Gabriel was excited to tour the almost-ready-to-be-opened McCook Reservoir, near MWRD’s Mainstream Pumping Station. When this reservoir goes online around Thanksgiving, it will hold 3.5 billion gallons of stormwater to help prevent flooding, improve water quality in Chicago area waterways, and protect Lake Michigan from pollution. Phase II of the McCook reservoir isn’t scheduled to be completed for another 10-12 years, but it will eventually add another 6.5 billion gallons of capacity.
MWRD’s Tunnel and Reservoir Plan (TARP) has been process since the initial tunnel construction started in 1975. The four TARP tunnel systems are designed to flow to three huge reservoirs, and the system will have a total capacity of 20.55 billion gallons when complete. The stored water is then pumped from the reservoirs to water reclamation plants to be cleaned before being released to waterways.
Learn more about how TARP works on the MWRD website.

Stage 1 of McCook Reservoir: the white masts are 150 feet high and will hold aerators to reduce odors

This ramp will stay in place once the reservoir goes online so MWRD can do routine maintenance and cleaning of the reservoir floor. The walls are all surrounded by a ‘grout curtain’ to keep stormwater in and groundwater out.