1.3.3.1 Description


The total number of economic water‑dependent assets in the preliminary assessment extent (PAE) of the Gloucester subregion is 20. There are 13 economic surface water assets and seven economic groundwater assets within the PAE of the Gloucester subregion. The assets are made up from 350 elements including 269 surface water access entitlements and 81 groundwater access entitlements with total share components (a specified share or volume of water that can be extracted within a specified water management area) of 19,880 and 263 ML/year, respectively. This data indicates a much stronger reliance on surface water than on groundwater in the PAE. Table 17 shows the breakdown of water access entitlements (i.e. elements) for surface water and groundwater in the PAE of the Gloucester subregion.

Table 17 Breakdown of water access entitlements for surface water and groundwater in the preliminary assessment extent (PAE) of the Gloucester subregion


Surface water

Groundwater

Water access entitlements (Elements)

269

81

Total share component (ML/y)

19,880

263

Basic water right (stock and domestic)

63

45

Water access right

206

36

There are 13 economic surface water assets and seven economic groundwater assets within the PAE of the Gloucester subregion.

Table 18 shows the number of elements and assets for each category of economic asset within the Gloucester water‑dependent asset register. The locations of the elements are shown in Figure 8 and the locations of the assets (i.e. the grouped elements) are shown in Figure 9. Where known, groundwater bore depth is recorded in the asset and receptor register. Depth is an important attribute associated with these elements and assets because the majority of the alluvium in the Gloucester subregion has a depth of 5 to 10 m, with the maximum being 15 to 20 m. This means that groundwater can be extracted from both the alluvial and fractured rock aquifers. The alluvial aquifers are characterised by high hydraulic conductivity, hence yield high water volume per metre of bore depth; yet many bores are used to extract water from the deeper strata, which are generally lower yielding. Changes in groundwater level (or hydraulic heads, when aquifers are confined) at the individual bore have the potential to be affected by reduction in water pressure in (depressurisation of) the deep strata due to coal seam gas (CSG) and/or coal mining operation. The level of impact (if any) on groundwater in the proximity of these bores will be dependent on the relative changes in groundwater levels compared to overall thickness of water bearing strata, yielding groundwater. This warrants the inclusion of ‘depth’ (where known) in Figure 8 and Figure 9.

Table 18 Elements and assets within each category of economic asset in the Gloucester water‑dependent asset register


Group

Subgroup

Class

Number of elements

Number of assets

Economic

Groundwater management zone or area (surface area)

A groundwater feature used for water supply

0

0

Water supply and monitoring infrastructure

0

0

Water access right

36

2

Basic water right (stock and domestic)

45

5

Economic

Surface water management zone or area (surface area)

A surface water feature used for water supply

0

0

Water supply and monitoring infrastructure

0

0

Water access right

206

5

Basic water right (stock and domestic)

63

8

Figure 8

Figure 8 Location of economic elements within the preliminary assessment extent (PAE) of the Gloucester subregion

(a) Elements within different classes of the ‘Surface water management zone or area’ subgroup. (b) Elements (identified as groundwater bores) within the ‘Groundwater management zone or area’ subgroup. Parts (c) and (d) are zoomed in areas from (b) in the vicinity of the towns of Gloucester and Stroud, respectively. The scale bar under part (d) also applies to part (c).Figure 9

Figure 9 Location of classes of economic assets within the preliminary assessment extent (PAE) of the Gloucester subregion

(a) Economic assets within different classes of the ‘Surface water management zone or area’ subgroup. (b) Economic assets (identified as groundwater bores) within the ‘Groundwater management zone or area’ subgroup. Parts (c) and (d) are zoomed in areas from (b) in the vicinity of the towns of Gloucester and Stroud, respectively. The scale bar under part (d) also applies to part (c), and in parts (b) to (d) the black numbers refer to the depth (m) of the bore.

Last updated:
10 February 2017