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OPW052025 Report - Part 2
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APPENDIX B
Geotechnical Investigation
Tectonic Geotechnical Pty Ltd
2505 Rev. 1
OPW052025 May 2025
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Page 2
Geotechnical Investigation & Slope
Stability Assessment
Proposed Driveway & Residence, 146 Middle Creek Road,
Federal
9 April
Geotechnical Investigation & Slope Stability 2025 | Ref. 25050-001-Rev0
Assessment
9 April 2025 | 25050-001-Rev0
Page 3
Document Review
Doc No. Revision Prepared By Reviewed By Date Issued
001 0 Robert Gibb Geoff Hurley 9 April 2025
Doc No. Revision Method of Delivery Issued To
001 0 Electronic Bradley Drabsch
Oceantobush Pastoral Trust
([email protected])
001 0 Electronic Jarrod Covey
Subdivisions (Qld)
([email protected])
Prepared By Reviewed By
Robert Gibb BSc (Hons) Geoff Hurley BSc (Hons) MSc DIC C.Geol RPEQ 5716
Senior Engineering Geologist Senior Consultant
Geotechnical Investigation & Slope Stability Assessment
9 April 2025 | 25050-001-Rev0 i
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Executive Summary This report details the results of a geotechnical investigation undertaken for a proposed driveway and future residence at 146 Middle Creek Road, Federal. The investigation was performed by Tectonic for Oceantobush Pastoral Pty Ltd. The geotechnical investigation comprised site mapping by an experienced engineering geologist, excavation of test pits, and laboratory testing. We understand that the preferred site for the residence would be on a topographical high point within the site towards the north-western corner. The driveway would connect from the existing access point off Middle Creek Road to the east and extend along a strongly defined ridgeline running through the site. The crest of the ridgeline was generally rounded, sloping at no more than 8° to either side, estimated to be between about 10 m and 20 m wide along the majority of the alignment, before dropping to steeper slopes, ranging from about 15° to 20°. Beyond this, steeper slopes were present extending down towards the inverts of larger gullies and drainage lines. The site of the proposed house consisted of a relatively wide, gently sloping knob crest; of at least 20 m width at around 5°. Around 10 m from either side of the proposed construction ground slopes increased to about 10° to 11°, increasing to 15° downslope. Test pits TP1 to TP3 were excavated progressively from lower ground to the east/north-east to higher ground in the south-west. Test pits TP1 and TP2 encountered residual soils and extremely weathered (XW) materials to depths of between 0.5 m and 1.3 m below ground level (BGL), underlain thereafter by very low strength to low strength phyllite. Test pit TP3 was positioned below the final rise to the proposed residence, where slopewash was logged to to 0.25 m BGL, then residual soil and XW material of stiff to very stiff, silty clay with varying gravel content to 2.5 m BGL, with phyllite below. Test pits TP4 and TP5 were positioned to the edges of the proposed building area, with a relatively similar subsurface profile logged; of topsoil up to 0.2 m depth, followed by high plasticity, residual silty clay to between 0.4 m and 0.7 m BGL; underlain by highly fractured, medium strength basalt. Diversion drainage will be required around the future residence, and along the driveway alignment such that fill embankments are not allowed to become saturated, and sensitive natural drainage features adjacent are not agitated. Additionally, to minimise the downslope effects of surface waters, channel bars could be installed at key breaks in slope along the alignment, to intercept flows incrementally. In accordance with AS2870-2011, the existing subsurface profile could have a characteristic surface movement due to normal seasonal moisture variation (ys) of up to 75 mm and therefore would be equivalent to Class H2. All footings for the proposed buildings and any ancillary structures (e.g. retaining walls etc.) must penetrate through any future fill and found at least 0.5 m below ground level (existing) into stiff to very stiff residual soils. Footings founded as recommended above in stiff (or stiffer) clays/silts could be designed using a maximum allowable bearing pressure of 100 kPa (high level/pads), or up to 150 kPa maximum allowable end bearing pressure for steel reinforced, concrete bored piles (e.g. if this was preferred for post footings). Following earthworks subgrades are expected to comprise mostly silty clays with varying gravel content and gravelly clays. Laboratory testing for the high plasticity silty clay soils with no visual gravel content returned a CBR values of 1.5 % with a relatively high swell value of 5 %. Where the reactive silty clays with no visual gravel content are present in the subgrade, and a hard surfacing (e.g. concrete) is to be used, a nominal over-excavation and replacement to 300 mm depth with ‘roadbase’ (or similar granular materials) would be required to achieve a design CBR value of 3 %. Alternatively, gravel surfacing could be used with an expectation of some future maintenance. Where the clays contain a significant proportion of gravel or are gravelly clays (i.e. >30 % gravel) a design CBR of 3 % could be adopted, subject to the subgrade passing a ‘proof roll.’ Geotechnical Investigation & Slope Stability Assessment 9 April 2025 | 25050-001-Rev0 ii
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Contents
1. Introduction ............................................................................................................................................................ 1
2. Proposed Development ....................................................................................................................................... 1
3. Aims & Method of Investigation .......................................................................................................................2
3.1 Fieldwork ...................................................................................................................................................................... 2
3.2 Laboratory Testing ................................................................................................................................................... 3
4. Site Description ......................................................................................................................................................3
4.1 Topography................................................................................................................................................................. 4
4.2 Geology ........................................................................................................................................................................ 7
