AB
AB
Pt
Pt
Aw
Aw
Lw
Lw
Pt
Pt
Aw
Aw
Pt
Pt
Pt
Pt
Lw
Lw
Pt
Pt
Pt
Pt
Pt
Pt
Pt
Pt
Aw
Aw
Ad
Ad
Pt
Pt
Pt
Pt
Planted
Planted
Pt
Pt
Pt
Pt
Pt
Pt
Pt
Pt
Pt
Pt
Pt
Pt
WN11
WN09
WN08
WN07
WN06
WN05
WN04
WN03
WN02
WN01
Aw
AB
AB
Ad
AF
AB
LW
Aw
Lw
Lw
Aw
AB
Aw
Aw
AB
AB
AB
Ad
Ad
AB
Ad
Aw
Aw
Ad
Aw
Ad
AB
Ad
AB
356000
358000
360000
62
74
00
0
62
76
00
0
0
200
400
600
800
Metres
Figure 5: Vegetation mapping, quadrat locations and 2013 conservation significant flora locations for the survey area
Author: V. Clarke
Date: 02-12-2013
Datum: GDA 1994
Projection: MGA Zone 50
Drawn: H. Thornton
21097-13-GDR-1RevA_131202_Fig5
Cristal Mining Pty Ltd
Wonnerup North Mineral Sands Project Flora and Vegetation Assessment
Legend
Project Boundary
Trip 1 Quadrat Locations
Trip 2 Quadrat Locations
Conservation Significant Flora
Priority 3
Priority 4
DRF
Astron (2013)
AB - Woodland dominated by marri (Corymbia calophylla) on flats and low rises.
AF - Woodland dominated by marri (Corymbia calophylla) and peppermint (Agonis flexuosa) on the terraces and valley floors of the low undulating Abba Plains.
Ad - Woodland dominated by marri (Corymbia calophylla), peppermint (Agonis flexuosa), sheoak (Allocasuarina fraseriana) and Christmas tree (Nuytsia floribunda) on the mild slopes of the low undulating Abba Plains.
Aw - Dominated by tall shrubland of Melaleuca viminea and woodland of flooded gum and paperbark (Eucalyptus rudis,Melaleuca rhaphiophylla) with the occasional marri (Corymbia calophylla) located on the broad depressions of the
Lw - Dominated by an open woodland of Paperbark (Melaleuca rhaphiophylla) and sedgelands of Cyperaceae and Restionaceae species on broad depressions.
Planted - Planted (non-native) vegetation
Pt - Paddock Trees
Vegetation Mapping
Mattiske Havel (1998)
AB
AF
Ad
Aw
LW
Lw
Cristal Mining Australia Limited
Wonnerup North Mineral Sands Project – Flora and Vegetation Assessment, October 2013
Page | 29
4.2.2.2
Groundwater Dependent Vegetation in the Survey Area
Within the survey area there are no high value-GDEs identified such as caves, Reedia swamps, nor
habitat for significant fauna, such as the orange-bellied and whitebellied frogs ( Geocrinia vitellina
and G. alba), which are listed as ‘vulnerable’ under the EPBC Act. However, according to the
compiled list of southwest flora rated for their ecohydrological tolerance/dependence (Boggs and
Froend 2010) a number of species recorded are rated as being in one of the four classes:
1.
tree and shrub species tolerant of excessive wetness
2.
tree and shrub species optimum on moist sites but intolerant of extremes
3.
wide tolerances with maximum development on dry sites
4.
without clear-cut site preferences.
The comprehensive list denotes those taxa recorded during the survey (Appendix B).
4.2.3
Vegetation Condition
Vegetation condition was assessed using the vegetation condition scale provided in Bush Forever
(Government of Western Australia 2000). In small and linear remnants, vegetation condition is often
a fine mosaic of condition, and Ruabon Road was a good example where vegetation condition could
quickly transition from ‘excellent’ to ‘degraded’ or ‘completely degraded’ and back again over a 20 m
walk. Small patches of historic disturbance exist within a matrix of reasonably intact remnant
vegetation.
The vegetation within the private properties, including the Abba River has been primarily parkland
cleared and used for cattle grazing over a long period of time. The condition is predominantly
‘completely degraded’ according to the Bush Forever scale (Government of Western Australia 2000).
In addition, the private properties include a number of individual trees remaining in the paddocks,
which are described as ‘paddock trees’ and not given a condition rating as they are not considered to
constitute ‘remnant vegetation’. Some paddock trees are planted eucalypt species from eastern
Australia.
Some very limited areas of remnant within the private property on Wonnerup South Road has been
fenced off from stock and have been less degraded; these small areas (<1 ha) were assessed as being
in ‘good to degraded’ condition.
