Blog 7

Optimal Location of Infiltration-Based Best Management Practices for Storm Water Management
By Cristina Perez-Pedini, James F. Limbrunner, and Richard M. Vogel

Summary

The purpose of this study was to introduce a methodology to determine the optimal number and location of infiltration-based BMPs on a watershed to reduce peak flow flood flows at the watershed outlet (Perez-Pedini 441). Although the research can be applied to numerous watersheds, the Aberjona River watershed northwest of Boston, Massachusetts was the focus of this study. This small highly urban catchment was modeled in a spreadsheet and optimized using a genetic algorithm (GA) to determine areas within the watershed where the application of infiltration-based BMPs would be most effective in decreasing flood flows at the catchment outlet (Perez-Pedini 442). A distributed, event-based hydrologic model, along with the SCS curve number method, was employed to determine the runoff and infiltration for each of the 4,533 hydrologic response units (HRUs)

During the optimization process, the overall goal was to locate the HRUs which, if BMPs were applied, would lead to a maximum reduction in peak stream flow at the watershed outlet (Perez-Pedini 444). The end result revealed that the optimal location of the BMPs was a complex function of HRU characteristics and locations. The authors summarize the results by creating a Pareto frontier depicting the number of BMPs, which is synonymous to the project cost, and peak flow reduction.


Discussion

The research conducted by Perez-Pedini has great applicability because (1) it can be applied to nearly any watershed; (2) the analysis could be used to inform policy decisions regarding future storm water management investments; (3) the optimal number of BMPs can be constructed in stages as funds become available, while still achieving optimal reduction during each stage (i.e. When only a few BMPs are located, their optimal locations are subsets of the optimal locations of a much larger set of optimal BMPs.).