4.2.1 Regional Geology.................................................................................................................................... 7
4.2.2 Subsurface Conditions .......................................................................................................................... 9
4.2.3 Groundwater ........................................................................................................................................... 10
4.3 Laboratory Test Results ........................................................................................................................................ 10
4.4 Surface Drainage ..................................................................................................................................................... 11
4.5 Vegetation ................................................................................................................................................................. 11
4.6 Buildings & Other Structures ............................................................................................................................. 11
5. Slope Stability Assessment ............................................................................................................................... 13
5.1 Existing Conditions................................................................................................................................................. 13
5.2 Slope Stability Assessment.................................................................................................................................. 14
5.2.1 Qualitative Assessment ....................................................................................................................... 14
5.2.2 Numerical Modelling ........................................................................................................................... 16
6. Geotechnical Recommendations ..................................................................................................................... 18
6.1 Site Layout and Geotechnical Constraints..................................................................................................... 18
6.2 Earthworks ................................................................................................................................................................. 19
6.2.1 Site Preparation and Trafficability................................................................................................... 19
6.2.2 Filling ......................................................................................................................................................... 19
6.2.3 Excavations & Batter Slopes ............................................................................................................. 20
6.3 Building Foundations ............................................................................................................................................ 20
6.3.1 Indicative Site Classification .............................................................................................................. 20
6.3.2 Footings .................................................................................................................................................... 21
6.4 Retaining Structures .............................................................................................................................................. 22
6.5 Pavement Design .................................................................................................................................................... 23
6.6 Drainage ..................................................................................................................................................................... 24
6.7 On-Site Effluent Disposal ..................................................................................................................................... 24
7. Limitations ............................................................................................................................................................ 24
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Tables
Table 1: Summary of CBR Laboratory Results .................................................................................................................... 10
Table 2: Stability Risk Levels ...................................................................................................................................................... 14
Table 3: Details of Qualitative Risk Assessment for Property (AGS 2007) ............................................................... 15
Table 4: Retaining Wall Design Parameters.......................................................................................................................... 23
Text Figures
Text Figure 1: Sketch of proposed works (provided by SQ)............................................................................................. 2
Text Figure 2: May 2024 aerial image of lot and surrounds (courtesy Queensland Globe)................................. 3
Text Figure 3: Topography of site and surrounds, hillshade applied (courtesy Qld Globe) ................................ 4
Text Figure 4: Veiw from lowest intermediate knob (LHS) & along driveway alingment above
existing sheds (RHS) ............................................................................................................................................................ 5
Text Figure 5: Looking south-west from saddle (LHS) & north-east at sidelong cut (RHS) ................................ 6
Text Figure 6: View of final rise to house site, looking west ............................................................................................ 6
Text Figure 7: Looking north over proposed house site ................................................................................................... 7
Text Figure 8: Extract of Gympie Surface Geology Map .................................................................................................... 8
Text Figure 9: View of weathered phyllite in cutting adjacent to sidelong section of track ................................ 8
Text Figure 10: Finished excavation - test pit TP3 ............................................................................................................... 9
Text Figure 11: Extract of NC Landslide Hazard Overlay Mapping.............................................................................. 13
Text Figure 12: Extract from Slope/W Analysis (Section A-A'- including adverse groundwater
condition) .............................................................................................................................................................................. 16
Text Figure 13: Extract from Slope/W Analysis (Section B-B'- including adverse groundwater
