Infiltration Best Management Practices (BMPs) treat urban stormwater runoff as it flows through a filtering medium and into underlying soil, where it may eventually percolate into groundwater. The filtering media is typically coarse-textured and may contain organic material, as in the case of bioinfiltration BMPs. These BMPs are sites ranging from small to relatively large. They are primarily designed for removal of stormwater runoff volume and pollutants in that runoff. They are effective at removing total suspended solids (TSS), particulate phosphorus, metals, bacteria, nitrogen, and most organics. Soluble pollutants such as chloride and nitrate typically through these BMPs and into underlying groundwater.
These BMPs, when designed with no underdrain, infiltrate the entire stormwater runoff volume for which they were designed.
Other BMPs can be designed to infiltrate stormwater runoff.