Bulk-water exports.

Measured by surface area (82, l00 [km.sup.2]), Lake Superior is the biggest freshwater lake in the world. (Lake Baikal in Russia is much deeper and, therefore, has a greater volume of water.)

The lake contains 11,400 cubic kilometres of water; that's enough to fill all the other Great Lakes plus three extra Lake Eries. If you want it in litres the number is 11,400,000,000,000,000; that's 10 percent of the world's fresh surface water.

Lake Superior contains enough water to submerge all of North and South America to a depth of about a third of a metre.

That's enough "Wow" numbers to get the attention of people living in the parched U.S. southwest. Arizona and neighbouring states are growing rapidly; people want to move there because of the warm climate. But, this region of the United States gets very little rain and has almost no water resources of its own.

It gets worse. The region has suffered through five years of drought. Lake Mead, the body of water behind the Hoover Dam that makes generating electricity possible has lost half its water. Lake Powell in Utah, which powers the Glen Canyon hydro plant, has lost 60 percent. If the drought continues, these two massive electricity generators would shut down. And, the drought could last a while longer. Archeologists say there was a drought in the 13th century that lasted 23 years that forced the Anasazi Indians to move elsewhere.

So, a big, fat pipeline low ered into the Great Lakes looks like a tempting proposition. But, the Great Lakes system is not all inexhaustible supply source. Adele Hurley of the Munk Centre for International Studies says we don't know enough about this valuable resource. "No one has a good handle on how much of our water capital the region is now spending," she wrote in a 2004 Globe and Mail article. "The U.S. Geological Survey freely admits good data on evaporation, rainfall.., and groundwater don't exist."

It is known that the Great Lakes only receive about one percent of their entire volume in new water each year. So, withdrawing anything more than one percent of the volume would cause lake levels to fall.

In 1998, the Conservative government of Mike Harris in Ontario gave permission to a company to export water from Lake Superior. The Nova Group planned to fill tankers with fresh lake water and take it for sale in Asia. The company wanted to move 600 million litres a year.

When news of the permit broke there was an enormous fuss. There was such a huge public outcry on both sides of the border that the Harris government was forced to cancel the permit. Another consequence was the start of talks to find a way of preventing this sort of thing from happening in the future.

During 2004, two provinces and eight states bordering on the Great Lakes settled on an agreement to stop the export of large quantities of water. Or, at least that's what the Great Lakes Annex looks like on the surface. The Council of Canadians claims the Annex does precisely the opposite.

The Council hired Ottawa lawyer Steven Shrybman to take a close look at the proposed agreement. He gave his view that it would make it easier to divert "Great Lakes water to an extent that would threaten the ecological integrity of the Great Lakes and seriously challenge Canada's sovereignty with respect to these waters."

The management of Great Lakes water is covered by the Boundary Waters Treaty of 1909. The Treaty deals with the more than 300 lakes and rivers that straddle the border between Canada and the U.S., and control of these waters is a federal responsibility. The International Joint Commission (IJC) was set up by the Treaty. Its purpose is "to help prevent and resolve disputes relating to the use and quality of boundary waters and to advise Canada and the United States on related questions."

Critics say the Great Lakes Annex would take water diversion approvals out side the Boundary Waters Treaty and out of the control of the IJC.

Ottawa says it has safeguards in place to prevent the bulk export of fresh water from the Great Lakes and elsewhere.

Many environmental groups have a different view. They say the wording of the draft agreement would allow diversion of water to rapidly growing cities in Great Lakes border states that are outside the lakes' drainage basin. This could cause a major problem.

Water now is taken out of the lakes for such uses as irrigation, drinking, or cooling a nuclear reactor. After use within the Great Lakes Basin, that water eventually finds its way back to the lakes. But, take it out of the basin for use elsewhere and it doesn't dram back into the Great Lakes; it's lost into someone else's drainage basin.

Another problem is that the Annex allows for "small diversions." The environmentalists fear that a lot of small diversions can quickly add up to a big diversion.

What is clear is that not much is clear--yet. Globe and Mail columnist Murray Campbell calls the Great Lakes Annex "unspeakably dense." "Very, very complex" and "Highly complicated" are descriptions offered by others.

At the time of writing, the Ontario Liberal government of Dalton McGuinty had pulled out of the draft agreement. Natural Resources Minister David Ramsay said the safeguards against bulk water diversions were not strong enough for his liking.

The scientists, bureaucrats, politicians, and lawyers are back at the negotiating table. As Sarah Miller of the Canadian Environ mental Law Association says: "With some tweaking, this [the Annex] could get us on the right path."

However, in the long-term, this agreement may prove to be of little value. Climate change may have a profound effect on the amount of water in the Great Lakes. Already, lake water levels have been lower over the last decade than for a long time. Cottage docks haven't reached the shoreline in many areas for a number of years. Opinion is divided about whether this is a normal fluctuation or the result of higher evaporation because of a series of very hot summers caused by global warming.

However, the Great Lakes may not suffer as severe a negative impact as other parts of North America due to climate change. But, there could well be in creased demand to transport Great Lakes water to parched areas of the continent.

In addition, major migration into the Basin could occur; people will likely move from water-starved regions to where there is abundant fresh water, just as the Anasazi Indians did eight centuries ago. There would be a lot of negative impacts on the environment from a suddenly increased population.

FIRE AND ICE

Lake Superior was created by forces of Nature beyond imagining. First came a massive eruption of lava that began about one billion years ago and lasted for 22 million years. This put down a layer of basalt rock about 16 kilometres thick. Erosion and geological forces created a shallow basin.

About two million years ago, the ice arrived. As the glaciers expanded across the landscape they gouged out the Great Lakes. Ten thousand years ago, the ice retreated and the lakes filled with meltwater,

THE NON-TIDAL TIDE

The gravitational pull of the Sun and Moon is not strong enough to produce a noticeable tidal rise and fall in any of the Great Lakes. However, certain weather conditions can produce water movement that looks a tot like a tide. A strong and steady wind blowing across the length of a lake causes water to "pile up" on the downwind shore. This effect is called a seiche (pronounced saysh). When the wind stops blowing, the water sloshes back and forth from one shore to the other, like water in a bowl that's been tipped then laid flat. The rise of the water lessens with each lake crossing, but can staff out at above one metre in height. In Lake Superior, the period of a seiche (the time it takes for water to slosh between the two farthest coasts) is about eight hours.

FACT FILE

One out of every three Canadians and one out of every ten U.S, residents depend on the Great Lakes for their water.

FACT FILE

During storms on Lake Superior waves can reach 10 metres in height.

FACT FILE

Thirty-five percent of Lake Superior's surface area is in Canada.

Websites

Council of Canadians--http :// www.canadians.org/

Canadian Environmental Law Association (Great Lakes Annex)--http://www.cela.ca/ coreprograms/ detail.shtml?x=1906

International Joint Commission--http:// www.ijc.org/

Lake Superior Alliance--http :// www.superioralliance.or