Falling lake level raises harbor havoc.(Lake Michigan)

The sounds of summer along Lake Michigan beaches are changing.

Waves sloshing, children playing, birds singing and boomboxes blaring are joined by propellers smashing and keels ripping.

A combination of lower precipitation in the Great Lakes drainage basin and higher temperatures in recent years is causing water levels in Lake Michigan and all of the Great Lakes to fall.

Boats of all sizes - in-board motorboats, sailboats and cargo vessels - are exercising more caution in the harbors and marinas, watching for lake bottoms that were not a problem in recent years.

"Lake Michigan is down two feet from last summer," said Philip Keillor, a researcher at the Sea Grant Institute at the University of Wisconsin-Madison.

Don't be fooled by higher-than-average 1999 rainfall in southeastern Wisconsin filling Lake Michigan. The Great Lakes drainage basin is predominantly influenced by rain and snowfall occurring in the northern reaches o f …