Wax Lake Delta
In 1941 the U.S Army Corps of Engineers constructed Wax Lake Outlet, a 22km channel meant to alleviate the risk of flooding in Morgan City, LA. This channel allowed water to exit Six-Mile Lake, which is fed by the Atchafalay River, and flow out into the Gulf of Mexico. Prior to 1941, the water from the Atchafalaya River entered into the Gulf of Mexico through the Atchafayala Delta.
The construction of the new Wax Lake Outlet allowed for the release of water and sediment into the Atchafalaya Bay. As this fast-flowing water entered into the 2m deep bay, it slowed down and sediment settled out. This formed the subaqueous portion of the Wax Lake Delta. Over time, as more and more sediment was deposited, the delta began to prograde. After an extremely large river flood in 1973, land was first exposed above the surface of the water, forming the subaerial delta. Wax Lake Delta has been continuously growing in elevation and prograding outward since then.
The Atchafalaya River receives water from the Red River along with approximately 30% of the Mississippi River water, which is diverted at the Old River Control Struture. The water of the Atchafalaya River is further divided, with Wax Lake Delta receiving between 40-50% of the river water, for a total discharge of 900-8800 m^3/s. This water and sediment discharge allows for approximately 1.0 to 3.5 km^2 of land building each year.
Despite originating from a man-made outlet, Wax Lake Delta has undergone surprisingly little structural alteration compared to the Atchafalaya Delta to the east, which has been dredged to allow navigation along the main channel. This unique aspect of Wax Lake Delta has given us a great opportunity to study a prograding delta from the early stages. Due to the similarity in discharge between Wax Lake Delta and the proposed sediment diversions along the Mississippi River, we can use Wax Lake Delta as a model for these diversions. Studying Wax Lake Delta will help us understand how land building and ecological succession will occur for these diversions. This applicability to important coastal management issues as well as the exciting opportunity to learn about understudied deltaic floodplain ecosystems is what has inspired our team to learn as much as we can about this unique system.
See Wax Lake Delta from google earth: