rock lined creek

greater Milwaukee watersheds 

Greater Milwaukee Watersheds

Flooding and erosion of the watersheds in the greater Milwaukee area threaten public health and private property. Because watersheds boundaries do not necessarily follow municipal boundaries, reducing the risk of flooding requires looking at the watershed as a whole, including the complete river system and its tributaries.

A watershed is an area of land where all of the water, on the surface and underground, drains to a common place such as a lake, river, or ocean. MMSD's authority to reduce the risk of flooding is in Wis. Stats., sec. 200.31(1).

Milwaukee Metropolitan Sewerage District is responsible for reducing the risk of flooding for two reasons:

  1. Managing flooding promotes efficient use of the sewerage system by reducing infiltration and inflow.
  2. A regional government is the most appropriate entity to address watershed issues that involve multiple municipalities.

What Watersheds Are WIthin MMSD's Service Area?

legend of milwaukee area watersheds map

There are six watersheds within MMSD’s service area:

  • Kinnickinnic River
  • Menomonee River
  • Milwaukee River
  • Lake Michigan Tributary Drainage
  • Oak Creek
  • Root River

MMSD has discretionary authority to maintain these waterways. In the past, work has included: rehabilitation and removal of concrete, removal of sediment and flow-impeding objects, and widening floodplains for flood management purposes. In 1998, the District and local municipalities began the planning process for the development of an updated Watercourse System Management Plan. Flood abatement alternatives have been developed for each of the six watersheds. Phase I of the planning process incorporated the results of past planning efforts such as the 1990 Watercourse System Plan developed by the Southeastern Wisconsin Regional Planning Commission (SEWRPC) as well as new technical information on land use, peak stormwater flows, estimated damages, and other hydrologic and hydraulic information. Meetings with stakeholders in each watershed focused on data gathering, problem identification, and the development and prioritization of potential structural and nonstructural alternatives for flood management.


MMSD has invested hundreds of millions of dollars to reduce the risk of flooding in our area. At the same time, heavy downpours have caused hundreds of millions of dollars in property damage over the years and people have died due to flooding in our area.

  • Flooding in Thiensville

    Flooding in Thiensville

  • Flooding in Wauwatosa

    Flooding in Wauwatosa

  • Sinkhole in Milwaukee

    Sinkhole in Milwaukee

  • Water Knocks Down Basement Wall

    Water Knocks Down Basement Wall

From Flood Control to Flood Management

In the 1950’s, 1960’s, and 1970’s, MMSD implemented numerous flood control and streambank stabilization projects for watercourses within Milwaukee County. The projects completed up through the 1970’s predominantly focused on storm/flood water conveyance capacity. Flooding streams, creeks, and rivers at the time were viewed both as serious nuisances and/or as storm/flood water conveyance conduits that must be controlled. Rarely were the waterways seen as valuable environmental resources and community assets worth protecting. During this time, MMSD’s flood management program consisted primarily of straightening, deepening, and widening the various streams, creeks, and rivers within its jurisdictional area.

These channel modifications were deemed as necessary to rapidly convey additional storm and floodwater downstream. These watercourse alterations consisted most often of concrete-lined channels, configured as open channels with trapezoidal cross-sections, having both the low flow channel and side slopes constructed from concrete to reduce friction, prevent erosion, and reduce the need for frequent maintenance. These were the most commonly utilized flood control techniques for the day, and many streams, creeks, and rivers in the Milwaukee region received these types of alterations.

Clearly, the philosophy of flood control and accompanying engineering practices needed to evolve into something better, not only having public safety foremost in mind, but also having long lasting environmental and quality of life benefits connected with projects. This prompted MMSD in 1996 to invest in environmentally responsible systemwide watershed planning program. The program goals were to solve current flooding problems while putting policies and programs in place to prevent future problems. This new program’s philosophy was shifted from the old paradigm of flood “control” to flood “management”.

concrete lined kinnickinnic river in Jackson Park

Concrete Lined Kinnickinnic River in Jackson Park.

The shift in philosophy recognized A New Era in Flood Management.docx - 08/13/2017 3 that severe weather, extreme rainfalls, and resulting floods could only truly be managed to the extent possible and not controlled. The systemwide watershed planning program also provided an opportunity to reverse some adverse flood relief techniques utilized in the past. It was recognized that urban channels could be rehabilitated with proper planning to accommodate both flood flows and provide an environmental stream corridor that incorporates meandering channels with pools and riffle sections as habitat enhancements and have aesthetic, stable, and native species vegetated banks. All these features collectively provide an attractive community/neighborhood asset that can also stimulate economic benefits and increase surrounding property values.

MMSD Flood Management Projects

Kinnickinnick River progress MMSD

Kinnickinnic River Watershed

milwaukee river watershed

Milwaukee River Watershed

Additional Flood Risk Reduction Efforts

greenseams property

Greenseams®

Greenseams® is an innovative flood management program that permanently protects key lands containing water-absorbing soils to prevent flooding.

farmers in field working

Working Soils®

The Working Soils® Program aims to permanently protect privately held working land in the Milwaukee River watershed floodplain. Healthy soils store rainwater, recharge groundwater, and reduce water pollution.