condition) .............................................................................................................................................................................. 17
Text Figure 14: Concept drainage arrangements ............................................................................................................... 18
Text Figure 15: Footing depth required to minimise the risk of undermining and surcharge loading ......... 22
Appendices
Appendix A Test Pit Logs & Explanatory Notes
Appendix B Laboratory Test Certificates
Appendix C AGS 2007 Practice Note Guidelines for Landslide Risk Management & Qualitative
Terminology for Use in Assessing Risk to Property
Appendix D Limitations
Figures
Figure 1: Site Plan
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1. Introduction This report details the results of a geotechnical investigation undertaken for a proposed driveway and residence at 146 Middle Creek Road, Federal. The investigation was performed by Tectonic for Oceantobush Pastoral Trust, generally in accordance with Proposal P225047-Rev0, dated 3 February 2025. Subdivisions (Qld) Pty Ltd (SQ) are the consulting civil engineers for the driveway layout. The geotechnical investigation comprised a site walk-over survey by an experienced engineering geologist, excavation of test pits at two locations and a ‘scrape’ into a selected existing sideslope; and laboratory testing. This report summarises the results of our investigation and includes a slope stability assessment and recommendations regarding geotechnical matters for the proposed driveway and residence, pertaining to the future building locations, earthworks, retaining structures, footings and drainage. 2. Proposed Development A concept layout sketch had been prepared by SQ at the time of the investigation which indicated initial concepts for the driveway alignment. The driveway would extend from the existing entry point to the east at the frontage to Middle Creek Road, then extend mostly following the ridgeline of a natural spur along the southern edge of the block, then to the north-western corner. A short section to the south of the existing driveway alignment, just prior to the final rise up to the house site (Ref. below) was constructed sidelong across a short section. It is understood that no further notable earthworks would be undertaken, with the driveway largely to follow an existing track. Localised works may be required to facilitate site preparation, grading and drainage however this is not anticipated to exceed about 0.5 m depth/height of cutting/filling. The proposed residence would be located on an elongated knob in the north-west corner, one of the highest topographical points within the allotment. The crest of the knob was relatively wide, and very gently sloping. Therefore, minimal earthworks are anticipated to facilitate the construction of the house, which we understand would be a relatively lightweight building, suspended on short posts. The site does not have access to a potable mains water supply or sewerage, and therefore on-site collection of rainwater in tanks as well as on-site effluent disposal will be required The supplied sketch for the driveway, including annotations discussed on site, is presented below in Text Figure 1 on the following page. Geotechnical Investigation & Slope Stability Assessment 9 April 2025 | 25050-001-Rev0 1
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Approx. house site on
crest of knob
Actual driveway route to
be adopted
Middle Creek Road
Text Figure 1: Sketch of proposed works (provided by SQ)
3. Aims & Method of Investigation
The main aims of the investigation were to address landslide risk and to provide guidance regarding
geotechnical matters for the proposed driveway and residential building. The investigation and report
have been designed to address the requirements of the relevant Noosa Council (NC) codes and policies
regarding slope stability.
3.1 Fieldwork
An experienced engineering geologist from Tectonic undertook an initial site walk-over on 13 March
2025 to visually assess any indicators of past slope instability. The walk-over included assessment of soil
and rock exposures, surface drainage conditions, topography, evidence of erosion, existing structures
and vegetation coverage/condition (as detailed in Section 4 below).
Five test pits were undertaken using a 5.5 tonne excavator with toothed bucket and ripper attachments
to depths of between 0.9 m and 3.2 m below ground level (BGL). One scrape was also completed on the
cut batter where the driveway is sidelong across the slope.
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In situ soil strength was assessed using a pocket penetrometer in test pit sidewalls (where safe access
permitted), and otherwise in relatively undisturbed ‘block’ samples recovered in the test pit spoil.
Small, disturbed samples were recovered in selected horizons from the test pits. The test pits were
backfilled progressively to surface at the time of the investigation, with excess spoil mounded at surface.
Reports of the test pits, along with explanatory notes, are presented in Appendix A. Test locations are
shown in Figure 1, attached at the conclusion of the report text.
3.2 Laboratory Testing
Selected soil samples was dispatched to Chadwick Geotechnics, a NATA accredited laboratory located in
Birtinya for geotechnical testing. Laboratory testing was undertaken in accordance with Australian
Standard AS1289 Methods of Testing Soils for Engineering Purposes and comprised:
▪ One Shrink-Swell Index test for site classification purposes at the house site; and
▪ One single point, four day soak California Bearing Ratio (CBR) test for pavement design purposes.
Laboratory test results are discussed in Section 4.3. The laboratory test certificates are provided in
Appendix B.
4. Site Description
The subject site is formally described as Lot 3 on RP849389 and covers a total area of 56.7 ha. The site
consisted mostly of moderately sloping ground, with a significant area cleared for pastoral activities.
Sporadic trees were present to the centre and north of the site, with denser vegetation over steeper
ground to the south-western corner of the block. A mixture of similar rural allotments and pastoral
blocks were located in the surrounds. Middle Creek Road provides access from the eastern/north-eastern
frontage, and the gazetted (although undeveloped) road corridor for Black Mountain Road was located
to the west/south-west. A relatively recent aerial image of the site is shown in Text Figure 2 below.
Existing sheds
Approx. Lot boundary Middle Ck Rd
Proposed driveway along existing
track
Approx. proposed house site
Black Mountain Road corridor
Text Figure 2: May 2024 aerial image of lot and surrounds (courtesy Queensland Globe)
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4.1 Topography
Publicly available contours for the site are shown below in Text Figure 3.
