Managing Residential Polluted Runoff - Prince George's County
Somerset, an 80-acre development in Prince George's County Maryland, sounds like your typical Washington, DC suburb but there's something unique here. Roads blend into the grass and homes sit on large lots with carefully placed landscaping. It is difficult, at first, to identify what is different, but it revolves around a feature known as rain gardens.
Goals
The developer, David Brinker, was interested in reducing his overall development costs, while also controlling polluted runoff from the community. Three prior attempts to develop the property using conventional runoff control methods ended in bankruptcy. Prince George's County was interested in how new low-impact development practices could apply in a whole development.
Process
Plans for Somerset had already been drawn for conventional ponds, curbs and gutters for controlling runoff, but Brinker wanted to replace the four required ponds with rain gardens. Rain gardens are shallow depressions, typically planted with colorful native plants, strategically located to collect and filter rain that falls on hard surfaces like roof tops, driveways and streets; they catch runoff before it flows to streams and rivers. Using rain gardens for controlling residential polluted runoff was a first; they had previously been used at commercial and industrial sites where conventional practices are expensive. Brinker was committed to this concept as a more environmentally sensitive and less expensive way to develop the site. After talking about rain gardens with Larry Coffman of the county's Department of Environmental Resources he redrew the plans.
Homeowners and potential buyers became excited and interested in helping when told they were helping preserve the Chesapeake Bay. They also perceived the rain gardens as free landscaping. Homeowners signed an agreement acknowledging their understanding of how rain gardens work. The Homeowners' Association maintains the common area and ensures that homeowners maintain their individual gardens.
Outcome
The rain gardens cost about $500 each - $150 for excavation and $350 for plants. About $100,000 was needed to install all the rain gardens, compared with over $400,000 that conventional runoff controls would have cost. In addition, by installing rain gardens instead of conventional ponds that require more space, six more homes were built, increasing the developer's profit.
More Information
Maryland Developer Grows Rain Gardens to Control Residential Runoff, US EPA Nonpoint Source News-Notes, Aug/Sept. 1995, Issue #42
Low Impact Development Technologies. by Anne Guillette
Low Impact Development Technologies.Prince George's County Department of Environmental Resources, Environmental Services Division - (301) 883-5834