2.5.1 Methods


Water balances are presented for the Namoi subregion for the reporting periods 2013 to 2042, 2043 to 2072, and 2073 to 2102. Each of the 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.

Water balances are reported for the Namoi groundwater model domain. They comprise recharge, evapotranspiration, non-mining groundwater extractions, mine pumping, surface water – groundwater flux, boundary flux and change in storage water balance terms. The groundwater balances are based on a subset of groundwater model simulations that showed closest agreement to observation data.

Surface water balances are provided for the minimum possible area which incorporates all hydrologically connected cumulative impacts at a point on the Namoi River for which model output is generated (this is 63% of the Namoi river basin). The surface water balances comprise annual rainfall, streamflow, licensed river extractions and a balancing term (residuals). 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:
6 December 2018