Undercurrents: beneath the obvious

January 10, 2008

The evaporation factor: Warm winter weather + frozen ground = lower lake levels

Filed under: Great Lakes Issues,Lake Levels — nemo @ 12:17 pm

Lake levels continue to decline. This article explains the reasons quite nicely. Notice that average lake temperatures have increased 4 degrees since 1980.

Lake Huron is in a fog, part of a gloomy cycle that’s pushing water levels to record lows, scientists say.

Last week, a winter storm dropped more than a foot of snow over the Great Lakes. Over the weekend, warmer temperatures melted that snow, and much of that water evaporated into the air. The cycle has been playing out for the past 30 years in the Great Lakes, said Cynthia Sellinger, co-author of a paper to be published Tuesday in Environmental Science & Technology, a scientific journal.

Winters have been warmer. Snow doesn’t build up, then seep into the ground and recharge the lakes in the spring.

Instead, warmer winter temperatures melt the snow after it falls, leaving the ground frozen and allowing the snow to evaporate.

“Since 1978, there’s been a long-term decline in precipitation and a long-term increase in evaporation,” said Sellinger, a hydrologist at the Great Lakes Environmental Research Laboratory in Ann Arbor, an arm of the National Oceanic and Atmospheric Administration.

Lakes Huron and Michigan, which are connected by the Straits of Mackinac, are experiencing the lowest water levels in the Great Lakes this month.

Lake Huron is within 2 inches of its all-time low for January, according to data from the U.S. Army Corps of Engineers. The lake is 14 inches lower than it was at this time last year.

It’s projected to dip another inch during the next month, as part of its seasonal decline.

Since 1980, when NOAA temperature buoys were installed, the surface water temperature of Lakes Michigan and Huron has increased by about 4 degrees Fahrenheit, according to Jay Austin, a researcher at the Large Lakes Observatory, part of the University of Minnesota in Duluth.

“It’s larger compared to what we’ve seen in the atmosphere,” or about twice the rise in global air temperatures attributed to global warming, Austin said.

Lake Superior is the only Great Lake seeing higher levels this January. It’s 6 inches higher than at this time last year. The rest of the lakes are 11-16 inches lower than a year ago.

Part of the reason for Lake Superior’s rise is about 10.5 inches of rainfall in the basin during September and October, right at the lake’s low point, said Keith Kompoltowicz, a meteorologist for the Army Corps in Detroit. [From The Bay City Times]

December 6, 2007

Lake Michigan water levels nearly scrape bottom

Filed under: Great Lakes News,Lake Levels — nemo @ 12:51 pm


Signs are mounting that Lake Michigan’s already-low water levels are taking a turn for the worse. The big lake is a foot lower now than it was this time last year. And on Sunday, its level briefly dipped below a record low, according to federal monitoring data.

Water levels are down in wetlands and rivers, environmental experts say, and the latest decline is more bad news for ships, boats and lake and river marinas already suffering from nine years of sinking levels.

November was especially hard on lakes Michigan and Huron, which geologically are considered one lake. Instead of a normal seasonal drop of 2 inches in November, the lakes dropped 6 inches. For the Lake Michigan-Huron watershed, it was the driest November since 1908, according to U.S. Army Corps of Engineers data. Army Corps hydrologists and engineers blame excessive evaporation caused by cold air sucking moisture from the relatively warm lake.

Carl Woodruff, a hydraulic engineer, said it is unusual when evaporation outpaces the water runoff into the two lakes, which happened last month. As a rule of thumb, the two generally match each other over a year’s time.

Dry weather may be only one reason behind the plunging levels.

More than 90 years of historical water-level data suggest the lakes may fluctuate on a 30-year cycle, going from low to low. Lakes Michigan and Huron were low in the mid-1930s, the mid-1960s and began the latest decline in 1998.

Some of the other Great Lakes, particularly Erie and Ontario, have benefited from tropical storms and hurricanes out of the south that brought rain in recent years, including Katrina, Dennis and Arlene.

[From Lake Michigan water levels nearly scrape bottom – mlive.com]

November 21, 2007

Lake levels up for foreseeable future

Filed under: Great Lakes Issues,Lake Levels — nemo @ 12:05 pm
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Good news for Lake Superior comes from this article in the Mining Gazette:

Heavy precipitation will keep Lake Superior’s monthly average water levels out of the record book for the foreseeable future.

