The parts of a proper drainage system work together like a clock, without one part of the system, the rest of the system fails. When you have water and moisture at a higher location and need to divert it around a building or retaining wall, then you need a proper drainage system. This article entails the details it takes to create a proper flowing drainage system.
You’ll need a shovel, tape measure, level, rake and tamper as tools to start. For materials you’ll need landscape fabric, gravel, and perforated drain pipe at the length of your ditch.
You’ll also need a garden hose or string to lay out for your drainage system.
Start by taking the hose or string from the area you want to drain water from, to the area where you want to drain water to. Lay the hose or string out; avoiding the obstacles you don’t want to dig through like your prize begonias or porch. Put it aside a few inches from where you want to dig, because well, you don’t want to dig through your garden hose or string line.
After lay out is complete, begin digging. Start from the highest point and work to the lowest. At the highest point you don’t want to dig to deep, because as you reach the bottom, you’ll discover you’re going to have to dig really deep at the bottom. Generally as a rule, you’ll want to drop about an inch for every 4 feet of trench you dig. You should probably drive a stake at each end of your trench first and run a string line across it. This way you can use your tape measure to see how deep you are and that you are actually going downhill that inch per 4 feet.
After your trench is dug, unroll the landscape fabric into the trench. Add enough fabric to cross back over the trench later, add a few inches to that length. Line the entire ditch and overlap each seem by at least 4 inches or so.
Add a few inches of gravel into the trench. Take a 4 foot level and make sure it slops properly. You can take a 4 foot 2×4 and place a one inch block on one end to achieve the proper drainage slope. After this is done and the gravel is graded nicely, its time for the perforated pipe.
Lay the drain pipe in the center of the trench. At intervals, place some gravel on top of the pipe to hold it into place while you unroll the rest and lay it in the trench. Continue like this until you have the entire trench is filled with perforated pipe. Make sure you have plenty sticking out of the end, as you can always trim off the excess later with a utility knife. Bury the beginning of the pipe with the top slightly facing upwards and cover with landscape cloth to prevent gravel and roots from entering the pipe in the future.
Backfill the trench and perforated pipe until you have a minimum coverage of four inches. Tamp the gravel with your tamper, and add extra gravel where necessary. Now fold over the extra landscape fabric you left exposed from the trench. Place the dirt over it from the trench you dug earlier and tamp the soil with the tamper. Spray with a light mist of water and fill in any low spots.
The drainage ditch is now done. You can reseed the lawn, or replace with sod from a local landscape company. Trim the excess pipe at the end and cover with landscape cloth and dirt or gravel.