River Otter

It was time this week for some science and a little something on tap, time for another episode of Washington University’s Science on Tap series. The night’s featured speaker was Dr. Robert Criss, a professor of earth and planetary science. His talk was entitled, “Another 200 Year Flood? What Missouri Can Do to Stop Repeat Flooding” Criss started in Saint Louis as an isotope scientist, studying hydrogen and oxygen isotopes. So, what common molecule does hydrogen and oxygen make? Then along came the 1993 flood and he was swept away. This talk was pretty political and pointedly anti US Army’s Corps of Engineers. It was also very Saint Louis centric, almost as if we are the nation’s sinkhole. I sat across the table from Anne and I observed many conflicted expressions across her face during the course of the Criss talk. She worked many long years with the Corps and to hear the people that she worked with denigrated so, pained her. I could see that, but Criss had his points.

He had two charts that I thought were pretty telling. The first one featured a hydrological map of Missouri and its surrounding region. All the rivers that had hit their highest flood stage ever, in 1993, were colored blue, which was pretty much all of them, because the ’93 flood was billed as a 200 year flood. Overlaid on them were stretches of river that had flooded since ’93 and whose subsequent flood stage had exceeded the 1993 levels. Eyeballing his map, it seemed to me that at least a good third of all river miles had flooded higher than the great flood of ’93. His second chart was a history of flooding on the Mississippi in front of Saint Louis, in histogram form. It showed the height of each flood’s flood stage from the Civil War to the present. From then until now the moving average height of those bars rose.

He had identified a systematic problem, but what were its causes? The Corps has sculpted the big rivers for barge traffic. They have been optimized to facilitate the movement of barges. A tow on the Mississippi is longer than an aircraft carrier, longer than a supertanker. One suggestion was to reduce the size of these tows, which would relax the constraints for navigation and leave more room for other concerns to be addressed, like flooding. On both big and small rivers he also identified the larger culprit of development. In ’93 the Gumbo Flats were flooded by the Missouri River. The levee broke and everything behind it was lost. Since then, a new bigger levee has been built and a billion dollars in new development created behind it. It has been renamed Chesterfield Bottoms and is now a shopping Mecca. Another similar development on the flood plain is being pursued just downriver in Maryland Heights. Criss proposed that to solve flooding, these developments must be restricted by real enforcement of existing zoning laws regulating floodplain development. Until the Corps does this, the flooding will continue.