NOAA PROJECTS LAKE SUPERIOR MAY HIT RECORD LOW LEVELS THIS FALL
August 16, 2007 — NOAA hydrologists indicate that Lake Superior is nearing record lows for the month of August, a trend that if continued could break past record lows for the months of September and October. NOAA’s Great Lakes Environmental Research Laboratory is able to forecast lake levels 12 months in advance using current hydrological conditions combined with NOAA’s long-term climate outlooks.
Superior is less than six centimeters higher than its August record
low of 182.97 meters which was set in 1926, and it looks as though the
water levels may continue to plunge," said Cynthia
Sellinger, deputy director of NOAA's Great Lakes Environmental Research
Laboratory in Ann Arbor, Mich. "NOAA's lake level forecasts predict
that there is a 15 to 20 percent probability that new monthly records
will be set sometime this fall."
Lake Superior’s record low of 182.69 meters was set in April 1926, the same year the lake reached an averaged annual record low of 182.90 meters as a result of a major climatic event that led to the dust bowl. Sellinger said that dramatic water level changes are generally caused by major climatic events. This includes the record high lake levels in the 1980s because of extreme rainfall, as well as the most recent drop in lake levels that were partially caused by the strong La Niña event in 1998 that affected the jet stream through the Great Lakes area and led to extreme droughts.
Anthropogenic causes could contribute to lower water levels as well. Canals and rivers are often dredged in the Great Lakes basin to allow large cargo ships to pass. As rivers are dredged, the channels for water to flow out of the Great Lakes basin are broadened, allowing for more water to run out.
Lower water levels mean more dredging and less cargo for the shipping industries that rely on the Great Lakes waterway as an essential route from Africa, Europe, and Asia to ports like Montreal, Detroit, and Duluth. On average, for every inch of low water levels, cargo ships must reduce their load by 50 to 270 tons, therefore providing less cargo for the same amount of shipping time. The economic impact of reduced cargo capacity eventually trickles down to consumers.
The estimated Great Lakes $16 billion recreation boating industry and the $4 billion sports fishing industry have also felt the effects of lower water levels. With marinas either dredging, relocating, or closing down completely, boaters are having a hard time launching boats, as well as navigating shallow waters and trying to use docks that were built when water levels were two feet higher.
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Jana Goldman, NOAA Research, (301) 734-1123