Installation of a Drainage System

Perform a visual survey of the area where improved drainage is desired. Identify any low-lying areas or depressions and determine the proper direction for the excess water to travel. Keep in mind that the purpose of a drainage system is to direct water away from the affected area and that water always flows to a point lower than its origin.

Sketch the area of ground where the drainage system is to be situated and, based on your survey, the location and layout of the drainage runs.

Grade the area to smooth it and help to create a uniform slope if the area has not yet been landscaped. Grading can be performed with standard hand garden tools like shovels and rakes or with powered equipment, depending on the size of the job.

Refer to your sketch and begin digging trenches. Common trench dimensions are approximately 5 to 6 inches wide and 8 to 12 inches deep. Begin with trenches that originate beneath downspouts attached to the rain gutters on the roof and ensure the trenches travel in a downward slope away from the downspout.

Add gravel to the trenches. Use gravel that is approximately 1/2 inch to 1 inch in diameter and fill to within 3 to 4 inches of the top of each trench. Smooth the gravel to provide a level surface for the sand to rest on.

Top off the gravel with the coarse sand and smooth the surface. Do not use fine sand as it will not allow adequate drainage of the water.

Determine which method is necessary to restore the ground over the trenches to the original condition. For lawns, reseeding or installing sod are options. If using sod, be sure to rinse the roots on the underside of the sod to remove any fine sand or soil that may inhibit the absorption of the water. Use decorative bark, rock or gravel as the surrounding landscape dictates to best hide the drainage system.