The SMC’s Regional BMP Monitoring Network has launched its second year of BMP performance monitoring, doubling the number of sites where field teams are collecting data to help stormwater managers quantify water quality treatment performance of structural stormwater BMPs and understand how maintenance influences performance.

Field teams are planning to collect data from up to 11 BMPs across southern California during the 2023-2024 rainy season.

Also in Year 2, the SMC is adding microplastics to the network’s suite of pollutants being monitored. The goal is to evaluate the effectiveness of structural BMPs at removing microplastic particles in runoff.

The SMC’s Regional BMP Monitoring Network is necessitated by the region’s relatively infrequent rain events, which limits opportunities to collect the amount of BMP performance data necessary to study the effectiveness of these engineered systems.

Development of the regional monitoring network began in 2020. The first year of field sampling was the 2022-2023 season, during which the SMC collected BMP performance data from seven BMPs across five locations, with as many as eight storm events sampled per site. The hydrology of more storms was also measured, which gives researchers greater insights into BMP operation, and supports estimating long-term performance without the intensive resources required for sampling. Four SMC member agencies – Riverside County Flood Control and Watershed Conservation District, Caltrans, County of San Diego, and County of Los Angeles –  took responsibility for setting up and managing the seven BMPs. Some BMP sites will collect BMP performance data on water quality treatment and maintenance, while others will collect data on either water quality or maintenance.

This year, additional BMP sites that are managed by Orange County Public Works, the City of Los Angeles Watershed Protection Division, and the City of San Diego are coming online, increasing the number of SMC member agencies with BMP monitoring sites in their backyards from four to seven. Other SMC member agencies are helping with data analysis.