One of Michigan’s recurring public concerns during the past quarter-century is the possibility that politically powerful arid regions could take so much Great Lakes water that the lakes would be irreparably diminished. One prominent response to this anxiety is Gov. Jennifer Granholm’s proposed Water Legacy Act, which would impose a permit system on much of the state’s agricultural, utility and business water use.

Proponents of heavy-handed water regulation, whether under the governor’s proposal or the 1985 Great Lakes Charter, have a rhetorical advantage. The usage thresholds they propose that would trigger government control always sound huge — 100,000 gallons per day, or a million gallons per day.

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But let’s put these figures in perspective. Actually, they are not so large.

Consider a 15-acre plot — about the size of a small country cemetery. Sprinklers apply a quarter inch of water on the parched grass.

That’s 100,000 gallons.

Suppose you’re lazing on the bank of a creek that’s 20 feet across and two feet deep and moseys along at one mile per hour. You nap for 45 minutes. While you were asleep, a million gallons of water passed by.

Relatively small rivers contain stupendous volumes of water. The Huron River flowed through Ann Arbor last Sunday[1] at a rate of about 4,400 gallons per second — meaning 263,000 gallons per minute, or nearly 16 million gallons an hour. In East Lansing last Tuesday morning,[2] the flow of the shallow, little Red Cedar was about 2,100 gallons per second, or 100,000 gallons per 48 seconds, or more than 7.5 million gallons per hour.

Bigger rivers are staggering. The Grand River at Grand Rapids last Tuesday[3] was moving a million gallons in less than 17 seconds. That day, more than 5 billion gallons of water passed through the city.

The vastness of the natural hydrologic system is further emphasized by precipitation. Mid-January’s flooding rains amounted to well over an inch of water in portions of the state. Then the crippling Jan. 22 snowstorm added up to a half-inch of liquid. Two inches of precipitation across half the Lower Peninsula total about 700 billion — not million, but billion — gallons.

The Great Lakes reflect precipitation abundances. The Army Corps of Engineers reports Lake Michigan and Lake Huron are more than 9 inches higher than a year ago. Nine inches of water in those two lakes equal about 7 trillion gallons of lake water that wasn’t in the lakes 12 months ago. Here’s a little-recognized fact: Trillions of gallons routinely come into and leave the lake systems through uncontrollable natural events. Last spring’s heavy rains swelled those two lakes by roughly 10 trillion gallons — give or take a trillion or two — in only one month.

These figures should be kept in mind when someone proposes prohibiting water withdrawals. An ironclad interstate compact being developed under the Great Lakes Charter would trigger a multistate regulatory response if 1 million gallons per day were to be diverted from the Great Lakes Basin. If this withdrawal sounds enormous, it helps to remember that along Michigan’s rivers you can watch a million gallons go by in only the time it takes to eat a sandwich — or in some cases just chew and swallow one bite.

Or consider the rejection of a 1999 proposal in Ontario to ship Lake Superior water overseas by tankers. The numbers involved sounded large, but the permitted annual volume amounted to less than one-three-hundredths of an inch from the lake — a tiny amount compared to the annual fluctuations in lake levels, as noted above.

Similarly, some suburbs of Milwaukee are asking to tap into nearby Lake Michigan. A proposed annual usage rate would equal less than one-one-hundredth of an inch of the waters of Lakes Michigan and Huron. While the small size of the difference isn't decisive in the debate, it does remind us that Milwaukee’s suburbs are not actually trying to drain the Great Lakes.

Human impacts on water supplies are often surprisingly negligible against the monumental scale of natural hydrology, especially in Michigan, the Great Lakes State. In this context, even "big" numbers are often very, very small. Citizens shouldn’t let the simple mention of "millions of gallons" of water justify new water-use regulations that would purportedly prevent shortages that haven’t occurred under our current system.


Daniel Hager is an adjunct scholar with the Mackinac Center for Public Policy, a research and educational institute headquartered in Midland, Mich. Permission to reprint in whole or in part is hereby granted, provided that the author and the Center are properly cited.

[1] Feb. 6, 2005.

[2] Feb. 8, 2005.

[3] Feb. 8, 2005