An infiltration basin captures stormwater and infiltrates it into the ground through highly permeable soil media designed to remove pollutants and promote groundwater recharge. The soils in these systems treat pollutants via settling, filtration, and biochemical activity.
Like bioretention systems and sand filters, infiltration basins are more effective at providing water quality treatment and groundwater recharge for small drainage areas. For large drainage areas, a waiver is required to use an infiltration basin for water quality and/or groundwater recharge.
- The bottom surface of an infiltration basin shall be be engineered sand or other approved soil media. A minimum of six inches is required.
- No vegetation is permitted in the bottom sand surface of an infiltration basin.
- Due to the high rate of infiltration, basins are not permitted to be located in area of high pollutant or sediment loading.
- No material or equipment storage should be located within an infiltration basin during construction in order to avoid compaction.
- Upstream slopes must be stabilized before the infiltration basin is made operational.
Cost: Infiltration basins are more efficient at meeting stormwater requirements and can therefore have smaller footprints. Maintenance costs are comparable to traditional detention basins.
Maintenance: Regular maintenance activities include sediment/debris removal and inspections for structural damage, erosion, and clogging of outlet and inlet structures.