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The conventional wisdom about stormwater is this: You don’t want it to linger in your town or city. After all, too much of it can flood a street or a basement.
That’s why city planners, engineers and developers have long designed the neighborhoods where we live and work to move rainwater as fast as possible out of the area, using concrete, pipes and drains.
But this approach makes water pollution and erosion worse. Ironically, it even exacerbates the flooding in some neighborhoods.
Now, nearly three dozen cities in the Kansas City region could shift their focus to catching, filtering and using rain where it falls — as states like Minnesota and cities like Austin, Texas, do.
“We used to say, ‘We have to get rid of water because it’s just a problem,’” said Tom Jacobs, the environmental director at the Mid-America Regional Council, which guides metropolitan planning in the bistate Kansas City region. “Now we’re saying, ‘Wait a minute, water is an asset.’”
The Kansas City metropolitan area — with its population of more than 2 million people — is moving toward a future where far more rainwater could get absorbed, repurposed and released back into the atmosphere with the help of rain gardens, rain barrels, restored woodlands, permeable pavers and green roofs.
This approach would help keep pollutants out of streams and beautify the city with more greenery that can also attract birds and pollinators, environmental planners say.
“Clean water and healthy, vibrant biodiverse habitat is a thing that a lot of people actually prize,” Jacobs said. “People want that.”
Clean water and habitat are powerful motivators in Minnesota, which has encouraged developers to use vegetation for preventing stormwater-related pollution and habitat loss since the 1980s.
“ We are the Land of 10,000 Lakes,” said Paula Kalinosky, with the Minnesota Pollution Control Agency. “Those outdoor recreation dollars are important to our economy and jobs.”
The City of Austin had similar motivations when it began requiring developers to help filter pollutants out of stormwater, also in the 1980s.
“We have really beautiful, crystal clear cypress tree-lined creeks that are one of the reasons why people want to live in Austin,” said Liz Johnston, environmental officer for the city’s watershed protection department. “People will go out and just hang out in the creek all day.”
In the ‘80s, new developments were going up near these swimming and fishing hangouts. Rain running off of all the new pavement and buildings risked polluting the creeks. So the city adopted anti-pollution measures just for those areas. Later, it expanded the rules citywide.
Then versus now
Nationally and internationally, experts say cities must embrace water, rather than rejecting it, to mitigate flooding and pollution.
This approach is sometimes described with the term “sponge cities,” coined by Chinese landscape architect Kongjian Yu, whose work focused on making urban areas more resilient against extreme weather and climate change.
Stormwater expert Greg Hoffmann thinks of the history of how big cities have dealt with stormwater in three eras.
Historically, they just had one goal: Get rid of it.
“A smart choice at the time,” said Hoffmann, who lives in Michigan and is the director of stormwater services at Maryland-based nonprofit Center for Watershed Protection. “Stormwater is dangerous — or can be dangerous.”
It could drown people and destroy roads. It left standing pools that could breed disease. So cities used pavement, drains and pipes to move water as fast as possible.
The second era — beginning around the 1980s in many places — aimed to fix a glaring problem: Neighborhoods with higher elevations got a far better deal than the ones downhill. Efficient drainage upstream translated to worse street flooding, pollution, property damage and other problems downstream.
“Rules came in that said, ‘You need to slow down the water before it discharges to the stream and impacts someone downstream,’” Hoffmann said.
Cities started requiring detention ponds in new developments. Rain hitting rooftops, driveways and parking lots could be funneled to these ponds through big pipes. Then narrower pipes in the ponds released water into the city’s stormwater system at a slower pace.
Yet these detention ponds only sought to address flooding and erosion. They did nothing about pollution.
“They just hold onto dirty water for a while and let it out slowly,” he said, which “leaves someone else to have to deal with that problem.”
Stormwater carries fertilizer from lawns and leaked car oil from streets. It ends up in streams and rivers, polluting not just habitats but the rivers and lakes where cities get their drinking water.
“The soap from washing your car that drains off into your driveway,” Hoffmann said. “It doesn’t feel like it’s anywhere near the river, but it gets there.”
Enter the third era: Designing cities to absorb stormwater and trap pollutants.
This approach processes water where it falls, rather than just detaining it temporarily. Thirsty plants, such as lush rain gardens and street trees, drink up the rain and exhale it back into the atmosphere. Healthy soil absorbs it. Both plants and soil help filter the water.
Minnesota tackles stormwater
Because of the 1972 Clean Water Act, many managers of stormwater, such as city stormwater systems, have to take steps to curb the pollution that pours out of their pipes and into waterways.
But states can shape the federally-mandated permits, so the requirements vary across the country.
Some states have set specific standards for properties to deal with rainwater on site, cutting down how much of it ever reaches the stormwater systems.
This is especially common on the East and West coasts, according to the Center for Watershed Protection. Less so in the middle of the country.
But Minnesota is one example of a Midwest state that carefully crafted its standard. The goal: Development shouldn’t increase the amount or speed of water flowing into local waterways after a typical rainfall.
To create that standard, a workgroup analyzed Minnesota’s rainfall patterns — and how much water a healthy, natural area absorbs before excess precipitation starts running into the nearest waterways.
Since 2013, new developments in Minnesota cities should be designed to handle 1.1 inches of the rainfall that hits their pavement, roofs and other hard surfaces. And certain construction projects outside of cities should retain 1 inch of rainfall. This aims to mimic how much rain those areas, prior to development, absorbed.
It’s meant to avoid exacerbating downstream flooding and erosion. Fast-moving water moves more earth, which can eat away at riverbanks, cutting into people’s properties. It can also harm habitats that Minnesotans value.
