Rising waters and rising fears: researchers express concern about the future of the Mississippi River and delta area.
School of Renewable Natural Resources Professor of Hydrology Yi Jun Xu and his team have found that the Mississippi River’s bed is rising downstream of Old River Control Structure, a floodgate system in central Louisiana. It has created a pinch point that could fill with mud during a flood, which would force the water into the Atchafalaya River once more.
Right now, according to Xu, about 75 percent of the water from the Mississippi River continues to flow into the Mississippi, and 25 percent goes into the Atchafalaya River. This process is controlled by the federal government; Louisiana cannot change these percentages.
Xu and his team’s work on the Mississippi-Atchafalaya River is multi-faceted. It includes physical hydrology, sediment transport, and fluvial geomorphology, as well as river water quality, biogeochemistry, and nutrient/carbon transport.
Xu emphasized the importance of the Mississippi River in Louisiana’s culture and economy.
“[The river systems are] important to Louisiana because the state is largely shaped by the River historically and currently,” Xu said. “About half of the state’s population is living in the Mississippi River Delta, makes a big contribution to the economy. At the mouth of the Mississippi, we have one of the most productive fisheries in the world.”
Louisiana contributes nearly 25 percent of the total fishery product in the United States and No. 2 in the world behind Alaska, according to Xu.
“It is too important to ignore,” Xu said, commenting on the river.
Since 1963, the Old River Control Structure has solved two main issues caused by the Mississippi River: flood control and navigation. This leaves one issue unanswered — sediment transport.
According to Xu, sediment load has been declining in the last century. Xu said the river gives less than half of the amount of sediment as it did 100 years ago. If the river doesn’t carry sediment, the Mississippi Delta will disappear.
Sediment erosion has been a major cause of coastal land loss in Louisiana over the years.
“I think it is very important for the public to understand that we right now are in a situation in South Louisiana to think more about adaptation instead of restoration,” Xu said. “Restoration has not been clearly defined. Restore to when? The whole environment has changed, climate has changed, sediment has changed.”
Xu was recently awarded a National Science Foundation Rapid grant. The grant will allow Xu to investigate carbon dioxide emission from the River during a recent flood.
The Journal of Hydrology will soon publish one of Xu’s team’s research papers on carbon transport and carbon dioxide emission.
