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MMSD Accelerating Green Program to Reduce Overflows and Protect Lake Michigan

01/27/20 02:00:pm

(Milwaukee, WI) – Efforts to increase green infrastructure in the region received a major boost today as Commissioners of the Milwaukee Metropolitan Sewerage District (MMSD) approved a new program that will help capture and manage millions of gallons of water every time it rains.

Green infrastructure comes in many forms and sizes to help manage water where it falls to reduce water pollution. One inch of rain on MMSD’s service area equals 7.1 billion gallons of water. Green roofs, rain gardens, porous pavement, and other techniques help capture and hold water, so it doesn’t flow downhill, creating problems downstream or in the sanitary sewer system.

  • Green Roof

    Green Roof

  • Porous Pavement

    Porous Pavement

  • Bioswale


  • Cistern


To date, MMSD and numerous partners have created 33 million gallons of storage in the region using green infrastructure.

The District’s new program will significantly ramp up the total gallons of storage and identify techniques to help reduce the cost of green infrastructure.

To get the job done, MMSD is entering a public/private partnership with Corvias, a consulting firm that specializes in infrastructure needs through design, financing, construction, maintenance, and community services.

Corvias has delivered more than 900 green infrastructure projects across 15 states, from Florida to Alaska. The company has worked on similar large-scale stormwater programs that are most applicable to MMSD’s new program, including a 30-year project in Prince George’s County, MD.

Starting this year, Corvias will work with the District to identify target areas for green infrastructure, based on the ability to support program goals, such as reducing overflow volumes, reducing localized flooding, and improving water quality. Corvias and MMSD will build a supportive and well-trained engineering, construction, and maintenance community around these types of stormwater practices.  Corvias will also begin the design and construction of 8.45 million gallons in stormwater projects over the next three years. The project area includes all of Milwaukee County (except South Milwaukee) and Muskego. 

This project is innovative; the first of its kind for MMSD. It reduces the risk for taxpayers, as Corvias will only be paid based on performance (gallons attained).  The District’s program is backed by a $20 million budget over three years. Corvias will provide upfront financing, design, and construction. The company will be paid $2.365 for every gallon of storage created with green infrastructure. That figure includes management oversight and staff time. 


Learn how your organization can become a Fresh Coast Guardian. ​​​​​​Save money while protecting our rivers and Lake Michigan by adopting practices that harvest rainfall for other uses, or mimic nature, by draining it into the ground to reduce water pollution.

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The Coakley Brothers operate in a heavily urbanized section of Milwaukee, so installing green infrastructure such as cisterns, bioswales, porous pavements and rain gardens help them manage water where it falls. This green infrastructure project can hold up to 212,000 gallons of water.

Northwestern Mutual green roofs collect up to 512,000 gallons of rain each year and add green space to downtown Milwaukee. The green roofs help protect Lake Michigan by keeping rain from entering the sewer system.

MillerCoors green roof and rain gardens can capture and clean more than 96,000 gallons of water every time it rains which helps protect Lake Michigan and our watersheds from flooding and improve water pollution.