Met Council approves $7.5m engineering amendment for complex Lift Station L32A

Met Council approves $7.5m engineering amendment for complex Lift Station L32ATo mitigate construction risks on one of the region's largest lift stations, the Metropolitan Council has extended Braun Caldwell's engineering contract through the construction phase to oversee a specialized diaphragm wall installation.

The $7.5 million amendment brings Braun Caldwell's total contract value to $14.06 million and adds six years for construction support.

Lift Station L32A will utilize a complex diaphragm wall construction method to address challenging geotechnical and groundwater conditions near the Mississippi River.

Utility staff emphasized that retaining the engineer of record minimizes the risk of claims and ensures the original design team holds liability during construction.

The Metropolitan Council's Environment Committee unanimously approved a $7.5 million contract amendment on March 24, 2026, extending Braun Caldwell's engineering services through the construction phase of the new Lift Station L32A. Located in Fridley, Minnesota, Lift Station L32A will be one of the largest in the network, conveying wastewater from the northwest quadrant of the metropolitan area to the Metro water resource recovery facility. The project is currently at approximately 90% design completion and is nearing the bid phase. Tim Wedin, an assistant manager with Interceptor Engineering, told the committee that the lift station requires a complex engineering solution due to its size and proximity to the Mississippi River. While preliminary planning suggested a caisson construction method might be suitable, geotechnical investigations determined that a diaphragm wall construction is necessary to sink the large tank into the ground. This method addresses specific groundwater and site conditions while minimizing construction risk. The complexity of the diaphragm wall design, which utilized a specialized sub-consultant, resulted in higher-than-anticipated costs and necessitates specialized oversight during construction. The $7.5 million amendment adds six years to Braun Caldwell's contract to provide construction support, including clarifying designs, reviewing shop drawings, and resolving unforeseen field conditions. Utility staff emphasized the importance of design continuity as a risk management strategy. Retaining the engineer of record ensures that the firm holds the liability and errors and omissions insurance for their design work. Wedin warned that bringing in a new consultant for the construction phase would increase the risk of misinterpretations, claims, and the loss of specialized design expertise. The amendment brings the total value of Contract 20P210 to $14,066,704.