The long-term goal of the SMC’s street sweeping effectiveness study is to quantify if there is an effect of street sweeping in reducing the levels of contaminants entering storm drains via runoff.

Previous studies of street sweeping have established that conventional stormwater pollutants, such as bacteria and nutrients, are found in debris collected by street sweepers, but managers don’t know what portion of this pollution remains on roadways after street sweeping.

Under stormwater discharge permits, watershed plans commonly receive a credit for implementing routine street sweeping as part of a broader set of non-structural management actions to reduce runoff pollution. These actions, which also include public education campaigns, are known as non-structural stormwater BMPs (best management practices).

The SMC study will shed light on whether this runoff pollution credit – which is based on limited data and best professional judgment – has been appropriately set.

Managers will be able to use these insights to inform a range of routine water-quality improvement modeling and planning efforts.