This is the VOA Special English Environment Report.

　　Last month a judge ordered the United States Army Corps of Engineers to begin to lower water levels along the Missouri River. The federal judge threatened hundreds of thousands of dollars of fines each day the corps did not obey. Environmental groups want the water lowered by dams to protect some kinds of birds and fish.

　　But the army engineers, who operate the dams, say they must keep the water deep enough for shipping. A judge in Nebraska late last year ordered them to do that. The engineers say the ruling last month to lower the river or face huge fines conflicts with that order.

　　Last week, still another judge blocked the fines temporarily. That judge is to decide all the current legal actions concerning water levels on the Missouri River.

　　The Missouri is the longest river in the United States, at a little more than four-thousand-kilometers. It begins in Montana and flows through North and South Dakota, Nebraska and Kansas. It ends in Missouri, where the waters enter the Mississippi River.

　　For many years, the Army Corp of Engineers has operated major dams along the Missouri. Environmental groups want the engineers to change the way they operate the dams.

　　Two kinds of birds on the federal list of endangered species live on small islands of sand in the river. These sandbars are underwater during nesting season under the current rules for the dams. The corps established these guidelines in nineteen-seventy-nine. At that time, the birds and a species of fish also at issue were not yet on the endangered list.

　　Last year the National Research Council said the dam system has hurt the ecosystem. The council is a private group that advises Congress. Scientists called for some natural river flow to be re-established to help repair damage. But their report also called for a balance between environmental and economic goals.

　　Critics of lowered water levels include shipping companies and farmers. These critics say the first job of the Army Corps of Engineers is to support shipping on the Missouri. They say changes could lead to flooded crops and homes.

　　The army engineers have been working on a new water-control plan for fourteen years. They say the plan will be ready next year.

　　This VOA Special English Environment Report was written by Caty Weaver.