Rain Gardens Defined
Rain gardens are engineered practices aimed at improving water quality while mimicking natural systems. They function by directing stormwater runoff into a depressed area of a highly porous engineered soil mix filled with plants native to our region. This concept, called bioretention, causes plants to take up water and surrounding soils to infiltrate water that would otherwise flow directly to our surface waters.
The chosen plants mostly grow along stream banks in Virginia and are adaptable to the extremes of high rainfall in spring and low rainfall in summer. Pollutants are removed in this process that would otherwise run off into Four Mile Run, Tripp's Run, the Potomac River, and Chesapeake Bay.
Creating a Rain Garden
The City of Falls Church, Fairfax County, and Arlington County offer classes throughout the year on how to construct rain gardens. More information can be found on the Rain Garden Design and Construction Guide.
Rain Gardens on the Streets
The following are rain gardens throughout the city:
Rain Gardens in the Parks
In 2010 the city's Public Works Department secured grant funding from the Virginia Department of Conservation and Recreation's Water Quality Improvement Fund to install rain gardens in three city parks:
Berman and Lincoln parks used to experience standing water following rainfall while the storm sewer at Crossman Park drained the street directly into Four Mile Run. These rain garden installations in Berman and Lincoln Parks reduce standing water problems and added colorful seasonal plants that support a variety of native songbirds, butterflies, and beneficial insects.
The rain garden in Crossman Park intercepts and removes stormwater runoff pollution from Van Buren Street before it has a chance to enter Four Mile Run directly. Due to the lack of permeability in the soils of these parks, each of the rain gardens had to have an underdrain that was connected to an already existing storm drain.