Effects on dredging due to diversions from the lower Mississippi River

This paper presents the development, calibration, and use of a model to ana lyze the long-term effects on dredging due to freshwater diversions along t he lower Mississippi River. The study area includes the Mississippi River f rom Tarbert Landing, Miss., located at mile 306 above Head of Passes, just downstream of the control structure at Old River, to the Gulf of Mexico by way of Southwest Pass. To determine the extent of the riverine effects, an HEC-6 model was developed. HEC-6 is a numerical model used to predict chang es in river profiles due to deposition and scour over a period of time. Mod ification to the HEC-6 code was necessary to accurately reflect the actual processes occurring in the Mississippi River. An option allowing the reintr oduction of dredged material back into the system was added. The calibratio n, choice of parameters, and results obtained from the model are presented and discussed.