2.6.2.4 Boundary and initial conditions

Summary

The north-eastern spatial boundaries of the Hunter groundwater model are defined by the northern extent of the geological Sydney Basin and a small part of the geological Werrie Basin and are assumed to be impermeable. Elsewhere the model domain extends beyond the subregion boundary in order to minimise boundary effects in the model results, and general-head boundary conditions are used. The model’s base is assumed to be impermeable.

The model’s land surface is subject to rainfall recharge and evapotranspiration, both of which are spatially and temporally varying.

All major rivers, along with some minor reaches, are represented in the model. These represent the points at which the groundwater model interacts with the Hunter surface water model. Perennial rivers may leak to the groundwater system if the watertable is below the river stage, and all rivers may be supplied by the groundwater system if the watertable is higher than the river.

A total of 868 groundwater extraction bores are included in the model. Each is assumed to extract water according to its full entitlement.