3.4.6.2 Potential hydrological impacts


3.4.6.2.1 Groundwater

There is 685 km2 of non-remnant vegetation in the ‘Human-modified’ landscape group contained within the zone of potential hydrological change (Figure 33 and Table 8). Non-remnant vegetation in the zone of potential hydrological change (excluding open-cut mine pits) is predominantly classified as ‘Production from relatively natural environments’ (541 km2) or ‘Production from dryland agriculture and plantations’ (140 km2).

The median (50th percentile) estimate of exceeding 0.2 m drawdown due to additional coal resource development includes 371 km2 of human-modified landscapes (Table 20). The area potentially affected by median additional drawdown in excess of 2 m is 92 km2. Median additional drawdown is less than 5 m, with the exception of 32 km2 of human-modified landscapes in the immediate vicinity of the operational areas (Figure 33).

Median drawdown under the baseline is predominantly less than 2 m, covering 223 km2 of the 685 km2 of human-modified landscapes in the zone of potential hydrological change (Figure 34 and Table 19). Median drawdown under the baseline in excess of 5 m, associated with CSG development to the west of The Range proposed coal mine, covers 36 km2 of human-modified landscapes located along the south-western edge of the zone of potential hydrological change (Figure 33).

Figure 33

Figure 33 'Human-modified' landscape group: location of non-remnant vegetation areas contained within the zone of potential hydrological change in the Maranoa-Balonne-Condamine subregion

Baseline drawdown is the maximum difference in drawdown (dmax) under the baseline relative to no coal resource development. Additional drawdown is the maximum difference in drawdown (dmax) between the coal resource development pathway (CRDP) and baseline, due to additional coal resource development. The mine pits in the CRDP are the sum of those in the baseline the additional coal resource development. Landscape classes within modelled open-cut mine pits are not included in this analysis.

ACRD = additional coal resource development, CSG = coal seam gas

Data: Bioregional Assessment Programme (Dataset 1, Dataset 2, Dataset 3, Dataset 4, Dataset 8, Dataset 9)

Figure 34

Figure 34 'Human-modified' landscape group: the top two rows show area (km2) within the zone that exceeds the 5th, 50th and 95th percentile estimates of baseline drawdown and additional drawdown, and the bottom row shows baseline drawdown (m) compared to additional drawdown (m) in each assessment unit

Baseline drawdown is the maximum difference in drawdown (dmax) under the baseline relative to no coal resource development. Additional drawdown is the maximum difference in drawdown (dmax) between the coal resource development pathway (CRDP) and baseline, due to additional coal resource development. Landscape classes within modelled open-cut mine pits are not included in this analysis.

Data: Bioregional Assessment Programme (Dataset 7)

Table 19 ‘Human-modified’ landscape group: area (km2) that exceeds the 5th, 50th and 95th percentile estimates of baseline drawdown in the zone of potential hydrological change


Landscape class

Area in assessment extent

Area in zone of potential hydrological change (excluding modelled open-cut mine pits)

Areaa with baseline drawdown ≥0.2 m

Areaa with baseline drawdown ≥2 m

Areaa with baseline drawdown ≥5 m

5th

50th

95th

5th

50th

95th

5th

50th

95th

Conservation and natural environments

554

1.8

1.3

1.3

1.3

0.9

0.9

0.9

0

0.1

0.7

Intensive uses

788

0.8

0.2

0.4

0.4

0

0.1

0.4

0

0

0

Production from dryland agriculture and plantations

18,992

140

72.8

84.9

100

35.9

51.8

58.2

0.1

7.2

19.5

Production from irrigated agriculture and plantations

3,476

0.8

0.2

0.2

0.2

0.1

0.2

0.2

0

0

0

Production from relatively natural environments

69,833

541

369

497

503

122

169

216

8.0

28.7

58.6

Water

164

0.8

0.7

0.8

0.8

0.3

0.4

0.6

0

0

0.1

Total

93,807

685

444

584

606

159

223

276

8.1

36.1

78.9

aNumbers exclude the modelled open-cut mine pits.

Baseline drawdown is the maximum difference in drawdown (dmax) under the baseline relative to no coal resource development. Landscape classes within modelled open-cut mine pits are not included in this analysis. Due to rounding, some totals may not correspond with the sum of the separate numbers.

Data: Bioregional Assessment Programme (Dataset 7)

Table 20 ‘Human-modified’ landscape group: area (km2) that exceeds the 5th, 50th and 95th percentile estimates of additional drawdown in the zone of potential hydrological change


Landscape class

Area in assessment extent

Area in zone of potential hydrological change (excluding modelled open-cut mine pits)

Areaa with additional drawdown ≥0.2 m

Areaa with additional drawdown ≥2 m

Areaa with additional drawdown ≥5 m

5th

50th

95th

5th

50th

95th

5th

50th

95th

Conservation and natural environments

554

1.8

0.8

1.3

1.8

0

0

0.1

0

0

0

Intensive uses

788

0.8

0.2

0.2

0.8

0

0.1

0.4

0

0

0.3

Production from dryland agriculture and plantations

18,992

140

42.8

79.8

140

1.3

14.0

37.7

1.3

4.4

11.8

Production from irrigated agriculture and plantations

3,476

0.8

0.2

0.2

0.8

0

0.1

0.4

0

0

0

Production from relatively natural environments

69,833

541

203

289

541

17.6

78.0

140

0.8

27.1

61.0

Water

164

0.8

0.4

0.6

0.8

0

0.1

0.2

0

0

0.1

Total

93,807

685

247

371

685

18.9

92.4

179

2.1

31.6

73.2

aNumbers exclude the modelled open-cut mine pits.

Additional drawdown is the maximum difference in drawdown (dmax) between the coal resource development pathway (CRDP) and baseline, due to additional coal resource development. Landscape classes within modelled open-cut mine pits are not included in this analysis. Due to rounding, some totals may not correspond with the sum of the separate numbers.

Data: Bioregional Assessment Programme (Dataset 7)

3.4.6.2.2 Surface water

No surface water numerical modelling was undertaken for the Maranoa-Balonne-Condamine subregion. Some potential hydrological changes may, however, be specified conceptually based on scientific logic as described in Section 3.3 (Potential hydrological impacts).

Last updated:
4 January 2019
Thumbnail of the Maranoa-Baloone-Condamine subregion

Product Finalisation date

2017
PRODUCT CONTENTS