PELLSTON — Over the past decade, Douglas Lake in northern Michigan has experienced variable water levels, much like the Great Lakes.
Experts at the University of Michigan Biological Station along Douglas Lake say that, overall, lake levels have been high for years but showed an “unusually rapid decline” during this summer’s hot, dry weather.
“Although our current low lake levels on Douglas Lake are not record lows, the rate of decline in lake levels this year was more rapid than usual,” said Dr. John Lenters, senior research specialist at UMBS who studies the effects of weather and climate on water resources, particularly the physical aspects of lakes such as water temperature, ice cover, evaporation and lake levels.
Scientists at UMBS, the more than 10,000-acre research and teaching campus in northern Michigan just south of the Mackinac Bridge, have collected a variety of data on Douglas Lake levels for a century.
“The period of high waters might be over for now,” said Adam Schubel, resident biologist at UMBS, who takes measurements at the Stockard Lakeside Lab boat well.
The lake level is 712.25 feet above sea level, which is only about two inches below the average for the month of September, but it's also the lowest water level researchers have seen since 2012.
Schubel said the level of Douglas Lake usually swings about 1.5 feet annually between the high and low.
On average, lake levels tend to show two peaks per year, once in late spring and another in mid-winter. The spring peak occurs mostly as a result of snowmelt, but also because of increasing rainfall during a time period when lake evaporation is still low. Similarly, the winter peak follows higher autumn precipitation and low evaporation. Both of these seasonal patterns are typical for the climate of northern Michigan.
For example, Douglas Lake measured 714.65 feet above sea level on May 7 of this year, around the time of the spring peak. On August 10, 2023, it had dropped over two feet to 712.43 feet.
“We had a pretty high spring peak in 2023 due to lots of snowmelt and spring rain,” Lenters said.
According to National Weather Service data collected at the Pellston airport, the Douglas Lake area experienced above-normal precipitation in the spring, followed by below-normal precipitation after that — and below-normal precipitation overall for this year.
“This matches what we’re seeing in the lake level data — an above-normal rise in the spring and more-rapid-than-normal decline in the summer,” Lenters said.
Air temperature data show that Pellston had quite a few periods of above-normal temperatures too, including a few that bump up against or set new records.
The September record, since 1980, was 94 degrees on Tuesday, September 5, 2023. That was one degree above the previous record of 93 degrees recorded on September 5, 1999.
Temperatures also reached an unusually warm 80 degrees or higher for a few days in April. Ice out in South Fishtail Bay occurred on April 13, two days earlier than the average.
“The high temperatures in mid-April may have contributed to the slightly earlier ice-off we saw on Douglas Lake,” Lenters said, “and the warm temperatures since then likely led to higher-than-normal lake evaporation rates this summer, once the lake got really warm. Together with the below-normal precipitation, these would both lead to the rapid drop in lake levels that we’ve seen in 2023.”
The lowest recorded lake level in the UMBS records is 710.79 feet above sea level in October of 1955. The highest recorded lake level was 714.95 feet recorded on May 6, 2018.
The recent record-high levels have caused significant erosion and essentially nibbled away at the nearshore habitat.
“As the lake levels have declined, they've exposed an exceptionally large beach area,” Schubel said. “We've seen a similar pattern on the Great Lakes in recent years, which has vastly increased shoreline beach habitat. That’s good news for organisms that favor those conditions, like Piping Plovers on the Great Lakes or Spotted Sandpipers on Douglas Lake.”