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1.04 General Application Materials_Part5
Wheeler Gulch Solar Project B Storm Water Management Permit Wheeler Gulch Solar Project This page intentionally left blank. 4300 Cherry Creek Drive South, Denver, CO 80246 303-692-3500 www.colorado.gov/cdphe/wqcd CERTIFICATION TO DISCHARGE UNDER CDPS GENERAL PERMIT COR400000 STORMWATER ASSOCIATED WITH CONSTRUCTION ACTIVITIES Certification Number: COR400643 This Certification to Discharge specifically authorizes: Owner Caerus Piceance LLC Operator Caerus Piceance LLC to discharge stormwater from the facility identified as NPR Caerus To the waters of the State of Colorado, including, but not limited to: Garden Gulch, Parachute Creek Facility Activity : Oil and Gas Exploration and Well Pad Development Disturbed Acres: 200 acres Facility Located at: Parachute Creek and Garden Gulch Uninc CO 81650 Garfield County Latitude 39.51666 Longitude -108.1666 Specific Information (if applicable): Certification is issued and effective: 9/6/2019 Expiration date of general permit: 3/31/2024 This certification under the permit requires that specific actions be performed at designated times. The certification holder is legally obligated to comply with all terms and conditions of the permit. This certification was approved by: Meg Parish, Section Manager Permits Section Water Quality Control Division 4300 Cherry Creek Drive South, Denver, CO 80246 303-692-3500 www.colorado.gov/cdphe/wqcd Lindsey Rider, EH&S Lead Caerus Piceance LLC 143 Diamond Ave Parachute, CO 81635 Lindsey Rider, EH&S Lead Caerus Piceance LLC 143 Diamond Ave Parachute, CO 81635 DATE: 2019-09-06 MEMO RE: Modification Certification, Colorado Discharge Permit System Permit No., COR400000, Certification Number: COR400643 DIVISION CONTACTS: Joseph Sturgeon, 303-691-4019, Joseph.Sturgeon@state.co.us ATTACHMENTS: Certification COR400643 On 2019-09-06 the Water Quality Control Division received a request to modify this certification by: update permit information. The Water Quality Control Division (the Division) has reviewed the application submitted for the NPR Caerus facility and determined that it qualifies for coverage under the CDPS General Permit for Stormwater Discharges Associated with Construction Activities (the permit). Enclosed please find a copy of the permit certification, which was issued under the Colorado Water Quality Control Act. FEE INFORMATION: 200 acres There is no fee It is the responsibility of the permittee to submit a termination application when the permit is no longer needed. Fees are assessed and invoiced for every permit that is active July 1 of the fiscal year. Permits for which termination applications are received by June 30 of the current fiscal year will not be invoiced for the new fiscal year. CERTIFICATION RECORDS INFORMATION: The following information is what the Division records show for this certification. For any changes to Contacts – Owner, Operator, Facility, or Billing – a “Notice of Change of Contacts form” must be managed through the Division’s new platform called the Colorado Environmental Online Services (CEOS). The Notice of Change of Contacts form must be electronically signed by both the owner and the operator. Facility: NPR Caerus Garfield County Construction Activities Oil and Gas Exploration and Well Pad Development Owner (receives all legal documentation pertaining to the permit certification): Lindsey Rider, EH&S Lead Caerus Piceance LLC 143 Diamond Ave Parachute, CO 81635 Phone number: 970-285-2711 Email: lrider@caerusoilandgas.com Operator (receives all legal documentation pertaining to the permit certification): Lindsey Rider, EH&S Lead Caerus Piceance LLC 143 Diamond Ave Parachute, CO 81635 Phone number: 970-285-2711 Email: lrider@caerusoilandgas.com Facility Contact (contacted for general inquiries regarding the facility): Kathy Vertiz, Environmental Consultant Caerus Piceance LLC 143 Diamond Ave Parachute, CO 81635 Phone number: 970-812-7560 Email: kvertiz@caerusoilandgas.com Billing Contact (receives the invoice pertaining to the permit certification): Lindsey Rider, EH&S Lead Caerus Piceance LLC 143 Diamond Ave Parachute, CO 81635 Phone number: 970-285-2711 Email: lrider@caerusoilandgas.com 4300 Cherry Creek Drive South, Denver, CO 80246 303-692-3500 www.colorado.gov/cdphe/wqcd R CERTIFICATION TO DISCHARGE UNDER CDPS GENERAL PERMIT COR400000 STORMWATER ASSOCIATED WITH CONSTRUCTION ACTIVITIES Certification Number: COR400643 This Certification to Discharge specifically authorizes: Owner Caerus Piceance LLC Operator Caerus Piceance LLC to discharge stormwater from the facility identified as Piceance Area To the waters of the State of Colorado, including, but not limited to: to Garden Gulch to Parachute Creek Facility Activity : Oil and gas production Disturbed Acres: 200 acres Facility Located at: Parachute Creek and Garden Gulch Uninc CO 81650 Garfield County Latitude 39.51666 Longitude -108.1666 Specific Information (if applicable): Certification is issued 4/1/2019 Certification is effective 4/1/2019 Expiration date of general permit : 3/31/2024 This certification under the permit requires that specific actions be performed at designated times. The certification holder is legally obligated to comply with all terms and conditions of the permit. This certification was approved by: Meg Parish, Unit Manager Permits Section Water Quality Control Division Michael Rynearson, Ops VP Caerus Piceance LLC 1001 17 St Ste 1600 Denver, CO 80202 DATE: 12/19/2017 MEMO RE: Transfer of Certification, Colorado Discharge Permit System Permit No., COR030000, Certification Number: COR03C052 DIVISION CONTACTS: Debbie Jessop 303-692-3590 ATTACHMENTS: Certification General Permit On 12/18/2017, the Division received a request to transfer the certification for Piceance Area from Marathon Oil Co to Caerus Piceance LLC and determined that it qualifies for coverage under the CDPS General Permit for Stormwater Discharges Associated with Construction (the permit). FEE INFORMATION: The Annual Fee for this certification is $350 [category 7, subcat II-J Construction Stormwater Construction 1-30 acres per CRS 25-8- 502]. This will be invoiced in July. CERTIFICATION RECORDS INFORMATION: The following information is what the Division records show for this certification. For any changes to Contacts – Legal, Facility, or Billing – a “Notice of Change of Contacts form” must be submitted to the Division. This form is also available on our web site and must be signed by the legal contact. Facility: Piceance Area GarfieldCounty Construction Activities Oil and gas production Legal Contact (receives all legal documentation pertaining to the permit certification): Michael Rynearson, Ops VP Caerus Piceance LLC 1001 17 St Ste 1600 Denver, CO 80202 Phone number: 720-880-6407 Email: mrynearson@caerusoilandgas.com Facility Contact (contacted for general inquiries regarding the facility): Michael McKee,EHS Engr Caerus Piceance LLC 1001 17 St Ste 1600 Denver, CO 80202 Phone number: 720-880-6322 Email: mmckee@caerusoilandgas.com Billing Contact (receives the invoice pertaining to the permit certification): Michael McKee, EHS Engr Caerus Piceance LLC 1001 17 St Ste 1600 Denver, CO 80202 Phone number: 720-880-6322 Email: mmckee@caerusoilandgas.com ADMINISTRATIVE CONTINUATION EXPLANATION: The Division is currently developing a renewal permit and associated certification for the above permitted facility. The development and review procedures required by law have not yet been completed. The Construction Stormwater General Permit, which expired June 30, 2012, is administratively continued and will remain in effect under Section 104(7) of the Administrative Procedures Act, C.R.S. 1973, 24-4-101, et seq (1982 repl. vol. 10) until a renewal permit/certification is issued and effective. The renewal for this facility will be based on the application that was received 12/18/2017 All effluent limits, terms and conditions of the administratively continued permit are in effect until the renewal is complete. 4300 Cherry Creek Drive S., Denver, CO 80246-1530 P 303-692-2000 www.colorado.gov/cdphe John W. Hickenlooper, Governor | Larry Wolk, MD, MSPH, Executive Director and Chief Medical Officer CERTIFICATION TO DISCHARGE UNDER CDPS GENERAL PERMIT COR-0300000 STORMWATER ASSOCIATED WITH CONSTRUCTION ACTIVITIES Certification Number: COR03C052 This Certification to Discharge specifically authorizes: Caerus Piceance LLC to discharge stormwater from the facility identified as Piceance Area To the waters of the State of Colorado, including, but not limited to: Garden Gulch- Parachute Creek Facility Industrial Activity : Oil and gas production Facility Located at: Parachute Creek and Garden Gulch Uninc CO 81650 Garfield County Latitude 39.51666 Longitude -108.1666 Specific Information (if applicable): Disturbed Acreage >5 acres Total Acreage >5 acres Modified and reissued date: 12/18/2017 Effective date: 12/18/2017 Expiration date: This authorization expires upon effective date of the General Permit COR030000 renewal unless otherwise notified by the division. Modification # 1 transferred permit from Marathon Oil Co to Caerus Piceance LLC This certification under the permit requires that specific actions be performed at designated times. The certification holder is legally obligated to comply with all terms and conditions of the permit. This certification was approved by: Lillian Gonzalez, Unit Manager Permits Section Water Quality Control Division Page 1 of 2 form last revised December 2011 DIVISION USE ONLY WQCD Division Initiated Modification Requested by___________ Date requested__________ Date entered____________ MODIFICATION APPLICATION Please print or type all information. All items must be filled out completely and correctly. If the form is not complete, it will be returned. All modification dates are established by the Division. This form is for modifying an established permit or certification. Terminations, Change of Contacts, Transfer of Permit, and Withdrawl of Permit Application and/or modification requests must be submitted on the appropriate form: MAIL ORIGINAL FORM WITH INK SIGNATURES TO THE FOLLOWING ADDRESS: Colorado Dept of Public Health and Environment Water Quality Control Division 4300 Cherry Creek Dr South WQCD-P-B2 Denver, CO 80246-1530 FAXED or EMAILED FORMS WILL NOT BE ACCEPTED. • PART A. IDENTIFICATION OF PERMIT Please write the permit number to be modified PERMIT NUMBER _________________________ • PART B. PERMITEE INFORMATION (application must be signed by the legal contact listed here) Company Name Mailing Address City State Zipcode Legal Contact Name Phone Number Title Email • PART C. FACILITY/PROJECT INFORMATION Facility/Project Name Location (address) City County Local Contact Name Phone Number Title Email COLORADO WATER QUALITY CONTROL DIVISION MODIFICATION APPLICATION www.coloradowaterpermits.com Page 2 of 2 form last revised December 2011 •PART D. DESCRIPTION OF MODIFICATION REQUESTED: •PART E. CERTIFICATION Required Signatures “I certify under penalty of law that I have personally examined and am familiar with the information submitted in this application and all attachments and that, based on my inquiry of those individuals immediately responsible for obtaining the information, I believe that the information is true, accurate and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine or imprisonment. “I understand that submittal of this application is for coverage under the State of Colorado Discharge Permit System until such time as the application is amended or the certification is transferred, inactivated, or expired.” Signature of Legally Responsible Party Date Signed Name (printed) Title *This modification application shall be signed, dated, and certified for accuracy by the permittee. In all cases, it shall be signed as follows: 1.In the case of a corporation, 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 operation from which the discharge described herein originates; 2.In the case of a partnership, by a general partner; 3.In the case of a sole proprietorship, by the proprietor; 4.In the case of a municipal, state, or other public operation, by either a principal executive officer, ranking elected official, or other duly authorized employee. If adding outfalls to an existing permit, include outfall number, latitude and longitude of the outfall, flow, receiving waters, and any treatment (see application for new permit for guidance). W e s t F o r k East Fork E Midd l e F o r k Northw a t e r C r e e k Trappe r C r e e k Parachute Creek Co n n C r e e k D a v i s G u l c h Alle n w a t e r C r e e k Wh e e l e r G u l c h De e p G u l c h F o r k e d G u l c h Cor r a l G u l c h Litt l e C r e e k Wi l l o w C r e e k She e p K i l l G u l c h Sc h a t t e C r e e k Garden G u l c h Ca s c a d e C a n y o n Sp r i n g G u l c h Hous e L o g G u l c h Bull Gulc h Wolf C r e e k Circ l e D o t G u l c h Cry s t a l C r e e k C a c h e C r e e k Tr a i l G u l c h Starke y G u l c h First An v i l C r e e k Gard n e r G u l c h Bake r G u l c h H e l m G u l c h Gr a s s y G u l c h Mi d d l e W a t e r Ras p b e r r y C r e e k Red G u l c h Cabi n W a t e r Be a r C a b i n G u l c h Mid d l e F o r k JV G u l c h Sheep Gulch Ca m p G u l c h W F o r k e d G u l c h R u l i s o n G u l c h C o t t o n w o o d G u l c h Bear R u n T i m b e r G u l c h P e t e S p r i n g G u l c h S h o r t W a t e r W e s t F o r k Cot t o n w o o d G u l c h East For k Pa r a c h u t e C r e e k Gr a s s y G u l c h M i d d l e F o r k 5 S 95 W 6 S 96 W 6 S 95 W 5 S 96 W 5 S 94 W 6 S 97 W 6 S 94 W 5 S 97 W 4 S 96 W 7 S 97 W 4 S 97 W 7 S 94 W 4 S 95 W 7 S 95 W 4 S 94 W 7 S 96 W Copyright:© 2013 National Geographic Society, i-cubed Legend TWN_CO NPR µ Colordo Discharge Permit NPRCOR03C052 Wheeler Gulch Solar Project This page intentionally left blank. Wheeler Gulch Solar Project C Biological Resources Report Wheeler Gulch Solar Project This page intentionally left blank. 1670 Broadway, Suite 3400, Denver, CO 80202-4824 (303) 764-1520 hdrinc.com Biological Resources Report Caerus Operating, LLC Wheeler Gulch Solar Project Prepared for: Prepared by: December 2022 Caerus Operating, LLC | Garfield County, Colorado Wheeler Gulch Solar Project BIOLOGICAL RESOURCES REPORT 1670 Broadway, Suite 3400, Denver, CO 80202-4824 (303) 764-1520 hdrinc.com This page intentionally left blank. 1670 Broadway, Suite 3400, Denver, CO 80202-4824 (303) 764-1520 hdrinc.com i Table of Contents 1. Introduction ......................................................................................................................... 1 1.1. Project Description ....................................................................................................... 1 1.2. Environmental Setting .................................................................................................. 1 2. Methods .............................................................................................................................. 2 3. Results ................................................................................................................................ 2 3.1. Threatened and Endangered Species .......................................................................... 2 3.1.1. Mexican Spotted Owl ............................................................................................ 4 3.1.2. Yellow-billed Cuckoo ............................................................................................. 5 3.1.3. Bonytail ................................................................................................................. 5 3.1.4. Colorado Pikeminnow ........................................................................................... 5 3.1.5. Humpback Chub ................................................................................................... 5 3.1.6. Razorback Sucker ................................................................................................ 6 3.1.7. Monarch Butterfly .................................................................................................. 6 3.1.8. Gray Wolf .............................................................................................................. 7 3.1.9. Debeque phacelia ................................................................................................. 7 3.1.10. Parachute beardtongue ........................................................................................ 7 3.1.11. Ute-ladies’ Tresses ............................................................................................... 7 3.2. Other Federally Listed Species .................................................................................... 7 3.2.1. Migratory Bird Treaty Act ...................................................................................... 7 3.2.2. Bald and Golden Eagle Protection Act .................................................................. 8 3.3. State-Listed Species .................................................................................................... 9 3.4. Big Game Species ......................................................................................................10 3.5 Noxious Weeds ............................................................................................................11 4. Impact Evaluation and Recommendations .........................................................................11 4.1. Threatened and Endangered Species .........................................................................11 4.2. Migratory Birds ............................................................................................................11 4.3. Bald and Golden Eagles .............................................................................................12 4.4. State-Listed Species ...................................................................................................12 4.5. Big Game Species ......................................................................................................12 4.6 Noxious Weeds .............................................................................................................12 5. CPW Recommendations ....................................................................................................13 6. References ........................................................................................................................14 Caerus Operating, LLC | Garfield County, Colorado Wheeler Gulch Solar Project BIOLOGICAL RESOURCES REPORT 1670 Broadway, Suite 3400, Denver, CO 80202-4824 (303) 764-1520 hdrinc.com ii Appendices Appendix A: Figures Appendix B: IPaC Report Caerus Operating, LLC | Garfield County, Colorado Wheeler Gulch Solar Project BIOLOGICAL RESOURCES REPORT 1670 Broadway, Suite 3400, Denver, CO 80202-4824 (303) 764-1520 hdrinc.com 1 1. Introduction On behalf of Caerus Operating, LLC (Caerus) HDR Engineering, Inc. (HDR) conducted a biological and ecological resources analysis for a proposed solar project in Garfield County, Colorado (Appendix A, Figure 1). This report details the survey results and analyzes potential impacts on federally listed threatened and endangered species (TES) legally protected by the Endangered Species Act (ESA) of 1973 (16 United States Code [U.S.C.] 35 §1531-1543), migratory birds protected under the Migratory Bird Treaty Act (MBTA), state-listed threatened and endangered species (Nongame and Endangered Species Conservation § 33-2-105), and other sensitive species managed by Colorado Parks and Wildlife (CPW). For information on survey results for waters of the U.S., refer to the forthcoming Aquatic Resource Delineation Report. Based on impacts to potential waters of the U.S., either an internal memorandum or U.S. Army Corps of Engineers Pre-Construction Notification will be prepared to identify impacts to aquatic resources, including waters of the U.S. 1.1. Project Description Caerus is proposing the construction of a solar facility (Appendix A, Figure 1) approximately three miles northwest of Parachute, Colorado between Parachute Creek and County Road 215. The project area is an approximately 88-acre parcel in Garfield County in Township 6S Range 96W Sections 33 and 34. 1.2. Environmental Setting The biological resources study area (study area) is defined by a ½-mile buffer of the proposed solar project. The study area is in a valley within the Roan Cliffs. It is closely bounded by Parachute Creek on the southwestern side and County Road 215 on the northeastern side. The major land uses within the study area are industrial, agricultural, and rangeland. The dominant land cover in the study area is shrub/ scrub, which makes up 56 percent of the study area (Appendix A, Figure 2). Evergreen forest is the next largest land cover at 18 percent followed by developed land at 16 percent. The remaining land cover consists mainly of pasture/ hay fields, woody wetlands, barren land, and cultivated crops (NLCD 2019). The study area is located within the Colorado Plateaus Level III ecoregion (Chapman et al. 2006). The study area is split between two level IV ecoregions: 1) Shale Deserts and Sedimentary Basins and 2) Escarpments. The Shale Deserts and Sedimentary Basins ecoregion runs down the center of the study area along the valley. The Shale Deserts and Sedimentary Basins are characterized by the following: Nearly level basins and valleys, benches, low rounded hills, and badlands. Rock outcrops occur. Sparsely vegetated with mat saltbush, bud sagebrush, galleta grass, and desert trumpet. Floodplains have alkaline soils that support greasewood, alkali sacaton, seepweed, and shadscale. Scattered, gravel-capped benches occur and protrude from the present surface because they are more resistant to erosion than the Caerus Operating, LLC | Garfield County, Colorado Wheeler Gulch Solar Project BIOLOGICAL RESOURCES REPORT 1670 Broadway, Suite 3400, Denver, CO 80202-4824 (303) 764-1520 hdrinc.com 2 surrounding shales. Soils are shallow and types range from clayey to silty (Chapman et al. 2006). The Escarpments are characterized by the following: Extensive, deeply-dissected, cliff-bench complexes. Local relief can be as great as 3,000 feet, and the region is prone to landslides. Includes major scarp slopes of the Book Cliffs and Roan Cliffs. Vegetation varies according to aspect and moisture availability, ranging from Douglas-fir forest on steep, north-facing slopes at higher elevations to desert and semidesert grassland or shrubland on lower, drier sites. (Chapman et al. 2006). The study area has a temperate climate with high temperatures averaging 70 degrees Fahrenheit (ºF) in July and low temperatures averaging 25ºF in January. The study area receives 17 inches of rain and 54 inches of snow per year on average (NOAA 2022). 