MWRD TARP Tour Engineers at Terra participated in a tour of the Metropolitan Water Reclamation District’s (MWRD) McCook Reservoir.
What is it?
The McCook Reservoir is part of the MWRD’s Tunnel and Reservoir Plan (TARP). TARP is a system of deep tunnels and reservoirs designed to reduce flooding, improve water quality in the Chicagoland area, and protect Lake Michigan from pollution from sewer overflows.
Construction of TARP started in 1975. Similar to other older cities, Chicago has a combined sewer system. That means that the stormwater and the sanitary sewer lines flow into the same pipe with intercepting sewers redirecting sanitary sewers to treatment plants.
Unfortunately during heavy rainfall, the intercepting sewers would reach capacity and would cause the sewer to overflow and dump combined stormwater and untreated sewer water into Lake Michigan.
the new system
The Deep Tunnel system allows for the combined sewer and stormwater to flow to vast reservoirs during periods of heavy rainfall instead of being dumped into Lake Michigan.
The water is then pumped to the treatment plant after the rainfall.
Our tour started with an overview of the TARP project at the visitor’s center which had models of the project and equipment used.
From there we went to the pumping station which is located 350 feet below the surface. Two 17550 horsepower pumps are what is required to pump the water back up to the treatment plan. Terra also got to view an original computer dating back to the 70's. Imagine working on that beast!
The tour concluded with a bus drive to the reservoirs.
The project includes two reservoirs with a capacity of 5 billion gallons each. The reservoirs are currently under construction.
Stage 1 is scheduled to be completed by the end of this year. Stage 2 is forecasted to be completed in 2029.
When completed, the reservoir will provide 10 billion gallons of storage.