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SCIENCE FILE

River Gamblin'

An Army Corps of Engineers crew broke 70 years of tradition in managing Mississippi navigation, drawing down the water level to provide grassy stopovers for migrating birds. But it leaves less cushion for ships.

March 27, 1997|MARLA CONE | TIMES ENVIRONMENTAL WRITER

ALTON, Ill. — Watching grass grow wasn't always a priority at Locks and Dam No. 26.

The technicians here, staffing the controls of one of the world's mightiest rivers, are entrusted with keeping billions of dollars in cargo vital to the nation's economy navigating safely through St. Louis. But quietly, hoping not to draw attention to himself, David Busse broke 70 years of tradition to change the way the Mississippi is managed.

Quite literally, Busse and his crew at the Army Corps of Engineers are matching the pace at which grass grows, opening and closing the Mississippi's gates to manipulate its pools down to a fraction of an inch so that birds and other creatures can thrive there.

Navigation tradition dies hard in the corps, which has long struggled to control nature, not empower it. As champions of commerce and defenders of public safety, corps engineers build dams. They channelize streams. They stop floods, or at least try to. And in doing so, they have destroyed many of the wetlands and grasses that nourished North America's migratory birds.

But that mind-set is slowly changing, and it happened unceremoniously here, where the engineers simply took matters into their own hands one day about three years ago. With little more than the flip of a switch, Busse's team has created 3,000 acres of new grasslands along the Upper Mississippi, a stopover for hungry and tired migratory birds.

Every summer, the technicians draw down three deep pools that jut out along the river, keeping them low for 30 days. As the water retreats, seeds germinate and grass creeps toward the sun's rays. Then, the technicians raise the water at the painstakingly slow pace of an inch or so a day to keep the surface just below the tips of the new grasses.

The drawdown leaves the river with less of a cushion for ships, which means the corps gatekeepers must be extra vigilant. Almost 80,000 ships and barges pass through these locks yearly, carrying 78 million tons of corn, coal, crude oil and other goods.

"It requires a lot more checking of the hydraulic situation upstream because if we are wrong, we can lose navigation," Busse said. "We only have one project purpose--to maintain navigation--and we will not and cannot do anything to imperil that. So when we are operating on this fringe, we are taking on a lot of responsibility. But we think the benefit is well worth it. We are giving nature enough time to grow the grasses."

In an era when many environmental issues are polarized, when the usual refrain from the behemoth, slow-moving corps is "no way" or "let's study that," the change in river management shows conservation can be relatively simple and painless.

During the drawdown, a Missouri biologist heads out every week to measure how much the grasses, called smartweed, have grown. Then Busse or one of his staff continuously monitors the flow from upstream and calculates how much to manipulate the gates controlling the river to match the grasses' growth. A technician punches the data into a computer, opening the gates to lower the pools, closing them to raise the water level. Sometimes the instructions need to change every half-hour to keep up with the river's changing flow.

The lush, emerald green quilt provides an oasis for ducks, herons, terns, rails and other birds that need to rest and feed during their long journey along the flyway's course. Nationally, more than half of all wetlands and grasslands have vanished, and because of the loss of habitat, waterfowl populations plummeted in the 1970s and 1980s. They are now beginning to rebound because of conservation efforts and improved weather conditions in the United States and Canada.

The new grasses also help filter pollutants that flow down the Mississippi to the Gulf of Mexico.

"Three thousand acres is a substantial area of new habitat," said John Smith, a wildlife research supervisor at the Missouri Department of Conservation. "We've lost a lot and what we've tried to do is offset some of those losses."

Scott Faber of the environmental group American Rivers, a longtime critic of the corps' management of the Mississippi, complimented the St. Louis team for "some innovative things to create habitat that are consistent with the navigation purposes of the river." And Sean Kelly, a migratory bird specialist at the U.S. Fish and Wildlife Service, said the corps "seems a little more open to experimenting."

Environmentalists had long wanted the corps to draw the pools down, putting a virtual halt to navigation for the entire summer. The corps dismissed the requests as extreme.

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