RESIDENTIAL STORMWATER MANAGEMENT

What is residential stormwater management and why is it important?

The quantity and quality of stormwater runoff from residential areas collectively poses a great threat to our waters

Large impervious surfaces such as roofs, driveways and parking areas prevent rain from being distributed evenly across the ground. Instead the water is concentrated into channels and other drainages where it can easily increase in force and velocity if the drainage path is too steep and is also impervious.  As rainwater passes over impervious surfaces, it picks up sediment and other particles, nutrients, pathogens and chemical pollutants that cause pollution.  Anything that enters a storm sewer system or that flows from your residence directly to a nearby stream or lake is left untreated.  Although it seems like a small thing when considering one individual house or lot, polluted stormwater runoff from all of our residential areas collectively poses a great threat to our waters.  There are many things that we as individual landowners can do to protect the environment and improve water quality by managing stormwater runoff in our neighborhoods.  Even if you don’t live at the water’s edge, reducing stormwater volumes and helping infiltrate stormwater into the ground benefits the whole watershed.

How can one reduce stormwater runoff from residential property?

Here are some ways to reduce the quantity of stormwater runoff and in many cased improve stormwater quality as well.  A more detailed guide has been developed by the North Carolina Division of Water Quality entitled Improving Water Quality in your Own Backyard.  See the resources section below to obtain a copy.

• Capture water from a downspout in a rain barrel or cistern.  Rain barrels are a cost effective way to reduce stormwater runoff near its source and to catch the “first flush” of stormwater from your roof.  Rain barrels also provide a source of irrigation water for use in gardening or lawn maintenance.  A rain barrel is typically a 50 to 80-gallon plastic vessel that is attached to a roof downspout.  Homemade rain barrels can be easily constructed at a cost of approximately $60 per barrel or purchased as a unit at a cost of approximately $125 per barrel.

• Direct other downspouts away from pavement and toward grassy, mulched or planted areas.  You can attach a perforated plastic “French drain” pipe and bury it in order cross a stretch of lawn with the drainage.  If you don’t have gutters, dig a 3-6 inch deep infiltration trench under the drip line and fill it with gravel to decrease erosion as well as standing water.

• Create a residential rain garden.  A rain garden is a shallow depression in the ground that captures runoff from your driveway or roof and allows it to soak into the ground. NC State University has step-by-step instructions on creating a rain garden on the following web site: http://www.bae.ncsu.edu/topic/ raingarden/Building.htm. Rain gardens are typically designed to drain completely within 2 to 5 days.  Where existing drainage is located in close proximity to a rain garden, the drainage should be linked to the rain garden. Overflow from a rain barrel can be directed to rain gardens.

• Use a broom instead of a hose to remove plant debris and soil from your driveway.

• Reduce the size of impervious paved driveways, walkways, parking areas and patios.  As repairs are needed to parking areas and walking paths, consider using permeable paving such as interlocking pavers or gravel.