Great Lakes Article:

Lake Levels Dropping; Is Drain Hole Near Detroit The Problem?
By Jay Sorgi
620wtmj.com (620AM - Milwaukee)
Posted October 19, 2007

The Great Lakes, including Lake Michigan, are losing water, and the federal governments of the U.S. and Canada are trying to figure out why.

Lake Superior's water level is three inches away from its record low for October, and Lake Michigan and Lake Huron stands seven inches away from its October record low water level. 

The theory is that erosion has been happening for around 40 years at the bottom of the Saint Clair River near Detroit. 

That has caused what's essentially a drain hole around Lake Huron which ends at the Saint Clair River, and that Lake Michigan and Lake Huron's water levels have plummeted at a rate of 2,500,000 billion gallons every day. 

The Journal Sentinel says that if that's the case, the U.S. and Canada could put a flow control mechanism on the bottom of the Saint Clair.  That could possibly rise the water levels back to normal.