Highly irregular ground
downslope of driveway
alignment
Approx. driveway
alignment along crest of
ridgelines
Approx. house site on
crest of knob
Saddle in ridgeline
Short section of driveway
sidelong to northern flank
of ridgeline
Text Figure 3: Topography of site and surrounds, hillshade applied (courtesy Qld Globe)
On a wider scale, the site and surrounds consist of moderately steeply incised drainage lines and strongly
defined ridgelines. The south-western boundary of the site (adjacent to the Black Mountain Road
corridor) traces the highest local areas of topography, connecting between a number of elevated knobs.
Ground slopes down from the knobs to the south, and through the site to the north/north-east.
Within the site a strongly defined ridgeline connects the north-western corner (where the residence is
proposed) to the north-eastern corner, where some existing sheds and the access off Middle Creek Road
was present. This ridgeline provides the alignment for the proposed driveway, and connects a number of
intermediate knobs and saddles, generally separating a broad southern and northern drainage regime.
The crest of the ridgeline was rounded, sloping at no more than 8° to either side. The crest area was
estimated to be between about 10 m and 20 m wide, before dropping to steeper slopes, ranging from
about 15° to 20°. Beyond this, steeper slopes were present extending down towards the inverts of larger
gullies and drainage lines.
The surface of the track followed the crest of the ridgeline and was inclined at between about 10° to 15°
mostly, increasing to around 17° to 21° locally just before the crests of the intermediate knobs.
A ‘saddle’ was located approximately central to the driveway alignment, where the gently sloping crest
narrowed slightly, and slopes of about 15° extended over about 15 m to either side.
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To the west of the alignment, a short section of about 60 m length was cut sidelong into the northern
flank of the main ridgeline. The cutting was around 2 m to 3 m in height on the upslope side of the track
and had been left at about 45°. To the northern side of the track at this location, a slightly steeper
ground slope of 18° was noted within 3 m of the edge of the track, which would be consistent with the
alignment being off the crest. Within 6 m of the track, a gully head developed, where ground slopes of
about 27° were measured.
Within the wider northern drainage feature, well downslope of the track, an area of irregular ground was
noted in the contours and observed to be so on site. This type of topography (i.e. where contours
reverse) is an indicator of historic landslide activity, and a number of areas of ‘hummocky’ ground,
leaning trees and exposures of colluvium (ancient landslide deposits) were seen through this area (Ref.
Text Figure 3 on the preceding page).
The site of the proposed house consisted of a relatively wide, gently sloping knob crest; of at least 20 m
width at around 5°. Around 10 m from either side of the proposed construction ground slopes increased
to about 10° to 11°, developing to 15° and steeper downslope. The area around the crest and flanks of
the knob were noted to be relatively consistent, with no signs of previous landslide movement observed
(e.g. irregular or ‘hummocky’ ground, tension cracks, adverse drainage conditions).
General views of the site are given in Text Figures 4 to 6.
Text Figure 4: Veiw from lowest intermediate knob (LHS) & along driveway alingment above existing
sheds (RHS)
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Text Figure 5: Looking south-west from saddle (LHS) & north-east at sidelong cut (RHS)
Text Figure 6: View of final rise to house site, looking west
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Text Figure 7: Looking north over proposed house site
4.2 Geology
4.2.1 Regional Geology
A published geological map for the region1 indicates that the site is underlain by the middle Triassic age
Kin Kin Beds, which are described as “strongly cleaved and commonly kinked mudstone with thin siltstone
laminae, minor volcaniclastic sandstone.” It is noted that some peaks in the wider area are ‘capped’ with
Tertiary age “olivine basalt flows,” which are shown on the regional mapping in areas such as Black
Mountain, about 2.5 km to the south/south-east. An extract of the published mapping is given in Text
Figure 8.
1
State of Qld., Dept. of Natural Resources, Mines and Energy, 1:100,000 Gympie Surface Geology Map, Sheet 9445, 2018
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Approx. site
(Kin Kin Beds)
Example basalt caps
Text Figure 8: Extract of Gympie Surface Geology Map
Across the majority of the driveway, soil exposures were minimal, however at the edges some pale red
brown, pale brown and pale yellow brown silty clays were noted. These are generally consistent with the
residual soils associated with the Kin Kin Beds. In the batter scrape above the sidelong section of
driveway, highly weathered, very low strength phyllite was exposed. A view of this material is presented
below in Text Figure 9.
Text Figure 9: View of weathered phyllite in cutting adjacent to sidelong section of track
There was a change in soil conditions at a slight steepening on the final approach to the house site (Ref.
Text Figure 6 above). Over the steeper section and ground above, soils tended to be dark red brown silty
clays (which are more analogous with weathered basalt), with those below being pale brown grey to pale
yellow brown silty clays (generally consistent with the Kin Kin Beds). Test pit TP3 was present at the break
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in slope towards the base of this rise, and encountered an upper layer of basaltic slopewash,
transitioning to residual soils, extremely weathered (XW) material and weathered phyllite below. The
finished excavation for test pit TP3 is shown below in Text Figure 10 for information.
