For the Gunbower Forest study, DHI developed a fine scale 2D model of the lower forest using the MIKE 21 hydrodynamic model. The model had a horizontal grid size of 5m and had approximately 430,000 active model cells. The model was used to simulate the flooding patterns in the lower part of the forest and the returns to Gunbower Creek for different combinations of inflow to the forest and flows in the River Murray. The aim of the modelling was to investigate the potential risks of scour at the returns to Gunbower Creek and along the channels leading to the returns. Model results were provided in the form of depths of flooding, velocity and bed shear stress.

In the Macquarie Marshes study, DHI is developing a large scale linked 1D/2D MIKE FLOOD model of the whole marshes, which covers approximately about 180,000 ha. The MIKE 11 1D model represents the main flow channel network, while the MIKE 21 2D model represents overland flooding on the floodplain. MIKE Flood provides a dynamic coupling between the 1D and 2D models. Cross-sections for the 1D model were obtained from LiDAR data with an horizontal resolution of 1m and from ground survey data. Hydraulic control structures, such as weirs, culverts, bridges and gates, were included in the 1D network. The 2D model used the same 1m LiDAR data to generate a 90m grid model to represent the floodplain. The model has undergone preliminary calibration against flow gauge data at a number of stations around the marsh system and against maps of inundation extent derived from satellite images. The model will be used to increase understanding of the complex hydrodynamic behaviour of the marsh system, test a range of water delivery scenarios and provide data for the development of a long term hydrology model of the marshes.

The Gunbower Forest modelling was commissioned by the North Central Catchment Management Authority of Victoria and is conducted under the auspices of the Living Murray program for the Gunbower Forest Icon site. The Macquarie Marshes modelling was commissioned by the NSW Department of Environment, Climate Change and Water and is conducted for the Rivers and Environmental Restoration Program that seeks to maximise the ecological benefits of environmental water.