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Investigation of input reduction techniques for morphodynamic modeling of complex inlets with baroclinic forcing

January 1, 2018

The Mouth of the Columbia River (MCR) is a complex estuary inlet system characterized by a buoyant plume created
by high freshwater flows from the Columbia River into the Pacific Ocean. Data obtained during two major field
campaigns have resulted in a comprehensive dataset of hydrodynamics and sediment transport under high (2013) and
low (2005) river flow conditions. Through the analysis of this data and model simulations obtained with the Delft3D
(MCR) model application we explored the importance and effect of stratification on sand-sized sediment for short- and
long-term sediment transport simulations. Stratification influences the sediment transport through much of the estuary,
and significantly reduces sediment export at the MCR. A correlation analysis reveals that a similar representative tide
that best approximates the spring-neap averaged transport can be selected for both stratified and non-stratified flow.
This correspondence implies that standard morphodynamic tide schematizations (e.g. Lesser, 2009) may also be valid
in the stratified conditions found at MCR and other highly stratified estuaries.