Residual soils/XW material of the
Kin Kin Beds
Dark red brown coloured basaltic
slopewash
Text Figure 10: Finished excavation - test pit TP3
4.2.2 Subsurface Conditions
Figure 1 (attached) shows the locations of the test pits. The detailed logs and explanatory notes can be
found attached in Appendix A.
Test pits TP1 to TP3 were excavated progressively from lower ground to the east/north-east to higher
ground in the south-west. These were focussed around the crest of the ridgeline forming the alignment
for the proposed driveway, with the results summarised as follows:
▪ Test pit TP1 was located on the northern facing part of the ridgeline approaching the existing sheds.
The pit encountered topsoil to 0.2 m BGL, underlain by residual soil of firm to stiff, silty clay to 0.8 m
BGL, where XW material (described as medium dense gravel and highly weathered phyllite) occurred
to 1.3 m BGL. Following this, highly weathered very low to low strength phyllite was logged with the
test pit terminated due to slow digging at 2.5 m BGL.
▪ Test pit TP2 was excavated at the saddle to the southern edge of the site, where topsoil was logged
to 0.1 m BGL underlain by hard, residual gravelly clay soil, then very low strength weathered phyllite
to 1.1 m BGL, where the phyllite graded to low strength. It was possible under slow excavation
conditions to dig to 2.6 m BGL, where the test pit was terminated.
▪ Test pit TP3 was positioned below the final rise up to the proposed residence (Ref. Text Figure 10
above). The subsurface profile consisted of slopewash to 0.25 m BGL, then residual soil and XW
material of stiff to very stiff, silty clay with varying gravel content to 2.5 m BGL, where highly
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weathered, very low strength phyllite was logged to the termination depth of 3.2 m BGL (limit reach
of machine).
Test pits TP4 and TP5 were positioned to the edges of the proposed building area, with a relatively
similar subsurface profile logged; of topsoil up to 0.2 m depth, followed by high plasticity, residual silty
clay to between 0.4 m and 0.7 m BGL; underlain by highly fractured, medium strength basalt. It was
noted that the weathered basalt ranged to high strength in more intact portions, and hard digging
conditions resulted in termination at depths of between 0.9 m and 1.2 m BGL.
A veneer of localised slopewash was encountered in TP3 close to the transition between the basalt and
the underlying country rock, however no colluvium was encountered in the test pits, or observed on the
slopes within or adjacent to the proposed building or pavement areas.
4.2.3 Groundwater
The development of groundwater over the majority of the driveway alignment, given the position along
the crest if the ridgeline, would be unlikely. However, it is acknowledged that the variable nature of the
soil mass (residual soils, gravelly XW material and fractured upper surface of the phyllite) and the
direction of surface flows towards the site, groundwater seepage could be possible. This would be more
likely at distinct breaks in slope along the driveway (e.g. below the steeper slopes on the edge of the
localised knob flanks).
Groundwater would be rarely encountered other than ‘perched’ flows following periods of heavy or
prolonged rainfall over the proposed house site, being very close to a regional drainage divide and local
high point within the site.
No signs of groundwater seepage (‘springs’) were observed in the vicinity of the proposed construction,
however, slightly wetter soils were logged below the topsoil in test pit TP1.
Groundwater conditions are expected to be reflective of prevailing weather conditions and seepage may
develop, especially at key material boundaries (e.g. soils to rock), and/or rise to shallower depths;
particularly following periods of prolonged or heavy rainfall.
4.3 Laboratory Test Results
The shrink-swell index testing on a sample of the residual basaltic soil in the area of the proposed
residence recorded a value of 6.9 %. This indicates that the soil material is likely to be highly reactive to
normal seasonal moisture variation.
Table 1 below provides a summary of the CBR testing.
