Empire Outfall

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Ames performed a three-phased project to expand the Empire Wastewater Treatment Plant Outfall and Rosemount Interceptor in Rosemount, Minnesota.

The project required Ames to perform construction activities within an existing utility corridor, around a busy technical college campus, and within the boundaries of the University of Minnesota’s UMore Park, a unique living laboratory for instruction on topics in agriculture, horticulture, and natural resources.

The initial contract included demolition, earthwork, structural excavation, backfill, aggregate base, and yard pipe installation, with the goal of expanding the wastewater treatment plant from 12 million gallons per day to 24 million. Crews installed more than 63,000 linear feet of pipe.

For the pipeline portion of the project, crews performed excavation activities and installed a 15-mile large diameter outfall pipe for carrying treated wastewater from the plant to the Mississippi River. Excavation quantities exceeded 1 million cubic yards of material, with some depths reaching 40 feet. The work scope also included the installation of fittings, siphon inlet, and outlet structures, and the use of structural concrete.

In the final phase of the project, Ames installed a dual double-barrel force main, fittings, and gravity sanitary sewer needed for improvements to the interceptor.

Markets: Water Resources

Location: Rosemount, Minnesota

Client: Metropolitan Council

Completion: May 2007


  • Earthwork
  • Aggregate placement
  • Pipe installation
  • Structural concrete