Looks like the highs for the lake were in 1983 at 1225 feet and lows in 2010 at 1081 feet. Difference of 144 feet. The drop in feet doesn't tell the entire story. Lakes aren't square tanks or equal depth from all edges.
Perspective.
1983 water acre feet 26,864,000
2010 water acre feet 9,932,000
1983 gallons 8,752,000,000,000
2010 gallons 3,236,000,000,000
That's a 63% drop in total available gallons in just 27 years.
We only do government crisis by crisis. Because we have no real leadership, just leadership theater. Water crisis is around the corner.
Then you read about how Nestle and other companies have bought all kinds of land next to the great lakes and through techniques that siphon water from the lakes bottle it and send it around the world. Does Nestle pay anything to fund the water infrastructure? Nope not a dime that's all on us.
Great site. ->
http://www.water-data.com/