Rio Grande - Alamosa River Watershed Restoration_Application

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e Water Supply Reserve Account - Grant Application Form Form Revised May 2007 River. The goal of the overall project is to develop a river system that will bring back and maintain a healthy ecological system with a minimal amount of water. The river restoration effort is just one part of a comprehensive effort to tackle many problems facing the Alamosa River. The Riverkeepers are working towards the reestablishment of in-stream flow and, as a complementary structural project, this proposed phase of river restoration will literally lay the groundwork to receive the water and deliver it most efficiently. The re-shaping and in-stream structures will improve the water system by delivering the water supply to agricultural users more efficiently. With the river stabilized, a small amount of water will be utilized most efficiently, maintaining the life of the river with the least amount of water necessary. Because the water will be contained in a more natural channel system, surface evaporation will be reduced due to the reduction of the width-depth ratio of the channel and of erosion and sediment. By encouraging regrowth of bank vegetation, the water will also be cooled. Adding water to the local system will help to recharge the aquifer significantly. The many wells that had to be redrilled in 2002 are indicative of the need to sustain the aquifer through a supportive water system. - 7. Please provide a brief narrative of any related or relevant previous studies. The scope of the present proposed Alamosa River restoration project (second phase) encompasses the remaining 2.8-mile section within the 5.5-mile reach of the Alamosa River-Gunbarrel Road to County Road 10- prioritized for stream bank restoration in the 2005 Alamosa River Watershed Restoration Master Plan as Tier 1., Project Type no. 1. The Master Plan (some 450 pages) summarizes current environmental conditions and develops solutions for identified problems in the Alamosa River basin that will lead to a healthier watershed. The incentive for the Master Plan was provided by a legal settlement over potential injuries caused by the Summitville Mine. That settlement also provided funding for implementation of some of the restoration projects described in the Master Plan. The scope of the Master Plan includes the entire watershed, except for the Summitville Mine, which is a Superfund site. This extensive plan was produced by MWH for the Summitville Natural Resource Damage Trustees, including CDPHE, CO Attorney General, CO Dept. of Natural Resources, US Bureau of Land Management, US Fish & Wildlife Service, and US Forest Service. The plan required broad-reaching public involvement and acceptance and was heavily scrutinized by the above-mentioned organizations. As in the response to question B. 3., the proposed second phase of the restoration project continues the restoration work on the Alamosa River performed in 2004-6. The measures in the current project phase will implement techniques successful in the previous phase. The proposed in-stream and bank structures have been demonstrated to be highly effective in stabilizing the river in the restoration of the channel downstream of Gunbarrel Road. The spring runoff following the 2004 restoration efforts was substantially above normal due to a snowpack that was 25-30% above average resulting in an extended high flow well above bankfull conditions. Bank erosion was limited to what is normal during the "settle-in" period following restoration. The 2005 runoff season was just below average bankfull. In 1997 Dave Rosgen completed an assessment and conceptual plan for the reach from Terrace Reservoir to Hwy. 285, and in 2001 Black Creek Hydrology began a detailed design study for the 5.5 mile overall reach. Using a "fluvial geomorphological approach," the proposed work will reduce sediment introduction into the river system by interrupting the compounding erosional effects that continue to diminish banks. These earlier river assessment and monitoring efforts found that the project reach of phase two contains approximately 12,500 sq. ft. of eroding bank surface on approximately one half mile of stream bank distributed over the 2.8-mile proposed reach. Monitoring of cross sections has shown that some of these-banks have experienced lateral erosion bank loss of eight to nine feet over the past two runoff seasons. This loss of bank will likely create more erosion on an additional .5 mile of stream if not addressed. . 17