The remnant vegetation along Wonnerup South Road is a fine mosaic of relatively intact remnant in
good to degraded condition; to completely degraded (cleared). The intact areas are still degraded to
some extent with high weed invasion but there remains a suite of representative taxa typical of the
mapped vegetation complex. Vegetation condition mapping is presented in Figure 5.
4.2.4
Weeds
Thirty-eight weeds were recorded during the field survey. Four of these are declared pest plant
species under the Biosecurity and Agriculture Management Act 2007: bridal creeper (* Asparagus
asparagoides), narrowleaf cotton bush (* Gomphocarpus fruticosus), apple of Sodom (* Solanum
linnaeanum), and arum lily (* Zantedeschia aethiopica). Generally, areas that remained intact had
low weed densities and occurrence but areas that were on the grazed private properties or were
historically cleared or degraded, had a variety of weeds that had the potential to further degrade
those areas (where native vegetation remained).
Cristal Mining Australia Limited
Wonnerup North Mineral Sands Project – Flora and Vegetation Assessment, October 2013
This page has been left blank intentionally
D
D
CD
E
CD
Pt
Pt
Pt
Pt
CD
Pt
Pv
CD
CD
CD
CD
D
Pt
D
D - G
CD
E
D
Pt
Pt
Pt
VG
CD
Pt
Pt
Pt
Pt
G
D
VG
Pt
Pv
G
G
D
Pt
Pt
Pt
D
G
CD
Pt
D
VG - G
Pt
G
D - G
Pt
D - CD
CD
G - VG
CD
VG
D
D - CD
D - G
G
D - G
CD
D
D - G
355000
355500
356000
356500
357000
357500
358000
358500
359000
359500
62
74
50
0
62
75
00
0
62
75
50
0
62
76
00
0
62
76
50
0
62
77
00
0
62
77
50
0
0
150
300
450
600
Metres
Figure 6: Vegetation Condition Mapping
Author: V. Clarke
Date: 02-12-2013
Datum: GDA 1994
Projection: MGA Zone 50
Drawn: H. Thornton
21097-13-GDR-1RevA_131202_Fig6
Cristal Mining Pty Ltd
Wonnerup North Mineral Sands Project Flora and Vegetation Assessment
Legend
Project Boundary
Vegetation Condition
E - Excellent
VG - Very Good
VG - G - Very Good to Good
G - VG - Good to Very Good
G - Good
D - G - Degraded to Good
D - Degraded
D - CD - Degraded to Completely Degraded
CD - Completely Degraded
Pt - Paddock Trees
Pv - Planted
Cristal Mining Australia Limited
Wonnerup North Mineral Sands Project – Flora and Vegetation Assessment, October 2013
This page has been left blank intentionally
Cristal Mining Australia Limited
Wonnerup North Mineral Sands Project – Flora and Vegetation Assessment, October 2013
Page | 31
5
Evaluation of Potential Impacts
5.1
Vegetation Clearing
The area of proposed surface disturbance is predominately within cleared exotic pasture (87.5% or
454.5 ha). The remaining 12.5% of the proposed surface disturbance area is comprised of remnant
vegetation (9.2 % or 45 ha), scattered/clumped paddock trees (3% or 16 ha) and non-native planted
vegetation (0.3 % or 2 ha) (Figure 5). Table 6 presents the approximate amount and percentage of
each of vegetation mapped unit that would be cleared as part of the project. The clearing would be
progressive and staged over the mine life (in the order of 8 years).
The majority of the woodland/forest vegetation that would be cleared is fragmented and degraded
due to agricultural land use. The main areas of woodland vegetation that would be cleared for the
project are as follows (Figure 5):
•
the woodland patch (Ad [Abba]) in the northern extent of the project mining area
(approximately 18.5 ha)
•
the woodland patch (AB [Abba]) in the south-western extent of the project mining area
(approximately 5.8 ha would be impacted of the 8 ha patch)
•
the tall shrubland and woodland (Aw [Abba]) fringing the Abba River (approximately 9.5 ha)
•
the woodland and open woodland along Ruabon Road (approximately 0.5 ha).
As described in Section 4.2.2.1, all areas of native vegetation remaining on the Busselton Plain are
deemed to be ‘regionally significant natural areas’ according to the criteria outlined in the Level of
Assessment for Proposals Affecting Natural Areas within the System 6 Region and Swan Coastal Plan
Portion of the System 1 Region (EPA 2006). As outlined in Table 6, the area remaining of the pre-
European extent of the vegetation complexes is critically low (i.e. less than 14% for Ad [Abba] and
less than 2% for other vegetation complexes). None of the vegetation complexes are known to be
represented in existing conservation reserves (Havel and Mattiske 2002; Table 6).
