A Decision Support Tool Utilizing an HSPF Watershed Model Application for the Central Big Sioux River in Eastern South Dakota

摘要

A major challenge facing decision makers within the Central Big Sioux River Watershed is how to select the best combination of water quality management practices to implement among the many options available that result in the most cost-effective, achievable, and practical management strategy possible. This watershed is unique in South Dakota in that it contains municipalities with permitted stormwater discharges surrounded by highly productive agricultural lands. This provides an opportunity for the municipalities to contribute resources to help the rural communities implement management practices and for the rural communities to help the municipalities meet the water-quality goals identified in their permits at a potentially reduced cost. A watershed-scale, decision-support tool was developed to facilitate prioritization and placement of best management practices (BMPs) to achieve the needed reductions identified by the Total Maximum Daily Load (TMDL). The decision-support framework consists of a GIS system for site selection, Hydrologic Simulation Program - Fortran (HSPF) model application to simulate the transport and fate of pollutants, and a BMP database. The BMP database was developed by assigning costs and reduction efficiencies to commonly applied practices from literature. This decision-support framework will assist in the development of a custom implementation plan combining individual and/or a suite of BMPs that are simulated by applying the reduction efficiencies to the appropriate source loads represented in the HSPF model. The cost-effectiveness is calculated using the total costs and reductions achieved and from the application of the implementation plan. The decision-support tool will also include a cost-effectiveness optimization and water-quality trading component.