SRF was retained by South Washington Watershed District (SWWD) to complete the final design and construction documents and provide construction administration for the Central Draw Overflow Phase V project. The $5.8 million project includes more than one mile of 72-inch storm sewer at varying depths of 5 to 40 feet, 1,400 feet of stabilized channel that ties to the pipe into the downstream channel system in Cottage Grove Ravine Regional Park. Implementation of CDO Phase V provided the final connection of a multi-phased overflow project that provides flood protection and resiliency for several developing communities within the SWWD.
SRF coordinated with SWWD, City of Cottage Grove, Washington County, and private property owners to finalize the pipe alignment that was acceptable to current agricultural operations and fits within future development scenarios. SRF provided analysis of pipe jacking and open cut construction methods, design of D-load pipe due to the depth of the storm sewer, development of temporary and permanent easements and property negotiations, final construction documents, project manual, contractor-style cost estimate, Minnesota Department of Natural Resources Public Water Work Permit, U.S. Army Corps of Engineers permitting, and bidding support. The project was completed in 2020 and SRF provided construction administration, inspection and staking services for the SWWD.