Major development along the Mississippi since the last big flood in 1993 may have exacerbated the current crisis, the Wall Street Journal reports. Nearly 30,000 homes have been built around St. Louis on land that was underwater then, forcing the river into a channel half the size it was 100 years ago, making it run higher and faster. With the river expected to crest this weekend, debate has intensified over how much of the problem is man-made, the Wall Street Journal reports.
Bigger, stronger levees have made more wetlands viable for development, but that adds additional runoff to the flow, in turn increasing demand for taller levees, scientists and environmentalists say. "We're making these flood levels higher," one professor notes. "A stage of 38 feet was almost unheard of 100 years ago. Now it happens all the time."