The storage capacity and volume of water stored in some aquifers are often unknown, which means quantifying the available groundwater store is difficult. From a water accounting perspective, availability is better defined in terms of the LTAAEL or the volume held under water access and basic water rights. Typically, the viable, high-demand groundwater resources in NSW have had WSPs developed for them (e.g. alluvial aquifers in the Hunter River; Tomago Tomaree Stockton coastal sands aquifers) to manage the resources within sustainable extraction limits. In fractured and porous rock aquifers where water availability is often poorly quantified, current levels of entitlements may not be sustainable. The embargo on new groundwater access licences in the Hunter subregion since 5 February 2016 reflects the mismatch between availability and existing licensed entitlement volumes. A water sharing plan for the North Coast Fractured and Porous Rock Groundwater Sources is under development.

Catchment recharge estimates are not available for all of the Hunter subregion, however, DPI Water has defined a broad approach for calculating mean annual rainfall recharge (DPI Water, 2015b), which could be applied to the subregion. Estimates of recharge across the subregion using chloride mass balance methods and landscape water balance modelling have been undertaken, which goes some way to addressing the current data gap.

Information on stratigraphy and screened intervals was not available for any of the bores located in the Hunter subregion. This information would provide a more reliable basis for estimating groundwater use by aquifer type.

For bores with water licences, if actual usage data were to become available this would assist in the provision of a more accurate representation of the distribution of groundwater use for some bores within the Hunter subregion. The uncertainty arising from not having accurate groundwater extractions data will be included in the uncertainty analyses undertaken as part of the bioregional assessment (BA) modelling.

Last updated:
18 January 2019