The URL can be used to link to this page

Home My WebLink About1.21 Impact Analysis19. IMPACT ANALYSIS Introduction The Cerise Gravel Pit will have an impact on the adjacent properties. In order to minimize and mitigate this impact, United has developed a mining and reclamation plans that use concurrent reclamation and limited advance. Concurrent reclamation is the act of immediately backfilling, grading, and revegetating areas once mining has been completed in areas. Limited advance is the technique of not disturbing natural ground until the natural resource beneath is absolutely needed. Resolution 2011-44 attempted to mitigate impacts using large berms and piles to obscure operations from the neighbors. To generate the material needed to build these piles, large areas of the property were disturbed before they were to be mined. The new plan proposed in this application does the opposite: limiting berm and stockpile size to that needs to store material from the smallest practical excavation area. Adjacent Land Use The surrounding properties are almost all zoned Rural according to Garfield County GIS data. Cerise Property Rortrri 011. . Area Zoning 54 r r 1. Rab' HI1€kys To the east and west are active gravel mines. North of the property are several homes. To the south lies the Roaring Fork River and Colorado Highway 82, with a residential housing development south of that. Site Features The Cerise Mine site is located on a plateau that sits high above any FEMA floodplain as well as Crystal Creek, a stream that runs along the western edge of the site. The Basin Ditch runs along the north edge of the Cerise Mine, but it has been excluded from the Cerise Mine permit area so the ditch will not be affected by the mining operations and will remain operational where it is currently located. Details regarding the existing vegetation at the Cerise Gravel site is provided in the Natural Habitat Statement from Resolution 2011-44 (See Section 27: Appendices). The groundwater elevation on the Cerise Mine site was measured at over 90 feet below the ground surface. The mine plan anticipates mining to 100 feet deep, but will stay at least two feet above ground water. United will visually monitor for groundwater during mining to make sure all mining remains above the groundwater elevation. Climate data for the Cerise Mine site is assumed to be similar to that of the Glenwood Springs #2 (053359) weather station. The Western Regional Climate Center tracks temperature extremes and precipitation data for this station. The table on the following page includes data that was collected between September 1, 1893 and August 31, 2009. GLENWOOD SPRINGS #2, COLORADO (053359) Period of Record Monthly Climate Summary Period of Record: 9/1/1893 to 8/31/2009 55 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual Average Max. Temperature (F) 36.9 42.6 51.5 61.6 72.1 82.3 88.6 86.1 78.3 66.3 50.0 38.1 62.8 Average Min. Temperature (F) 11.7 16.7 24.5 31.2 38.4 44.2 50.8 49.6 41.9 32.0 22.4 13.6 31.4 Average Total Precipitation (in.) 1.47 1.25 1.42 1.60 1.42 1.10 1.23 1.48 1.60 1.46 1.15 1.29 16.47 55 Average Total Snow 18.0 11.2 6.7 1.9 0.3 0.0 0.0 0.0 0.0 1.1 5.3 I5.1 59.6 Fall (in.) Average Snow Depth (in.) 5 3 0 0 0 0 0 0 0 0 0 3 1 Percent of passible observations for period of record. Max. Temp.: 90.5% ; Min. Temp.: 90.3%; Precipitation: 91.7°'o; Snowfall: 87.7%; Snow Depth: 4I.6° 0 Check Station Metadata or Metadata graphics for more detail about data completeness. Source: Western Regional Climate Center, wrcc@dri.edu Soil Characteristics According to the mapping available on the Natural Resources Conservation Service's (NRCS) website(http://websoilsurvey.nrcs.usda.gov/), the soils found on the Cerise Mine property include: Almy loam, 1 to 12 percent slopes Empedrado loam, 2 to 6 percent slopes Fluvaquents, 0 to 10 percent slopes For more information about the soils, please see the Soils Information in Section 16 of the application. Geology and Hazard There are no known potential existing or potential geologic hazards associated with the Cerise Mine. The Cerise Mine site is north of the Roaring Fork River on an undifferentiated terrace and pediment alluvial deposit Holocene to Pleistocene in age (1.8 mya to present). The deposit is composed of various amounts of cobbles, gravels, sands, silts, and clays. The site subsurface conditions were investigated through an exploratory drilling program conducted