The role of Particle Size in Geological, hydrological and sedimentological controls on wetland loss and gain in the Mississippi River Delta

June 11, 2015, 8:00am PT, 11:00am ET, 3:00pm GMT

            This talk will demonstrate how an understanding of particle size and embayment geomorphology, when coupled with an understanding of sediment geotechnical properties, can lead add in efforts to understand sediment deposition rates. Such information is critical to evaluating whether, when and where, restoration strategies are most likely to be effective.

            The Mississippi River Delta is the largest delta in North America, and one of the largest such systems in on Earth. It supports a wealth of biota- including some of the most productive fisheries in the North America, provides an internationally significant pathway for commerce, hosts oil and gas production, and is home to near two million people. However, the system is also in a state of degradation, with land loss cased by a range of factors that include high rates of relative sea-level rise, reduced sediment deposition, canal, invasive species and eutrophication.  The first part of this talk will show that in one key area, subsidence rates have slowed in recent decades, likely as the result of reduced fluid withdrawal. Restoration of the Mississippi River Delta revolves around a multi-faceted strategy that includes the construction of levees, the direct placement of dredge sediment, and partially diverting the flow of the Mississippi River. The second part of this talk will examine natural, and semi-natural settings that serve as analogues for the, "river diversion," that are envisioned as part of the state's Master Plan for coastal restoration.

Learning Objectives:

• Understand how particle size and embayment geomorphology, when coupled with an understanding of sediment geotechnical properties, can lead add in efforts to understand sediment deposition rates
• Understand why particle size and embayment geomorphology is critical to evaluating whether, when and where, restoration strategies are most likely to be effective