“Based on the new forecast we did (this month), it looks like we’re going to stay at least a few inches above the record lows at least until April and that’s due primarily to the rain that fell in September and October,” said Keith Kompoltowicz, a meteorologist with the Army Corps of Engineers Detroit office. However, water levels remain well below average, he said.

“Since the beginning of September the lake rose quite dramatically due to all the rain during the months of September and October the Lake Superior basin received well over 10 inches of rain and the lake level responded by rising quite a bit during that same time frame,” Kompoltowicz said.

June 12, 2007

Lake levels sink, state fears rise

Filed under: Great Lakes News,Lake Levels — nemo @ 11:47 am

The Detroit News:

Lake Superior water levels are headed toward record lows in early fall, a projection that is causing concern about an eventual trickle-down effect in the other Great Lakes as well as Lake St. Clair.

The U.S. Army Corps of Engineers’ June forecast — looking ahead to September and October — predicts Superior’s water level will dip under the record low for that time of the year. That low was set in 1925.

Water levels in lakes Huron, Michigan, St. Clair, Erie and Ontario are all on track to fall below average in early autumn, according to Army Corps estimates.

Lakes Michigan and Huron receive 20 percent to 30 percent of their water from Superior.

At the same time in September that Superior is expected to hit a record low, engineers predict Huron and Michigan will be around 20 inches below normal, roughly at the same point they were last year.

Yet the outflow from Lake Superior into the lower lakes continues to be increased.

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June 1, 2007

Lake Superior outflow increased by another 2% for June

Filed under: Great Lakes News,Lake Levels — nemo @ 7:43 pm

For the second month in a row, Soo Today reports that the outflow from Lake Superior into Lake Michigan-Huron will be increased although Lake Superior and Lakes Michigan-Huron continue to be well below their long-term averages for May:

The International Lake Superior Board of Control, under authority granted to it by the International Joint Commission, has set the Lake Superior outflow to 1,530 cubic metres per second (m3/s) (54.0 thousand cubic feet per second (tcfs)) for the month of June.

This is the outflow recommended by the regulation plan for the month of June and is an increase from the May outflow, which was 1,500 m3/s (53.0 tcfs).

Currently, the Lake Superior level is about 53 cm (21 inches) below its long-term average beginning-of-June level, and is 40 cm (16 inches) below the level recorded a year ago.

This past month the level of Lake Superior rose 3 cm (1 inch), while on average it rises by 10 cm (4 inches) in May.

The level of Lakes Michigan-Huron is now about 47 cm (18 inches) below its long-term average beginning-of-June level but is 8 cm (3 inches) lower than it was a year ago.

The May outflow increase was almost 9% while the International Joint Commission (IJC) proposes a study of water levels and near-historic lows in Lake Superior are turning the largest coastal wetland in the Great Lakes into dry land.

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May 7, 2007

Increased Outflow from Lake Superior Despite Record Low Water Levels

Filed under: Great Lakes Issues,Lake Levels,Michigan — nemo @ 12:25 pm

As it has for several months running, Lake Superior’s water level stood at 18 inches below its monthly average for early May and 13 inches below its level at the same time last year. Even so, The Soo Evening News reports that the Army Corps of Engineers has increased the outflow from Lake Superior by almost 9%:

Amid growing accounts of low water worries from around Lake Superior, the Corps of Engineers announced this week that water released to the lower Great Lakes increased by 4,300 cubic feet per second (cfs) at the start of May.

The May increase in water released to the lower St. Marys River was apparently called for in the International Lake Superior Board of Control regulation plan for Lake Superior. The increase accompanies a slight seasonal rise in Lake Superior water levels last month.

In the announcement, the Corps said water released to the lower St. Marys increased from 48,700 cfs to 53,000 cfs for the month of May.

The statement said Lake Superior’s water level is expected to rise again in May, despite continued near-drought conditions across the Big Lake’s watershed.

The Corps reported water supply to all three Upper Great Lakes was below average in April.

Lake Superior remains below chart datum and just a few inches above its long-term record set in 1926. Water levels took a plunge late in 2006 due to widespread dry conditions across its watershed last summer. Relatively light winter snow pack provided only limited relief as the spring thaw set in by March.

Lakes Huron and Michigan rose in April by about two inches, or half the two lakes’ normal April rise. Like Superior, the two lakes stood at 16 inches below their average level for early May when this month began, the Corps of Engineers reported.

