Over the past several decades, I-35W at 42nd Street, a major interstate artery in Minneapolis, has experienced flooding during intense storm events. Additional stormwater storage requirements prompted the Minnesota Department of Transportation (MnDOT) to hire Barr to develop flood-risk-reduction concepts. Complex hydraulic modeling, the need to understand ground conditions, and a restricted surface workspace posed challenges. The limited footprint and high groundwater conditions meant that the solution might require deep structures, such as tunnels and/or shaft-type construction. Barr provided geotechnical data of the underlying soil and bedrock conditions; accurate hydraulic modeling; and constructible concepts that not only met the hydraulic objective but also considered the challenging geologic conditions.
Barr led a multi-partnered team in final design of a 14-acre-foot stormwater storage facility to reduce highway flooding with the goals of maintaining a 100-year design life, minimizing life-cycle costs, reducing groundwater infiltration into the facility, and optimizing long-term maintenance. We completed hydraulic and structural design, including design of a weir structure to convey flow into the stormwater storage facility, connections between cells, and evaluation of impacts on water levels. We also developed a geotechnical monitoring program to provide baseline and construction monitoring for the duration of the project. Construction is expected to extend into 2022.
Senior Geotechnical Engineer
Vice President Senior Geotechnical Engineer
Senior Civil Engineer
Water Resources Engineer