View SCCWRP’s full thematic Research Plan for Stormwater BMPs (PDF)
2025-2026 Executive Summary
Stormwater BMPs (best management practices) are a wide-ranging collection of engineered technologies, landscape modifications, and non-structural 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 in semi-arid to arid regions. SCCWRP is developing BMP strategies and tools intended to bring clarity and confidence to the field of stormwater management.
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; 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 how the design, installation, and maintenance of BMPs influence water quality treatment.
This year, SCCWRP will work on three of these four main research foci – specifically, BMP mechanisms and processes, developing design criteria, and supporting management decisions for optimizing the long-term performance effectiveness of BMPs. SCCWRP’s focus for 2025-2026 will be on:
- Implementing a comprehensive regionwide BMP monitoring network: SCCWRP is continuing to work with the Southern California Stormwater Monitoring Coalition (SMC) to implement 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 is 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. SCCWRP is leveraging the regional monitoring network to cost-effectively generate robust, statistically relevant data sets covering a range of BMP types that serve multiple land uses under a spectrum of operating conditions. Among the initiatives that SCCWRP is leveraging the monitoring network to study are fecal indicator bacteria and microplastics; BMP effectiveness data are critically lacking for both types of contaminants across the industry. The monitoring network also is being used to study a range of conventional stormwater pollutants. The monitoring network data will be used to improve BMP design guidance, , develop evidence-based maintenance plans , and support Reasonable Assurance Analysis and Alternative Compliance. Data will also be used to develop a mechanistic model of biofiltration performance that enables researchers to explore the influence of design alternatives on pollutant removal, and quantify variability in long-term pollutant removal effectiveness.
- Quantifying effectiveness of non-structural BMPs: SCCWRP is working to measure the effectiveness of non-structural BMPs 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. Using a proof-of-concept method that SCCWRP previously developed to measure the influence of street sweeping on runoff water quality, SCCWRP will measure the impact of street sweeping on runoff water quality at multiple locations across southern California, including upper Los Angeles River and Rio Hondo River watersheds, representing the largest initiative of its kind across the USA. In a related effort in the County of San Diego, SCCWRP is conducting controlled field-scale experiments to measure the amount of rainfall and irrigation converted to runoff from turf replacement BMPs – which will quantify a key parameter for dry- and wet-weather flow management.
- Advancing monitoring technology: SCCWRP and its partners will continue to field-test and develop implementation strategies for open source, internet-of-things-enabled sensors that offer the potential to collect and access water quality and flow data in real time for a fraction of the cost of commercially available sensors. The new sensors, coupled with open source calculators that SCCWRP has been developing to simplify and standardize raw data processing, will support a long-term vision to reduce the cost and improve the quality of data collection and the ability to turn data into actionable information for stormwater managers.
