What a difference one degree makes: Iowa is getting hotter, bringing more frequent and intense storms

Donnelle Eller | The Des Moines Register

Show Caption Hide Caption Rerouting water in urban areas As rainfall amounts increase, experts look for ways to keep water from destroying homes.

Alan Lamb wonders how much more he can take.

Lamb's wife died last year after battling multiple sclerosis for nearly three decades.

In June, massive flooding filled his basement with water and sewage, destroying his Fourmile Creek home of 40 years.

Now thieves have taken some of the family's few undamaged possessions, including a widescreen TV and his late wife's collectible Cabbage Patch dolls.

"I’m just tired," said the 62-year-old retiree, who plans to take the city's $144,000 buyout of his home and head West. "I want to get this over with and get away from people."

Experts call Lamb and about 80 other homeless Des Moines residents "climate refugees" — people displaced by a catastrophic weather disaster.

Iowa is likely to see more: The state has gotten warmer over the past 30 years, and scientists expect the years ahead will get even hotter, a shift that's likely to hit cities with more frequent and intense rainstorms, similar to the torrential rains that ravaged parts of the Des Moines metro in late June.

All told, about 6,100 Polk County residents reported some flood damage.

"We are experiencing what the rest of the planet is experiencing. ... Wet areas are getting wetter, and dry areas are getting drier," said Jerry Schnoor, a University of Iowa professor in civil and environmental engineering.

Iowa is 1.3 degrees Fahrenheit warmer since 1988, according to an Associated Press analysis of weather data. Northwest Iowa has seen the greatest increase in temperature at 1.67 degrees, and the southeast has seen the smallest at 0.8 degrees, the data show.

Every other state warmed, too. The national annual average temperature climbed 1.6 degrees from 1988 to 2017. Alaska, Vermont and New Jersey posted the largest gains, and Washington, Oregon and North Dakota, the smallest.

Iowa ranked 38th among U.S. states.

Warming over the Gulf of Mexico is helping feed large rain events in Iowa and the Midwest, Schnoor said: "That's why we're prone to these great downpours like Des Moines saw on June 30."

Climate change, combined with rapid development and increased drainage from upstream farmland, have city, state and federal leaders scrambling to make adjustments.

They're installing bigger pipes to carry larger amounts of stormwater; reassessing how they build roads, bridges and levees; restoring oxbows and wetlands within cities; and increasing the release of water from reservoirs like Saylorville Lake, designed to prevent flooding.

Cities are even looking for flooding mitigation answers outside their metropolitan boundaries.

Clive, for example, is asking federal agencies to assess whether development over three decades would justify building upstream flood-control lakes, reservoirs or wetlands.

Officials estimate the Des Moines metro could see up to 12,000 more acres of development in the Walnut Creek watershed. It could add roughly $12 billion in value, with development stretching west to Dallas Center and north to Grimes.

"The sheer volume of new development would create, I would expect, a measurable downstream impact," said Doug Ollendike, Clive's community development director.

The city wants to know "how much worse the damage could get from increased flooding" in Walnut Creek.

Rising temperatures mean more intense rains

What does a 1.3-degree increase in temperature mean for Iowa?

"It’s not a large increase in temperature, in the sense of people noticing or feeling it," said Schnoor, co-director of the UI's Center for Global and Regional Environmental Research.

But it's significant because "it reflects a warming of the planet and warming of the oceans," he said.

Importantly for Iowa, the Gulf of Mexico is warming, generating more moisture that can be pulled into the states.

That has meant more frequent and intense rain events.

For example, six of the eight wettest years on record in Iowa have occurred since 1982.

Flooding has cost residents, businesses and farmers about $18 billion over nearly three decades, a University of Iowa study has shown.

The state ranks fourth nationally in the number of floods since 1988.

The flash flood that hit Des Moines, Schnoor said, "might have occurred once in 500 years, prior to climate change ... but now, it's much more common."

