Penn. Rain Garden Reduces Flooding
Greenfield, Pennsylvania is leading the way in sustainable stormwater management with a new permeable sidewalk and 600-foot bioswale and rain garden in the Four Mile Run neighborhood. The area is prone to flooding, and the new installation will help to keep floodwater out of local basements and process pollutants in runoff.
An area in Greenfield, Pennsylvania notorious for flooding is testing a sustainable bioswale to mitigate runoff and potential damage from stormwater.
The bioswale – a landscape element designed to treat pollutants from rainwater runoff, in this case including a rain garden and drainage components – is in a Greenfield neighborhood called Four Mile Run. The project was built to prevent further damage in a flood-prone area where basements, homes and a local baseball field have been damaged by a lack of stormwater management. Rushing water occasionally floats cars down the street.
Officials consider project a proving ground for alternative stormwater management systems, since local, state and federal mandates are requiring the Pittsburgh metropolitan area to crack down on sewage overflows. The Allegheny County Sanitary Authority, which covers 83 municipalities in its service area, including Pittsburgh, could have to pay $2 billion to control overflows by the government's deadline in 2026.
The bioswale is about 600 feet long, and the rain garden contains plantings of black-eyed susans, daylilies and other flowers, decorative grasses, sweetbay magnolias and serviceberry trees. Eighteen inches of special soil and a gravel base lay below a layer of mulch to process stormwater and prevent pollutants in runoff from contaminating the surrounding waterways. The project also included a new permeable sidewalk, and together, the components are designed to trap 325,000 gallons of water or more annually.