An Innovative Stormwater Best Management Practice Decision Support System for Quantifying and Optimizing Load Reductions and Costs in Los Angeles

摘要

Protecting environmental quality requires a comprehensive approach that heavily relieson our ability to confidently predict or forecast impacts, evaluate the ability of naturalsystems to absorb impacts, and determine the combination of options that will provide anacceptable level of protection and/or restoration. These forecasts, when accepted, canhelp stakeholders to understand the potential cost or implications of restoration optionsand guide the development of effective protection strategies that can mitigate and preventadverse impacts. Forecasts, which are typically based on combinations of modeling andanalysis, must be designed to be sensitive to changes in the watershed and to in-streamresponses. The difficulty with forecasts is that they are just predictions based on what weknow now and what we believe might happen in the future. That is why environmentalprotection studies emphasize rigorous science-based approaches that can buildconfidence in forecasts.Building on an extensive body of relevant studies in the Los Angeles region, includingmonitoring, model development, and regional model parameterization efforts, this studyis designed to develop and apply a Best Management Practice Decision Support System(BMPDSS) for the evaluation of alternative storm water best management practices(BMPs) and Low Impact Development (LID) methods. The system allows managers toevaluate the ability of various BMP scenarios to provide necessary flow volume andpollutant load reductions for Total Maximum Daily Load (TMDL) implementation andoptimizes the scenarios based on benefits and costs. The approach is designed to provideguidance for a public incentive plan for implementing onsite BMP/LID techniques.The framework developed in this study provides a technically defensible and repeatablebasis for evaluating quantitative measures associated with alternative BMPimplementation plans. The BMPDSS represents an advanced method for simulatingBMP processes and analyzing benefits (e.g., load reductions). Results of this studyprovide an interesting glimpse into the most relevant and economical BMPs for typicalland uses in the Los Angeles watershed.