2.1.3 Hydrogeology and groundwater quality

Summary

Datasets used in the groundwater modelling are identified. They include regolith depth, extent of Hunter alluvium, depth to watertable, recharge and hydraulic conductivity datasets.

Sources of data are provided, as well as the methods used to analyse and generate new datasets to inform the modelling. A detailed description of the data analysis and methods to create a recharge surface for the Hunter subregion is provided.

Depth to watertable data from Hunter subregion bores are generally poor, with many bores having only one or two measurements, as well as lack of supporting information and negligible quality assurance. Depth to watertable data are needed to constrain groundwater model results and to produce an interpolated depth to watertable surface for the subregion; however, the lack of confidence in the underpinning data results in increasing uncertainty in derived products.

This section describes some of the datasets that have been used to inform the groundwater modelling of the Hunter subregion. Some are used directly (this includes clipping to the required extent for modelling and/or extracting a specific attribute), whereas others have been derived from multiple data sources for modelling purposes. Not all datasets are reported here. Data used in calibration of groundwater models are reported in companion product 2.6.2 for the Hunter subregion (Herron et al., 2018). The geological model is described in Section 2.1.2 of this product.

Table 6 lists the key datasets used to construct the groundwater model and where they are reported within the Hunter subregion suite of products. The datasets are classified as either ‘source datasets’ (i.e. pre-existing datasets sourced from outside the Bioregional Assessment Programme, but including data sourced from the Programme partner organisations) or ‘derived datasets’ that have been generated by the Programme for groundwater modelling purposes in the Hunter subregion. Details of source datasets and data processing to represent the baseline and additional coal resource developments in the modelling simulations are provided in Section 2.1.6 of this product.

No groundwater quality data are used in the groundwater modelling.

Table 6 Key datasets used for groundwater modelling for the Hunter subregion

Dataset	Source or Derived	Dataset	Details in
Digital elevation model	Derived	Bioregional Assessment Programme (Dataset 1)	Section 2.1.3.2.2
Vegetation height	Source	Caltech/JPL (Dataset 2)	Section 2.1.3.2.2
Geological model	Derived	Bioregional Assessment Programme (Dataset 3)	Section 2.1.2
Recharge	Derived	Bioregional Assessment Programme (Dataset 4)	Section 2.1.3.2.1 and Section 2.1.3.2.1
Regolith depth	Source	CSIRO (Dataset 5)	Section 2.1.3.1.1
Alluvium extent	Derived	Bioregional Assessment Programme (Dataset 6), extracted from Geoscience Australia (Dataset 7)	Section 2.1.3.1.1
Depth to watertable	Derived	Bioregional Assessment Programme (Dataset 8)	Section 2.1.3.1.3
Hydraulic conductivity	Derived	Bioregional Assessment Programme (Dataset 9)	Section 2.1.3.2.2
River network	Derived	Bioregional Assessment Programme (Dataset 10)	Product 2.6.2 Groundwater numerical modelling (Herron et al., 2018)
Groundwater extractions (non-mining)	Source	NSW Department of Primary Industries, NSW Office of Water (Dataset 11)	Product 2.6.2 Groundwater numerical modelling (Herron et al., 2018); Product 1.5 Current water account for the Hunter subregion (Zhang et al., 2016)
Potential evapotranspiration	Derived	Bioregional Assessment Programme (Dataset 12)	Product 2.6.2 Groundwater numerical modelling (Herron et al., 2018)

Section 2.1.3.1 provides details of observed (source) data that have been used for groundwater modelling. The statistical analysis and interpolation section (Section 2.1.3.2) describes the methods for deriving datasets for input into the groundwater model from existing data.

Last updated:

18 January 2019

2.1.3 Hydrogeology and groundwater quality

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ASSESSMENT

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