Table 1: Summary of CBR Laboratory Results
Optimum
Maximum Dry
Test Location Depth (m) Moisture CBR Swell (%) CBR (%)
Density (t/m3)
Content (%)
BH1 0.0 – 0.5 1.5 28 5 1.5
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CBR testing returned a value of 1.5 % on the residual soils associated with Kin Kin Beds, which will form the majority of the driveway alignment. A relatively high swell value (within the context of the CBR test) of 5 % was recorded. It should be noted that the sample tested was of high silt and clay content and was located close to the contact with the basalt ‘cap’ to the north-western corner of the lot. The residual soils of the Kin Kin Beds elsewhere had a much higher gravel content and/or were closer to the underlying transition to XW material and weathered phyllite. Nonetheless, the materials are expected to be susceptible to strength loss if they become wet. Further discussion on subgrade preparation and design CBR values in the range of materials present at this site is given in Section 6.5. 4.4 Surface Drainage As discussed above, the topographical high point along the western/south-western boundary creates a drainage divide and protection against waters entering the site from that direction. The ridgeline running through the site from west to east also broadly divides the lot into a northern and southern catchment regime. The proposed house site has a negligible catchment for surface water being on an isolated, and high knob within the allotment. The ridgeline upon which the driveway is proposed is rounded, and relatively narrow, with fall away from the alignment to both sides. The catchment for the driveway would generally be from higher parts of the ridgeline above. However, the shape of the ridgeline, being rounded, would generally tend to spread rather than concentrate flows. Where the driveway alignment is sidelong across the upper parts of the ridge flank to the west (Ref. Text Figure 3), the crest is situated about 3 m above the track. A relatively steep drainage line head was located immediately downslope of this area to the north, which would potentially be sensitive to scouring from uncontrolled surface water flows. 4.5 Vegetation The overall allotment consists of a mixture of cleared ground, with occasional trees extending over the central and northern facing areas of the site. To the south-western corner, more dense bushland was observed, including large mature trees. No trees were present along the alignment of the proposed driveway, with the surface being maintained by grazing and periodic sashing. Areas along the immediate edge occasionally included shrubs and vines with sporadic, isolated copses of small trees. Widely spaced, mature trees were present on the crest of the knob to the north-west, >10 m south of the proposed residence. Trees close to the proposed construction areas were relatively ‘plumb,’ however some larger trees in the dense bushland away from the construction areas were variably leaning. Where trees are leaning, this can be (but not necessarily always) a sign of some form of instability. 4.6 Buildings & Other Structures Towards the north-eastern frontage of the site a mixture of older and newer sheds were present. The old shed consisted of a concrete slab, and clad structure above, and was in a dilapidated condition. A relatively recently constructed three bay shed was located to the south-west of the older shed. The new shed consisted of steel portal framing, sheetmetal walls and roof and a concrete ground slab. Geotechnical Investigation & Slope Stability Assessment 9 April 2025 | 25050-001-Rev0 11
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No signs of structural distress which could be attributed to global slope instability were observed in these aforementioned structures. It is noted that the structures present were some distance away from the proposed construction areas covered by this report. Geotechnical Investigation & Slope Stability Assessment 9 April 2025 | 25050-001-Rev0 12
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5. Slope Stability Assessment
5.1 Existing Conditions
NC Landslide Hazard Overlay mapping (Ref. extract in Text Figure 11) indicates that the overall lot
includes areas of Moderate and High susceptibility to landslide. Along the alignment of the future
driveway, and the building area for the proposed house however, a Moderate susceptibility has been
mapped.
Approx. building area for
house
Lot boundary
Text Figure 11: Extract of NC Landslide Hazard Overlay Mapping
It should be noted that the NC map is a broad-scale indication of potential landslide susceptibility only
and is superseded by this site-specific assessment and analysis. Our observations of surface features
relevant to the slope stability assessment are as follows:
▪ Evidence of slope instability was not observed local to the construction areas, although it is
acknowledged that the slopes below the driveway and house site (particularly to the north of the
driveway) would be sensitive to adverse conditions (e.g. uncontrolled surface water, surcharging by
filling, etc.).
▪ In situ residual soils, XW materials and weathered basalt/phyllite were encountered in the test pits at
shallow depth and investigation locations near the construction areas.
▪ No colluvium was logged at the investigation locations and was not observed otherwise in proximity
to the proposed house site or driveway alignment. Localised slopewash was logged in test pit TP3,
however was a veneer (0.25 m thick) and represented a very localised system. Colluvium deposits
were noted in small cuttings and exposed areas downslope and to the north of the proposed
driveway and are likely to represent former landslide activity (Ref. Section 4.1). These areas were
>100 m from the driveway, however.
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5.2 Slope Stability Assessment
5.2.1 Qualitative Assessment
The risk assessment for this project has been conducted following AGS 2007 Practice Note Guidelines for
Landslide Risk Management. Relative levels of risk and their implications are given in Table 2 overleaf
and the Qualitative Terminology for Use in Assessing Risk to Property is also attached in Appendix C.
Table 2: Stability Risk Levels
Risk Level Example Implications (1)
VH Very High Risk Unacceptable without treatment. Extensive detailed investigation and research, planning, and
implementation of treatment options are essential to reduce risk to Low; may be too
expensive and not practical. Work is likely to cost more than value of property.
H High Risk Unacceptable without treatment. Detailed investigation, planning and implementation of
treatment options required to reduce risk to Low. Work would cost a substantial sum in
relation to the value of the property.
M Moderate Risk May be tolerated in certain circumstances (subject to regulators’ approval) but requires
investigation, planning, and implementation of treatment options to reduce risk to Low.
Treatment options to reduce to Low risk should be implemented as soon as practicable.
L Low Risk Usually acceptable to regulators. Where treatment has been required to reduce the risk to this
level, ongoing maintenance required.
VL Very Low Risk Acceptable. Managed by normal slope maintenance procedures.
