Washington ? The U.S. Army Corps of Engineers would keep more water in upper Missouri River reservoirs during extreme drought under a plan proposed Monday.

The corps, which manages dams and reservoirs along the 2,341-mile river, does not plan to make seasonal changes to the river’s depth — the spring rises and summer lows that conservationists contend are needed to protect endangered fish and bird species.

But it does intend to acquire shallow habitat for pallid sturgeon to spawn and build or modify sandbars needed for terns and plovers to nest, according to the biological assessment it released Monday.

“There is little to no spawning of pallid sturgeon, and one of the things that we think is missing is the lack of habitat, spawning habitat,” corps spokesman Paul Johnston said.

Conservationists said those measures would not be enough to protect the species, pointing out they contradict a 2000 U.S. Fish and Wildlife Service recommendation for the flow changes.

“You can’t just do habitat,” said Chad Smith, Nebraska field director for the environmental group American Rivers. “You have to do flows and habitat.”

While he welcomed some of the drought measures, Senate Democratic Leader Tom Daschle said the plan was not the broader reform the river needs.

Daschle, D-S.D., said the corps “has once again proven its commitment to maintaining the status quo on the river by proposing a flawed management plan.”

Brig. Gen. William T. Grisoli, who oversees Missouri River management for the corps, said the plan was “the best balance” between helping species rebound and other river uses.

The corps sent the assessment to the U.S. Fish and Wildlife Service for review.

If the Fish and Wildlife Service agrees the species are protected, the corps will write an environmental impact statement and a new “master manual” — the long-term operating plan for dams that has been subject to a decade of dispute between conservationists and commercial barge operators and upstream and downstream states.

Montana and the Dakotas want steady or rising water levels in the river’s six huge reservoirs during spring to protect the eggs laid in shallow water by walleyes and baitfish. Those fish populations are crucial to multimillion dollar sport-fishing industries on the lakes.

Downstream states want enough water released from those reservoirs to keep barges moving below Sioux City, Iowa, and to provide water for cities, power plants and other uses.

Sen. Kent Conrad, D-N.D., said the proposal favored downstream interests too much, noting recreation in the Dakotas and Montana adds much more to those economies than the barge industry does downstream.

“There’s no balance,” Conrad said “It’s laughable if it weren’t so serious, and what’s serious here is people losing their livelihoods, a community wondering if they’re going to be without water this winter,” Conrad said.

Conservation groups were angered earlier this month when a new team was appointed to conduct the Fish and Wildlife Service review, replacing scientists who had worked on Missouri River issues for years.

Daschle and Conrad have asked the Interior Department’s inspector general to investigate that decision, a request they made along with Democratic Sens. Tim Johnson of South Dakota, Byron Dorgan of North Dakota, Max Baucus of Montana and Rep. Earl Pomeroy, D-N.D.