Washed Away: Northwest Wisconsin Copes With The Costs Of A Changing Climate
Aug 19, 2019 07:37PM
● By Editor
A damaged culvert sits in the scoured bed of Troutmere Creek beneath a washed-out portion of Wildcat Road in Ashland County following the 2016 storm. Photo: Ashland County
By Will Cushman of WisContext - August 19, 2019
On the morning of July 12, 2016, Joan Elias awoke to discover she was stranded in her home. Elias, who lives on 21 mostly-wooded acres in rural Iron County, was cut off from the outside world by an unexpected - and unprecedented - deluge.
A powerful storm system rolled in the night before and stalled over northwestern Wisconsin. In many locations it delivered a torrent of rain measuring 10 or more inches - a typical summer's entire rainfall - in only 8 hours. Some locations in southern Ashland County received 14 inches of rain.
The landscape surrounding Elias's home, within the town of Gurney, is a patchwork of forests and hayfields growing on clay soils that predominate beneath a wide expanse of northern Wisconsin. Clay is slow draining, so much so that it's commonly used to line artificial ponds. The ground was already saturated by previous storms, meaning the clay had become a virtual regionwide plug for rain.
With nowhere else to drain, the rainfall choked streams and rivers with swirling runoff that resembled creamy tea, laden with the clay sediment and rich with red iron oxides. The water that rushed toward Lake Superior would reach volumes previously unheard ofin many local riverbeds.
Notable among these waterways was the Bad River, which drains about 1,000 square miles of northern Wisconsin into Lake Superior. Between 8 p.m. on July 11, when the storm system moved in, and 11 a.m. the following morning, the volume of water flowing through the Bad River in Odanah skyrocketed from 300 to 40,000 cubic feet per second - a 130-fold increase.
The Bad River's watershed includes Vaughn Creek and another small creek near Elias's property in Gurney. By daybreak, those creeks, which are typically a lazy trickle in July, had swelled into sizable flows, making the roads surrounding her home impassable.
But it wasn't simply a temporary flood that separated Elias and her neighbors from the surrounding world. Over the course of the day it became clear that the churning waters had devastated the local road network, and the damage was spread well beyond Gurney. Hundreds of washouts on roads across northwestern Wisconsin had cut off thousands of residents and visitors from workplaces, grocery stores, emergency services and medical care, all during the height of the summer tourist season.
Saxon Harbor, a popular campground and marina on the south shore of Lake Superior about 10 miles north of Gurney, was destroyed. At the nearby reservation of the Bad River Band of Lake Superior Chippewa, including the community of Odanah near the mouth of the Bad River, the flooding also caused extensive damageto homes, businesses and infrastructure. Across the region, major highway closures made travel even for residents who could leave their homes extremely difficult. In all, four people lost their lives across the region due to the storm and resulting floods.
Flood damage to property, roads, bridges and other infrastructure stretched from Wisconsin's border with Michigan's Upper Peninsula westward across Iron, Ashland, Bayfield, Sawyer, Washburn, Douglas and Burnett counties, an area encompassing nearly 10,000 square miles. Wisconsin Emergency Management documented the widespread devastation near Lake Superior and areas farther inland with extensive aerial surveys.
A majority of the road washouts resulted from failed culverts, the concrete or steel pipes that route streams beneath roadways. Most of the culverts had been installed decades prior to the 2016 storm under engineering guidelines that had not considered the possibility of a deluge of this magnitude.
The culverts were too narrow to handle the vast volumes of water racing through the watershed. Many became clogged with debris. Where they failed, churning floodwaters backed up and ate away at the roadway above. In many townships few routes were spared.
More than a dozen of these washouts were in Gurney.
"We couldn't go anywhere," Elias said. "My neighbors and I were stuck."
One of those neighbors had lung cancer and badly needed oxygen.
"He was stranded," said Elias. "So some of our other neighbors took it upon themselves to get him out by blazing a trail through the woods and fields. We all used that path until we could get out by the road, which was a week."
Within that week, crews hastily repaired enough roadways throughout the region so that isolated residents like Elias and her neighbors could at least get to and from their homes. But the work was only beginning.
State and federal authorities declared the floods a major disaster, freeing up funds for rebuilding, and local officials quickly began making damage assessments and applying for grants to rebuild and replace washed out infrastructure. Major detours would linger, however, as state highways and other major connectors remained closed for weeks or months.
