Site selection completed for study quantifying street sweeping’s efficiency

SCCWRP and the Southern California Stormwater Monitoring Coalition (SMC) have completed site selection for a two-year study that will measure the efficiency of routine street sweeping in removing contaminants that would otherwise enter storm drains and contribute to runoff pollution.

Field testing at the 10 selected sites, which will begin in February, will involve using a custom-built rainfall generator designed by SCCWRP to simulate rainfall on a set of swept roadway segments and a corresponding set of unswept segments, then looking for differences in pollutant levels in the generated runoff between the two sets of areas.

Half the sites will be swept with mechanical broom sweepers, and the other half by regenerative air sweepers, which will also enable researchers to compare the performance of two different street-sweeping technologies.

Street sweeping is a type of non-structural BMP (best management practice) that is a routine part of stormwater management programs in communities across Southern California. What has historically been unclear, however, is what portion of stormwater pollutants – sediment, nutrients, trace heavy metals, microplastics and bacteria – are removed from roadways through street sweeping.

The study follows the completion of a pilot study in early 2025 that developed a robust, repeatable method for quantifying the influence of street sweeping in reducing runoff pollution.