Archive for the ‘Mississippi River Flood’ Category

Thoughts on the Flood Control System for the Mississippi River

Wednesday, May 18th, 2011

Author: Phillip Doiron, Homeland Security Specialist, IEM

In this blog post, I wanted to express some thoughts on the flood that is presently moving south along the Mississippi River. I grew up in Vicksburg, Mississippi, where some of the worst flooding has been observed, and my father was a civil engineer for the U.S. Army Corps of Engineers (USACE) Vicksburg District. I retired from the USACE Research Center in Vicksburg.

Water flows through four open gates of the Morganza spillway into the Atchafalaya River basin in this May 15, 2011 photo. (The Lafayette Daily Advertiser/P.C. Piazza/AP Photo)

One thing that is very obvious when looking at the current situation is that the flood control system that was designed and built following the Great Flood of 1927 is working as intended. In addition to the levees that the USACE built, floodways and spillways were also constructed and have been integral to the successful operation of the flood control system.

The levees have been built along the Mississippi to protect as much rural area and as many cities as possible. The levees are not small structures. In some places, they measure 120 feet across at the base and 30 to 40 feet high. Once the USACE builds the levees, the maintenance of the levees is turned over to local levee boards. Most of these levee boards take this responsibility seriously and are very active in maintenance programs. However, when a flood occurs, there might be problem areas along the levee system. After each flood, problem areas are identified, and the USACE comes in to correct them. For example, the height of the levee may be raised following a flood. I know this occurred in several places after the 1973 flood. There will be remedial actions following this flood as well. (more…)

The Mississippi River Flood: How bad could it get?

Friday, May 13th, 2011

Author: Dr. Lloyd Blanchard, Director of Public Performance Management, IEM

By now, many Americans are aware of the major flooding of the Mississippi River. The river’s water level is reaching record heights not seen since the 1920s and 30s. How bad is it? This blog post tries to answer this question for the lay reader. In short, it’s very bad.

The news to date has been dominated by the flooding in Memphis, TN, where the nation’s largest river crested at nearly 48 feet on Tuesday, May 10. What does this mean? The level at which the river begins to flow over its bank, but not flood any buildings, is 28 feet. This is called the “action” stage by flood experts. The “flood” stage is the level above which life and property are threatened. At Memphis, the river’s flood stage is 34 feet. We are well beyond this. Damages will be severe. (more…)

Early Thoughts on the Mississippi River Flooding of 2011

Wednesday, May 11th, 2011

Author: Gary Scronce, Director of Preparedness Programs, IEM

Since 1986, I have lived in southern Louisiana just 2 miles from an Atchafalaya Basin Levee and crossed the mighty Mississippi River at least twice a day. Given this, it is only natural to consider the risk of flooding where my family and I live, particularly in the springtime. We all knew from watching the heavy snowfalls in the Midwest and upper Midwest during winter that the river was likely to rise this year. What we had not anticipated was all of the thunderstorm activity that swept across the same areas and especially through the Ohio River Valley this spring. We have watched what has happened to the north of us and now have an understanding of what is going to reach southern Louisiana thanks to the U.S. Army Corps of Engineers, the National Weather Service River Forecast Center for the Lower Mississippi, and our local news stations and newspapers.

For those not familiar with the lower Mississippi area and the flood control structures in place, one of the best graphic depictions I have seen is located here: (more…)