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Saturday, 04 August 2018 00:07

State of Flux: Great Lakes water level variability leads to uncertainty for coastal areas

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High water levels on Lake Michigan have reduced the amount of beach available to tourists, and have caused some damage at municipal-owned properties in high-erosion zones, according to Ottawa County Parks and Recreation Director John Scholtz. At Ottawa County’s Rosy Mound Natural Area south of Grand Haven, shown here, the high water has led to some access point closures this summer. High water levels on Lake Michigan have reduced the amount of beach available to tourists, and have caused some damage at municipal-owned properties in high-erosion zones, according to Ottawa County Parks and Recreation Director John Scholtz. At Ottawa County’s Rosy Mound Natural Area south of Grand Haven, shown here, the high water has led to some access point closures this summer. PHOTO: MARK SANCHEZ

 

Fluctuating water levels remain a fact of life along the West Michigan coast and for inland lakes.

As recently as 2013, historically low Lake Michigan levels meant larger beach areas and less erosion, but also more difficulty for boats to navigate to area ports. Today, with levels on the rise, beach areas have shrunk and erosion threatens properties along the lakes, all while shippers say commerce now operates more efficiently.

Who benefits as Great Lakes water levels shift will always be a case of competing interests. But a combination of natural and non-natural factors may be causing faster fluctuations between low and high levels, which creates unpredictability for everyone. The two-year increase after the historic low in 2013, for example, was the fastest ever recorded in Lakes Michigan, Superior and Huron. It followed a relatively stable 15-year period of low water levels.

“It’s a really stark contrast to what people had been used to the previous 15 years,” said Drew Gronewold, hydrologist at the National Oceanic and Atmospheric Administration’s Great Lakes Environmental Research Laboratory in Ann Arbor. “The contrast of a static condition and then a sudden change in variability can create a lot of problems.”

Some of the current problems range from property loss or damage related to erosion along the coasts and connected inland waterways to greater congestion at beaches as the water levels inch ever higher, possibly affecting the tourism economy.

Scientists say it’s too early to make a direct correlation between water levels — which depend on a complex relationship between precipitation, evaporation and runoff — and climate change, although it could become a factor in the coming decades.

Unlike U.S. marine coastal areas, which generally are preparing for sea level rise related to climate change, the Great Lakes are a “completely different story” riddled with high variability, Gronewold said.

As well, this variability comes amid competing interests between sectors of the West Michigan economy.

“Shoreline people want lower levels, environmental people want fluctuations, and navigation people want high levels. You can’t make everyone happy under those circumstances,” said Al Steinman, director of Grand Valley State University’s Robert B. Annis Water Resources Institute in Muskegon.

Human element

Federal and university researchers are closely watching these water level fluctuations on the Great Lakes. A July 13 story in the Chicago Tribune highlighted concerns among some coastal residents about increased outflows from Lake Superior through the St. Mary’s River as water levels already are increasing downstream in Lakes Huron and Michigan.

The International Lake Superior Board of Control manages Lake Superior levels by controlling the outflows and effectively deciding which interests take precedence over others. At the top of its considerations are navigation and hydroelectric dams along the St. Mary’s River that require certain water levels, according to the U.S. Army Corps of Engineers.

According to the report, Lake Superior outflows last year were the highest they’ve been in 32 years. Still, researchers interviewed for this story say that natural weather and climate patterns influence water levels far more than humans’ control over outflows.

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Missy Kropfreiter, a hydraulic engineer at the Army Corps’ Detroit office, emphasizes that “water levels are controlled by natural factors, which are the biggest player in water level changes.”

The Army Corps’ Detroit office acts as a repository for data on Great Lakes water levels and works directly with boards overseen by the International Joint Commission. Kropfreiter disagrees with claims that outflows from Lake Superior are exacerbating high water levels and erosion in Lakes Michigan and Huron.

“Those issues are primarily from extra precipitation we have seen over the past several years. There’s just a lot of water in the system,” she said.

Kropfreiter added that the official data set on water levels is roughly 100 years old, which is not a large enough sample size to determine whether fluctuations are getting more intense.

“We can’t make any predictions or glean any variability at this point,” she said, adding that studies on the role of climate change are “ongoing.”

The lows and the highs

Kathy Evans, environmental program manager with the West Michigan Shoreline Regional Development Commission, recounts several examples of damage along the shoreline of Muskegon Lake — which is connected to Lake Michigan via the Muskegon River channel — as Great Lakes levels have increased the past few years. That includes issues at the city’s Heritage Landing park and at the USS LST 393 Museum, which she said had come loose from its moorings. Seawalls, docks and other coastal infrastructure have been damaged from erosion.

“Some of that will heal on its own,” Evans said. “That’s the sort of thing that’s happening more and more.”

WMSRDC has been involved with habitat restoration projects to help mitigate water damage and wave impacts during high-level times. “Softening shorelines” also includes making sure structures aren’t built in low areas.

“Most of our work is on resiliency,” Evans said. “One thing people need to think about is infrastructure in the future not being quite so close to the shoreline. So far, we’re seeing a lot of damage with that. The pattern seems to be changing and it’s getting more difficult to predict the future.”

