O’Hare Storm Sewer Project Wins Engineering Award

O’Hare South Conveyance Storm Sewer Project won a 2026 engineering award for a tunnel built beneath active O’Hare runways.

HNTB’s South Conveyance Storm Sewer Project at O’Hare International Airport has won the American Society of Civil Engineers Illinois Section’s 2026 Outstanding Civil Engineering Achievement Award in the more than $100 million category. Delivered for the Chicago Department of Aviation, the project used a 17-foot-diameter tunnel boring machine beneath two active runways and several taxiways. The stormwater tunnel was built without interrupting airport operations. It supports O’Hare modernization and future development.

Tunnel Beneath Active Runways

The tunnel was constructed through challenging subsurface conditions using an earth pressure balance tunnel boring machine. Real-time instrumentation and monitoring helped protect airfield infrastructure while excavation continued beneath the active airfield.

Mark Stephani, HNTB principal engineer of geotechnical and tunneling, said:

“Constructing a tunnel of this scale beneath an active airfield required careful planning, close coordination and precise control throughout excavation. The team developed an innovative solution that managed complex ground conditions, reduced risk at critical runway crossings and delivered the stormwater capacity needed to support O’Hare’s future.”

Stormwater Infrastructure Investment

HNTB served as engineer of record, working with the department and project partners to develop and implement the tunnel solution. The project used the construction manager at risk method, enabling early contractor involvement, evaluation of construction alternatives and work on the tunnel boring machine solution.

Zach Baughman, CDA Managing Deputy Commissioner and ORDNext program chief, said:

“The South Conveyance Storm Sewer Project is a critical investment in O’Hare’s future. Completed without interrupting airport operations, it strengthens our ability to provide the safe, reliable experience passengers and airlines depend on while advancing our long-term vision for O’Hare.”