbish, refuse and debris, leaving premises in a clean and orderly condition. 3.8.2 Repair damage done to property on or off premises by reason of required Work without additional cost to the Contractor. 3.9 Protection Restrict foot and vehicular traffic on seeded areas until the completion of the established period. Washington Division Chevron tella 1000 Date: 4/29/08 RE -VEGETATION OF DISTURBED AREASDoc. No. PBSR--SPC-URS- PLS Ibstacrex Plant the Fallowing (1085 Total) Indian Ricegrass .4cisnarhermn [Orysopsts] knnenotdes 00000-00004-00004-00 Rev: 0 PICEANCE NATURAL GAS DEVELOPMENT PROGRAM Page: 9 of 10 Attachment 1: Seed Mixes for Environments above 7000 ft Source: Bureau of Land Management, Glenwood Springs Energy Office, Memo, April 16. 2000 Table 1-2. Pinyon -Juniper Woodland andtor MountainfWyotning Big Sagebrush Shrubland Common Name Scientific Names Variety Season Form PLS Ibstacrex Plant the Fallowing (1085 Total) Indian Ricegrass .4cisnarhermn [Orysopsts] knnenotdes Nezpar, Paloma, Rsnuocl: Cool Bunch 1.9 and Both of the Following (1546 Each, 30% Total) Galleta Pleuraphts [Hilarfal fmuesi! Viva florets 'Vann Bunch 2.5 Bluebunch Vheatgrass Pscsedor•oegrerta spieara, Agrop von spicnnon SAecavataaer, P-7, Coot Bunch 2.8 and One of the Following (2080 Total) Thichspike Wheatgrass E!i mus lanceotahs ssa. Itnrceolams, Agr•omran daststnrhruus Critaua. Schwendimar Cool Sod -forming 3.4 Slender Wheatgrass Eernms n•aetnraulus, Agropsa•on nnehrrashase San Luis Cool Bunch 3.3 and Two of the Following (404 Total) Mutrongrass Porfendtertana Cool Bunch 0.6 Sandberg Bluegrass Poet sandbergii, Pon secunda Cool Bunch 0.6 Bottlebmsh Squitreltail Eli;: s elymoides, S'iranion insnit- Cool Bunch 22.7 1FBased on 60 pure live seeds /PLS) per• square foot, drill -seeded. Double this rate t120PLS per square foot/ if broadcast a• hpdroseeded. Washington Division Chevron ONO 1100 Date: 4/29/08 RE -VEGETATION OF DISTURBED AREASDoc. No. PBSR--SPC-URS- PLS lbs acre* Plant Both of the Following (20% Each, 40% Total) Tlrickspike iVheatgrass Elrmus Ianceolanrs ssp. lnnceolams, Agr•oprron dasrstncf_rmn 00000-00004-00004-00 Rev: 0 PICEANCE NATURAL GAS DEVELOPMENT PROGRAM Page: 10 of 10 Table 14. Mixed Mountain Shrubland, Including Oakbrush Cominon Name Scientific Names Variety Season Form PLS lbs acre* Plant Both of the Following (20% Each, 40% Total) Tlrickspike iVheatgrass Elrmus Ianceolanrs ssp. lnnceolams, Agr•oprron dasrstncf_rmn Critana, Schwendimar Cool Sod -forming 3.4 Bluebunch R•Leatgmss Pseudor•oegnerin sp(cata, Agroprron spicamm SP-7, uato Anatone Cool Bunch 3.7 and One of the Following (20% Total) Bottlebrush Squisreltail El3mus elrmoides, Siranion Jq'sni.x Cool Bunch 2.7 Slender Wbeatgrass Elrmus o•acl:•pcauh:s,.lgropvron nnchirnuhor: San Lnis Cool Bunch 3.3 and One of the Following (20% Total) Canby Bluegrass Poa canbyi, P. secunda Canbar Cool Bunch 0.6 Mutton Bluegrass Poo f ndleriana Cool Cool Bunch 0.6 and One of the Following (10% Total) Letterman Needlegrass Achnather•sm: [Stipa] lerersnarii Sed -forming Cool Bunch 1.7 Columbia Needlegrass Aclnsatmwn (Snpn] nelsosii, Stipa colun:biana Cool Bunch 1.7 and One of the Following (10% Total) Indian Ricegrass Achnather um (Or3sopsis] Itymenoides Nezpar, Paloma, Rimrock Cool Bunch 1.9 Isnegrass Eoelerin man•antha, K cristara Cool Bunch 0.1 'Based on 60 pure lire seeds (PLS) per square foot, drill -seeded. Double this rote (120 PLS per square foot) if broadcast or hrdroseeded. Table 1-4. Spruce -Fir Forest, Including Mountain Meadows Common Name Scientific Names Variety Season Form PLS lbs/acre` Plant Both of the Following (20% Each, 40% Total) Mountain Brome Bron:opsis proms] magrnnrus Garnet Cool Bunch 51 Slender LBheatgrass Elpmus nachyeauhc, Agropn•oi nndnrauiunr San Lnis Cool Bunch 3.3 and Three of the Following (20% Each, 60% Total) Lenerman Needlegrass Achud:holm [Sopa] letternnnnii Cool Bunch 3,5 Blue Wildnye Elrmus glnucns Arlington Cool Bunch 4.5 Thi<L-spJ:e R'heaterass Elwin, lanceolams ssp- lmsceolams, Agr•oprron dasmtarhIsn: Critana, Schwendimar Cool Sod -forming 3.4 Idaho Fescue Fesmca idahoensis Joseph Cool Bunch 1 2 Wheeler Bluegrass Poa rren•osa Cool Sed -forming 0.6 *Based or 60 pure live seeds (PLS)per square foot, drill -seeded Double This rate (120 PLS per square foot) if broadcast or Jiydroseeded. TYPICAL STORM -WATER BEST MANAGEMENT PRACTICE (BMP) DETAILS Table of Contents 1.0 Filter Berms 1 2.0 Land Grading 2 3.0 Level Spreader 4 4.0 Erosion/Sediment Control Logs/Wattles 6 5.0 Riprap 9 6.0 Sediment Traps 12 7.0 Silt Fence 14 8.0 Straw Bale Barriers 16 9.0 Surface Roughening 18 10.0 Terracing 21 11.0 Vegetative and Grass Buffers 23 12.0 Waterbars 25 13.0 Diversion Ditches/Berms 27 14.0 Gravel Surfacing 29 15.0 Sediment Control Berms 31 16.0 Check Dams 33 17.0 Drainage Dips 35 18.0 Erosion Control Blankets/Mats 38 19.0 Slope Drains 41 20.0 Slope Stabilization 43 21.0 Mulching 45 22.0 Culverts 48 23.0 Culvert Inlet and Outlet Protection 50 24.0 Revegetation 51 25.0 Turnouts 53 26.0 Stabilized Entrance/Exit 55 27.0 Retaining Walls 57 28.0 Concrete Washout Facilities 58 29.0 Sanitary/Septic (Port -O -Let) Waste Management 61 30.0 Inlet Protection 63 31.0 Temporary Sediment Basins 70 Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 1 Piceance Basin Natural Gas Development Program 1.0 FILTER BERMS Description: A gravel or stone filter berm is a temporary ridge made up of loose gravel, stone, or crushed rock that slows, filters, and diverts flow from an open traffic area and acts as an efficient form of sediment control. A specific type of filter berm is the continuous berm, a geosynthetic fabric that encapsulates sand, rock, or soil. When and Where to use it: • Gravel or stone filter berms are most suitable in areas where vehicular traffic needs to be rerouted because roads are under construction, or in traffic areas within a construction site. • The following construction guidelines should be considered when building the berm: o Well -graded gravel or crushed rock should be used to build the berm. o Berms should be spaced according to the steepness of the slope, with berms spaced closer together as the slope increases. o Sediment that builds up should be removed and disposed of and the filter material should be replaced. Regular inspection should indicate the frequency of sediment removal needed. Limitations and When and Where NOT to use it: • Berms are intended to be used only in gently sloping areas. • Berms are easily damaged by storm -water flow and if not maintained properly, do not last long. • Berms require maintenance due to clogging from mud and soil on vehicle tires. Construction Detail and Maintenance Requirements: • Berms should be inspected after every rainfall to ensure that sediment has not built up and that no damage has been done by vehicles. • It is important that repairs be performed at the first sign of deterioration to ensure that berms are functioning properly. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 1 Piceance Basin Natural Gas Development Program 2.0 LAND GRADING Description: Land grading involves reshaping the ground surface to planned grades as determined by an engineering survey, evaluation, and layout. Land grading provides more suitable topography for buildings, facilities, and other land uses and helps to control surface runoff, soil erosion, and sedimentation during and after construction. When and Where to use it: • Sites with uneven or steep topography or easily erodible soils, because it stabilizes slopes and decreases runoff velocity. • Grading activities should maintain existing drainage patterns as much as possible. • Before grading activities begin, decisions must be made regarding the steepness of cut - and -fill slopes and how the slopes will be protected from runoff, stabilized, and maintained. Limitations and When and Where NOT to use it: • Improper grading practices that disrupt natural storm water patterns may lead to: o Poor drainage. o High runoff velocities. o Increased peak flows during storm events. • Clearing and grading of the entire site without vegetated buffers may promote off-site transport of sediments and other pollutants. • The grading plan must be designed with erosion and sediment control and storm -water management goals in mind. • Grading crews must be carefully supervised to ensure that the plan is implemented as intended. Construction Detail and Maintenance Requirements: • All graded areas and supporting erosion and sediment control practices should be periodically checked, especially after heavy rainfalls. • All sediment should be removed from diversions or other storm -water conveyances promptly. • If washouts or breaks occur, they should be repaired immediately. • Prompt maintenance of small-scale eroded areas is essential to prevent these areas from becoming significant gullies. • A grading plan should be prepared that establishes and includes: o Identification of areas of the site to be graded. o How drainage patterns will be directed. o How runoff velocities will affect receiving waters. o Information regarding when earthwork will start and stop. o The degree and length of finished slopes. o Where and how excess material will be disposed of (or where borrow materials will be obtained if needed). o Berms, diversions, and other storm -water BMPs that require excavation and filling should be incorporated into the grading plan. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 2 Piceance Basin Natural Gas Development Program Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 3 Piceance Basin Natural Gas Development Program 3.0 LEVEL SPREADER Description: Level spreaders are devices used at storm -water outlets to spread out collected storm -water flows into sheetflow (runoff that flows over ground surface in a thin, even layer). Typically, a level spreader consists of a depression in the soil surface that spreads the flow onto a flat area across a gentle slope. Level spreaders then release the storm -water flow onto level areas stabilized by vegetation to reduce speed and increase infiltration. When and Where to use it: • Level spreaders are most often used as an outlet for temporary or permanent storm -water conveyances or dikes. • Runoff that contains high sediment loads should be treated in a sediment trapping device prior to release into a level spreader. Limitations and When and Where NOT to use it: • Can easily develop "short circuiting" (concentration of flows into small streams instead of sheetflow over the spreader) because of erosion or other disturbance. • Cannot handle large quantities of sediment -laden storm -water. Construction Detail and Maintenance Requirements: • The length of the spreader depends upon the amount of water that flows through the conveyance. • Larger volumes of water need more space to even out. • Level spreaders are generally used with vegetative and grass buffers (also see Vegetative and Grass Buffers BMP). • The depressions are seeded with vegetation (also see Revegitation BMP). • Level spreaders should be constructed on natural soils and not on fill material. • The entrance to the spreader should be level so that the flow can spread out evenly. • Level Spreader should have a grade of 0 percent; minimum width should be 6' and minimum depth should be 6". • The spreader should be inspected after every storm event to check for damage. • If ponding or erosion channels develop, the spreader should be regraded. • Dense vegetation should be maintained and damaged areas reseeded as needed. Doc. No.' PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 4 Piceance Basin Natural Gas Development Program Figure: Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 5 Piceance Basin Natural Gas Development Program 4.0 EROSION/SEDIMENT CONTROL LOGS/WATTLES Description: An erosion/sediment control log/wattle consists of a wattle with an excelsior, straw, compost, or coconut fill material constructed to create a pervious filter, able to facilitate overtopping. The log/wattle promotes sediment removal on the upgradient side and a reduction in flow velocities. When and Where to use it: • At the top, face and at grade breaks of exposed and erodible slopes. • As check dams for small runoff volume circumstances (i.e., in roadway ditches and channels downstream of disturbed soils). • Around storm drain inlets associated with disturbed areas. • Outfalls of small drainage channels or structures. Limitations and When and Where NOT to use it: • Not suitable for rock subgrades where stakes cannot be securely installed. • Offer a potential for accidental introduction of undesirable weed species if filled with straw. • Not to be used in place of linear sediment barrier such as silt fence. • Not practicable where large flows are involved. Construction Detail and Maintenance Requirements: • Erosion/sediment control logs/wattles should be trenched into the ground a minimum of 2 inches and staked or stapled into the ground. • Sediment accumulated upstream of wattles should be removed when the sediment depth upgradient of the log/wattle is within''/ of the height of the crest or when debris accumulation compromises the effectiveness of the feature. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 6 Piceance Basin Natural Gas Development Program Photographs and Figure: Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Chevron North American Exploration and Production Company 7 Skinner Ridge Stomt-Water Management Plan Piceance Basin Natural Gas Development Program Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm-Water Management Plan Chevron North American Exploration and Production Company 8 Piceance Basin Natural Gas Development Program 5.0 RIPRAP Description: Riprap consists of large stone units that may be grouted in place or planted with vegetation between units. When and Where to use it: • Rock riprap placed in cut -to -fill slope transitions. • To provide erosion protection at structures, where rock riprap is placed along the soil interface of concrete and metal structures. • To provide inlet and outlet scour and erosion protection, where rock riprap or grouted riprap is placed at inlet and outlet ends of culverts, conduits, or channels. • Where discharge velocities and energies at the outlets of culverts, pipes or channels are sufficient to erode the downstream channel. • At discharge outlets that carry continuous flows of water. • At points where lined conveyances discharge to unlined conveyances. Limitations and When and Where NOT to use it: • Rock riprap transitions reduce erosion only when they have been sized and built properly. • Loose rock may be washed away during high flows. • Freeze/thaw cycles may break up grouted riprap. Construction Detail and Maintenance Requirements: • A sediment trap below the outlet is recommended if runoff is sediment -laden. • Inspect for signs of slope erosion under and around the rock protection. • Inspect for signs of erosion and undercutting around structures. • Check for erosion and displacement of rock at inlets and outlets. • Inspect for displacement of riprap or damage to underlying fabric, and signs of scour beneath the riprap or around the outlet. • Replace rock and repair as needed. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 9 Piceance Basin Natural Gas Development Program Figures: Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 10 Piceance Basin Natural Gas Development Program .ems `411.4". r �✓ Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 11 Piceance Basin Natural Gas Development Program 6.0 SEDIMENT TRAPS Description: A sediment trap consists of an earthen berm with a small upstream basin that acts to trap runoff and facilitate the settling of suspended particles, similar to the sediment basin. The discharge or outlet point is established with a riprap weir. When and Where to use it: • Sediment traps can be used for upstream disturbed areas less than 1 acre. • Where there is sufficient space and appropriate topography. • Be located in an area that is easily accessible to maintenance crews for removal of accumulated sediment. • Positioned so that it captures sediment from the entire upstream disturbed area. • Where a permanent detention basin is planned for the site. Limitations and When and Where NOT to use it: • Disturbed areas greater than 1 acre require a sediment basin. • Sediment traps are not to be installed in active streams. Construction Detail and Maintenance Requirements: • The sediment trap should be constructed with clean fill, free of roots, woody vegetation, stones, or other objectionable material. • Locate sediment traps as near as practical to areas producing the sediment. • The outlet can be earthen, pipe, gravel or via an existing storm drain. o An earthen outlet is formed by excavation and/or embankment and is seeded with temporary or permanent vegetation. o Pipe outlets consist of perforated riser with outlet pipe of corrugated metal. o Pipe outlets should be constructed in such a way that the top of the o embankment is one and a half feet above the crest of the riser. The top 2/3 of the riser should be perforated with 1/2 -inch diameter holes. o Gravel outlets should consist of a crushed stone section located at the low point of the embankment. Their length should be at least six times the number of acres in the drainage area. The crest of a gravel outlet should be one foot below the top of the embankment. • A filter fabric can be installed inside the gravel filter to improve sediment trapping efficiency, but may increase the probability of clogging the outlet. • Traps should be inspected after each storm event to ensure proper drainage from the collection pool to determine the need for structural repairs. • Erosion from the earthen embankment or stones moved from rock dams should be replaced immediately. • Sediment should be removed from the basin when its storage capacity has reached approximately 50 percent. • Trash and debris from around dewatering devices should be removed promptly after rainfall events. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 12 Piceance Basin Natural Gas Development Program Photograph and Figure: Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 13 Piceance Basin Natural Gas Development Program 7.0 SILT FENCE Description: A silt fence is a temporary sediment barrier constructed of filter fabric stretched across supporting posts. The bottom edge of the fabric is entrenched and covered with backfill. When and Where to use it: • On the down gradient perimeters of a construction site. • On a contour to control overland sheet flow. • At the top or toe of a steep slope. • As a form of inlet and/or outlet protection (also see Culvert Inlet and Outlet Protection BMP). Limitations and When and Where NOT to use it: • In areas of concentrated flows such as in ditches, swales or channels that drain areas greater than 1.0 acre. • At the top of a slope or at high points which do not receive any drainage flows. Construction Detail and Maintenance Requirements: • Place silt fence along contours. • Stakes or posts should be to the downhill side of the fence. • The bottom of the fabric must be continuously and securely anchored for its entire length to prevent undermining. • Increase the elevation at the ends of the silt fence installation to prevent "end runs." • Inspect silt fences regularly and frequently, as well as after each rainfall event, to make sure that they are intact and that there are no gaps where the fence meets the ground or tears along the length of the fence. • If gaps or tears are found, repair or replace the fabric immediately. • Remove accumulated sediments from the fence base when the sediment reaches one-third to one-half the fence height. • Remove sediment more frequently if accumulated sediment is creating noticeable strain on the fabric and the fence might fail from a sudden storm event. • When silt fences are removed the accumulated sediment must be removed as well. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 14 Piceance Basin Natural Gas Development Program Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Chevron North American Exploration and Production Company 15 Skinner Ridge Storm -Water Management Plan Piceance Basin Natural Gas Development Program 8.0 STRAW BALE BARRIERS Description: A straw bale barrier is a temporary sediment barrier consisting of a row of entrenched and anchored straw bales used to retain sediment from runoff in small drainage areas of disturbed soil. When and Where to use it: • At the base of a slope. • On the down gradient perimeters of a construction site. • On a contour to control overland sheet flow. • As a form of check dam (also see Check Dam BMP). • As a form of inlet and/or outlet protection (also see Culvert Inlet and Outlet Protection BMP). Limitations and When and Where NOT to use it: • In areas of concentrated flows such as in ditches, swales, or channels that drain areas greater than 1.0 acre (unless used as a form of check dam). • At the top of a slope or at high points which do not receive any drainage flows. • On slopes greater than 10:1 (H: V). Construction Detail and Maintenance Requirements: • Locate straw bale barriers on a level contour. • Straw bales should be placed at a maximum interval of 50 feet (a closer spacing is more effective), with the first row near the toe of slope. • Turn the ends of the straw bale barrier up slope to prevent runoff from going around the barrier. • Allow sufficient space up slope from the barrier to allow ponding, and to provide room for sediment storage. • For installation near the toe of the slope, consider moving the barrier away from the slope toe to facilitate cleaning. • To prevent flow behind the barrier, sand bags can be placed perpendicular to the barrier to serve as cross barriers. • Maximum flow path to the barrier should be limited to 100 feet. • Straw bale barriers should consist of two parallel rows with: o The ends of bales butted tightly. o Butt joints staggered between front and back rows. o Each row of bales trenched in and firmly staked. • Straw bale barriers are limited in height to one bale laid on its side. • Anchor bales with either two wood stakes or four bars driven through the bale and into the soil. Drive the first stake towards the butt joint with the adjacent bale to force the bales together. • Inspect BMPs prior to forecasted rain, daily during extended rain events, after rain events, weekly during the rainy season, and at two-week intervals during the non -rainy season. • Straw bales degrade, especially when exposed to moisture. Rotting bales will need to be replaced on a regular basis. • Replace or repair damaged bales as needed. