MacKay Chicago Aviation Team Supports Award-Winning O’Hare Stormwater Project

Congratulations to the Chicago Department of Aviation on receiving the Illinois Section of the American Society of Civil Engineers' (ASCE) 2026 Outstanding Project of the Year Award for Projects Over $100 Million!

The award recognizes the South Conveyance Project at O'Hare International Airport, a critical component of the Chicago O'Hare International Airport Terminal Area Plan (TAP) redevelopment program. MacKay's Chicago Aviation Team served as a primary subconsultant to HNTB on the project, providing engineering expertise from early concept development through design and construction.

A critical piece of O'Hare's transformation

The TAP is part of a $9.5 billion redevelopment of O'Hare's passenger terminal facilities. The program will ultimately either construct or expand five major concourses, an automated people mover tunnel, and associated aprons, taxiways, and taxilanes.

The South Conveyance Project plays an important role in supporting that transformation by providing the stormwater infrastructure needed to accommodate the expanded terminal area.

At the heart of the project is an 8,800-foot-long, 14.5-foot-diameter tunnel constructed using a tunnel boring machine beneath active runways and taxiways. The tunnel serves as the primary conveyance for stormwater runoff from the TAP area to an expanded South Detention Basin.

The basin provides approximately 2,000 acre-feet of storage for runoff generated by a 100-year frequency storm, allowing water to be safely stored and gradually released to a nearby interceptor.

From concept to construction

MacKay's involvement in the South Conveyance Project began with concept-level studies from 2020 to 2021. The team then supported the development of tunnel alignments, profiles, and plans through 2024, including the design of six junction chambers, each approximately 24 feet in diameter and 50 feet deep.

MacKay also provided construction support services during the project's two-year construction period, helping carry the project from planning and design through implementation.

This long-term involvement reflects the depth of expertise our Chicago aviation team brings to complex aviation infrastructure projects, particularly those requiring careful coordination around active airport operations and major redevelopment programs.

Engineering that keeps a major program moving

The South Conveyance Project is an essential part of the broader TAP program and the ORD next series of terminal projects. The first of the new terminal structures is scheduled for completion in late 2028.

For MacKay, contributing to a project of this scale is about more than designing infrastructure. It is about helping create the systems that allow a major airport transformation to move forward safely, efficiently, and sustainably.

We are proud to have supported HNTB and the Chicago Department of Aviation on this award-winning project and congratulate the entire project team on this well-deserved recognition.