2. Methods HDR biologists conducted a biological resources field survey of the study area on November 2, 2022. Wildlife habitat types and conditions were recorded during the field survey. Biologists walked or drove the entire project area and visually inspected the study area. Surveys for burrowing owl suitable nesting habitat were conducted within ¼-mile of the project area. A noxious weed survey was completed within the project area. An aquatic resources delineation was also completed within the project area during the November 2nd field survey. A desktop biological resource analysis was conducted prior to the field surveys to identify special status species that may occur in the study area. HDR biologists conducted a query of the U.S. Fish and Wildlife Service (USFWS) Information for Planning and Consultation (IPaC) database to identify ESA-listed species that may occur in the study area. Publicly available species range geospatial data from CPW was used to identify federal- and state-listed species that could occur in the study area. 3. Results 3.1. Threatened and Endangered Species Based on a search of the USFWS IPaC database (USFWS 2022a; Appendix B), there are 10 ESA-listed species with the potential to occur within or near the study area and one candidate species for listing under the ESA (Table 3-1). No designated or proposed critical habitat for any of the ESA-listed or candidate species occurs within the study area. There is Parachute beardtongue (Penstemon debilis) designated critical habitat approximately 1.7 miles south of the study area (USFWS 2020). There is also Colorado pikeminnow (Ptychocheilus lucius) designated critical habitat within the Colorado River approximately 3.1 miles southeast of the proposed study area (USFWS 2020). Parachute Creek creates an aquatic connection between the study area and the Colorado River where designated critical habitat occurs. Brief discussions of each species are provided below along with effect determinations. Because the Caerus Operating, LLC | Garfield County, Colorado Wheeler Gulch Solar Project BIOLOGICAL RESOURCES REPORT 1670 Broadway, Suite 3400, Denver, CO 80202-4824 (303) 764-1520 hdrinc.com 3 project would have no federal nexus, the following effect determinations are made for informational purposes only and not as part of Section 7 consultation with the USFWS. Table 3-1. ESA-listed species with potential to occur in or near the study area Common Name Scientific Name Listing Status Habitat and Range Description Suitable Habitat Determination Birds Mexican spotted owl Strix occidentalis lucida Threatened Old-growth forests of southern Utah, Colorado, Arizona, New Mexico, west Texas, and into the mountains of northern and central Mexico (Gutiérrez et al. 1995). Forests characterized by mature trees (18- inch diameter or greater), mainly Douglas- fir (Pseudotsuga menziesii) (Seamans and Gutiérrez 1995). No No effect Yellow-billed cuckoo Coccyzus americanus Threatened Wooded habitat with dense cover and water nearby, including woodlands with low, scrubby, vegetation, overgrown orchards, abandoned farmland, and dense thickets along streams and marshes (Beason 2012). No No effect Fish Bonytail Gila elegans Endangered Historically present in the Colorado River system. Stocking occurs within the Upper Colorado River Basin, but survival rates are low. No self-sustaining populations have been established within the upper Colorado River basin (USFWS 2019). No No effect* Colorado pikeminnow Ptychocheilus lucius Endangered Species occurs in the Colorado and Gunnison Rivers downstream of the project area. Habitat includes medium-to-large rivers. Young prefer small, quiet backwaters. Adults use various habitats, including deep turbid strongly flowing water, eddies, runs, flooded bottoms, or backwaters (USFWS 2022d). No No effect* Humpback chub Gila cypha Threatened Prefers deep, fast-moving, turbid waters often associated with large boulders and steep cliffs. Found in deep, canyon-bound portions of the Colorado River system. CPW-mapped Presence along Colorado River downstream of Parachute Creek inlet (CPW 2020a). No No effect* Razorback sucker Xyrauchen texanus Endangered Species associated with sand, mud, and rock substrate in areas with sparse aquatic vegetation, where temperatures are moderate to warm within the Colorado River system (USFWS 2018b). No No effect* Caerus Operating, LLC | Garfield County, Colorado Wheeler Gulch Solar Project BIOLOGICAL RESOURCES REPORT 1670 Broadway, Suite 3400, Denver, CO 80202-4824 (303) 764-1520 hdrinc.com 4 Table 3-1. ESA-listed species with potential to occur in or near the study area Common Name Scientific Name Listing Status Habitat and Range Description Suitable Habitat Determination Insects Monarch butterfly Danaus plexippus plexippus Candidate Monarchs occur throughout most of the contiguous U.S., requiring milkweed (Asclepias spp.) for reproduction which larval monarchs feed on. Adults feed on nectar from native plant species, including milkweed (NWF 2021). Milkweed observed scattered within riparian corridor No jeopardy Mammals Gray wolf Canis lupus Endangered Lone, dispersing gray wolves may be present throughout the state of Colorado. Considerations only needed if activities include a predator management program (USFWS 2022c). No No effect Plants Debeque phacelia Phacelia submutica Threatened Associated with steep slopes in clay badlands, mixed salt desert scrub, and Artemisia tridentata (big sagebrush) shrubland, within pinyon—juniper woodlands. Found on sparsely vegetated barren areas with total plant cover less than 10 percent (USFWS 2012). No No effect Parachute beardtongue Penstemon debilis Threatened Found on steep, constantly shifting shale cliffs with little vegetation characterized as ‘‘Rocky Mountain cliff and canyon’’. The plant community is unique because instead of being dominated by one or two common species as most plant communities are, it has a high diversity of uncommon species that also are oil shale endemics (USFWS 2012). No No effect Ute ladies’- tresses Spiranthes diluvialis Threatened Occurs in moist meadows associated with streams, floodplains, oxbows, lakeshores, and abandoned stream channels up to 7,000 feet in elevation. Also known from human modified wetlands such as irrigation canals, levees, irrigated meadows, and reservoirs. Found along the Front Range in Colorado as well as other regions in the interior Rocky Mountains (USFWS 1995). No No effect Table source: USFWS 2022a * Dependent on avoidance of Parachute Creek during construction 3.1.1. Mexican Spotted Owl Mexican spotted owls in Colorado prefer dense, mixed coniferous forests on steep slopes, often near canyons and rocky outcroppings between 6,500- and 9,500-feet elevation. Roosting and nesting habitat consist of mature and old-growth stands with complex structure including Caerus Operating, LLC | Garfield County, Colorado Wheeler Gulch Solar Project BIOLOGICAL RESOURCES REPORT 1670 Broadway, Suite 3400, Denver, CO 80202-4824 (303) 764-1520 hdrinc.com 5 uneven-aged and multi-stored trees, with an overall high canopy cover of greater than 70 percent (Wrigley et al. 2012). USFWS Mexican Spotted Owl Final Critical Habitat within Colorado is located along the Front Range from Castle Rock south to Pueblo (USFWS 2020). No suitable habitat exists within or in the vicinity of the study area. Therefore, the project will have no effect on Mexican spotted owl populations. 3.1.2. Yellow-billed Cuckoo Yellow-billed cuckoos prefer large tracts of structurally complex riparian habitats with tall trees and dense woody understory. Within Colorado, yellow-billed cuckoos are found in Fremont cottonwood (Populus fremontii) and narrow-leaf cottonwood (Populus angustifolia) riparian forests in western Colorado (Beason 2012). There is USFWS Yellow-billed Cuckoo Final Critical Habitat approximately 28 miles southwest of the study area along the Colorado River (USFWS 2020). No suitable habitat exists within or in the vicinity of the study area. Riparian habitat within the project area is lacking tall trees and is not present in large enough tracts. Therefore, the project will have no effect on yellow-billed cuckoo populations. 3.1.3. Bonytail Bonytail were historically present in the Colorado River system. Little is known about their natural preferred habitat and reproduction strategies because the only wild populations are supported by hatchery releases. Post-stocking survival in the wild may be as low as 2 – 5%. No self-sustaining populations have been established in the upper Colorado River basin (USFWS 2019). Designated critical habitat is present along the Colorado River on Colorado’s western border (USFWS 2020). Parachute Creek has a direct downstream connection to the Colorado River. However, the project is predicted to have no effect on bonytail as long as impacts to Parachute Creek are avoided. 3.1.4. Colorado Pikeminnow The Colorado pikeminnow was historically found throughout the warmwater portions of the Colorado River Basin from Wyoming to California (USFWS 2022d). They typically migrate long distances for spawning and make their way back to their home range where they are found in deep runs and pools. The larvae and juveniles require warm waters and low flow during development. Colorado pikeminnow declined as early as the 1930s due to the construction of dams and diversions. The wild population in the upper Colorado River Basin is made up of several hundred individuals, but has been declining in recent years (USFWS 2022d). Designated critical habitat is located along the Colorado River south of the study area. Parachute Creek has a direct downstream connection to the Colorado River (USFWS 2020). However, the project is predicted to have no effect on Colorado pikeminnow as long as impacts to Parachute Creek are avoided. 3.1.5. Humpback Chub Humpback chub have historically been found within warm waters of canyon bound rivers throughout portions of the Colorado, Green, and Yampa rivers. However, populations have declined due to the construction of several mainstem dams. There are currently four populations upstream and one population downstream of Lake Powell (USFWS 2018a). Designated critical habitat is located along the Colorado River on Colorado’s western border. Parachute Creek has Caerus Operating, LLC | Garfield County, Colorado Wheeler Gulch Solar Project BIOLOGICAL RESOURCES REPORT 1670 Broadway, Suite 3400, Denver, CO 80202-4824 (303) 764-1520 hdrinc.com 6 a direct downstream connection to the Colorado River (USFWS 2020). The project is predicted to have no effect on humpback chub as long as impacts to Parachute Creek are avoided. 3.1.6. Razorback Sucker The razorback sucker is found throughout warmwater portions of the Colorado River basin. This species has been increasing in numbers due to stocking and reintroduction programs. A lack of spawning habitat, which requires cobble or rocky substrate, was limiting wild reproduction, but the relatively long lifespan of the fish allowed the species to persist in areas where they were reintroduced. Changes to dam operations and floodplain management has increased wild recruitment in some areas (USFWS 2018b). Designated critical habitat is located along the Colorado River south of the study area (USFWS 2020). Water depletions in the upper Colorado River basin are a primary threat to the razorback sucker (USFWS 2018b). Parachute Creek has a direct downstream connection to the Colorado River. However, the project is predicted to have no effect on razorback sucker as long as impacts to Parachute Creek are avoided. 3.1.7. Monarch Butterfly Monarchs are found across North America wherever suitable habitat exists. There are two populations of monarchs, an eastern and western population, that are divided by the Rocky Mountains. The majority of individuals are part of the eastern population and breed across eastern and central North America and winter in Mexico. The smaller western population breeds in canyons and riparian areas across western North America into southern Canada and winters along the central and southern California coast. Monarchs migrate north through several generations with each generation living 2–5 weeks during which time they reproduce and lay eggs on milkweed plants that become the next generation. Monarchs require milkweed (Asclepias spp.) for reproduction because they feed on milkweed during the larval stage and visit milkweed flowers for nectar as an adult. Monarchs are not common in Colorado but can be found where suitable habitat and milkweed occurs (NWF 2021). The study area is within the eastern-most extent of the western population’s range (Xerces Society 2022) on the west side of the Rocky Mountains. Several dead milkweed plants were observed scattered throughout the riparian areas within the study area during the field survey, which was conducted outside of the growing season. However, impacts to monarch butterflies or milkweed are not expected as long as the wetlands identified in the Aquatic Resources Delineation Report where the milkweed plants were observed are avoided. Because monarch butterflies are not yet listed under the ESA, the effect determination would be made under conference and would begin with a jeopardy determination. Given that monarch butterflies are rare in this region and suitable habitat would not be affected, the project will not jeopardize the continued existence of monarch butterflies. We also make a provisional effect determination for this candidate species if it becomes listed in the future. Based on the above analysis, the project would have no effect on the monarch butterfly. Caerus Operating, LLC | Garfield County, Colorado Wheeler Gulch Solar Project BIOLOGICAL RESOURCES REPORT 1670 Broadway, Suite 3400, Denver, CO 80202-4824 (303) 764-1520 hdrinc.com 7 3.1.8. Gray Wolf Lone, dispersing gray wolves may be present throughout the state of Colorado. Considerations are needed only if activities include a predator management program. This project does not include a predator management program and is therefore expected to have no effect on the gray wolf. The State of Colorado is implementing a gray wolf reintroduction program. In the future, it is possible that re-introduced gray wolves may occur within or near the study area. However, operation of the solar facility would not adversely affect gray wolves and the above effect determination would not change. 3.1.9. Debeque phacelia Debeque phacelia is found on moderately steep slopes, benches, and ridge tops with exposures of alkaline clay soil derived from the Wasatch Formation in Mesa and Garfield Counties in Colorado. This plant species depends on the shrinking, swelling, and cracking process that these soils undergo with fluctuations in temperature (USFWS 2022e). Designated critical habitat is located near the town of Debeque, Colorado, approximately seven miles southwest of the study area (USFWS 2020). No suitable habitat exists within or in the vicinity of the study area. Therefore, the project will have no effect on Debeque phacelia populations. 3.1.10. Parachute beardtongue Parachute beardtongue is found on steep slopes of oil shale outcrops at 8,000 – 9,000 feet in elevation. They occur along the southern escarpment of the Roan Plateau above Parachute, Colorado. Within the Roan plateau, they only occupy approximately 92 acres on the Green River geologic formation (USFWS 2022f). Designated critical habitat is located approximately 1.7 miles southwest of the study area north of I-70 (USFWS 2020). No suitable habitat exists within or in the vicinity of the study area. Therefore, the project will have no effect on Parachute beardtongue populations. 3.1.11. Ute-ladies’ Tresses The Ute-ladies’ tresses is found in moist and wet meadows near lakes, streams, and springs, as well as near man-made wetlands such as canals, levees, and irrigated meadows. It has been found to occur up to 7,000 feet in elevation and has been found as low as 720 feet in Washington State (USFWS 2022b). This species is found in Colorado on the eastern slope of the Rocky Mountains as well as along riparian habitat in the northwest corner of the state. There is riparian habitat along Parachute Creek within the study area, but none that is suitable for Ute- ladies’ tresses. No wet meadows were observed, and most riparian areas are densely covered in coyote willow (Salix exigua), common reed (Phragmites australis), or cattails (Typha spp.). The project will have no effect on Ute-ladies’ Tresses. 3.2. Other Federally Listed Species 3.2.1. Migratory Bird Treaty Act The MBTA (16 U.S.C. 703–712) prohibits the incidental and intentional (Vinson & Elkins 2021) take of protected migratory bird species without prior authorization. Almost all birds, with few exceptions, are protected by the MBTA. As it relates to construction and maintenance of solar facilities, any ground-disturbing activity, including vegetation removal, has a potential to disturb Caerus Operating, LLC | Garfield County, Colorado Wheeler Gulch Solar Project BIOLOGICAL RESOURCES REPORT 1670 Broadway, Suite 3400, Denver, CO 80202-4824 (303) 764-1520 hdrinc.com 8 or destroy nests and harm eggs or young or adult birds. In addition, noise and human presence can disturb nesting birds, causing them to temporarily or permanently abandon their nest site. In general, passerines (songbirds) and other small birds should be protected from direct impacts to the nest but are tolerant of indirect disturbance from activities. However, birds of prey, or raptors, are generally less tolerant of disturbance. CPW has published recommended seasonal and spatial nest avoidance measures for raptor species (CPW 2020b). The closest Important Bird Area (IBA) is The Grand Valley Riparian Corridor, which is approximately 22 miles southwest of the study area. The Grand Valley Riparian Corridor has provided lowland riparian habitat to nearly 300 bird species over the last 15 years (NAS 2022). There are no IBAs close enough to the study area to influence avian activity in or near the project. During the field survey and raptor nest survey, three unoccupied raptor nests were identified along Parachute Creek (Appendix A, Figure 3). No raptors were observed during the field survey. Suitable raptor nesting habitat within the study area consists of trees that are large enough to support a large stick nest or provide cavities as well as cliffs or rock outcrops. The mature cottonwood trees associated with the riparian habitat along Parachute Creek provides suitable nesting habitat for raptors. The cliffs on the north side of County Road 215 provide suitable nesting habitat for raptors such as golden eagles that often utilize cliff outcrops to build their nests. An approximately 18-acre active white-tailed prairie dog colony was identified during the field survey within the project area (Appendix A, Figure 3). The colony is on the east side of the project area, primarily along the south side of County Road 215. The density of the burrows decreased in the southeast corner of the project area. The study area is frequented by numerous other bird species protected under the MBTA. During the field survey, avian species incidentally observed included mountain bluebird (Sialia currucoides), common raven (Corvus corax), and mallard (Anas platyrhynchos). No nests were observed at the time of the field surveys, but the surveys were conducted outside of the breeding season. Additionally, wild turkey (Meleagris gallopavo) tracks were observed near the riparian area on the southwest side of the project. 3.2.2. Bald and Golden Eagle Protection Act In addition to protections under the MBTA, bald eagles (Haliaeetus leucocephalus) and golden eagles (Aquila chrysaetos) are also protected under the Bald and Golden Eagle Protection Act (16 U.S.C. 668-668c; BGEPA). Bald eagle roost sites and bald and golden eagle nest sites are at risk of disturbance from construction activities. There is a CPW-mapped bald eagle nest located along Parachute Creek approximately 1.5 miles northwest of the project. There are mature cottonwood trees along Parachute Creek that could potentially provide nesting and roosting opportunities for bald eagles within the study area. The nest was last surveyed by CPW in 2018 and was active at that time. The closest known golden eagle nest is approximately 2 miles north of the project located on a cliff face (CPW 2019). Caerus Operating, LLC | Garfield County, Colorado Wheeler Gulch Solar Project BIOLOGICAL RESOURCES REPORT 1670 Broadway, Suite 3400, Denver, CO 80202-4824 (303) 764-1520 hdrinc.com 9 The study area is not within any CPW-designated bald eagle foraging, concentration, or roosting areas (CPW 2020a). The study area is within bald eagle winter range. There are CPW- designated bald eagle winter forage areas along the Colorado River, which Parachute Creek flows into approximately 3.3 miles southeast of the study area (CPW 2020a). Neither bald nor golden eagles were observed within or near the study area during the field survey. 