A French drain enables you to manage the flow of water runoff in your yard. Installing one entails laying perforated pipes in a deep trench and covering them with gravel. The pipes then do the work of collecting underground moisture and dispersing it to a safe outlet. If one side of your sidewalk slants toward a drainage ditch or storm water sewer, designate this area as your outlet, but space it far enough away so the drain water doesn't affect the sidewalk.
Things You'll Need
Synthetic filter fabric
4-inch rigid perforated PVC pipe
"T," "Y" or elbow connectors
Insert wood pegs in the yard where water collects after it rains. Lay a long rope on the ground from the wooden pegs to the drain outlet, adjusting it so the course is as straight as possible.
Spread a plastic tarp on the ground nearby and use a shovel to dig a 10-inch-wide drain canal that follows the course laid out by the rope. Dump the soil on the tarp and dig down 18 inches. From the beginning, dig a smooth, slight slope in the bottom by removing another inch of soil for every 8 feet of horizontal distance. Pack the bottom of the canal with the end of a 4-by-4 until it feels hard.
Lay down synthetic filter fabric over the bottom of the canal.
Pour 3/4-inch gravel over the bottom 6 inches of the canal and spread it with a hoe.
Place 4-inch rigid perforated PVC pipe in the center of the canal. Use "T," "Y" or elbow connectors to join lengths of pipe, depending on the angle at which they connect.
Spread another 6-inch layer of gravel over the pipes and cover it with filter fabric.
Scoop some of the soil you removed back into the canal until it's ground level. Replant the growth you removed and water it.
Make sure you set the perforated pipe in the trench with the holes pointing downward. Otherwise, debris will filter in through the holes and clog the pipe.