CSDMS 2015 annual meeting poster KatherineRatliff

Presentation provided during CSDMS annual meeting 2015

River-ocean interactions: Building a new morphodynamic delta model

Katherine Ratliff, Duke University, North Carolina, United States. k.ratliff@duke.edu
Brad Murray, Duke University, North Carolina, United States.

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Deltas are among the most densely populated landscapes on earth, yet their morphology and inhabitants are increasingly susceptible to natural disasters, in part because of anthropogenic interactions with fluvial, coastal, and wetland processes. Humans have altered the natural course of many rivers via dams, channelization, and artificial levees, which can super-elevate the river above its floodplain. Rates of channel aggradation and backfilling increase as the relative sea-level rise rate (RSLRR) increases, potentially increasing the rate of flooding and avulsions. In order to investigate these effects on river and delta morphology, we have created a new river module based on steepest-decent methodology (Jerolmack and Paola, 2007) that incorporates floodplain deposition and avulsion processes. Preliminary results simulating anthropogenic manipulations of the river (e.g. inhibiting avulsions) show that the effects of artificial levees propagate hundreds of kilometers upstream. Results also indicate that avulsions reach farther upstream under higher RSLRR, and decreased subsidence rates result in more rapid avulsions. As a first step in developing a new 3D ecomorphodynamic delta model, we aim to couple this module with the 3D mode of Sedflux (Hutton and Syvitski, 2008). The new medium-detail model will be based on further model couplings, including vegetation, coastline, and human-dynamics modules. We plain to test, improve, and calibrate model and its parameterizations based on empirical data from the field and laboratory experiments.

Hutton, E, and J Syvitski (2008), Sedflux 2.0: An advanced process-response model that generates three-dimensional stratigraphy, Comput. Geosci. 34(10) 1319-1337.

Jerolmack, D, and C Paola (2007), Complexity in a cellular model of river avulsion, Geomorphology 91(3), 259-270.

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