Comprehensive Watercourse Management for the Menomonee River, WI: Milwaukee County Grounds Floodwater Facility

As a key part of an integrated floodwater management project, the Milwaukee County Grounds (MCG) Floodwater Facility has been designed in conjunction with downstream levee systems to sufficiently reduce water levels on the Menomonee River to provide a 100-year level of protection to previously flood-prone urban areas. The MCG facility functions by intercepting high flows from Underwood Creek, a major tributary of the Menomonee River, that would otherwise drive peak downstream water levels. Although the performance of the facility was designed and confirmed using a series of design events, each with different rainfall characteristics, the regulatory determination of flow reduction is based on continuous simulation hydrologic modeling using the Hydrologic Simulation Program — FORTRAN (HSPF). The urban setting of this project, the strategy required to reduce flood flows and the sophisticated modeling required to assess project performance all provided challenges to the MCG facility design. The project design has been completed and site regrading has been initiated. Project infrastructure will be constructed beginning in 2008 under a separate contract. Upon completion the MCG facility will reduce downstream flows sufficiently to remove 175 structures from the regulatory floodplain and likely save millions of dollars in flood damages.