Great Lakes Flooding: The Warning Signs That Homes Must Be Moved
Every fall, I take my environmental studies class camping at Sleeping Bear Dunes National Lakeshore on Lake Michigan. Some years the beach extends more than three meters to the water. This year, in many spots, there was no beach at all.
The story is the same throughout the Great Lakes. During my summer research trip to Lake Ontario and the St. Lawrence River, I lost track of the number of submerged docks and buildings; swimming near the shore of Lake Huron was a bad idea because of the high risk of electrocution from inundated boathouses that still had the juice flowing.
Water levels in the Great Lakes have always fluctuated. But climate change is throwing past patterns out of whack. Almost every Great Lake reached record levels in 2019. And the latest studies predict that levels might reach even higher in 2020.
But instead of engineered solutions, we should be concentrating on getting out of the way.
Lake Michigan's high water levels consumed beaches at Sleeping Bear Dunes National Lakeshore in 2019. Daniel Macfarlane / Author provided
My research looks at the ways that Canada and the U.S., along with the bilateral International Joint Commission, have tried to understand and control water in the Great-Lakes St. Lawrence River Basin for well more than a century.
Both countries have made large diversions in and out of the Great Lakes, such as the Chicago Sanitary and Ship Canal, as well as numerous smaller diversions and canals.
In the 1950s, dams along the St. Lawrence transformed this gigantic river into a hydropower pool and navigation channel and, controversially, to help regulate water levels in Lake Ontario. Control works in the St. Marys River partially regulate Lake Superior. Niagara Falls is treated like a tap to generate both hydropower and beauty. Then there is the 100-plus years of perpetually dredging channels and harbours for navigation.
Cumulatively, these anthropogenic interventions have likely changed water levels on the lakes by less than one meter.
Meanwhile, communities have steadily encroached on the water. We turned seasonal sandbars into subdivisions. Metropolises like Toronto and Chicago extended their footprints hundreds of meters into the lake.
And it's not only large dams, diversions and cities that have impacts. Thousands of small individual actions add up, such as the breakwalls, retaining walls and the rip-rap (graded stone or crushed rock) property owners erect to protect boathouses, cottages and other structures.
Collectively, we might be the proverbial fool who built our house on sand — often literally.
These engineered interventions have myriad ecological impacts and unintended consequences, such as invasive species and impaired water quality. They've also instilled a societal hubris that we can — and should — control water on a large scale in the Great Lakes-St. Lawrence system.
High water levels inundate a waterfront home on the St. Lawrence River in May 2017.
However, natural forces — rain, snow, ice cover, temperature, evaporation — are the biggest determinant of water levels in the Great Lakes.
As long as humans have kept records, Great Lakes water levels have oscillated. Depending on which of the Great Lakes one considers, the maximum range of water level fluctuations has been about one to two meters in the past 150 years. For example, very high water occurred in the early 1950s, early 1970s, mid-1980s and mid-1990s.
Now, pushed by a changing climate, the swings in levels that used to take several decades are occurring in half a decade. Instead of a gradual rise and fall, the lakes are going from extreme to extreme.
For example, Lakes Michigan and Huron hit record lows in 2013, and docks on Georgian Bay didn't reach the water. To compensate, the U.S. Army Corps of Engineers proposed putting riffles, basically water speed bumps, on the bottom of Lake Huron's outflow at the St. Clair River.
Now Lake Huron is close to record high levels and docks are under water. If those St. Clair riffles had been installed, the water levels on Lakes Huron and Michigan would be even higher today. This is the type of short-sighted thinking we need to avoid.
Water needs breathing space. We need to move out of the way, rather than try to move water out of our way.
Humans have removed, impaired or destroyed many of the lakes' natural buffers, which accommodate fluctuating water. We've eradicated shoreline wetlands and beaches and covered them with concrete.
If a property along the Great Lakes is getting wet now, it will almost certainly be wetter in the future. While there is some scientific uncertainty about exactly what climate change will do to water levels, the extreme highs and lows will get worse. Volatility is the new normal.
Like climate change, when it comes to addressing Great Lakes levels, the biggest hurdles aren't scientific — they are political, economic and social.
