Optimal Prioritization of Best Management Practices Through a Simulation-Optimization Model to Sediment Load Reduction

Watershed management practices are as appropriate solutions to control nonpoint sources of pollution at watershed scale. Nevertheless, the best way to allocate limited resources is a challenge for watershed management efforts. Therefore, to achieve the most suitable strategies, manager requires the use of mathematical techniques to assign management practices priority. In this regards, in the present study, an optimization-based Decision Support Tool (DST) was used to assign the optimal combinations of management practices at the Taleghan Dam Watershed, Alborz Province, Iran.

To achieve the present research goals, Soil and Water Assessment Tool (SWAT) was applied to determine the sediment yield at outlet of the watershed under different combinations of management measures and was coupled with a genetic algorithm in MATLAB computer software, which provides as the optimization engine.

The results of optimization in the Taleghan Dam Watershed showed that implementation costs for 10% and 20% sediment reduction in optimal solution were obtained 110300$ and 235500$, respectively. The cost-effectiveness ratio of scenarios 10% and 20% sediment reduction obtained about 11030 and 11770.5 (dollars for 1% sediment reduction), respectively. The results also showed that filter strip and seeding are the most cost effective option for sediment load control. Conversely, the grade stabilization structure and detention pond are the least cost-effective option.

This tool is transferable to other watersheds and therefore, is one of the effective approaches of watershed management.