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<br /> <br />nitrogen impacts on water quality are typically ameliorated in wetland environments via <br />denitrification. <br />4.5 Present and Proposed Uses of Mitigation Area <br />Undisturbed riparian vegetated buffer strips along the river bank total about 27 acres and will <br />maintain or exceed the 100 ft County minimum set-back requirement. This standard is a best <br />management practice (BMP) to protect riparian habitat and filter contaminants from groundwater <br />and runoff discharging to river. Vegetative mapping was performed at the site recognizing IS <br />vegetation associations. Nine of the associations are dominated by introduced exotic species of <br />Russian olive and Tamarix (WestWater Engineering, 1998). The 33-acre island, located across <br />river channel in northern portion of project site, will not be mined of its approximately 490,000 <br />tons of reserve gravel. Also, approximately 4.8 acres of wetlands located along the south <br />perimeter of project site will remain undisturbed. <br />Riparian and natural wetlands, along with constructed wetlands and Texas Crossing, will be used <br />mainly for wildlife and fish habitat. Recreational use of site will remain restricted to public use <br />because private ownership of land. Livestock grazing will be excluded from the site during <br />mining and wetland reestablishment until the COE confirms that an acceptable mitigation goal was <br />attained. Once this mitigation goal is reached, the landowner may elect to continue grazing in <br />wetland mitigation area and remaining unmined areas upon completion of the project. <br />4.6 Jurisdictional Delineation <br />Site wetlands were delineated in accordance with COE standards in Summer 1998 (Appendix B, <br />MP-1 and MP-2). Site specific hydrological conditions are being assessed to refine wetland <br />delineation boundaries. Groundwater monitoring, initiated in Fall of 1998, is being conducted to <br />determine wetland hydrology. This baseline hydrologic information is required by the COE in <br />order to refine wetland boundaries previously delineated. The monitoring network includes an <br />array of shallow piezometers used to model temporal and spatial changes in water-table <br />configuration and response to irrigation water inputs <br />4.7 Present and Proposed Uses of All Adjacent Areas <br />Cattle grazing conducted by the Soaring Eagle Ranch will continue on land adjacent to project <br />site. The island in northern portion of site is also grazed by livestock and wildlife. Hunting rights <br />are leased through landowner and will continue in undisturbed areas and in reclaimed areas when <br />completed. <br />4-3 <br />