Res 2012-149 - Laserfiche WebLink

Home Browse Search

The UofHCL agrees to: 1) Objective #1 - Non - Native Plant Removal a) Remove non - native aquatic plants in association with fine sediment removal and TWR enhancement /restoration. Provide divers to conduct sediment control by first removing non - native aquatic plant species from the Project area to be worked that day. This removal will initially focus on Hydrilla verticillata and Hygrophila polysperma as these species are the most actively invasive. Prior to plant removal, the Project area will be fanned or sampled with appropriate gear to remove fountain darters and other native species. Divers will then remove, shake and bag non - native aquatic plants for disposal at the Texas State University Composting Center. Denuded areas will be planted with TWR or selected native species. b) Obtain TWR and native species from the United States Fish and Wildlife Service -San Marcos National Fish Hatchery Technology Center and /or Texas State University. Initial efforts for restoration of TWR or native vegetation will target planting of approximately 20 percent of the surface area restored. c) Monitor replanted areas monthly to evaluate the success rate and remove unwanted plant species from the planted areas and replant as needed to meet target area coverage. Conduct an annual river inventory to identify the presence and location of new non- native vegetation establishment. 2) Objective #2 — Sediment Removal a) Perform removal of targeted fine sediment utilizing hydrosuction at locations specified in the attached map following protocol outlined in the HCP. UofHCL's sediment removal efforts will target practical restoration effort that minimize potential negative impacts on the aquatic ecosystem and covered species habitats. These efforts will also provide supporting technical analysis of alternatives to the Sessom Creek sediment island ranging from no action to complete bar removal and the specific recommendation for action. b) Target for removal approximately 150 m2 of fine sediment in Spring Lake and follow with planting of TWR. c) Conduct hydrodynamic modeling to provide the best configuration of the channel upstream of the University Bridge that minimizes the sediment deposition in Sewell Park thus providing optimum TWR conditions downstream of Sessom Creek. UofHCL will expand the calibrated 2- dimensional hydraulic models provided by the SMOS for the entire San Marcos River to include the sediment rating curve that SMOS generated for Sessom Creek and rerun the hydrodynamic model for this section of river to evaluate sediment transport characteristics, bar formation at Sessom Creek and below the University Bridge under the existing channel configuration over a range of flow rates. In addition, UofHCL will evaluate alternative configurations of the existing sediment plug UotHCL Interlocal 2012 2