Res 2003-152 - Laserfiche WebLink

Home Browse Search

addition, the concrete abutments located along the riverbanks adjacent to the Rio Vista Dam will be removed (Enclosure 7, Photo 26). The 75 -foot approach walls will remain in place to provide bank stabilization. Silt accumulations above the dam will be removed by using the SVT prior to any Rio Vista Dam modifications to reduce soil disturbance and associated turbidity increases to habitat below the dam. In addition, the park area will be restored to a more natural setting through expansion of an existing wetland area along the diversion spillway, addition of topsoil with native grass plantings and removal of existing concrete bags (Enclosure 7, Photo 27). The USFWS, Texas Parks and Wildlife Department (TPVVD), local landowners, and the project sponsor (OMIT) have also expressed interest in removal of the Cummings Dam located downstream of the San Marcos and Blanco River confluence. The USFWS and TPWD have indicated that the Cummings Dam is negatively impacting water quality, native aquatic plant species and natural aquatic habitat within the San Marcos River. The Texas Commission on Environmental Quality (TCEQ) inspected the dam and determined that the structure is unsafe and has a faulty foundation. Feasibility of incorporating the Cummings Dam removal measure into the existing study will be determined in the Feasibility phase of the project. The modifications to the Rio Vista Dam and removal of the Cummings Dam would restore natural river flows, enhance aquatic fish habitat, de- fragment the river, provide migratory fish and mussel species access to upstream breeding, nursery, and feeding sites and promote recreational fishing, canoeing, and kayak use with the San Marcos River. Due to the possibility of cultural and historical significance associated with the structures, an assessment by a certified cultural resource specialist will be required prior to including these measures in the final restoration plan. (10) Education, Monitoring, & Recreational Enhancements: The City of San Marcos has proposed the use of a variety of education, monitoring and recreational enhancements within the project area. These amenities would not be included in the initial restoration project, but may be included as betterments following project completion. Potential betterments would be the full responsibility of the sponsor and must be consistent with law and policy regarding the USACE ecosystem restoration mission. Potential betterments could include installation of permanent river access points, creation of boardwalk structures, use of interpretive signs, and installation of trail materials. Permanent access points could be installed as betterments at several locations along the San Marcos River (Enclosure 7, Photos 19 -21). Identified sites are located within City Park (2), by the Hopkins Street Foot Bridge (1), within Dog Beach (1), at Bicentennial Park (1), within Rio Vista Park (2) and within Lucio Park (6). The access areas would not be greater than fifteen feet in length and width. They would serve as entryways and platforms that could be used by fishermen, canoeists, tubers, and swimmers. Some of the access points that promote recreational fishing would be created with wooden steps and an associated floating dock, whereas tuber /swimmer/boater access points would require ramps that could withstand heavy use. Other sites could use the placement of native stone aggregate or other similar construction material in a step -like formation. Native vegetation would also be planted in areas adjacent to the access area to discourage river users from entering the river in places other than the access points. 9