MINNEAPOLIS, MN — The I-35W underground stormwater storage facility (SSF), a first-of-its-kind underground solution to interstate flooding, received the Grand Conceptor, People’s Choice, and Qualifications-Based Selection (QBS) top-scoring project awards in the 2025 Engineering Excellence Awards competition hosted by the American Council of Engineering Companies of Minnesota.
Barr Engineering Co. shares this honor with the Minnesota Department of Transportation (MnDOT), which commissioned and facilitated the project. The Barr-led design team included TKDA and Brierley Associates, along with contractor joint venture Kraemer North America and Nicholson Construction (KNJV).
Over the past several decades, severe storm events led to significant flooding and explosive stormwater geysers that posed public safety risks and disrupted traffic and commerce near 42nd Street on I-35W — a major artery in Minneapolis, Minnesota, with an increasing volume of traffic that is expected to reach more than 250,000 vehicles per day within the next decade.
Barr led the design team to develop a first-in-Minnesota, vertical, underground stormwater storage system. The design and construction approaches were developed to address several critical challenges, including complex hydraulic conditions, deep excavation with a high groundwater table, and adjacent highway reconstruction — all in a restricted space wedged between the interstate and a residential area. The completed facility features six connected, 80-foot-deep chambers that together have the capacity to hold 4.5 million gallons of stormwater. The massive, underground SSF is designed to significantly reduce the depth, duration, and frequency of stormwater flooding along this section of the interstate.
“MnDOT, Barr, and all project partners successfully applied the construction manager/general contractor delivery method for this extraordinary project,” said Mike Haggerty, Vice President and Senior Geotechnical Engineer at Barr. “This approach engaged a construction manager during the design process, fostering teamwork and innovation at every stage. We’re thrilled with the outcome we achieved together."
