2023-2024 Executive Summary
Stormwater BMPs (best management practices) are a disparate collection of engineered solutions, landscaping modifications and other strategies for managing how water runs off the land during both dry and wet weather. Although Southern California’s stormwater management community is expected to spend billions of dollars on stormwater BMPs in the coming decades to reduce contamination levels in runoff and better control flows, relatively little is known about how to optimize their design, placement and long-term effectiveness. SCCWRP is developing BMP strategies and tools intended to bring clarity and confidence to the science of stormwater management. SCCWRP’s focus is on building a comprehensive understanding of the sources, fates and effects of runoff across Southern California, then using these insights to help managers design maximally effective BMP interventions.
SCCWRP’s stormwater BMP research is centered around four main areas: (1) Understanding BMP mechanisms and processes, which involves quantifying how different BMP treatment mechanisms and processes remove various levels and types of pollutants from runoff; (2) developing design criteria for BMPs, which involves creation of decision support tools that help managers select optimal BMPs and combinations of BMPs for specific geographical and environmental settings; (3) optimizing long-term BMP performance, which involves developing strategies for monitoring and maintaining BMPs to maximize their long-term performance effectiveness; and (4) maximizing watershed-scale benefits, which involves developing frameworks and solutions for optimizing the synergistic effects of BMPs to improve and protect overall watershed health. SCCWRP prioritizes understanding not just performance effectiveness of BMPs themselves, but also the way BMPs influence the health of receiving water bodies – from hydrology and physical habitat to water chemistry to the biological communities they support.
This year, SCCWRP will focus on supporting management decisions for how to optimize the long-term performance effectiveness of BMPs. SCCWRP’s focus for 2023-2024 will be on:
- Developing quantitative techniques and metrics for assessing BMP performance: Given the difficulty that managers have in choosing the “right” BMPs to address site-, watershed- and sewershed-specific objectives (due in part to the fact that many criteria can be used to assess success), SCCWRP is developing robust, quantitative ways to evaluate BMP performance based on multiple criteria, including technical effectiveness, site opportunities and constraints, and long-term maintenance requirements. The index scoring tools are intended to enable managers to choose from a wide variety of individual technologies in their BMP “toolbox” as they evaluate different potential BMP options for a given site. Drawing on data generated by BMP monitoring programs, SCCWRP will develop data structures and dashboards to support index calculation and compliance reporting, and to evaluate effectiveness of design and maintenance activities in near-real time.
- Developing a comprehensive regionwide BMP monitoring network: SCCWRP is working with the Southern California Stormwater Monitoring Coalition (SMC) to develop a regional program for site-scale BMP performance monitoring to answer critical management questions regarding BMP performance, design, and maintenance across Southern California. This monitoring network, which could be among the largest in the country, is predicated on well-defined research objectives, consistent and coordinated data collection, and a unifying framework for sharing data. Researchers will be able to leverage the regional monitoring network to cost-effectively generate robust, statistically relevant data sets covering a range of BMP types that serve multiple land uses across a spectrum of operating conditions. These data will be used to improve BMP selection guidance, streamline annual reporting, develop cost-effective asset management programs, and support Reasonable Assurance Analysis and Alternative Compliance. In parallel, SCCWRP is working with the SMC to develop technically rigorous approaches for measuring the effectiveness of non-structural BMPs (e.g., street sweeping) at reducing pollutant concentrations and loading; nonstructural BMPs are a category of management actions for which even less performance effectiveness information is available than for structural BMPs.
- Informing adaptive watershed management strategies: SCCWRP is working with regulated and regulatory stormwater managers to develop watershed adaptive management guidance that can support multi-decadal stormwater management planning. The guidance will help address the design of capital improvement projects estimated to cost billions of dollars in the coming decades. Although stormwater managers are building adaptive strategies into planning scenarios on a regular basis, these focal-point decisions are often ill-defined, non-specific and unquantified. The guidance SCCWRP is developing will address what decisions need to be considered, what management options might be considered for different outcomes, and how to generate the appropriate data to inform these challenging adaptive decisions.