Namoi Catchment Water Study (NCWS) model

The purpose of the NCWS was to assess the cumulative impact of coal mining and CSG developments in the Gunnedah Basin on water resources in the Namoi river basin. Hence the study area covered the surface water catchment (Figure 6). The NCWS model was constructed using MODFLOW-2000 code (Harbaugh et al., 2000). The model has a uniform finite-difference grid, with 1 x 1 km cells, and an active model area of approximately 30,400 km2. The model was constructed with 20 numerical layers to represent Cenozoic, Cretaceous-Jurassic, Triassic and Permian stratigraphic units with a total thickness of greater than 1500 m. As discussed in companion product M07 (as listed in Table 1) for groundwater modelling (Crosbie et al., 2016), the method employed for uncertainty analysis in a BA requires a stable model that can achieve numerical convergence for a wide range of parameter combinations. The NCWS model did not have the stability required for the uncertainty analysis that is required in BA. Significant changes would have to be made to the NCWS model to adapt it for BA purposes and will still retain the limitations of the structured grid.

Last updated:
6 December 2018
Thumbnail of the Namoi subregion

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