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(\ () 1 7 0 (}'Vet/and Mitigation A- 11 The total wetland impact of Monitor Sites, assuming they are all ultimately activated, is 0.44 acres. This impact will be mitigated at the Wetlands Mitigation Site before the project commences operation. A "mitigation bank" will therefore already be in place for the day the sites are activated. If the sites are never constructed, then the mitigation will have been excess. A.3.2.4 Access impacts Construction road access will temporarily affect 0.15 acres of jurisdictional wetlands. This impact will be mitigated by use of wood chips for road bedding, keeping turn- arounds out of wetland areas, and reclaiming and restoring the areas after construction is complete. Construction access will typically be needed for only a few days or weeks, so the impact will be of very short duration. A.3.3 The Wetland Mitigation Site In NEPA consultation, the Corps, EPA and USFWS indicated the need for a wetland mitigation site to replace wetlands unavoidably lost through the bank stabilization process. These agencies either recommended or approved use of the Corps' "WET-2" computer model to identify lost wetland functions and values, and to help design a mitigation site that would compensate for these losses. HDR performed the requested analysis in 1990. Data input was based upon field delineations of riparian wetlands conducted during 1989. The model tabulated functions and values for the types of wetlands observed on the river, and allowed comparisons for various mitigation site designs. Model results are reported in the FEIS, and are available upon request. Ultimately, a mitigation site composed of 27% low prairie, 9% sedge marsh, 18% willow emergent marsh, and 45% open/emergent marsh was recommended and approved in the NEP A process. This balance replaced functions and values that would potentially be lost by stabilizing banks of the Uncompahgre. The selected mitigation site is within the existing Uncompahgre River floodplain, on land already owned by the Applicants. It is adjacent to Bank Protection Sites 47, 48 and 49, which between them represent about 25% of all stabilization-related wetland impacts. The site will be monitored throughout the life of the project. Water supply will be from existing groundwater, with supplemental supplies available from the Uncompahgre River or the project tailrace. Additional information is included in the EIS. A plan view of the mitigation site is included in the attached Figure 1. The proposed site was 12 acres in size, originally with 8 acres devoted to compensating for stabilization impacts. The site was approved in Interior's Record of Decision issued in December, 1991. As bank stabilization impacts are now known to be much less than 8 acres, the excess will be allocated to indirect (widening) impacts. Thus 4 acres will be devoted to mitigating canal-bank wetland losses, 1.4 acres to direct stabilization impacts, and 6.6 acres to indirect impacts. AS Lateral Hydropower Project July 2000 ." :~ <.1' ,.