Milwaukee, Wisconsin, sits on the shores of Lake Michigan at the confluence of three rivers: the Menomonee, the Kinnickinnic, and the Milwaukee. Its location in the Great Lakes Region means Milwaukee has a humid climate and is subject to rapidly changing weather, dramatic shifts in temperature, and severe winter storms, often producing several inches of snow.
In Milwaukee, one inch of rainfall amounts to 7.1 billion gallons of water. To control this influx of stormwater, the local utility, Milwaukee Metropolitan Sewerage District (MMSD), receives flows from two sewer systems – a combined system constructed over 130 years ago and a separate system built following World War II. MMSD serves 1.1 million customers in the Milwaukee metro area across 411 square miles. Throughout the mid-1990s MMSD used a gray infrastructure approach investing billions in deep tunnels used to store 521 million gallons of stormwater. Ongoing community concerns about flooding and CSOs prompted MMSD to consider an alternative approach.
In 2002, MMSD began deploying localized strategies including bioswales, permeable pavement, stormwater trees, rain gardens, and more to help capture stormwater where it falls, reduce the strain on centralized infrastructure, minimize pollution caused by overflows, and improve water quality. In 2013, to scale its localized green stormwater infrastructure program, MMSD approved a region-wide strategic plan designed to achieve zero sewer overflows, zero basement backups, and improved water quality by the year 2035 by capturing the first 0.5 inch of rainfall from impervious surfaces with localized infrastructure. At full implementation, GSI in the Milwaukee area will capture 740 million gallons of stormwater – 219 million gallons more than is captured by gray infrastructure. MMSD capitalizes these GSI investments on par with more conventional infrastructure funding the program with a combination of rate revenue and MMSD-issued general obligation bonds.
MMSD anticipates that this significant investment in distributed GSI will result in multiple co-benefits saving the utility millions of dollars and improving quality of life for the community. Particularly relevant now as communities face economic challenges, GSI is expected to create 500 green maintenance jobs at full implementation and, on average, 160 construction jobs per year.
The localized infrastructure programs are also estimated to have already increased property values by $667 million throughout the MMSD service area. By capturing stormwater and adding green space and shading, localized projects provide also multiple environmental co-benefits to the MMSD service area, including groundwater recharge, reduced carbon emissions, energy conservation, improved air quality, and water quality improvement.
From Milwaukee, Wisconsin, to San Antonio, Texas, as part of WaterNow’s Tap into Resilience initiative, WaterNow has interviewed over a dozen city and utility leaders already tapping into localized water strategies for fast, affordable, and impactful solutions to their water challenges. More details on MMSD’s Tap into Resilience case study are available on WaterNow’s campaign website here.