Most property owners, until there is a flooding problem, don’t even think about proper yard drainage. Water by nature will always flow to a lower elevation by the path of least resistance. Because of this fact, problems will occur when the original flow directions are blocked by new construction or were insufficient to begin with. Incorrect sloping and drainage on your property can cause the water to end up where you don’t want it, like under foundations, pavement and in the basement. A flooded basement or a cracked foundation is a problem that could cost thousands to repair, but could be prevented by taking a few precautions beforehand.
There are two methods of supplying water to a lawn, subsurface and surface. The subsurface method of water supply places the water under the topsoil and does not allow the water to go deeper due to the soil tension beneath. Also called the “water table”, this layer of water is in all soil at different depths according to the area. Too much water on the surface can raise the water table when it penetrates the soil and cause problem areas and flooding. Source of surface water are irrigation and rainfall. Sprinklers can cause problems in areas that have many impervious surfaces, such as urbanized areas.
Parking lots, driveways and streets, with all the concrete and pavement, leave the rainwater with nowhere to go. As far as lawns go, runoff will collect in depressions or saturate the edges. With no drainage assistance for the removal of excess water, when the soil gets to 100% saturation, it will start to collect in pools and will take longer to evaporate. All this extra water will slow plant growth because is decreases aeration in the soil around the roots and lowers the supplies of nutrients going to the plants. Excess water can also cause damage due to freezing in the winter. Proper drainage will prevent water collecting around your foundations, minimize the erosion of soil and protect your plants and other vegetation from disease and death.
Both subsurface and surface drainage solutions are vital for protecting your lawns and buildings. Surface drainage is the natural path that water takes when irrigating or during a rain, and can be controlled by rain gutters, downspouts, French style exposed drains or surface grates as well as grading and shaping your lawn to maximize the surface water removal with a minimum of soil erosion. Subsurface drainage is the process of placing pipes and drains in the lawn to remove the extra water that has been absorbed into the soil. Water travels in the soil by what is known as “capillary action”, which is a similar action as getting one side of a paper towel wet and seeing that it travels across the whole surface of the towel getting the entire thing wet. French drains are a great solution for excess water removal from the subsurface. Subsurface drainage will maintain healthy plant life, soil will warm sooner in the spring and suffer less freeze damage in the winter, and minimize damage to your buildings and foundations caused by frost heaving.