Diverting Rainfall Drainage

I have a small retaining wall in the back yard which has started to get undercut by runoff from the property behind me, which is elevated above the wall. The soil here is VERY sandy/sandy-loam, so when it rains with even moderate intensity the soil lifts/erodes easily. My main priority is to provide a way for the water to escape/redirect instead of tunneling down under the wall. There is a light slope from right-to-left where I believe I could dig down 6-8" and make a swale or trench and line it with plastic sheeting. I'm just not sure how to keep the water from burrowing down under the plastic and defeating the whole purpose. This area being mostly a greenbelt buffer means there are lots of leaves/debris the drop over time, so I'd have to run the leaf blower over it from time to time to keep from inhibiting water flow. Any other ideas other than a swale/trench? I thought about drain basins and tunneling the 4" pipe under the wall where it's already undercut, but with the amount of debris in the area it would get clogged quickly. The other "gotcha" for this area is there is a city water line and some communications utilities are running through this as well, so I will have to hand dig and have limited depth to work with. I have a tractor with FEL, but aside from fill dirt I don't think it will be useful here. submitted by /u/Haulnazz15 [link] [comments]

Jun 5, 2025 - 04:06

I have a small retaining wall in the back yard which has started to get undercut by runoff from the property behind me, which is elevated above the wall. The soil here is VERY sandy/sandy-loam, so when it rains with even moderate intensity the soil lifts/erodes easily. My main priority is to provide a way for the water to escape/redirect instead of tunneling down under the wall. There is a light slope from right-to-left where I believe I could dig down 6-8" and make a swale or trench and line it with plastic sheeting. I'm just not sure how to keep the water from burrowing down under the plastic and defeating the whole purpose. This area being mostly a greenbelt buffer means there are lots of leaves/debris the drop over time, so I'd have to run the leaf blower over it from time to time to keep from inhibiting water flow.

Any other ideas other than a swale/trench? I thought about drain basins and tunneling the 4" pipe under the wall where it's already undercut, but with the amount of debris in the area it would get clogged quickly.

The other "gotcha" for this area is there is a city water line and some communications utilities are running through this as well, so I will have to hand dig and have limited depth to work with. I have a tractor with FEL, but aside from fill dirt I don't think it will be useful here.

submitted by /u/Haulnazz15
[link] [comments]