Over the subsequent weeks, months and years, communities across northwestern Wisconsin would continue the rebuilding process, though their efforts have often come up against practical, budgetary and bureaucratic barriers, including federal and state rules that can incentivize short-sighted planning by encouraging and even stipulating that infrastructure be rebuilt as it was prior to the disasters. This requirement in particular has been a source of frustration for communities in northwestern Wisconsin - and elsewhere - attempting to construct more resilient infrastructure, including roads that can withstand an uncertain but assuredly wetter future in the Midwestern United States.
The 2016 flood followed a similarly intense storm in June 2012 that caused heavy flood damage in northeastern Minnesota, but also affected northwestern Wisconsin, including in the city of Superior in Douglas County, as well as western Bayfield County. After another major flood hit the region in 2018 - a flood that damaged roads at many of the same locations that washed out in the 2016 disaster - the local search for solutions has taken on more urgency.
Warnings Of Repeat Disasters
Chequamegon Bay is a large, shallow inlet on Lake Superior's southern shoreline. The bay is protected by the Apostle Islands archipelago and Chequamegon Point, and for centuries has been a center of settlement and commerce.
In the late 19th century, the cities of Ashland and Washburn sprang up along the bay's shores as local centers of northern Wisconsin's timber and mining industries. Today, the two cities are home to more than 10,000 people, and thousands more live and work in surrounding tourist, farming and Lake Superior Chippewa tribal communities. The region is also a gateway to the Apostle Islands National Lakeshore, which in 2015 drew nearly a quarter-million tourists who spent $36 million in communities surrounding the park, according to the National Park Service.
A June 2014 satellite image highlights northwest Wisconsin, northeast Minnesota and western Lake Superior, including Chequamegon Bay. Communities along Wisconsin's entire shoreline experienced major floods after extreme precipitation in 2012, 2016 and 2018. Photo: NASA Earth Observatory
The region largely developed before there was any scientific understanding of the interplay between weather, climate, ecosystems, land use and infrastructure. Settlers clearcut ancient forests and drained wetlands, both of which greatly reduce surface water runoff, to make way for farms and villages and a network of roads to connect them. In doing so, they at once built a local economy and set the stage for future problems.
In addition to its historic importance, Ashland is also home to Northland College, a small liberal arts school founded in 1892. Northland is part of an intercollegiate group of campuses that emphasize the environment called "EcoLeague," and the college prioritizes environmental sustainability, both in its academic programming and its operations. Northland faculty have helped lead the charge locally to address the region's vulnerability to climate change, and have at times offered blunt assessments of the problem.
"Chequamegon Bay is arguably the least climate-adapted spot in the country from an infrastructure viewpoint," said Randy Lehr, a former Northland professor of sustainable development, in a 2014 interview with Wisconsin Sea Grant. Lehr is now dean of science and math at Sierra College in Rocklin, California.
The Bad River spills over a portion of Hwy 2 near Odanah in the reservation of the Bad River Band of Lake Superior Chippewa in July 2016. A streamgage on the river rose from 300 to a record 40,000 cubic feet per second in 15 hours. Photo: Ashland County
Lehr went on to make a startling pronouncement: Precipitation estimates for the region, which engineers had for decades used to locate and size culverts, bridges and ditches, were woefully inadequate.
"As we've learned more about how weather patterns set up around here, we were way off - 40-50% off on precipitation estimates on the lower side," Lehr said at the time, adding that climate-change-driven extreme precipitation was likely to exacerbate the problem as the years unfold.
It wouldn't take long for Lehr's warnings to bear out.
Probability In Action
The July 2016 flood caused more than $38 million in damage to local infrastructure, much of it due to inadequately sized culverts, according to local officials. In various places, the precipitation and resulting floods were deemed indicative of a "100-year," "500-year" or even "1,000-year" event, terms that can lead to confusion.
For instance, a similarly extreme storm in June 2018 wreaked havoc in many of the same locations, even as construction crews remained in the midst of repairing damage from 2016. The 2018 storm and floods were in some places considered a "1,000-year" event and caused an estimated $13 million in damage to infrastructure, prompting yet another federal disaster declaration.
The 2016 and 2018 storms themselves followed a "100- to 500-year" storm in 2012 that caused major flood damage in Douglas and Bayfield counties and parts of Minnesota. Some communities, such as the town of Maple in eastern Douglas County, faced damage to the exact same stretches of road after each successive storm in 2012, 2016 and 2018.
