Stopping to smell the flowers
Curb runoff with a rain garden
Arlene Marturano
Arlene Marturano a master

gardener, writer, and educator.

As an advocate of gardening

as a tool for learning, she

helped develop the Carolina

Children's Garden at the

Sandhill Research and

Education Center. She is an

education consultant with

T.E.A.C.H.

marturano@yahoo.com

We learn about the water cycle in elementary school, but not until adulthood and homeownership does the human element in the cycle become apparent.

Human activity, including housing, mall and road construction, and compaction of soil has altered the natural cycle creating as much as 30 percent of runoff.

By contrast, when rain falls in a forested area, most of the precipitation soaks into the rich humus, and there is very little runoff.

However, when rain falls on impervious surfaces like rooftops, sidewalks, roadways, and driveways runoff is greatly increased.

The formula for success or disaster in community development resides in the simple observation that impervious surfaces shed water; permeable surfaces absorb water.

Homes and property are an intricate part of the watershed puzzle. A watershed is a region of land draining into a river system. People not only affect the water cycle with impervious surface area but also by releasing substances, which dissolve, mix, transport, or suspend in water.

Rainwater runoff takes with it oils and grease from our cars; fertilizers, herbicides, pesticides and fungicides from our lawns and gardens; pet wastes; sediments from construction and erosion from lawns and gardens.

Neighborhood runoff reaches streams, creeks, rivers and lakes, and eventually an ocean. As a municipality decreases its permeable landscapes and replaces them with impermeable parking lots, roadways, and buildings, water quality suffers. The EPA estimates that the #1 source of surface water pollution is rainwater runoff.

Prince George County, Maryland has been a leader in creating community- based solutions for runoff at homes. They have designed bioretention cells or rain gardens for homeowner installation.

Bioretention is the practice of controlling water quality and quantity by using plants, soil, and microbes to filter runoff on site.

The prototype is adaptable to any setting. Start a rain garden after you have observed the flow of rain off your property. Locate the rain garden at the bottom of slopes, which is next to driveways or sidewalks, or on the side of the house to catch roof runoff.

Rain gardens need to be at least 10 feet from the foundation of a building to avoid drainage problems.

The garden will need to be excavated to form a basin six inch below ground level. A porous planting mixture of 50% construction sand, 30% topsoil and 20% compost promotes good drainage and breakdown of pollutants. The proper soil mix allows seepage rather than storage of water. A bog or wetland is not the intent of a rain garden. To direct downspout runoff to the rain garden, connect a length of plastic pipe to the downspout. The pipe may be buried or lay atop the grass.

Furnish the garden with plants that are low maintenance, drought resistant, and tolerant of wet feet for a few hours to a few days.

A variety of wildflowers, grasses, ferns, shrubs, and trees are willing candidates.

Add a layer of hardwood mulch when plants are secure because it suppresses weeds and absorbs heavy metals from precipitation before percolating into groundwater.

As with any garden, plants need the gardener's attention for the first year. Rain gardens are one grassroot solution to protect our natural resources.