Missouri river at risk of drying to mere trickle

The longest river in America has been so badly affected by drought it could be unnavigable by next year
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The Independent US

Two hundred years after its source was discovered, the giant Missouri river is drying up. The longest river in the United States, long nicknamed the Big Muddy, is becoming the Big Empty.

Two hundred years after its source was discovered, the giant Missouri river is drying up. The longest river in the United States, long nicknamed the Big Muddy, is becoming the Big Empty.

Six consecutive years of drought have cut its flow by a third, crippling agriculture, denuding reservoirs and endangering shipping. By next year the giant river - described by the author Mark Twain as "too thick to drink and too thin to plough" - is expected to become unnavigable. And scientists fear that this may be only the start, as global warming takes hold of the American West, causing droughts that could last decades.

When Meriwether Lewis and William Clark struggled up the river's 2,540-mile length to reach its source, in the Rocky Mountains in Montana in 1805, they were awed by its power. Lewis wrote - with better observation than spelling - that the three tributaries that meet to form the Missouri "all run with great valocity and thow out large bodies of water".

Not now. Thirty-nine of Montana's 52 rivers arelisted as "very dry" because of the drought. The governor of Montana, Brian Schweitzer, has said that this year is expected to be even more arid than the past six years. More than 60 miles of the giant Oahe reservoir on the Missouri, 231 miles long, have dried up, with just a narrow channel where there was once a lake that was up to five miles wide. Boat ramps, meanwhile, have been left stranded a mile or so from the nearest water.

Hydroelectric power from the dams on the river has been cut by a third, and riverside coal and nuclear plants are running out of cooling water, threatening power cuts and blackouts. Farmers are having to do without water to irrigate their crops. Shipping is also beginning to shrink. The largest barge operator has not run a vessel up the river for two years because the water level is so low, and though some traffic continues, officials say it will probably have to cease altogether next year if the drought does not break.

The situation has become so grave that Governor Schweitzer has asked the Pentagon to bring home some of the state's 1,500 National Guard troops from Iraq so that they will be ready to fight fires in Montana's tinder-dry forests.

But the most serious threat to the Missouri, however, is the lack of snow in the Rockies. The "snowpack" on the mountain range provides 70 per cent of the river's flow, releasing water gradually as it melts in the spring and summer. But in some places it is between a half and a quarter of its usual size; in January golfers were playing in shirtsleeves on Montana courses that are normally covered by snow until April.

Global warming is being blamed for the lack of snow, and may bring even harsher conditions in future. Studies of tree-rings in the area, stretching back 1,200 years, show that in previous warm periods, the area was hit by mega-droughts lasting 20 or 30 years at a time.

Governor Schweitzer warns that this drought is "probably going to be around for a little while". Experts increasingly fear that the Missouri - and much of the American West - may be reverting to its historic dryness, with incalculable consequences for scores of millions of the region's inhabitants.

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