Flood inundation models are the best available tools to study and predict flooding. Most of the existing models simulate water movements by solving fluid dynamics equations and are data intensive and computationally costly. Effective and robust flood inundation modelling remains a significant and challenging research subject in hydrology and hydraulics, especially in applications that require inundation assessment for large floodplains, over a long time period, or require multiple simulations.

This PhD research focused on the development and application of a simple conceptual flood inundation model that can be used for rapid and accurate assessment of inundation in large floodplains. The major contributions of this study are listed below:

1. The literature review provides guidance for selecting the most suitable method/model for solving practical flood related problems, taking into account the specific outputs required for the modelling purpose, the data available and computational demands.
2. The TVD (Teng-Vaze-Dutta) model uses high resolution DEM to derive floodplain storages and connectivity between them at different river stages. It has the advantage of low computational cost and can efficiently estimate the maximum or final flood extent in most conditions. Improvements to the model structure have been made to overcome its inherent limitations by implementing mass conservation, reach connectivity and maintaining water balance on the floodplain. These new modules improved model accuracy in areas with hydrologically complex topography, without compromising the model efficiency.
3. The TVD model was coupled with the Australian Water Resource Assessment River System (AWRA-R) model, which is operational in the Australian Bureau of Meteorology for continental scale water accounting. Linking with the TVD model improved accounting for overbank flux and storage, recharge to the groundwater system, and substantially reduced the unaccounted volume.
4. An innovative Floodplain Ecological Response Model (FERM) was developed and coupled with the latest version of the TVD model to support holistic environmental water management. The coupled model provides flood dynamics and quantitative ecological responses and helps water managers to balance benefits and costs and considering environmental and social impacts.
5. Finally, future climate projections were evaluated so that they can be used as inputs to investigate future climate impacts on flooding. Two studies that will lead to this future research were carried out to evaluate datasets and assess methods to produce climate projections.