An historic vs. present day comparison of longwave pulses to a deltaic system

Scott Hagen, Matthew Bilskie, Robert Twilley, Alexandra Christensen

Thursday 2 july 2015

14:05 - 14:20h at Antarctica (level 0)

Themes: IAHR/COPRI Symposium on Long Waves and Relevant Extremes

Parallel session: 12D. COPRI Symposium: Long waves and relevant extremes

Population densities on deltaic coasts throughout the world are and have been historically high due to rich fertile soils and plentiful natural resources. However, the combination of changes to sediment supply, river flows, subsidence and sea level rise has resulted in the disappearance of deltas around the globe. A first step in understanding the functional response of deltas to these changes involves comparing and contrasting historic (c. 1855) and present day (c. 2005) longwave hydrodynamics in and around two distinct coastal basins in the central Mississippi River Deltaic Plain. River inflows, tides, wind-waves, and hurricane storm surge are simulated through the SWAN+ADCIRC framework. The natural and anthropogenic changes to the patterns of landscape, including subsidence, sea level rise, engineered features, etc., are described by initializing the model geometry and attributes of surface characteristics, as well as setting the initial sea level, for the two periods in time. The response to pulses from extreme hydrologic and hurricane events will be compared and contrasted. This paper lays the groundwork for future assessments through integrated analysis of physical, ecological, and human community modeling.