Friday, October 19, 2012

Low Water Levels in the Great Lakes

A decade with more drought than flood has left Lakes Michigan and Huron barely above the lowest water level ever recorded there. Warmer than average air temperatures and record-high water temperatures also contribute to the water loss by evaporating water faster from the surface of the lakes. Official forecasts predict that the water level will fall to match the record low through the end of the year, then fall lower for at least the first four months of next year. Then spring rains could begin to lift the water levels. However, such large lakes don’t move very quickly, and it would take years of above-average rains to restore the lakes to historical levels.

The low water levels are more of a worry than an inconvenience at this point, but shipping could be adversely affected if the water levels continued to drop in the coming years. All the Great Lakes are below normal levels. Lake Erie, downstream, is the shallowest of the Great Lakes and could be the first to see obvious changes if water levels continue to fall. Farther downstream, Lake Ontario is at low levels for this time of year. Both of these lakes could fall lower if there is less water coming in from the lakes upstream.