Clear Creek Watershed Flood Risk Management Habitat Assessments Using Habitat Evaluation Procedures (HEP): Analyses, Results and Documentation
ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS ENVIRONMENTAL LAB
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The cumulative effects of urban development along the Clear Creek southern Texas over the last 100 years has led to substantial increases in flooding. The flooding can be directly attributed to both the narrowing of the floodplain and the construction of buildings and infrastructure in the regions flood-prone areas. In 1999, the USACE Galveston District initiated a feasibility study to revise past efforts and formulate new solutions to address the Clear Creek problems and contacted the U.S. Army Engineer Research and Development Centers Environmental Laboratory ERDC-EL in 2003 for assistance. The District is preparing an Environmental Impact Statement EIS, as required under the tenets of the National Environmental Policy Act NEPA, to evaluate the impacts of proposed flood risk management measures in the watershed. As part of the process, a multi-agency evaluation team was established to 1 identify environmental issues and concerns 2 evaluate the significance of fish and wildlife resources and select resources 3 recommend and review environmental studies 4 evaluate potential impacts and 5 recommend and evaluate potential mitigation measures. Between 2003 and 2008, this team designed, calibrated, and applied a landscape-level community-based index model for the systems floodplain forests using standard Habitat Evaluation Procedures HEP. One hundred and one floodplain forest Average Annual Habitat Units AAHUs were lost due to the proposed flood risk management measures. Twelve individual mitigation plans were evaluated to offset the impacts detailed in the NED plan. The outputs for the various mitigation scenarios ranged from 9-180 AAHUs for the forests communities. The results of both the impact and mitigation assessments are provided herein. The intent of this document is to provide details of the HEP application for both the impact and the mitigation assessments for the Clear Creek project.
- Hydrology, Limnology and Potamology