Summary of volume reduction processes and BMPs associated with each process. Comments include qualifications and examples for the BMPs. Note that some BMPs occur in more than one process.
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Process BMP Comments
Infiltration Low impact development/better site design/sustainable development Includes such things as reduced street and sidewalk width, less curb and gutter drainage, scattered bioretention, shared pavement.
Trench or basin Must be properly engineered in adequate soils; proper maintenance essential
Perforated sub-surface pipes, tanks and storage systems Expensive but effective and space-saving.
Disconnected imperviousness Includes primarily rooftop drains and roadway/parking surfaces
Pervious (porous pavement) Includes a number of paving and block methods, or simple parking on reinforced grassed surfaces.
Bioretention (if contains infiltration element) Some bioretention facilities are designed to infiltrate.
Evapotranspiration Bioretention (rain gardens) Exposes runoff water to plant roots for uptake;can be under-drained and still effective.
Vegetated swales Provides water a chance to soak into the ground and be filtered as it flows.
Wetland/pond storage Combination of standing water surface and vegetative root exposure yields volume reductions.
Vegetated drainage corridor Connecting numerous features increases opportunities.
Recessed road/parking drainage Routing paved surface runoff to vegetated sump areas keeps it out of receiving waters.
Storage Rain barrel/cistern Small-scale runoff collectors keep water around for later re-use or slow release.
Rooftop (green roof) Storage on a roof prevents water from leaving the site; combining with vegetation (engineered green roof) makes it even better.
Conveyance Vegetated swale Provides water a chance to soak into the ground and be filtered as it flows.
Filter strips/buffers Variation of vegetated swale with side slope protection.
Landscaping Low Impact Development/Better Site Design Includes such things as scattered bioretention, shared pavement, native or prairie plantings.
Bioretention (rain gardens) Exposes runoff water to plant roots for uptake, can be under-drained and still effective.