Canada's stores of fresh water are not as plentiful as once thought, and threaten to pinch the economy and pit provinces against each other, a federal document says.

'We can no longer take our extensive water supplies for granted.'— Environment Canada report

An internal report drafted last December by Environment Canada warns that climate change and a growing population will further drain resources.

"We can no longer take our extensive water supplies for granted," says the report, titled A Federal Perspective on Water Quantity Issues.

The Canadian Press obtained the 21-page draft report under the Access to Information Act.

It suggests the federal government take a more hands-on role in managing the country's water, which is now largely done by the provinces. Ottawa still manages most of the fresh water in the North through water boards.

The Conservatives promised a national water strategy in last fall's throne speech but have been criticized since for announcing only piecemeal projects.

The Tories, like the previous Liberal government, are also behind in publishing annual reports required by law that show how water supplies are used and maintained.

The last assessment posted on Environment Canada's website is from 2005-06.

The internal draft report says the government currently does not know enough about the country's water to properly manage it.

"Canada lacks sound information at a national scale on the major uses and user[s] of water," it says.

"National forecasting of water availability has never been done because traditionally our use of the resource was thought to be unlimited."

Canada has a fifth of the world's supply of fresh water, but only seven per cent of it is renewable. The rest comes from ice-age glaciers and underground aquifers.

One per cent of Canada's total water supply is renewed each year by precipitation, the report says.

Moreover, government data on the country's groundwater reserves is deemed "sparse and often inadequate."

That's in contrast to the United States, which has spent more than a decade mapping its underground water reserves. Canada shares aquifers with the U.S., and the report says: "Our lack of data places Canada at strategic disadvantage for bilateral negotiations with the U.S."

Through an e-mail from his spokesman, Environment Minister John Baird said he welcomed the report's findings.

"This report is a one-stop shop document that can guide us toward ensuring that we get clean, safe water to Canadians, wherever they choose to live."

The report forecasts droughts in the Prairies and groundwater shortages in British Columbia and the Great Lakes-St. Lawrence River basin.

There are already signs of water shortages in the Great Lakes. Lake Superior, the largest of the five, fell to its lowest level on record last September. Lakes Michigan and Huron were about 50 centimetres below their historical average levels last fall.

The report says a 0.08- to 1.18-metre drop in Great Lakes water levels costs the hydro-electric industry between $240 million and $350 million each year.

The report also warns of a "heightened risk" of showdowns between the provinces, and between Canada and the States, if the water supply dips too low.

Canada insists its water is not for sale. But a parched southern neighbour could ratchet up pressure to ship water south if its supply continues to dwindle.

Suburban sprawl in the southern United States and agricultural water usage have spawned a water crisis that threatens to worsen in the future.

Atlanta's main water source, Lake Lanier, shrank to an all-time low last November. Lakes fed by the mighty Colorado River, which supplies water to more than 20 million Americans, were just half full last year. Los Angeles had its driest year on record.

The Environment Canada report is one in a string of grim federal studies on climate change.

Natural Resources Canada released a major study this spring predicting more frequent droughts, severe floods and wildfires, and declining water quality and quantity.

Last month, Health Canada released a 500-page report warning of heightened health problems as the climate changes, ranging from more heat-related illnesses and deaths to outbreaks of previously unknown infectious diseases.

Those reports were released late in the day, with little fanfare.

Tony Maas, a senior policy adviser at WWF Canada, a Toronto-based conservation group, said he's pleased the government is studying the impacts of water shortages.

"The fact that they're even taking this close a look at this issue is good news in my mind, because they've been away from the fresh-water scene for so long," he said.

Liberal MP Francis Scarpaleggia, the party's water critic, says Ottawa needs a junior water minister to focus attention on the issue.