GINLC Newsletter: Detention Pond

The Grosse Ile Township School system (GITS) has undertaken a project to pave the area around the bus garage west of the football field. Both the employee and bus parking lots are to be paved, which results in a nearly two-acre plot of impervious surface. A detention pond has been designed to control run-off from this area. Members of the Conservancy were concerned about the location and design of the detention pond, because of the loss of a mini ecosystem currently in the natural area, and the loss of a potential outdoor learning site.

Three members of the Conservancy, Bruce Jones, Ken Tilp, and Pat Selby, met with the architect of the project, along with representatives from GITS, to understand the design requirements. While safety and liability issues as well as Wayne County requirements preclude the use of the site as an outdoor learning center, we left the meeting with a better perception of the pond.

The pond is designed to be a constructed wetland. Run-off from the paved areas will enter the pond, and leave either by evaporation or permeation into the pond sides and area below. The pond will only overflow into the storm sewer system during significant storm events, and then at a controlled rate.

A landscape plan has been developed to plant the pond, its edges, and an “upland” area with indigenous species, similar to what the Conservancy is doing at Intrepid Pond. In addition, the project design provides long-term maintenance direction to the school district. This direction encourages practices to promote wildlife, such as leaving perennial seedheads on plants over winter.

While the group was disappointed over the requirement to fence the area, we understand the school system’s constraints. We appreciated the district arranging for the meeting with the architect, so we could be better informed about the design intent, and the long term plans for the site.