In a city known for flooding in the spring, when melting snow swells the Red River, Moorhead’s engineer Bob Zimmerman has been studying what he calls “the other kind of flood” — the kind that results from intense rainstorms.
This kind of storm, he said, would soak Moorhead with several inches of rain, potentially overwhelming the capacity of a stormwater system, flooding streets and damaging homes, public buildings and sewage infrastructure.
The city has faced some big storms in the last several decades, but climate science suggests extreme rains will become more common. That’s why Moorhead recently completed research to model flooding in a changing climate, thanks to a $75,000 grant from the Minnesota Pollution Control Agency.
Soon, many more local and tribal governments could get money from the state to prepare for increasingly extreme weather. The small MPCA grant program focused on climate resilience is undergoing a massive expansion. Minnesota lawmakers this year approved $100 million for water infrastructure and other projects like cooling centers for heat waves.
The money, a priority for Gov. Tim Walz’s administration, was not a subject of much discussion at the Capitol given the scope of Minnesota’s $17.5 billion surplus and debate over the sweeping DFL policy agenda. But in many years at the Legislature it would be considered a major initiative.
What the MPCA program will fund — and why
The MPCA has funded modest climate resiliency planning in this vein for a few years, most recently with roughly $1.79 million in grants paid for with money approved by the Legislature in 2021.
Cash has flowed to 21 cities and soil and watershed conservation districts, mainly in Greater Minnesota — including Moorhead, Duluth, Rochester, Byron, Renville and Cloquet.
This year, Walz’s MPCA asked the DFL-controlled Legislature for about $174 million to put climate resiliency plans into motion. Lawmakers approved most of that, $100.5 million. That amount of money makes it one of the biggest environmental and climate initiatives at the Legislature this year.
Frank Kohlasch is an assistant commissioner at MPCA, overseeing air and climate policy. He told MinnPost that the money would be focused on wastewater and stormwater infrastructure. But some of it could be used to mitigate other climate-related impacts like building cooling centers to deal with heat.
The water systems, however, are such a focus for a few reasons. One is that it’s critical infrastructure that people rely on, Kohlasch said. It’s also expensive to build — or fix if damaged. Much of it is aging and in need of repair anyway, according to the agency. And that type of infrastructure is also relevant for the type of changes Minnesota’s climate is already experiencing. For example, a wastewater plant is often near a river, where it would discharge treated water, putting it at risk from flooding after rain.
“We know that Minnesota is predicted to get warmer and wetter with more heavy precipitation events, more flooding,” Kohlasch said.
In a report to lawmakers in 2022, the MPCA said there was an average of 150 times annually where wastewater overflowed into lakes and streams because of wet weather. The report said more than 50 wastewater treatment plants were at “major to severe risk” of significant flooding in the next three decades.
For one example of infrastructure at risk, Faribault’s wastewater treatment plant was swamped by a flood after a big storm in 2010, forcing the city to pump sewage into a river. In the case of stormwater systems, which are meant to divert water from heavy rains to prevent it from flooding, Kohlasch pointed to Duluth in 2012, when the city’s storm infrastructure failed amid massive rains.
State and federal lawmakers have approved money for this type of infrastructure recently. The Legislature passed a historically large $2.6 billion package of publicly-financed construction projects earlier this year that included more than $500 million for water infrastructure, though that also includes drinking water plants. The national infrastructure bill included hundreds of millions for similar upgrades in Minnesota.
Nevertheless, the state believed in 2022 that needs for wastewater infrastructure alone were more than $5.3 billion.
The climate resilience money is not meant to simply supplement what was approved in the state’s bonding bill. Rather, it’s meant as an “add on,” Kohlasch said. Some of the projects may not even qualify for other types of state or federal funding. That would include “green infrastructure,” Kohlasch said, like rain gardens or more permeable pavements as opposed to traditional pipe systems.
The money could also fund some technical help for local governments and tribes, as well as cash for the type of planning Moorhead did. And at least 40% of it must be for projects in what the state defines as environmental justice areas.
At the Legislature, the MCPA grants weren’t frequently debated during a busy year that featured plenty of disagreements between Republicans and Democrats. In the House, Rep. Rick Hansen, a DFLer from South St. Paul who chairs the Environment and Natural Resources Policy and Finance Committee, said only that it was a governor’s initiative rather than a focus for him. House GOP lawmakers declined to comment on the money for the program.
But it was supported by the Minnesota chapter of the Laborers’ International Union of North America and the Minnesota AFL-CIO, as well as some environmental groups like The Nature Conservancy.
Moorhead looks at major upgrades for stormwater
In Moorhead, the city used the MPCA money to model the impact storms of various intensities might have on two big sections of the city. That included parts of town with older or, as Zimmerman put it, more “vintage,” infrastructure that was installed decades ago under different design standards that have since changed.
The study found several areas show an increased risk of flooding under a projected climate change scenario, which could justify tougher stormwater infrastructure.
“We used those projections to identify where the storm sewer system would have insufficient capacity,” Zimmerman said. “In other words it would be completely full and have street flooding and have potential for damages that go with that.”
Parts of the Minnesota State University Moorhead campus are among sections of the city at high risk of impacts from flooding under current conditions, at least in the biggest rain events.
Storm systems are not designed for the largest possible rain event, Zimmerman said, which would be too costly. But they are meant to handle more reasonable events, and limit flooding in extreme storms. In 2000, the Fargo-Moorhead area saw a massive 7-inch rain storm. Another in 2013 was around 4 inches of rain. The city study mapped flooding from storms between 2 and 4 inches.
(In older parts of town stormwater isn’t treated before it’s piped into the Red River. But in newer parts of town, there are ponds that treat runoff, Zimmerman said.)
Zimmerman said things like rain gardens can be a “bit of a challenge” in Moorhead. That’s because the terrain is quite flat, and heavy clay soils mean a rain garden isn’t as effective at soaking up water.
So while the city may consider “green infrastructure,” there’s more focus on basic options, like detention ponds that hold overflow water or underground storage tanks. And a big component of any upgrade would be a new, larger storm sewer. That’s straightforward, Zimmerman said, but costly. It involves digging up and reconstructing streets.
An estimate in the city study said work to reduce the flooding risk in the two parts of town would cost roughly $119 million. That wouldn’t all need to come from the MPCA’s grant program. Zimmerman said any major work would likely be done over many years and in many different projects and the city would look for many different sources of funding.
Still, they expect to try for another grant from the MPCA. “This grant funding opportunity that was funded by the legislature for us would be extremely timely having just completed this plan,” Zimmerman said.