3.3. State-Listed Species HDR biologists used publicly available CPW species GIS data (CPW 2020a) along with other literature to determine the potential occurrence of each state-listed species within or near the study area. Of the 74 wildlife species currently listed as state endangered, state threatened, or state special concern, five species were found to have potentially suitable habitat within or near the study area (Table 3-3). One species, the burrowing owl, is listed as state threatened. The remaining four species are listed as state special concern. None of these species were observed in the study area during the field survey. ESA-listed species are discussed in Section 3.1 and are not included here. Fish species that utilize the Colorado River, which has a direct downstream connection to Parachute Creek, are included. Avoidance of Parachute Creek during construction would prevent potential impacts to the fish species that utilize the downstream Colorado River. Table 3-3. State-listed species with the potential to occur in or near the study area Common Name Scientific Name Listing Status Habitat and Range Description Suitable Habitat Amphibians Northern Leopard Frog Rana pipiens Special Concern Found in wet meadows and the banks and shallows of marshes, ponds, lakes, reservoirs, streams, and irrigation ditches (CPW 2022). Yes Birds Bald Eagle Haliaeetus leucocephalus Special Concern Found along the Colorado River during both summer and winter. Frequently nest in large cottonwood trees. Communally roost in large trees during the winter (CPW 2022). Yes Burrowing Owl Athene cunicularia State Threatened Found in dry, open areas with short grasses and no trees. They nest and live in underground burrows created by prairie dogs, ground squirrels and badgers (CPW 2022). Yes American Peregrine Falcon Falco peregrinus anatum Special Concern Inhabit open spaces associated with high cliffs and bluffs overlooking rivers. Can be found from the Front Range to Colorado’s western border (CPW 2022). Yes Fish Colorado Roundtail Chub Gila robusta Special Concern Adults prefer large, perennial streams with deep pools and cover as well as riffles, runs, and eddies. Range historically included the Colorado River and its tributaries. Current overall range is similar, but only 45% occupancy of historic range (NatureServe 2022). No Caerus Operating, LLC | Garfield County, Colorado Wheeler Gulch Solar Project BIOLOGICAL RESOURCES REPORT 1670 Broadway, Suite 3400, Denver, CO 80202-4824 (303) 764-1520 hdrinc.com 10 Table 3-3. State-listed species with the potential to occur in or near the study area Common Name Scientific Name Listing Status Habitat and Range Description Suitable Habitat Mountain Sucker Catostomus playtrhynchus Special Concern Prefers clear, cold creels and small to medium rivers. Occurs through much of the western United States. In Colorado, found in the Green River drainage as well as the headwaters of the Yampa, Colorado, and Green Rivers. Rare within the mainstem Colorado River drainage outside of the Duchesne River drainage (USDA 2006). No Mammals Townsend’s Big-Eared Bat Corynorhinus townsendii pallescens Special Concern Found in mines, caves, and large rock cavities to elevations above 9,500 feet (CPW 2022). No Reptiles Midget Faded Rattlesnake Crotalus viridis concolor Special Concern Found in Garfield County in a wide variety of terrestrial habitats except for perennially wet areas and high mountains. Shelters in crevices, mammal burrows, and brushy vegetation. Hibernates in rodent burrows or in crevices in rock outcrops (CPW 2022). Yes Source: CPW 2020a 3.4. Big Game Species HDR biologists used publicly available CPW species spatial data (CPW 2020a) along with other literature to determine the potential occurrence of big game species within or near the study area. The study area is within elk overall, winter, and severe winter ranges as well as an elk winter concentration area (Appendix A, Figure 4). The study area is also within mule deer overall, winter, and severe winter ranges as well as a mule deer concentration, resident population, and winter concentration areas (Appendix A, Figure 5). County Road 215 is a CPW- mapped mule deer and elk highway crossing, and there is a mule deer migration pattern crossing the project from southwest to northeast (Appendix A, Figures 4 and 5). No big game species were observed during the field survey, but evidence of both mule deer and elk was observed within the central areas of the project. Tracks indicated that big game likely utilizes the area to access the water sources and cover associated with Parachute Creek. There were also tracks observed throughout the open water feature on the east-central side of the project. This water feature was dry during the field survey and is the remnants of a historically larger retention pond. More information about this open water feature can be found in the Aquatic Resources Delineation Report. This project has the potential to create a barrier to big game movement and to create additional hazards for big game considering the surrounding industrial development along the valley and the Parachute Creek riparian corridor. Exclusionary fencing has the potential to limit movement, create entanglement risks, and introduce other hazards for big game. Potential mitigation measures recommended by CPW are discussed in Section 4.5 and 5. Caerus Operating, LLC | Garfield County, Colorado Wheeler Gulch Solar Project BIOLOGICAL RESOURCES REPORT 1670 Broadway, Suite 3400, Denver, CO 80202-4824 (303) 764-1520 hdrinc.com 11 3.5 Noxious Weeds HDR biologists completed a noxious weed survey within the project area during the November 2 field survey. This survey took place outside of the growing season, but the remnants of several species of noxious weeds were still visible. Plant species listed as noxious by the Colorado Department of Agriculture (CDA) are included in Table 3-5 with their rank. Table 3-5. Noxious weed species identified within the project area Common Name Scientific Name List Ranking General Area Observed Salt Cedar Tamarix chinensis B Surrounding open water feature on east-central side of project area; details in Aquatic Resources Delineation Report Canada Thistle Cirsium arvense B Riparian along Parachute Creek Common Burdock Arctium minus C Southeastern riparian area along Parachute Creek Downy Brome Bromus tectorum C Throughout upland areas Common Reed Phragmites australis Watch List Riparian along Parachute Creek Source: CDA 2022 4. Impact Evaluation and Recommendations 4.1. Threatened and Endangered Species As discussed in Section 3.1, the project is not expected to result in any adverse effects on threatened, endangered, or candidate species. Avoidance of Parachute Creek during construction is recommended to avoid potential impacts to the threatened or endangered fish species that inhabit the Colorado River. Sediment discharge to Parachute Creek should be avoided through implementation of stormwater best management practices to prevent impacts to downstream waterways. 4.2. Migratory Birds If construction will include the removal of vegetation between April 1 and August 31, then nesting songbird surveys are recommended within the construction footprint fewer than seven days prior to construction start. Three unoccupied raptor nests were observed approximately 0.1 mile southwest of the project area during the field survey. No raptors were observed in the area. Should construction occur February 15 and August 31, additional raptor nest surveys may be recommended to confirm the status of these nests and confirm no new nests have been built. A white-tailed prairie dog colony was observed within the project area. Burrowing owls commonly use prairie dog burrows during the breeding season. If construction is planned to occur between March 15 and August 31, burrowing owl surveys are recommended prior to disturbance of the area. CPW recommends a ¼ mile buffer around burrowing owl nest sites for large scale disturbances (CPW 2020b). Caerus Operating, LLC | Garfield County, Colorado Wheeler Gulch Solar Project BIOLOGICAL RESOURCES REPORT 1670 Broadway, Suite 3400, Denver, CO 80202-4824 (303) 764-1520 hdrinc.com 12 4.3. Bald and Golden Eagles No impacts to bald or golden eagles are anticipated as a result of the project. The closest bald or golden eagle nest is a bald eagle nest approximately 1.5 miles north of the of the project, according to the CPW raptor nest database (CPW 2019). No bald or golden eagles were observed within or near the study area during the field survey. Bald eagle nest surveys are recommended if construction will occur between December 1 and July 31. Bald eagle nest and roost surveys are recommended prior to construction within the study area due to the mature cottonwood trees along Parachute Creek. Bald eagle night roost surveys are recommended if construction will occur between November 15 and March 15 (CPW 2020b). 4.4. State-Listed Species Of the five state-listed species with potentially suitable habitat within or near the study area, none were observed during the field survey. Construction that occurs between November 15 and August 31 has the potential to impact peregrine falcons and other state-listed birds during nesting or roosting (CPW 2020b). Surveys are recommended prior to construction to confirm that no new nests or roosts have been constructed or are being utilized within the study area. Northern leopard frogs are likely to be found within or near the riparian habitat associated with Parachute Creek. No impacts to northern leopard frogs are expected if this riparian habitat is avoided. Midget faded rattlesnakes could potentially use the prairie dog burrows on the eastern side of the project to hibernate. Education on species identification and conflict avoidance for workers on site would benefit this species and improve the safety of workers. 4.5. Big Game Species As discussed in Section 3.4, this project has the potential to create a barrier that limits the movement of big game in the area. It is recommended that the layout of exclusionary fencing leave a path for big game to travel in a northeast-southwest direction between the solar facility and neighboring facilities. Other mitigation measures to prevent impacts to big game are discussed below in Section 5. Big game species including mule deer and elk may be temporarily disturbed or displaced by construction activity. Collisions or other direct effects are unlikely as most individuals will likely avoid the area during active construction. Slow speeds and situational awareness of workers are recommended to further reduce the likelihood of collisions or other direct effects. 4.6 Noxious Weeds Although completed outside of the growing season, the noxious weed survey identified five species listed as noxious by the CDA (CDA 2022). None of the species identified are listed for immediate elimination (ie., List A species). Construction activity has the potential to increase the size and density of noxious weed infestations through soil disturbance and the unintended spread of seeds. Caerus Operating, LLC | Garfield County, Colorado Wheeler Gulch Solar Project BIOLOGICAL RESOURCES REPORT 1670 Broadway, Suite 3400, Denver, CO 80202-4824 (303) 764-1520 hdrinc.com 13 The following general actions are recommended (as appropriate) to minimize the spread of noxious weeds: • All construction equipment will remain in designated work areas. • All equipment will be thoroughly cleaned before entering and exiting the project area. • The area of ground disturbance will be kept to the minimum necessary. • Use of imported topsoil will be minimized during construction. If importing is necessary, certified weed-fee soil will be used. • All mulches and erosion bales used the site will be certified weed-free. • All disturbed areas will be seeded after construction. Seeding will consist of native grasses and forbs and should be phased throughout construction (as appropriate) to minimize bare ground. • All seed mixes, soil, and other plant material used for revegetation will be free of noxious weed seeds, roots, and other propagules. 5. CPW Recommendations HDR met with CPW’s Northwest Region Energy Liaison, Taylor Elm, on November 29, 2022, to discuss potential impacts to wildlife associated with this project. Mitigation measures discussed include: • The project has the potential to create a barrier to big game movement and to create additional hazards for big game considering the surrounding industrial development along the valley and the Parachute Creek riparian corridor. Recommended measures to prevent this impact include: o Choose an 8’ woven wire fencing design instead of a 6’ design with a barbed top wire to prevent entanglement with exclusionary fencing. o Avoid potential pinch points along exclusionary fencing that might trap big game or funnel them towards County Road 215. Consider where big game will cross County Road 215 in the context of potential vehicle strikes. o Provide a path between the riparian corridor south of the Project, County Road 215, and the canyon to the north of the Project for big game to travel without the need to navigate fence crossings. Incorporate this consideration into the initial exclusionary fencing layout. o Avoid construction during the winter months if possible to allow for big game habitat use. o Ensure that gates remain closed when not in use to prevent big game from entering the facility. • The project is within ½ mile of raptor nesting habitat and there is a prairie dog colony within the project area, which provides potential nesting habitat for burrowing owls. Considerations discussed regarding raptors include: o Complete raptor nest surveys, including burrowing owl surveys, depending on when construction will take place. Caerus Operating, LLC | Garfield County, Colorado Wheeler Gulch Solar Project BIOLOGICAL RESOURCES REPORT 1670 Broadway, Suite 3400, Denver, CO 80202-4824 (303) 764-1520 hdrinc.com 14 o If the construction of additional transmission lines or substation is required, ensure that designs incorporate Avian Power Line Interaction Committee (APLIC) guidelines to reduce collision and electrocution risks to raptors, birds, and other wildlife. • The project is within a wild turkey concentration area. Avoidance of riparian habitat is sufficient to prevent impacts to wild turkeys. • Incorporating small gaps at the bottom of exclusionary fencing would be beneficial to small mammals moving through the area and using habitat within the facility. 6. References Beason 2012 Beason, J. 2012. Yellow-billed Cuckoos in Western Colorado in Colorado Birds. Available from: <https://birdconservancy.org/wp- content/uploads/2018/10/CO_birds_2012v46_beason.pdf#page=17>. Accessed on November 23, 2022. CDA 2022 Colorado Department of Agriculture (CDA). Noxious Weed Species ID. Available from:<https://ag.colorado.gov/conservation/noxious- weeds/species-id>. Accessed December 16, 2022. Chapman et al. 2006 Chapman, S.S., Griffith, G.E., Omernik, J.M., Price, A.B., Freeouf, J., and Schrupp, D.L. 2006. Ecoregions of Colorado (color poster with map, descriptive text, summary tables, and photographs): Reston, Virginia, U.S. Geological Survey (map scale 1:1,200,000). Available online: <https://www.epa.gov/eco-research/ecoregion-download-files-state- region-8>. Accessed September 1, 2021. CPW 2019 Colorado Parks and Wildlife. 2019. CPW Raptor Nest Spatial Dataset for Colorado. Data obtained with use-permission from CPW in January 2019. CPW 2020a Colorado Parks and Wildlife. 2020. CPW Species Data, ArcGIS Online web service. Updated December 8, 2020. Available via ArcGIS Online servers. CPW 2020b Colorado Parks and Wildlife. 2020. Recommended Buffer Zones and Seasonal Restrictions for Colorado Raptors (2020). Available online: <https://cpw.state.co.us/Documents/WildlifeSpecies/LivingWithWildlife/Ra ptor-Buffer-Guidelines.pdf>. Accessed October 19, 2021. CPW 2022 Colorado Parks and Wildlife. 2021. Threatened & Endangered Species Profiles. Available online: <http://cpw.state.co.us/learn/Pages/SpeciesProfiles.aspx>. Accessed November 23, 2022. Gutiérrez et al. 1995 Gutiérrez, R. J., A. B. Franklin and W. S. Lahaye. 1995. Spotted Owl (Strix occidentalis), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Birds of North America Online. NAS 2022 National Audubon Society (NAS). 2022. Grand Valley Riparian Corridor. Available from: <https://www.audubon.org/important-bird-areas/grand- valley-riparian-corridor>. Accessed on November 18, 2022. Caerus Operating, LLC | Garfield County, Colorado Wheeler Gulch Solar Project BIOLOGICAL RESOURCES REPORT 1670 Broadway, Suite 3400, Denver, CO 80202-4824 (303) 764-1520 hdrinc.com 15 NatureServe 2022 Nature Serve Explorer. 2022. Roundtail Chub. Available from: <https://explorer.natureserve.org/Taxon/ELEMENT_GLOBAL.2.791391/ Gila_robusta>. Accessed on: November 23, 2022. NLCD 2019 National Land Cover Database (NLCD). 2019. Multi-Resolution Land Characteristics Consortium (MRLC) NLCD Viewer. Available from: <https://www.mrlc.gov/viewer/>. Accessed on: April 22, 2022. NOAA 2022 National Oceanic & Atmospheric Administration (NOAA). 2022. Summary of Monthly Normals. Monument, CO. <https://www.ncei.noaa.gov/access/us-climate- normals/#dataset=normals- annualseasonal&timeframe=30&location=CO&station=USC00055734>. Accessed April 21, 2022. NWF 2021 NWF (National Wildlife Federation). 2021. Monarch Butterfly. Available from: <https://www.nwf.org/Educational-Resources/Wildlife- Guide/Invertebrates/Monarch-Butterfly>. Accessed on: September 3, 2021. Seamans and Gutiérrez 1995 Seamans, M.E. and R.J. Gutierrez. 1995. Breeding habitat of the Mexican Spotted Owl in the Tularosa Mountains, New Mexico. The Condor 97:944-952. USDA 2006 USDA. 2006. Mountain Sucker (Catostomus platyrhynchus): A Technical Conservation Assessment. Available from: <https://www.fs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb5206796. pdf>. Accessed on: November 23, 2022. USFWS 1995 USFWS. 1995. Ute ladies’-tresses (Spiranthes diluvialis) recovery plan. U.S. Fish and Wildlife Service, Denver, Colorado. 46pp. USFWS 2012 USFWS. 2012. Endangered and Threatened Wildlife and Plants; Designation of Critical Habitat for Ipomopsis polyantha (Pagosa skyrocket), Penstemon debilis (Parachute beardtongue), and Phacelia submutica (DeBeque phacelia). Available from <https://www.govinfo.gov/content/pkg/FR-2012-08-13/pdf/2012- 18833.pdf#page=1>. Accessed on November, 23, 2022. USFWS 2018a USFWS. 2018. Species Status Assessment for the Humpback Chub (Gila cypha). Available from:<https://ecos.fws.gov/ServCat/DownloadFile/196747>. Accessed on November 23, 2022. USFWS 2018b USFWS. 2018. 5-Year Review – Razorback Sucker (Xyrauchen texanus). Available from: <https://ecos.fws.gov/docs/tess/species_nonpublish/2605.pdf>. Accessed on November 23, 2022. USFWS 2019 USFWS. 2019. 5-Year Review Short Form – Bonytail (Gila elegans). Available from: <https://ecos.fws.gov/docs/tess/species_nonpublish/2734.pdf>. Accessed on November 23, 2022. USFWS 2020 USFWS. 2020. FWS. Critical Habitat Vector Digital Data Set (Polygon). Available online: <http://ecos.fws.gov/docs/crithab/crithab_all/crithab_all_layers.zip>. Accessed September 2, 2021. Caerus Operating, LLC | Garfield County, Colorado Wheeler Gulch Solar Project BIOLOGICAL RESOURCES REPORT 1670 Broadway, Suite 3400, Denver, CO 80202-4824 (303) 764-1520 hdrinc.com 16 USFWS 2022a USFWS. 2022. Threatened, endangered, candidate, and proposed species. IpaC (Information, Planning, and Conservation System); Available online: <https://ecos.fws.gov/ipac/>. Accessed November 18, 2022. USFWS 2022b USFWS. 2022. Environmental Conservation Online System (ECOS) – Ute ladies’ tresses (Spiranthes diluvialis). Available online: <https://ecos.fws.gov/ecp/species/2159>. Accessed November 18, 2022. USFWS 2022c USFWS. 2022. Environmental Conservation Online System (ECOS) – Species Profile: Gray Wolf (Canus lupus). Available online: <https://ecos.fws.gov/ecp/species/4488>. Accessed November 18, 2022. USFWS 2022d USFWS. 2022. Species Status Assessment Report for the Colorado Pikeminnow (Ptychocheilus lucius). Available from: <https://ecos.fws.gov/ServCat/DownloadFile/219586>. Accessed on November 23, 2022. USFWS 2022e USFWS. 2022. Environmental Conservation Online System (ECOS) – Species Profile: DeBeque phacelia (Phacelia submutica). Available online: <https://ecos.fws.gov/ecp/species/4639>. Accessed November 23, 2022. USFWS 2022f USFWS. 2022. Environmental Conservation Online System (ECOS) – Species Profile: Parachute beardtongue (Penstemon debilis). Available online: <https://ecos.fws.gov/ecp/species/7099>. Accessed November 23, 2022. Vinson & Elkins 2021 Vinson & Elkins. 2021. Biden administration looks to recriminalize accidental bird deaths in traditional and renewable energy sectors. JDSupra Online. Available from: <https://www.jdsupra.com/legalnews/biden-administration-looks-to- 2642339/>. Accessed 26 May 2021. Wrigley et al. 2012 Wrigley, M.J., M. White, B. Elliott, M. Comer, R.E. Torretta, P. Gaines, S Olson, K. Meyer, M. Painter, J. Windorski, F. Quesada, and M. Welker. 