The sleeping bear’s eyes may have begun to open. Perhaps the Corps of Engineers is signaling that it will begin acknowledging that the management of the entirety of the Mississippi River is connected to the health of the coastal wetlands in Louisiana. In a front page story on Sunday July 5, 2009 in the Baton Rouge Advocate Richard Burgess writes an article entitled, Corps considers change in water flow into Atchafalaya.
Nancy Powell, chief of the Corps’ New Orleans district hydraulics and hydrologic branch, suggests that the Corps might operate the Old River Control Structure at the northern end of the Atchafalaya River in the interest of Louisiana coastal restoration and preservation. It seems like an obvious thing to do, but the reality and symbolism of the Corps making this philosophical shift in policy would be profound.
At a time when the Corps was just beginning to manage the Mississippi River for the purpose of navigation, the Red River was a tributary entering the Mississippi River at the northern side of what was called Turnbull Bend. In turn, the Atchafalaya River was a distributary exiting the main channel of the Mississippi River at the southern side of Turnbull Bend. In 1831, Captain Henry M. Shreve, an early agent of the Corps, dug a canal through the neck of Turnbull bend. This canal called “Shreve’s Cut” changed the flow of the river in a profound way.
Shreve’s Cut made it more likely the Mississippi River’s main channel would change course and adopt the course of the Atchafalaya River’s channel as the Mississippi River’s main channel. In the 1950’s, the Corps built the Old River Control Structure in an attempt to rectify its earlier misstep digging Shreve’s Cut and to prevent the eventuality of the Mississippi River changing course from happening. The structure has since then been used primarily for this purpose. And undoubtedly an important purpose it is. The economic damage that would be caused by the Mississippi River’s main channel changing courses to adopt the Atchafalaya River’s channel as the Mississippi River’s own main channel would be extraordinary.
The America’s Wetlands web site has a good description of the Old River Control Structure and the history of Turnbull Bend along with some useful diagrams. The section of the web site is called Controlling the River.
The operation of the Old River Control Structure at Simmesport is the very essence of management of the Mississippi River. The Corps has not historically even considered managing the river north of the Louisiana coastal zone with consideration of the impact of those actions on the coast of Louisiana. The Corps has, heretofore, managed the Mississippi River north of the Louisiana coastal zone as though the Mississippi River to the North of the coastal zone was not casually connected to coastal land loss in Louisiana.
By acknowledging the connection of the Old River Control Structure to coastal restoration and preservation, the Corps might manage the distribution of sediment load of the Mississippi and Red Rivers in a more strategic way to aid with coastal restoration and preservation projects. The gates or “dam” at the Old River Control Structure were built to allow for the passage of sediment in the river through the gates. This allows sediment to flow into the Atchafalaya River or remain in the Mississippi River at the Corps’ choice. This design is different from other large earthen dams in the Mississippi River drainage basin that trap virtually all the sediment that enters the reservoir behind the dam. This, of course, suggests that dams could be built that do not trap sediment in the reservoir behind them, but that is another story entirely.
The idea that the Corps could operate the Old River Control Structure to help with coastal restoration and preservation in Louisiana is a small gesture. The Corps has not even yet decided what to do. Nevertheless, the acknowledgment of the connection is symbolically significant. I have to agree with the Corps’ Ms. Powell as quoted in the Baton Rouge Advocate article, “It’s kind of exciting.”