At stake are millions of dollars, thousands of jobs and a long-accepted way of life. From levels measured one year ago, Lakes Michigan and Huron have slipped 17 inches. Lake Erie set a 30-year record low in July, alarming the scientists and boaters who charted it. It is down by 17 inches. Bordering Metro Detroit, the broad river delta known as Lake St. Clair has dropped 16 inches.
Lake Superior is two inches above last year's level.
Bolstered by recent rains and held back with special gates, Superior's small gains are not enough to compensate for losses in other lakes. As rocks, wrecks and dock pilings break surface beside murky landmarks not glimpsed since the 1960s, lower lakes raise hazards above and below the surface, and are reviving waste chemicals stored within bottom sediments to risk ingestion by fish, birds and people. Warmer weather during the past two winters reduced snowfall over northern lands that feed waters at the system's source, but larger explanations for regional warming are not yet clear. From highs recorded just a year ago, water levels on four of the five Great Lakes have rapidly plunged. Scientists say rises on Lake Superior in July and August can't replace the losses.