Two pump stations in Milwaukee's western and southwestern suburbs are getting upgrades as the region's sewerage district works to keep pace with increasingly punishing storms and aging infrastructure that was never designed for today's rainfall levels.
The Milwaukee Metropolitan Sewerage District, which manages stormwater and wastewater for 1.1 million people across 28 communities, is moving forward with improvements to its Greenfield Park and Underwood Creek pump stations. Both stations sit in suburbs that have grown significantly over the past half-century, adding pavement and rooftops that send far more runoff into the system during heavy rain than the original infrastructure was built to handle.
Underwood Creek in particular has become a flashpoint for flood frustration. The corridor running through Wauwatosa and West Allis has flooded repeatedly, prompting MMSD to buy out properties, widen channels, and invest in pump capacity over the years. Many of the district's pump stations date to the 1970s through 1990s and are approaching or past their design life.
Source: NationGraph.
The urgency behind the upgrades is hard to overstate. Southeastern Wisconsin has been hammered by extreme rain events in recent decades, including catastrophic flooding in July 2010 and multiple other significant storms since. Researchers tracking regional precipitation have found that intense rainfall events, those exceeding three inches, have become substantially more common compared to mid-20th century baselines. What used to be called a 100-year storm has started showing up with alarming regularity.
MMSD built its famous Deep Tunnel system in the 1990s and early 2000s, a 28.5-mile underground network capable of storing 521 million gallons of combined stormwater and sewage, as a major step toward ending sewer overflows into Lake Michigan and area waterways. But that system was always meant to work alongside surface infrastructure like pump stations, not replace it. As climate pressures mount, the whole network has to perform.
The district has been ramping up capital spending significantly under its 2035 Vision plan, which identified billions in needed upgrades across the system. Financing has come through user rates, bonding, and federal programs including the EPA's Clean Water State Revolving Fund and funding made available through the 2021 Infrastructure Investment and Jobs Act. Rate increases tied to that spending have been a source of friction, particularly among suburban communities.
This project is part of a broader pattern of investment across the district. Similar pump station work has been underway at other points in the MMSD network as the district tries to reduce the basement backups and sewer overflows that have long plagued the region. MMSD is now hiring a contractor to carry out the Greenfield Park and Underwood Creek work, with the scope and timeline to be finalized through that process.
