Why southern California needs a BMP regional monitoring network

The SMC’s Regional BMP Monitoring Network, expected to be operational by 2023, will enable Southern California stormwater managers to rapidly collect high-quality, comparable data sets on the field performance of structural BMPs.

In recent years, structural BMPs have been implemented at an increasingly rapid pace across densely populated southern California to improve and protect the health of watersheds. Today, southern California managers spend tens of millions of dollars every year to implement stormwater BMPs.

To date, however, managers have largely lacked the monitoring tools and infrastructure necessary to meaningfully evaluate the long-term performance effectiveness of structural BMPs.

Most BMP implementation decisions to date in Southern California have been made based on limited performance effectiveness data and analyses – often from outside the region – even as researchers know that local conditions can dramatically affect how structural BMPs perform. Significantly, this potentially non-relevant information has adopted into guidance manuals that are being widely used across southern California.

In particular, southern California’s relatively short but intense rain events affect BMP performance,  creating challenging logistics and few opportunities for conducting wet-weather sampling. The extended dry periods between storms also means that the range of pollutant types and their concentrations vary substantially across storms and locations.