The pump project is situated in the Mississippi-Yazoo Delta, a 7,000-odd-mile lowland swath that extends in a long diamond from Memphis, Tenn., to Vicksburg, Miss. Since the 1800s, Americans have worked hard to become wealthy from the Delta's rich river-mud-turned-topsoil and its proximity to Mississippi River shipping traffic. Their efforts have been supported by the Army Corps, whose history and power is inextricably twined with over 150 years of complex, costly, and politically charged efforts to control flooding and aid commerce along the Mississippi.

The Yazoo hydraulic pump would be the world's largest, powerful enough to drain up to 6 million gallons of water a minute from over 300 miles of wetlands in northwestern Mississippi. Ostensibly a flood-control boon for poor Delta farming communities, in reality "more than four-fifths of the economic benefits calculated by the Corps would go to flood-prone farmers who already collect gigantic subsidies to grow soybeans on marginal land," as Mike Grunwald reported last week in Time. And thanks to legislative sleight of hand by Sens. Thad Cochran and Trent Lott (both R-Miss.) in the mid-1990s, the federal government would pick up the entire $220 million tab, with no cost-sharing by the state of Mississippi.

The Corps has estimated that around 67,000 acres of wetlands would be affected or degraded; scientists put it closer to 200,000 acres -- and over 500 of them signed a letter decrying the project (PDF). Tomato, to-mah-to -- either way, apparently EPA has decided the ecological costs are way too high, and per its responsibilities under the Clean Water Act, it's setting up to veto a Corps project for the first time since 1990. Says eco-advocate Melissa Samet, who works on Corps reform with the nonprofit American Rivers, "EPA is doing exactly what it ought to be doing in this case" based on the overwhelming facts. Samet says that the Fish and Wildlife Service has also submitted a hard-hitting critique of the pumps plan, estimating that it would significantly harm fish and wildlife in the affected areas.

The Yazoo Pumps project is "a relic of an era when wetlands were considered wastelands," writes Grunwald. It's an attitude that's all the more aggravating given our better grasp now of the (arguably) abstract value of wild habitats, plants and animals for their own sake, and the calculable economic benefits of wetlands in protecting humans from catastrophic floods and storms.

Even if the Yazoo Pumps project dies its much deserved death, the Army Corps is still a major player in the future of the Mississippi River Delta. The president's budget for Fiscal Year 2009 includes a request of $10.5 billion for the Corps -- including $5.76 billion targeted to flood control and storm protection projects for New Orleans.