Building a French drain
Constant wet, soggy areas in your garden can be a problem, even more if you have flooding problems periodically. The solution is to build a drain that will redirect all the water from the rain or from uphill into rivers, ponds, lakes, etc. French drains are maybe the most popular and best solution.rclma French drains are actually small slopping trenches filled with gravel and pipes. Building a french drain is a straightforward process. Here are a few tips on how to do it.
Some of the tools and materials that you will need are:
- Shovel or spade
- ¾” aggregate gravel
- Landscape fabric
- Wooden stakes
- Line level
- Tape measure
The first thing you need to do is plan the French drain. See where in your garden/yard there’s a flooding problem. This is your starting point. Then figure out the route of the trench. It’s especially important to find a place to end the trench and get rid of the water. Sewers, lakes, ponds, rivers are perfect, but be careful not to drain the water in your neighbors back yard.
After you have planned the route, make sure you won’t damage any pipe lines, phone lines, etc, in the ground. Call you local authorities to see if it’s safe to dig. If you are planning to use the sewers for water disposal, see if you need a special authorization.
Another important aspect is that the the drain needs to have a slight slope. A 1% grade it’s enough for the water to flow. You can measure the grade by using a string and two sticks. Use a level to determine the grade. You can measure it for smaller distances, not for the entire path of the trench.
The trench needs to be 6-12 inches wider and at least 10 deep, following the grade.
After digging the trench, use landscape fabric to patch the entire trench. Leave at least 2 inches of fabric over the edge of the trench. Add a 2 inch layer of gravel and the pipes. Then cover the perforated pipes with gravel again and overlap the edges of the landscape fabric over the second layer of gravel. The landscape fabric will filter the water, preventing the trench from clogging.
After finishing the trench, add some sod over it and you’re done.