|Shields Jr, Fletcher|
Submitted to: Federal Interagency Sedimentation Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: December 15, 1995
Publication Date: N/A
Interpretive Summary: Improved management of agricultural watersheds is a major goal of landowners and state and federal agricultural and environmental agencies. Large-scale flood control or water resources projects require that environmental evaluations be conducted prior to startup. Ecological projects which study baseline conditions can be combined with those that evaluate the success of individual items of work or construction efforts. When combined they can provide an effective feedback loop that can make a project more cost-effective and "fine tune" a project to achieve greater environmental benefits. In the Demonstration Erosion Control (DEC) Project in the Yazoo Basin, ecological study results allowed watershed planners to modify construction designs as the project proceeded. This allowed project managers to emphasize measures that created additional environmental benefits and alter measures that produced detrimental effects. Knowledge of this type of study use can benefit project managers and the public.
Technical Abstract: Improved management of agricultural watersheds is a major goal of state and federal agencies in the United States. Evaluation of a watershed's ecological well being is often mandated by a concerned public, regulatory agencies, or law. Ecological surveys provide an overall picture of plant and animal diversity and distribution in addition to watershed heterogeneity. A survey approach also documents landscape scale watershed conditions. Although surveys highlight problem subwatersheds, they are often too general to adequately evaluate success of individual management activities. Specific experiment approaches are more narrowly focused, providing ecological impact information for individual management techniques. Because specific experiment approaches evaluate at a higher resolution, they can detect ecological changes that may be masked in a survey approach. Specific experiments also provide information for "fine tuning" management techniques. A combined approach has been taken in evaluating the Demonstration Erosion Control (DEC) Project in the Yazoo Basin. Watershed surveys of water quality parameters are used to highlight problem subwatersheds and overall performance of erosion control measures. General survey data from fish, invertebrates and habitat are incorporated into biotic and ecological indices so that different watersheds can be compared. Individual management techniques such as field scale grade control pipes, grade control structures, and bank protection measures are evaluated and modified for improvement through specific experiments. Combining survey and specific evaluation investigations also documents cumulative contributions of individual projects to watershed-scale trends.