Home   /   Projects   /   Stormwater Case Stud...   /   Flood Mitigation

Flood Mitigation Header Image

Flood Mitigation

Client: City of Waukesha    

Location: Waukesha, Wisconsin

E. Moreland Boulevard (USH 18) is a main arterial route between I-94 and downtown Waukesha. The area was prone to significant flooding, especially at the dead low point located just west of the intersection of E. Moreland Blvd. and Wolf Road. As the water level rose at the low point of the roadway, the overland relief route was into residential subdivisions, ultimately ending at the intersection with Highland Avenue. It is at this intersection where serious and destructive flooding occurred.

Donohue worked with the City of Waukesha to implement one of the recommended alternatives from the Stormwater Management Plan. Donohue provided XP-SWMM 2-D analysis of the Moreland drainage basin, developed alternatives to relieve the flooding, and determined the feasibility, cost, and flood reduction potential of various E. Moreland storm sewer alternatives. Donohue designed the selected alternative, a 60-inch relief storm sewer in E. Moreland from Wolf Road to a new Fox River outfall, and coordinated with WisDOT to complete the construction in conjunction with the E. Moreland Blvd roadway reconstruction project.

Open-cut construction methods were used to excavate and install the new storm sewer to depths of up to 32 feet. The sewer alignment was planned to minimize the disruption to existing utilities, including 12-inch water main, 16-inch high pressure gas mains, local storm sewer, and sanitary sewers. Several blocks of sanitary sewer and water main were relocated to make room for the 66-inch storm sewer.

Donohue worked with the City to meet the aggressive design timeline. The project construction date was accelerated by a year in order to coincide with the revised WisDOT construction schedule. Effective and frequent communication with the WDNR resulted in the City obtaining a Waterway permit for the new outfall and grading on the banks of the Fox River in record time.

Detailed traffic management plans were prepared to satisfy WisDOT requirements that the roadway be kept open at all times. Work at the busiest intersections was done at night to minimize traffic impact. Donohue also designed replacement water mains and water services for Waukesha Water Utility to take advantage of the pavement reconstruction.