18.1 Groundwater outflow to outside region
a. Groundwater model
The Department of Land Resource Management use the Finite Element Subsurface Flow system (FEFLOW) to estimate the natural water movement to and from the groundwater store within the Daly region.
FEFLOW estimates groundwater movement for the entire extent of the Oolloo aquifer and the Tindall aquifer, which extends beyond the Daly region boundary as shown in the figure below. The volumes reported in this account refer to the natural water movement that occurs within these aquifers within the Daly region boundary.
Map of the groundwater model area relative to the Daly region boundary
The Oolloo and Tindall aquifers are karstic and were modelled as an equivalent porous media with relatively limited storage. The groundwater model was calibrated using regional aquifer parameters to reproduce the observed groundwater levels and discharge to the rivers, as outlined in Knapton et al. (2010).
b. Supporting information
The volume recognised in the water accounting statements (0 ML) represents the volume of groundwater outflow to outside the Daly region boundary from aquifers within the Daly region during the 2011–12 year. In general the regional groundwater flow is from outside the region into the Daly region.
FEFLOW groundwater model.
Department of Land Resource Management.
The groundwater model derives the lateral flux within the Daly region by defining the appropriate water balance zones and calculating the volume of water flowing across each boundary on an annual basis.
Detailed information on the model calibrations are provided in Knapton et al. (2010).
Assumptions, limitations, caveats and approximations
The uncertainty is unquantified.