About 40 percent of levees along the Mississippi River in the Army Corps of Engineers district north of St. Louis are built higher than their authorized heights, according to the agency’s own findings.Expect more frequent floods, more damaging winds, more violent tornadoes and hurricanes, and other dramatic weather events in the future. And expect communities that can to try to protect themselves, even as it hurts their neighbors. Things are going to be difficult in the future.
The Corps’ Rock Island District, which covers an area beginning about 60 miles upstream from St. Louis, reports that about 80 out of 202 miles of levee systems it surveyed are improperly high, based on data yet to be publicly released.
“Some of those were between 2 and 4 feet above their authorized elevation,” said Scott Whitney, the Corps’ Rock Island District flood risk manager and chief of project management. “The revelation is out there that levee districts throughout this region have taken, in some cases, some pretty extreme measures to protect themselves.”
That protection, he notes, has come “at the cost of others,” with the added levee height leaving other areas more vulnerable to redirected floodwater. Whitney said the district is still developing a hydraulic model to understand how far-reaching the levees’ combined impact on flooding has been, including whether the St. Louis area has been affected....
Complicating matters further, stronger flood protection is increasingly coveted, with an unusual number of major floods taking place in recent years — a symptom consistent with more erratic trends in precipitation predicted by climate change.
“We’re in an extremely wet period,” said Whitney, noting that several of the region’s top flooding events on record have occurred in the last decade. “We’ve had a number of those in the last several years. People think, ‘My God, I’ve had three 100-year flood events in the last five years.’”
Tuesday, May 2, 2017
Every Town For Itself In Climate Change Era
St. Louis Post-Dispatch: