With the record-setting rains and flooding occurring throughout much of the United States this spring, Land and Water Design, Haymarket, Virginia, received several calls regarding drainage. Here are three ways it answered.
1. Functional approach. Most do-it-yourself homeowners believe the way to solve bad drainage problems is to install a French drain, which is a 4-inch or 6-inch diameter perforated plastic or PVC drainpipe. Oftentimes, they are unaware that the pipe should be wrapped with a geotextile fabric to eliminate any infiltration of soil or other debris. The pipe is then placed at the bottom of a slope or an existing drainage swale and is backfilled with crushed bluestone and directed away from the house or structure. A 1% to 2% slope is necessary to move the water. Gutter downspouts should be connected to the French drain.
2. Aesthetic approach. Our most successful solution has been recreating the look of a creek or riverbed, utilizing the French drain system with a different twist. We excavate to a minimum depth of 18 inches and line the riverbed with 2 inches of sand covered with a geotextile fabric. Then, we fill it with 10 inches of bluestone, add another layer of fabric and top it with 6 inches of mixed river stone, ranging in size from 1 to 8 inches in diameter. Accent boulders are placed to emulate the look of a dry creek or riverbed.
3. Extreme solutions. For extreme runoff, we typically design and install a Flo-Well system within the dry creek/riverbed channel. These are a series of underground connecting modular dry wells made by NDS Inc., Woodland Hills, California. It is recommended to wrap the Flo-Well with geotextile fabric to eliminate soil migration.
Managing water, whether it is a drainage nuisance, aesthetic desire or ecological preservation concern, can all be managed by a professional landscape architect and should be a cornerstone of a design professional’s discussion with clients.