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-0Q Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 16 Piceance Basin Natural Gas Development Program • Repair washouts or other damages as needed. • Sediment that accumulates in the BMP must be periodically removed in order to maintain BMP effectiveness. • Sediment should be removed when the sediment accumulation reaches one-third of the barrier height. • Remove straw bales when no longer needed. Remove sediment accumulation, and clean, regrade, and stabilize the area. Photograph: Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 17 Piceance Basin Natural Gas Development Program 9.0 SURFACE ROUGHENING Description: Surface roughening is a temporary erosion control practice whereby the soil surface is roughened by the creation of grooves, depressions, or steps that run parallel to the contour of the land. When and Where to use it: • Surface roughening is appropriate for all slopes and should be performed immediately after rough grades have been established in an area. • Surface roughening can also be used to help establish vegetative cover by reducing runoff velocity and giving seed an opportunity to take hold and grow. • Surface roughening can be used in combination with other erosion control measures such as mulching and seeding. Limitations and When and Where NOT to use it: • Slopes that are not smooth -graded and are left sufficiently rough after final grading do not need further roughening to control erosion. • Surface roughening alone is not sufficient to stabilize a slope for long periods of times, further stabilization measures should be implemented within two weeks of grading. • Extremely sandy or rocky soils are not well suited for surface roughening.. Construction Detail and Maintenance Requirements: • Cut Slope Roughening: o Stair -step grade or groove the cut slopes that are steeper than 3:1. o Use stair -step grading on any erodible material soft enough to be ripped with a bulldozer. Slopes consisting of soft rock with some subsoil are particularly suited to stair -step grading. o Make the vertical cut distance less than the horizontal distance, and slightly slope the horizontal position of the "step" in toward the vertical wall. o Groove the slope using machinery to create a series of ridges and depressions that run across the slope, on the contour. • Fill Slope Roughening: o Place fill slopes with a gradient steeper than 3:1 in lifts not to exceed 8 inches, and make sure each lift is properly compacted. o Ensure that the face of the slope consists of loose, uncompacted fill 4 -6 inches deep. o Use grooving or tracking to roughen the face of the slopes, if necessary. o Apply seed, fertilizer and straw mulch then track or punch in the mulch with the bulldozer. o Do not blade or scrape the final slope face. • Roughening With Tracked Machinery: o Limit roughening with tracked machinery to soils with a sandy textural component to avoid undue compaction of the soil surface. o Operate tracked machinery up and down the slope to leave horizontal depressions in the soil. Do not back -blade during the final grading operation. o Immediately seed and mulch roughened areas to obtain optimum seed germination and growth. • During construction, inspect BMPs daily during the workweek. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 18 Piceance Basin Natural Gas Development Program • Schedule additional inspections during storm events. • Check for erosion and sloughing, and make any required repairs. Photograph and Figure: Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 19 Piceance Basin Natural Gas Development Program —Staked Slope Line 5% Width Varies With Slope Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 20 Piceance Basin Natural Gas Development Program 10.0 TERRACING Description: Sediment can be controlled and runoff interrupted to reduce erosion on slopes that are particularly steep by the use of terracing. During grading, relatively flat sections, or terraces, are created and separated at intervals by slope segments. The slope segments are prone to erosion, however, and must be maintained. When and Where to use it: • Gradient terraces are most suitable for use in areas with existing or expected water erosion problems and limited or no vegetation, and they are only effective when there are suitable runoff outlets provided. • They are usually limited to use on long, steep slopes with water erosion problems, or where it is anticipated that water erosion will be a problem. Limitations and When and Where NOT to use it: • Terraces should not be constructed on slopes containing rocky or sandy soil. • Terraces are not appropriate for use on steep or shallow soils. • If too much water permeates the soil in a terrace system, sloughing could occur, and cut and fill costs could increase substantially. Construction Detail and Maintenance Requirements: • Gradient terraces should be designed with adequate and appropriate outlets and should be installed according to a well-developed plan after conduction of an engineering survey and layout. • Acceptable outlets include grassed waterways, vegetated areas, or tile outlets. • Any outlet that is used should be able to redirect surface runoff away from the terraces and toward an area that is not susceptible to erosion or other damage. • General specifications require that: o Whenever possible, vegetative cover should be used in the outlet. o At the junction of the terrace and the outlet, the terrace's water surface design elevation should be no lower than the outlet's water surface design elevation when both are performing at design flow. o During construction of the terrace system, dust control procedures should be followed. o Proper vegetation/stabilization practices should be followed while constructing terraces. • Regular inspections of the terraces should occur after any major storms and at least once a year to ensure that the terraces are structurally sound and have not been subject to erosion. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 21 Piceance Basin Natural Gas Development Program Photograph: Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 22 Piceance Basin Natural Gas Development Program 11.0 VEGETATIVE AND GRASS BUFFERS Description: Vegetative and grass buffers are used to maintain vegetated areas that are down gradient of earthwork activities. Creating or leaving existing green belts intact can slow sheet flows, act as a natural sediment barrier and protect the site perimeter. When and Where to use it: • At the bottom of sloped impervious areas. • Where overland sheet flow rather than concentrated or channelized flow will occur. • Where larger sediment from runoff off is anticipated from impervious areas. • Vegetative and grass buffers can also be combined with riparian zones in treating sheet flows and in stabilizing channel banks adjacent to major drainageways and receiving waters. • Vegetative and grass buffers can be interspersed with shrubs and trees to improve their aesthetics and to provide shading. • Are typically located adjacent to impervious areas. Limitations and When and Where NOT to use it: • Where concentrated runoff occurs. • May require the use of a porous pavement strip or another type of structure to achieve uniform sheet -flow conditions. • Provide only marginal pollutant removal. • Vegetative and grass buffers require follow-up structural BMPs to be provided. Construction Detail and Maintenance Requirements: • Vegetative and grass buffers should be incorporated into site drainage, street drainage, and master drainage planning. • Because their effectiveness depends on having an evenly distributed sheet flow over their surface, the size of the contributing area, and the associated volume of runoff have to be limited. • Flow can be directly accepted from an impervious area such as from parking lots and building roofs, provided the flow is distributed uniformly over the strip. • Should be protected from excessive pedestrian or vehicular traffic that can damage the grass cover and affect even sheet -flow distribution. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 23 Piceance Basin Natural Gas Development Program Doc. No.: PBSR-ALL-RGL-PMT-URS-06000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 24 Piceance Basin Natural Gas Development Program 12.0 WATERBARS Description: Waterbars are diversion ridges or berms and channels (consisting of compacted soil, loose rock, or gravel) that are built diagonally across a roadbed and serve to gather and shed surface runoff off the roadbed. Waterbars can divert runoff from an inside ditch to an adequate outfall and reduce runoff flow lengths and velocities. When and Where to use it: • Planting or application of seed for permanent revegetation and stabilization of disturbed soils. • Temporary protection of disturbed areas until permanent measures (e.g., vegetation) are installed. • Temporary protection of disturbed areas that must be re -disturbed following an extended period of inactivity. Limitations and When and Where NOT to use it: • The following factors may make the use of waterbars difficult or impossible: o Shallow bedrock depth. o Steep outfall slopes. o Steep roadway slopes (greater than 11 percent). o High traffic - high vehicle traffic can damage waterbars. • Drainage areas must be limited to less than 1.0 acre. • Waterbar spacing must be close enough to dissipate water flow energy. Construction Detail and Maintenance Requirements: • Angle waterbars across roadbeds in the down -gradient direction. Angles of 30 to 45 degrees are most effective. • Tie the upper end into the inside ditch's bank, when present. • The outlet should be open and extend far enough off the roadbed into a stable and undisturbed area. • The outlet should have a grade of 2 percent less than natural grade. • Follow the waterbar spacing guide below on long sloping roadbeds: o Road grade 2 percent - Spacing 250 feet. o Road grade 3 percent - Spacing 220 feet. o Road grade 4 percent - Spacing 190 feet. o Road grade 5 percent - Spacing 160 feet. o Road grade 6 percent - Spacing 144 feet. o Road grade 7 percent - Spacing 128 feet. o Road grade 8 percent - Spacing 112 feet. o Road grade 9 percent - Spacing 96 feet. o Road grade 10 percent - Spacing 80 feet. o Road grade 11 percent - Spacing 60 feet. • Signs alerting motorists of the waterbar should be installed in both directions. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 25 Piceance Basin Natural Gas Development Program Figure: Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 26 Piceance Basin Natural Gas Development Program 13.0 DIVERSION DITCHES/BERMS Description: A diversion ditch/berm is a small, temporary earthen channel or berm used to divert and convey runoff, usually to a sediment basin, trap, or pond. Depending on slope and anticipated flows, the diversion ditch may need to be lined with erosion control blankets, check dams, or plastic (temporarily). When and Where to use it: • To diverted runoff away from steep slopes. • A permanent or temporary diversion ditch, diversion berm or both should be installed above all steep slopes on the site that may receive concentrated or sheet flows. • Where steep cut slopes are planned near the site perimeters, a minimum of 6 feet between the property line and the top of the cut slope shall be reserved for the diversion ditch. • To capture runoff entering a site via sheet flow. • If the upstream disturbed drainage area exceeds 1.0 acre, a diversion ditch, diversion berm or both can be used to convey runoff to a sediment basin. Limitations and When and Where NOT to use it: • Concentrated runoff in the ditch or berm has increased erosion potential. • To alleviate erosion potential, diversion ditches and berms must be directed to sediment trapping devices, where erosion sediment can settle out of the runoff before being discharged to surface waters. • Examples of appropriate sediment trapping devices that might be used in conjunction with temporary diversion structures include sediment basins or other structures designed to allow sediment to be collected for proper disposal. Construction Detail and Maintenance Requirements: • Flow from diversion ditches/berms should be directed to a stream or drainage channel. • Diversion ditches/berms that have mild slopes may be unlined, whereas steeper ditches and rundowns must be lined with erosion control blanket (for moderate slopes), plastic (temporary installations only), or riprap. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 27 Piceance Basin Natural Gas Development Program Photograph: Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 28 Piceance Basin Natural Gas Development Program 14.0 GRAVEL SURFACING Description: Gravel surfacing simply involves covering exposed earth surfaces with gravel to prevent soil erosion from occurring. When and Where to use it: • On any exposed earthen areas, including: o Roadways. o Parking areas. o Laydown, staging, and storage areas. o Around foundations of structures, including where roof drains discharge. Limitations and When and Where NOT to use it: • Any location where concentrated storm -water flow will erode the gravel surface and/or underlying soil. • Gravel should not be used in place of riprap. Construction Detail and Maintenance Requirements: • Engineering design is required for gravel to be used on roadways, parking areas, and around foundations, including proper crowning features and to meet appropriate compaction requirements. • Selection of gravel size and depth should consider the use of the area to be covered, including factors such as types and frequency of traffic, duration of establishment (temporary or permanent), anticipated storm -water volumes (due to direct precipitation and surrounding area runon/runoff), etc. • Properly blended road gravel is required to produce good surfaces. Good gravel contains gravel, sand and fines (clay and silt). Good blends have a mixture of all three, with clay serving as the binder that helps hold the gravel in place. • Permeable fabric membranes/liners should be installed at the soil and gravel interface to prevent rutting and soil and mud from rising through the gravel due to traffic impacts. • Binders such as magnesium chloride may be applied to help fix and secure gravel surfaces in place. • The condition of gravel surfaces should be inspected regularly, after any major storms and at Least once a year to ensure that the surfaces and subsurfaces are sound and have not been subject to erosion. • Gravel should be replenished due to losses from compaction, drag -out, and spreading, especially in high -traffic areas. • Gravel may need to be replaced if soil or mud rises through or is tracked by traffic into gravel areas. • Gravel surfaces may need to be replaced and/or repaired following winter seasons, especially if surfaces are plowed for snow removal. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 29 Piceance Basin Natural Gas Development Program Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm-Water Management Plan Chevron North American Exploration and Production Company 30 Piceance Basin Natural Gas Development Program 15.0 SEDIMENT CONTROL BERMS Description: A temporary sediment barrier consisting of salvaged topsoil, surface soils and/or compacted vegetation pushed into a small berm at midslope locations or at the top or toe of fill slopes. A sediment control berm intercepts sediment -laden sheet flow runoff, allowing runoff to infiltrate and sediment to drop out of suspension. It also allows stockpiling of topsoil for future plating on slopes. When and Where to use it: • Below the toe of exposed and erodible slopes and soil stockpiles. • May be utilized in place of silt fence. • May be constructed in conjunction with topsoil salvage operations. • Soil may be reincorporated into adjacent slopes upon completion of final slope geometry. Limitations and When and Where NOT to use it: • May require additional BMPs where concentrated flows are involved. • Can create a temporary sedimentation pond on the upstream side of the berm. • Must be graded out prior to application of BMPs and seed to final slopes. • Additional BMPs are required where profile slopes exceed 3 percent. Construction Detail and Maintenance Requirements: • Berm soil shall be stabilized to prevent erosion. • Create a stabilized weir where runoff will pond and overtop berm. • Inspect for breaks and erosion in berms. • Repair as necessary. • Remove berm when up-slope area has been permanently stabilized. Grade area to blend in with adjacent ground. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 31 Piceance Basin Natural Gas Development Program Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 32 Piceance Basin Natural Gas Development Program 16.0 CHECK DAMS Description: Check dams are small, temporary or permanent dams constructed across a drainage ditch, swale or channel to reduce the velocity of concentrated flows and to trap sediment eroded from upstream. Check dams can be constructed out of rocks, gravel -filled sandbags or straw bales. When and Where to use it: • In open channels that receive flow from drainage between 1 and 10 acres. • In steeply sloped swales. • In swales that need protection during the establishment of grasses or prior to installation of a non -erodible lining. Limitations and When and Where NOT to use it: • In live streams. • In channels that receive flow from drainage areas greater than 10 acres. • In channels that will be overtopped by flow once the dams are constructed. Construction Detail and Maintenance Requirements: • Check dams can be constructed of rock, logs, sandbags, or straw bales: o When using rock or stone, the material diameter should be 2 to 15 inches. o Logs should have a diameter of 6 to 8 inches. • Dams should be installed with careful placement of the construction material. • All check dams should have a maximum height of 3 feet. • The center of the dam should be at least 6 inches lower than the edges to create a weir effect that helps to channel flows away from the banks and prevent erosion. • Additional stability can be achieved by implanting the dam material approximately 6 inches into the sides and bottom of the channel • When installing more than one check dam in a channel, outlet stabilization measures should be installed below the final dam in the series. • Because this area is likely to be vulnerable to further erosion, riprap, geotextile lining, or some other stabilization measure is recommended. • Check dams should be inspected after each storm event to ensure continued effectiveness. • During inspection, large debris, trash, and leaves should be removed. • If erosion or heavy flows cause the edges of a dam to fall to a height equal to or below the height of the center, repairs should be made immediately. • Accumulated sediment should be removed from the upstream side of a check dam when the sediment has reached a height of approximately one-half the original height of the dam (measured at the center). • All accumulated sediment should also be removed prior to removing a check dam. • Removal of a check dam should be completed only after the contributing drainage area has been completely stabilized. • Permanent vegetation should replace areas from which gravel, stone, logs, or other materials have been removed. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 33 Piceance Basin Natural Gas Development Program Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storrs -Water Management Plan Chevron North American Exploration and Production Company 34 Piceance Basin Natural Gas Development Program 17.0 DRAINAGE DIPS Description: Drainage dips are ridges or ridge -and -channels constructed diagonally across a sloping road or utility right-of-way that is subject to erosion to limit the accumulation of erosive volumes of water on roads by diverting surface runoff at designated intervals. They are similar in function to waterbars (also see Waterbar BMP). Drainage dips can be constructed as either: (1) Rolling Dips or (2) Broad -Based Dips. Broad -Base Dip drains water from the roadbed while allowing vehicles to maintain a safe traveling speed. A Rolling Dip is a broad-base dip with a water bar berm. Both types of dips gather water and divert it safely off the roadway. Dips provide cross drainage of inside ditches. When and Where to use it: • Drainage dips are gently sloping excavations running diagonally across the road surface, and are appropriate for winter use on unpaved roads and in areas prone to inundation due to culvert plugging. • Drainage dips are much easier to traverse and require less maintenance than waterbars. Limitations and When and Where NOT to use it: • Limiting factors include presence of shallow bedrock and excessive slopes (greater than 15 percent): o A Broad -Base Dip must only be used on roads where gradients are 8 percent or less. o Rolling Dips must be used on roads where gradients are 15 percent or less. • Drainage dips should not be used to handle live (constantly running) water. • Never install the drainage dips such that the discharge occurs onto unprotected fill slopes. • Drainage dips should not be constructed in areas of high speed vehicle travel. Construction Detail and Maintenance Requirements: • Install energy dissipaters, such as rip rap, or overside drains at outfall/outlet ends. • Use gravel to stabilize the diversion where significant vehicular traffic is anticipated. • Drainage dips should be built at an angle of 45 to 60 degrees from the roadway centerline. • The diversion should have a 2 percent minimum positive grade. • For drainage dips the height from channel bottom to the top of the settled ridge shall be 18 inches and the side slopes of the ridge shall be 2:1 or flatter where practicable. • Blend the berm to as gentle a slope as possible to ease traveling. • Follow the dip spacing guide below: o Road grade 2 percent - Spacing 300 feet. o Road grade 3 percent - Spacing 233 feet. o Road grade 4 percent - Spacing 200 feet. o Road grade 5 percent - Spacing 180 feet. o Road grade 6 percent - Spacing 167 feet. o Road grade 8 percent - Spacing 150 feet. o Road grade 9 percent - Spacing 144 feet. o Road grade 11 percent - Spacing 136 feet. o Road grade 13 percent - Spacing 131 feet. o Road grade 15 percent - Spacing 127 feet. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 35 Piceance Basin Natural Gas Development Program • The distance it takes for unrocked, unprotected running surface of a nearby road to develop a 1 inch rill is a rough measure of the appropriate spacing distance. • Signs alerting motorists to the dip should be installed in both directions. • Periodically inspect drainage dips: o Inspect after every heavy rainfall for erosion damage. o Immediately remove sediment from the flow area. o Check outlet areas and make timely repairs as needed. Figures: Blend Smoothy Rolling Dip 10 to 25• Above Grade Reverse Grade (3 to 8 percent) 8 inch Depth Below Grade Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 36 Piceance Basin Natural Gas Development Program Broad -Base Dip 20 ft 101025' �+ z Original Greda , .k- > - -, iri Reverse Grade (2 to 3 percent) Ouitiow 8 inch Depth Below Grade Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 37 Piceance Basin Natural Gas Development Program 18.0 EROSION CONTROL BLANKETS/MATS Description: Erosion control blankets/mats are geotextiles or filter fabrics that are used to stabilize soils, steep slopes and drainage channels. When and Where to use it: • In temporary and permanent swales. • To protect recently seeded slopes. • In drainageway channels. Limitations and When and Where NOT to use it: • Erosion control blankets/mats should not be used in swales with slopes greater than 5 percent or with storm -water velocities > 8 feet per second. • Erosion control blankets/mats should not be used in areas subject to scour from high flows (e.g. streambanks) unless designed by an engineer. • Permits shall be obtained prior to any streambank or shoreline installation of erosion control blankets/mats, including United States Army Corps of Engineers (USACE) Clean Water Act (CWA) Section 401/404 permits. • Blankets/mats manufactured with plastic netting shall be avoided. Installation and Maintenance Requirements: • Proper site preparation is essential to ensure complete contact of the protection matting with the soil: o Grade and shape area of installation. o Remove all rocks, clods, vegetative or other obstructions so that the installed blankets, or mats will have direct contact with the soil. o Prepare seedbed by loosening 2-3 inches (50-75 mm) of topsoil above final grade. o Seed area before blanket installation for erosion control and re -vegetation. (Seeding after mat installation is often specified for turf reinforcement application.) o U-shaped wire staples, metal geotextile stake pins, or triangular wooden stakes can be used to anchor mats to the ground surface: • Wire staples should be a minimum of 11 gauge. • Metal stake pins should be 3/16 inch diameter steel with a 1 1/2 inch steel washer at the head of the pin. • Wire staples and metal stakes should be driven flush to the soil surface. • All anchors should be 6-8 inches long and have sufficient ground penetration to resist pullout. • Longer anchors may be required for loose soils. • Begin at the top of the slope and anchor its blanket in a 6 inch deep x 6 inch wide trench. • Backfill trench and tamp earth firmly. • Unroll blanket downslope in the direction of the water flow. • The edges of adjacent parallel rolls must be overlapped 2-3 inches and be stapled every 3 feet. • When blankets must be spliced, place blankets end over end (shingle style) with 6 inch overlap. Staple through overlapped area, approximately 12 inches apart. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 38 Piceance Basin Natural Gas Development Program • Lay blankets loosely and maintain direct contact with the soil - do not stretch. • Blankets shall be stapled sufficiently to anchor blanket and maintain contact with the soil. • Staples shall be placed down the center and staggered with the staples placed along the edges. • Steep slopes, 1:1 to 2:1, require 2 staples per square yard. • Moderate slopes, 2:1 to 3:1, require 1-2 staples per square yard (1 staple 3' on center). • Gentle slopes require 1 staple per square yard. • All blankets and mats should be inspected periodically following installation. • Inspect installation after significant rainstorms to check for erosion and undermining and for fabric damage, looseness. • Any failure should be repaired immediately. Replacement of fabric sections may also be necessary. • If washout or breakage occurs, re -install the material after repairing the damage to the slope or drainageway. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 39 Piceance Basin Natural Gas Development Program Photographs: Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 40 Piceance Basin Natural Gas Development Program 19.0 SLOPE DRAINS Description: Slope drains are either flexible or rigid pipes that convey concentrated runoff from the top of a slope to a stable discharge point at the bottom of the slope. Slope drains can be either temporary or permanent depending on the method of installation and material used. When and Where to use it: • At the top of cut -and -fill slopes to convey storm -water down the slope. • Before a slope has been stabilized or before permanent drainage structures are ready for use. • In combination with other BMPs that have been used to concentrate flows, including temporary swales. Limitations and When and Where NOT to use it: • Slope drains should not be used for drainage areas larger than 5 acres. • Physical obstructions substantially reduce the effectiveness of the drain. • Other concerns are failures from overtopping because of inadequate pipe inlet capacity, and reduced diversion channel capacity and ridge height. Construction Detail and Maintenance Requirements: • The drain should consist of heavy-duty material manufactured for the purpose and have grommets for anchoring at a spacing of 10 feet or less. • Minimum slope drain diameters should be observed for varying drainage areas. • The entrance to the pipe should consist of a standard flared section of corrugated metal: o The corrugated metal pipe should have watertight joints at the ends. o The rest of the pipe is typically corrugated plastic or flexible tubing, although for flatter, shorter slopes, a polyethylene -lined channel is sometimes used. • The height of the diversion at the pipe should be the diameter of the pipe plus 0.5 foot. • The outlet should be located at a reinforced or erosion -resistant location. • Slope drains should be inspected after each rainfall to determine if capacity was exceeded or if blockages occurred. • Repairs should be made promptly. • Construction equipment and vehicular traffic must be rerouted around slope drains. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 41 Piceance Basin Natural Gas Development Program Photograph and Figure: Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 42 Piceance Basin Natural Gas Development Program 20.0 SLOPE STABILIZATION Description: Slope stabilization generally pertains to structures or other BMPs that stabilize slopes that cannot be stabilized with vegetation. These structures and BMPs may include gabions and retaining walls (also see Retaining Wall BMP). Some of these structures and BMPs are also used to stabilize stream banks. • Gabions are rectangular wire -mesh cages that are filled with rock and wired together to form a protective but permeable structure for slope stabilization and erosion control. • Gabions can be used as retaining walls to mechanically stabilize steep slopes, or for revetments, weirs, channel linings, culvert headwalls, and culvert outlet aprons. They are particularly useful where seepage is anticipated. When and Where to use it: • Slope stabilization structures or other BMPs should be installed prior to or immediately after disturbing erodible soils. • Slope stabilization should be applied in areas where there is active or foreseeable erosion of the soils adjacent to a watercourse or wetland, and/or on steep slopes. • Note that the construction and installation of these structures should not result in encroachment into the watercourse or wetland. • The type of slope stabilization method used will vary depending upon the soils, slope of the land, groundwater characteristics, and the climatic conditions of the area. • Their use is very important in areas where there are steep slopes, highly erodible soils, and where conditions can significantly increase or create erosion (i.e. areas of flash floods, strong winds and lake shorelines). • Special consideration should be given to the design and use of structures that will be susceptible to the forces of ice movement. Ice action has been shown to weaken, dislocate, and destroy improperly designed and installed structures. Limitations and When and Where NOT to use it: Slope stabilization should not be used where other BMPs that achieve stabilization with vegetation, such as mulching, can be applied effectively. Construction Detail and Maintenance Requirements: • Gabions: o Construction plans and specifications should be prepared by professionals familiar with the use of gabions. o The structure must be able to handle expected storm and flood conditions. o On streambank applications, the foundation is an important design feature of the structure. Consider the potential for the stream to erode the sides and bottom of the channel and make sure the gabions will be supported properly. o The gabion structure must be securely "keyed" into the foundation and abutment surfaces. The rock filling holds the gabions in place by gravity, but tie -backs may be used if conditions warrant additional structural strength. o Gabions are usually placed on a filter blanket (gravel layer of filter cloth) or both. o Gabions should be fabricated in such a manner that the sides, ends, Lids, and diaphragms can be assembled at the construction site into a rectangular basket of required sizes. o Gabions should be of single unit construction -- the base, ends, and sides should either be woven into a single unit or one edge of these members connected to the Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 43 Piceance Basin Natural Gas Development Program base section of the gabion in such a manner that strength and flexibility at the point of connection is at least equal to that of the mesh. o Where the length of the gabion exceeds its horizontal width, the gabion should be equally divided by diaphragms, of the same mesh and gage as the body of the gabions, into cells whose length does not exceed the horizontal width. o The gabion should be furnished with the necessary diaphragms secured in proper position on the base section in such a manner that no additional tying at this juncture will be necessary. o All perimeter edges should be securely selvedged or bound so that the joints formed by tying the selvedges have the same strength as the body of the mesh. o The fill material for the wire gabions should be rock ranging in size from a minimum of 4 inches to a maximum of 8 inches, both measured in the greatest dimension. Rock should be sound, durable, and well graded. • All slope stabilization structures and other BMPs should be free of sharp edges and protruding metals. • All structures require a site visit to determine the appropriate structure. During a site visit: o Determine the soil texture and its inherent stability. o Determine the normal and storm surge water elevations. o Measure the length and (where appropriate) height of the area. o Consider the elevation of the proposed location for the new structure in comparison to the elevation of the existing shoreline. • Areas up-slope of these structures and other BMPs should be stabilized with vegetation by revegetation (seeding/sodding) and mulching (also see Revegetation and Mulching BMPs). • In some instances, diversions can be used to divert water away from these structures while they are being developed. • Geotextile Filters are often used under these structures to filter sediment. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 44 Piceance Basin Natural Gas Development Program 21.0 MULCHING Description: Mulching is used to temporarily stabilize soils by securely applying materials such as grass, hay, woodchips or wood fibers to the soil's surface. Mulching protects the soil from raindrop impact and reduces the velocity of overland runoff. Mulch also aids in the growth of temporary seeding by holding seeds and topsoil in place, retaining moisture, and insulating against extreme temperatures. When and Where to use it: • On steep slopes and critical areas such as waterways, mulch matting is used with netting or anchoring to hold it in place. • Mulches can be used on seeded and planted areas where slopes are steeper than 2:1 or where sensitive seedlings require insulation from extreme temperatures or moisture retention. • All disturbed areas and stockpiles shall be mulched within 21 days after final grade is reached. • Disturbed areas and stockpiles which are not at final grade but will remain dormant for longer than 30 days shall also be mulched within 21 days after interim grading. • An area that is going to remain in an interim state for more than 60 days shall also be seeded. • Mulching is always to be used when applying temporary or permanent seeding. • Mulching is often used when temporary seeding cannot be used due to the season or climate. Limitations and When and Where NOT to use it: • Mulching is not a preferred BMP in areas that will involve paving, building, or utility construction within 21 days after final grade is reached. • Mulching, matting, and netting might delay seed germination because the cover changes soil surface temperatures. • The mulches themselves are subject to erosion and may be washed away in a large storm. • Maintenance is necessary to ensure that mulches provide effective erosion control. Application Techniques and Maintenance Requirements: • When possible, organic mulches should be used for erosion control and plant material establishment. • Suggested materials include loose straw, netting, wood cellulose, or agricultural silage. • All materials should be free of seed, and loose hay or straw should be anchored by applying tackifier, stapling netting over the top, or crimping with a mulch crimping tool. • Materials that are heavy enough to stay in place (for example, gravel or bark or wood chips on flat slopes) do not need anchoring. • Other examples include hydraulic mulch products with 100 -percent post -consumer paper content, yard trimming composts, and wood mulch from recycled stumps and tree parts. • Inorganic mulches such as pea gravel or crushed granite can be used in unvegetated areas. • Mulches may or may not require a binder, netting, or tacking. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Stam -Water Management Plan Chevron North American Exploration and Production Company 45 Piceance Basin Natural Gas Development Program • Effective use of netting and matting material requires firm, continuous contact between the materials and the soil. If there is no contact, the material will not hold the soil and erosion will occur underneath the material. • Grading is not necessary before mulching. • There must be adequate coverage to prevent erosion, washout, and poor plant establishment. • If an appropriate tacking agent is not applied, or is applied in insufficient amounts, mulch may be lost to wind and runoff. • The channel grade and liner must be appropriate for the amount of runoff, or resulting erosion will occur in the channel bottom. • Hydromulch should be applied in spring, summer, or fall to prevent deterioration of mulch before plants can become established. • Guidelines for installing mulches, typical mulching materials, and application rates are as follows: o Straw: • Rate per Acre: 1-2 Tons. • Requirements: Dry, unchopped, unweathered; avoid weeds. • Notes : Spread by hand or machine; must be tacked or tied down. o Wood Fiber or Wood Cellulose: • Rate per Acre: t/ - 1 ton. • Notes: Use with hydroseeder; may be used to tack straw. Do not use in hot, dry weather. o Wood Chips: • Rate per Acre: 5 - 6 tons. • Requirements: Air dry. Add fertilizer, 12 Ib/ton. ▪ Notes: Apply with blower, chip handler, or by hand. Not for fine turf areas. o Bark: • Rate per Acre: 35 cubic yard. • Requirements: Air dry, shredded, or hammermilled, or chips. • Notes: Apply with mulch blower, chip handler, or by hand. Do not use asphalt tack. o Nets and Mats: • Rate per Acre: Jute net. • Requirements: Cover area. • Notes : Heavy, uniform; woven of single jute yarn. Used with organic mulch. Withstands water flow. o Excelsior (Wood Fiber) Mat: • Rate per Acre: Cover area. o Fiberglass Roving: • Rate per Acre: th - I ton. ▪ Requirements: Continuous fibers of drawn glass bound together with a non-toxic agent. • Notes: Apply with compressed air ejector. Tack with emulsified asphalt at a rate of 25 - 35 gallons/1000 foot. • Mulched areas should be inspected frequently to identify areas where mulch has loosened or been removed, especially after rainstorms. • Such areas should be reseeded (if necessary) and the mulch cover replaced immediately. • Mulch binders should be applied at rates recommended by the manufacturer. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 46 Piceance Basin Natural Gas Development Program • If washout, breakage, or erosion occurs, surfaces should be repaired, reseeded, and remulched, and new netting should be installed. • Inspections should be continued until vegetation is firmly established. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 47 Piceance Basin Natural Gas Development Program 22.0 CULVERTS Description: Culverts consist of concrete or metal pipe or structures (box culverts) that are installed to conduct intermittent or constant flow around obstacles or under roadways or other related infrastructure (utilities such as pipelines, electrical lines, water, sewer, etc.). When and Where to use it: • To conduct flow around obstacles or under roadways or other related infrastructure. • Can be used to handle intermittent or constant, manmade or natural flows. Limitations and When and Where NOT to use it: For temporary culvert crossings, pipe class/size, and minimum cover, etc. should be sized to ensure that the culverts will convey the flow of the watercourse and bear the loads associated with the type of vehicles that may use the crossing. Construction Detail and Maintenance Requirements: • Confirm that all related stream permitting is obtained prior to installing temporary stream crossings and that all work will be in compliance with such permitting — including USACE CWA Section 401/404 permitting requirements. • Ford stream crossings should be lined with filter fabric and then layered with a minimum 6 -inch layer of 11/2" inch diameter rock. • Sediment accumulated upstream of stream crossings should be removed when the sediment depth is within 6 -inches of the crest (ford crossing) or greater than an average depth of 12 -inches (culvert crossing). Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 48 Piceance Basin Natural Gas Development Program Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storrs -Water Management Plan Chevron North American Exploration and Production Company 49 Piceance Basin Natural Gas Development Program 23.0 CULVERT INLET AND OUTLET PROTECTION Description: Protective measure BMPs installed to prevent erosion, scour, and undercutting at culvert inlet and outlets. When and Where to use it: • At culvert installation inlets and outlets. • Typically consists of other BMPs installed in conjunction with typical culverts, in particular riprap. Limitations and When and Where NOT to use it: None. Construction Detail and Maintenance Requirements: • Confirm that all related stream permitting is obtained prior to installing temporary stream crossings and that all work will be in compliance with such permitting — including USACE CWA Section 401/404 permitting requirements. • Use of recycled concrete is not an acceptable substitute for rock. • Sediment accumulated upstream of stream crossings should be removed when the sediment depth is within 6 -inches of the crest (ford crossing) or greater than an average depth of 12 -inches (culvert crossing). Photographs and Figures: See pictures and figures for riprap. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 50 Piceance Basin Natural Gas Development Program 24.0 REVEGETATION Description: Revegetation typically consists of planting plants or applying a mixture of fiber, seed, and fertilizer that protect exposed soils from erosion by water and wind. Revegetation should be conducted as quickly as possible in areas where work has been completed or when there will be no work for an extended period of time. Site planning and phasing should include measures to ensure that disturbed areas are revegetated within fourteen (14) calendar days after final grading, earth disturbance activities have been completed or when work is suspended for longer than thirty (30) days. Revegetated areas should be protected with crimped straw mulch, or erosion control blankets. When and Where to use it: • Planting or application of seed for permanent revegetation and stabilization of disturbed soils. • Temporary protection of disturbed areas until permanent measures (e.g., vegetation) are installed. • Temporary protection of disturbed areas that must be re -disturbed following an extended period of inactivity. Limitations and When and Where NOT to use it: • Straw mulching may be necessary in addition to revegetation in order to properly establish vegetation. • Steep slopes may be difficult to protect and establish with revegetation. • Dry or cold weather will affect revegetation establishment. Construction Detail and Maintenance Requirements: • Site conditions must be evaluated prior to determining suitable species selection and application rates. • Attributes such as soil types, topography, local climate and season, maintenance requirements, proximity of sensitive areas (e.g., live streams), and existing native vegetation types should be considered. • All plants and seeds to be used shall be in conformance with requirements of the project specifications. • Revegetation should only be conducted after appropriate seedbed and soil preparations have been made to ensure the soil is conducive to plant growth. • This may include soil amendments and/or grading and tilling. • Revegetated areas shall be covered with crimped straw mulch or erosion control blankets to protect plants and the seedbed and facilitate root growth and germination. • Revegetated areas shall be inspected to verify germination, vegetative growth, and adequate ground cover. • Revegetated areas that fail to establish or are disturbed should be re -planted or seeded as appropriate. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Han Chevron North American Exploration and Production Company 51 Piceance Basin Natural Gas Development Program Photograph: Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 52 Piceance Basin Natural Gas Development Program 25.0 TURNOUTS Description: Water turnouts can be a ditch, trench, or other conveyance used to divert storm - water runoff away from a road surface or adjacent ditch. The turnout, which can be the width of a backhoe bucket or a bulldozer blade, carries water into undisturbed areas of vegetation to both dissipate energy and disperse water flow to the forest floor. When and Where to use it: • The use of water turnouts is often dependent on gradient of the property and availability of suitable outlets. • Water turnouts should be spaced at a distance to provide good road drainage thus avoiding water pooling which can lead to soil compaction, souping, or rutting. • A water turnout can have a secondary application of functioning as a minor sediment trap, therefore, maintenance is important to ensure the turnout is neither subject to erosion itself from excessive runoff events or sedimentation to the point of becoming nonfunctional. • Most importantly, water turnouts must not empty directly into streams or other water channels (i.e., drainage ways, ditches, channalized streams, etc.) leading directly to streams and other waters. Limitations and When and Where NOT to use it: None. Construction Detail and Maintenance Requirements: • Water turnouts should intersect a ditch line at the same depth and be outsloped 1-3 percent. • On sloping roads, turnouts should be 30-45 degrees downslope.. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 53 Piceance Basin Natural Gas Development Program Figure: Water Turnout ® To divert water water away front road and carry it into undisturbed areas • Should not empty directly into adjacent drainages or stream channel. • At outlet end of turnout, spread, retain or filter run-off water with use of rip rap, brush, etc. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 54 Piceance Basin Natural Gas Development Program 26.0 STABILIZED ENTRANCE/EXIT Description: A temporary stabilized vehicular entrance should be established at all points where traffic will enter and exit the site. A stabilized construction entrance/exit reduces or eliminates the tracking of sediment onto public right-of-way, streets, or parking areas where it can be washed into local streams or become airborne pollution due to wind affects. When and Where to use it: • Wherever traffic will be entering or leaving a construction site. • Entrances should be constructed on level ground. • Site specific, conditions will dictate need. Limitations and When and Where NOT to use it: • Entrances must be planned and reviewed as part of the project traffic control plan. • Some soil may still be deposited from vehicle tires onto paved surfaces and require subsequent cleanup. • To further reduce the chance of these sediments polluting storm water runoff, sweeping of the paved area adjacent to the stabilized site entrance is recommended. Construction Detail and Maintenance Requirements: • Entrances must be properly graded to prevent runoff from leaving the site. • Entrances should drain to a sediment trap or sediment basin. • Design stabilized entrance/exit to support the heaviest vehicles and equipment that will use it. • Place aggregate over geotextile fabric to prevent sediment from the base material from migrating into the aggregate. • Aggregate should be angular, fractured rock. • Aggregate should be 12 inches deep, 3 to 6 inches in size and 50 feet long. • Gravel mat shall be replaced by top dressing with additional stone when surface voids are no longer visible. • All sediment deposited on paved roadways must be removed within 24 hours. • The gravel and filter fabric must be removed upon completion of the construction and disturbed soil areas resulting from removal shall be permanently stabilized. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 55 Piceance Basin Natural Gas Development Program Photograph: Stabilized construction entrances allow dirt to be removedfrom tire treadsand collected as trucks leave construction sites Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 56 Piceance Basin Natural Gas Development Program 27.0 RETAINING WALLS Description: Retaining walls are constructed against a slope or stream bank to prevent slope erosion or slope failure, or undercutting of streambanks. Retaining wall may be constructed of concrete, concrete masonry, rock, wood planking or railroad ties, and metal bins. When and Where to use it: For slope protection or stabilization under extreme conditions or to protect erodible, unstable stream banks. Limitations and When and Where NOT to use it: • Retaining walls should be considered a permanent measure only. Cost and site-specific design requirements limit their use to situations where other stabilization measures would be ineffective. • Native rock retaining walls have a maximum height of about 6.5 feet. • Redwood retaining walls require a firm foundation to anchor the wall. • Wood treated with creosote or other chemicals to retard decay may leach out and cause toxic effects. Treated railroad ties should not be used along sensitive streams for instance. Construction Detail and Maintenance Requirements: • Retaining walls require a site-specific design. • Wall heights, requirements for drainage, and suitable materials must be determined through on-site inspections. • All types of retaining walls should conform to local building codes and ordinances. • Plans and specifications should be prepared by professional engineers for most installations. • Retaining walls must be inspected periodically on regular intervals to detect signs of structural failure, and to check for damage caused by subsurface drainage or material sloughing. • In stream bank installations should be inspected for signs of undercutting and other instability. • All repairs should be made promptly, as needed. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 57 Piceance Basin Natural Gas Development Program 28.0 CONCRETE WASHOUT FACILITIES Description: Concrete washout facilities are used to prevent or reduce the discharge of pollutants to storm -water from concrete waste by conducting washout offsite, performing onsite washout in a designated area, and training employee and subcontractors. When and Where to use it: • Concrete washout facilities are used on construction projects where: o Concrete is used as a construction material or where concrete dust and debris result form demolition activities. o Slurries containing portland cement concrete or asphalt concrete are generated, such as from saw cutting, coring, grinding, grooving, and hydro -concrete demolition. o Concrete trucks and other concrete -coated equipment are washed onsite. o Mortar -mixing stations exist. Limitations and When and Where NOT to use it: Offsite washout of concrete wastes may not always be possible. Construction Detail and Maintenance Requirements: • Discuss the concrete management techniques described in this BMP (such as handling of concrete waste and washout) with the ready -mix concrete supplier before any deliveries are made. • Incorporate requirements for concrete waste management into material supplier and subcontractor agreements. • Do not allow excess concrete to be dumped onsite, except in designated areas. • For onsite washout: o Locate washout area at least 50 feet from storm drains, open ditches, or water bodies. o Avoid creating runoff by draining water to a bermed or level area when washing concrete to remove fine particles and expose the aggregate. o Post a sign adjacent to each washout facility to inform concrete equipment operators to utilize the proper facilities. o Do not allow runoff from this area by constructing a temporary pit or bermed area large enough for liquid and solid waste. o Only concrete from mixer truck chutes should be washed into concrete wash out. o Once concrete wastes are washed into the designated area and allowed to harden, the concrete should be broken up, removed, and disposed of. • Education: o Educate employees, subcontractors, and suppliers on the concrete waste management techniques described herein. o Arrange for contractor's superintendent or representative to oversee and enforce concrete waste management procedures. • Inspection and Maintenance: o Inspect and verify that activity—based BMPs are in place prior to the commencement of associated activities. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 58 Piceance Basin Natural Gas Development Program o While activities associated with the BMP are under way, inspect weekly during the rainy season and on two-week intervals in the non -rainy season to verify continued BMP implementation. o Temporary concrete washout facilities should be maintained to provide adequate holding capacity with a minimum freeboard of 4 inches for above grade facilities and 12 inches for below grade facilities. o Maintaining temporary concrete washout facilities should include removing and disposing of hardened concrete and retuming the facilities to a functional condition. o Hardened concrete materials should be removed and disposed of. o Washout facilities must be cleaned, or new facilities must be constructed and ready for use once the washout is 75 percent full. Photographs: Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 59 Piceance Basin Natural Gas Development Program Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Stonn-Water Management Plan Chevron North American Exploration and Production Company 60 Piceance Basin Natural Gas Development Program 29.0 SANITARY/SEPTIC (PORT -O -LET) WASTE MANAGEMENT Description: Proper sanitary and septic waste management prevents the discharge of pollutants to storm -water from sanitary and septic waste by providing convenient, well-maintained facilities, and arranging for regular service and disposal. When and Where to use it: Sanitary septic waste management practices are suitable for use at all construction sites that use temporary or portable sanitary and septic waste systems. Limitations and When and Where NOT to use it: None. Construction Detail and Maintenance Requirements: • Sanitary or septic wastes should be treated or disposed of in accordance with state and local requirements. In many cases, one contract with a local facility supplier will be all that it takes to make sure sanitary wastes are properly disposed. • Storage and Disposal Procedures: o Temporary sanitary facilities should be located away from drainage facilities, watercourses, and from traffic circulation. o Temporary sanitary facilities should be secured to prevent overtuming due to high winds or risk of high winds. o Only reputable, licensed sanitary and septic waste haulers should be used. o Sanitary facilities should be located in a convenient location. o Untreated raw wastewater should never be discharged or buried. o Regular waste collection by a licensed hauler should be arranged before facilities overflow. • Education: o Educate employees, subcontractors, and suppliers on sanitary and septic waste storage and disposal procedures. o Educate employees, subcontractors, and suppliers of potential dangers to humans and the environment from sanitary and septic wastes. o Instruct employees, subcontractors, and suppliers in identification of sanitary and septic waste. o Hold regular meetings to discuss and reinforce disposal procedures (incorporate into regular safety meetings). o Establish a continuing education program to indoctrinate new employees. • Inspection and Maintenance: o Inspect and verify that activity—based BMPs are in place prior to the commencement of associated activities. o While activities associated with the BMP are under way, inspect weekly during the rainy season and on two-week intervals in the non -rainy season to verify continued BMP implementation. o Arrange for regular waste collection. o If high winds are expected, portable sanitary facilities must be secured with spikes or weighed down to prevent over turning. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 61 Piceance Basin Natural Gas Development Program Photograph and Figure: NATIONAL te «-t beet F4XrMNf CONTAINMENT EARTHEN BERM OR SAND BAGS 1' X 1' Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 62 Piceance Basin Natural Gas Development Program 30.0 INLET PROTECTION Description: Inlet protection is a sediment control barrier formed around a storm drain inlet. A number of alternative inlet protection designs are available, including: • Silt fence inlet protection. • Straw bale barrier inlet protection. • Block and gravel bag inlet protection. • Curb socks and sandbag inlet protection. When and Where to use it: Application of inlet protection differs by design, as follows: • Filter fabric and straw bale inlet protection are used for area inlets (not located within streets). • Block and gravel bag curb inlet protection is used for street inlets in sumps. • Curb sock protection is used for street inlets in sumps or on continuous grade. Limitations and When and Where NOT to use it: • Filter fabric and straw bale inlet protection cannot be used for drain inlets that are paved because these designs require excavation and/or staking of materials. • Block and gravel bag inlet protection is not recommended for continuous grade inlets due to concerns about damage from bypassed flow. Construction Detail and Maintenance Requirements: • These controls should be installed before any soil disturbance in the drainage area. • Fabric inlet protection should be staked close to the inlet to prevent overflow on unprotected soils. • For sandbags: o Sandbags shall be filled with 3/4 inch drain rock or 1/4 inch pea gravel. o Several layers of bags should be overlapped and packed tightly. o Leave a one -sandbag gap in the top row to act as a spillway. • Inspect and clean barriers during and after each significant storm and remove sediment from behind structures after every storm. • Any sediment and gravel shall be immediately removed from the traveled way of roads. • The removed sediment shall be placed where it cannot enter a storm drain, stream, or be transported off site. • If the gravel becomes clogged with sediment, it must be carefully removed from the inlet and either cleared or replaced. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 63 Piceance Basin Natural Gas Development Program Photographs: Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 64 Piceance Basin Natural Gas Development Program Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Chevron North American Exploration and Production Company 65 Skinner Ridge Storm -Water Management Plan Piceance Basin Natural Gas Development Program Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm-Water Management Plan Chevron North American Exploration and Production Company 66 Piceance Basin Natural Gas Development Program Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm-Water Management Plan Chevron North American Exploration and Production Company 67 Piceance Basin Natural Gas Development Program Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm-Water Management Plan Chevron North American Exploration and Production Company 68 Piceance Basin Natural Gas Development Program Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm-Water Management Plan Chevron North American Exploration and Production Company 69 Piceance Basin Natural Gas Development Program 31.0 TEMPORARY SEDIMENT BASINS Description: A temporary sediment basin detains sediment -laden runoff long enough to allow much of the sediment to settle out. Sediment basins are constructed by excavation and/or by placing an earthen embankment across a low area or drainage Swale. Basins can be designed to maintain a permanent pool or to drain completely dry through a controlled outlet structure. When and Where to use it: • Required in disturbed areas draining more than one acre. • Where there is sufficient space and appropriate topography. • In areas that allow access for maintenance and sediment removal. • Positioned so that it captures sediment from the entire upstream disturbed area. • Where a permanent detention basin is planned for the site. Limitations and When and Where NOT to use it: Sediment basins are not to be installed in active streams. Construction Detail and Maintenance Requirements: • Potential sites for sediment basins should be investigated during the initial site evaluation. • Basins should be constructed before any grading takes place within the drainage area. • For structures that will be permanent, the design of the basin should be completed by a qualified professional engineer experienced in the design of dams. • Sediment basins with rock dams should be limited to a drainage area of 50 acres. • Rock dam height should be limited to 8 feet with a minimum top width of 5 feet. • Side slopes for rock dams should be no steeper than 2:1 on the basin side of the structure and 3:1 on the outlet side. • The basin side of the rock dam should be covered with fine gravel from top to bottom for a minimum of 1 foot to slow the drainage rate from the pool that forms and allow time for sediments to settle. • The detention time should be at least 8 hours. • Sediment basins with earthen embankments should be outfitted with a dewatering pipe and riser set just above the sediment removal cutoff level. • The riser pipe should be located at the deepest point of the basin and extend no farther than 1 foot below the level of the earthen dam. • A water -permeable cover should be placed over the primary dewatering riser pipe to prevent trash and debris from entering and clogging the spillway. • To provide an additional path for water to enter the primary spillway, secondary dewatering holes can be drilled near the base of the riser pipe, provided the holes are protected with gravel to prevent sediment from entering the spillway piping. • In all cases, such structures should be designed by an appropriate professional based on local hydrologic, hydraulic, topographic, and sediment conditions. • Routine inspection and maintenance of sediment basins is essential to their continued effectiveness. • Basins should be inspected after each storm event to ensure proper drainage from the collection pool to determine the need for structural repairs. