Thornton, IL

Thornton Composite Reservoir


Metropolitan Water Reclamation District of Greater Chicago


Spectrum Engineering, Inc.

Electrical Contractor

Gibson Electric 


MWH Americans, Inc.

General Contractor

Walsh / II in One Joint Venture

View of Gibson team members working inside of the Thornton Composite Reservoir

Value Delivered

Gibson Electric provided just-in-time electrical installations over a multi-year project for the Metropolitan Water Reclamation District (MWRD) of Greater Chicago.

Gibson delivered temporary power solutions for quarry, tunnel, and metal-lined tunnel construction operations. Their responsibilities included the design and implementation of an underground emergency call system, which was essential for maintaining a safe work environment throughout the duration of the project.

Additionally, Gibson installed a design-built cathodic protection system as well as a design-built hydraulics controls system for the reservoir's tunnel system.

Client Objectives

To increase the storage capacity of the Chicagoland’s wastewater reservoir system, MWRD determined it would transform a temporary reservoir in Chicago’s south suburbs into a permanent reservoir. This phase involved connecting the Thornton Composite Reservoir to the MWRD’s larger network of storm and sewage tunnels.


The tunnel project involved a variety of unique challenges, requiring innovative electrical construction solutions. During the project, Gibson delivered the following:

  • Design-built temporary power for mining, welding, and blasting operations
  • Designed structure-concealed raceway systems and installation drawings
  • Designed raceway sizing and routing of complex control systems
  • Installed over 1,000 feet of 6-inch raceway
  • Provided turnkey coordination between equipment vendors, distributed controls vendors, and plant operators
  • Integrated new systems with existing plant control systems

Client Background

The Thornton Composite Reservoir is part of MWRD’s ambitious Tunnel and Reservoir Plan, also called the Deep Tunnel Project, which is considered one of the largest civil engineering projects ever undertaken.