A Site Scale Tool for Estimation of Pollutant Removal in Stormwater Best Management Practices

Abstract:

The objective of this research is to develop a module for design of Best Management Practices (BMPs) based on percent pollutant removal. The module is a part of the site scale integrated decision support tool (i-DSTss) that was developed for stormwater management. The current i-DSTss tool allows for design of BMPs based on flow reduction. The new water quality module extends that capability of the i-DSTss tool by adding new procedures for design of BMPs based on treatment performance. The water quality module can be used to assess treatment of colloid/total suspended solid (TSS) and dissolved pollutants. We classify BMPs into storage-based BMPs (e.g. pond) and infiltration-based BMPs (e.g. bioretention). In storage-based BMPs, TSS and dissolved pollutant are functions of decay rate and BMP size. In infiltration-based BMPs, we apply a modified colloid filtration theory for TSS that accounts for the effect of sedimentation, interception, and diffusion and BMP size and percent dissolved pollutant removal is a function of first order decay rate and BMP size. Several of the more complex stormwater tools require expertise to build and operate and other simple stormwater tools apply empirical approaches to estimate water quality. In contrast, the i-DSTss includes more detailed procedures compiled into simple to use tool with a graphical user interface. The i-DSTss and its component modules including water quality module are built on accessible platform and can be operated with a minimum skillset. It is based on readily available data and provides a comparative analysis among various scenarios for BMP design. To enhance usability of the tool by a broad range of users, the tool is designed to be flexible allowing user interaction through a graphical user interface.