2.5.1 Methods


Water balances are presented for the Hunter subregion and subdomains of the subregion for the reporting periods: 2013 to 2042, 2043 to 2072, and 2073 to 2102. Each of the future 30‑year reporting periods includes some level of global warming, with the same variability as in the 1983 to 2012 historical sequence. For each time period, results from the baseline and coal resource development pathway (CRDP) are presented.

One set of water balances is reported for the entire Hunter subregion from the groundwater modelling. It comprises recharge, evapotranspiration, non-mining groundwater extractions, mine pumping, surface water – groundwater flux, boundary flux and change in storage water balance terms.

Two sets of surface water balances are provided at model nodes in the Hunter river basin, selected to quantify hydrological changes due to additional coal resource development over the minimum possible area which incorporates all hydrologically connected cumulative impacts to node 41 (stream gauge 210006) on the Goulburn River and node 6 (stream gauge 210001) on the Hunter River. The surface water balances comprise rainfall, streamflow, licensed river extractions, mine discharges to the river and a balancing term (residuals).

The groundwater water balances are based on 229 of the 1450 groundwater model simulations that showed closest agreement to watertable level and streamflow observation data.

The surface water balances are based on 300 of the 3000 surface water simulations that showed the best agreement with annual streamflow observation data.

Last updated:
18 January 2019