“We had a lot of trout streams in Minnesota and we’ve lost some of those because of a lot of sediment getting into the water,” said Kalinosky, who oversees the Minnesota Stormwater Manual at the Minnesota Pollution Control Agency.
Developers can use a variety of techniques to keep rainwater on site. However, Minnesota prioritizes absorbing the water into the ground — for example, with help from healthy soil and rain gardens.
The Kansas City region steps up to the plate
Now the Kansas City region could see a slew of cities taking similar steps.
Thirty-four local governments in and near the greater metropolitan area collaborated on several years of reenvisioning and rewriting stormwater standards.
The result is a manual tailored to the region and packed with details, such as how far to keep construction away from streams, so that waterways have more space to swell after storms without damaging property. (The exact setback depends on the specifics of the waterway.)
The manual sets a target for new developments and redevelopments to absorb 1.37 inches of rain on site without producing runoff.
This means developments would be able to handle 90% of the region’s rainy days.
Developers would also have incentives to leave land undisturbed where possible. Preserving corridors of vegetation along streambanks would help slow and absorb stormwater, for example. Saving topsoil is similarly beneficial.
“In traditional development, they go and scrape all the topsoil … and then start from scratch,” said Natalie Unruh, water quality planner at the Mid-America Regional Council. “We’re trying to say, if there’s stuff there that is decent species of trees or just natural areas in general, just leave it alone if you don’t need to be putting the building on it.”
Undisturbed, uncompacted soil and natural areas are the gold standard for absorbing rainwater.
Kansas City public works professionals gave the finished stormwater standards a key stamp of approval in December when they voted on it.
The American Public Works Association — with 800 members in the Kansas City metro — includes people who design, oversee or carry out a wide range of public projects and services, from park maintenance to sewer systems.
The association kickstarted the rewrite six years ago, when a taskforce of its members concluded it was time for the greater metropolitan area to improve its stormwater situation.
“There was a lot of concern that we weren’t looking at stormwater regionally,” said Tawn Nugent, past president of the association’s Kansas City Metro Chapter and an associate partner at engineering firm Trekk Design Group. “Stormwater doesn’t stop at city boundaries.”
The association then teamed up with the Mid-America Regional Council, which used money pulled together from cities, federal grants and the association to seek help from infrastructure and watershed experts, including the Center for Watershed Protection.
Nugent describes the finished product as a step forward for the metro, but one that comes with challenges. For example, each city will next need to go through its own process for potentially adopting the rewritten standards into their city codes.
For some, this could take a few years. Other cities might move faster.
“ At the end of this year, if we had a few that adopted it, I’d be pleased,” said Nugent, a civil engineer. “I’d call that a win.”
Cities could ultimately adopt varying versions. Building farther back from streams is easier in less developed areas, for example, than in a densely developed community. And some cities may decide to apply new stormwater rules only to new property developments and not, as suggested in the new standards, to redevelopments.
Because details such as these were points of debate during the drafting process, the new standards come with an appendix of potential rule modifications.
“There’s some communities that had some great hesitation about what it meant to their community,” Nugent said.
Updating stormwater rules also fueled debates in Austin.
In 2022, the city council updated its standards to favor green infrastructure like rain gardens and large, grassy depressions that filter stormwater through sand and sediment.
This was a change from special sand and sediment-filled concrete basins that also filter stormwater but that created a lot of unusable spaces for the city’s fast-growing population.
But some developers pushed back against the new green infrastructure requirements, and the city ultimately reached a compromise that includes some flexibility for difficult sites.
“That really helped make it so the development community … the ones who were a little more concerned, were okay with it,” said Johnston, with the Austin watershed protection department.
An ailing river system in Kansas City
The Blue River demonstrates how a regional approach to stormwater would have benefits across the Kansas City metro.
This 40-mile river and its creeks start in wealthy, suburban Johnson County, Kansas, and flow through more than 20 cities, taking in their stormwater and becoming increasingly polluted by the time it reaches Kansas City, Missouri, and empties into the Missouri River.
This means that more urban areas, including neighborhoods of color already bearing the weight of decades of redlining, underinvestment and discrimination — get the most polluted stretches of the river. Some of these areas are also served by old wastewater pipes that spill sewage into the Blue River system when too much rainwater pours in.
Darrian Davis is founder of the KC Urban Farm Co-op of Kansas City, Missouri. It’s the city’s largest Black-owned orchard, with more than 100 fruit trees.
The farm lies adjacent to the Blue River, which Davis sees as an opportunity for the community to connect with nature, but the river’s condition is a hindrance.
“ My concern is that it is polluted and that it is smelly and that it is trashy,” he said. “We should be able to do better.”
Davis and the Co-op are working to create kayaking access in the area.
“So we just want it to be pretty,” he said of the river. “We’re having groups of people on boats come out and just collecting trash all day.”
If city codes upstream reduce stormwater volumes and pollution levels, that would be a big help toward making this stretch of the river better for residents.
Without code changes, though, the problems could worsen. In Johnson County, ongoing conversion of natural areas and farms into suburbia is poised, in the coming decades, to send more stormwater down the Blue River.
Davis said it would help if commercial buildings captured rain on their premises with native vegetation.
“That’d make a big difference,” he said. “All the way up to rooftop gardens and terraces, water catchment systems.”
He also suggests rethinking the practice of manicured lawns, which exacerbate stormwater woes.
“Lawns, to be honest, may be enemy number one,” he said. “We’ve got to get to the point where we change how we look at lawns and grow native plants.”
Celia Llopis-Jepsen is an environment reporter for Harvest Public Media and host of the environmental podcast Up From Dust. You can follow her on Bluesky or email her at celia (at) kcur (dot) org.
Harvest Public Media is a collaboration of public media newsrooms in the Midwest and Great Plains. It reports on food systems, agriculture and rural issues.
