CSDMS 2015 annual meeting poster ManLiang

From CSDMS
Presentation provided during CSDMS annual meeting 2015

Reduced-Complexity Model (RCM) for River Delta Formation – Model Assessment and Application

Man Liang, University of Texas at Austin, Texas, United States. manliang@utexas.edu
Corey Van Dyk, University of Texas at Austin, Texas, United States.
Paola Passalacqua, University of Texas at Austin, Texas, United States.
Wonsuck Kim, University of Texas at Austin, Texas, United States.

Abstract:

Understanding deltaic channel dynamics is essential to acquiring knowledge on how deltas respond to environmental changes, as channels control the distribution of water, sediment, and nutrients. In recent years a variety of models have been developed, which provide the basis for the development of a quantitative framework to study deltaic channel dynamics. However, robust metrics are needed to effectively evaluate numerical models and extract relevant information.

In this work we use existing and new metrics, developed in the context of river delta formation, to assess the morphodynamic results of DeltaRCM, a reduced complexity model for delta formation and evolution. Model results are compared to theoretical predictions, field observations and physical experiments. We show that DeltaRCM captures: 1) the geometric growth characteristics of river-dominated deltas such as the fractal growth of channel network, 2) the temporal dynamics of channels at the level of autogenic timescales such as fluctuations in the fraction of wetted surface and loss of channel overlap with time. We also demonstrate how to use a new metric for subsurface structure, sedimentograph, to explore the radially-averaged distribution of coarse and fine sediment. Furthermore, we investigate how deltaic distributary channel networks respond to subsidence and sea-level rise. The results show that without coastal processes such as waves and tides, distributary channel networks exhibit intensified branching in response to continuous relative sea-level rise.


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