Now, residents and local leaders are left pondering how the region has been pummeled with so-called 100-year or larger storms three times in six years.
"I have personally seen four 100-year storms" since the 1980s, said Tom Innes, who has been chairman of the town of Gurney since 1990. "And whatever this last storm was called - some people call it a 500-year storm, some people call it a 1,000-year storm - I don't know what it is, but I'm not four or five hundred years old."
Part of the issue is that the terms "100-year flood" or "500-year storm," are colloquial and imprecise shorthand for probability calculations. A "100-year" storm or flood is one that, based upon historical precipitation or stream gage data for a given location, has a one in 100 (or 1%) chance of occurring in that location over a 24-hour period in any given year. Similarly, a 500-year storm or flood has a 0.2% probability of occurring in any year, while a 1,000-year storm has a 0.1% chance. Simply because such storms have a low probability of occurring in any single year does not keep them from occurring in quicker succession than their names suggest.
Moreover, the storms in 2012, 2016 and 2018 were geographically massive events with widely differing precipitation totals across northwestern Wisconsin. What may have qualified as a "1,000-year" storm in one location could have nearby amounted to a much lower precipitation total and not even qualify for the "100-year" label.
Confusing terminology aside, Randy Lehr pointed out in 2014 that the probability calculations for these low-frequency, high-intensity storms were significantly underestimated in the region for decades. Because these estimates are one of the variables engineers use to calculate culvert sizes, the underestimation had disastrous consequences.
Keeping Pace With Precipitation
Scientists in the region are helping local officials better understand how they can try to minimize the impacts of the next disaster. One of those scientists is Matt Hudson, associate director of the Mary Griggs Burke Center for Freshwater Innovation at Northland College, a role Lehr previously held.
Hudson and his students monitor streamflow and water quality in Chequamegon Bay tributaries, as well as water quality in the bay itself. They're building a long-term dataset that Hudson hopes will inform future decisions related to local infrastructure and land use. Concern about the bay's water quality has grown since the 2016 and 2018 floods filled it with huge volumes of sediment and wastewater.
"The big thing people notice after a flood event is all of a sudden the bay turns brown, and nobody wants to be out there fishing or swimming, and people become concerned about water quality issues," Hudson said.
Hudson has increasingly served as an unofficial advisor to local officials who are trying to rebuild and improve the regional infrastructure system so it better withstands major storms in the future. Any large storm will send runoff into Lake Superior, but preventing washouts can help minimize environmental damage, as well as the cost of rebuilding.
Northland College professor Matt Hudson monitors stream flow and water quality in tributaries of Chequamegon Bay from his office. Photo: Will Cushman
Hudson explained that roads in the region have long been built under "100-year" storm guidance first developed in the 1960s and '70s and based on historical data from the mid-20th century. Updated estimates, available via the National Oceanic and Atmospheric Administration's Atlas 14 precipitation tool, factor in precipitation records through October 2011.
In northern Wisconsin, the newer estimates significantly increase the precipitation associated with storms that have a 1% chance of happening each year. For instance, in Ashland the previous estimate for such a storm was 5.4 inches of rain in a 24-hour period. The new estimate puts the total at 7.33 inches, more than one-third additional rainfall.
"And that doesn't include data from 2012, 2016, and 2018, when we had these large events," Hudson said. "So that current guidance from Atlas 14 is probably already outdated."
Factor in ongoing climate change effects, and the problems of planning infrastructure for future conditions becomes all the more difficult.
"What do we build for? What do we expect in the future? It's really uncertain," Hudson said. "It makes it really difficult to provide guidance."
Hudson hopes long-term streamflow monitoring can help, as well as climate models that point to more frequent large-scale storms.
Local officials who are responsible for rebuilding roads, meanwhile, hope they're able to make enough improvements to withstand more big storms when they come. But for many it has been a struggle.
The Difficulties Of Rebuilding
The seven counties in northwestern Wisconsin that have borne the brunt of the repeated storms and floods since 2012 are home to 124 townships and many more municipalities. Each of these townships, cities and villages is responsible for maintaining local roads within its borders. For the dozens that have recorded washouts and other damage due to flooding, a major challenge has been not only to repair the damage but to reinforce the roads so future floods aren't as destructive.
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