Calibration of a Marsh-Porosity Finite Element Model: Case Study from a Macrotidal Creek and Floodplain in Northern Australia

Abstract

This study reports on the key findings from the application of a marsh-porosity model to a complex floodplain environment in northern Australia. The paper addresses the fundamental challenges associated with leakage in the marsh-porosity model, which have previously been described in the literature but have received little recent attention and for which limited guidance is available. A sensitivity analysis was carried out by adjusting the marshing parameters on the floodplain and assessing the effect on the simulated depth in Buffalo Creek. The statistical measures showed a significant improvement in the model performance at the most upstream site, using a combination of low porosity and element elimination on the floodplain. These measurements highlight the importance of focusing on the wetting and drying parameters as well as the bed roughness, in calibrating the marsh-porosity models in macrotidal floodplain environments. This paper also presents the parameter values and a summary of how they can be used to assist future practitioners.