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 70 Piceance Basin Natural Gas Development Program • Erosion from the earthen embankment or stones moved from rock dams should be replaced immediately. • Sediment basins must be located in an area that is easily accessible to maintenance crews for removal of accumulated sediment. • Sediment should be removed from the basin when its storage capacity has reached approximately 50 percent. • Trash and debris from around dewatering devices should be removed promptly after rainfall events. Doc. No.: PBSR-ALL-RGL-PMT-URS-00000-00002-00, Rev. F Skinner Ridge Storm -Water Management Plan Chevron North American Exploration and Production Company 71 Piceance Basin Natural Gas Development Program Appendix B - Down -Hole Chemical List - Frac Operations ti*.:liChemical^Manufacturer a a=:- 1 0 r 7 a x 0 r 7 a x 0 r > a x 0 r > a x 0 r > a x 0 r > a mix' 0 r > a 0 r a 0 r a 0 r a x ;,P D 0 a u 1 c '1 t t PI Additive, ammonium chloride, zirconium complex Acid, inorganic acid Acid, inorganic acid Acid, inorganic acid Corrosion inhibitor, chloromethylnaphthalene Surfactant, 1,2, 4 Trimethylbezene Friction reducer, hydrotreated light petroleum distallate Surfactant, isoprpanol P o m Biocide -- �; �;�;awep,lanpo�dzSaSW�;, Clayfax II Material 10% Hydrochloric acid 7.5% Hydrochloric acid 15% Hydrochloric acid 2 v o vi x ILosurf - 300M mai N LL E yM(O CD CO CO Stormwater Inspection Form (Light/Heavy Industry) Colorado Stormwater Program (WQCD-B2-PE) Phone (303) 692-3575 Fax (303) 782-0390 Email: cdpheWQStorm@cdphe.state.co.us General Information Name of facility: CDPS#: CO Facility Information City: County: Address/Directions: Name(s) of Onsite Representative(s): phone: ( ) Permittee (If not permitted, Owner or Operator) Company Name: Name of Responsible Official: Title of Responsible Official: phone: ( ) Address: Inspector(s): Persons present: Inspecting Agency: Date conducted: / / Pictures Taken? Yes No Records Copy of SWMP confirmed on site? Yes SWMP Review: 1. Industrial activity description as required in the permit? Yes Notes: No No 2. Site map as required in the permit? Yes Notes: No 3. Stormwater Management Controls: a. SWMP administrator as required in the permit? Yes Notes: No b. Identifying potential pollutant sources and BMPs? Yes Notes: No c. Sampling information as required in the permit? Yes Notes: No d. Preventive maintenance as required in the permit? Yes Notes: No e. Good housekeeping as required in the permit? Yes Notes: No f. Spill prevention and response procedures as required in the permit? Yes Notes: No g. Employee training as required in the permit? Yes Notes: No h. Identifications of discharges other than stormwater as required in the permit? Yes Notes: No 4. Comprehensive inspections as required in the permit Yes Notes: No 5. Consistency with other plans as required in the permit Yes Notes: No Inspection records kept? Yes Inspections conducted as required in the permit? Yes Notes: No No Stormwater Inspection Form (Licht/Heavy Industry) Page 2 Site Inspection BMPs implemented for stormwater diversion around potential pollution sources? Notes: Yes No BMPs implemented for materials handling, spill prevention, and spill cleanup? Notes: Yes No BMPs implemented for sediment and erosion prevention? Notes: Yes No BMPs implemented for good housekeeping? Notes: Yes No BMPs implemented for inspection and maintenance of stormwater management devices? Notes: Yes No BMPs implemented for training all employees on stormwater management? Notes: Yes No Evidence of offsite transport of sediment or other pollutants? Notes: Yes No Evidence of offsite transport of sediment or other pollutants reaching state waters? Notes: Yes No Evidence of discharges other than stormwater? Notes: Yes No Comments: Site -Specific Storm -Water /Soil Management Plan Page 1/5 Site Name: Central Production Facility/Temporary Storage Area Date of Plan: June 26, 2008, Rev. 1 1. Site Activity / Description Background Information: Information provided in this document is intended to supplement the existing Skinner Ridge Storm Water Management Plan. This document specifically addresses the requirements for the Central Production Facility. Site Purpose: A 50 MMscf compression / drying facility known as the Central Production Facility (CPF) will be constructed in stages near the confluence of Tom Creek and Clear Creek in Garfield County, CO. The CPF purpose is to dry and compress raw natural gas coming from the well field for delivery to regional pipelines. CPF operations will include transfer / compression of natural gas, removal / storage / transfer of produced water (water entrained in the raw gas stream), and removal / storage of condensate (mixture of low-density hydrocarbons entrained in the raw gas stream), and emission control. The facility is equipped with all the required safety and control systems. A flare stack will be installed along the eastern edge of the facility for start up operations and to handle any possible system upsets. Initial fluid separation will occur at early production system well pads (four new and three existing pads) that will be connected to the CPF via pipelines. Eight- to ten - inch pipelines will be used to gather the gas and four - inch pipelines will be used to gather the liquids. Total length of these pipelines will be about three miles. Well pads will be equipped with gas and liquid line scrapper (pig) launchers to clean the interior of these pipelines. Storm -water controls for these pipelines will be addressed in a separate document. A temporary storage area will be constructed on the west side of the main CPF pad. This area will be used to store earthmoving equipment, vehicles, construction materials, CPF equipment, pipeline, and miscellaneous general storage. Up to seven construction trailers and a TBD number of Connex / trailer storage containers will be placed in this area. The area also may be used to store a limited amount of fuel (<1,000 gallons) for construction equipment. All fuel storage will be equipped with the required secondary containment and conform to the site Spill Control and Counter Measures (SPCC) plan and associated safety requirements. This area will be abandoned when the CPF becomes operation due to the proximity of the flare stack. Site Location: The proposed facility will be located about 2.5 miles north northwest of the end of County Road (CR) 211 in the Clear Creek drainage (see Figure 1). The site can be accessed from Interstate 70, exit 62, by traveling north on local Road 45N. Road 45N north of De Beque, Colorado, is also known as Roan Creek Road/Drive and CR 204. The intersection of CR 211 and CR 204 is located about 12.5 miles north northwest of De Beque. Traveling north of the intersection about 4.5 miles, one reaches the end of CR 211, where a gated fence is encountered. An existing ranch road continues north onto Chevron fee land. Site Area/Disturbed Area: The initial disturbance for the construction and installation of the CPF is about 12 acres, with a permanent disturbance of about 8.5 acres (includes access roads and flare radius). Borrow material will be obtained from an on-site, permitted material mine. A general coordinate for the facility is 39°34'17.94"N latitude, 108°20'43.51"W longitude NAD 83 / WGS-84. General Topography: The CPF site lies in the Douglas -Plateau area. It consists of narrow foothills valleys, high rolling plateaus dissected by steep canyons, narrow mountain valleys, and high mountains. The area of exploration and production is mostly rangeland, with the primary limitations for grazing being steep slopes, short growing season, rockiness, and limited water. Geology: The underlying rocks are relatively late geologic age, mostly from the Cretaceous or Tertiary periods. They range from hundreds to thousands of feet in thickness and are generally tilted and unfolded. The formations commonly extend of broad areas. Property elevations vary from 5,800 ft (valley floor) to 8,500 ft (Roan Plateau). The Roan Plateau extends north into Rio Blanco County, and surrounds the Skinner Ridge development site. The Roan Plateau consists of the generally stable Green River Formation. Site Solis / Slopes: The dominant soil type is Cumulic Haploborolls, a soil series that is placed in the hydrologic soil group B. Cumulic Haploborolls soils having a moderate infiltration rate when thoroughly wet and consist chiefly of moderately deep or deep, moderately well drained to well drained soils with moderately fine to moderately coarse texture. These are alluvial soils with a moderate rate of water transmission. CPF area slopes range from to 1 to 4 percent. Information published by the National Resource Conservation Service (NRCS) describes the area soils as deep, well to poorly drained, formed in alluvium dominated mostly by the Green River and Wasatch shale formations. The NRCS information details a surface layer of dark grayish brown gravelly sandy clay loam about eight inches thick, followed by about 12 - inches of grayish brown very channery sandy clay loam. The subsoil is grayish brown clay loam about eight inches thick The upper part of the substratum is light brownish gray very gravelly loamy sand about 16 inches thick, while the lower part of the substratum to a depth of greater than 60 inches is a yellow very gravelly sand. In some areas the surface layer is loam or silty clay loam. Permeability is moderate to moderately slow. And runoff is generally slow; the hazard of water erosion is slight. These soils are subject to brief periods of flooding as a result of snowmelt and intense thunderstorms in the spring and summer. Perliminary geotechnical information indicate that the site is covered with about one foot of topsoil (that will be stockpiled) with about 10 feet of underlying medium to stiff clay with shale fragments (Unified Soil Classification System soil classification CL / SH). The erodability of the soil based upon Revised Universal Soil Loss Equation Version 2 (RUSLE2) is 0.17 for the Kf Site -Specific Storm -Water / Soil Management Pian Page 2/5 Site Name: Central Production Facility/Temporary Storage Area Date of Plan: June 26, 2008, Rev. 1 (the susceptibility of the surface horizon to sheet and rill erosion by water) and 3 for the T factor (the estimate of the maximum average annual rate of soil erosion by wind and/or water that can occur without affecting crop productivity over a sustained period (rate is in tons per acre per year). Receiving Waters and Hydrology: Storm -water runoff from construction activities will potentially flow south- southwest towards Tom Creek, a tributary to Clear Creek, Segment 14b of the Lower Colorado Sub -basin and Basin (Regulation 37, Standards for the Lower Colorado River Basin). Clear Creek is a tributary of Roan Creek, which ultimately flows to the Colorado River. The saturated zone in portions of the area is about 54 inches depth to water, primarily due to the close proximity to Torn Creek and Clear Creek. Existing Vegetation: Site is currently vegetated with grasslands used for cattle grazing. Western Wheatgrass (Pascopyrum smithii), Basin Wildrye (Leymus cinereus), and Basin Big Sagebrush (Artemisia tridentate) are common in this area, which is bordered on the north, east and south by riparian woodlands. Dominant observed trees in the area were Boxelders (Acer negundo L.), and the introduced and naturalized New Mexico Locust (Robinia neomexicana). Observed noxious weeds in the area include Bull Thistle (Cirsium vulgare), Common Mullein (Verbascum thapsus), Downy Brome or Cheatgrass (Bromus techtorum), Musk Thistle (Carduus nuntans), Houndstongue (Cynoglossum officinale), and Tamarisk (Tamarix ramosissima). Tamarisk sp. is primarily confined to the Clear Creek channel. Weed control will be part of the ongoing site reclamation plan. Description of Construction Activity: Initial construction activities at the CPF site will involve grubbing, removal and stockpiling of topsoil, followed by cut and fill operations necessary to construct the facility and temporary storage pads. Details of the pad construction can be found on drawing PBSR-59836AVF- CIV-LAY-URS-00000-00001-00 Rev 1. Prior to any earth moving, erosion control BMPs will be installed to minimize site erosion and sedimentation. Additional construction activities will include the replacement and improvement of a culvert under Clear Creek road. A box culvert will be used to replace the existing, undersized corrugated metal pipe culvert. The new culvert is designed to prevent a 100 -year flood event from affecting the CPF site. Erosion and sediment controls including grouted riprap, non -woven control fabric, and check dams will be used for temporary and permanent controls. A berm also will be constructed along the southern edge of the site as part of the site 100 -year flood control. The berm will be protected with a combination of non -woven control fabric and riprap. BMPs will be installed and maintained throughout the initial, interim, and final grading stages. Initial and interim grading activities will include the construction of the facility and temporary storage pads, followed by the culvert replacement. Non -emission source building / enclosure foundations will be excavated at this tim Emission source building / enclosure foundations will be excavation upon receipt of the site air permit. Final grading will be completed after the completion of the building installations to adequately address site drainage issues. A variety of buildings and equipment will be required to support site operations (see Figure 2). The interior of the site will include graveled roads / parking areas and re -vegetated areas. To support site construction, up to six 14 feet by 60 feet and one 75 feet by 75 feet construction trailers plus a TBD number of modular storage units will be placed on the Temporary Storage Area pad. Upon completion of facility, final stormwater controls will be installed and maintained throughout the life of the project. Soil Management: Topsoil is an extremely valuable resource necessary for re -vegetation activities that are mandated by several regulatory agencies (CDPHE, COGCC, Garfield County). Because topsoil formation is a very slow process [ranges from <0.25 mm per year for cold, dry climates (similar to Colorado) to >1.5 mm per year in humid, warm climates], every effort shall be made to conserve existing topsoil by careful excavation and placement in a dedicated topsoil stockpile located east of the primary facility (see Drawing PBSR-59836- AVF-C IV -LAY -U RS -00000-00001 -00). Additional information concerning soil management is provided it URS / Chevron Specification for Site Preparation Stabilization, Soil Management, Earthwork, and Backfill. Potential Sources of Storm -Water Pollution: • Sediment from disturbed areas and/or construction stockpile • Oil products associated with construction vehicles (e.g., refueling operations, engine oil leaks, etc.) • Vehicle washing for weed control • Trash and sanitary facilities Possible storm -water impacts related to these sources are summarized on the following page. Proposed Construction Sequence: (7/2008 thru — 3/2009) • Stake site and clear vegetation • Remove and stockpile topsoil • Install initial storm -water controls (including stockpile) • Install and replace culvert under Clear Creek road with appropriate erosion controls • Grading: general excavation and fill, berm floodplain construction, soil compaction, grading of access and interior roads • Construction of floodplain control berm • Excavation of building / enclosure foundations • Installation of building / enclosure foundations • Construct / install buildings • Final grading of all site features • Stabilization / re -vegetation of interior non -road areas • Install permanent storm -water controls • Erect fencing Site -Specific Storm -Water / Soil Management Plan Page 3/5 Site Name: Central Production Facility/Temporary Storage Area Date of Plan: June 26, 2008, Rev. 1 2. Site Map and Erosion Control — see Figure 1 / Drawing PBSR-59836AVF-CIV-LAY-URS-00000-00001-00 Information included on Erosion Control Plan Drawing: • Construction site boundary • Soil disturbance areas • Storage areas • Surface waters including 100 -yr floodplain limits • Existing and new access roads • Excavation / construction details • Locations of construction & permanent erosion controls (BMPs) 3. Storm -Water Management Controls — NOTE: ALL BMPs ARE SUBJECT TO MODIFICATION AS REOUIRED BY SITE - CONDITIONS. SITE SPECIFIC SWMP AND ASSOCIATED EROSION CONTROL DRAWING(S) WILL BE MODIFIED TO REFLECT FIELD CONFIGURATION AS SOON AS MODIFICATION IS COMPLETED. BMP INSTALLATION NARRATIVE PROVIDED AS BMP GUIDE ATTACHMENT TO THE MASTER PLAN. BMP's SHOWN ON DRAWINGS PBSR-59836-AVF-CIV-LAY-URS-00000-00001-00 AND 025-12-11-065-001. Source Occurrence Potential Storm Water Impact Distance to Surface Water Potential Runoff Concentration BMPs (1) Sediment transport from construction activities Precipitation events / wind events High (w/o BMPs) Low (with well maintained BMPs) = 20 to 1,000+ feet High (without BMPs) — Low (with BMPs) • Straw wattles • Straw bales • Erosion control blankets • Silt fencing, as needed • Check dams • Riprap Oil products associated with condensate transport and construction vehicles (2) Dependent on vehicle maintenance Dependent on fluid source (e.g., high for vehicle refueling; low for minor crankcase leakage) 7,--20 to 1,000+ feet Dependent of• fluid source — majority typically contained in soils • Inspect site for possible leakage Provide designated overnight parking area for construction vehicles — check daily for leakage • Scheduled vehicle maintenance Vehicle washing for weed control (not required after Nov. 15th) (3) Limited to when construction vehicles leave the area Low — water and sediment from this process contained by lined basin 1,000+ feet Low — limited quantities / controlled by lined basin Plastic lined basin with straw wattle berm or equivalent Trash and sanitary facilities (biocide and domestic wastewater) Primarily associated with wind events or sanitary facilities servicing activities Low if inspection process properly implemented = 20 to 1,000+ feet Low —limited fluid volume typically associated with sanitary facilities • Bear -proof trash receptacle with weekly pickup (minimum) or restrict food consumption to separate location (e.g., temporary office) • Keep site clear of general construction trash — verify during weekly inspections Sanitary facilities - Stake -down to prevent tipping during wind events / instruct vendor to minimize spills & leaks during servicing / service frequently () See table on Erosion Control Details on Drawing 003-12-11-061-001. (2) Controls and response actions covered in site Spi I Prevention, Control, and Countermeasures (SPCC) Plan. (3) Per Garfield County guidance (October 26, 2007 meeting with Steve Anthony, Garfield County Vegetation Manager). Site -Specific Storm -Water / Soil Management Plan Page 4/5 Site Name: Central Production Facility/Temporary Storage Area Date of Plan: June 26, 2008, Rev. 1 4. Operational Stabilization / Reclamation Operational Stabilization: Once construction is completed, exterior berms and other disturbed areas will be re -vegetated with the Seed Mix for Sites below 7,000 ft, using application rates and plant species designated in the URS / Chevron Specification for the Re -Vegetation of Disturbed Areas, document number: PBSR-ALL-CIV- SPC-URS-00000-00004-00. Any adjacent areas disturbed by construction traffic will be re -vegetated at this time. Final stabilization will be complete when areas have returned to 70 -percent of the original vegetation cover. The gravel access roads (installed per construction drawings / specifications) will provide final stabilization in these areas but will be monitored to determine if maintenance operations are required. Noxious weed control will be continued on an as needed basis. Reclamation: The site will be reclaimed after the end of its operational life in accordance with Garfield County land use requirements. Reclamation activities will include: removing pipelines, gravel from roads and access pads; re -grading the site to the original contours (approximate); replacing topsoil; revegetation with appropriate seed mix; and installing and maintaining any required storm -water controls until final stabilization is achieved. Site inspections will be conducted in accordance with the Master SWMP (documented by Master Inspection Form). 5. Inspection / Maintenance Site-specific areas requiring inspection: • Site perimeter and nearby areas (e.g., adjacent stream channel — for possible trash) • Disturbed / re -vegetated areas • Soil stockpiles • Vehicle wash area • Trash container / sanitary facilities • BMPs Site -Specific Storm -Water / Soil Management Plan Page 5/5 Site Name: Central Production Facility/Temporary Storage Area Date of Plan: June 26, 2008, Rev. 1 6. Site Specific SWMP Revisions Description of revision Initiated/approved by: Date Note: Insert additional sheets as needed. 