Iowa's temperatures — and rain events — will likely ramp up, said Schnoor and Gene Takle, an Iowa State University emeritus agronomy professor.

Five out of every 10 years, a five-day heat wave now averages 90 to 95 degrees in central Iowa, Takle said. By 2050, the average will climb 7 degrees.

And once every 10 years, it will spike 13 degrees, pushing the five-day heat wave as high as 108 degrees Fahrenheit, said Takle, who is contributing to the Fourth National Climate Assessment, a scientific analysis of climate change, mandated by the 1990 Global Change Research Act.

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The Midwest is projected to see the largest increases.

"The projections for the future are quite sobering," he said, adding that the impact will affect businesses, people and governments.

Farming, historically important in Iowa and making up about a quarter of the state economy, could be among the industries hardest hit.

Imagine corn trying to pollinate in a 108-degree oven, Takle said.

"It's a no-brainer. Pollination can’t occur at those temperatures," he said.

"And if you raise the temperature in those hog buildings by 13 degrees Fahrenheit in the dead of summer, no amount of additional air movement by fans is going to cool" them.

"They'll have to look at adding air-conditioning," Takle said.

A call for cities, farmers to work together

In a forgotten wetland in Urbandale, John Swanson points to a restored oxbow that will help hold and slow water that runs off a nearby residential development under construction.

"Roads and rooftops don't hold water," said Swanson, a watershed management coordinator for the Polk Soil and Water Conservation District.

The oxbow, snaking through the valley, worked to slow June's rains from rushing downstream.

"We want to hold the water back, before it gains momentum," Swanson said. Otherwise, "by the time the water gets to Clive, there's nothing they can do. There's simply too much."

That's why central Iowa leaders are trying to work together, reaching out to farmers upstream, to fight flooding, Swanson said.

Teaming up can help upstream growers add conservation practices that improve or protect soil, or help pay to take environmentally sensitive land out of production.

"It's what makes this complicated: Clive can't do it by itself. Urbandale can't do it by itself. And farmers can't do it by themselves. No one alone has enough money to do it all by themselves," Swanson said.

He and his co-workers are talking with developers, farmers and other landowners about places where more wetlands, ponds and other flood-control measures could be built to help "keep water where it falls."

The practices also can improve water quality by cutting nitrogen, phosphorus and bacteria levels that threaten drinking water supplies.

The storage needs are great: The Fourmile Creek watershed management plan calls for building about ​​​​​​​600 acre-feet of upstream storage, for example. An acre-foot is the volume of water necessary to cover 1 acre of surface area to a depth of 1 foot.

After two large retention projects fell apart, Swanson hopes the area's first 200 acre-feet project will come together in Ankeny.

"It's a long process, putting together willing landowners," Swanson said.

It's not just large floods that drive the need: With development, storms with less than 3 inches of rain now have a greater impact than those with close to 5 inches when the state was covered with prairie.

Streams deepen and widen with more water running through them, Swanson said.

"That's bad for the environment," he said.

"But it will impact residents, too, when houses start falling into the water. And when their cities have to spend millions stabilizing streams."

'We were lucky,' Des Moines official says

The June 30 flooding could have been worse, officials say, had the rain spigot not shut off, and had the U.S. Corps of Engineer not cranked up its release of water from Saylorville reservoir sooner.

"The corps has realized that the protection level of the reservoir is not as high as it used to be, so we need to empty it out faster," said Jonathan Gano, Des Moines' public works director.

The shift is driven by climate change, along with changes in land use — increased development and agricultural drainage, said Dayne Magneson, Saylorville's assistant operations project manager.

Starting about five days earlier, officials began releasing 4,000 cubic feet of water per second more than called for in the water-release plan the corps has used for 40 years.

Watch as water rushes through Saylorville Dam The water rushing through the Saylorville Dam into the Des Moines River is an impressive sight.

The corps is considering permanently changing the plan to deal with increasing rainfall.

"We used to see 33 inches of rain a year. Now it's close to 50 inches certain years," he said.

