Coastal Protection and Restoration Authority

Lowermost Mississippi River Management Program

Synthesis and Analysis of LMR Deep Draft Navigation Dredging Activities

This study was conducted by the Water Institute of The Gulf (the Institute) for the Coastal Protection and Restoration Authority of Louisiana (CPRA), as a part of the Lower Mississippi River Management Program.

Despite a growing need for a quantitative sand budget for the Lowermost Mississippi River to inform coastal restoration project design and implementation as well as navigation maintenance dredging operations, our understanding of the character, driving forces, and magnitude of LMR sand transport is limited by a dearth of observational data. An exception to this is the set of surveys that are conducted to support navigation maintenance dredging, and the attendant dredge production data. Dredging to maintain authorized draft clearance in the Mississippi River Ship Channel (MRSC) contributes significantly to the sand transport system in the LMR, and the decades-long dataset that has been collected in support of navigation channel operations provides a unique opportunity to better quantify the sand dynamics in the
LMR.

This report presents an analysis of dredge volumetric production data and the hydrographic dredge support survey data that were collected by the U.S. Army Corps of Engineers (USACE) to support maintenance dredging activities in the Mississippi River Deep Draft Navigation Project/MRSC, from approximately Baton Rouge, Louisiana (River Mile [RM]233 above Head of Passes [AHP]) to the river’s downstream terminus at the Gulf of Mexico (RM 22 Below Head of Passes [BHP]).