During the past several decades, a segment of Interstate 35W (I-35W) at 42nd Street, located in Minneapolis, Minnesota, has experienced flooding during intense storm events.The Minnesota Department of Transportation (MnDOT) evaluated several stormwater storage facility (SSF) concepts to mitigate flooding for events up to a 10% annual exceedance probability. Through collaboration with MnDOT, designers and third-party stakeholders, a frequency analysis model was used to evaluate the performance of the SSF concepts. The resulting SSF concept met flood-risk mitigation goals and was constructable. The collaborative approach for achieving the flood-risk mitigation objectives was carried throughout design because of the construction manager general contractor (CMGC) procurement method. Constructability and associated costs were considered and discussed between the owner, design, and contractor to develop efficiencies during the design phase. The final design consisted of six underground storage cells approximately 80 feet deep and 42 feet in diameter. This presentation will cover the evaluation of hydraulic storage design determination and constructability and cost efficiencies that were implemented under CMGC project delivery.