Note: (1) The implications for a particular situation are to be determined by all parties to the risk assessment and may depend on the nature of
the property at risk; these are only given as a general guide.
Considering the existing site conditions, and subject to the implementation of recommendations given in
Section 6, it is assessed that there would be a Low (L) Risk of global slope instability affecting the
proposed development. Regulators (NC) normally require that a Very Low or Low Risk of landslide
affecting property must be demonstrated to enable development approval. Summarised in Table 3
overleaf is our qualitative assessment of landslide risk for the site. A summary of qualitative terminology
for use in assessing risk to property is attached in Appendix C (taken from AGS 2007).
Geotechnical Investigation & Slope Stability Assessment
9 April 2025 | 25050-001-Rev0 14
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Table 3: Details of Qualitative Risk Assessment for Property (AGS 2007)
Assessed
Hazard Likelihood Consequence Comments
Risk
Taking into account the relatively wide and
gently sloping crest of the basalt ‘cap’ to the
north-western corner of the site, allowing for
1: Proposed House
the offset to the steeper flanking slopes (>10
Site: Shallow or deep
m) and shallow depth to ‘rockhead’ (<1 m
landslide above or Rare Major Low
BGL) it is considered Rare that such
below foundation
movements would occur. The consequence of
levels for building
a deep-seated slide could range to Major, and
therefore the residual risk is Low according to
AGS 2007.
Instability near the crest of the ridgeline over
which the driveway will be constructed would
be considered Unlikely where taking into
account the relatively wide crest over most of
2: Driveway: Shallow the alignment, and negligible earthworks. The
or deep instability in geomorphological shape would limit the
soils/rock on upper Unlikely Medium Low proliferation of chanelised surface water, and
flanks of ridgeline the effects of such instability would be over a
affecting driveway relatively small area where considering the
overall length of the driveway. Therefore, the
consequence would be Medium and the
resultant risk according to AGS 2007 would be
Low.
With access and potential to create favourable
2: Driveway: Through engineered conditions for drainage above the
sidelong section to cut batter, and diversion drainage above, and
west (Ref. Section 4.1), roadside drainage local to the driveway, and
retrogressive slide shallow depth to ‘rockhead’ it is assessed as
Unlikely Minor Low
from steeply sloping Unlikely that such a slide would retrogress
drainage line head and affect the driveway. The limited extent of
within 3 m of road such movement would result in a Minor
edge consequence, and as such the residual risk is
Low as per AGS 2007.
Geotechnical Investigation & Slope Stability Assessment
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5.2.2 Numerical Modelling
In order to provide an estimate of footing depths and assessment of the factor of safety (FOS) against
slope instability for the proposed residence, numerical analysis has been conducted using Slope/W.
Conditions were modelled allowing for the subsurface profile encountered in the test pits and
observations on site. A surcharge of 20 kPa was applied where it is assumed residential construction will
occur (representing a maximum two storey structure or 1 m height of earth fill). A 10 kPa surcharge was
also applied to represent future live traffic loads on the driveway. Sensitivity to groundwater was also
assessed, to give an indication of the FOS under adverse, short-term conditions. It is noted that the
house site is on a high topographical location, and the driveway along the crest of a ridgeline, therefore
the development of consistent long-term groundwater is unlikely.
An extract from the analysis is presented below in Text Figures 12 (proposed house) and 13 (nominal
section through proposed driveway.
Text Figure 12: Extract from Slope/W Analysis (Section A-A'- including adverse groundwater
condition)
Geotechnical Investigation & Slope Stability Assessment
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Text Figure 13: Extract from Slope/W Analysis (Section B-B'- including adverse groundwater condition)
The key points from our analyses are summarised as follows:
▪ Unit weight and shear strength parameters adopted for the soil and weathered rock strata were
estimated based on our interpretation of the geotechnical investigation data and were typically
within the mid-range of values recommended for similar materials in Appendix D of Australian
Standard AS4678-2002 Earth Retaining Structures.
▪ Analyses were undertaken for a range of entry and exit points to assess global slope instability for
the subsurface conditions encountered during the investigation (as outlined above. The analyses
returned acceptable FOS values of at least 1.5 for long term conditions, which also included
considered of an adverse short term groundwater condition.
▪ Analysis indicates that the development would achieve the minimum FOS requirement of 1.5 (long-
term conditions) for hillside developments as required by the SCC Landslide Hazard and Steep Land
Overlay Code.
Our analyses indicate that an acceptable FOS against instability could be achieved for proposed
development and that there would be a Low Risk of slope instability affecting the proposed residence
subject to implementation of the recommendations outlined in Section 6.
Geotechnical Investigation & Slope Stability Assessment
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6. Geotechnical Recommendations
General recommendations to help maintain the stability of the site are given in the document Some
Guidelines for Hillside Construction, which is attached in Appendix C.
