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Great Lakes Water Levels
What is the present situation?
Lakes Michigan, Huron and Erie of the Great Lakes system are experiencing the lowest water levels in the past 35 years; from 1997 - 2001, Lakes Michigan and Huron dropped by 3.4 feet, and Lake Erie dropped 3.13 feet.Presently, the lakes are experiencing evaporation and are in their seasonal decline.
Although water supplies to all of the Great Lakes were above average for February 2002, the Lakes remain below average because of a lack of both sufficient ice cover in the Winter of 2002 and sufficient snowmelt in the Spring 2001. These low levels have adversely affected recreational boaters, marinas, commercial navigation and hydropower. The United States Great Lakes Shipping Association reported that for every inch of lost clearance due to low water, an international vessel loses from 90 - 115 metric tons of cargo carrying capacity ranging to $11,000 per day. In the year 2000, Lake Carriers that transport iron ore, coal, grain and other raw cargoes were forced into "light-loading," carrying 5 percent to 8 percent less goods, sending prices higher. Additionally, marinas spent millions to dredge boat slips, channels and harbors along the Great Lakes coasts. Check out the latest water level brochure! (pdf)
How did the water levels get so low?
Present low levels resulted from a combination of lower precipitation, leading to lower runoff, higher evaporation and higher air temperatures during 1997, 1998, 1999, 2000 and 2001 (note: 1998 and 2001 were the first and second hottest years on record globally). Specifically, extremely high air temperatures greatly reduced tributary runoff and increased lake evaporation, particularly on Lake Superior. Additionally, last winter's below average precipitation dramatically reduced the winter snowpack that the lakes depend upon for normal spring rise in lake levels.
This year's Outlook
Predictions from NOAA Climate Outlooks, are for normal precipitation and normal temperatures for March - May 2002. Winter 2002 ice cover on the lakes has been limited to the shorelines and embayments and is well below normal. Additionally, Lake-Effect snows, which normally remove water from the Great Lakes, were prominent in the last two weeks of December 2001 and the first week of January 2002. The predicted average precipitation for the remainder of the winter could possibly create an average snowpack for spring runoff. This, however, will not raise water levels to what they were in the last 35 years.
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Contact: |
Cynthia Sellinger |