Designing Retaining Wall Drains

Creating a drainage system for retaining walls is important as it would make sure that the walls would always be stable and would always have the ability to support and hold the soil to prevent erosion. A drainage system for a retaining wall is especially important in areas where seasonal rains are experienced. Because rain saturates the ground, the ground behind the wall can become soggy and water-laden, which can in turn, cause the lawn to flood. The accumulated water under the ground is also held by the wall and if the amount of water continues to increase, it can make the wall lean and unstable. Here are some information on how to make an effective drainage for retaining walls.

1. Check the surface of your retaining wall for any weep holes. Weep holes are spaces in the wall which allow accumulated water to seep through instead of gathering behind the wall. If you cannot see any weep holes, try to drill one after one to feet throughout the length of the wall. The holes should approximately be six inches above the level of your soil.

2. You can then dig a trench which should be at least six inches deeper and two inches wider than your perforated drainage pipe. Make sure that you would be digging the trench either along the entire wall length or in the areas which often flood. The trench that you should dig should ultimately depend on the amount of drainage that you need and the degree of flooding that you are experiencing.

3. Lastly, line the trench or trenches using landscape filter fabric and then fill them with gravel. Cover it with a layer of some filter fabric and then cover with six inches or more of fill dirt. If needed, lay a perforated pipe over a one-inch-thick gravel base layer in the trench or trenches to enhance the drainage even more.