After four years of talks, negotiators have reached a deal aimed at preventing outsiders from raiding Great Lakes water and encouraging more efficient use of the coveted resource within the region.

“There were many difficult issues that required compromise, but a consensus has been reached,” said David Naftzger, executive director of the Council of Great Lakes Governors.

The agreement was motivated largely by fears that southwest states will try tapping into the lakes, which hold 90 percent of the nation's fresh surface water, as their populations and political clout grow.

Governors and premiers of the eight states and two Canadian provinces adjoining the lakes agreed in 2001 to develop a legal framework for keeping their waters inside the drainage basin. Staffers have been working on details ever since.

The final version has been submitted to the governors and premiers, who are expected to sign it during a meeting Dec. 13 in Milwaukee. State legislatures and Congress will be asked to approve a binding compact carrying out the accord.

Because the states cannot make treaties with foreign governments, they signed a separate, nonbinding agreement with the provinces.

The Associated Press obtained a copy of the agreement, which would outlaw most new or increased diversions of water - including groundwater, inland lakes and rivers as well as the Great Lakes - from the basin.

Exceptions could be made for communities and counties straddling the basin's boundary if they cannot meet their needs from other sources or through conservation. Such diversions could be only for public water supplies, and excess water would have to be returned to the basin.