2012 Threatened, endangered, and Forest Service Sensitive Species on the Pike and San Isabel National Forests (updated June 2012). Unpubl. Rpt. U.S. Department of Agriculture, Forest Service. Pike and San Isabel National Forests and Comanche and Cimarron National Grasslands. Salida, Colorado. Xerces Society 2022 Xerces Society for Invertebrate Conservation. 2022. Timing Management in Monarch Breeding Habitat. Available from: <https://monarchjointventure.org/images/uploads/documents/18_010_timi ng_management_in_western_monarch_habitat_xercessoc.pdf >. Accessed on December 6, 2022. Caerus Operating, LLC | Garfield County, Colorado Wheeler Gulch Solar Project BIOLOGICAL RESOURCES REPORT 1670 Broadway, Suite 3400, Denver, CO 80202-4824 (303) 764-1520 hdrinc.com A Figures Garfield Rio Blanco Mesa ¯Biological Resources Report (Figure 1) Wheeler Gulch Solar Project Garfield County, CO 0 0.20.1 Miles Colorado River Parachute Parachute Creek Project Area 70 215 P a r a c h u t e C r e e k NHD Stream/ River Biological Resources Report (Figure 2) Wheeler Gulch Solar Project Garfield County, CO 0 0.30.15 Miles Dewitz, J., and U.S. Geological Survey, 2021, National Land Cover Database (NLCD) 2019 Products (ver. 2.0, June 2021): U.S. Geological Survey data release, https://doi.org/10.5066/P9KZCM54. Emergent Herbaceous Wetlands Woody Wetlands Cultivated Crops Pasture/ Hay Grasslands/ Herbaceous Shrub/ Scrub Evergreen Forest Barren Land (Rock/ Sand/ Clay) Developed, High Intensity Developed, Medium Intensity Developed, Low Intensity Developed, Open Space Open Water Land Cover Study Area Project Area 215 Pa rac h u te C re e k R d Parachute C reekRd ¯ Biological Resources Report (Figure 3) Wheeler Gulch Solar Project Garfield County, CO 0 0.50.25 Miles Project Area Study Area Prairie Dog ColonyRaptor Nests 215 Parachu t e C r e e k NHD Stream/ River Parac h ute C re e k R d Parachute C reek R d ¯ Biological Resources Report (Figure 4) Wheeler Gulch Solar Project Garfield County, CO 0 0.50.25 Miles Project Area Study Area 215 Parachu t e C r e e k NHD Stream/ River Winter Range Winter Concentration Area Severe Winter Range Highway Crossings CPW Elk Ranges Parac h ute C re e k R d Parachute C reek R d ¯ Biological Resources Report (Figure 5) Wheeler Gulch Solar Project Garfield County, CO 0 0.50.25 Miles 215 Parachu t e C r e e k Project Area Study Area NHD Stream/ River Winter Range Winter Concentration Area Severe Winter Range Highway Crossings CPW Mule Deer Ranges Resident Population Area Concentration Area Migration Patterns Caerus Operating, LLC | Garfield County, Colorado Wheeler Gulch Solar Project BIOLOGICAL RESOURCES REPORT 1670 Broadway, Suite 3400, Denver, CO 80202-4824 (303) 764-1520 hdrinc.com B IPaC Report IPaC resource list This report is an automatically generated list of species and other resources such as critical habitat (collectively referred to as trust resources) under the U.S. Fish and Wildlife Service's (USFWS) jurisdiction that are known or expected to be on or near the project area referenced below. The list may also include trust resources that occur outside of the project area, but that could potentially be directly or indirectly a ected by activities in the project area. However, determining the likelihood and extent of e ects a project may have on trust resources typically requires gathering additional site-speci c (e.g., vegetation/species surveys) and project-speci c (e.g., magnitude and timing of proposed activities) information. Below is a summary of the project information you provided and contact information for the USFWS o ce(s) with jurisdiction in the de ned project area. Please read the introduction to each section that follows (Endangered Species, Migratory Birds, USFWS Facilities, and NWI Wetlands) for additional information applicable to the trust resources addressed in that section. Location Gar eld County, Colorado Local o ce Western Colorado Ecological Services Field O ce (970) 628-7180 (970) 245-6933 U.S. Fish & Wildlife ServiceIPaC 445 West Gunnison Avenue, Suite 240 Grand Junction, CO 81501-5711 Endangered species This resource list is for informational purposes only and does not constitute an analysis of project level impacts. The primary information used to generate this list is the known or expected range of each species. Additional areas of in uence (AOI) for species are also considered. An AOI includes areas outside of the species range if the species could be indirectly a ected by activities in that area (e.g., placing a dam upstream of a sh population even if that sh does not occur at the dam site, may indirectly impact the species by reducing or eliminating water ow downstream). Because species can move, and site conditions can change, the species on this list are not guaranteed to be found on or near the project area. To fully determine any potential e ects to species, additional site-speci c and project-speci c information is often required. Section 7 of the Endangered Species Act requires Federal agencies to "request of the Secretary information whether any species which is listed or proposed to be listed may be present in the area of such proposed action" for any project that is conducted, permitted, funded, or licensed by any Federal agency. A letter from the local o ce and a species list which ful lls this requirement can only be obtained by requesting an o cial species list from either the Regulatory Review section in IPaC (see directions below) or from the local eld o ce directly. For project evaluations that require USFWS concurrence/review, please return to the IPaC website and request an o cial species list by doing the following: 1. Draw the project location and click CONTINUE. 2. Click DEFINE PROJECT. 3. Log in (if directed to do so). 4. Provide a name and description for your project. 5. Click REQUEST SPECIES LIST. Listed species and their critical habitats are managed by the Ecological Services Program of the U.S. Fish and Wildlife Service (USFWS) and the sheries division of the National Oceanic and Atmospheric Administration (NOAA Fisheries ). Species and critical habitats under the sole responsibility of NOAA Fisheries are not shown on this list. Please contact NOAA Fisheries for species under their jurisdiction. 1. Species listed under the Endangered Species Act are threatened or endangered; IPaC also shows species that are candidates, or proposed, for listing. See the listing status page for more information. IPaC only shows species that are regulated by USFWS (see FAQ). 1 2 2. NOAA Fisheries, also known as the National Marine Fisheries Service (NMFS), is an o ce of the National Oceanic and Atmospheric Administration within the Department of Commerce. The following species are potentially a ected by activities in this location: Mammals Birds Fishes NAME STATUS Gray Wolf Canis lupus This species only needs to be considered if the following condition applies: Lone, dispersing gray wolves may be present throughout the state of Colorado. If your activity includes a predator management program, please consider this species in your environmental review. There is nal critical habitat for this species. https://ecos.fws.gov/ecp/species/4488 Endangered NAME STATUS Mexican Spotted Owl Strix occidentalis lucida Wherever found There is nal critical habitat for this species.Your location does not overlap the critical habitat. https://ecos.fws.gov/ecp/species/8196 Threatened Yellow-billed Cuckoo Coccyzus americanus There is nal critical habitat for this species.Your location does not overlap the critical habitat. https://ecos.fws.gov/ecp/species/3911 Threatened NAME STATUS Bonytail Gila elegans Wherever found There is nal critical habitat for this species.Your location does not overlap the critical habitat. https://ecos.fws.gov/ecp/species/1377 Endangered Insects Flowering Plants Colorado Pikeminnow Ptychocheilus lucius There is nal critical habitat for this species.Your location does not overlap the critical habitat. https://ecos.fws.gov/ecp/species/3531 Endangered Humpback Chub Gila cypha Wherever found There is nal critical habitat for this species.Your location does not overlap the critical habitat. https://ecos.fws.gov/ecp/species/3930 Threatened Razorback Sucker Xyrauchen texanus Wherever found This species only needs to be considered if the following condition applies: Water depletions in the upper Colorado River basin adversely a ect this species and its critical habitat. E ects of water depletions must be considered even outside of occupied range. There is nal critical habitat for this species.Your location does not overlap the critical habitat. https://ecos.fws.gov/ecp/species/530 Endangered NAME STATUS Monarch Butter y Danaus plexippus Wherever found No critical habitat has been designated for this species. https://ecos.fws.gov/ecp/species/9743 Candidate NAME STATUS Debeque Phacelia Phacelia submutica Wherever found There is nal critical habitat for this species.Your location does not overlap the critical habitat. https://ecos.fws.gov/ecp/species/4639 Threatened Critical habitats Potential e ects to critical habitat(s) in this location must be analyzed along with the endangered species themselves. There are no critical habitats at this location. Migratory birds Parachute Beardtongue Penstemon debilis Wherever found There is nal critical habitat for this species.Your location does not overlap the critical habitat. https://ecos.fws.gov/ecp/species/7099 Threatened Ute Ladies'-tresses Spiranthes diluvialis Wherever found No critical habitat has been designated for this species. https://ecos.fws.gov/ecp/species/2159 Threatened Certain birds are protected under the Migratory Bird Treaty Act and the Bald and Golden Eagle Protection Act . Any person or organization who plans or conducts activities that may result in impacts to migratory birds, eagles, and their habitats should follow appropriate regulations and consider implementing appropriate conservation measures, as described below. 1. The Migratory Birds Treaty Act of 1918. 2. The Bald and Golden Eagle Protection Act of 1940. Additional information can be found using the following links: Birds of Conservation Concern https://www.fws.gov/program/migratory-birds/species Measures for avoiding and minimizing impacts to birds https://www.fws.gov/library/collections/avoiding-and-minimizing-incidental-take- migratory-birds Nationwide conservation measures for birds https://www.fws.gov/sites/default/ les/documents/nationwide-standard-conservation- measures.pdf 1 2 The birds listed below are birds of particular concern either because they occur on the USFWS Birds of Conservation Concern (BCC) list or warrant special attention in your project location. To learn more about the levels of concern for birds on your list and how this list is generated, see the FAQ below. This is not a list of every bird you may nd in this location, nor a guarantee that every bird on this list will be found in your project area. To see exact locations of where birders and the general public have sighted birds in and around your project area, visit the E-bird data mapping tool (Tip: enter your location, desired date range and a species on your list). For projects that occur o the Atlantic Coast, additional maps and models detailing the relative occurrence and abundance of bird species on your list are available. Links to additional information about Atlantic Coast birds, and other important information about your migratory bird list, including how to properly interpret and use your migratory bird report, can be found below. For guidance on when to schedule activities or implement avoidance and minimization measures to reduce impacts to migratory birds on your list, click on the PROBABILITY OF PRESENCE SUMMARY at the top of your list to see when these birds are most likely to be present and breeding in your project area. BREEDING SEASON Probability of Presence Summary The graphs below provide our best understanding of when birds of concern are most likely to be present in your project area. This information can be used to tailor and schedule your project activities to avoid or minimize impacts to birds. Please make sure you read and NAME Bald Eagle Haliaeetus leucocephalus This is not a Bird of Conservation Concern (BCC) in this area, but warrants attention because of the Eagle Act or for potential susceptibilities in o shore areas from certain types of development or activities. Breeds Dec 1 to Aug 31 Black Rosy- nch Leucosticte atrata This is a Bird of Conservation Concern (BCC) throughout its range in the continental USA and Alaska. https://ecos.fws.gov/ecp/species/9460 Breeds Jun 15 to Aug 31 Evening Grosbeak Coccothraustes vespertinus This is a Bird of Conservation Concern (BCC) throughout its range in the continental USA and Alaska. Breeds May 15 to Aug 10 Western Grebe aechmophorus occidentalis This is a Bird of Conservation Concern (BCC) throughout its range in the continental USA and Alaska. https://ecos.fws.gov/ecp/species/6743 Breeds Jun 1 to Aug 31 understand the FAQ "Proper Interpretation and Use of Your Migratory Bird Report" before using or attempting to interpret this report. Probability of Presence () Each green bar represents the bird's relative probability of presence in the 10km grid cell(s) your project overlaps during a particular week of the year. (A year is represented as 12 4- week months.) A taller bar indicates a higher probability of species presence. The survey e ort (see below) can be used to establish a level of con dence in the presence score. One can have higher con dence in the presence score if the corresponding survey e ort is also high. How is the probability of presence score calculated? The calculation is done in three steps: 1. The probability of presence for each week is calculated as the number of survey events in the week where the species was detected divided by the total number of survey events for that week. For example, if in week 12 there were 20 survey events and the Spotted Towhee was found in 5 of them, the probability of presence of the Spotted Towhee in week 12 is 0.25. 2. To properly present the pattern of presence across the year, the relative probability of presence is calculated. This is the probability of presence divided by the maximum probability of presence across all weeks. For example, imagine the probability of presence in week 20 for the Spotted Towhee is 0.05, and that the probability of presence at week 12 (0.25) is the maximum of any week of the year. The relative probability of presence on week 12 is 0.25/0.25 = 1; at week 20 it is 0.05/0.25 = 0.2. 3. The relative probability of presence calculated in the previous step undergoes a statistical conversion so that all possible values fall between 0 and 10, inclusive. This is the probability of presence score. To see a bar's probability of presence score, simply hover your mouse cursor over the bar. Breeding Season () Yellow bars denote a very liberal estimate of the time-frame inside which the bird breeds across its entire range. If there are no yellow bars shown for a bird, it does not breed in your project area. Survey E ort () Vertical black lines superimposed on probability of presence bars indicate the number of surveys performed for that species in the 10km grid cell(s) your project area overlaps. The number of surveys is expressed as a range, for example, 33 to 64 surveys. To see a bar's survey e ort range, simply hover your mouse cursor over the bar. No Data () A week is marked as having no data if there were no survey events for that week. Survey Timeframe no data survey e ort breeding season probability of presence Surveys from only the last 10 years are used in order to ensure delivery of currently relevant information. The exception to this is areas o the Atlantic coast, where bird returns are based on all years of available data, since data in these areas is currently much more sparse. SPECIES JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Bald Eagle Non-BCC Vulnerable Black Rosy- nch BCC Rangewide (CON) Evening Grosbeak BCC Rangewide (CON) Western Grebe BCC Rangewide (CON) Tell me more about conservation measures I can implement to avoid or minimize impacts to migratory birds. Nationwide Conservation Measures describes measures that can help avoid and minimize impacts to all birds at any location year round. Implementation of these measures is particularly important when birds are most likely to occur in the project area. When birds may be breeding in the area, identifying the locations of any active nests and avoiding their destruction is a very helpful impact minimization measure. To see when birds are most likely to occur and be breeding in your project area, view the Probability of Presence Summary. Additional measures or permits may be advisable depending on the type of activity you are conducting and the type of infrastructure or bird species present on your project site. What does IPaC use to generate the list of migratory birds that potentially occur in my speci ed location? The Migratory Bird Resource List is comprised of USFWS Birds of Conservation Concern (BCC)and other species that may warrant special attention in your project location. The migratory bird list generated for your project is derived from data provided by the Avian Knowledge Network (AKN). The AKN data is based on a growing collection of survey, banding, and citizen science datasets and is queried and ltered to return a list of those birds reported as occurring in the 10km grid cell(s) which your project intersects, and that have been identi ed as warranting special attention because they are a BCC species in that area, an eagle (Eagle Act requirements may apply), or a species that has a particular vulnerability to o shore activities or development. Again, the Migratory Bird Resource list includes only a subset of birds that may occur in your project area. It is not representative of all birds that may occur in your project area. To get a list of all birds potentially present in your project area, please visit the Rapid Avian Information Locator (RAIL) Tool. What does IPaC use to generate the probability of presence graphs for the migratory birds potentially occurring in my speci ed location? The probability of presence graphs associated with your migratory bird list are based on data provided by the Avian Knowledge Network (AKN). This data is derived from a growing collection of survey, banding, and citizen science datasets. Probability of presence data is continuously being updated as new and better information becomes available. To learn more about how the probability of presence graphs are produced and how to interpret them, go the Probability of Presence Summary and then click on the "Tell me about these graphs" link. How do I know if a bird is breeding, wintering or migrating in my area? To see what part of a particular bird's range your project area falls within (i.e. breeding, wintering, migrating or year-round), you may query your location using the RAIL Tool and look at the range maps provided for birds in your area at the bottom of the pro les provided for each bird in your results. If a bird on your migratory bird species list has a breeding season associated with it, if that bird does occur in your project area, there may be nests present at some point within the timeframe speci ed. If "Breeds elsewhere" is indicated, then the bird likely does not breed in your project area. What are the levels of concern for migratory birds? Migratory birds delivered through IPaC fall into the following distinct categories of concern: 1. "BCC Rangewide" birds are Birds of Conservation Concern (BCC) that are of concern throughout their range anywhere within the USA (including Hawaii, the Paci c Islands, Puerto Rico, and the Virgin Islands); 2. "BCC - BCR" birds are BCCs that are of concern only in particular Bird Conservation Regions (BCRs) in the continental USA; and 3. "Non-BCC - Vulnerable" birds are not BCC species in your project area, but appear on your list either because of the Eagle Act requirements (for eagles) or (for non-eagles) potential susceptibilities in o shore areas from certain types of development or activities (e.g. o shore energy development or longline shing). Although it is important to try to avoid and minimize impacts to all birds, e orts should be made, in particular, to avoid and minimize impacts to the birds on this list, especially eagles and BCC species of rangewide concern. For more information on conservation measures you can implement to help avoid and minimize migratory bird impacts and requirements for eagles, please see the FAQs for these topics. Details about birds that are potentially a ected by o shore projects For additional details about the relative occurrence and abundance of both individual bird species and groups of bird species within your project area o the Atlantic Coast, please visit the Northeast Ocean Data Portal. The Portal also o ers data and information about other taxa besides birds that may be helpful to you in your project review. Alternately, you may download the bird model results les underlying the portal maps through the NOAA NCCOS Integrative Statistical Modeling and Predictive Mapping of Marine Bird Distributions and Abundance on the Atlantic Outer Continental Shelf project webpage. Bird tracking data can also provide additional details about occurrence and habitat use throughout the year, including migration. Models relying on survey data may not include this information. For additional information on marine bird tracking data, see the Diving