Receiving runoff from outside one’s own property is fairly common. So is the occasional damage caused by water flowing across a property. What was unusual with this project was the amount of runoff that streamed across the yard. It had a negative impact on the building and septic system on the property.
Two networks of interconnected rain gardens effectively manage most runoff arriving from outside the property as well as the runoff generated on the property, and keep unwanted runoff away from the septic system.
1st line of defense
The first network was placed along the upstream end of the property and sized to intercept most of the runoff arriving from outside. It eliminated the prior sheet flow issues towards the house, the risk to the septic field, and minimized localized flooding.
From soggy to spectacular
The second network was strategically placed to receive the roof runoff from the building and garage, and also the basement sump discharge water. One rain garden section was set aside and turned into a wetland that was fed by the sump discharge, and ever since has grown into a horticultural jewel.
The first network is also tied into the second network with an emergency overflow. If the outside runoff overwhelms the first rain garden network, it can discharge the excess water into the second network, which in turn would still convey all runoff safely around the house and septic field.