Learn about ways to capture precipitation on your property and increase absorbent surfaces.
About runoff reduction
Building infrastructure that captures or absorbs rainwater on a property or diverts rainwater off a property is a practical personal solution to reduce flooding. Cisterns and rain barrels capture rainwater from roofs preventing it from reaching a property. Rain gardens and permeable pavement act to absorb rainwater on your property so that runoff will not occur. French drains work as a ditch to divert rainwater away from important structures.
Rain garden installation
A rain garden is a garden in a depressed area of a landscape that is designed to temporarily hold and soak in rainwater. Rain gardens reduce runoff from roofs, streets, and/or driveways. The amount of gallons of rainwater that a rain garden can hold depends on the square footage of the catchment area and the depth of the rain garden. In general, rain gardens are typically built to hold 1 inch of rainwater. The cost of rain gardens varies depending on whether you do it yourself or hire a contractor; the cost ranges from $5 - $45 per square foot. Some communities offer incentives to support the installation of rain gardens. To find out if your community does, check your local government website.
Rain garden in front of someone’s home (photo courtesy of Candace Stoughton, August 2010)
Cisterns and rain barrels
Cisterns and rain barrels both act to capture and store stormwater runoff from roofs. The difference between the two is that cisterns are larger, they can store runoff from larger roof areas, and they can be buried whereas rain barrels remain above ground. Besides stormwater management, these structures save water that can be reused for irrigation and other non-potable uses. Rain barrels typically retain around 50 gallons of water and cisterns retain between hundreds to thousands of gallons of water. Rain barrels cost between $90 and $140 and cisterns cost up to $1000. Some areas offer rebate programs for rain barrels and cisterns so be sure to check your local government site to see if you qualify.
Rainwater being filtered off a roof through a pipe into a rain barrel (photo courtesy of EPA)
Permeable pavement is a type of pavement that is highly pervious and allows rainwater to pass through it, which reduces runoff. By reducing runoff, permeable pavement manages stormwater and decreases flood risk. Permeable pavement can be used for your property’s road, driveway, patio, or swimming pool deck. The cost of permeable pavement depends on the material you use but tends to range from $5 - $10 per square foot. Permeable pavement can be built to hold anywhere from 5 to 19 gallons of rainwater per minute.
Permeable pavement being laid down in a driveway (photo courtesy of Alisha Goldstein, EPA)
A French ditch is a ditch with a perforated pipe or gravel laid in the ditch that carries water off a property and allows for proper drainage. First, make sure the drainage issues that are occurring are not being caused by leakage from underground pipes. Next, learn about the permitting process in your neighborhood before you start a french ditch drainage project. You can reach out to your local planning or zoning office to see if a permit is necessary. Make sure the ditch drains from a higher elevation to a lower elevation and that the outlet of the ditch does not drain into your neighbor’s property but rather to an existing body of water or curbside drainage system. How much rainwater can be carried by a French ditch depends on the width and depth of your ditch. A French ditch is a flood reducing project you can even install yourself.
French ditch in a yard.