Elm Road GS Water Intake Tunnel

27’-4”diameter of primarily unlined tunnel beneath Lake Michigan

Peak daily capacity of2.2 billion gallonsof cooling water

Challenges

The Elm Road generating station (ERGS) needed a cleaner, more efficient system of cooling technology.

The ERGS Cooling Water Intake System was constructed by Kenny/Shea JV.
It consists of a lake-water intake tunnel excavated in rock and is 9,226-foot long; 27’-4” in diameter.
Approximately 2,000 feet of the tunnel is lined to a finished diameter of 25 feet.
The new water intake tunnel can supply a total of 2.2 billion gallons per day of cooling water to the existing Oak Creek and new Elm Road power plants.

This design-build contract combined drill-and-blast and tunnel-boring machine (TBM) operations using main beam gripper TBM and rock-support selection based on the geotechnical-baseline reporting of rock mass classifications.
The dike wall structure was approximately 250-feet long and contained nine gates to provide cooling water under emergency tunnel bypass conditions.
Difficult marine construction involved dredging, cofferdam construction, and underwater work while maintaining a cooling water supply to the existing Oak Creek Power Plant (OCPP).
A sunken caisson construction was used for on-shore mining and OCPP shafts.
After completing tunnel mining, the TBM machine was disassembled underneath Lake Michigan and carried in pieces back to beginning of the tunnel for removal.