Geologic Considerations for the Management of the Transgressive Mississippi River Delta Plain

Investigations into the Holocene geologic framework and processes of the Mississippi River delta plain wetlands, estuaries, and barrier islands have been fundamental to understanding other modern, as well as ancient, deltaic and coastal-plain systems. Models of coastal zone evolution stemming from such research have been required in the exploration for natural resources, documentation of paleo-climatic fluctuations, and more fully establishing process-response links between sediment dispersal pathways, coastal depositional patterns, and sediment mobilization by marine processes. In these regards the scientific merit of investigations across the Mississippi River delta plain is undisputable, and clearly indicated by globally referenced research from the delta plain. Within the last decade however, a need for a more detailed understanding of the delta plain geology and processes has emerged. This interest is driven by the necessity for coastal zone management across this rapidly deteriorating coastal zone, which is heavily industrialized and populated. Numerous nourishment and reconstruction projects have been proposed or implemented for the region in response to the devastating implications of coastal zone degradation. Many more projects are currently being proposed or investigated for their feasibility. Success of these landform management projects will require that the geologic framework be closely integrated into the engineering planning and implementation. Making sound decisions for the emerging concept of Transgressive Management includes identifying paleo sediment suitable for dredging, finding semi-renewable sediment sources along the transgressing coastline, assessing the wetland soil impact of diversions, and predicting subsidence across centennial-scale time frames of relative sea level change.