Washington ? Missouri Gov. Matt Blunt said Monday the Army Corps of Engineers should abandon plans for a spring rise on the Missouri River next year or face legal action from the state.

“This plan could devastate farm families’ crops and would further undermine environmentally friendly navigation,” Blunt said in a letter to the corps.

After more than a decade of legal disputes, the corps in October announced plans for two “spring pulses,” or releases of water from upstream reservoirs to encourage spawning by an endangered fish, the pallid sturgeon.

Environmental groups seeking to protect river wildlife support the move. Blunt and other Missouri officials have long opposed the idea, fearing it could flood thousands of acres of farmland in that state.

In his Dec. 16 letter, Blunt argued there is not enough scientific evidence to show a spring pulse will even help the pallid sturgeon. He said the plan is contrary to the corps’ primary mission of flood control and navigation.

Since the corps made its proposal, it has received hundreds of comments at public meetings and in writing, said Paul Johnston, a spokesman for the corps’ northwestern division office in Omaha, Neb.

“The courts are always an option, but we think we’re on pretty firm legal ground here,” Johnston said.

A final operating plan is expected sometime in early January, but Johnston said the agency remains committed to the spring pulses as long as there is at least 36.5 million acre-feet of water in upstream reservoirs.

“Our goal is to give people as much notice as we can so they can make their business decisions,” Johnston said.

Blunt’s letter also complains that the spring rise would limit upstream water available later in the fall, in the event of a drought. Low river levels have made shipping more unpredictable for barge companies, and this year the corps cut the navigation season to 48 days – the shortest season on record.

That is not likely to change much next year. Johnston said the corps is looking at another shortened navigation season of about 50 to 58 days.

“Folks already know that we are anticipating minimum navigation flows all year,” Johnston said.

The corps developed its spring rise plan in response to a 2003 opinion from the U.S. Fish and Wildlife Service, which long had pushed for changes to help the pallid sturgeon. Since then, the corps has spent months meeting with farmers, navigation interests, environmental groups and state representatives to balance competing interests along the nation’s longest river.

A federal appeals court ruling earlier this year largely upheld the right of the corps to manage the river.

A total of about 430 people came to a series of eight meetings in November in Kansas City, Mo.; St. Louis; Jefferson City, Mo.; Omaha, Neb.; Nebraska City, Neb.; Pierre, S.D.; Bismarck, N.D.; and Glasgow, Mont. The corps has received about 870 written comments, which are under review, Johnston said.