McCook Reservoir Main Tunnel

The McCook Reservoir Main Tunnel System Project was a part of the Tunnel and Reservoir Plan (TARP), also know as the Chicago Deep Tunnel. The intent of the TARP project was to reduce flooding in the Chicago metropolitan area. Holding reservoirs reduce the flushing of raw sewage into Lake Michigan by the temporary holding reservoirs.

CTLGroup was responsible for reviewing the concrete and mass concrete specifications, reviewing the most current available drawings, and reviewing the overall construction plan. CTLGroup worked with the Owner and Designer to review the concrete and thermal control specifications. We also provided concrete mix design development, materials testing at our laboratory, and assisted with the evaluation of QC testing results.


Civil Infrastructure

Energy & Resources

Consulting Services

Concrete Mixture Development & Qualification

Project Specification Review & Development

Mass Concrete & Thermal Control

Materials Science + Engineering

Laboratory Services

Concrete + Cement-Based Materials

At 3,000 feet long and 310 feet deep, the McCook Reservoir has been called the Grand Canyon of the Midwest.


Year of Completion


Hours Worked

3.5 B

Gallon Holding Capacity

Learn more about this project

Project Detail Form

Project Detail Form