Bird Study and the nanotag studies or contact Caleb Spiegel or Pam Loring. What if I have eagles on my list? If your project has the potential to disturb or kill eagles, you may need to obtain a permit to avoid violating the Eagle Act should such impacts occur. Proper Interpretation and Use of Your Migratory Bird Report The migratory bird list generated is not a list of all birds in your project area, only a subset of birds of priority concern. To learn more about how your list is generated, and see options for identifying what other birds may be in your project area, please see the FAQ "What does IPaC use to generate the migratory birds potentially occurring in my speci ed location". Please be aware this report provides the "probability of presence" of birds within the 10 km grid cell(s) that overlap your project; not your exact project footprint. On the graphs provided, please also look carefully at the survey e ort (indicated by the black vertical bar) and for the existence of the "no data" indicator (a red horizontal bar). A high survey e ort is the key component. If the survey e ort is high, then the probability of presence score can be viewed as more dependable. In contrast, a low survey e ort bar or no data bar means a lack of data and, therefore, a lack of certainty about presence of the species. This list is not perfect; it is simply a starting point for identifying what birds of concern have the potential to be in your project area, when they might be there, and if they might be breeding (which means nests might be present). The list helps you know what to look for to con rm presence, and helps guide you in knowing when to implement conservation measures to avoid or minimize potential impacts from your project activities, should presence be con rmed. To learn more about conservation measures, visit the FAQ "Tell me about conservation measures I can implement to avoid or minimize impacts to migratory birds" at the bottom of your migratory bird trust resources page. Coastal Barrier Resources System Projects within the John H. Chafee Coastal Barrier Resources System (CBRS) may be subject to the restrictions on Federal expenditures and nancial assistance and the consultation requirements of the Coastal Barrier Resources Act (CBRA) (16 U.S.C. 3501 et seq.). For more information, please contact the local Ecological Services Field O ce or visit the CBRA Consultations website. The CBRA website provides tools such as a ow chart to help determine whether consultation is required and a template to facilitate the consultation process. There are no known coastal barriers at this location. Data limitations The CBRS boundaries used in IPaC are representations of the controlling boundaries, which are depicted on the o cial CBRS maps. The boundaries depicted in this layer are not to be considered authoritative for in/out determinations close to a CBRS boundary (i.e., within the "CBRS Bu er Zone" that appears as a hatched area on either side of the boundary). For projects that are very close to a CBRS boundary but do not clearly intersect a unit, you may contact the Service for an o cial determination by following the instructions here: https://www.fws.gov/service/coastal-barrier-resources-system-property-documentation Data exclusions CBRS units extend seaward out to either the 20- or 30-foot bathymetric contour (depending on the location of the unit). The true seaward extent of the units is not shown in the CBRS data, therefore projects in the o shore areas of units (e.g., dredging, breakwaters, o shore wind energy or oil and gas projects) may be subject to CBRA even if they do not intersect the CBRS data. For additional information, please contact CBRA@fws.gov. Facilities National Wildlife Refuge lands Any activity proposed on lands managed by the National Wildlife Refuge system must undergo a 'Compatibility Determination' conducted by the Refuge. Please contact the individual Refuges to discuss any questions or concerns. There are no refuge lands at this location. Fish hatcheries There are no sh hatcheries at this location. Wetlands in the National Wetlands Inventory (NWI) Impacts to NWI wetlands and other aquatic habitats may be subject to regulation under Section 404 of the Clean Water Act, or other State/Federal statutes. For more information please contact the Regulatory Program of the local U.S. Army Corps of Engineers District. Wetland information is not available at this time This can happen when the National Wetlands Inventory (NWI) map service is unavailable, or for very large projects that intersect many wetland areas. Try again, or visit the NWI map to view wetlands at this location. Data limitations The Service's objective of mapping wetlands and deepwater habitats is to produce reconnaissance level information on the location, type and size of these resources. The maps are prepared from the analysis of high altitude imagery. Wetlands are identi ed based on vegetation, visible hydrology and geography. A margin of error is inherent in the use of imagery; thus, detailed on-the-ground inspection of any particular site may result in revision of the wetland boundaries or classi cation established through image analysis. The accuracy of image interpretation depends on the quality of the imagery, the experience of the image analysts, the amount and quality of the collateral data and the amount of ground truth veri cation work conducted. Metadata should be consulted to determine the date of the source imagery used and any mapping problems. Wetlands or other mapped features may have changed since the date of the imagery or eld work. There may be occasional di erences in polygon boundaries or classi cations between the information depicted on the map and the actual conditions on site. Data exclusions Certain wetland habitats are excluded from the National mapping program because of the limitations of aerial imagery as the primary data source used to detect wetlands. These habitats include seagrasses or submerged aquatic vegetation that are found in the intertidal and subtidal zones of estuaries and nearshore coastal waters. Some deepwater reef communities (coral or tuber cid worm reefs) have also been excluded from the inventory. These habitats, because of their depth, go undetected by aerial imagery. Data precautions Federal, state, and local regulatory agencies with jurisdiction over wetlands may de ne and describe wetlands in a di erent manner than that used in this inventory. There is no attempt, in either the design or products of this inventory, to de ne the limits of proprietary jurisdiction of any Federal, state, or local government or to establish the geographical scope of the regulatory programs of government agencies. Persons intending to engage in activities involving modi cations within or adjacent to wetland areas should seek the advice of appropriate Federal, state, or local agencies concerning speci ed agency regulatory programs and proprietary jurisdictions that may a ect such activities. Wheeler Gulch Solar Project D Geotechnical Report Wheeler Gulch Solar Project This page intentionally left blank. Geotechnical Engineering Report Proposed Solar Farm County Road 215 Parachute, Colorado GEG Project No. 222-156 December 17, 2022 Copyright 2022 Granite Engineering Group, Inc. All Rights Reserved ONLY THE CLIENT OR ITS DESIGNATED REPRESENTATIVES MAY USE THIS DOCUMENT AND ONBLY FOR THE SPECIFIC PROJECT THAT THIS REPORT WAS PREPARED FOR. Page ii of v A Report Prepared for: Mr. Gary Coons Fusion Industries, LLC 205 NW 63rd Street, Suite 170 Oklahoma City, Oklahoma 73116 GEOTECHNICAL ENGINEERING REPORT PROPOSED SOLAR FARM COUNTY ROAD 215 PARACHUTE, COLORADO GEG PROJECT NO. 222-156 December 17, 2022 Prepared by: ___________________________ Hai Ming Lim, PE Project Manager ___________________________ Xuhui Chang Senior Engineer GRANITE ENGINEERING GROUP, INC. 3927 Van Teylingen Dr. Colorado Springs, CO 80917 Phone: 719-716-9009 12-21-22 Page iii of v Table Of Contents 1. INTRODUCTION ................................................................................................................................................ 1 GENERAL ...................................................................................................................................................... 1 PROJECT INFORMATION ............................................................................................................................... 1 PURPOSE AND SCOPE .................................................................................................................................. 1 2. SUBSURFACE EXPLORATION ...................................................................................................................... 2 FIELD EXPLORATION .................................................................................................................................... 2 FIELD SOIL ELECTRICAL RESISTIVITY TESTING ........................................................................................... 3 LABORATORY TESTING................................................................................................................................. 4 3. SITE AND SUBSURFACE CONDITIONS ...................................................................................................... 4 SITE CONDITIONS ......................................................................................................................................... 4 GEOLOGIC SETTING ..................................................................................................................................... 5 SUBSURFACE CONDITIONS .......................................................................................................................... 5 GROUNDWATER ............................................................................................................................................ 6 4. CONSTRUCTION RECOMMENDATIONS .................................................................................................... 6 GEOTECHNICAL FEASIBILITY ........................................................................................................................ 6 PRIMARY GEOTECHNICAL CONCERNS ......................................................................................................... 7 4.2.1 Swell Potential of Foundation Soils ............................................................................................. 7 CONSTRUCTION CONSIDERATIONS .............................................................................................................. 7 4.3.1 Site Preparation and Grading ....................................................................................................... 7 4.3.2 Excavation and Trench Construction .......................................................................................... 8 4.3.3 Structural and Engineered Fill Requirements ............................................................................ 9 4.3.4 Compaction Requirements ......................................................................................................... 10 4.3.5 Utility Trench Backfill .................................................................................................................... 11 4.3.6 Drainage Considerations ............................................................................................................. 12 4.3.7 Construction in Wet or Cold Weather ........................................................................................ 12 4.3.8 Corrosion Potential and Concrete Type .................................................................................... 12 4.3.9 Thermal Resistivity Evaluations ................................................................................................. 13 5. FOUNDATION DESIGN RECOMMENDATIONS ....................................................................................... 15 5.1 DRIVEN POST FOUNDATIONS ..................................................................................................................... 15 5.1.1 Foundation Soils Preparation ..................................................................................................... 16 5.1.2 Direct-Drive Post Axial Capacity ................................................................................................ 16 5.1.3 Direct-Drive Post Lateral Capacity ............................................................................................. 17 5.1.4 Driveability Analysis ..................................................................................................................... 17 5.1.5 Predrilling ....................................................................................................................................... 18 5.1.6 Verification Load Testing ............................................................................................................. 18 Page iv of v 5.2 SUBSTATION EQUIPMENT FOUNDATIONS .................................................................................................. 18 5.2.1 Foundation Soils Preparation ..................................................................................................... 18 5.2.2 Equipment Pad and Footing Foundations ................................................................................ 19 SEISMICITY ................................................................................................................................................. 20 6. PAVEMENT THICKNESS RECOMMENDATIONS .................................................................................... 20 6.1 ANTICIPATED SUBGRADE AND SUBGRADE PREPARATION ........................................................................ 21 6.2 AGGREGATE SURFACING PAVEMENT THICKNESS DESIGN ....................................................................... 21 6.3 ASPHALT AND CONCRETE PAVEMENT THICKNESS DESIGN ...................................................................... 22 PAVEMENT MATERIALS .............................................................................................................................. 23 6.4.1 Base Course ................................................................................................................................. 23 6.4.2 Hot Mix Asphalt ............................................................................................................................. 23 6.4.3 Portland Cement Concrete ......................................................................................................... 23 DRAINAGE ................................................................................................................................................... 23 PAVEMENT MAINTENANCE ......................................................................................................................... 23 7. LIMITATIONS ................................................................................................................................................... 24 Page v of v List Of Figure FIGURE 3-1. GEOLOGIC MAP ........................................................................................................................... 5 List Of Tables TABLE 4-1 IMPORTED STRUCTURAL FILL CRITERIA .......................................................................................... 10 TABLE 4-2 SUBGRADE PREPARATION AND FILL PLACEMENT CRITERIA ............................................................. 10 TABLE 4-3. ANALYTICAL TEST RESULTS ......................................................................................................... 12 TABLE 4-4. RESISTIVITY AND CORROSIVITY CATEGORIES ................................................................................ 13 TABLE 4-5. THERMAL RESISTIVITY SAMPLES ................................................................................................... 14 TABLE 4-6. RECOMMENDED DESIGN THERMAL RESISTIVITY VALUES ................................................................ 15 TABLE 5-1. RECOMMENDED DIRECT-DRIVE POST GEOTECHNICAL AXIAL CAPACITY .......................................... 16 TABLE 5-2. RECOMMENDED L-PILE PARAMETERS ........................................................................................... 17 TABLE 5-3. VERTICAL TOLERANCE AND OVER-EXCAVATION DEPTHS ............................................................... 18 TABLE 5-4. DESIGN ACCELERATION FOR SHORT PERIODS ............................................................................... 20 TABLE 6-1. RECOMMENDED MINIMUM AGGREGATE ROADWAY THICKNESS ....................................................... 21 TABLE 6-2. RECOMMENDED MINIMUM AGGREGATE ROADWAY THICKNESS ....................................................... 22 TABLE 6-3. RECOMMENDED MINIMUM PAVEMENT SECTIONS ........................................................................... 22 List Of Appendices FIGURE A-1: SITE LOCATION PLAN .....................................................................................................................A FIGURE A-2: BORING LOCATION PLAN ..............................................................................................................A KEY TO BORING LOGS............................................................................................................................................ B BORING LOGS ........................................................................................................................................................... B LABORATORY TEST RESULTS ............................................................................................................................. C FIELD ELETRICAL RESISTIVITY TEST RESULTS ............................................................................................ D Proposed Solar Farm GEG Project No. 222-156 Parachute, Colorado December 17, 2022 1 | P a g e 1. INTRODUCTION General Granite Engineering Group, Inc. (GEG) has completed the subsurface exploration and geotechnical engineering evaluation for the proposed solar farm located west of the intersection of County Road 215 and Garden Gulch Road, approximately 3.5 miles northwest of Parachute, Colorado. The general location of the project site is presented on Figure A-1, Site Location Plan in Appendix A. This report includes our recommendations related to the geotechnical aspects of the project design and construction. Conclusions and recommendations presented in this report are based on the subsurface information encountered at the locations of our exploration, preliminary information provided to us, and the provision and requirements outlined in the Limitations section of this report. Project Information Based on information provided to us, the project will include solar panels supported potentially on driven C-channels, a substation, and associated paved or gravel-surfacing drives. The substation equipment is anticipated to be supported on cast-in-place concrete or prefabricated concrete slabs/mats supported on-grade or shallow spread footings. We anticipate bearing pressures below equipment pads will be relatively low and will not exceed 2,000 pounds per square foot (psf). Grading plans were also not available at the time of preparing this report; and it was assumed that maximum cut and fill depths of up to 2 feet are anticipated to be required to reach the final grade. If the type of construction is to vary significantly from the above descriptions, GEG should be notified immediately in order to re-evaluate our recommendations, if required. Once the final design such as grading plan is established, GEG should be allowed to review the engineering recommendations. Purpose and Scope The purpose of our study was to evaluate the subsurface conditions at the locations of the proposed construction and provide associated geotechnical engineering recommendations for the Proposed Solar Farm GEG Project No. 222-156 Parachute, Colorado December 17, 2022 2 | P a g e design and construction of foundations for the proposed solar panels and substation equipment, and pavements. This report has been prepared in general accordance with our approved proposal for geotechnical engineering services, dated September 22, 2022. Our scope of services consisted of the following: Review available mapped geology at the site. Arrange for the underground utility locate. Conduct a subsurface exploration to evaluate the subsurface conditions. The subsurface exploration included five (5) borings to approximately 15 to 20 feet below the existing ground surface (bgs). The approximate boring locations are shown on Figure A-2, Boring Location Plan in Appendix A. Perform electrical resistivity tests in accordance with 4-pin Wenner test method with spacing up to25 feet. Perform laboratory testing on soil samples obtained from the subsurface exploration to evaluate engineering characteristics. Prepare a report that presents the results of encountered site and subsurface conditions, laboratory testing, geotechnical engineering analyses, geotechnical feasibility, design and recommendations for the proposed structure foundation systems, pavement thickness design, and earthwork. The conclusions and recommendations presented herein are based on our limited site explorations and the subsurface conditions encountered at our boring locations during the time of our exploration. Our findings, conclusions, and recommendations should not be extrapolated to other areas of the site or used for other projects without our prior review. Additionally, they should not be used if the site has been altered or if more than three (3) years has elapsed since the date of our final report without our prior review to determine if they remain valid. 