Groundwater and how to control it

Groundwater is water that sits or flows below the surface of the ground. Capillary action can wick this water to the surface or the water may flow out the side of a slope when the hardpan or bedrock directs it to the surface. Even if the groundwater is not directly visible on the surface it can lead to muddy and swampy ground and make the area unusable.

The flow and dynamics of groundwater are controlled by many factors including organic matter and sand content in the soil, hardpan, surface slope, and surrounding geography. Often water is wicked toward the surface of a hill and then flows outward creating high water tables and wet springs around the perimeter of the hill where water flows out of the ground and creates puddles and swampy ground. Many low areas with little slope have water gathered in them creating swamps and pools of water.

Flowing groundwater is best controlled with curtain drains. These are french drains that are generally placed deep in the ground to collect flowing groundwater before it enters an area. They act as a curtain protecting areas below the drain. A curtain drain creates a lopsided cone of depression with a steep depression on the uphill side and a shallow depression on the downhill side. This can be used to manipulate your groundwater situation to achieve the water control you need.

Standing groundwater can be controlled with traditional french drains. In these low areas it is often necessary to use a sump pump system to remove the water to a disposal point. These sump pumps can be placed deep in the ground allowing the French drain system to be engineered with slope unrelated to the surface slope. French drains controlling stationary non-flowing groundwater create a fairly even cone of depression. On average a 24” deep french drain will have 15’ cone radius meaning a 30’ wide affected area. This is subject to soil conditions and the depth of the drain. Using these factors we can design and build a french drain grid to collect water in a large area.