Macquarie River floodplain flow modeling: Implications for ecogeomorphology

摘要

The Macquarie Marshes are located on a semi-arid lowland floodplain in south-east Australia. They consist of a complex system of interconnected marshes, swamps, lagoons and braided channels that receive highly irregular flows in a monthly, annual and decadal scale. The wetlands sustain a wide range of flood dependent vegetation that provides important habitat for various endemic species. Previous research has identified that water depth,flood duration and inundation frequency are some of the main controlling factors for many of the floodplain species of the marshes. Over the last few decades discharges in the Macquarie River have been reduced and controlled for industrial, agricultural and domestic water usage, resulting in important ecological deterioration of the marshes. This paper presents a statistical comparison of the preliminary results obtained for implementing a hydraulic-hydrology runoff module (VMMHH 1.0) and a previously implemented 1D/2D coupled hydrodynamic model, MIKE FLOOD (Wen et al. 2013). The VMMHH 1.0 combines a quasi-2D hydrodynamic model, CTSS8 (Riccardi 2000), and a data processing platform designed for use in Microsoft Windows, Simulaciones 2.0. Previous applications include geomorphological changes in large river floodplains and vegetation evolution in estuarine wetlands, showing results consistent with cases of gradual floodplain inundation following overbank flow.