2. SUBSURFACE EXPLORATION Field Exploration Our field exploration program consisted of advancing a total of five (5) borings at the project site as shown on Figure A-2, Boring Location Plan in Appendix A. Proposed Solar Farm GEG Project No. 222-156 Parachute, Colorado December 17, 2022 3 | P a g e The boring locations were established in the field by GEG personnel by using a hand-held GPS unit with accuracy of approximately 10 feet. The boring locations should be considered accurate only to the degree implied by the method used to define them. The borings were advanced to depths of about 15 to 20 feet bgs with a rubber track ATV mounted CME-55 drill rig equipped with 4-inch diameter, solid-stem, continuous-flight augers. Sampling was performed at approximately 2.5-foot intervals within the top 10 feet, and at 5-foot intervals thereafter to the terminated depths. Samples were collected by driving a standard penetration test (SPT) or Modified California (MC) split barrel samplers into the strata with a 140-pound hammer falling 30-inches. The SPT is a 1.375-inch I.D. standard split barrel sampler performed in accordance with ASTM D1586. The Modified California (MC) sampler is a 2.5-inch O.D., 2.0-inch ID (1.95-inch ID with liners), split barrel sampler with internal liners, performed in accordance with ASTM D3550. The blows required to drive the SPT sampler the final 12-inches are known as the SPT N-value. The MC Sampler “Penetration Resistance” refers to the sum of all blows required to drive the sampler the drive length of the final 12 inches or portion thereof. The SPT N-value and the MC penetration resistance represent the consistency or relative density of the strata. The boring logs along with the key to the logs are presented in Appendix B. Field Soil Electrical Resistivity Testing Field soil resistivity testing was performed at two (2) locations (B-2 and B-4) using the Wenner four-point method in accordance with ASTM G57. The Wenner method uses four equally spaced metal probes or electrodes driven into the ground, along a straight line. An alternating current is applied across the outer two probes, and voltage is measured across the inner probes. Using Ohm’s Law (R=V/I), the resistance value is calculated. The apparent soil resistivity is the average resistance of the soil mass along the electrical field lines from the ground surface to a depth approximately equal to the distance between probes, and calculated as followings: ρ = A 2 π R Where: ρ = apparent soil resistivity (ohm-cm) A = distance between the electrodes (cm) R = measured resistance (ohms) π= constant pi (3.1416) Proposed Solar Farm GEG Project No. 222-156 Parachute, Colorado December 17, 2022 4 | P a g e Resistance measurements were conducted with probe spacing of 1, 2, 5, 10, 15, 20, and 25 feet. The probes used in the field soil resistivity tests are metal probes with a diameter of 0.5 an inch, and length of 18 inches. The probes were driven into the ground with a minimum penetration of 6-inches at the selected spacing. The results of the field electrical resistivity tests are included in Appendix D. Laboratory Testing Representative soil samples were selected for laboratory testing that was completed in accordance with industry standards and consistent with local practice. Laboratory soil testing included: Description and identification of soils (visual-manual procedure) Natural moisture; Gradation analysis; Atterberg limits; Standard Proctor; Swell-consolidaton; Thermal resistivity; Analytical tests including water soluble sulfates and chlorides; soil resistivity; pH. Laboratory tests are shown on the boring logs and in the Laboratory Summary in Appendix C. Two composite samples were prepared. Composite sample 1 was obtained by combining the top 5 feet of subgrade samples from Borings B-1 through B-3. Composite sample 2 was obtained by combining the top 5 feet of subgrade samples from Borings B-4 and B-5. Standard Proctor and thermal resistivity tests were performed on both composite sample 1 and sample 2. Analytical tests were performed on composite sample 1. 3. SITE AND SUBSURFACE CONDITIONS Site Conditions The site is located west of the intersection of County Road 215 and Garden Gulch Road, approximately 3.5 miles northwest of Parachute, Colorado. The site is currently vacant and generally covered with grass and bush-type vegetation with some dirt or gravel roads. The site appeared to be sloping gently towards the west. The site is located near an industrial area. Proposed Solar Farm GEG Project No. 222-156 Parachute, Colorado December 17, 2022 5 | P a g e Geologic Setting Review of the “Geologic Units of Colorado, 1979” indicates that the site is located within gravel and alluviums, and Wasatch Formation and Ohio Creek Formation. Gravel and alluviums consist of clay, silt, sand and gravel. Wasatch Formation and Ohio Creek Formation consist primarily of claystone with mudstone, sandstone and conglomerate. The geologic units mapped at the project site are presented in Figure 3-1. The WebSoil Survey provided by Natural Resources Conservation Service (NRCS) indicates that the surficial soil at the site is Arvada loam and Halaquepts. Arvada loam consists of loam and silty clay loam. Halaquepts consist of clay loam, loam, and stratified very gravelly cobbly sand. Figure 3-1. Geologic Map Subsurface Conditions The borings encountered lean clay with varying amounts of sand, and sand with varying amounts of silt and clay to a depth of about 14 feet bgs in Boring B-2, and to the boring termination depths of about 15 to 20 feet bgs in the remaining borings. Below the lean clay soils, boring B-2 encountered claystone to the boring termination depth of about 15 feet bgs. Proposed Solar Farm GEG Project No. 222-156 Parachute, Colorado December 17, 2022 6 | P a g e The lean clay soils were tan and brown in color and medium stiff to very stiff in consistency. The sandy soils were tan in color and loose to medium dense in relative density. The claystone was olive mottled with rust in color and was decomposed and extremely soft in hardness. The boring logs in Appendix B present detailed results of the subsurface exploration. Groundwater Groundwater was measured during drilling and immediately after boring completion. Groundwater was observed at a depth of about 13 feet bgs in Boring B-1 during drilling and immediately after boring completion and was not observed in the remaining borings at these times during our field exploration. Groundwater observations are representative of conditions at the time of our field exploration, and therefore may not be indicative of groundwater levels at other times of the year or at other locations across the site. Groundwater conditions may fluctuate with seasonal precipitation, site grading and improvements, and local irrigation practices. 4. CONSTRUCTION RECOMMENDATIONS Geotechnical Feasibility Subsurface conditions encountered at the site during the field exploration did not find conditions that would preclude the construction of the project as planned provided the conclusions and recommendations presented in the following sections are incorporated into the project design. The primary geotechnical concern for the proposed construction is swell potential of the native clayey soils encountered at the site. The recommendations submitted herein are based, in part, upon data obtained from our subsurface exploration. The nature and extent of subsurface variations that may exist at the proposed project site will not become evident until construction. If variations appear evident, then the recommendations presented in this report should be evaluated. In the event that any changes in the nature, design, or location of the proposed project are planned, the conclusions and recommendations contained in this report will not be considered valid unless the changes are reviewed, and our recommendations modified in writing. Proposed Solar Farm GEG Project No. 222-156 Parachute, Colorado December 17, 2022 7 | P a g e Primary Geotechnical Concerns 4.2.1 Swell Potential of Foundation Soils The native clayey soils encountered in the borings at the site can have swell potential ranging from 0 to 3.5 percent under a surcharge pressure of 200 psf, and swell pressure up to 2,000 psf. These materials are generally classified as low to moderate category by Colorado Association of Geotechnical Engineers (CAGE) for slab performance and foundation movement. Potentially expansive soils will require particular attention in the design and construction. Expansive soils are stable at current and constant moisture conditions. Upon drying, these soils will shrink, which would cause settlement of foundation and slab-on-grade. Upon wetting, these soils would increase in volume and cause movement and damage. The amount of movement and/or damage is dependent on the subgrade preparation, availability of water due to landscape irrigation and surface drainage, and the structural tolerances to movement. Construction Considerations 4.3.1 Site Preparation and Grading Site preparation and earthwork operations should be performed in accordance with applicable codes, safety regulations and other local, state, or federal guidelines. Earthwork on the project should be observed and evaluated by GEG. The evaluation of earthwork should include observation and testing of subgrade preparation, foundation bearing soils and other geotechnical conditions exposed during project construction. Areas within the limits of construction should be stripped and cleared of surface vegetation, topsoil, and any debris. All surface and subsurface features from past site use should be removed full depth. Stripped materials consisting of vegetation, organic materials and debris should be wasted from the site or used to revegetate landscaped areas after completion of grading operations. Exposed surfaces should be free of mounds and depressions in order to promote uniform compaction. The substation equipment foundations are anticipated to bear on native low to moderate expansive clay soils. To minimize the swell potential of the foundation soils, the foundation soils should be over-excavated, moisture-conditioned and recompacted, or replace with structural fill as discussed in Section 5.2.1 of this report. Proposed Solar Farm GEG Project No. 222-156 Parachute, Colorado December 17, 2022 8 | P a g e Following initial stripping and grading, all exposed areas which will receive fill or support structures, once properly cleared, should be scarified to a minimum depth of 8 inches, moisture conditioned, and compacted according to Section 4.3.4 of this report. Following any required undercutting and moisture conditioning, and prior to placement of structural fill or engineered fill, it is recommended that the subgrade be proof rolled. Proof rolling of the subgrade aids in identifying soft or disturbed areas. Soft and unsuitable areas identified by proof rolling should be undercut and replaced with structural fill or engineered fill. Proof rolling can be accomplished through use of a loaded, tandem-axle dump truck or similar equipment providing an equivalent subgrade loading. Suitable structural fill or engineered fill should be placed to design grade as soon as practical after reworking the subgrade to avoid moisture changes in the underlying soils. Fill material should be placed on a horizontal plane and placed in loose lifts not to exceed 8 inches thick, unless otherwise accepted by GEG. The moisture content and compaction of subgrade soil and structural fill or engineered fill should be maintained until slab construction. Based upon the subsurface conditions encountered, subgrade soils exposed during construction are anticipated to be relatively stable. However, the stability of the subgrade may be affected by precipitation, repetitive construction traffic and other factors. If unstable conditions are encountered or develop during construction, stability may be improved by scarifying and drying the subgrade soils. Over excavation of wet zones and replacement with structural fill or crushed rock may be necessary. If areas are found to be unsuitable for re-work, additional stabilization will be required. If additional stabilization is required, GEG should be contacted to evaluate the conditions in the field, and a suitable stabilization method can be provided. In addition, any soft and/or wet areas exposed during the excavation may need to be stabilized prior to the placement of new fill to create a stable, firm construction platform. A typical stabilization method may include utilizing gravel with the combination of geo-grid (e.g. Tensar TX160) to create a stable base. Other stabilization methods may also be appropriate. 4.3.2 Excavation and Trench Construction Excavations into the on-site soils will encounter a variety of conditions. Based on laboratory testing, the dry density of in-place near surface native soils is about the same as 95 percent of Standard Proctor dry density. A shrinkage value of 0 percent and a hauling bulkage value of 10 to 15 percent may be used for estimating earthwork volumes. Proposed Solar Farm GEG Project No. 222-156 Parachute, Colorado December 17, 2022 9 | P a g e All excavations must comply with the applicable local, State, and Federal safety regulations, and particularly with the excavation standards of the Occupational Safety and Health Administration (OSHA). Construction site safety, including excavation safety, is the sole responsibility of the Contractor as part of its overall responsibility for the means, methods, and sequencing of construction operations. GEG recommendations for excavation support is provided for the Client’s sole use in planning the project, in no way do they relieve the Contractor of its responsibility to construct, support, and maintain safe slopes. Under no circumstances should the following recommendations be interpreted to mean that GEG is assuming responsibility for either construction site safety or the Contractor’s activities. We believe the native soil encountered at this site will classify as a Type C material, using OSHA criteria. OSHA requires that unsupported cuts be no steeper than 1½H:1V for Type C material for unbraced excavations up to 20 feet in height. In general, we believe that these slope ratios will be temporarily stable under unsaturated conditions. Flattened slopes may be required if excavations encounter groundwater, or the slopes will be exposed for an extended period of time. Please note that the Contractor’s OSHA-qualified “competent person” must make the actual determination of soil type and allowable sloping in the field. The soils encountered by the proposed excavations may vary significantly across the site. The preliminary classifications presented above are based solely on the materials encountered in widely spaced exploratory test borings. The contractor should confirm that similar conditions exist throughout the proposed area of excavation. As a safety measure, it is recommended that all vehicles and soil piles be kept to a lateral distance equal to at least the depth of the excavation from the crest of the slope. The exposed slope face should be protected against the elements and monitored by the contractor on at least a daily basis. 4.3.3 Structural and Engineered Fill Requirements Based on our laboratory test results, the on-site clay and sand soils may be utilized as engineered fill placed beneath shallow foundations, slabs on-grade elements and pavements provided that they are properly over-excavated, moisture conditioned and compacted. Additional imported structural fill, if required, should consist of non-expansive granular material meeting the following criteria: Proposed Solar Farm GEG Project No. 222-156 Parachute, Colorado December 17, 2022 10 | P a g e Table 4-1 Imported Structural Fill Criteria Gradation Requirements Standard Sieve Size Percent Passing 2 inches 100 No. 200 10 – 30 Plasticity Requirements (Atterberg Limits) Liquid Limit 30 or less Plasticity Index 6 or less We recommend that a qualified representative of GEG visit the site during excavation and during placement of the structural fill and engineered fill to confirm the soils exposed in the excavations are consistent with those encountered during our subsurface explorations and that proper foundation subgrade preparation and placement are performed. All fill placed on this site should be compacted according to the recommendations in Section 4.3.4 of this report. Fill to be placed at this site during leveling/grading operations should be placed under controlled conditions. A sample of any imported fill material, if required, should be submitted to GEG for approval and testing at least 3 days prior to stockpiling at the site. 4.3.4 Compaction Requirements Fill materials should be placed in horizontal lifts compatible with the type of compaction equipment being used, moisture conditioned, and compacted in accordance with the criteria shown in Table 4-2. Table 4-2 Subgrade Preparation and Fill Placement Criteria Fill Location Material Type Percent Compaction (ASTM Method) Moisture Content Foundation and Subgrade Soils On Site Clay and Sand (engineered fill) 95 minimum (ASTM D698) OMC to +3% Imported Structural Fill 95 minimum (ASTM D1557) 2 % of OMC Trench Backfill On Site Clay and Sand (engineered fill) 92 minimum (ASTM D698) OMC to +3% Imported Structural Fill 92 minimum (ASTM D1557) 2 % of OMC Proposed Solar Farm GEG Project No. 222-156 Parachute, Colorado December 17, 2022 11 | P a g e Fill Location Material Type Percent Compaction (ASTM Method) Moisture Content Aggregate Base (ABC) Imported CDOT Class 5 or 6 ABC 95 minimum (ASTM D1557) 2 % of OMC OMC= Optimum Moisture Content determined from Proctor Test Fill should be placed in level lifts not exceeding 8-inches in loose thickness and compacted to the specified percent compaction to produce a firm and unyielding surface. If field density tests indicate the required percent compaction has not been obtained, the fill material should be reconditioned as necessary and re-compacted to the required percent compaction before placing any additional material. 4.3.5 Utility Trench Backfill On-site soils may be utilized as backfill material in utility trenches provided the backfill is essentially free of plant matter, organic soil, debris, trash, other deleterious matter and rock particles larger than 2-inches. Backfill should be placed in lifts of 8-inches or less in loose thickness and compacted with appropriate trench equipment. Utility trench backfill should be compacted as recommended in Section 4.3.4 of this report. A “trenchless” plowing installation method (e.g. Palmer Plow) could also be used for the cable installations. This trenchless method is to plow through the ground with a blade that is approximately 6 to 8 inches wide and the cables are installed during the process through the opening of the blade. We expect that the cable installation will extend to approximately 3- to 4- foot below the finished grade for the cable installations. Based on the subsurface conditions encountered in the borings, this trenchless plowing installation method is feasible at this site. The trenchless plowing method typically will fill in the plow alignment. Soils with higher percentage of granular materials such as sand will fill in better than soils with higher percentage of cohesive clay soils. Because the presence of clay soils near the surface at this site, we recommend that the surface of the plow alignment be scarified to 8-inches below the existing ground surface, and recompacted in accordance with Section 4.3.4 of this report. In areas where trenchless plowing installation was performed, it is possible that depressions may occur over time and may require monitoring and maintaining as necessary. Proposed Solar Farm GEG Project No. 222-156 Parachute, Colorado December 17, 2022 12 | P a g e 4.3.6 Drainage Considerations Positive drainage should be provided during construction and maintained throughout the life of the proposed project. Proper design of drainage should include prevention of ponding water on or immediately adjacent to the structures. Surface features that could retain water in areas adjacent to the structures should be eliminated. Backfill against any kind of structures and in utility line trenches should be well compacted and free of all construction debris to reduce the possibility of moisture infiltration and migration. Concentrated runoff should be avoided in areas susceptible to erosion and slope instability. Slopes and other stripped areas should be protected against erosion by re-vegetation or other methods. 4.3.7 Construction in Wet or Cold Weather Grading fill, structural fill or other fill should not be placed on frosted or frozen ground, nor should frozen material be placed as fill. Frozen ground should be allowed to thaw or be completely removed prior to placement of fill. A good practice is to cover the compacted fill with a “blanket” of loose fill to help prevent the compacted fill from freezing. Concrete and asphalt structures should not be constructed on frozen soil. Frozen soil should be completely removed from beneath the concrete elements, or thawed, scarified and re-compacted. The amount of time passing between excavation or subgrade preparation and placing concrete should be minimized during freezing conditions to prevent the prepared soils from freezing. Blankets, soil cover, or heating as required may be utilized to prevent the subgrade from freezing. 