Great Lakes water levels likely to rise into 2020
Sep 12, 2019 11:07AM
Waves over a seawall in the St. Claire River. Photo: Jim Bloh
By Jim Bloch For MediaNews Group - September 11, 2019
You may have to endure continued high water and even higher water into next year.
That was one of the takeaways from a public forum on lake levels conducted by representatives of the U.S. Army Corps of Engineers, the National Oceanic and Atmospheric Administration, Michigan Department of Environment, Great Lakes and Energy and the University of Michigan in Port Huron Sept. 5.
"This is a Great Lakes-wide issue," said Keith Kompoltowicz, the chief watershed hydrologist for the USACE Detroit.
What will it take to bring water levels down?
A cool dry fall, a warm and relatively snowless winter and a warm dry spring, said Kompoltowicz.
The audience —more than 100 people in the Donald Dodge Auditorium in the St. Clair County Building — laughed, the kind of laugh that defines "gallows humor."
Not that such weather patterns are unheard of — they characterized the falls through springs of 1976-1977 and 1998-1999. They generally characterized the 15-year period and contributed to the all-time record-low water levels for Lake Michigan-Huron in January of 2013. Global warming also helped, boosting the surface temperatures of Lake Superior and Huron by 2 degrees Fahrenheit and increasing evaporation by 30% per year.
Since that time, however, the weather has been wet. The lakes have risen 6 feet in the past six-plus years.
By January 2015, lake levels had experienced their largest 24-month rise in recorded history — the Corps' data bank goes back a century to 1918.
June 2018 to May 2019 was the third-wettest year on record for Michigan, said Rich Pollman, a meteorologist with NOAA's National Weather Service in White Lake. January 2014 to January 2017 was the wettest three-year period on record; January 2014 to 2019 was the wettest five-year period on record.
This year, a number of the Great Lakes set records for high water.
Lakes Superior, St. Clair and Erie set all-time monthly mean highs in May; in June and July, all three, plus Lake Ontario, set records; in August, Lake Superior tied its all-time high, and Lakes St. Clair and Erie set records.
The USACE's official forecast extends out six months.
"The forecast is for higher water levels than last year through 2019 and early 2020," said Kompoltowicz.
From Pollman's point of view, the forecast is for "neutral" conditions through next spring, but he noted that neutral forecasts have sometimes been associated with "our worst winters."
And he said there's a better chance of a warm fall than a cool fall, which would put a brake on evaporation from the lakes and could contribute to higher water levels.
In the end, however, "what really drives our weather can only be forecast one month out," said Pollman.
Shorelines moving inland
The long-term bad news for people who own homes and businesses on the Great Lakes' 14,000 miles of waterfront is that "the shorelines are gradually moving inland over time," said Richard Norton, a lawyer and professor at the Taubman College of Architecture and Urban Planning at U-M.
Michigan is home to the longest freshwater shoreline in the country and the state contains 62 percent of the shoreline of the Great Lakes.
The lakes have always been characterized by a cycle of high and low water levels, often separated by 20 or 30 years. Some climate researchers, such as Drew Gronewold and Richard B. Hood, both at U-M, suspect that cycle is getting shorter as land, water and air temperatures increase; neither were at the forum.
"The highs are going to get higher and the lows are going to get lower," Norton said.
During high water periods, the lakes chew away at the beaches, especially during storms. Norton said that erosion was the predominant feature of high-water periods.
"It's a remorseless process," Norton said.
When lake levels fall, the shorelines get a reprieve. But a shorter high-low cycle featuring more extreme high water marks would hasten the retreat of the shorelines.
"Nature is going to win," Norton said.
Seawalls are unlikely to provide long-term protection. Seawalls starve the beach of replenishing sand and contribute to the loss of beachfront, Norton said.
Local governments should plan for radical changes in lake levels, including redrafting zoning requirements.
More than 300 local units of government touch on rivers or lakes in Michigan, but 75% have no plans to deal with fluctuating lake levels — known as resiliency planning.
The Blue Water Area provides some of the best boating and water recreation in the country, maybe the world, said Jerry Johnson, director of the five-county District 5 for Michigan State University Extension. "But this has been a challenging year."
There may be more to come.
Jim Bloch is a freelance writer. Contact him at [email protected].
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