by Deere and Ault and EnviroGroup. The results of exploratory borings indicate that bedrock was not encountered to the maximum depth explored (119') within the proposed mine Iimit. From a geotechnical standpoint, sand and gravel will form most of the mine slope. These soils are generally strong and stable, particularly when no groundwater is present, as will be the case at Cerise Mine. Minor amounts of clay will lie at the ground surface and locally as lenses within the sand and gravel. For more information, please see the Stability Analysis Letter and Boring Logs found in Section 15: Geotechnical Information. Effect on Existing Water Supply and Adequacy of Supply United Companies has determined that 25 ac -ft of water will be needed by the Cerise Gravel Pit each year to supply processing and dust control operations. This water will come from junior, undecreed water in the Basin Ditch during "free river" conditions. In the event that ditch conditions no longer support said "free river" water, United has a lease in place with the Basin 56 Water Conservancy District to augment any out -of -priority depletions. See the United-BWCD agreement in Section 27. Effect on Groundwater and Aquifer Recharge Areas The Cerise mining operation will be conducted above the water table. Consequently, the mine is projected to have negligible impacts on groundwater resources in the area. The site hydrogeology indicates that no existing permitted private wells would be significantly affected by the mine operation. All mining and processing area surface flows will be directed to the pit, which wilI allow for infiltration of the water. Discharge to the neighboring waterbody (Crystal Creek) is not needed as the pit will be large enough to capture and detain these flows. The Cerise Mine site is located outside of the floodplain and floodway of the Roaring Fork River. The mine site is separate from the river and floodplain by both Highway 82 and a berm that is over 100 feet higher than the Roaring Fork River Base Flood Elevation (BFE) based on the FEMA Flood Insurance Rate Mate for Garfield County, CO (unincorporated areas) Community Panel 080205 1880B. Crystal Creek is a smaller stream that runs along the western border of the mining site. This creek is not included in the FEMA mapping for the area. However, the river is over 25 feet lower than any adjacent mining activity and over 60 feet from the closest grading extents. There will be no mining in the floodplain of the creek, which has a 100 -year discharge of approximately 300 cfs. The Cerise Mine is not in close proximity to a public sewer system. Therefore, the restroom facilities in the office will be portable toilets will be provided on the site for employees to use. At least one portable toilets will be on site at all time, and more may be added during the construction season if needed. Environmental Effects 1. Determination of the long term and short term effect on flora and fauna. There will be no significant long term or short term effect on flora and fauna as there is no Federally designated critical habitat for vegetative or wildlife species in the Cerise Mine Permit area. 2. Determination of the effect on designated environmental resources. including critical wildlife habitat. 3. Impacts on wildlife and domestic animals through creation of hazardous attractions. alteration of existing native vegetation, blockade of migration routes, use patterns or other disruptions. The Cerise Mine will have a minimal effect on environmental resources due to the fact that the area of disturbance is currently used for agricultural purposes and therefore does not provide optimal wildlife habitat. No hazardous attractions will be created on the mine site, the existing vegetation will eventually be 57 replaced at the time of reclamation, and no significant migration routes will be disrupted by the mine. 4. Evaluation of any potential radiation hazard that may have been identified by the State or County Health Departments. There are no potential radiation hazards associated with the Cerise Mine. Nuisance - Visual Please see the revised visual analysis by MIG. Nuiscance - Noise Please see the revised noise analysis that is attached in this section. Nuisance - Air Quality Please see the attached Colorado Department of Public Health and the Environment Air Pollution Control Division permits for the Cerise Gravel Pit along with the Fugitive Dust Control Plan.