7. Site -Specific SWMP Administrator (only required if different from Site Administrator) Signature: Title: Printed Name: Date: PRIVATE PAD IC 55 RAP 20' AWE LEAF G&1 11 1.616.039.21 E 2.198 311.T2 N 1. .911.55 11 1.615.011.1 E 2.95$.161.9T E 2.19142 PAD &CUSS 20' DOSE LDS GTE N 1.615.111.05 E 2.191.951 ,20 PC ACCESS we 20' DOME LEA GATE N 1,645.632.19 [ 2 191.119.22 Pia ACCESS 20' DOUBLE LEAF CATE N 1.645.899.52 E 2.191.110.05 N 1.645.622.13 E 2.191.326.30 11 1.11 .615.16 E 2.1 .146.82 11 1.645.126.20 E 2.191.459 1. MNIGATE N 1.645.601.26 E 2.191.291.11 Ilk/11111101 II SAIf AI1 911111 40h L 11 1619 12!01 �� �� , 9119190955 -, ���� At AN 1 fti \`„��11�a�,J'/`1�rt�J�� 1 PAD ACCESS RAP 20MOLE LEA N 1.615.436.22 F 2 191.903.65 N 1.615.511.12 E 2.191.217.19 ISSUED FOR APPROVAL ISSUED FOR CENSTRUCT ON ISSUED FOR CONSTRUCT ON - ADDED RIPRAP TO CPF BERm 101001. PROJECT NO.: 29151 DRAM: CR CNEOIEO: 111 5 IAl 11990960 FOR CONSTRUCTION MASS SIDLED 6 DATED. DESTROY ALS PRINTS BEARING EARLIER DATE NM REV.IC. SCALE: DATE: 0T-11-07 DATE: 01-11-08 AS 511004 URS IMS 1. REFERENCE PARINGS: PSAI-59I3MW -0 I Y-0IL'.RS-E0M0-00001-00 F09 ER05101 801180. DETAILS PCSA-5983614F-CI V -0A1 -IBS -0D000 -0p002-00 FON FINISH GRADING PLAN 1. DELA 0A6 A5 REOIIRFO F09 DRAINAGE CENTRO - 3. FEET EROSIOI 801110, M THE SIDE 59.09E EC ME CPI SORB BEM. INSTALL IA5 DOM 114E '99.' RIPRIP. 92 WOES 111161 OVER NM-RIEN FILLER FAMIC. V/////A DOA( WAITED STRAW AO 56EOED FLOM RAIN 8031011? GROUTED RIP8P 11. DEEP OVER 1101-110VEN FILTER FABRIC. I5EE IDT( 31 -11--11- NEN 6' CHAIN LINE FENCE STRAW WATTLES FIR PICANCE BASIN M10UL DAS DIVED:PIENT PRORAN TBI DATER MN*DEIENT RAN ORAINACE FLOW DI9CCTIM SCALE: I INCE = 50 PEE1 50' 0 50' Ch_ Evron 400 MidContlnent / Alaska SBU Chevron North America IWOExploration and Production Washington Division 10550 Rldwand Ave. - Ewston. T% 11012 12811 529-3100 PICEANCE BASIN DEVELOPMENT CENTRAL PRODUCTION FACILITY PAD EROSION CONTROL PLAN DWG. 110. PBSR-59836AVF-CIV-LAY-URS-00000-00001-00 REV 1 2 W"N613 wMnjP N.11.EFID1618- 1 - MEP D C 4— B A 100 -S90 -11 -Z1 -S20 O BLRY IPS/Cit EIO DF BLY[EI IN A TRENCH 6' DEEP BY V 110E. KOREY FABRIC ARMED IN TRENCH O USE A 6' FERN NEREVER 0E RRL O BLANKET E105 MO ANOTHER BEGINS. O USE A A' OWERAP !DREYER 150 WIDENS D BLOEET RRC APPLIED 510E 81 SIDE. STARE PATTERN: 11111160 rC 3 PER SWORE MO. A ALO 611[8 SLOTS WOAD BL MADE EVERY 11'. INSERT A FOLD OF THE BLAME! 1010 A TRENCH 6' SIDE BY 6' (EP 00 TAV Flinty. LAY THE &08(T SNOBBY 01 TIE SPEW 6 TIE SOIL: CODE 5181104 THE BLAIEEI. AND PO 101 ARON EIIILLE5. INSTALL STAPLE 2D' 01 CENTER IN TRENCH. PLACE EtuaET PARALLEL 10 THE DIRECTION CF FLOW. 00101 JOIN STRIPS IN TIE CENTER R THE 01101. USE OIE[A SLOTS AS REWIRED. IEIEI SCE SKCIFICA1106 01 PLANS FOR :OE DETAIL RACE CNEEI PARALLEL TO 11E DIRECTION 0 FLOW NO ANLN01 SECURELY. BRING BLAIEE7 TO A LEVEL AREA DOTE TERNINATING THE II6r41A11OI. REM OISCIPLI4 ARCH. CIVIL ELECTRICAL ENVIRON. GEN. MR0IG. ON BY APPROVAL DATE EROSION CONTROL BLANKET REC010 015CIR11E 40404 :CAL I CLCAR PIPING PROCESS DA / OC RE BY NTS YA DATE t DATE ADJACENT ROLLS LULL TIDRITIT WW1 '1� 0" 01A STRAW DLL W // `1" R is R 2'-6' STAKE \ \ W1 5146 ROLLS MST BE BARD ALCM UDE *HOURS SEDIMENT. 0100116 MATTER. MD NATIVE SEEDS ARE CMIIPCD BOUND THE ROLLS I' A 1" Y V -E STARE 11V9.1 10' DIA STRAW RRL ITTP.I SPACING ((PEWS 01 SOIL TYPE MO UUWE STCEPtSS 1' 0 l' ! 2'4' SILLS 10" DIA STRAN 6Rl 0 STRAW 60.1 INSTALLATION REWIRES THE PLARLENI R BE ALOUD TOALIRI04 6006 OR LAW* RRL. W5/ OI STRAW WATTLE ROLL TYPICAL DETAIL NTS II' it 15' • 56' TYPICAL ER051a BALES o p o 0 o 0 0 0 0 0 PLAN SECTION A -A SILT (ABM P051LSED 10 SILT FENCE FABRIC ARMED IN TRENCH APO ATTACHED FIR.Y TO POST oft E0051d BALE L • DISTANCE SUCH THAT POINTS C AHD 0 ARE 0' EWAL ELEYATIa III -111141= III 6' YIN. =111=f �f— —Ill -1 I l l l 111-111—III—I I III-111=117±- 11[111—H(-11._.=. L—III I III =111 11=III=111- 111 ,. RENSM AEnelurz0 —1 1-c_111=111—WF: ==-111--111— • 5(01418716EN IT 1EA0Es hil ' DIE HALF O' OPINED 0111416141 POINT 0 ER05101 BALE POINTS A 1661 BE RIDER DWI POINT B 10' CHANNEL CONTROL BALES NTS PDS: 12' R E'101111/1.1 24' XIX. 6 t 6'186NCH 24' CHANNEL PROFILE SILT FENCE FABRIC 0401) IN TREND NNB�RET AIIACIED 6' • 6'IRN01 42' LN TYPICAL SILT FENCE CONSTRUCTION NIS REVISION BY CDR DRAWING STAINS 12-21-01 15511E0 FON APPROVAL I551ED REV DUE 5D6 PEN PBELU:DIARY A STRUCTURAL APPROLEO FOR (0151RUCl1OJ 8 7 101 APPROVED (CM CONSTANC71011 LM.E55 SIDED I. DATED. DESTROY ALL PRINTS DEMING EARLIER DATE 1/01 REV./47 PROJECT NO.: DRAWN: GR 01(01(0: w DATE: 08-10-0T DATE: Chemin MidC ontinen t/Alosko SBLJ porChevron North Americo E E fe plotion and Production PRELIMINARY NOT FOR CONSTRUCTION AREA: 025 FIELD: C0: GARFIELD 57: CO. PROPERTY 5x10061 PROPERTY COACH: SCALE: A5 SHOWN ® Washington Group International 1600 E. Union Ave. - Denver. CO 80251 - 5051 843-2000 PICEANCE BASIN DEVELOPMENT CENTRAL PRODUCTION FACILITY PAD EROSION CONTROL DETAILS 05G x0' 025-12-11-065-001 REY A 6 4 3 1101051510X3 RE.PAIH.M0.N11X 101(851010 01011PmLDA16JX0.I I1XS 2 1 200f1-017-065-00: DULP C B A URS Washington Division PICEANCE BASIN NATURAL GAS DEVELOPMENT PROGRAM Chevron ONO GARFIELD COUNTY, COLORADO SPECIFICATION FOR EROSION AND SEDIMENT CONTROL 1 Revised to include additional relevant BMPs EB SMC 7-2-08 0 Approved for Construction A Prelim. Issued for Review/Comments MN JRV 8-10-07 REV. DESCRIPTION BY CI-IKD APVD RVWD DATE REVISIONS CLIENT: CHEVRON North America Exploration and Production PROJECT: Piceance Basin Natural Gas Development Program JOB NO.: 29454 DOC. NO.: PBSR-ALLCIV-SPC-URS-00000-00003-00 H:\_Projects\Chevron\29021 CNAEP\SPECIFICATIONS\CivillEB AC 12A003_Erosion and Sediment Control.doc Washington Division Chevron ItiO Date: 4/29/08 EROSION & SEDIMENT CONTROL PICEANCE BASIN NATURAL GAS DEVELOPMENT PROGRAM Doc. No. PBSR-ALLCIV-SPC-URS- 00000-00003-00 Rev: 0 Page: 2 of 17 TABLE OF CONTENTS SECTION PAGE 1. GENERAL 4 1.1 Scope 4 1.2 Work Included 4 1.3 Related Sections 4 1.4 Definitions 4 1.5 References and Standards 4 1.6 Documents 5 1.7 Submittals 5 2. PRODUCTS AND BEST MANAGEMENT PRACTICES (BMP) 5 2.1 Stabilized Construction Entrance/Exit 5 2.2 Land Grading 5 2.3 Gravel Surfacing 5 2.4 Surface Roughening 6 2.5 Protective Bales 6 2.6 Erosion Control Blankets 6 2.7 Earth Dikes 6 2.8 Silt Fences 6 2.9 Riprap 7 2.10 Riprap — Other 7 2.11 Erosion/Sediment Control Logs/Wattles 7 2.12 Vegetative and Grass Buffers 7 2.13 Check Danis 8 2.14 Culverts 8 2.15 Culvert Inlet and Outlet Protection 9 Washington Division Chevron IMO Date: 4/29/08 EROSION & SEDIMENT CONTROL PICEANCE BASIN NATURAL GAS DEVELOPMENT PROGRAM Doc. No. PBSR-ALLCIV-SPC-URS- 00000-00003-00 Rev: 0 Page: 3 of 17 2.16 Concrete Washout Facilities 9 2.17 Sanitary/Septic (Port -O -Let) Waste Management 9 3. EXECUTION 9 3.1 Stabilized Construction Entrance/Exit 9 3.2 Land Grading 10 3.3 Gravel Surfacing 11 3.4 Surface Roughening 11 3.5 Protective Bales 12 3.6 Erosion Control Blankets 12 3.7 Earth Dikes 14 3.8 Silt Fences 14 3.9 Riprap 14 3.10 Erosion/Sediment Control Logs/Wattles 15 3.11 Vegetative and Grass Buffers 15 3.12 Check Dams 15 3.13 Culverts 15 3.14 Culvert Inlet and Outlet Protection 15 3.15 Concrete Washout Facilities 16 3.16 Sanitary/Septic (Port -O -Let) Waste Management 16 Chevron Washington Division Date: 4/29/08 EROSION & SEDIMENT CONTROL PICEANCE BASIN NATURAL GAS DEVELOPMENT PROGRAM Doc. No. PBSR-ALLCIV-SPC-URS- 00000-00003-00 Rev: 0 Page: 4 of 17 1. GENERAL 1.1 Scope This Specification covers the product and construction requirements for the Erosion and Sediment Control work for Chevron's Piceance Basin Natural Gas Development Program. Construction operations will be carried out in such a manner that erosion will be controlled and water and air pollution minimized. State and local laws concerning pollution abatement shall be followed. This includes complying with and implementing the Storm -Water Pollution Prevention Plan required by the Construction Storm -Water Permit. Construction plans shall detail erosion and sediment control measures to be employed during the construction process. 1.2 Work Included The overall work included consists of the following: planning construction activities, the installation of erosion control devices, top soil placement, seeding, mulching, and establishing erosion control practices during construction activities on the site. More specific work includes, but is not limited to the following: furnishing and installation of straw bale dikes; earth dikes; silt fences; stabilized construction entrances, temporary and permanent seeding to include top soil placement and mulching including furnishing and placing of erosion control and re -vegetation matting. 1.3 Related Sections 1.3.1 Specification No. 12-0-002 - Site Preparation / Stabilization, Soil Management, Earthwork, and Backfill 1.3.2 Specification No. 12-0-004 - Seeding, Hydro -Mulching and Re -vegetation 1.4 Definitions 1.4.1 Owner: Chevron North America Exploration and Production 1.4.2 Engineer: URS Corporation Washington Division 1.4.3 Contractor: TBD 1.4.4 Subcontractor: Firm undertaking the scope of work as defined in this Specification 1.4.5 State: Refers to State of Colorado 1.5 References and Standards The codes, standards and regulations of the following organizations in effect August 10`h, 2007 form a part of this Specification to the extent indicated by the references thereto: 1.5.1 American Society for Testing and Materials (ASTM). 1.5.2 Colorado Department of Transportation (CDOT), Standard Specifications for Road and Bridge Construction. Washington Division Chevron 11100 Date: 4/29/08 EROSION & SEDIMENT CONTROL PICEANCE BASIN NATURAL GAS DEVELOPMENT PROGRAM Doc. No. PBSR-ALLCIV-SPC-URS- 00000-00003-00 Rev: 0 Page: 5 of 17 1.5.3 Bureau of Land Management (BLM) — Oil and Gas, Surface Operating Standards for Oil and Gas Exploration and Development. Fourth Edition. Should a conflict be found to exist between any applicable portion of the referenced codes and standards and this Specification, the conflict shall be submitted to the Engineer for resolution before proceeding with the affected work. 1.6 Documents Typical Best Management Practices (BMPs) Details, URS Document Number: PBSR-ALL-RGL- PMT-URS-00000-00003-00. Chevron Piceance Basin Natural Gas Development Program, Storm -Water Management Plan, Construction Storm -Water Field Permit, URS Document Number: PBSR-ALL-RGL-PMT-URS- 00000-00002-00 and PBSR-ALL-RGL-PMT-URS-00000-00002-00. Rust Constructors, Chevron Piceance Project, Project Safety Plan, Fugitive Dust Control Plan, Rev. 1, Procedure Number: REC-06. 1.7 Submittals Prior to construction, submit a plan for approval to the Engineer or their designated representative, showing implementation of the temporary and permanent erosion and sediment control measures as shown on the Drawings. 2. PRODUCTS AND BEST MANAGEMENT PRACTICES (BMP) 2.1 Stabilized Construction Entrance/Exit 2.1.1 A temporary stabilized vehicular entrance/exit should be established at all points where traffic will enter and exit the site. A stabilized construction entrance/exit reduces or eliminates the tracking of sediment onto public right-of-way, streets, or parking areas where it can be washed into local streams or become airborne pollution due to wind affects. 2.2 Land Grading 2.2.1 Land grading involves reshaping the ground surface to planned grades as determined by an engineering survey, evaluation, and layout. Land grading provides more suitable topography for buildings, facilities, and other land uses and helps to control surface runoff, soil erosion, and sedimentation during and after construction. 2.3 Gravel Surfacing 2.3.1 Gravel surfacing simply involves covering exposed earth surfaces with gravel to prevent soil erosion from occurring. 2.3.2 Gravel surfacing should be used on any exposed earthen areas, including roadways; parking areas; laydown, staging, and storage areas; and around foundations of structures, including where roof drains discharge. Chevron /11401/ Washington Division Date: 4/29/08 EROSION & SEDIMENT CONTROL PICEANCE BASIN NATURAL GAS DEVELOPMENT PROGRAM Doe. No. PBSR-ALLCIV-SPC-URS- 00000-00003-00 Rev: 0 Page: 6 of 17 2.4 Surface Roughening 2.4.1 Surface roughening is a temporary erosion control practice whereby the soil surface is roughened by the creation of grooves, depressions, or steps that run parallel to the contour of the land. 2.4.2 Surface roughening is appropriate for all slopes and should be performed immediately after rough grades have been established in an area. 2.4.3 Surface roughening can also be used to help establish vegetative cover by reducing runoff velocity and giving seed an opportunity to take hold and grow. 2.4.4 Surface roughening can be used in combination with other erosion control measures such as mulching and seeding. 2.5 Protective Bales 2.5.1 Protective straw bales or other material determined to be acceptable by the Engineer or its designated representative containing approximately five (5) cubic feet of material, and weighing not less than 35 pounds. 2.5.2 Bales shall be twine -tied. A. Bales shall be certified free of noxious weeds. 2.6 Erosion Control Blankets 2.6.1 Temporary erosion control blankets such as SC150 by North American Green or approved equal. 2.6.2 Permanent erosion control blankets such as SC250 by North American Green or approved equal. 2.7 Earth Dikes All materials used as embankment for earth dikes shall be suitable for the intended use and classified as common fill which meets the requirements of the Geotechnical Investigation Report and related "Site Preparation and Earthwork" Specification. 2.7.1 The Engineer or its designated representative will approve material from Project site excavations. 2.7.2 The Engineer or its designated representative will approve off-site materials. 2.8 Silt Fences 2.8.1 Because of the high winds and severe weather in the Piceance Basin, silt fencing shall only be used when needed for temporary control or for small, sheltered areas. Chevron Washington Division Date: 4/29/08 EROSION & SEDIMENT CONTROL PICEANCE BASIN NATURAL GAS DEVELOPMENT PROGRAM Doc. No. PBSR-ALLCIV-SPC-URS- 00000-00003-00 Rev: 0 Page: 7 of 17 2.8.2 Silt Fence Fabric: The fabric shall meet the following specifications unless otherwise approved. Fabric Properties Minimum Acceptance Value Test Method Grab Tensile Strength (lbs) 90 ASTM D 1682 Elongation at Failure (%) 50 ASTM D 1682 Mullen Burst Strength (PSI) 190 ASTM D 3786 Puncture Strength (lbs) 40 ASTM D 751 (modified) Slurry Flow Rate (qal/min/s.f.) 0.3 Virginia DOT VTM-51 Equivalent Opening Size 40-80 US Std Sieve CW -02215 Ultraviolet Radiation Stability (%) 90 ASTM G-26 2.8.3 Fence Posts (for fabricated units): The length shall be a minimum of 36 inches long. Wood posts will be of sound quality hardwood with a minimum cross sectional area of three (3) square inches. Steel posts will be standard T and U section weighing not less than one (1) pound per linear foot. 2.8.4 Prefabricated Units: "Sedimentstop" by North American Green or approved equal may be used in lieu of the above method providing the unit is installed per manufacturer's instructions. 2.9 Riprap 2.9.1 Material shall be durable, angular field or quarry stones of approved quality, sound hard free from seams and other structural defects. 2.9.2 Material shall be resistant to weathering and water actions and conform to the following requirement. A. Specific Gravity AASHTO T85 2.5 min. B. Absorption AASHTO T85 4% max C. Course durability index AASHTO T210 52 min. 2.10 Riprap — Other 2.10.1 Permanent reinforcement mat such as VMAX P550 by North American Green or approved equal could be used in place of riprap. 2.11 Erosion/Sediment Control Logs/Wattles 2.11.1 An erosion/sediment control log/wattle consists of a wattle with an excelsior, straw, compost, or coconut fill material constructed to create a pervious filter, able to facilitate overtopping. The log/wattle promotes sediment removal on the upgradient side and a reduction in flow velocities. 2.12 Vegetative and Grass Buffers 2.12.1 Vegetative and grass buffers are used to maintain vegetated areas that are down gradient of earthwork activities. Creating or leaving existing green belts intact can slow sheet flows, act as a natural sediment barrier and protect the site perimeter. Chevron Washington Division Date: 4/29/08 EROSION & SEDIMENT CONTROL PICEANCE BASIN NATURAL GAS DEVELOPMENT PROGRAM Doc. No. PBSR-ALLCIV-SPC-URS- 00000-00003-00 Rev: 0 Page: 8 of 17 2.12.2 Vegetative and grass buffers should be incorporated into site drainage, street drainage, and master drainage planning. 2.12.3 Because their effectiveness depends on having an evenly distributed sheet flow over their surface, the size of the contributing area, and the associated volume of runoff have to be limited. 2.12.4 Flow can be directly accepted from an impervious area such as from parking lots and building roofs, provided the flow is distributed uniformly over the' strip. 2.12.5 Vegetative and grass buffers should be protected from excessive pedestrian or vehicular traffic that can damage the grass cover and affect even sheet -flow distribution. 2.13 Check Dams 2.13.1 Check dams are small, temporary or permanent dams constructed across a drainage ditch, swale or channel to reduce the velocity of concentrated flows and to trap sediment eroded from upstream. Check dams can be constructed out of rocks, gravel -filled sandbags or straw bales. 2.13.2 Check dams can be used in open channels that receive flow from drainage between 1 and 10 acres, in steeply sloped swales, and in swales that need protection during the establishment of grasses or prior to installation of a non -erodible lining. 2.13.3 Check dams can be constructed of rock, logs, sandbags, or straw bales: A. When using rock or stone, the material diameter should be 2 to 15 inches. B. Logs should have a diameter of 6 to 8 inches. 2.13.4 All check dams should have a maximum height of 3 feet. 2.13.5 The center of the dam should be at least 6 inches lower than the edges to create a weir effect that helps to channel flows away from the banks and prevent erosion. 2.13.6 Additional stability can be achieved by implanting the dam material approximately 6 inches into the sides and bottom of the channel 2.13.7 When installing more than one check dam in a channel, outlet stabilization measures, such as riprap, should be installed below the final dam in the series. 2.14 Culverts 2.14.1 Culverts consist of concrete or metal pipe or structures (box culverts) that are installed to conduct intermittent or constant flow around obstacles or under roadways or other related infrastructure (utilities such as pipelines, electrical lines, water, sewer, etc.). 2.14.2 Culverts can be used to conduct flow around obstacles or under roadways or other related infrastructure and to handle intermittent or constant, manmade or natural flows. 2.14.3 When installing culverts, confirm that all related stream permitting is obtained prior to installing temporary stream crossings and that all work will be in compliance with such permitting — including USAGE CWA Section 401/404 permitting requirements. Chevron Washington Division Date: 4/29/08 EROSION & SEDIMENT CONTROL PICEANCE BASIN NATURAL GAS DEVELOPMENT PROGRAM Doc. No. PBSR-ALLCIV-SPC-URS- 00000-00003-00 Rev: o Page: g of 17 2.15 Culvert Inlet and Outlet Protection 2.15.1 Culvert inlet and outlet protection includes BMPs installed to prevent erosion, scour, and undercutting at culvert inlet and outlets. 2.15.2 Culvert inlet and outlet protection typically consists of other BMPs installed in conjunction with typical culverts, in particular riprap. 2.15.3 When installing culverts inlet and outlet protection, confirm that all related stream permitting is obtained prior to installing temporary stream crossings and that all work will be in compliance with such permitting — including USACE CWA Section 401/404 permitting requirements. 2.16 Concrete Washout Facilities 2.16.1 Concrete washout facilities are used to prevent or reduce the discharge of pollutants to storm - water from concrete waste by conducting washout offsite, performing onsite washout in a designated area, and training employee and subcontractors. 2.16.2 Concrete washout facilities are used on construction projects where: A. Concrete is used as a construction material or where concrete dust and debris result form demolition activities. B. Slurries containing portland cement concrete or asphalt concrete are generated, such as from saw cutting, coring, grinding, grooving, and hydro -concrete demolition. C. Concrete trucks and other concrete -coated equipment are washed onsite. D. Mortar -mixing stations exist. 2.17 Sanitary/Septic (Port -O -Let) Waste Management 2.17.1 Proper sanitary and septic waste management prevents the discharge of pollutants to storm - water from sanitary and septic waste by providing convenient, well-maintained facilities, and arranging for regular service and disposal. 2.17.2 Sanitary or septic wastes should be treated or disposed of in accordance with state and local requirements. In many cases, one contract with a local facility supplier will be all that it takes to make sure sanitary wastes are properly disposed. 3. EXECUTION Contractor shall assume sole responsibility for temporary and permanent erosion and sediment control, as shown on the Drawings. Damages from erosion and sedimentation shall be corrected at no cost to the Engineer. 