POWDER CREEK RESERVOIRAN INTEGRATED WATERSHED-RESERVOIR PLANNING APPROACH

摘要

The newly constructed Powder Creek Reservoir will serve primarily as a flood control and recreational facilityin an intensely agricultural region in northeast Nebraska. While the reservoir is not expected to have problems withpesticides, bacteria, or heavy metals; sediment and nutrient loadings are a concern for the long-term health and performanceof the reservoir. Experience in Nebraska and the region has shown that reservoirs with agricultural watersheds are typicallyprone to early eutrophication and loss of beneficial uses unless prudent non-point source pollution reduction measures areimplemented throughout the watershed and within the reservoir. Historically, planning and designing multi-purposereservoirs lacked a comprehensive/integrated approach at both the watershed and reservoir levels. A trend setting approachfor development of the Powder Creek Reservoir incorporated an integrated, community-based, watershed and reservoirplanning process prior to the final design of the project. As part of the planning process, Total Maximum Daily Loads(TMDLs) were developed for the Powder Creek Reservoir, with the required loading reductions to be achieved throughseveral measures within the watershed and the reservoir. Watershed management strategies included rehabilitation of severalaging grade stabilization structures functioning as sediment basins, enhancement of cost-share programs for most effectiveland treatment options, installation of new structural and non-structural BMPs, planned grazing, financial incentives forconversion of cultivated marginal lands to grass and pasture, post implementation monitoring, and information and educationprograms. The reservoir protection and prevention measures included high performance sediment basins, wetlands, andseveral means of shoreline erosion protection.