Washington ? The Missouri River can operate without changes sought by environmentalists to save endangered fish and birds, a federal judge ruled Monday.

U.S. District Judge Paul Magnuson ruled in favor of the Army Corps of Engineers on Monday on all counts. His 51-page order came nearly a year after a different federal judge ordered the changes and, when corps leaders refused to act, cited them for contempt.

Magnuson, a St. Paul, Minn., judge, blocked the contempt citation last year after taking over the river litigation.

Conservation groups will weigh whether to appeal.

“Americans deserve more than ecological decline, economic stagnation, and political stalemate along the Missouri River,” said Rebecca Wodder, president of the lead group, American Rivers. “We will not give up the fight to save this river for future generations.”

Environmentalists have denounced the corps for giving preference to barge shipping downriver over creating an ebb and flow to protect wildlife.

It is a 14-year battle between conservationists, who along with the fishing and recreation industry in Montana and the Dakotas want more ebb-and-flow, and downstream farming and shipping interests, who argue spring rises and low summer flows would halt barge shipping and cause flooding.

The corps said the ruling shows the agency has balanced all the demands on Missouri River water. The 2,341-mile river flows from Montana through the Dakotas, Nebraska, Iowa, Kansas and Missouri to St. Louis, where it empties into the Mississippi River.

“That’s been our goal forever, is to look at all the authorized purposes, plus the Endangered Species Act, and see if we can’t make sure that we serve all of these purposes,” said Paul Johnston, spokesman for the corps in Omaha, Neb., where Missouri operations are overseen.

“The number of lawsuits points out it’s a pretty narrow line, and apparently we’ve managed to stick to it for the time being,” Johnston said.

A spokesman for the Justice Department, which is defending the corps, applauded the ruling.

“The court overwhelming recognized the difficult decision that federal agencies have to ensure navigation, protect recreation and safeguard wildlife,” said the spokesman, Blain Rethmeier.

The corps this year updated river operations that had essentially gone unchanged for more than 40 years. The pallid sturgeon and two shorebirds, the interior least tern and piping plover, were placed on the endangered and threatened species lists decades after the old plan took effect.

The U.S. Fish and Wildlife Service ordered the corps more than three years ago to elevate flows in the spring and reduce summer water levels to protect habitat.

But under the Bush administration, service biologists backed off, saying in December that summer water levels can be kept high enough for barge shipping if the corps also builds new habitat for the sturgeon.

The service said that instead of creating a more seasonal ebb and flow to sustain fish and birds, the corps can comply with the Endangered Species act by building 1,200 backwater acres of pallid sturgeon habitat by July 1.