The challenge
Detroit. Work continues on a sewer outfall tunnel for the discharge of wastewater into the Detroit River. On a night in April 2003, groundwater flows into the tunnel under a high hydrostatic pressure. Elevated concentrations of hydrogen sulfide gas in the groundwater fill the tunnel, necessitating an evacuation. The tunnel floods completely, stopping work. What is the solution?

The approach
Combine the expertise and skills of an ARCADIS team of engineers and scientists from the U.S., France, and the Netherlands. Within 40 days, the international team determines the conditions and practices leading to the incident and identifies actions for recovery and completion of the project. The recommendation: an innovative, proven tunneling technique used extensively in Europe, but novel in the U.S.

The result
A consensus among parties. An opportunity to participate in the design and completion of a new tunnel vital to Detroit. Proof of the value of ARCADIS' international network.