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Gulf South Research Corporation

Featured Project
The Continuing Authorities Program (CAP) and Section 206 of the Water Resources Development Act of 1996 authorize the Fort Worth District to participate in the development and implementation of projects to restore terrestrial and aquatic habitats that have been significantly disturbed, degraded, or altered.  GSRC was tasked by the Fort Worth District to complete the feasibility study for the proposed aquatic ecosystem restoration project along the San Marcos River in San Marcos, Texas.  The project, which will be cost-shared with the City of San Marcos, includes plan formulation and the development of an Integrated Detailed Project Report and Environmental Assessment (DPR/EA) for the aquatic ecosystem restoration project.

The upper San Marcos River is a unique ecosystem. Continuous spring flows, exceptional water quality, moderate temperatures, and a long growing season have contributed to the development of a highly diverse macrophyte community.  Two Federally listed species, Texas wild rice (Zizania texana) and San Marcos salamander (Eurycea nana), are endemic to the San Marcos River in the project area.  The construction of dams and diversions along the river hassubstantially altered hydrology, the introduction of nonnative plants and animals has resulted in increased competition with natives and changes in the habitat structure, urbanization has surrounded much of the watershed in the project area, and recreational tubing and canoeing have destabilized banks in many locations.  GSRC coordinated with the City of San Marcos, the U.S. Fish and Wildlife Service, Texas Parks and Wildlife Department, and the River Systems Institute to develop measures to remove exotic species (e.g., elephant ear [Colocasia esculenta]), reduce sediment loading, increase the cover of riparian woodlands, create wetlands, control recreational access, and restore a more natural hydrology to the river by removing existing dams.  GSRC collected baseline data describing the existing suitability of habitats using Habitat Evaluations Procedures (HEP).  GSRC developed costs for all restoration measures and conducted an Incremental Cost Analysis using IWR-Plan to evaluate all reasonable alternatives and select the best-buy plans and provide guidance on selecting the Recommended Plan.  Following the new planning paradigm for Civil Works projects (3x3x3 rule), GSRC has completed the Alternative Formulations Briefing report for the Fort Worth District and is preparing the DPR/EA.  This project is 80 percent complete.