2.6.2.4 Boundary and initial conditions

Summary

The lateral boundaries of the regional analytic element groundwater model (GW AEM) coincide with the geological basin and are implemented as no-flow boundaries. As the model directly simulates the change to the groundwater system rather than the state of the system, recharge and surface water – groundwater interactions are not included in the regional groundwater model.

The lateral boundaries of the Avon and Karuah models are considered no-flow boundaries.

The spatio-temporal pattern of historical recharge is computed with Australian Water Resources Assessment Landscape model (AWRA-L). This pattern is scaled to match estimates of recharge to the alluvium. For the baseline coal resource development (baseline) and coal resource development pathway (CRDP) runs the recharge pattern is further scaled seasonally to account for climate change.

Potential evaporation is set equal to half of the historical pan evaporation with an extinction depth of 2 m. Water extraction for irrigation, stock and domestic use is not included.