Various models (hydraulic, vegetation and groundwater) have been specifically developed for the Chowilla floodplain to support the development and implementation of environmental management strategies for the Chowilla Icon Site.
Hydraulic Model
A finite difference hydrodynamic model based on Mike Flood, which is a dynamically linked one-dimensional and two-dimensional flood modelling package, has been employed to assess flood enhancement options for the Chowilla Floodplain (DHI Water & Environment, 2006). Two Mike Flood models were made of the Chowilla Floodplain and Anabranch system, one on a 10m 2D grid and the other on a 30m 2D grid. The models were calibrated successfully to a range of flow events, ranging from smaller flows to large flooding flows (see DHI 2006). The description of the development of the numerical model can be found in DHI Water & Environment (2006).
The model has been reviewed by the Department of Water, Land and Biodiversity Conservation (DWLBC) and examination of the overall predictions suggest that the model can be employed for further floodplain modelling works to provide useful information (velocity, water volume and flow distributions) for assessing the feasibility of flow management strategies.
Groundwater Model
A groundwater model has been developed in order to simulate the regional aquifer system. The model is able to:
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Estimate the flux of saline groundwater entering the anabranch creeks from the aquifer system, and when combined with groundwater salinities, the salt load.
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Predict the salt load being delivered to the River Murray under different groundwater management options 100 years into the future.
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Improve the understanding of the hydrogeology of the regional aquifer system and processes in the Chowilla floodplain.
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Assist with broad scale planning of conceptual bore field designs targeting the Monoman Formation, and predict the changes in groundwater levels that would be expected to occur, and the reduction in the salt load being delivered to the River Murray.
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Provide a sound technical basis for evaluating salt loads being delivered to the River Murray from the Chowilla Floodplain.
CSIRO WINDS Vegetation Model
WINDS is a GIS-based spatial model developed by CSIRO that predicts vegetation health based on salt accumulation, and changes in condition resulting from potential management scenarios. The model allows changes in groundwater and flow regime to be modelled across the floodplain, and can predict areas that are likely to benefit and be impacted by surface water and groundwater management options.
Overton, I. Marvanek, S. Jolly, I. (2007) Chowilla Floodplain Vegetation Modelling. CSIRO Land and Water, Adelaide, Australia
DHI (2006) Chowilla Floodplain Hydrodynamic Model: Data Review and Model Development Report. Report prepared for DWLBC (50Mb)
Yan, W. Howles, S.R and Marsden, Z (2005). Chowilla Floodplain Numerical Groundwater Model. Knowledge and Information Division Department of Water, Land and Biodiversity Conservation (3.1Mb).