Deviating from the plan "kept us from going over the spillway," Magneson said.

"We were very lucky," Gano said.

'I don’t think we’re naive' about projected development

Development in the Des Moines area has a big impact on flooding, said Ollendike, Clive's community development director.

"The amount of rainfall in developed spaces has had a continual impact on us," he said, adding that Clive is about a tenth of the 83-square-mile Walnut Creek watershed. But it gets 92 percent of the runoff.

About 400 acres of farmland each year are turned into housing, warehouses and strip malls within the Walnut Creek watershed.

"I don’t think we’re naive (enough) to think we’re going to stop development," Ollendike said. "It’s important for communities. It’s important for Clive. But we need to find that balance, that partnership, where development" has minimal downstream effects.

By 2045, farmland will shrink from about half of the watershed area to a quarter, projections show.

That's why Clive officials have asked the corps and Federal Emergency Management Agency to analyze whether one or a series of lakes, ponds or wetlands could be built upstream to help cut the anticipated increase in urban flooding.

Clive officials also want to know what the threat is before considering whether it should buy out flood-prone homes or require home- and business-owners to raise their properties.

"It's traumatic enough. We don't want to go through it more than once," Ollendike said.

In addition to spending millions of dollars to raise Des Moines' levees, Gano points to the new culvert at 30th Street and Jefferson Avenue as an example of climate change's impact on the city.

Des Moines had to install a pipe 4-feet wider than initially planned "to accommodate the larger flows of rainwater that will come from more frequent and intense rainfalls," the public works director said.

It's part of $110 million the city is investing to replace its decades-old storm sewer pipes, which are to blame for a large amount of damage that hit Beaverdale and other northwest Des Moines neighborhoods.

Unable to make its way into too-small pipes, rainwater flowed between homes, inundating basements that were often unable to withstand the pressure, collapsing walls.

Des Moines leaders are expected to consider raising residents' storm sewer rates over five years to cut in half the time it will take to update the aging sewer system.

"It’s very hard to stand there and say, 'Help is on the way in 10 years,'" Gano said.

'We can't solve our problems with rain barrels'

It may seem over-simplistic, but rain barrels, bioswales and rain gardens could help reduce flooding's devastation within the city, said Josh Mandelbaum, a Des Moines council member.

"We can't solve our problems with rain barrels. But they can be a part of the solution, especially if you target hot-spots, where you know there are backups or where water flows through," Mandelbaum said.

Gano agrees, adding that June's flash flood left behind "pockets of devastation." About 2,000 homes sit outside areas slated for major improvements.

He proposes spending up to $3 million over five years upstream and in damaged neighborhoods to improve soil health, add rain barrels or create rain gardens to slow rainfall.

"It's another way of retaining water," Gano said.

And the 90-some homes the city plans to purchase for $13 million likely will be turned into green space that can soak up flooding from Fourmile Creek.

Lamb, the longtime Fourmile Creek resident, expects many of his neighbors will accept the city's buyout.

"They know another flood is coming. They just don’t know when. And they don't want to go through that ordeal again," said Lamb, who is living in his RV, parked in the driveway of the condemned house.

Lamb, whose home could be purchased this week, said he will rescue pictures, his bed, a grandfather clock and some other personal valuables from the house.

Otherwise, he's leaving behind the rest of his possessions.

"When they tear down my house, they can just haul it all away," he said.

Iowa carbon emissions

Iowa’s total carbon emissions ranked 25th nationally, based on 2015 data collected by the Associated Press that included all 50 states and the District of Columbia.

Carbon dioxide is the largest contributor of man-made greenhouse gases that trap heat in the atmosphere.

Nationally, electric generation and transportation are the largest contributors to carbon dioxide at 34 percent.

Experts say the carbon impact of electricity generation in Iowa might be less, given the state’s high percentage of wind generation.

Coal-powered electricity provided 45 percent of Iowa’s energy last year, with wind providing 37 percent.

Iowa’s per capita carbon emissions ranked 12th, the data show.