Surface water model choice

The conceptual model for the Gloucester subregion (see companion product 2.3 for the Gloucester subregion (Dawes et al., 2018)), indicates that coal seam gas (CSG) and large coal mining development has the potential to directly affect the regional groundwater system and that this direct effect can propagate through to the alluvium of the Avon and Karuah river systems. Any impact on the groundwater in the alluvium of those rivers in turn has the potential to affect streamflow (and therefore surface water resources) in the stream networks of the Avon and Karuah rivers. CSG development may impact streamflow if aquifer depressurisation reduces baseflow, while open-cut coal mines will intercept and retain surface runoff which has the potential to affect streamflow directly.

Both the Avon and Karuah rivers are unregulated, gaining streams (Section 2.1.5 in companion product 2.1-2.2 for the Gloucester subregion (Frery et al., 2018)) with relatively small catchment areas. The simulation of river management or routing of streamflow through the river network with a river model is not necessary as the salient features of streamflow can be simulated solely with a rainfall-runoff model (see companion submethodology M06 for surface water modelling (Viney, 2016)).

For these reasons, surface water resources in the Gloucester subregion are modelled using the Australian Water Resource Assessment Landscape model AWRA-L (version 4.5; Viney et al., 2015) only. Gridded output from AWRA-L is accumulated to the model nodes without any lagged routing. That is, there is no explicit transmission delay algorithm.

In all other respects, the surface water modelling in the Gloucester subregion follows the methodology set out in companion submethodology M06 (Viney, 2016).

Last updated:
31 October 2018
Thumbnail of the Gloucester subregion

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