Posted Sunday, June 30, 2002; 8:31 a.m. EST
The steamship Arabia, hauling supplies for the booming West, was chugging up the Missouri River north of Kansas City, Mo. one late summer day in 1856 when it snagged a submerged tree trunk and began taking on water. Two days later, the tops of its giant smokestacks sank from sight.

The Arabia was forgotten until 1988, when a salvage crew located the wreck more than half a mile from the present banks of the Missouri and raised its cargo — including beaver hats and bottles of cognac. The Arabia is testimony to the cycle of flood and erosion that for centuries had regularly reshaped the Missouri's course, in this case leaving a ghost ship marooned 45 feet beneath a cornfield.

The Missouri's shifty personality was a constant problem for Lewis and Clark, who struggled against its powerful current and crumbling riverbanks, and for the millions who would inhabit its flood zone over the ensuing 100 years. To 19th century westward expansionists, the Missouri was something to be harnessed, its rambunctious energy put to work. It was. Seven dams erected between 1933 and 1966 now master the once wild river as it follows its twisting, seven-state course from its headwaters near the Rockies to its confluence with the Mississippi north of St. Louis.

The dams profoundly altered the character of the Missouri, evening out its ³pulse² — the naturally occurring spring rises and summer drops — and capturing much of the silt that gave the waterway its nickname Big Muddy. The dams gave protection to some 1.4 million acres of rich, river-hugging farmland, curtailed damaging floods and made it possible to hem in the shifting riverbanks with miles of concrete levees and retaining walls. For the 10 million inhabitants now living and working along its 2,341-mile path, the Missouri is a provider: a source of drinking water, electric power and irrigation, and a venue for shipping, sport fishing and other recreation. The multitasking Mo delivers a $2 billion economic payoff each year to its huge family of riverside dependents.

By other measures, however, a big price was paid in loss of habitat for the wildlife that thrived on the river's natural ebb and flow. The Missouri's hydraulic system has been so tamed that environmentalists call it America's most endangered river. They propose a radical policy shift that would use the dams to restore the river's traditional behavior, unleashing a surge of water southward in the spring and allowing the flow to dwindle in summer, as it did in the past. The plan has triggered a fiery debate, roughly pitting Northerners who benefit from the river's natural attractions against Southerners who benefit from the river's commercial properties, ranging from barge haulers to farmers. It's a debate not so much over science as over who loses. Any change in the water flow will have serious consequences for someone's livelihood.

The science is straightforward. Two years ago, the U.S. Fish and Wildlife Service issued a report called a "biological opinion," urging the Army Corps of Engineers, which regulates the water flow, to change the way it runs the dams, warning that maintaining a steady flow will threaten two species of endangered birds — the piping plover and the least tern — and a similarly threatened fish, the pallid sturgeon, a long, snouted behemoth that looks like a refugee from the Jurassic period. A higher spring flow would signal the sturgeon to spawn and provide it with more food; the piping plover would find hospitable nesting ground on sandbars carved out by the rushing current. A summer drawdown would create shallows for the young sturgeons to survive and protect plover nestlings from being washed away.

The Fish and Wildlife Service viewed these endangered species as a proxy for the river's health, an opinion reinforced by a National Academy of Sciences report that found that 51 of 67 native Missouri fish species were scarce or in decline in the river, and the once prolific cottonwood trees, from which Lewis and Clark carved their dugout canoes, were vanishing from the river basin.

The proposal has set off a water war between people who make money from fishing and boating in the Dakotas and farmers and commercial interests downstream in Iowa and Missouri. From the hills above the tiny town of Oregon, Mo., the 2,500 acres of B.J. Bailey's farmland stretch off into the distance like a vast green carpet snug against the river. Planted with corn and soybeans, the rich bottomland is wonderfully fertile. But Bailey, a fourth-generation farmer, knows well that the river can turn against him: two earthen levees run the length of his land, and one grain silo is inscribed with a paint slash marking the high-water mark, 10 feet up. Bailey fears any change in the status quo will put parts of his acreage under water at planting time. "It doesn't take a high river to get this ground," he says, pointing to a tennis court­size ditch that was scoured out when the river came up over its banks. "We're always at the mercy of Mother Nature here, but to have to fight a man-made flood too just isn't right."

Don Huffman, a barge operator based in St. Louis, Mo., has been running the river between Sioux City, Iowa, and St. Louis since 1962. "Without consistent flows there is no navigation. We'd have barges running aground," he says. Higher water means more income for shippers: each additional foot of draft on the river allows a barge to load 600 tons more of cargo. Although the barge industry has been dwindling for more than a decade, Huffman argues that bargemen like him force truckers and railroads to keep their prices competitive, so farmers benefit too. Says Huffman: "I know people worry about the loss of wetlands and addressing ecological issues, but when they talk about putting the river back the way it used to be — it's not a practical answer. There were terrible floods. This is a different time now."

Upstream in the Dakotas, where river-fed reservoirs have stimulated an $86 million annual tourist business, pleasure boaters and anglers favor using the dams to mimic the natural flow, which will result in less water being sent downstream in the summer. That means more water for their marinas and lakes. In Garrison, S.D., behind the vast reservoir created by the Garrison Dam, businesses see their sales rise and fall with the mean level of the reservoir, swinging from as much as $11 million last year down to about $7 million in 1991, when the corps sent water south to keep barges from running aground.

Any changes recommended by the corps will have to be approved by Congress, and surely a court fight will follow. But don't expect any action soon. In June, the corps, in a truly heroic act of bureaucratic avoidance, announced that it was delaying its decision indefinitely. Doing nothing amounts to a victory of sorts for downstream states, where Missouri Senator Kit Bond and Governor Bob Holden have lobbied intensely to halt any change. But it angered environmentalists and upstream politicians like South Dakota Senator Tom Daschle who called the corps' non-decision "extremely disappointing." The delay, of course, has more to do with politics than with finding the best way to save the piping plover. With a re-election fight two years away, George Bush is unlikely to push the corps into doing anything to antagonize voters in Missouri, a swing state which he won by a mere 70,000 votes in 2000. "There is a lot at stake with this decision, and if that takes extra time, then extra time should be taken," Bond told a reporter recently.

Which is fine, unless you're a piping plover.

With reporting by Steve Korris/St. Louis