Volume reduction practices

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.
Link to this table

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.
	Wetland/pond storage	Combination of standing water surface and vegetative root exposure yields dramatic volume reductions.
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.