The understorey condition and floristic composition of the vegetation communities within the
agricultural land is degraded to the degree that the vegetation patches mapped as ‘degraded’,
‘degraded to completely degraded’ or ‘completely degraded’ (Figure 6) are considered to have little
or no conservation value as representatives of Abba vegetation complexes. The proposed clearing of
the vegetation in ‘degraded’, ‘degraded to completely degraded’ or ‘completely degraded’ condition
is considered to have a low impact on the regional conservation of the vegetation complexes. A
portion of the remnant in the north of the project mining area is recognised as ‘degraded to good’
condition and a priority plant, Tripterococcus paniculatus P4, was recorded in this remnant.
The tall shrubland and woodland fringing the Abba River (although degraded) provides an ecosystem
function by stabilising the banks of the Abba River. However, the clearing impacts on the riparian
vegetation have been mitigated by reducing vegetation clearing (Aw [Abba] 9.5 ha – Table 6) and
restoration of the riparian vegetation is proposed (Sections 6.1.1 and 6.1.4). In addition, the river
crossings would be constructed as a box culvert or spiral pipe design to maintain flows in the Abba
River.
Patches of vegetation which are in ‘degraded to good’ condition or better (Figure 6) are of greater
conservation value. Relatively intact vegetation occurs in the project area within the road reserve
along Ruabon Road and three priority plants were recorded in the road reserve (Section 5.7). Up to
two individuals of Jacksonia gracillima P3 may potentially be impacted through vegetation clearing
proposed within the road reserve. An additional, potentially undescribed species ( Lepyrodia aff.
Cristal Mining Australia Limited
Wonnerup North Mineral Sands Project – Flora and Vegetation Assessment, October 2013
Page | 32
riparia) was collected from close proximity to the south side of Ruabon Road and has been
submitted to the WA Herbarium due to its atypical features. Of the three individuals noted within
the project area; two are likely to be cleared through the clearing associated with the proposed
widening of Ruabon Road.
Cristal Mining Australia Limited
Wonnerup North Mineral Sands Project – Flora and Vegetation Assessment, October 2013
Page | 33
Table 6 Approximate vegetation areas to be cleared by the project.
Vegetation
Approximate
area (ha)
1
Percentage
of total
project
area
Condition
(Figure 6)
Information on extent (Havel and
Mattiske, 2002)
Assessment of
potential impacts
on vegetation
complexes
Pre-European
area
remaining (%)
Proportion of
the complex
within existing
reserves (%)
AB (Abba) – located on the flats and low rises of the Abba Plains,
dominated by woodland and open forest of Marri (Corymbia
calophylla).
14
3.0
Degraded to
completely
degraded
2
0
Low; potential for
impacts from
direct clearing
AF (Abba) – located on the terraces and valley floors of the low
undulating Abba Plains, dominated by woodland of Marri
(Corymbia calophylla) – Peppermint (Agonis flexuosa) and a tall
shrubland of Myrtaceae – Proteaceae species.
2.5
0.5
Completely
degraded
>1%
(8 ha of 1,901
ha remain)
0
Low; potential for
impacts from
direct clearing
Ad (Abba) – located on the mild slopes of the low undulating Abba
Plains, dominated by woodland of Marri (Corymbia calophylla) –
Peppermint (Agonis flexuosa) – sheoak (Allocasuarina fraseriana)
– WA Christmas tree (Nuytsia floribunda).
18
3.5
Excellent to
completely
degraded
14
0
Low; potential for
impacts from
direct clearing
Aw (Abba) – located on the broad depressions of the low
undulating Abba Plains, dominated by tall shrubland of Melaleuca
viminea and woodland of flooded gum and paperbark (Eucalyptus
rudis – Melaleuca rhaphiophylla) with the occasional Marri
(Corymbia calophylla).
9.5
2
Degraded to
completely
degraded
2%
(140 ha of
9,111 ha
remain)
0
Low; potential for
impacts from
direct clearing
Lw (Ludlow) – located on the fringes of the RFA area, near Ludlow.
The vegetation complex is dominated by an open woodland of
paperbark (Melaleuca rhaphiophylla) and sedgelands of
Cyperaceae and Restionaceae species on broad depressions.
1
0.2
Very good
0
0
Low; potential for
impacts from
direct clearing
SUBTOTAL
45
9.2
Paddock Trees
16
3.0
Non-native planted vegetation
2.0
0.3
Cleared Pasture
454.5
87.5
Cristal Mining Australia Limited
Wonnerup North Mineral Sands Project – Flora and Vegetation Assessment, October 2013
This page has been left blank intentionally
Cristal Mining Australia Limited
Wonnerup North Mineral Sands Project – Flora and Vegetation Assessment, October 2013
Page | 34
Ruabon Road is proposed to be widened by up to a maximum of 3.2 m (or approximately 1.6 m
either side on average) to provide the main access to the Project and to accommodate increased
traffic generated by the high mineral concentrate haulage. Some tree trimming may be required for
line of sight along Ruabon Road (between Bussell Highway and the entrance to M70/360).