Any new infrastructure along Great Lakes shorelines must be flexible, adaptable and resilient.
But we must also realize that the answer isn't more infrastructure. Infrastructure is too often the cause of our environmental issues.
We need to remove structures entirely and avoid building anything near the water's edge. This will have the added benefit of making more of the Great Lakes accessible to everyone. Since governments zoned vulnerable areas for construction, government funding should be provided.
We should use the opportunity to restore natural shorelines and wetlands. These provide many benefits for both water quality and water quantity. In terms of the latter, they can serve as water retention areas, while wetland plants provide erosion control.
This is all going to be very hard for many people to hear — there will be major resistance. But not moving is going to cost more in the long run. We think we can control water levels, but we need to think differently.
Reposting with permission from our media associate The Conversation.
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The ghoulishly named ogre-faced spider can "hear" with its legs and use that ability to catch insects flying behind it, the study published in Current Biology Thursday concluded.
"Spiders are sensitive to airborne sound," Cornell professor emeritus Dr. Charles Walcott, who was not involved with the study, told the Cornell Chronicle. "That's the big message really."
The net-casting, ogre-faced spider (Deinopis spinosa) has a unique hunting strategy, as study coauthor Cornell University postdoctoral researcher Jay Stafstrom explained in a video.
They hunt only at night using a special kind of web: an A-shaped frame made from non-sticky silk that supports a fuzzy rectangle that they hold with their front forelegs and use to trap prey.
They do this in two ways. In a maneuver called a "forward strike," they pounce down on prey moving beneath them on the ground. This is enabled by their large eyes — the biggest of any spider. These eyes give them 2,000 times the night vision that we have, Science explained.
But the spiders can also perform a move called the "backward strike," Stafstrom explained, in which they reach their legs behind them and catch insects flying through the air.
"So here comes a flying bug and somehow the spider gets information on the sound direction and its distance. The spiders time the 200-millisecond leap if the fly is within its capture zone – much like an over-the-shoulder catch. The spider gets its prey. They're accurate," coauthor Ronald Hoy, the D & D Joslovitz Merksamer Professor in the Department of Neurobiology and Behavior in the College of Arts and Sciences, told the Cornell Chronicle.
What the researchers wanted to understand was how the spiders could tell what was moving behind them when they have no ears.
It isn't a question of peripheral vision. In a 2016 study, the same team blindfolded the spiders and sent them out to hunt, Science explained. This prevented the spiders from making their forward strikes, but they were still able to catch prey using the backwards strike. The researchers thought the spiders were "hearing" their prey with the sensors on the tips of their legs. All spiders have these sensors, but scientists had previously thought they were only able to detect vibrations through surfaces, not sounds in the air.
To test how well the ogre-faced spiders could actually hear, the researchers conducted a two-part experiment.
First, they inserted electrodes into removed spider legs and into the brains of intact spiders. They put the spiders and the legs into a vibration-proof booth and played sounds from two meters (approximately 6.5 feet) away. The spiders and the legs responded to sounds from 100 hertz to 10,000 hertz.
Next, they played the five sounds that had triggered the biggest response to 25 spiders in the wild and 51 spiders in the lab. More than half the spiders did the "backward strike" move when they heard sounds that have a lower frequency similar to insect wing beats. When the higher frequency sounds were played, the spiders did not move. This suggests the higher frequencies may mimic the sounds of predators like birds.
University of Cincinnati spider behavioral ecologist George Uetz told Science that the results were a "surprise" that indicated science has much to learn about spiders as a whole. Because all spiders have these receptors on their legs, it is possible that all spiders can hear. This theory was first put forward by Walcott 60 years ago, but was dismissed at the time, according to the Cornell Chronicle. But studies of other spiders have turned up further evidence since. A 2016 study found that a kind of jumping spider can pick up sonic vibrations in the air.
"We don't know diddly about spiders," Uetz told Science. "They are much more complex than people ever thought they were."
Learning more provides scientists with an opportunity to study their sensory abilities in order to improve technology like bio-sensors, directional microphones and visual processing algorithms, Stafstrom told CNN.
"The point is any understudied, underappreciated group has fascinating lives, even a yucky spider, and we can learn something from it," he told CNN.
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