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April 26, 2007

Near-historic lows in Lake Superior are turning the largest coastal wetland in the Great Lakes into dry land

Filed under: Great Lakes Issues,Great Lakes News,Lake Levels — nemo @ 4:55 pm

BadriverFrom The Daily Press – Ashland, WI:

Near-historic lows in Lake Superior, along with years of drought inland, are turning the Kakagon Sloughs, the largest coastal wetland in the Great Lakes, into dry land.

The level in Lake Superior so far in April is 182.86 meters, according to the National Oceanic and Atmospheric Administration, compared with the historic low of 182.69 meters, set in 1926. That is a difference of about 6 inches, and between one and two feet lower than 2006.

… particularly vulnerable in the sloughs of Bad River is the harvest from one of the largest wild rice beds in the world.

As water recedes from banks of the channels, wild rice bushes are by no means the lone victims. Lower water levels also reduce habitat for the young fry and fingerlings of walleye, perch and pike, among other species, forcing all aquatic life to live with less elbow room (and hiding space) in a more narrow channel.

Further inland, the drought is also having an impact on lakes and streams that never touch Lake Superior, as low levels that lead to warmer temperatures could have a lasting impact on aquatic life.

“I don’t think, right now, we’re in a crisis situation on the inland lakes,” said Cristopher Sand, a fisheries biologist for the DNR who studies inland waters in Bayfield and Douglas counties. “But, given the lack of precipitation over the decade and higher air temperatures, there is cause for concern that our fish communities may change as a result.”

Precipitation necessary for Lake Superior, along with evaporation that draws water from it, is just as vital for “seepage” lakes inland that have no inlet or outlet, Sand said.

Warmer temperatures without the corresponding rain dry up not only lakes, Sand said, but other areas like the Bibon swamp, which is fed by the White River.

Barring a monsoon that dumps buckets of water on the region, it could take years of steady precipitation if levels are to return to normal.

Officially, the lake is about 18 inches below normal, and more than a foot below the level at this time last spring. In March, the lake came within a few inches of reaching the all-time record low set in 1926.

As it does every April, the lake level is moving up. But it’s not going up as much as usual. It’s possible the lake could set monthly low records this summer if rainfall across the lake’s watershed doesn’t increase.

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March 13, 2007

Great Lakes levels plunge in February

Filed under: Great Lakes News,Lake Levels — nemo @ 8:16 pm

The Muskegon Chronicle carries this update on lake levels in February:

Water levels in Lake Michigan and Lake Huron dropped six times faster than average in February, a startling plunge that one expert attributed to the region’s increasingly bizarre winter weather.

The lakes’ water level dropped three inches in February, according to the latest data from the U.S. Army Corps of Engineers. On average, the water level in lakes Michigan and Huron — which are technically one body of water — drops a half-inch in February, according to data the Corps of Engineers has tracked over the past century.

The lakes are currently 16 inches below their long-term average for early March, according to federal data. Great Lakes water levels typically fall in the winter and rise in the spring, after the snow melts.

Water levels have dropped nearly four feet in Lake Michigan since 1998. That change is significant because lower lake levels drive up the cost of shipping and can make recreational boating more dangerous.

For each one-inch drop in Great Lakes water levels, freighters have to reduce their cargo by 50 to 270 tons to avoid running aground in shallow channels and harbors, said Glen Nekvasil, a spokesman for the Cleveland-based Lake Carriers Association.

Lake Superior’s water level fell four inches in February, twice the average decline in winter. The lake is close to its lowest water level ever, recorded in 1926, said Carl Woodruff, a hydraulic engineer at the Corps’ Detroit office.

Several factors contribute to lower lake levels:

  • Above-average summer water temperatures kept the lake warmer during the following winters.
  • Milder winters reduced ice cover on the lakes, which increased water evaporation during the winter.
  • Warm lake water is more susceptible to evaporation during the cold winter months.
  • When dry, cold air flows over the lake in the winter, it draws more moisture out of the relatively warm water and triggers larger lake-effect snow showers.
  • When snow melts before the ground thaws, most of the water evaporates and is lost. Under normal conditions, snow melts slowly in late March and April, is absorbed into the ground and slowly flows back into the lake.
  • Drought conditions in northern Wisconsin and the western half of the Lake Superior drainage basin also have contributed to lower lake levels in the last couple of years, according to Corps of Engineers officials.

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