The intersection between Ruabon Road and the Bussell Highway and the entrance to M70/360
would also be upgraded in accordance with the City of Busselton and Main Roads Western Australia
requirements. The intersection upgrade would require some minor disturbance to dampland areas
that exist near the Bussell Highway intersection (mapped as Lw [Ludlow] – Figure 5), some of which
is ‘completely degraded’ with parts remaining in relatively ‘good’ to ‘very good’ condition away from
the existing road and not likely to be impacted by the proposed clearing.
In total, the planned road works would require disturbance to approximately 0.5 ha of vegetation
immediately adjacent to the existing Ruabon Road. The impacts of the road widening are considered
to be minimal as a linkage of continuous vegetation would be retained in the road reserve along
Ruabon Road. Also, where possible, this clearing would occur on the southern side of Ruabon Road,
which has generally been mapped as being more degraded than the northern side of the road
(immediately adjacent to the existing road).
No TECs or PECs have been mapped within the project area and none would be adversely impacted
by the proposed clearing. The nearest TECs/PECs are associated with the Ruabon Townsite Nature
Reserve which is located over 2 km north-east of the mining tenement boundary.
Cristal Mining commits to avoid or mitigate impacts from vegetation clearing as described in Section
6. It would be possible to compensate for the residual impacts by providing an offset strategy which
specifically benefits the vegetation complexes that would be impacted by the project.
5.2
Potential Impacts Associated with Groundwater Drawdown
The Atlas of Groundwater Dependent Ecosystems (BoM 2014) indicates the potential occurrence of
groundwater dependent ecosystems in the locality. RPS (2014a) has undertaken a groundwater
impact assessment for the project. RPS (2014a) describes how a perched superficial aquifer occurs
across the site and is typically up to 3.5 m below ground level.
The botanical assessments recorded a number of species across the project area which are known to
occur on moist sites (Section 4.2.2.2). It is considered that some of the existing vegetation in the
surrounding the project area is likely to be at least partially groundwater dependent, in particular
the:
•
the tall shrubland and woodland (Aw [Abba]) fringing the Abba River
•
vegetation growing in association with wetlands or seasonal damplands (mapped as Lw
(Abba) (Figure 5))
•
the woodland patch (AB (Abba)) in the south-western extent of the project mining area
(approximately 5.8 ha would be impacted of the 8 ha patch)
•
the wetland vegetation on the north and south along Ruabon Road near the Bussell Highway
intersection (approximately 0.5 ha).
Abstraction of groundwater would occur to enable mining resulting in a localised groundwater
drawdown effect. RPS (2014a) describe that groundwater drawdown on the superficial aquifer
would be localised (e.g. a drawdown of 1 m not predicted to extend more than 100 m past the
mining tenement boundaries) and temporary in duration (the drawdown would occur when mining
is taking place in a particular area, but would rapidly diminish once mining progresses to the next
area).
Cristal Mining Australia Limited
Wonnerup North Mineral Sands Project – Flora and Vegetation Assessment, October 2013
Page | 35
Placement of saturated sand residues behind the active mining area would result in localised
groundwater mounding. RPS (2014a) describe that a maximum water level increase of 3.5 m is
predicted in the immediate pit area, with an increase in water level of 1 m not predicted to extend
more than 50 m past the mining tenement boundaries. The predicted mounding effects would also
be temporary, with groundwater levels generally expected to recede back to the pre-mining range
within six to twelve months of any particular area being mined.
Potential local and temporary impacts on groundwater dependant vegetation (i.e. a decline in tree
health) may occur as a result of drawdown or raising of the superficial aquifer. Trees within the
mining tenement and within 100 m of their boundaries could potentially be affected, particularly
when groundwater drawdown occurs during the dry times of the year (summer). In order to
minimise these effects, Cristal Mining has committed to the mitigation measures described in
Section 6. In the event that the monitoring indicates that the condition of the adjoining remnant
vegetation is adversely affected, or is likely to be if no action is taken, Cristal would implement
appropriate mitigation strategies or contingency measures. These may include use of water-filled
trenches or spears to locally raise groundwater levels near the vegetation.
RPS (2014a) state that there would be nil to negligible groundwater drawdown extending to the
Ludlow State Forest (greater than 625 m past the mining tenement boundary), Tuart Forest National
Park (greater than 875 m past the mining tenement boundary) and Vasse-Wonnerup System Ramsar
Site (greater than 1,750 m past the mining tenement boundary). Given there would be nil to
negligible groundwater drawdown extending to these reserves, no groundwater dependent
ecosystems in these areas would potentially be impacted.
1> Dostları ilə paylaş: |