Morganza is slowing being opened. The projected crests downstream have been revised, but as the previous post illustrates, the projected crests still leave very high water from Baton Rouge to New Orleans. We can debate (and will) the Corps decision to delay opening Morganza in hopes it could protect the floodway. Now that the floodway is in use, there is no reason to keep the river levels so high. Morganza could be fully opened. This would reduce the down river levels and flush the flood waters out of the lower river faster, rather than letting high water persist well into June.
Every day the river is this high, the levees get soggier and weaker, and more water pass under the levees. When the river is very high, navigation is also slowed and is more difficult. This increases the shipping losses. It also increases the chance that a navigation accident will break a stressed levee. Over the weekend, a string of barges broke loose and two barges struck the old Highway 190 bridge in downtown Baton Rouge. Fortunately, the bridge does not appear to be damaged. But those barges could also have hit the levee, and since the water is so high, such a hit would have a higher chance of breaking through the levee and letting water into downtown. The longer the Corps leaves the downriver areas with high water levels, the greater the change of a catastrophic levee failure. The longer the Corps keeps the river in flood, the great the chance of more upstream rain piling into the existing flood, and the higher the risk of the river system still being loaded with an early season hurricane.