Great Lakes Approaching Or At Record Lows; Falling Now For 15 Years
DULUTH, Minn. — When the American Century cargo ship glides beneath the Aerial Lift Bridge into Duluth, dock workers will spring to action, ready to load it with coal. But when the 1,000-foot "laker" departs, its holds won't be full. Before workers can fully load the ship, it must first clear a shallow spot in the St. Mary's River after passing through the Soo Locks. The river connects Lake Superior to Lake Huron, which is at record low levels.
"They have to make sure they have enough under-keel clearance to pass over this rock section without doing damage to their ship," said Adolph Ojard, executive director of the Duluth Seaway Port Authority. "So they can't load any deeper."
Lake Superior also is low -- about a foot below its long-term average. But Lake Michigan and Lake Huron are even lower, nearly two feet below their averages. Their water levels have fallen for 15 years, the result of declining rainfall on the lakes, and increasing evaporation.
That's expected to significantly affect the economy of the Great Lakes region because even one inch of water makes a big difference for huge ships like the American Century. "On your thousand-foot ships, an inch of water is over 260 tons," Ojard said. "So if you multiply that times the freight rate, then the fact that ship makes 45 trips a year, all of a sudden we see almost an entire cargo in that ship, one entire trip being consumed in the reduced draft."
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http://minnesota.publicradio.org/display/web/2013/04/23/environment/great-lakes-water-levels-reaching-record-lows
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