Mississippi River Management-A Perspective from Sediment Yield in Coastal Louisiana

The Mississippi River system discharges 610 x 10(9) m(3) of water annually into the Gulf of Mexico (GOM). In the past century river engineering and land use practices in the Upper Mississippi River Basin have changed dramatically. A large number of locks and dams were built along the major tributary rivers including Upper Mississippi River, Illinois River, Missouri River, Ohio River, Tennessee River, Arkansas River, and Red River, which has greatly contributed to the reduction in sediment yield to the continental shelf of GOM. Concurrently, the Louisiana Gulf coast has experienced the highest rate of relative sea - level rise of any region in the United States. In the past 50 years land loss rates in Louisiana' s coast have exceeded over 60 km(2) per year, and in the 1990s the rate has been estimated to be between 40 km(2) and 56 km(2) each year. This change represents 80% of the coastal wetland loss annually in the entire continental United States. This paper synthesizes recent work and newly - derived estimates of sediment delivery from six major rivers along Louisiana' s coast. The primary purpose is to review the current land loss situation, sediment availability, and discuss an alternative approach for sediment diversion to offset the sinking coast.