3.1 Stabilized Construction Entrance/Exit 3.1.1 Construct stabilized construction entrance/exits at the beginning of earthwork operations at the locations shown on the Drawings. 3.1.2 Entrance/exits must be properly graded to prevent runoff from leaving the site. Chevron 1111011 Washington Division Date: 4/29/08 EROSION & SEDIMENT CONTROL PICEANCE BASIN NATURAL GAS DEVELOPMENT PROGRAM Doc. No. PBSR-ALLCIV-SPC-URS- 00000-00003-00 Rev: 0 Page: toot 17 3.1.3 Entrance/exits should be designed to support the heaviest vehicles and equipment that will use it. 3.1.4 Aggregate Thickness - Not less than ten (10) inches for all entrances. 3.1.5 Width - 20 foot minimum but not less than the full width of points where ingress or egress occurs. 3.1.6 Length - As required, but not less than 50 feet. 3.1.7 Aggregate material should be placed over the geotextile fabric to prevent sediment from the base material from migrating into the aggregate. 3.1.8 Piping of surface water under entrance shall be provided as required. If piping is not feasible, a mountable berm with five horizontal to one vertical (5:1) slopes will be permitted. 3.1.9 The entrance shall be maintained through the duration of this Contract in a condition which will prevent tracking of sediment onto public rights-of-way or streets. This may require periodic top dressing with additional aggregate. 3.1.10 All sediment spilled, dropped, or washed onto public rights-of-way must be removed immediately. 3.1.11 The gravel and filter fabric must be removed upon completion of the construction and disturbed soil areas resulting from removal shall be permanently stabilized. 3.1.12 When necessary, wheels must be cleaned to remove sediment prior to entrance onto public rights-of-way. A. When washing is required, it shall be done on an area stabilized with aggregate which drains into an approved sediment trapping device. B. All sediment shall be prevented from entering storm drains, ditches, or watercourses. 3.2 Land Grading 3.2.1 Grading activities should maintain existing drainage patterns as much as possible. 3.2.2 Before grading activities begin, decisions must be made regarding the steepness of cut -and -fill slopes and how the slopes will be protected from runoff, stabilized, and maintained. 3.2.3 A grading plan should be prepared that establishes and includes: A. Identification of areas of the site to be graded. B. How drainage patterns will be directed. C. How runoff velocities will affect receiving waters. D. Information regarding when earthwork will start and stop. E. The degree and length of finished slopes. F. Where and how excess material will be disposed of (or where borrow materials will be obtained if needed). Washington Division Chevron 1110 IRO Date: 4/29/08 EROSION & SEDIMENT CONTROL PICEANCE BASIN NATURAL GAS DEVELOPMENT PROGRAM Doc. No. PBSR-ALLCIV-SPC-URS- 00000-00003-00 Rev: 0 page: 11 of 17 G. Berms, diversions, and other storm -water BMPs that require excavation and filling should be incorporated into the grading plan. 3.3 Gravel Surfacing 3.3.1 Engineering design is required for gravel to be used on roadways, parking areas, and around foundations, including proper crowning features and to meet appropriate compaction requirements. 3.3.2 Selection of gravel size and depth should consider the use of the area to be covered, including factors such as types and frequency of traffic, duration of establishment (temporary or permanent), anticipated storm -water volumes (due to direct precipitation and surrounding area runon/runoff), etc. 3.3.3 Permeable fabric membranes/liners should be installed at the soil and gravel interface to prevent rutting and soil and mud from rising through the gravel due to traffic impacts. 3.3.4 Binders such as magnesium chloride may be applied to help fix and secure gravel surfaces in place. 3.3.5 The condition of gravel surfaces should be inspected regularly, after any major storms and at least once a year to ensure that the surfaces and subsurfaces are sound and have not been subject to erosion. 3.3.6 Gravel should be replenished due to losses from compaction, drag -out, and spreading, especially in high -traffic areas. 3.3.7 Gravel may need to be replaced and/or repaired if soil or mud rises through or is tracked by traffic into gravel areas and following winter seasons, especially if surfaces are plowed for snow removal. 3.4 Surface Roughening 3.4.1 Cut Slope Roughening: A. Stair -step grade or groove the cut slopes that are steeper than 3:1. B. Use stair -step grading on any erodible material soft enough to be ripped with a bulldozer. Slopes consisting of soft rock with some subsoil are particularly suited to stair -step grading. C. Make the vertical cut distance less than the horizontal distance, and slightly slope the horizontal position of the "step" in toward the vertical wall. D. Groove the slope using machinery to create a series of ridges and depressions that run across the slope, on the contour. 3.4.2 Fill Slope Roughening: A. Place fill slopes with a gradient steeper than 3:1 in lifts not to exceed 8 inches, and make sure each lift is properly compacted. Washington Division Chevron 1111110 Date: 4/29/08 EROSION & SEDIMENT CONTROL PICEANCE BASIN NATURAL GAS DEVELOPMENT PROGRAM Doc. No. PBSR-ALLCIV-SPC-URS- 00000-00003-00 Rev: 0 Page: 12 of 17 B. Ensure that the face of the slope consists of loose, uncompacted fill 4 -6 inches deep. C. Use grooving or tracking to roughen the face of the slopes, if necessary. D. Apply seed, fertilizer and straw mulch then track or punch in the mulch with the bulldozer. E. Do not blade or scrape the final slope face. 3.4.3 Roughening With Tracked Machinery: A. Limit roughening with tracked machinery to soils with a sandy textural component to avoid undue compaction of the soil surface. B. Operate tracked machinery up and down the slope to leave horizontal depressions in the soil. Do not back -blade during the final grading operation. C. Immediately seed and mulch roughened areas to obtain optimum seed germination and growth. D. Check for erosion and sloughing, and make any required repairs. 3.5 Protective Bales 3.5.1 Install sediment barrier bales at the locations as shown on the Drawings. 3.5.2 Straw bale barriers should consist of two parallel rows with: A. The ends of bales butted tightly. B. Butt joints staggered between front and back rows. C. Each row of bales trenched in and firmly staked. 3.5.3 Anchor bales with either two wood stakes or four bars driven through the bale and into the soil. Drive the first stake towards the butt joint with the adjacent bale to force the bales together. 3.5.4 Straw bales degrade, especially when exposed to moisture. Rotting bales will need to be replaced on a regular basis. 3.5.5 Sediment that accumulates in the BMP must be periodically removed in order to maintain BMP effectiveness. Sediment should be removed when the sediment accumulation reaches one-third of the barrier height. 3.5.6 Remove straw bales when no longer needed. Remove sediment accumulation, and clean, regrade, and stabilize the area. 3.6 Erosion Control Blankets 3.6.1 Erosion control blankets/mats should not be used in swales with slopes greater than 5 percent or with storm -water velocities > 8 feet per second. Chevron Washington Division Date: 4/29/08 EROSION & SEDIMENT CONTROL PICEANCE BASIN NATURAL GAS DEVELOPMENT PROGRAM Doc. No. PBSR-ALLCIV-SPC-URS- 00000-00003-00 Rev: 0 Page: 13 of 17 3.6.2 Erosion control blankets/mats should not be used in areas subject to scour from high flows (e.g. stream banks) unless designed by an engineer. 3.6.3 Permits shall be obtained prior to any streambank or shoreline installation of erosion control blankets/mats, including United States Army Corps of Engineers (USACE) Clean Water Act (CWA) Section 401/404 permits. 3.6.4 Proper site preparation is essential to ensure complete contact of the protection matting with the soil: A. Grade and shape area of installation. B. Remove all rocks, clods, vegetative or other obstructions so that the installed blankets, or mats will have direct contact with the soil. C. Prepare seedbed by loosening 2-3 inches (50-75 mm) of topsoil above final grade. D. Seed area before blanket installation for erosion control and re -vegetation. (Seeding after mat installation is often specified for turf reinforcement application.) 3.6.5 U-shaped wire staples, metal geotextile stake pins, or triangular wooden stakes can be used to anchor mats to the ground surface: A. Wire staples should be a minimum of 11 gauge. B. Metal stake pins should be 3/16 inch diameter steel with a 1 1/2 inch steel washer at the head of the pin. C. Wire staples and metal stakes should be driven flush to the soil surface. D. All anchors should be 6-8 inches long and have sufficient ground penetration to resist pullout. E. Longer anchors may be required for loose soils. F. Begin at the top of the slope and anchor its blanket in a 6 inch deep x 6 inch wide trench. G. Backfill trench and tamp earth firmly. H. Unroll blanket downslope in the direction of the water flow. The edges of adjacent parallel rolls must be overlapped 2-3 inches and be stapled every 3 feet. J. When blankets must be spliced, place blankets end over end (shingle style) with 6 inch overlap. Staple through overlapped area, approximately 12 inches apart. K. Lay blankets loosely and maintain direct contact with the soil - do not stretch. L. Blankets shall be stapled sufficiently to anchor blanket and maintain contact with the soil. Chevron Washington Division Date: 4/29/08 EROSION & SEDIMENT CONTROL PICEANCE BASIN NATURAL GAS DEVELOPMENT PROGRAM Doc. No. PBSR-ALLCIV-SPC-URS- 00000-00003-00 Rev: 0 Page: 14 of 17 M. Staples shall be placed down the center and staggered with the staples placed along the edges. N. Steep slopes, 1:1 to 2:1, require 2 staples per square yard. O. Moderate slopes, 2:1 to 3:1, require 1-2 staples per square yard (1 staple 3' on center). P. Gentle slopes require 1 staple per square yard. 3.6.6 Any failure should be repaired immediately. Replacement of fabric sections may also be necessary. 3.6.7 If washout or breakage occurs, re -install the material after repairing the damage to the slope or drainageway. 3.7 Earth Dikes Install earth dikes at the locations shown and as detailed on the Drawings or in accordance with BMP. 3.8 Silt Fences 3.8.1 Install silt fences at the locations shown and as detailed on the Drawings. 3.8.2 All silt fences shall be placed as close to the contour as possible and the area below the fence must be undisturbed or stabilized. 3.8.3 Silt fence and fence stakes and posts should be installed as follows: A. Stakes or posts should be placed to the downhill side of the fence. B. The bottom edge of the fabric must be continuously and securely entrenched and covered with backfill or anchored for its entire length to prevent undermining. 3.8.4 Silt fences must be inspected regularly to make ensure they are intact and that there are no gaps where the fence meets the ground or tears along the length of the fence. 3.8.5 If gaps or tears are found, repair or replace the fabric immediately. 3.8.6 Remove accumulated sediments from the fence base when the sediment reaches one-third to one-half the fence height. 3.8.7 When silt fences are removed the accumulated sediment must be removed as well. 3.9 Riprap 3.9.1 The following inspection and maintenance procedures should be followed: A. Inspect for signs of slope erosion under and around the rock protection. B. Inspect for signs of erosion and undercutting around structures. Chevron 1110 Washington Division Date: 4/29/08 EROSION & SEDIMENT CONTROL PICEANCE BASIN NATURAL GAS DEVELOPMENT PROGRAM Doc. No. PBSR-ALLCIV-SPC-URS- 00000-00003-00 Rev: 0 Page: 15 of 17 C. Check for erosion and displacement of rock at inlets and outlets. D. Inspect for displacement of riprap or damage to underlying fabric, and signs of scour beneath the riprap or around the outlet. E. Replace rock and repair as needed. 3.10 Erosion/Sediment Control Logs/Wattles 3.10.1 Erosion/sediment control logs/wattles should be trenched into the ground a minimum of 2 inches and staked or stapled into the ground. 3.10.2 Sediment accumulated upstream of wattles should be removed when the sediment depth upgradient of the log/wattle is within Y of the height of the crest or when debris accumulation compromises the effectiveness of the feature. 3.11 Vegetative and Grass Buffers 3.11.1 Install vegetative and grass buffers at the locations shown and as detailed on the Drawings. 3.12 Check Dams 3.12.1 Large debris, trash, and leaves should be removed from check dams during routine inspections. 3.12.2 If erosion or heavy flows cause the edges of a dam to fall to a height equal to or below the height of the center, repairs should be made immediately. 3.12.3 Accumulated sediment should be removed from the upstream side of a check dam when the sediment has reached a height of approximately one-half the original height of the dam (measured at the center). 3.12.4 All accumulated sediment should also be removed prior to removing a check dam. 3.12.5 Removal of a check dam should be completed only after the contributing drainage area has been completely stabilized. 3.12.6 Permanent vegetation should replace areas from which gravel, stone, logs, or other materials have been removed. 3.13 Culverts 3.13.1 Sediment accumulated upstream of stream crossings should be removed when the sediment depth is within 6 -inches of the crest (ford crossing) or greater than an average depth of 12 -inches (culvert crossing). 3.13.2 Ford stream crossings should be lined with filter fabric and then layered with a minimum 6 -inch layer of 11/2" inch diameter rock. 3.14 Culvert Inlet and Outlet Protection 3.14.1 When installing and constructing culvert inlet and outlet protection, the use of recycled concrete is not an acceptable substitute for rock. Washington Division Chevron 1100 Date: 4/29/08 EROSION & SEDIMENT CONTROL PICEANCE BASIN NATURAL GAS DEVELOPMENT PROGRAM Doc. No. PBSR-ALLCIV-SPC-URS- 00000-00003-00 Rev: 0 Page: 18 of 17 3.14.2 Sediment accumulated upstream of stream crossings should be removed when the sediment depth is within 6 -inches of the crest (ford crossing) or greater than an average depth of 12 -inches (culvert crossing). 3.15 Concrete Washout Facilities 3.15.1 When establishing onsite concrete washout facilities the following guidelines should be followed: A. Locate washout area at least 50 feet from storm drains, open ditches, or water bodies. B. Avoid creating runoff by draining water to a bermed or level area when washing concrete to remove fine particles and expose the aggregate. C. Post a sign adjacent to each washout facility to inform concrete equipment operators to utilize the proper facilities. D. Do not allow runoff from this area by constructing a temporary pit or bermed area large enough for liquid and solid waste. E. Only concrete from mixer truck chutes should be washed into concrete wash out. F. Once concrete wastes are washed into the designated area and allowed to harden, the concrete should be broken up, removed, and disposed of. 3.15.2 Inspection and Maintenance: A. Inspect concrete washout facilities weekly during the rainy season and on two-week intervals in the non -rainy season to verify continued BMP implementation. B. Temporary concrete washout facilities should be maintained to provide adequate holding capacity with a minimum freeboard of 4 inches for above grade facilities and 12 inches for below grade facilities. C. Maintaining temporary concrete washout facilities should include removing and disposing of hardened concrete and returning the facilities to a functional condition. D. Washout facilities must be cleaned, or new facilities must be constructed and ready for use once the washout is 75 percent full. 3.16 Sanitary/Septic (Port -O -Let) Waste Management 3.16.1 Storage and disposal procedures for sanitary/septic waste management facilities include the following: A. Temporary sanitary facilities should be located away from drainage facilities, watercourses, and from traffic circulation. B. Temporary sanitary facilities should be secured to prevent overturning due to high winds or risk of high winds. C. Only reputable, licensed sanitary and septic waste haulers should be used. Chevron Washington Division Date: 4/29/08 EROSION & SEDIMENT CONTROL PICEANCE BASIN NATURAL GAS DEVELOPMENT PROGRAM Doc. No. PBSR-ALLCIV-SPC-URS- 00000-00003-00 Rev: 0 Page: 77 of 17 D. Sanitary facilities should be located in a convenient location. E. Untreated raw wastewater should never be discharged or buried. F. Regular waste collection by a licensed hauler should be arranged before facilities overflow. 3.16.2 Education: A. Educate employees, subcontractors, and suppliers on sanitary and septic waste storage and disposal procedures. B. Educate employees, subcontractors, and suppliers of potential dangers to humans and the environment from sanitary and septic wastes. C. Instruct employees, subcontractors, and suppliers in identification of sanitary and septic waste. D. Hold regular meetings to discuss and reinforce disposal procedures (incorporate into regular safety meetings). E. Establish a continuing education program to indoctrinate new employees. 3.16.3 Inspection and Maintenance: A. Inspect and verify that activity—based BMPs are in place prior to the commencement of associated activities. B. While activities associated with the BMP are under way, inspect weekly during the rainy season and of two-week intervals in the non -rainy season to verify continued BMP implementation. C. Arrange for regular waste collection. D. If high winds are expected, portable sanitary facilities must be secured with spikes or weighed down to prevent over turning. Rua Rust Constructors Procedure Type PROJECT SAFETY PLAN CHEVRON Piceance Project FUGITIVE DUST CONTROL PLAN Revision No / Status 1 / AFU Procedure No. REC-06 Revision Date 16 December 07 Page 1 of 3 1.0 Purpose: 1.1 This Fugitive Dust Control Plan describes the general control measures to be taken by Rust Constructors Inc. with all Subcontractors creating dust conditions to ensure that dust suppression techniques are implemented to control fugitive dust sources during all construction operations. 1.2 Measures identified in this plan apply to work within the project area defined as the right-of- way, access roads, temporary use areas, facilities and other areas used during construction of the Project. 1.3 All Subcontractor personnel are to be thoroughly familiar with this plan and its contents prior to initiating their construction activities on this Program. 2.0 Requirements for Dust Control 2.1 Each Subcontractor creating fugitive dust conditions is required to provide dust control measures for all areas disturbed by construction. The measures addressed within this section shall be required, as necessary, to control fugitive dust. 2.2 Dust control shall be implemented by each Subcontractor generating dust in areas of active construction, within 500 feet of highways, residences, and power transmission rights-of-way (unless waived by the owner/operator). 2.3 Dust control is required near roadways any time dust stays in the air for 5 minutes or reaches 20 feet in height. 2.4 Dust control shall also be implemented on access roads, as determined by Rust Constructors Inc., and as required by the Contractor for the health and safety of employees. 2.5 Dust control shall be achieved primarily through application of water or an approved dust palliative. Application rates for the dust palliative will follow the manufacturer's recommendations. All dust palliatives used shall be biodegradable. Use of salts with water as a suppressant is limited to magnesium chloride (MC70). 3.0 Control of Unpaved Roads On -Site 3.1 During construction, operation, and maintenance of the project, each Subcontractor shall control vehicle speed to minimize fugitive dust. 3.2 Each Subcontractor shall apply dust suppressants to the construction work area and access roads at the request of Rust Constructors Inc., Client Representatives, the BLM, or county or state representatives. Min Rust Constructors Procedure Type PROJECT SAFETY PLAN CHEVRON Piceance Project FUGITIVE DUST CONTROL PLAN Revision No / Status 1/AFU Procedure No. REC-06 Revision Date 16 December 07 Page 2 of 3 3.3 Subcontractor shall employ control measures or operations procedures including but not limited to, watering, chemical stabilization, road carpeting, paving, suggested speed restrictions and other approved methods and techniques as required to maintain dust control on unpaved roads. 4.0 Control of Paved Roads 4.1 Each Subcontractor shall implement the following requirements on paved roads: a. Construction entrances shall be installed to prevent tracking mud and soil onto paved roads. These entrances shall be constructed as required by county, state, or BLM permits. b. The Subcontractor shall clean any soil tracked onto a paved road that extends more than 50 feet from the point of origin within one hour of discovery. c. Any soil tracked onto a paved road that extends less than 50 feet shall be cleaned up by the end of the working day. d. Additional control measures or operational procedures may include but are not limited to, covering the loaded haul truck, washing or otherwise treating the exterior of the vehicle, limiting the size of the load and the vehicle speed, watering or treating the load with chemical suppressants, and keeping the roadway access point free of materials that may be carried onto the roadway and other approved methods and techniques as required. 