Kathleen Torresen, president of Torresen Marine Inc. on the western end of Muskegon Lake, sees the challenges with both high and low water levels. Low levels require more dredging in order to use boat slips.

“Higher water levels are really great for boating overall, but it’s very tough on solid structures that are there,” Torresen said. This year, high winds and large waves washed out a section of sea wall at the marina, she added.

“Everyone has their fingers crossed we’ll come off this peak and go back down — 6 to 8 inches even would make a huge difference,” she said.

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Torresen Marine President Kathleen Torresen said the recent run of high water levels on Lake Michigan and its connected waterways have been good news for boaters, but hard on infrastructure at the marina on Muskegon Lake, where high winds and large waves washed out a section of sea wall earlier this year. PHOTO: KATY BATDORFF

To the south, Ottawa County Parks and Recreation Director John Scholtz said the current levels “really negatively impact our beach experience for our park visitors. The beaches get a lot smaller and it cuts down on our capacity.”

Several county-owned sites are in high-risk erosion areas, Scholtz said. Other than removing staircases and altering paths toward the beaches, “there’s really nothing we can do about it,” he added. “It’s a pretty powerful force.”

Alternatively, Great Lakes shippers benefit from high water levels. According to the Cleveland-based Lake Carriers’ Association, vessels can hold about 270 tons more of iron ore for each additional inch of lake water.

“Higher water levels at least through portions of the lakes and connecting channels helps us,” said Thomas Rayburn, director of environmental and regulatory affairs for the Lake Carriers’ Association.

Elevated water levels also help vessels navigate ports that might otherwise have to be dredged, particularly near Detroit and Toledo. Still, traffic declined in West Michigan for the association’s members after Consumers Energy closed the B.C. Cobb power plant, ending the need for coal shipments into Muskegon Lake.

“It’s about accessibility to docks. With lower water, the less we carry and the less efficient the system is,” Rayburn said. “We have nine and a half months to deliver 12 months of materials to our customers. Every inch of water and every day that is ice-free in our channels is important to us and our customers.”

Bob Lukens, community development director for Muskegon County, said lower water levels often are “more devastating than higher levels.” Particularly, low levels can inhibit ship passage through Muskegon’s harbor, which qualifies for U.S. Army Corps of Engineering dredging — and federal funding — if shipping tonnage crosses a 1 million ton threshold.

“It’s important for us to maintain those lake levels for commerce and industry,” Lukens said.

Unpredictability and climate change

At NOAA, Gronewold said Great Lakes water levels fluctuate because of natural occurrences and over varying degrees of time, such as hours or days, month-to-month, and every two to five years. Monthly changes occur because of precipitation, evaporation and runoff from streams and rivers.

“When we have a change in water levels over a two- to five-year period, as we did starting in 2013, those are usually due to a consistent anomaly,” Gronewold said. In this case, it’s related to above-average precipitation.

A large portion of evaporation occurs in the winter months. Although two harsh winters following 2013 created more ice coverage and hindered evaporation, the Great Lakes region is trending toward milder winters, noted Jeff Andresen, a Michigan State University geographer who has served as the state’s climatologist.

Meanwhile, Michigan and the rest of the Great Lakes basin have had more precipitation and are becoming “significantly wetter just in the last 50 years,” Andresen said. In the longer term, the tracking of evaporation trends is becoming more complicated, he added.

“There certainly is a climatic link to this,” Andresen said. “It’s much more complicated to deal with or respond to changes in variability rather than the mean. If things slowly change, that’s one thing, and sometimes you can engineer an adequate solution. Variability is much more difficult.”

Gronewold echoed Kropfreiter’s point about the lack of historical data to attribute specific trends to climate change, at least at this point. Additionally, there isn’t a clear link to the net impact to water levels if both precipitation and evaporation increase, he said.

“There’s a subtle energy between those two forces that makes it hard to say levels will strictly go up,” Gronewold said.

As well, GVSU’s Steinman points out that Lake Michigan remains below its all-time high water levels set in 1986.

“There are two main factors to think about: Memories of humans are very short-term, and water levels have been going up and down for millennia. The reality is we need to be patient,” he said. “The second factor is Mother Nature is really controlling this no matter what humans want to do. We’re only tweaking the edges of this.”

However, Steinman says there are “huge economic implications” with water levels that impact various sectors differently.

“Every sector of our society is going to be impacted by water levels, but not in the same direction,” he said. “That’s why it’s so complicated and difficult. It’s a policy issue, not a science issue.”

While it may be difficult to determine long-term trends for the lakes, the recent shift from low to high levels causes concern, if only for the predictability that lies ahead. The Carriers’ Association’s Rayburn described the most recent shift since 2013 as “crazy.”

Torresen echoes his surprise.

“If you had told me (in 2013) that we’d be close to an all-time high by now, I would have scoffed,” she said. “We think we can predict, but really we don’t know.”

Read 2831 times Last modified on Sunday, 05 August 2018 20:37

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