We didn’t discover until we built and moved into this house that the property had previously been used as a rainwater runoff area for the entire street. It became apparent very quickly, though, as we kept losing our driveway into the side yard with every rainstorm. Diverting the water away from our lot would have caused a lot of problems for the neighbors farther down the road but we figured out a way to collect it and divert it around our house safely and without having it wash out our driveway constantly.
The solution was to build a retaining wall, fill it only with gravel, and collect the rainwater in a french drain so it could be diverted into a ditch (hand dug – UGH) on the edge of the property. Retaining walls are safe up to the level we built it (2 feet) without reinforcement but anything taller would need some engineering so that the pressure of all the gravel doesn’t topple the wall.
Additionally, I fed the downspout into the same french drain so I wouldn’t have to worry about rainwater washing out the soil along the side of the retaining wall or ending up in the basement.
To our benefit, the project gave us a level place to park that we didn’t have before and a nice level planting bed.