1.5.1.1.7 Gaps

There are a number of data gaps which make doing a surface water account for the Hunter subregion challenging. Theses gaps are summarised as follows:

Storages: there are many small storages (e.g. farm dams; mine water storages) across the Hunter subregion for which storage volumes have not been reported. The availability of data on the storage capacities of farm dams across the subregion is not known. Mine water management plans typically report the storage capacities of storages on their sites and this information could be collated to provide a total storage capacity for mining sites.
Inflows: only observations from recorded gauges were used to estimate river inflows. There are ungauged tributary inflows which are not included in the estimate of inflows. These residual contributions can be roughly estimated based on flow differences between upstream and downstream gauges on the Hunter River. Modelled estimates are possible using a landscape water balance model, such as AWRA-L, or other rainfall-runoff models.
Exchanges with groundwater can be difficult to measure and these fluxes are often estimated. River flows include a groundwater component (baseflow) and, in losing reaches, losses to groundwater. Baseflow estimation methods and numerical groundwater modelling are used to quantify these components. Impacts on baseflow from drawdown as a result of mining are unknown, but will be estimated through this BA.
Actual water use data are not available for the entire subregion. Lack of comprehensive metering of take means that getting accurate values of water use across the region is not currently possible. Estimates can be made based on licensed volumes, patterns of use in metered areas and assumptions about basic water rights use.

Last updated:

18 January 2019

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