Professional Practice

Improving Water Efficiency: Residential Rain Gardens

The entry lobby overlooks a fern rain garden. ASLA 2012 Professional Residential Design Honor Award. Drs. Julian and Raye Richardson Apartments, San Francisco, California / Andrea Cochran Landscape Architecture

Rain gardens are a depressed vegetated area that use rainfall and stormwater runoff as irrigation. Rain gardens capture and hold water, usually through the use of native plants. By using highly-porous plant materials, rainfall and stormwater runoff can drain more effectively. Rain gardens allow approximately 30 percent of runoff to be filtered into the ground. A properly-designed rain garden can filter one inch of rainfall in four hours.

Instead of extending conventional water infrastructure at great cost, rain gardens can be used to collect rainwater, store it at the residential level, and reduce residential stormwater runoff. Like bioswales or bioretention ponds, the main role of rain gardens is to reduce water flow and limit water volume. Rain gardens also filter stormwater pollution, around 90 percent of copper, lead and zinc; 50 percent of nitrogen; and 65 percent of phosphorus, which could otherwise flow into storm drains and eventually bodies of water.

Homeowner can maximize the effectiveness of rain gardens by improving the quality of soil on their property. Green infrastructure and stormwater management systems are essentially useless if the soil has been degraded and compacted, reducing the flow of water and air, and restricting root establishment. The Sustainable Sites Initiative™ (SITES®) provides credit for using innovative soil remediation techniques, like subsoiling and adding soil amendments, to improve the ecosystem function of their soil.

Sources: Rain gardens fact sheet, Rutgers University; American Rivers

Organizations

Bluegrass Rain Garden Alliance

Rain Garden Initiative

National Gardens Club

Central Ohio Rain Garden Initiative

Toledo-Lucas County Rain Garden Initiative

Rain Garden Network

Research

"The Rain Garden Planner: Seven Steps to Conserving and Making Water in the Garden," Terry Wallace, Schiffer Publishing, 2008

“Rain Gardens: Sustainable Landscaping for a Beautiful Yard and a Healthy World,” Lynn M. Steiner & Robert  W. Domm, Voyageur Press, 2012

How-to Guides

Rain Garden Templates for Maryland, Low Impact Development Center

Rain Garden Manual for Homeowners, Erie County Conservation District

Rain Gardens: A how-to manual for homeowners, University of Wisconsin Extension

Rain Gardens Technical Guide: A landscape tool to improve water quality, Virginia Department of Forestry

Resources

Rain Gardens, Water Resources Program, Rutgers New Jersey Agricultural Experiment Station

Water Resource Program – Rain Gardens, Rutgers University

Soil Texture Fact Sheet, Cornell University Cooperative Extension

Rain Gardens: A Way to Improve Water Quality, UMass Amherst, The Center for Agriculture, Food and the Environment

Government Resources

Build a Rain Garden, City of Gresham, Oregon

Rain Gardens, County of Washtenaw, Michigan

Rain Garden Grants Program, Burnsville, Minnesota

RainWise Rebate Program, City of Seattle & King County, Washington

RainWise Access Grant, City of Seattle & King County, Washington

Yard Smart Rain Rewards, City of Kirkland, Washington

Rain Garden Rebate Program, City of Everett, Washington

Catching Rain Fort Wayne Incentive Program, City of Fort Wayne, Indiana

Projects

Private Residential Garden, Minneapolis, Minnesota
Oslund.and.assoc., Minneapolis, Minnesota

Drs. Julian and Raye Richardson Apartments, San Francisco
Andrea Cochran Landscape Architecture

Maple Hill Residence, Westwood Massachusetts
Stephen Stimson Associates Landscape Architects

Woodland Rain Gardens, Caddo Parish, Louisiana
Jeffrey Carbo Landscape Architects

Bud Clark Commons, Portland, Oregon
Mayer/Reed