level plunging near record
By Eric Carlson
The Leelanau Enterprise
Lake Michigan water levels were reaching their seasonal
peak this week and were expected to remain steady through
the month of July, according to the Army Corps of Engineers.
However, water in the Lake Michigan-Huron basin is a
full 13 inches below last year’s level at this time, and
24 inches below its long term average.
Harbormasters at Leelanau County’s municipal marinas
have reported that lower water levels haven’t been much
of a problem so far this year. Most marinas in the county
have been dredged within the past two years.
However, projections provided this week by the Army Corps
of Engineers show that water levels could close in on
their all-time low later this year.
Generally, Lake Michigan water levels begin an annual
decline around August and reach a low point around March.
The Army’s projections extend into December 2003, when
levels could come within two inches of an all-time low
recorded in 1964.
The most likely scenario, however, is that water levels
will dip to within about five inches of the all time low,
according to the Corps’ projection.
Currently, water levels in Lake Michigan are some nine
inches above the 1964 low. In fact, the water is almost
exactly at its "chart datum" level - the level
at which most nautical charts depict water depth. The
"chart datum" level is 577.5 feet above sea
level for the Lake Michigan-Huron basin.
Elsewhere in the Great Lakes, Lake Superior water is
12 inches below its long-term average level. Lakes St.
Clair and Erie are 12 and 16 inches below averages, respectively.
Lake Ontario’s level, on the other hand, is four inches
above the long-term average. However, all of the Great
Lakes, including Lake Ontario, are below last year’s level.
Lake Superior’s water level is forecasted to continue
its seasonal rise in the next four weeks. While Lake Michigan
and Huron are reaching their seasonal plateau, Lakes St.
Clair, Erie and Ontario are already into their seasonal
Part of that fluctuation is related to flows through
channels connecting the lakes, according to the Army Corps.
The Lake Superior outflow through the St. Mary’s River
into Lake Huron is expected to be below average during
the month of July. Flows in the St. Clair and Detroit
Rivers are also expected to be below average, while flows
in the Niagara and St. Lawrence Rivers are expected to
be near average in July.
Fluctuating water levels are also related to the amount
of ice that forms on the lakes over the winter. Although
heavy ice was reported on the Great Lakes this winter,
it was not enough to significantly affect the amount of
water that evaporated from the lakes.
More significantly, the overall amount of precipitation
in the Great Lakes region has been relatively low this
Plenty of rain has fallen downstate recently, but very
little has fallen on northwestern lower Michigan over
the past several weeks.
Although the current near-drought conditions in the northern
lower peninsula may benefit from projected rain, the amounts
of precipitation forecast almost certainly won’t be enough
to affect lake water levels.
According to the National Weather Service, a 60-percent
chance of rain was expected Wednesday evening. For today,
Thursday, the forecast called for another 60-percent chance
of isolated thunderstorms with scattered showers overnight.
Temperatures were expected to remain relatively mild,
with highs around 70 through Friday. Another chance of
showers was expected Friday, with the sky clearing on
Partly cloudy skies were forecast for Sunday, with temperatures
rising. The forecast for Monday called for another day
of partly cloudy skies and high temperatures around 77
Another chance for rain may emerge on Tuesday, according
to the National Weather Service forecast.