Thornton Composite Reservoir

Steel Fab designed and manufactured four 12’- 6” wide x 28’ tall hydraulically operated stainless steel roller gates with hydraulic operating systems for the Thornton Composite Reservoir Project completed in 2015. The reservoir is part of the Metropolitan Water Reclamation District of Greater Chicago’s Tunnel and Reservoir Project, (TARP), also known as the Deep Tunnel Project. Thornton will provide nearly 8 billion gallons of flood water storage capacity making it the largest combined sewer overflow in the world. The reservoir will capture and hold storm water and sewage until the storm has passed and then pump the water for treatment to the Calumet Water Reclamation plant.

Our scope of supply also included heating systems for the roller gates and a 12’-6” x 28’ maintenance bulkhead.

The roller gates were designed for 375’ of head with the capability of sealing in both directions within the bifurcation conduits that feed the reservoir. One gate in each conduit is used for primary control and is fitted with an integral 30” jet flow gate. The other gate in the conduit is identical to the primary gate except without the jet flow gate and is used as a backup gate should the primary gate fail to close.

The primary roller gates are used for stopping the flow of storm water from the TARP tunnel after the reservoir has been filled to its allocated capacity. Once the storm event has passed, the jet flow gates will be used to control the flow of water back into the TARP tunnel and on to treatment.