Infiltration Summary Table
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Stormwater BMP General Overview Illustration Drainage Area Pollutant Removal Mechanism Location in Treatment Train Pollutant Removal 1,2 Potential Application 1 Cost Maintenance Requirements 3 Pre‐treatment 4 Habitat Quality 5
Infiltration Basin A natural or constructed impoundment that captures, temporarily stores and infiltrates the design volume of water into the surrounding naturally permeable soil over several days. In the case of a constructed basin, the impoundment is created by excavation or embankment.
Infiltration basin icon.png
5 to 50 acres Sedimentation / Infiltration End TSS: High

TN: Medium/High TP: Medium/High Chloride: Low Metals: High Oils and Grease: High

Pathogens: High
Residential: Yes

Commercial: Yes Ultra Urban: Limited Industrial: Limited Retrofit: Yes

Highway/Road: Limited
Low $0.5‐$1.3 CF Simple‐Intensive Needed Oil/Water Separator, Vegetated Filter, Sediment Basin, Water Quality Inlets Low
Bioinfiltration Basin Often called rain gardens, bioinfiltration basins use engineered or mixed soils and plantings to capture and infiltrate runoff. Pollutants are removed using highly permeable soils that are able to draw the basin down in less than 48 hours. < 5 acres Sedimentation / Infiltration Beginning TSS: High

TN: Low/Medium TP: Medium/High Chloride: Low Metals: High

Oils and Grease: High
Residential: Yes

Commercial: Yes Ultra Urban: Limited Industrial: Limited Retrofit: Yes

Highway/Road: Limited
Low $0.5‐$1.3 CF Simple‐Intensive Needed Oil/Water Separator, Vegetated Filter, Sediment Basin, Water Quality Inlets Medium‐High
Infiltration Trench Synonym: Infiltration Gallery A shallow excavated trench that is backfilled with a coarse stone aggregate allowing for the temporary storage of runoff in the void space of the material. Discharge of this stored runoff occurs through infiltration into the surrounding naturally permeable soil. < 5 acres Infiltration nd TSS: High

TN: Medium/High TP: Medium/High Chloride: Low Metals: High Oils and Grease: High

Pathogens: High
Residential: Yes

Commercial: Yes Ultra Urban: Yes Industrial: Limited Retrofit: Yes

Highway/Road: Yes
Low $1‐$4 CF Medium Needed

Oil/Water Separator, Vegetated Filter, Sediment

Basin, Water Quality Inlets
None
Dry Well Synonym: Infiltration Tube, French Drain, Soak‐Away Pits, Soak Holes A smaller variation of an infiltration trench. It is a subsurface storage facility (a structural chamber or an excavated pit backfilled with a coarse stone aggregate) that receives and temporarily stores stormwater runoff. Discharge of this stored runoff occurs through infiltration into the surrounding naturally permeable soil. Due to their size, dry wells are typically designed to handle stormwater runoff from smaller drainage areas. < 1 acres Infiltration hroughout TSS: High

TN: Medium/High TP: Medium/High Chloride: Low Metals: High Oils and Grease: High

Pathogens: High
Residential: Yes

Commercial: Yes Ultra Urban: Yes Industrial: Limited Retrofit: Yes

Highway/Road: No
Low $1‐$4 CF Medium Needed

Oil/Water Separator, Vegetated Filter, Water

Quality Inlets
None
Underground Infiltration Several underground infiltration systems, including pre‐manufactured pipes, vaults, and modular structures, have been developed as alternatives to infiltration basins and trenches for space‐limited sites and stormwater retrofit applications. These systems are similar to infiltration basins and trenches in that they are designed to capture, temporarily store and infiltrate the design volume of stormwater over several days. Discharge of this stored runoff occurs through infiltration into the surrounding naturally permeable soil. X X X X X X X X X