I had always heard that levees can cause floods in addition to containing them, but I never was quite sure how. I thought that it was because the levees contained the floodwaters and made them run even faster and deeper so that if the levee failed then the flood would be worse than if there had been no levee at all. And maybe that is right.
But last weekend we had a different kind of levee-caused flood in Dallas. This one was caused when the large volume of rain that fell in a short period of time couldn’t be drained off fast enough. The storm sewers flow into the Trinity River, which is surrounded by levees on its path through the white part of town. The storm sewers have to be pumped over the levee to get into the river and the water came too fast for the pumps to keep up, backing the runoff up all over Dallas.
In Here Comes the Flood the Observer’s Jim Schutze uses the incident to rip into the proposed Trinity River Project again, arguing that if the levees are raised and paved instead of upgrading the pumping system then this sort of thing will be all the more common in the future. Meanwhile over at Dallasblog, Trey Garrison’s Gonna Take More Rain Than That checks in with supporters of the Trinity River Project who point out that the levees did a good job of keeping the river contained between the levees and out of downtown.