1.5.1 Current water accounts

Summary

This section summarises water accounts for the Hunter subregion. It includes information about major water storages and aquifers, streamflow and recharge, surface water and groundwater entitlements, surface water allocations and, where available, actual water use. The Hunter river basin includes regulated and unregulated sections. Unregulated sections include tributaries upstream of Lake Glenbawn, the Goulburn River and its tributaries in the west and smaller tributaries along the regulated sections; the regulated section is mainly regulated by releases from Glenbawn Dam and Glennies Creek Dam. The Macquarie-Tuggerah lakes basin includes three major rivers: Dora Creek, Wyong River and Ourimbah Creek.

There are five major storages used for water supply within the Hunter river basin, although only one of these is physically within the subregion. They have a combined storage capacity of 1254 GL. Since 1991, they have been on average at about 70 to 75% of capacity (~900 GL) at the end of the water year (30 June). There are three main aquifer types that are significant water sources in the Hunter: alluvial, coastal sands and fractured rock. Volumes stored in groundwater aquifers are generally not well known and are not reported here.

Gauging stations are mainly located along the river downstream of the major dams and on major tributaries. Between 2004–05 and 2011–12, mean annual inflow to the Hunter River from gauged tributaries was 1135 GL/year, comprising 560 GL/year from tributaries upstream of Greta and 575 GL/year from the Paterson and Williams rivers. In the Macquarie-Tuggerah lakes basin, mean annual inflow for 2004–05 to 2011–12 was 89 GL/year. The availability of annual mean recharge data for groundwater aquifers was too incomplete to provide a meaningful total.

Water use is managed through a system of water entitlements and water rights. Total surface water entitlements in the Hunter river basin are approximately 767 GL/year. Across all water sources, major water utilities hold the majority of entitlements, about 383 GL/year (50%). General security and unregulated river licences account for another 34% of the entitlement volume (~260 GL/year), with supplementary permits, high security licences, local water utilities and stock and domestic accounting for the remaining licences. Coal mines hold about 47 GL of general, high and supplementary water licences, including 55% of high security licences.

Water use data are not available for much of the subregion, except the Hunter Regulated River water source. Between 2010–11 and 2013–14, the average annual water extraction of 117 GL was 54% ofthe long-term average annual extraction limit (LTAAEL) of 217 GL/year. General security licensed take averaged about 38 GL/year, and use by major utilities averaged 29 GL/year. Annual mine water take varied from 5.6 to 15.7 GL (4 to 13% of all take) during this period. Newcastle was supplied with 63 to 71 GL/year over this same period.

In 2015, total groundwater entitlements for groundwater water sources that intersect or are contained within the subregion were estimated to be about 145 GL, with around 93 GL in alluvial water sources in the Hunter river basin, 45 GL in the Tomago Tomaree Stockton coastal sand aquifers and a little over 6 GL in the Kulnura Mangrove Mountain groundwater sources. This volume encompasses a larger area than the subregion because some water source areas extend beyond the subregion boundary. An estimate of around 128.5 GL/year is obtained when licensed entitlements per bore within the Hunter subregion are summed. Basic water rights for domestic and stock use may account for an additional 7 GL/year.