2011-06-21_APPLICATION CORRESPONDENCE - C2010088

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Corey Heaps CAM Colorado LLC June 21, 2011 Page 15 mapped on the ground for the current survey, was previously mapped on the area during the 1978 NRCS survey, and it was also mapped on the same parcel of ground for an earlier 1980 detailed soil survey for Gary Energy which was reviewed and accepted without critical comment by the then Colorado Mining and Land Reclamation Division (CMLRD). The Irrigated Wetlands vegetation type is part of the 'Bi' soils classification as shown on Map -06. Please see revised Map -06. Division Response: Response accepted. 22. There is a Torrifluvents ( "RW ") map unit designation on the Soils Map (Map 6), within the northwest portion of the permit area within the Irrigated Wetlands vegetation type, but it is not clear whether the designation is intended to apply to a narrow corridor of presumed riparian vegetation along Loma Drain, or to the larger area of wetland vegetation. Please clarify and revise the map as appropriate, along with related text in the narrative of Section 2.04.9 and Exhibit 7. Note that the band of apparent riparian vegetation along Loma Drain as shown on the Vegetation Map (Map 3) does not correspond to the presumed riparian zone indicated on Map 6. Please explain the apparent discrepancy and revise whichever map is not correct. Also, please refer to concerns in Item 3 regarding the version of the NRCS soil survey used as the basis for the Exhibit 6 mapping. The current NRCS soil mapping (USDA Web Soil Survey) shows Ustifluvents, 0 to 2 percent slopes, occurring along the riparian zone within the incised Reed Wash drainage, rather than Torrifluvents. CAM Response: 'RW' designation was inadvertently placed on the Irrigated wetlands area and has been removed. Please see revised Map -06. In addition, RW is now correctly shown in Loma Drain. Division Response: Response accepted. 23. Data from the three soil sample sites indicates that the surface 18" of the Billings soil at Sample #1 is a considerably better growth medium (lower pH, and much lower EC and SAR), as compared to the other two sample sites for the same soil unit. In. fact, the soil horizon between 6" and 18" depth at Site 1 appears to be better quality growth medium than the surface 6" at Sample Sites #2 and #3. The soil salvage plan. appears to be based on the characteristics of the soil at Sample Sites #2 and #3. Are Sites #2 and #3 believed to be more characteristic of the Billings soil areas that would be disturbed by site construction than Site #1? To what extent would map unit boundaries and interpretations be different if the Web Soil Survey map units were the basis of the mapping rather than the previous NRCS survey map (e.g. would Site #1 likely fall within a separate map unit and be subject to a different salvage plan than Site #2 and #3)? Please address these questions and discuss how the salvage plan proposed or amended will maximize salvage of the best quality soil materials, to ensure the best opportunity for successful vegetation establishment.