The U.S. Army Corps of Engineers made a decision today of historic importance. If projected water flows continue, the Corps of Engineers may open the Morganza Floodway, located in Pointe Coupee, LA, as a result of rising river stages and flow rates. The trigger to operate the floodway is when river flows reach a level of 1.5 million cubic feet per second at Red River Landing and are projected to continue rising. The amount of water to be released through the floodway alone will be three to ten times the amount of water that goes over the Niagara Falls, depending on which source is right. It will be an awesome (as in Biblical, not as in wonderful) spectacle. The resulting flood will inundate and kill most of the wildlife in 3 million acres of land. The flooding will also disrupt oil and gas production in the rich Louisiana oil and gas fields. One source notes that even if the Morganza Floodway is not opened up, the Mississippi will overtop the levee anyway and water will still flood the Atchafalaya basin. If the floodwaters are not allowed to flow into the Atchafalaya basin then some worry that New Orleans could be inundated.
This flood is a rare example of the difficult decisions that go into flood control design and planning. It is also an example of why levees are both part of the solution and part of the problem. As levees rise and channels narrow, the water level in the river also rises. While this saves many towns and farms that rely on the levees for protection, it can also increase the amount of devastation that occurs when floodwaters exceed the carrying capacity of the channel.