Environmental groups accuse the administration of endangering existing and future wilderness areas by using the disclaimers to recognize road rights of way in Alaska and other Western states.

But the disclaimer process also can be used by states to claim navigable waters. So Alaska jumped at the opportunity, asking for the Black River disclaimer on Feb. 14, according to Michael Haskins, the BLM's land and realty branch chief in Anchorage.

Changes are not likely to be noticeable if the state wins its claim. The federal government hasn't disputed the state's ownership in the past.

There is no mining in the river, and a disclaimer won't affect the authority of federal and state fish and wildlife managers, according to Tina Cunning, a co-chair of a state agency working group on navigable waters.

Nevertheless, the state believes the Black River claim and others like it are "crucially important" to establish access rights for Alaska residents, said Cunning, who also serves as the Department of Fish and Game's state-federal program manager in Anchorage.

"We have these thousands and thousands of rivers and lakes in the state that we thought we got title to at statehood, but that we have had to go individually to court on," Cunning said.

The state has secured title to just 13 such waters since 1959, she said.

The Black, Kandik and Nation rivers were the subject of one such case in the 1990s. A state-federal working group under former Gov. Walter Hickel and the first Bush administration tried to resolve the disputes out of court.

The group selected the three rivers as test cases, out of a list of about 200 clearly navigable water bodies. The federal agencies dropped out during the Clinton administration. So the state sued.

It won on the Kandik and Nation rivers, which flow southwestward into the Yukon between Circle and Eagle.

But the federal government adopted a novel legal strategy on the Black River. It simply refused to say whether it had an interest.

Because of the peculiarities of federal law, the judge was not able to rule on who owned it, Cunning and Haskins said.