Lake Superior Water Level
Lake Superior's November water levels are at 80 year lows, sparking concerns that the rapid fall of the world's largest freshwater lake could hurt shipping, shorelines and fish populations. The drop in levels is due mainly to six months of drought in the region. But the affects could last years, and continued dry conditions could create further problems.
In the shipping business lower water levels mean the freighters that carry iron ore, coal and limestone must take on lighter loads in order to navigate through locks, channels and harbors.
The combination of receding lake water and lack of runoff has let sandbars form in the mouths of small feeder streams. That cuts off trout and salmons from their spawning beds and potentially reducing future populations.
At the Apostle Islands National Lakeshore, some docks are now so high above water that they'll be fitted with extra guards next spring to keep boats from sliding under them. Park officials might also dredge some bays ahead of schedule to maintain boat access.
Fluctuations in the Great Lakes are normal. Lake Superior normally oscillates 1 foot in a normal year, and has varied 4 feet in more than a century of record keeping.
But this year, instead of rising through the spring and summer as has been customary, the lake plummeted from near normal levels last spring to almost a foot below normal in the fall — hitting its lowest level since November 1925.
The U.S. Army Corps of Engineers predicts the lake will drop another 3 inches in the next three weeks, and it may drop 5 inches or more by the end of February.
Lack of rain fall makes the lake more prone to evaporation. With its size preventing significant ice cover; the dry area that comes with colder temperatures makes the lake lose more water to evaporation in the winter. If the drought continues into next year, Lake Superior could drop to its lowest recorded level ever.
December 4, 2006 6:47 AM | Category: Lake Superior