4.3.8 Corrosion Potential and Concrete Type Analytical testing was completed on composite sample 1 obtained from the top 5 feet of subgrade samples from Borings B-1 through B-3. The test results are presented in Appendix C and are summarized in Table 4-3. Table 4-3. Analytical Test Results Sample Materials Water Soluble Sulfates, % Water Soluble Chlorides, % pH Resistivity, ohm.cm Comp 1 Lean Clay w Sand 0.1954 0.0133 8.1 600 The concentration of water-soluble sulfates measured in the sample that was tested was 0.1954 percent. This concentration of water-soluble sulfates represents a Class 1 degree of sulfate attack on concrete exposed to the existing foundation soils. The degree of sulfate attack is based Proposed Solar Farm GEG Project No. 222-156 Parachute, Colorado December 17, 2022 13 | P a g e on a range of Class 0 (negligible) to Class 3 (very severe) as described in the American Concrete Institute (ACI) Standard 201.2R, “Guide to Durable Concrete”. Results of soluble sulfate testing indicate that ASTM C150 Type II cement should be specified for all project concrete on and below grade. The pH and electrical resistivity were also tested for the sample of the existing foundation soils from the geotechnical borings. Test results measured a pH value of 8.1, and resistivity measurement had a value of 600 ohm-centimeters for the soil sample that was tested. Corrosion of buried metal is an electrochemical process in which the amount of metal loss due to corrosion is directly proportional to the flow of electrical current (DC) from metal into the soil. As resistivity decreases, the corrosivity of the soil increases. The following table provides a correlation between soil resistivity and corrosivity towards ferrous metal. Table 4-4. Resistivity and Corrosivity Categories Resistivity in Ohm-centimeters Corrosivity Category 0 to 1,000 Severely Corrosive 1,000 to 2,000 Corrosive 2,000 to 10,000 Moderately Corrosive Greater than 10,000 Mildly Corrosive Based on the laboratory resistivity test results, the existing soils are anticipated to be severely corrosive to unprotected iron or steel pipe. A qualified corrosion engineer should review this data to determine the appropriate corrosion protection measures at the site. 4.3.9 Thermal Resistivity Evaluations As discussed previously, thermal resistivity testing was performed on two composite samples. Composite sample 1 was obtained by combining the top 5 feet of subgrade samples from Borings B-1 through B-3. Composite sample 2 was obtained by combining the top 5 feet of subgrade samples from Borings B-4 and B-5. Each of the composite samples was remolded to about 91 percent of the maximum dry density at near the optimum moisture content as determined from moisture-density relationship using standard effort (ASTM D698). The remolded samples were then tested for the thermal conductivity and a dry-out curve was prepared in accordance with ASTM D5334. The dry out curves for each of the remolded samples are presented in Appendix C. Proposed Solar Farm GEG Project No. 222-156 Parachute, Colorado December 17, 2022 14 | P a g e The thermal resistivity of the soils is impacted by the density and moisture content of the soils. The critical moisture content is the moisture content where the resistivity increases rapidly with decreasing water content. The density, sample moisture content, and critical moisture content estimated from the dry out curves are presented in Table 4-5. Table 4-5. Thermal Resistivity Samples Sample No. USCS Soil Class1 Sample2 Moisture Content Dry Density (pcf) Critical Moisture Content (%) Comp 1 CL Proctor 15.4 98.3 4.0 Comp 2 CL Proctor 18.0 90.8 6.8 1 CL= Lean Clay 2 Proctor= Sample remolded to about 91% of maximum dry density, and near the optimum moisture connect obtained from ASTM D698 Based on the test results and our understanding of the design and construction, the recommended thermal resistivity values are presented in Table 4-6. The recommended thermal resistivity values also consider the followings: 1. The cables will be installed within the upper four (4) feet of the overburden by open trench method or “trenchless” plowing installation method. For the open trench method, we anticipate that the excavated materials will be used to backfill the trench and cover the cables. 2. The bottom of the trench/installed cables will be soils with in-situ (moisture content and density) conditions. If open trench method is used, the trench backfilled will be overburden soils that are recompacted. The backfilled is recommended to be recompacted to at least 92 percent of the maximum dry density, and within 2 percent of the optimum moisture content as determined from ASTM D698. 3. The moisture content results determined from the laboratory testing indicate that the subsurface soils within the top four (4) feet of the overburden in Borings B-1 through B-3 have a moisture content of about 6.6 percent, which is about 2.6 percent wetter than the critical moisture content estimated from the thermal resistivity test of composite sample 1. The subsurface soils within the top four (4) feet of the overburden in Borings B-4 and B-5 have a moisture content of about 7.6 percent, which is about 0.8 percent wetter than the critical moisture content estimated from the thermal resistivity test of composite sample 2. Proposed Solar Farm GEG Project No. 222-156 Parachute, Colorado December 17, 2022 15 | P a g e 4. The backfill is within the moisture change zone, and the additional moisture from the compaction will evaporate and we anticipate the moisture content of the backfill materials will reduce and be similar to those measured from the native subgrade soils from borings. 5. We recommend the thermal resistivity estimated from the dry out curve using a moisture content of 6.6 percent in areas representative of B-1 through B-3, and 7.6 percent in areas representative of B-4 and B-5 to be used for the cable sizing and design. The estimated thermal resistivity values are presented in Table 4-6. Table 4-6. Recommended Design Thermal Resistivity Values Location Recommended Thermal Resistivity @ 6.6 or 7.6 percent Moisture Content (oC-cm/W) B-1 thru B-3 56 B-4 and B-5 75 6. An electrical or substation engineer should review the recommended thermal resistivity values and use them for the cable sizing and design. 5. FOUNDATION DESIGN RECOMMENDATIONS The site appears suitable for the proposed construction based upon geotechnical conditions encountered in the borings. Based on subsurface exploration and laboratory test results, and the geotechnical engineering analyses, driven piles are suitable for supporting the proposed solar panels. Trial installation and pull testing are recommended prior to construction to establish driving criteria and verify the capacity of piles. Expansive soils are present at the site and these soils will swell upon wetting and shrink when drying. Driven piles are anticipated to move with surrounding soils when moisture content changes unless the driven piles are installed deep enough to resist uplifting force due to swelling of native clay soils. Substation equipment can be supported on shallow slab/mat or footing foundations. Subgrade treatment may be required to reduce potential vertical rise (PVR) to a tolerable level. 5.1 Driven Post Foundations In our opinion, the solar development of the site is feasible from a geotechnical perspective. The soils encountered at the site are suitable for driven C-channel post foundations. The exact post Proposed Solar Farm GEG Project No. 222-156 Parachute, Colorado December 17, 2022 16 | P a g e sizes and embedment depths should be designed to resist the lateral, vertical downward, and pull-out loads. The recommended soil parameters for the design of the posts are presented below along with other discussions and considerations for design and construction of the direct-drive post foundations. 5.1.1 Foundation Soils Preparation The existing foundation soils could have potential vertical movement up to 2 inches due to moisture changes in the soil. The tolerance of the foundation movement on the driven post is not provided to us, however, if this vertical movement exceeds the tolerance of the structure, piles could be driven deeper or moisture conditioning of the existing foundation soils can be performed. When the foundation tolerance is available, GEG should be contacted to evaluate the suitable methods to mitigate the potential vertical movement due to moisture change of the foundation soils. 5.1.2 Direct-Drive Post Axial Capacity Vertical loads on the direct drive piles may be resisted by side friction and end bearing capacity of the subsurface soils. The upper 36 inches of soils should be ignored to account for the frost depth and swell/shrinkage. The recommended end bearing capacity, and side friction for vertical downward load and uplift loads for the direct-driven posts are presented in Table 5-1. Table 5-1. Recommended Direct-Drive Post Geotechnical Axial Capacity Parameters Depth Below Existing Grade (feet) 0 to 3 3 to 7 7 to 10 Below 10 Field Soil Type Clay Clay Clay Clay, Sand and Claystone Allowable End Bearing (psf)1,2 N/A 1,500 2,500 4,500 Allowable Side Friction, Downward (psf)1,2 N/A 250 400 550 Allowable Side Friction, Uplift (psf)1,2 N/A 200 320 440 1 Factor of safety of 3 applied for end bearing, 2 applied for side friction, downward, and 2.5 applied for uplift side friction 2 End bearing capacity should be estimated using the cross-sectional area of the post, side friction should be estimated using the “box” area of the post (height and width of the post). Proposed Solar Farm GEG Project No. 222-156 Parachute, Colorado December 17, 2022 17 | P a g e 5.1.3 Direct-Drive Post Lateral Capacity Lateral load capacity can also be calculated using the computer program LPILE. The soil parameters presented in Table 5-2 are recommended for use with the computer program LPILE to develop the soil models used to evaluate the direct-drive post response to lateral loading. Table 5-2 provides the estimated values associated with the soil types encountered in the borings. The shear strengths of the upper 36-inch of the soils is reduced to account for the frost depth and swell/shrinkage of native clays. Table 5-2. Recommended L-Pile Parameters Parameter Depth Below Existing Grade (feet) 0 to 3 3 to 7 7 to 10 Below 10 Field Soil Type Clay Clay Clay Clay, Sand and Claystone LPile Soil Model Stiff Clay Without Free Water Stiff Clay Without Free Water Stiff Clay Without Free Water Stiff Clay Without Free Water Effective Unit Wt. (pcf) 110 110 120 125 Cohesion (psf) 300 600 1000 1500 Friction Angle (o) 0 0 0 0 Strain Factor, ε50 0.02 0.01 0.01 0.007 Soil Modulus, k (pci) N/A N/A N/A N/A 5.1.4 Driveability Analysis The anticipated post size is unknown at the time of preparing this report. However, based on the encountered subsurface conditions and experience with similar projects, direct drive post installation to anticipated embedment depths (typically less than 10 feet) are feasible with low risk of refusal. Proposed Solar Farm GEG Project No. 222-156 Parachute, Colorado December 17, 2022 18 | P a g e 5.1.5 Predrilling If refusal is encountered from the direct drive post installation, predrilling may be required. Predrilling involves drilling a pilot hole at the post location with a smaller diameter hole, typically on the order of 4- to 6-inch diameter. The predrilled hole removes the materials that will refuse the post installations and provide space for the post to follow into the ground. The annular space from the pre-drilling may be backfilled with concrete, gravel or drilling spoils. The effectiveness of predrilling as an installation method should be evaluated during load testing. 5.1.6 Verification Load Testing Field load testing should include both lateral and vertical pullout testing. The verification load testing should be performed by using the piles and the driving equipment that are intended for the actual post installation. GEG should observe the field testing and based on the results of the tests the geotechnical parameters may be refined and adjusted. 5.2 Substation Equipment Foundations Substation equipment may be supported on shallow mat/slab foundations bearing on the native soils, moisture-conditioned and recompacted native soils, or structure fill. The existing subgrade soils have low to moderate swell potential. The potential vertical rise (PVR) is estimated to be on the order of 2 inches. Foundation subgrade treatment may be required depending on tolerance of foundations to the PVR. 5.2.1 Foundation Soils Preparation To minimize the impact from the swelling of the foundation soils, it is recommended to over- excavate the foundation soils, moisture-conditioned and recompacted according to Section 4.3.4 of this report, or replace with structural fill materials. Depending on the foundation type selected for the project, and the tolerance of the foundation type to potential vertical movement, the depth of foundation soils reconditioning or replacement with structural fill materials are recommended in Table 5-3. Table 5-3. Vertical Tolerance and Over-Excavation Depths Max. Vertical Movement Tolerance (inch) Depth of Moisture Conditioning of Existing Foundation Soils (ft)* Depth of Replacement with Structural Fill (ft)* 2.0 inch 0 0 1.0 inch 2 2 Proposed Solar Farm GEG Project No. 222-156 Parachute, Colorado December 17, 2022 19 | P a g e K v K v1 B 1 2B 2 * Measure from the bottom of foundations. Estimated moisture active zone of 10 feet from final finished grade. If structural fill materials are used to replace the existing swelling soils, drainage should be installed at at the bottom of the structural fill materials to prevent the accumulation of water in the structural fill soils and creating “bath-tub” condition. The drainage system should be daylighted or connect to the storm water system. 5.2.2 Equipment Pad and Footing Foundations The proposed equipment should be supported on shallow slab/mat foundations founded in/on the native subgrade soils (2-inch PVR is tolerable), or existing foundation soils that are moisture- conditioned and recompacted or structural fill materials. Shallow footings bearing in the moisture- conditioned existing foundation soils and structural fill/native subgrade materials could be proportioned using the bearing resistances of 1,500 psf and 2,000 psf, respectively. All footings should be supported a minimum of 36 inches below the final grade to provide protection against frost penetration. Total settlement is estimated to be on the order of 1 inch or less. Differential settlement is anticipated to be on the order of ½ to ¾ of the estimated total settlement. Lateral capacity of the footings may be derived from passive resistance along the vertical face of the footings, and friction between the bottom of the footings and the foundation soils. An allowable passive resistance using an equivalent fluid pressure of 120 pcf (F.O.S. of 2) may be used for the design. The friction coefficient of 0.27 may be used for moisture-conditioned foundation soils or native foundation soils, and 0.39 for structural fill materials. A factor of safety of 1.5 is recommended for the friction coefficient. We recommend upper 3 feet of the soils to be neglected in the passive resistance calculations. An allowable modulus of subgrade reaction, KV1, of 100 pounds per cubic inch may be used for design of mat foundations. KV1 refers to a 1-foot square plate and should be adjusted for actual foundation dimensions using the following equation (B is foundation width in feet): Proposed Solar Farm GEG Project No. 222-156 Parachute, Colorado December 17, 2022 20 | P a g e Foundation excavations should be observed by the geotechnical engineer or engineer’s representative. If the soil conditions encountered differ significantly from those presented in this report, supplemental recommendations will be required. Seismicity Based upon the geologic setting, subsurface soil conditions, liquefaction potential at this site is estimated to be low. The subsurface soil profiles correspond with Site Class D of the 2015 IBC. The intermediate values from 2015 IBC used to obtain the design parameters are provided below. Table 5-4. Design Acceleration for Short Periods SS Fa SMS (SMS = FaSs) SDS (SDS = 2/3 SMS) 0.267 1.587 0.423 0.282 S1 Fv SM1 (SM1 = FvS1) SD1 (SD1 = 2/3 SM1) 0.074 2.4 0.179 0.119 SS = The mapped spectral accelerations for short periods (U.S. Geological Survey Web Page, 2019) Fa = Site coefficient from Table 1613.5.3(1), 2015 IBC SMS = The maximum considered earthquake spectral response accelerations for short periods SDS = 5-percent damped design spectral response acceleration at short periods S1 = The mapped spectral accelerations for 1-second period (U.S. Geological Survey Web Page, 2019) Fv = Site coefficient from Table 1613.5.3(2), 2015 IBC SM1 = The maximum considered earthquake spectral response accelerations for 1-second period SD1 = 5-percent damped design spectral response acceleration at 1-second period 6. PAVEMENT THICKNESS RECOMMENDATIONS We understand that access roads will be constructed with aggregate surfacing. Two (2) type of access roads are planned, the temporary access road to support the construction vehicles and activities, and permanent access road for regular maintenance. The permanent access road may also be constructed as asphalt or concrete pavements. We anticipate that the traffic volumes during construction will be high and with heavy equipment. The traffic volumes for the permanent road will be light, with only occasional truck traffic. The gravel pavement that supporting the construction traffic will be maintained regularly depends on the road conditions. The pavement thickness design was completed generally following the 1993 AASHTO Guide for Design of Pavement Structures (AASHTO 1993). A serviceability loss of 1.0 were used in the gravel pavement design. We also assume that the pavement design life for the construction access road is 1 year, and the permanent road is 20 years. Proposed Solar Farm GEG Project No. 222-156 Parachute, Colorado December 17, 2022 21 | P a g e 6.1 Anticipated Subgrade and Subgrade Preparation Based on our field exploration and laboratory testing we anticipate the roadway subgrade soils will consist primarily of clayey soils. Laboratory test results indicate the soils are generally classified as A-6 using the AASHTO Classification system. Based on the engineering properties of the soil and locally accepted correlations, we estimate a CBR value of 3 for the pavement subgrade soils. Prior to placement of pavement structures the subgrade should be stripped of all topsoil and organics. The exposed subgrade should be prepared according to Section 4.3.1 of this report. Following initial preparation and prior to placement grading fill or pavement structures the subgrade should be evaluated by proof roll. Soft or otherwise unsuitable areas identified during the proof roll should be re-conditioned or the subgrade soils removed and replaced following section 4.3.1 of this report. 6.2 Aggregate Surfacing Pavement Thickness Design Traffic loading is not available for this project. GEG has assumed an Average Daily Traffic (ADT), truck percentage and estimated the 18-kip Equivalent Single Axle Loads (ESAL) as presented in Table 6-1. Based on the subgrade soils, anticipated traffic, and specified performance criteria we have provided the following aggregate-surfacing pavement thickness recommendations presented in Table 6-2. Table 6-1. Recommended Minimum Aggregate Roadway Thickness Road Type ADT Truck Percentage Design Life ESAL Temporary Haul Road- Subject to 18-Wheeler 100 - 20% Single Unit - 20% Combination Unit 1 Year 9,820 Temporary Construction Road- Earthwork Equipment Only 150 50% Single Unit Truck 1 Year 6,900 Permanent Access Road 10 10% Single Unit Truck 20 Year 2,000 Proposed Solar Farm GEG Project No. 222-156 Parachute, Colorado December 17, 2022 22 | P a g e Table 6-2. Recommended Minimum Aggregate Roadway Thickness Maximum Rutting Depth Temporary Haul Road Temporary Construction Road Permanent Access Road Native Subgrade Soils1 With geogrid2 Native Subgrade Soils1 With geogrid2 Native Subgrade Soils1 1.0 inch 19.0 - 18.0 - 10.0 1.5 inches 13 7.0 11.5 6.0 7.0 2.0 inches 10.0 6.0 8.5 6.0 6.0 1. Properly prepared subgrade in accordance with section 4.3 of this report. 2. We recommend geogrid including Tensar TX-160 or equivalent installed at the subgrade level, at the bottom of the gravel materials, to be used in the pavement section Aggregate-surfaced roads will require periodic maintenance to maintain the surface. Routine grading of the surface should be anticipated to remediate rutting and washboard surfaces. Periodic addition of base course material may be required throughout the life of the pavement. The performance of roads will be affected by the drainage provided. We recommend road surfaces and subgrades be provided with cross-slope of at least 1/2 percent to move water off pavement. The use of drainage ditches along the sides of the roads should be considered to drain the base course and improve road stability in wet conditions. 