The Forest Park village council approved a long-term agreement Monday with village engineers to begin addressing the problems of local sewer overflow and seepage into basements.
Christopher B. Burke Engineering, Ltd. submitted a sewer separation evaluation study to the village which offers a three-phase program of assessment and infrastructure repairs over a series of years. The engineering company, which works as the village’s engineer, requested $158,000 to complete the study and work with the village to phase in the project.
The goal of the proposal is to replace 4-inch-diameter sewer pipes in phases with 8-inch-pipes in a tiered plan that would coincide with road repairs. The second goal is to disconnect the sewer system from the storm drain system, by installing a new storm sewer system that would discharge storm water (not sewage) into the DesPlaines River.
Burke’s proposal explains how it has assisted the villages of River Forest and Elmwood Park to develop storm water flooding plans. The Deep Tunnel Reservoir project is not scheduled to be completed until 2029, so the backups will continue for some time, they said.
Currently, in extreme storms, the combined systems in Forest Park overload and the combined sewer/storm water overflows into the Des Plaines.
There are more than 22 miles of combined sewers in Forest Park. The pipe diameters range from 12-inches to 66-inches. The village also has five and a half miles of “relief sewers.”
In Forest Park, storm water flows to the MWRD DesPlaines deep tunnel by entering 5-foot, 5-inch drop shafts at two locations: near the railroad in Concordia Cemetery near Van Buren Street and at a point just north of Roosevelt Road near the east side of the bridge.
These shafts and the Deep Tunnel they lead to are closed off when storm water fills the tunnel too quickly. This causes backup that leads to sewage/storm water surcharge into the basements of Forest Park homes.
The CBBEL plan would map out and design a separate storm sewer system that would drain by gravity into the Des Plaines River.
Using computer models, the plan would divide the village into three sections. North of the Eisenhower Expressway, (in the 100-600 blocks) the storm water sewer would run from north to south then travel westward along Van Buren to drain near Concordia Cemetery. Between the Eisenhower and Roosevelt Road, (800 -1100 blocks south) water would drain into the Roosevelt Road drop shaft. South of Roosevelt Road, (1400-2200 blocks south) water would drain into the Des Plaines River at Industrial Drive.
There already exists a GIS (Global Imaging System) atlas of sewer pipe locations, but CBBEL would also verify the depth and pitch of pipes. Using high water marks from the July 2010 and April 2013 storms, the engineers would have a baseline of potential flood depths and use computer modeling to create a system that can handle maximum water volumes.
The proposal also involves working with the village staff to phase in the plan, based on money available and timing.
Commissioner Mark Hosty said at the Aug. 4 council meeting that money for the project might be available through the village water fund.