Low Impact Urban Stormwater Retrofit
The 200 acres and 400 homes comprising the Towar neighborhood in E. Lansing and Meridian Twp. (Ingham County) Michigan experienced flooded yards, roads, and basements for more than 80 years, even during modest rains. The area is very flat.
Several years ago, approximately 150 rain gardens featuring native plants were created, in total occupying five and a half acres. Most are situated along roads. Several miles of expanded county drains augment the project. The gardens themselves run from patio-sized to the better part of an acre.
Concrete pipes (up to 24”) along the roads divert stormwater to the rain gardens, preventing residential flooding. The gardens are built on layers of sand and aggregate and have 12” perforated underdrains that accommodate filtration and slow progress downstream. The system is thought to be sufficient to handle a 100-year rainstorm.
The cost of construction was not quite $10 million, about half of traditional drainage improvements. The county drain commissioner maintains the system.