6.3 Asphalt and Concrete Pavement Thickness Design As discussed previously, the anticipated traffic for the proposed permanent access road is light. The following minimum pavement sections should be used for the permanent access road. Table 6-3. Recommended Minimum Pavement Sections Pavement Area Minimum Asphaltic Concrete (AC) Design Thickness Minimum Portland Cement Concrete (PCC) Design Thickness Permanent Access Road - 4.0 inches HMA - 6.0 inches Aggregate Base - 8.0 inches of Compacted Subgrade - 5.0 inches PCC - 6.0 inches Aggregate Base - 8.0 inches of Compacted Subgrade Proposed Solar Farm GEG Project No. 222-156 Parachute, Colorado December 17, 2022 23 | P a g e Pavement Materials 6.4.1 Base Course We recommend Coarse Aggregate Type Class 5 or 6 to be used for the gravel surfacing materials and aggregate base materials. The material should be placed in a uniform layer without segregation of size and compacted in loose lifts not to exceed 8-inches. The material should be compacted as recommended in Section 4.3.4 of this report. 6.4.2 Hot Mix Asphalt Hot mix asphalt materials, placement procedures, and testing should follow CDOT Standard Specifications for Road and Bridge Construction. We recommend PG 58-28 HMA binder with Grading S or SX aggregate, and gyration of 50. 6.4.3 Portland Cement Concrete The Portland Cement Concrete (PCC) shall conform to the requirements for Portland Cement Concrete Pavement, have a minimum 28-day flexural strength of at least 650 pounds per square inch (psi), and have a required minimum 28-day compressive strength of 4,000 psi. Drainage Proper drainage is of paramount importance in pavement performance. To avoid distress to pavement from wet, soft subgrade soils, we recommend the maintenance of good drainage away from all pavements. Possible water sources include storm runoff, irrigation of landscaping adjacent the pavement and localized groundwater seepage, among others. Joints in the pavement or at asphalt/concrete interfaces should be sealed. Any cracks or openings in the finished pavement surface should be sealed and/or repaired as quickly as possible. Pavement Maintenance Annual maintenance generally refers to crack filling and general surface sealers. We recommend implementation of an at least annual if not more frequent flatwork/pavement crack sealing program. This is very important to prevent surface water (especially from slow infiltration from sources such as snow melt and surface run-off) from entering cracks and wetting the subgrade. Any cracks or openings in the finished pavement surface should be sealed and/or repaired as quickly as possible. Proposed Solar Farm GEG Project No. 222-156 Parachute, Colorado December 17, 2022 24 | P a g e 7. LIMITATIONS The findings and recommendations presented in this report are based upon data obtained from borings, field observations, laboratory testing, our understanding of proposed construction, and other sources of information referenced in this report. It is possible that subsurface conditions may vary between or beyond the locations explored. If subsurface conditions are encountered during construction that differ from those described herein, we should be notified immediately in order that a review may be made and any supplemental recommendations provided. If the scope of the proposed construction, including the proposed loads or structural locations, changes from that described in this report, the conclusions and recommendations contained in this report are not considered valid unless the changes are reviewed, and the conclusions of this report are modified or approved in writing, by GEG. This report was prepared in in a manner consistent with that level of care and skill ordinarily exercised by other members of GEG’s profession practicing in the same locality, under similar conditions and at the date the services are provided. GEG makes no other representation, guarantee, or warranty, express or implied, regarding the services, communication (oral or written), report, opinion, or instrument of service provided. The scope of services for this subsurface exploration and geotechnical report did not include environmental assessments or evaluations regarding the presence or absence of wetlands or hazardous substances in the soil, surface water, or groundwater at this site. The recommendations provided in this report are based on the assumption that an adequate program of tests and observations will be conducted by GEG during the construction phase in order to evaluate compliance with our recommendations. The scope of our services did not include any environmental assessment or exploration for the presence of hazardous or toxic materials in the soil, surface water, groundwater or air, on, below or around this site. This report may be used only by the Client and the registered design professional in responsible charge and only for the purposes stated for this specific engagement within a reasonable time from its issuance, but in no event later than three (3) years from the date of the report. Proposed Solar Farm GEG Project No. 222-156 Parachute, Colorado December 17, 2022 Appendix A FIGURE A-1: SITE LOCATION PLAN FIGURE A-2: BORING LOCATION PLAN PROJECT NO.222-156 DRAWN:11/11/2022 DRAWN BY:XC CHECKED BY:HML FILE NAME: SITE LOCATION PLAN FIGURE A-1Proposed Solar Farm County Road 215 Parachute, Colorado222-156 Project Site PROJECT NO.222-156 DRAWN:11/11/2022 DRAWN BY:XC CHECKED BY:HML FILE NAME: BORING LOCATION PLAN FIGURE A-2Proposed Solar Farm County Road 215 Parachute, Colorado222-156 B-5 B-3 B-4 B-2 B-1 Proposed Solar Farm GEG Project No. 222-156 Parachute, Colorado December 17, 2022 Appendix B KEY TO BORING LOGS BORING LOGS Project Number:222-156 Proposed Solar Farm Lithology Symbols (see Boring Logs for complete descriptions) Claystone USCS Low Plasticity Clay USCS Low Plasticity Sandy Clay USCS Clayey Sand USCS Poorly-graded Sand with Silt Lab Test Standards Other Lab Test Abbreviations pH Soil pH (AASHTO T289-91) S Water-Soluble Sulfate Content (AASHTO T290-91, ASTM D4327) Chl Water-Soluble Chloride Content (AASHTO T291-91, ASTM D4327) S/C Swell/Consolidation (ASTM D4546) UCCS Unconfined Compressive Strength (ASTM D2166) R-Value Resistance R-Value (ASTM D2844) DS (C) Direct Shear cohesion (ASTM D3080) DS (phi) Direct Shear friction angle (ASTM D3080) Re Electrical Resistivity (AASHTO T288-91) PtL Point Load Strength Index (ASTM D5731)Notes Moisture Content ASTM D2216 Dry Density ASTM D7263 Sand/Fines Content ASTM D421, ASTM C136, ASTM D1140 Atterberg Limits ASTM D4318 AASHTO Class. AASHTO M145, ASTM D3282 USCS Class. ASTM D2487 (Fines = % Passing #200 Sieve Sand = % Passing #4 Sieve, but not passing #200 Sieve) Modified California Sampler (2.5 inch OD, 2.0 inch ID) Standard Penetration Test (ASTM D1586) Sample Types Legend for Symbols Used on Borehole Logs Project: 2. The Modified California sampler used to obtain samples is a 2.5-inch OD, 2.0-inch ID (1.95-inch ID with liners), split-barrel sampler with internal liners, as per ASTM D3550. Sampler is driven with a 140-pound hammer, dropped 30 inches per blow. 3. "ER" for the hammer is the Reported Calibrated Energy Transfer Ratio for that specific hammer, as provided by the drilling company. 1. "Penetration Resistance" on the Boring Logs refers to the uncorrected N value for SPT samples only, as per ASTM D1586. For samples obtained with a Modified California (MC) sampler, drive depth is 12 inches, and "Penetration Resistance" refers to the sum of all blows. Where blow counts were > 50 for the 3rd increment (SPT) or 2nd increment (MC), "Penetration Resistance" combines the last and 2nd-to-last blows and lengths; for other increments with > 50 blows, the blows for the last increment are reported. 35 31 20 16 S/C=3.2% @ 200 psf14.0 121.0 5-7-9 5-7-10 3-5 4-5-7 4-4 16 17 8 12 8 0.0 - 13.0 ft. LEAN CLAY, brown, moist, stiff to very stiff. 13.0 - 15.0 ft. POORLY GRADED SAND, with silt, tan, wet, loose. Bottom of Hole at 15.0 ft. Groundwater Levels: Logged By: J. Shekoski Final By: HML Symbol Depth Date Weather Notes: Sunny & Cool Inclination from Horiz.: Vertical 13.0 ft 10/21/22 - - - - Night Work: Boring Began: 10/21/2022 Boring Completed: 10/21/2022 Drilling Method(s): Solid-Stem Auger (4" OD) Driller: Vine Laboratories Drill Rig: CME 55 Rubber Track Hammer Type: Automatic (hydraulic), ER: 80% Total Depth: 15.0 ft Ground Elevation: Coordinates: Lat: 39.48339 Long: -108.10666 Location: Parachute, CO PAGE 1 of 1 Project Number:222-156 Atterberg Limits Boring No.:B-1 Li q u i d Li m i t Sa m p l e T y p e / Ad v a n c e m e n t M e t h o d Proposed Solar Farm Parachute, CO El e v a t i o n (f e e t ) De p t h (f e e t ) 5 10 15 Fi n e s C o n t e n t (% ) Pl a s t i c i t y In d e x Project Name: AASHTO & USCS Classifi- cations Field Notes and Other Lab Tests BO R I N G L O G 2 2 2 - 1 5 6 P A R A C H U T E S O L A R F A R M . G P J G E G B O R I N G L O G S T E M P L A T E . G D T G E G L I B R A R Y 9 - 3 - 2 1 . G L B 1 1 / 1 8 / 2 2 Mo i s t u r e Co n t e n t ( % ) Dr y D e n s i t y (p c f ) Blows per 6 in Pe n e t r a t i o n Re s i s t a n c e Li t h o l o g y Soil Samples Material Description 30 32 69.0 16 17 A-6 (8) CL S/C=2.5% @ 200 psf 6.6 12.6 123.1 12-13-13 3-8-8 4-4 4-5-7 10-12 26 16 8 12 22 0.0 - 5.0 ft. SANDY LEAN CLAY, tan, dry, very stiff. 5.0 - 14.0 ft. LEAN CLAY, brown, moist, stiff. 14.0 - 15.0 ft. CLAYSTONE, olive mottled with rust, decomposed, extremely soft. Bottom of Hole at 15.0 ft. Groundwater Levels:Not Observed Logged By: J. Shekoski Final By: HML Symbol Depth Date Weather Notes: Sunny & Cool Inclination from Horiz.: Vertical - - - - - - Night Work: Boring Began: 10/21/2022 Boring Completed: 10/21/2022 Drilling Method(s): Solid-Stem Auger (4" OD) Driller: Vine Laboratories Drill Rig: CME 55 Rubber Track Hammer Type: Automatic (hydraulic), ER: 80% Total Depth: 15.0 ft Ground Elevation: Coordinates: Lat: 39.48199 Long: -108.10465 Location: Parachute, CO PAGE 1 of 1 Project Number:222-156 Atterberg Limits Boring No.:B-2 Li q u i d Li m i t Sa m p l e T y p e / Ad v a n c e m e n t M e t h o d Proposed Solar Farm Parachute, CO El e v a t i o n (f e e t ) De p t h (f e e t ) 5 10 15 Fi n e s C o n t e n t (% ) Pl a s t i c i t y In d e x Project Name: AASHTO & USCS Classifi- cations Field Notes and Other Lab Tests BO R I N G L O G 2 2 2 - 1 5 6 P A R A C H U T E S O L A R F A R M . G P J G E G B O R I N G L O G S T E M P L A T E . G D T G E G L I B R A R Y 9 - 3 - 2 1 . G L B 1 1 / 1 8 / 2 2 Mo i s t u r e Co n t e n t ( % ) Dr y D e n s i t y (p c f ) Blows per 6 in Pe n e t r a t i o n Re s i s t a n c e Li t h o l o g y Soil Samples Material Description 32 34 64.0 56.0 18 19 A-6 (9) CL A-6 (7) CL S/C=3.5% @ 200 psf S/C=2.4% @ 200 psf 6.6 6.5 117.4 105.1 3-5 3-3 4-4-4 6-12 9-9-12 8 6 8 18 21 0.0 - 12.0 ft. SANDY LEAN CLAY, brown, moist, medium stiff to very stiff. 12.0 - 15.5 ft. CLAYEY SAND, tan, dry, medium dense. Bottom of Hole at 15.5 ft. Groundwater Levels:Not Observed Logged By: J. Shekoski Final By: HML Symbol Depth Date Weather Notes: Sunny & Cool Inclination from Horiz.: Vertical - - - - - - Night Work: Boring Began: 10/21/2022 Boring Completed: 10/21/2022 Drilling Method(s): Solid-Stem Auger (4" OD) Driller: Vine Laboratories Drill Rig: CME 55 Rubber Track Hammer Type: Automatic (hydraulic), ER: 80% Total Depth: 15.5 ft Ground Elevation: Coordinates: Lat: 39.4805 Long: -108.10202 Location: Parachute, CO PAGE 1 of 1 Project Number:222-156 Atterberg Limits Boring No.:B-3 Li q u i d Li m i t Sa m p l e T y p e / Ad v a n c e m e n t M e t h o d Proposed Solar Farm Parachute, CO El e v a t i o n (f e e t ) De p t h (f e e t ) 5 10 15 Fi n e s C o n t e n t (% ) Pl a s t i c i t y In d e x Project Name: AASHTO & USCS Classifi- cations Field Notes and Other Lab Tests BO R I N G L O G 2 2 2 - 1 5 6 P A R A C H U T E S O L A R F A R M . G P J G E G B O R I N G L O G S T E M P L A T E . G D T G E G L I B R A R Y 9 - 3 - 2 1 . G L B 1 1 / 1 8 / 2 2 Mo i s t u r e Co n t e n t ( % ) Dr y D e n s i t y (p c f ) Blows per 6 in Pe n e t r a t i o n Re s i s t a n c e Li t h o l o g y Soil Samples Material Description 3470.0 17 A-6 (10) CL S/C=0.2% @ 200 psf7.0 96.1 8-10-10 12-15 15-14-13 13-16 11-10-9 13-15 20 27 27 29 19 28 0.0 - 20.0 ft. SANDY LEAN CLAY, brown, dry, very stiff, contains calcium. Bottom of Hole at 20.0 ft. Groundwater Levels:Not Observed Logged By: J. Shekoski Final By: HML Symbol Depth Date Weather Notes: Sunny & Cool Inclination from Horiz.: Vertical - - - - - - Night Work: Boring Began: 10/21/2022 Boring Completed: 10/21/2022 Drilling Method(s): Solid-Stem Auger (4" OD) Driller: Vine Laboratories Drill Rig: CME 55 Rubber Track Hammer Type: Automatic (hydraulic), ER: 80% Total Depth: 20.0 ft Ground Elevation: Coordinates: Lat: 39.479 Long: -108.10219 Location: Parachute, CO PAGE 1 of 1 Project Number:222-156 Atterberg Limits Boring No.:B-4 Li q u i d Li m i t Sa m p l e T y p e / Ad v a n c e m e n t M e t h o d Proposed Solar Farm Parachute, CO El e v a t i o n (f e e t ) De p t h (f e e t ) 5 10 15 20 Fi n e s C o n t e n t (% ) Pl a s t i c i t y In d e x Project Name: AASHTO & USCS Classifi- cations Field Notes and Other Lab Tests BO R I N G L O G 2 2 2 - 1 5 6 P A R A C H U T E S O L A R F A R M . G P J G E G B O R I N G L O G S T E M P L A T E . G D T G E G L I B R A R Y 9 - 3 - 2 1 . G L B 1 1 / 1 8 / 2 2 Mo i s t u r e Co n t e n t ( % ) Dr y D e n s i t y (p c f ) Blows per 6 in Pe n e t r a t i o n Re s i s t a n c e Li t h o l o g y Soil Samples Material Description 3371.0 17 A-6 (10) CL S/C=-0.1% @ 200 psf7.6 97.610-12 11-15-12 10-8-11 10-8-8 12-18 10-10-12 22 27 19 16 30 22 0.0 - 20.5 ft. LEAN CLAY, with sand, brown, dry, very stiff, contains calcium. Bottom of Hole at 20.5 ft. Groundwater Levels:Not Observed Logged By: J. Shekoski Final By: HML Symbol Depth Date Weather Notes: Sunny & Cool Inclination from Horiz.: Vertical - - - - - - Night Work: Boring Began: 10/21/2022 Boring Completed: 10/21/2022 Drilling Method(s): Solid-Stem Auger (4" OD) Driller: Vine Laboratories Drill Rig: CME 55 Rubber Track Hammer Type: Automatic (hydraulic), ER: 80% Total Depth: 20.5 ft Ground Elevation: Coordinates: Lat: 39.47905 Long: -108.10193 Location: Parachute, CO PAGE 1 of 1 Project Number:222-156 Atterberg Limits Boring No.:B-5 Li q u i d Li m i t Sa m p l e T y p e / Ad v a n c e m e n t M e t h o d Proposed Solar Farm Parachute, CO El e v a t i o n (f e e t ) De p t h (f e e t ) 5 10 15 20 Fi n e s C o n t e n t (% ) Pl a s t i c i t y In d e x Project Name: AASHTO & USCS Classifi- cations Field Notes and Other Lab Tests BO R I N G L O G 2 2 2 - 1 5 6 P A R A C H U T E S O L A R F A R M . G P J G E G B O R I N G L O G S T E M P L A T E . G D T G E G L I B R A R Y 9 - 3 - 2 1 . G L B 1 1 / 1 8 / 2 2 Mo i s t u r e Co n t e n t ( % ) Dr y D e n s i t y (p c f ) Blows per 6 in Pe n e t r a t i o n Re s i s t a n c e Li t h o l o g y Soil Samples Material Description Proposed Solar Farm GEG Project No. 222-156 Parachute, Colorado December 17, 2022 Appendix C LABORATORY TEST RESULTS B-1 4.0~5.5 SPT 35 15 20 -- -- B-1 7.0~8.0 MC 14.0 121.0 31 15 16 3.2% @ 200 psf -- -- -- B-2 2.0~3.5 SPT 6.6 69.0 30 14 16 A-6(8) CL B-2 7.0~8.0 MC 12.6 123.1 32 15 17 2.5% @ 200 psf -- -- -- B-3 2.0~3.0 MC 6.6 117.4 64.0 32 14 18 3.5% @ 200 psf -- A-6(9) CL B-3 4.0~5.0 MC 6.5 105.1 56.0 34 15 19 2.4% @ 200 psf -- A-6(7) CL B-4 4.0~5.0 MC 7.0 96.1 70.0 34 17 17 0.2% @ 200 psf -- A-6(10) CL B-5 2.0~3.0 MC 7.6 97.6 71.0 33 16 17 -0.1% @ 200 psf -- A-6(10) CL Comp 1 0.0~5.0 BULK -- -- Comp 2 0.0~5.0 BULK -- -- Summary of Laboratory Test Results WaterSolubleSulfate(%) % Swell (+) /Consolidation (-)R-ValueDepth(ft) Atterberg Classification LL Project No:222-156 Fines< #200(%)AASHTOPISampleTypeBoringNo.Sand(%)USCSGravel> #4(%) Sample Location Gradation PSF NaturalDryDensity(pcf) NaturalMoistureContent(%) pH Unconf.Comp.Strength( ) Project Name:Proposed Solar Farm, Parachute, CO PL Page 1 of 1 Date: 2022-11-11Rev 09/18 0 10 20 30 40 50 60 70 0 20 40 60 80 100 PI 15 15 14 15 14 15 17 16 Passing #200 ATTERBERG LIMITS Date:11/11/2022 CH or OH LL PL 20 16 16 17 18 19 17 17 69 64 56 70 71 USCS Sample Description SANDY LEAN CLAY(CL) SANDY LEAN CLAY(CL) SANDY LEAN CLAY(CL) SANDY LEAN CLAY(CL) LEAN CLAY with SAND(CL) B-1 B-1 B-2 B-2 B-3 B-3 B-4 B-5 BOREHOLE DEPTH 4.0 7.0 2.0 7.0 2.0 4.0 4.0 2.0 35 31 30 32 32 34 34 33 AASHTO Class. Project No. 222-156 PL A S T I C I T Y I N D E X Drawn By: Lab Checked By: PM ML or OL "U" L I N E "A" L I N E CL o r O L CL-ML MH or OH LIQUID LIMIT A-6(8) A-6(9) A-6(7) A-6(10) A-6(10) Proposed Solar Farm Parachute, CO 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 0.0010.010.1110100 3/4 3/8 3 1002416 301 2006 10 501/2 U.S. SIEVE NUMBERS HYDROMETER Drawn By:Lab B-2 B-3 B-3 B-4 B-5 fine SAND mediumcoarsefine Checked By:PM LL 69.0 64.0 56.0 70.0 71.0 BOREHOLE DEPTH %Fines %Clay%Gravel USCS Classification AASHTO Classification PI 16 18 19 17 17 PL 14 14 15 17 16 %Silt%Sand GRAIN SIZE IN MILLIMETERS GRAVEL coarseCOBBLES CL CL CL CL CL 2.0 2.0 4.0 4.0 2.0 30 32 34 34 33 A-6(8) A-6(9) A-6(7) A-6(10) A-6(10) Proposed Solar Farm Parachute, CO Project No.222-156 PE R C E N T F I N E R B Y W E I G H T SIEVE ANALYSIS SILT OR CLAY Date:11/11/2022 U.S. SIEVE OPENING IN INCHES 1403420 406 601.5 8 14 Boring ID B-1' 7.0 10/20/2022 3.2 14 16.1 121 Project No. 222-156 Date:11/11/2022 Report By: XC Checked By: HML SWELL/ CONSOLIDATION TEST RESULTS Proposed Solar Farm Parachute, Colorado Natural Moisure Content (%) Dry Density (pcf) Saturated Moisture Content (%) FIGURE SWELL/CONSOLIDATION TEST - ASTM D 4546 C-4 Date Sampled Swell/ Consolidation (%) Sample Depth (ft) -2.0 0.0 2.0 4.0 0.01 0.1 1 10 Co n s o l i d a t i o n ( - ) / S w e l l ( + ) , % Applied Normal Pressure, ksf Boring ID B-2' 7.0 10/20/2022 2.5 12.6 14.9 123.1 Project No. 222-156 Date:11/11/2022 Report By: XC Checked By: HML SWELL/CONSOLIDATION TEST - ASTM D 4546 Saturated Moisture Content (%) Sample Depth (ft) Date Sampled Swell/ Consolidation (%) Natural Moisure Content (%) Dry Density (pcf) SWELL/ CONSOLIDATION TEST RESULTS FIGURE C-5Proposed Solar Farm Parachute, Colorado -2.0 0.0 2.0 4.0 0.01 0.1 1 10 Co n s o l i d a t i o n ( - ) / S w e l l ( + ) , % Applied Normal Pressure, ksf Boring ID B-3' 2.0 10/18/2022 3.5 6.6 19.6 117.4 Project No. 222-156 Date:11/11/2022 Report By: XC Checked By: HML SWELL/ CONSOLIDATION TEST RESULTS FIGURE C-6Proposed Solar Farm Parachute, Colorado Dry Density (pcf) Saturated Moisture Content (%) Sample Depth (ft) Date Sampled Swell/ Consolidation (%) Natural Moisure Content (%) SWELL/CONSOLIDATION TEST - ASTM D 4546 -3.0 -1.0 1.0 3.0 0.01 0.1 1 10 Co n s o l i d a t i o n ( - ) / S w e l l ( + ) , % Applied Normal Pressure, ksf Boring ID B-3' 4.0 10/18/2022 2.4 6.5 20.3 105.1 Project No. 222-156 Date:11/11/2022 Report By: XC Checked By: HML SWELL/ CONSOLIDATION TEST RESULTS FIGURE C-7Proposed Solar Farm Parachute, Colorado Dry Density (pcf) Saturated Moisture Content (%) Sample Depth (ft) Date Sampled Swell/ Consolidation (%) Natural Moisure Content (%) SWELL/CONSOLIDATION TEST - ASTM D 4546 -4.0 -2.0 0.0 2.0 4.0 0.01 0.1 1 Co n s o l i d a t i o n ( - ) / S w e l l ( + ) , % Applied Normal Pressure, ksf Boring ID B-4 4.0 10/18/2022 0.2 7 23.9 96.1 Project No. 222-156 Date:11/11/2022 Report By: XC Checked By: HML SWELL/ CONSOLIDATION TEST RESULTS FIGURE C-8Proposed Solar Farm Parachute, Colorado Dry Density (pcf) Saturated Moisture Content (%) Sample Depth (ft) Date Sampled Swell/ Consolidation (%) Natural Moisure Content (%) SWELL/CONSOLIDATION TEST - ASTM D 4546 -4.0 -3.0 -2.0 -1.0 0.0 0.01 0.1 1 Co n s o l i d a t i o n ( - ) / S w e l l ( + ) , % Applied Normal Pressure, ksf Boring ID B-5 2.0 10/18/2022 -0.1 7.6 22 97.6 Project No. 222-156 Date:11/11/2022 Report By: XC Checked By: HML SWELL/ CONSOLIDATION TEST RESULTS FIGURE C-9Proposed Solar Farm Parachute, Colorado Dry Density (pcf) Saturated Moisture Content (%) Sample Depth (ft) Date Sampled Swell/ Consolidation (%) Natural Moisure Content (%) SWELL/CONSOLIDATION TEST - ASTM D 4546 -2.0 -1.0 0.0 0.01 0.1 1 Co n s o l i d a t i o n ( - ) / S w e l l ( + ) , % Applied Normal Pressure, ksf Project No: Name: Location: 107.4 15.7 #10 #40 #200 ASTM Designation: Method: Rev.8-7-2020 11/03/22 5-lb, Manual 10/18/22 Joel Shekoski 11/02/22 Joel Shekoski Joel ShekoskiSampled By: Date: Date: Tested By: Date: Reviewed By: Hammer Type: PI: LL: PL: Atterberg (ASTM D - 4318) AASHTO Group Index: Specific Gravity: 4 inch ASTM D698 B #4 Gradation (ASTM D-422, D-136) Mold Size: DryPreparation Method: MOISTURE - DENSITY RELATIONSHIP USCS Group Name: AASHTO Group Symbol: CL COMP1 222-156 Parachute Solar Farm Soil Description: TAN TO BROWN CLAY WITH SAND Sample ID: Sample Location: Maximum Dry Density (pcf): Parachute, CO Optimum Moisture Content(%): B1, B2, B3 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 5.0 6.0 7.0 8.0 9.0 10.0 11.0 12.0 13.0 14.0 15.0 16.0 17.0 18.0 19.0 20.0 21.0 22.0 23.0 24.0 25.0 DR Y D E N S I T Y ( l b / f t ³ ) WATER CONTENT ( %) Zero Air Void Curves - Curves of 100% Saturation for Sp.G. Equal to: 2.60, 2.65, 2.70, 2.75, 2.80 Project No: Name: Location: 99.7 17.8 #10 #40 #200 ASTM Designation: Method: Rev.8-7-2020 11/03/22 5-lb, Manual 10/18/22 Joel Shekoski 11/02/22 Joel Shekoski Joel ShekoskiSampled By: Date: Date: Tested By: Date: Reviewed By: Hammer Type: PI: LL: PL: Atterberg (ASTM D - 4318) AASHTO Group Index: Specific Gravity: 4 inch ASTM D698 B #4 Gradation (ASTM D-422, D-136) Mold Size: DryPreparation Method: MOISTURE - DENSITY RELATIONSHIP USCS Group Name: AASHTO Group Symbol: CL COMP2 222-156 Parachute Solar Farm Soil Description: TAN TO BROWN CLAY WITH SAND Sample ID: Sample Location: Maximum Dry Density (pcf): Parachute, CO Optimum Moisture Content(%): B4, B5 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 5.0 6.0 7.0 8.0 9.0 10.0 11.0 12.0 13.0 14.0 15.0 16.0 17.0 18.0 19.0 20.0 21.0 22.0 23.0 24.0 25.0 DR Y D E N S I T Y ( l b / f t ³ ) WATER CONTENT ( %) Zero Air Void Curves - Curves of 100% Saturation for Sp.G. Equal to: 2.60, 2.65, 2.70, 2.75, 2.80