While water is essential for any landscape, too much of a good thing can actually be detrimental. In fact, without a drainage system, many lawns and landscapes are doomed to failure. Here’s a quick rundown on the various types of lawn drainage solutions, how they work, and where you should use them.
Surface Drain Systems
The simplest system to implement, a surface drain merely connects corrugated plastic tubes – usually buried underground – to the gutter-system downspouts and other water collection sources, which direct the water directly into the sewer system. Newer technology features “dry wells” that collect the initial rush of water and then allow it to disperse slowly into the surrounding landscape. Dry wells also allow plants to collect some of the water and sends this valuable resource back to the underlying groundwater table.
French Drain Systems
This type of outdoor drainage system is used to collect water from areas where too much of the liquid accumulates. Trenches are dug and a perforated pipe surrounded by gravel is installed. The pipe is also wrapped in a filter fabric that allows water to pass through but keeps out any rocks and dirt particles. Typically, the water is then directed into the sewer system although a dry well on a drier part of the property is sometimes used. This system is ideal for keeping low-lying areas from flooding.
Known technically as a “swale,” this water management system merely uses the contour of the land to direct water away from a home or building and into a bog planting – that is an area planted with water-tolerant plants – or a standard drain. Not difficult to actually install, a surface regrading should be planned carefully – preferably with the advice of a landscape architect or other landscape professional. In particular, the elevation drop needs to be at least one inch for every ten feet to be effective. This type of drainage system is most cost effective when large areas must be kept drained.
Typically located in basements or other subgrade spaces, a sump pump is a mechanical device that moves water that has been collected in a containment area – a “sump” – and pumps it away from the home into something such as a dry well or city storm drain. They are usually found in homes or buildings where flooding is a problem, or where the lowest portion of the structure is located below the water table. Sump pumps are ideal for these situations as the water will naturally collect at the lowest point – the sump basin – and the pump is automatically actuated when the water level in the basin reaches a certain height.
As their name indicates, retaining walls are used to keep back various materials – usually soil, but often water as well. These walls need to be carefully designed and installed by professionals, as there are many factors that could cause a DIY retaining wall to fail. In fact, the buildup of water behind poorly designed retaining walls is the number one reason for their failure. Typical uses for these drainage solutions include abruptly changing the elevation level of a landscape to provide more usable space for the homeowner.
Excess water is quite able to move large amounts of soil in a single rainstorm. For this reason, homeowners need to employ some sort of erosion control to alleviate this problem. Drainage solutions include the planting of shrubs, trees, or even a simple lawn. It is far easier than replacing the lost soil on a regular basis.