2018-03-29_REVISION - M1977534 - Laserfiche WebLink

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Revegetation Assessment Guanella Reservoir Clear Creek County,Colorado was added per the reclamation plan. The reclaimed area of Phase II consists of a mostly level terrace at approximately the same elevation as the adjacent terrace to the south that was not disturbed by mining (U.S.Geological Survey 1958). Table 1. High altitude, low growth seed mix. Grasses P (%)of 1bx Ephraim Crested Wheatgrass 30 Dwarf Perennial Ryegrass 25 SR3200 Blue Fescue 20 Reubens Canada Bluegrass 15 Chewings Fescue 10 Source:DMG 112 Permit#M-77-534-TR1 On the western edge of Phase II, including the project area,th terrace shallowly slopes down to the parking lot below the reservoir dam (outside of the Phase II reclaimed area). The unvegetated salt- crusted area occurs at the bottom of the slope and extends about one-third up the slope. Patches of vegetation occur around the unvegetated area. On March 2, 2018, Denise Larson with ERO visited the project area to assess existing conditions and take soil samples (2018 site visit). Most of the project area is unvegetated with a salt crust on the surface. Crested wheatgrass (Agropyron cristatum)and kochia (Bassia scoparia)were observed around the salt- crusted areas and in the Phase II areas to the east. In the September 2017 inspection report, perennial ryegrass and Canada bluegrass was also observed. In nearby areas of native vegetation, western wheatgrass(Pascopyrum smithii)and a brome(Bromus sp.)were common. A soil sample was taken in the project area (S2). To compare the soils in the unvegetated project area to vegetated portions of the reclaimed Phase II, another soil sample(Si) was taken. Both samples followed Colorado State University Soil, Water,and Plant Testing Laboratories (CSU Soil Testing Lab) Instructions (CSU 2018)except that only the top 3 or 4 inches were sampled because the soil below that depth was frozen. The soil samples were submitted to the CSU Soil Testing Lab for routine sampling(pH, salts, organic matter, NO3, P, K,Zn, Fe, Cu, Mn, B lime,and texture estimates) plus Sodium Evaluation (SAR). Results The results from the CSU Soil Testing Lab show that the soils in the project area (S1) are very high in salts and high in sodium,which would severely reduce plant growth (Appendix A). The pH is suitable for plant growth, and the organic matter amount is more than 2 percent(2.6 percent),which is suitable for growing native vegetation (Munshower 1993). Where vegetation is growing(S2),the pH and salt levels in the soil are acceptable, although the pH at 8.1 is basic and may be unsuitable for some plant species. 3