5.0 Control of Disturbed Areas On -Site 5.1 During construction, operation, and maintenance of the project, each Subcontractor will suppress dust with application of water or other suppressant as needed, and will control vehicle speed to 15 mph. All areas disturbed by construction will be revegetated in accordance with the Client's Reclamation Plan. 5.2 Each Subcontractor shall apply dust suppressants to the construction work area and access roads at the request of Rust Constructors Inc., Client Representatives, the BLM, and/or county or state representatives. 5.3 Additional control measures or operational procedures for controlling dust during construction activities may include but are not limited to, planting vegetation cover, providing synthetic cover, furrows, and compacting, minimizing disturbed area in winter, wind breaks and other approved methods and techniques as required. RIC Rust Constructors Procedure Type PROJECT SAFETY PLAN CHEVRON Piceance Project FUGITIVE DUST CONTROL PLAN Revision No / Status 1 / AFU Procedure No. REC-06 Revision Date 16 December 07 Page 3 of 3 6.0 Records Records generated shall remain in site files until demobilization at which time they shall be retained in long-term storage. 7.0 Referenced Forms None 8.0 References Colorado Department of Public Health and Environment (CDPHE) Air Pollution Control Division (APCD) Bureau of Land Management "Gold Book", Fourth Edition, 2006 Garfield County Rules and Regulations 9.0 Attachments None URS Washington Division PICEANCE BASIN NATURAL GAS DEVELOPMENT PROGRAM Garfield County, Colorado SPECIFICATION FOR SITE PREPARATION / STABILIZATION, SOIL MANAGEMENT, EARTHWORK, AND BACKFILL Addition of Erosion Control / Soil1 Management Requirements SMC 07/02/08 0 Approved for Construction LOM TM HC 04/15/08 A Issued Preliminary for Review and Comments MN JRV 07/18/07 REV. DESCRIPTION BY CHKD APVD RVWD DATE REVISIONS CLIENT: CHEVRON North America Exploration and Production PROJECT: Piceance Basin Natural Gas Development Program JOB NO.: 29454 DOC NUMBER: PBSR-ALLCIV-SPC-URS-00000-00002-00 H:\_Projects\Chevron\29021_CNAEP\Regulatory\Final Applications\Addendums to SUP Submittal \CPPV 2-0-002_Site Prep, Soil Mgmt, & Eanhwork.doc URS Washington Division Chevron Date: 28Jun08 SITE PREPARATION / STABILIZATION, SOIL MANAGEMENT, EARTHWORK AND BACKFILL PICEANCE BASIN NATURAL GAS DEVELOPMENT PROGRAM Doc. No. PBSR-ALLCIV-SPC-URS- 00000-00002-00 Rev: 1 Page: 1 of 8 TABLE OF CONTENTS SECTION PAGE 1. SCOPE 1 2. DEFINITIONS 1 3. REQUIRED REFERENCES 1 4. DOCUMENTS 2 5. REPORTS 2 6. SPECIFICATIONS 2 7. SITE EVALUATION / EXISTING VEGETATION DOCUMENTATION 3 8. CLEARING / GRUBBING / DRAINAGE / PRELIMINARY EROSION CONTROL 3 9. TOPSOIL REMOVAL / MANAGEMENT 4 10. EXCAVATION - GENERAL 4 11. FILL / BACKFILL / COMPACTION 5 12. QUALITY ASSURANCE 6 13. ADDITIONAL REQUIREMENTS FOR TANK SUBGRADE 7 14. GRADING 7 15. ADDITIONAL REQUIREMENTS FOR ROADWAY SUBGRADE 8 1 URS Washington Division Chevron 410 110 Date: 28Jun08 SITE PREPARATION / STABILIZATION, SOIL MANAGEMENT, EARTHWORK AND BACKFILL PICEANCE BASIN NATURAL GAS DEVELOPMENT PROGRAM Doc. No. PBSR-ALLCIV-SPC-URS- 00000-00002-00 Rev: 1 Page: 1 of 8 1. SCOPE 1.1 This scope covers the requirements for site preparation, soil management, general earthwork, preparation of tank sub -grades and tank dikes. 2. DEFINITIONS 2.1 Owner: Chevron North America Exploration and Production 2.2 Engineer: URS Corporation Washington Division 2.3 Contractor: TBD 2.4 Subcontractor: Firm undertaking the scope of work as defined in this Specification 2.5 State: Refers to State of Colorado 3. REQUIRED REFERENCES This Section lists Standards, Codes and Specifications that are referenced and assumed to be a part of this document. Unless otherwise specified herein, use the latest edition. 3.1 ASTM—American Society for Testing and Materials ASTM C 33-03 Standard Specification for Concrete Aggregates. ASTM C 117 - 04 Standard Test Methods for Material Finer Than # 200 Sieve in Aggregates by Washing. ASTM C 136-06 Standard Test Method for Sieve Analysis of Fine and Coarse Aggregates. ASTM D 422-63 Standard Test Method for Particle -size Analysis of Soils. ASTM D 1140 Standard Test Methods for Amount of Material in Soils Finer Than the No. 200 (75 -Micrometer) Sieve ASTM 1556 Standard Method for Density and Unit Weight of Soil in Place by the Sand Cone method. ASTM D 1557 Standard Test Methods for Laboratory Compaction Characteristics of Soil Using Modified Effort (56,000 ft-Ibf/ft3 (2,700 kN-m/m3)) ASTM D 2167 Standard Test Method for Density and Unit Weight of Soil in Place by the Rubber Balloon Method ASTM D 2216 Standard Test Methods for Laboratory Determination of Water (Moisture) 1 URS Washington Division Chevron 114014 111100 Date: 26Jun08 SITE PREPARATION / STABILIZATION, SOIL MANAGEMENT, EARTHWORK AND BACKFILL PICEANCE BASIN NATURAL GAS DEVELOPMENT PROGRAM Doc. No. PBSR-ALLCIV-SPC-URS- 00000-00002-00 Rev: 1 Page: 2 of a 4. DOCUMENTS Typical Best Management Practices (BMPs) Details, URS Document Number: PBSR-ALL-RGL-PMT- URS-00000-00003-00. Chevron Piceance Basin Natural Gas Development Program, Storm -Water Management Plan, Construction Storm -Water Field Permit, URS Document Number: PBSR-ALL-RGL-PMT-URS-00000- 00002-00 and PBSR-ALL-RGL-PMT-URS-00000-00002-00. Rust Constructors, Chevron Piceance Project, Project Safety Plan, Fugitive Dust Control Plan, Rev. 1, Procedure Number: REC-06. 5. REPORTS 1.1 Geotechnical Investigation for facility specific area. 6. SPECIFICATIONS 6.1 12-0-001 Civil Design Basis 6.2 12-0-003 Erosion and Sediment Control 6.3 12-0-004 Re -Vegetation of Disturbed Areas 6.4 12-0-005 Aggregate Base Course 6.5 12-0-007 Fences and Gates 2 Content of Soil and Rock by Mass. ASTM D 2922 Standard Test Methods for Density of Soil and Soil -Aggregate in Place by Nuclear Methods (Shallow Depth) ASTM D 2937 Standard Test Method for Density of Soil in Place by the Drive -Cylinder Method ASTM D 3017-05 Standard Method for Water Content of Soil and Rock in Place by Nuclear Methods (Shallow Depth) ASTM D 4253 Standard Test Methods for Maximum Index Density and Unit Weight of Soils Using a Vibratory Table ASTM D 4254 Standard Test Methods for Minimum Index Density and Unit Weight of Soils and Calculation of Relative Density ASTM D 4318 Standard Test Methods for Liquid Limit, Plastic Limit, and Plasticity Index of Soils 4. DOCUMENTS Typical Best Management Practices (BMPs) Details, URS Document Number: PBSR-ALL-RGL-PMT- URS-00000-00003-00. Chevron Piceance Basin Natural Gas Development Program, Storm -Water Management Plan, Construction Storm -Water Field Permit, URS Document Number: PBSR-ALL-RGL-PMT-URS-00000- 00002-00 and PBSR-ALL-RGL-PMT-URS-00000-00002-00. Rust Constructors, Chevron Piceance Project, Project Safety Plan, Fugitive Dust Control Plan, Rev. 1, Procedure Number: REC-06. 5. REPORTS 1.1 Geotechnical Investigation for facility specific area. 6. SPECIFICATIONS 6.1 12-0-001 Civil Design Basis 6.2 12-0-003 Erosion and Sediment Control 6.3 12-0-004 Re -Vegetation of Disturbed Areas 6.4 12-0-005 Aggregate Base Course 6.5 12-0-007 Fences and Gates 2 URS Washington Division Chevron Date: 28Jun08 SITE PREPARATION / STABILIZATION, SOIL MANAGEMENT, EARTHWORK AND BACKFILL PICEANCE BASIN NATURAL GAS DEVELOPMENT PROGRAM Doc. No. PBSR-ALLCIV-SPC-URS- 00000-00002-00 Rev: Page: 3 of 8 6.6 12-0-009 Excavation, Backfilling and Compaction for Utilities 7. SITE EVALUATION / EXISTING VEGETATION DOCUMENTATION 7.1 The site shall be evaluated to determine potential problem areas for control of storm -water runoff. Erosion control drawings, the master storm -water management plan, and the site specific storm - water management plan shall be reviewed prior to any land disturbance activities. 7.2 Photos of existing site conditions shall be obtained to document pre -construction vegetative cover. This information is needed to determine when the site has reached sufficient re -vegetative cover to meet regulatory requirements. Pre -construction site photos shall be provided to the on- site storm -water management plan coordinator. 8. CLEARING / GRUBBING / DRAINAGE / PRELIMINARY EROSION CONTROL 8.1 All earthwork construction shall be evaluated for erosion potential and appropriate controls measures (Best Management Practices — BMPs) shall be specified / installed the potential for soils erosion, measures shall be taken to mitigate such erosion, when specified. Refer to URS Documents: PBSR-ALL-RGL-PMT-URS-00000-00002-00 and PBSR-ALL-RGL-PMT-URS-00000- 00003-00 and Specification 12-0-003. 8.1.1 Preliminary erosion controls (e.g., silt fencing, straw wattles, berms, etc.) shall be installed as soon as sufficient vegetation has removed to allow installation. Some areas with high erosion risk may require the installation of several interim control measures. 8.2 Active dust control methods shall be implemented, as necessary, throughout the clearing and grubbing operations. Dust control procedures for this project are documented in the Rust Constructors, Chevron Piceance Project, Project Safety Plan, Fugitive Dust Control Plan, Rev. 1, Procedure Number: REC-06. 8.3 Clearing, at the specified site work areas, shall include the removal of all trees, bushes, and other vegetation. It shall also include the removal of dense growth of ground plants, matted dead vegetation and rubbish resting on natural grade. 8.4 Clearing shall include the specified (as identified on the drawings) removal of any existing structures, foundations, buried service piping and conduits. 8.5 Grubbing, at the specified site work areas, shall include the excavation and complete removal of tree stumps. Grubbing also shall include the excavation and complete removal of all other plant life, including root structures, plus rubbish. 8.6 Exceptions to the depth for grubbing are as follows for the specific site work areas shown below: 8.6.1 Drainage ditches shall be grubbed to a depth no less than one (1) foot (300 mm) beneath the finished side slopes and bottom. 3 URS Washington Division Chevron 410 11140. Date: 28Jun08 SITE PREPARATION / STABILIZATION, SOIL MANAGEMENT, EARTHWORK AND BACKFILL PICEANCE BASIN NATURAL GAS DEVELOPMENT PROGRAM Doc. No. PBSR-ALLCIV-SPC-URS- 00000-00002-00 Rev: Page: 4 of 8 8.6.2 Areas directly under tanks shall be grubbed to a depth of two (2) feet (600 mm) below the tank bottom but not less than six (6) inches (150 mm) below natural grade over the entire tank bottom. 8.6.3 Areas under earth dikes for tanks and pit areas around tanks shall be grubbed to a depth of two (2) feet (600 mm) below finished grade but not less than six (6) inches (150 mm) below natural grade. 8.6.4 Embankment slopes shall be grubbed to a depth of at least one (1) foot (300 mm) beneath the finished slope. 8.6.5 Areas for piping between unit area limits and ditches, and along roads, shall be grubbed to a depth of two (2) feet (600 mm) below finished grade but not less than six (6) inches. (150 mm) below natural grade. 8.6.6 All organic material, including trees, stumps, roots, and brush shall be removed from the site work areas as directed by the Contractor. 8.7 All storm -water controls should be inspected for functional integrity following clearing and grubbing operations and repaired as necessary. 9. TOPSOIL REMOVAL / MANAGEMENT 9.1 Topsoil is an extremely valuable resource necessary for re -vegetation activities that are mandated by several regulatory agencies (CDPHE, COGCC, Garfield County). Because topsoil formation is a very slow process [ranges from <0.25 mm per year for cold, dry climates (similar to Colorado) to >1.5 mm per year in humid, warm climates], every effort shall be made to conserve existing topsoil by careful excavation and placement in a dedicated topsoil stockpile. 9.2 Appropriate interim and permanent erosion control measures shall be installed on the topsoil stockpile, as soon as practical, to protect the topsoil resource from wind and water erosion. 9.3 Active dust control methods shall be implemented, as necessary, throughout all topsoil removal and stockpiling operations. Dust control procedures for this project are documented in the Rust Constructors, Chevron Piceance Project, Project Safety Plan, Fugitive Dust Control Plan, Rev. 1, Procedure Number: REC-06. 9.4 A vegetative cover shall be established on the topsoil stockpile (or equivalent control technique) to stabilize the resource until it is needed for site reclamation / re -vegetation. 9.5 All storm -water controls should be inspected for functional integrity following topsoil stockpiling operations and repaired as necessary. 10. EXCAVATION - GENERAL 10.1 All excavation activities shall be reviewed to determine if erosion control measures are necessary. Appropriate erosion interim and/or permanent controls shall be installed as soon as practical. 4 Washington Division Chevron IMO Date: 28Jun08 SITE PREPARATION / STABILIZATION, SOIL MANAGEMENT, EARTHWORK AND BACKFILL PICEANCE BASIN NATURAL GAS DEVELOPMENT PROGRAM Doc. No. PBSR-ALLCIV-SPC-URS- 00000-00002-00 Rev: Page: 5 of 8 10.2 Active dust control methods shall be implemented, as necessary throughout all excavation operations. Dust control procedures for this project are documented in the Rust Constructors, Chevron Piceance Project, Project Safety Plan, Fugitive Dust Cont of Plan, Rev. 1, Procedure Number: REC-06. 10.3 Rock, if encountered in pipe trenches, shall be removed to at least six (6) inches (150 mm) below bottom of pipe. 10.4 If trench bottom materials are soft, they shall be stabilized as recommended by the appropriate geotechnical firm representative. One potential method of stabilization included the soft zone be removed and replaced with coarse granular material, leveled and compacted to the prescribed grade. 10.5 If soft or unstable materials are encountered near the bottom of a foundation excavation, the Contractor shall be advised immediately. Measures taken to remedy such conditions shall be approved by the geotechnical firm representative. 10.6 If a structure or foundation is founded on rock, the rock shall be stripped clean and cut level, stepped or serrated. Foundations shall not be supported by mixed foundation types or mixed ground support strata. 10.7 Excavated materials shall be disposed of as fill if suitable or transported to designated contractor spoil or stockpile areas. 10.8 Foundation excavations shall be kept free of water until either a seal slab or the foundation is placed. Any water -softened soils shall be removed prior to pouring the foundation. 10.9 Where the locations of existing underground utilities are not known, controlled localized excavation shall be made to identify their location prior to general excavation. 10.10 Remove all existing organic material and soil to a minimum depth of four (4) inches. 10.11 Scarify, moisture condition, and re -compact exposed soil to a minimum depth of 12 inches. 10.12 All storm -water controls should be inspected for functional integrity following excavation activities and repaired as necessary. 11. FILL / BACKFILL / COMPACTION All fill / backfill / compaction activities shall be reviewed to determine if erosion control measures are necessary. Appropriate erosion interim and/or permanent controls shall be installed as soon as practical. 11.2 Active dust control methods shall be implemented, as necessary, throughout all fill / backfill / compaction operations. Dust control procedures for this project are documented in the Rust Constructors, Chevron Piceance Project, Project Safety Plan, Fugitive Dust Control Plan, Rev. 1, Procedure Number: REC-06. 5 URS Washington Division Chevron 114011 Date: 28Jun08 SITE PREPARATION / STABILIZATION, SOIL MANAGEMENT, EARTHWORK AND BACKFILL PICEANCE BASIN NATURAL GAS DEVELOPMENT PROGRAM Doc. No. PBSR-ALLCIV-SPC-URS- 00000-00002-00 Rev: 1 Page: 6 of 8 11.3 Native overburden and excavated, consisting of four (4) inches well graded maximum 15 -percent passing the No. 200 sieve, maximum liquid limit 30 -percent, and six (6) inch maximum coarse rock, may be used for Granular Structural Fill. 11.4 Coarse aggregate structural fill shall to be placed around finished pile caps. 11.5 Top layer is to consist of 3 inch and smaller gravel placed at sub -grade elevation. 11.6 All fill and backfill should be placed in uniform lifts, moisture content adjusted between two percent below optimum moisture content to two percent above optimum moisture and compacted to the following minimum percent of maximum dry density as determined by ASTM D698 (standard Proctor) A. Foundations, Skids, PDC's 95% B. Building Floor Slabs 95% C. Condensate Storage/Produced Liquid Tanks 95% D. General Backfill 90% E. Roads storage areas and any traveled surface. 95% 11.7 Work lay down area top layer is to consist of 18 inches of one (1) inch maximum size aggregate base course gravel placed at sub -grade elevation. At least 12 inches of well compacted granular fill will produce a maximum bearing pressure of 1,750 pounds per square foot (psf). Bearing pressures over 1,750 psf, foundation dimensions over 60 -inches or structures with settlement tolerances less than four (4) inches movement require structure geotechnical analysis and may require deep foundations, such as driven piles. 11.8 All storm -water controls should be inspected for functional integrity following fill / backfill / compaction activities and repaired as necessary. 12. QUALITY ASSURANCE 12.1 All soil testing shall be performed by a representative of the appropriate geotechnical firm. 12.2 At least one optimum moisture -maximum density curve for each class of soil will be prepared. The exact number of tests shall be dependent on the variation of material properties for each class of soil, and shall be determined by the soil engineer. 12.3 Maximum densities: Determined based on ASTM D698, standard Proctor. 12.4 Quality assurance testing during construction shall be performed using in-place density test per ASTM D 1557, ASTM D 2167 or ASTM 2922 or ASTM D 4253/4254 for non -cohesive material. 12.5 Location of test will be determined be the appropriate geotechnical firm representative. 12.6 Minimum Test Frequency: 6 URS Washington Division Chevron 1100 Date: 28Jun08 SITE PREPARATION / STABILIZATION, SOIL MANAGEMENT, EARTHWORK AND BACKFILL PICEANCE BASIN NATURAL GAS DEVELOPMENT PROGRAM Doc. No. PBSR-ALLCIV-SPC-URS- 00000-00002-00 Rev: 1 Page: 7 of 8 A. Minimum of three tests shall be performed under each facility / equipment foundation. Additional test requirements for foundations include: One for each independent foundation or one every 1000 square feet of each lift. B. Under area paving and building slab areas: One every 2,000 square feet of each lift but in no case less than three tests. C. Road base and sub -base: One every 2,000 square feet of each lift. D. Trench Backf ill: One test for every 50 linear feet of each lift. E. General fill: One every 2,000 square feet of each lift. 12.7 Quality Assurance Tests: When a test indicates results below specified density, the Subcontractor shall re -compact the area to the proper density and pay for the re -testing expense. 12.8 Compaction test locations serve as an indication and not a guarantee that compacted areas meet the minimum requirements, however the Subcontractors remains responsible that all soils meet at least the minimum requirements. 13. ADDITIONAL REQUIREMENTS FOR TANK SUBGRADE 13.1 Earth subgrade under tank subgrade shall be prepared as follows: 13.1.1 Remove any rock found under the tank bottom or within two (2) feet (600 mm) of the tank bottom. 13.1.2 Sub -grade shall be proof -rolled using overlapping passed with a loaded dump truck or heavy compactor prior to fill placement or construction. Any soft material encountered shall be removed and the excavation area backfilled and compacted as by the soil Engineer. 14. GRADING 14.1 All rough grading activities shall be reviewed to determine if erosion control measures are necessary. Appropriate erosion interim and/or permanent controls shall be installed as soon as practical. 14.2 Active dust control methods shall be implemented, as necessary, throughout all rough grading operations. Dust control procedures for this project are documented in the Rust Constructors, Chevron Piceance Project, Project Safety Plan, Fugitive Dust Control Plan, Rev. 1, Procedure Number: REC-06. 14.3 Rough grading shall be installed to within a vertical tolerance of 0.2 foot (60 mm) of final lines, grades and slopes. 14.4 Final grades shall be carried to the lines, grades and slopes shown on the drawings, within a • tolerance of 0.1 foot (30 mm). 7 URS Washington Division Chevron IMO Date: 28Jun08 Rev: SITE PREPARATION / STABILIZATION, SOIL MANAGEMENT, EARTHWORK AND BACKFILL PICEANCE BASIN NATURAL GAS DEVELOPMENT PROGRAM Doc. No. P B S R -A LLC I V -SPC -U R 5- 00000-00002-00 Page: 8 of 8 14.5 All storm -water controls should be inspected for functional integrity following rough grading activities and repaired as necessary. 15. ADDITIONAL REQUIREMENTS FOR ROADWAY SUBGRADE 15.1 The existing sub -grade shall be compacted by proof -rolling and any soft material removed prior to placing fill, sub -base or base course materials 15.2 Remove any rock that protrudes above the final road bed sub -grade or above the face of the side ditches. Tolerance for the bottom of road to be ± four (4) inches from finish grade. 8