Optimal Location of Sediment-Trapping Best Management Practices for Nonpoint Source Load Management

Abstract

Selecting approaches to managing nonpoint source pollution is challenging due to the complex generation and transport processes that influence the quantity of pollutant that eventually reaches a receiving water. Pollutant transport is influenced by land surface characteristics along the transport path, and these effects should be considered when optimizing management approaches for nonpoint source pollution. A fully distributed sediment-generation and transport watershed model is presented within an optimization framework to enable the development of spatially precise solutions to sediment-trapping best management practice (BMP) placement at the watershed scale. To focus on the BMP-siting problem, a stylized representation of a BMP is assumed to be capable of reducing sediment mass by a fixed fraction, and optimal arrangements of this assumed BMP type are developed with a genetic algorithm. The results suggest that the optimal location for sediment mass reduction is not necessarily at locations of only high mass generation or at locations of only high transport capacity. The results also suggest that there are efficient locations for management that produce a relatively large reduction in storm sediment load.