What do you do when your yard is the lowest spot on the block and floods regularly, so much so that once or twice a year there is at least a foot of standing water? If that sounds familiar, it is because it is a common problem.
In this project, we needed a solution that would keep the flood water away from the house and foundation while making sure that none of our improvements would negatively impact the adjacent properties.
Capping the self-contribution
Roof runoff from the building and the runoff from the adjacent properties that sloped towards this rear yard both contributed to the flooding. Two rain barrels with a combined capacity of 260 gallons helped make a dent in the amount of roof runoff. This stored runoff was available to water a vegetable patch. The rain barrels were also connected to a time release valve that slowly drained the barrels between storms to maximize the available storage capacity.
From flooding to flourishing
Infiltration tests in the backyard showed rather permeable soils, which opened the door to fight the flooding with infiltration. The infiltration capacity combined with the runoff volume informed the design, sizing, and grading of a rain garden. The goal was to accommodate most rain events within the rain garden limits. The use of a resilient hardscape that would not be damaged by occasional flooding was key. So was the planting of a native prairie species that would tolerate being submerged for limited time periods. Maximizing the surface area of the rain garden was critical to spread out the runoff volume and limit the ponding depth.