Rain, Rain, Go Away! – Drainage
May 12th, 2015
May can be a rather wet month, so let’s talk about drainage. Typically in a yard, water comes from two places, surface drainage and drainage off the roof.
Slope is the main concern with drainage for both surface and roof run-off. Housing developers typically grade the yard away from the house toward the back or sides to a small swale in between yards. It does not take much slope to have correct drainage. A slope of one inch per 10 feet will be enough to get the water away from the house foundation and keep the water moving through the yard to the swale. If the water is not traveling in the right direction, add soil to the low area to raise the grade and allow the water to travel away. It also may be necessary to lower the grade in areas that are too high to let water pass the proper areas.
In the case of a surface drainage problem, if there is no slope to work with, other solutions are available. Water loving plants, such as redtwig dogwoods and willows, can be planted in the water logged areas to use the excess water. Large established trees are especially good at slowing water run-off. Often home owners notice surface water problems after cutting down a large tree(s). A French drain can also be useful to collect and direct surface water run-off. A French drain is a corrugated pipe surrounded in gravel and wrapped in landscape fabric. This pipe collects water throughout the yard, without allowing mud or sediment to clog the passage. A French drain can run to a swale, drainage inlet or to a dry well. A dry well is large, deep hole filled with gravel that collects water to dissipate into the subsurface soil on-site, recharging the groundwater table.
Roof run-off can be directed with underground corrugated pipe that will stub up into the yard several feet away from the house. With this, the water will be released in an area that will encourage correct drainage. Downspouts can also be connected to a dry well (described in the above paragraph). An eco-friendly consideration is to create a rain garden by directing the flow of the downspouts to a garden contoured to temporarily hold water to filter into the soil and recharge the groundwater table. Drought-tolerant and water loving plants in the rain garden decorate the landscape and enhance the wildlife habitat of your backyard.
Contact Shane’s Outdoor Living and Landscapes if you would like expert advice and installation as you explore the drainage options in your yard.