6.1 Site Layout and Geotechnical Constraints
It is noted that detailed building and pavement design plans were not available at the time of preparing
this report, however building works should be limited to the areas described in Section 2, and finalised
plans should be reviewed by Tectonic prior to construction.
In general, it is expected that for the driveway and future house, significant earthworks would not be
required, other than about 0.5 m depth/height of cut/filling to achieve drainage gradients etc. Deeper
isolated excavations may be required for underground services and footings.
While there would generally be no limitations around earthworks over the proposed house site (provided
the offsets described in Section 4.1 are maintained), or over the majority of the driveway; where the
driveway is sidelong across the ridgeline flank to the west, fill should be limited to no more than 0.5 m
height.
In the sidelong area, which extends over a distance of about 60 m, it is recommended that the soil
materials are trimmed back to 1V:2H near the crest, however the weathered phyllite towards the toe
could be maintained at 1V:1H in the long term. Diversion drainage should be installed above the cut
batter slope, which could take the form of a suitably sized swale, preferably taken to discharge away from
the driveway to the south. In this area, where possible, surface waters should not discharge in an
uncontrolled fashion to the gully head downslope (within about 3 m distance). A rock lined dissapator
would be recommended for the gully head to prevent future erosion, or alternatively surface waters
could be directed around this, to disperse over other slopes to the north-east.
Additionally, to minimise the downslope effects of surface waters, channel bars could be installed at key
breaks in slope along the alignment, to intercept flows incrementally. This concept is shown in Text
Figure 13 below.
Indicative channel bar
locations
Diversion drainage above
cut
Text Figure 14: Concept drainage arrangements
Geotechnical Investigation & Slope Stability Assessment
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6.2 Earthworks 6.2.1 Site Preparation and Trafficability Any organic rich topsoil, firm/loose (or weaker) soils, overly wet materials must be stripped and removed from the proposed building footprint and pavement subgrades. Topsoil materials must not be used in structural fill; however, may be placed across landscaping areas. It is recommended that following removal of unsuitable materials all building/pavement subgrades be proof rolled using a minimum 4 tonne rubber tyred vehicle to identify any ‘soft spots’ in the presence of a geotechnical RPEQ. Any such soft spots should be excavated and replaced with select fill material, constructed as recommended in Section 6.2.2. Based on visual appraisal and the subsurface investigation findings, excavations to remove unsuitable materials are anticipated to be minimal; however, deeper pockets of unsuitable materials may be present in isolated locations. The subgrade materials exposed after site stripping are expected to comprise silty clays with varying gravel content. These soils could be subject to strength loss from repetitive vehicle loading (particularly from rubber tyred plant) or if they become wet. Due to the potential for poor trafficability during and after wet periods, placement of a minimum 150 mm thick granular working platform may be required, particularly along access ways and any laydown areas. The basaltic soils in the proposed building area for the residence can variably grade to clayey silts, which are sensitive to repeated tracking and moisture variation. Therefore, wherever possible during construction, light plant should be utilised and trafficking of subgrades should be minimised. Subgrades should be graded and ‘sealed off’ at the end of each working day using a smooth drum roller to prevent ponding of water and aid shedding of runoff, so that the risk of subgrade softening is minimised. Earthworks would likely be particularly prone to disruption due to wet weather, which should be considered accordingly during project planning. The site should be graded to shed surface water runoff away from construction areas. It should be noted that during wet weather, the natural soils may cause turbid stormwater run-off. Appropriate erosion and sediment control measures must be installed prior to commencement of earthworks at this site. 6.2.2 Filling Site soils, where free of deleterious materials (e.g. vegetation, oversize etc.), are expected to be suitable for re-use as structural fill, subject to appropriate moisture adjustment. Due to the mostly high plasticity and potentially highly reactive nature of the site soils, it is recommended that the high plasticity clays and high-liquid limit silts should not be reused as structural fill onsite; however, they could be used as non-structural fill (e.g. in landscaping areas, batters etc.). Reuse of high plasticity clays and silts will have adverse implications for site classification, pavements (low CBR values) and footing design. Should importation of fill be required, it is recommended that such fill should comply with the following: ▪ Minimum CBR of 10% ▪ Maximum plasticity index of 15% ▪ Shrink-swell index ≤ 1% ▪ Maximum particle size of 100 mm Any new fill materials should be compacted at moisture contents within the range of -2% to +2% of optimum moisture content for Standard Compaction. Geotechnical Investigation & Slope Stability Assessment 9 April 2025 | 25050-001-Rev0 19
Page 26
Further details regarding filling (including re-use of existing materials, and imported select fill) are given in Australian Standard AS 3798-2007 Guidelines on Earthworks for Commercial and Residential Developments. Select fill should have a maximum particle size of 100 mm for an uncompacted layer thickness of 200 mm and shall be compacted by repeated rolling with a small compactor to achieve a dry density ratio of at least 95 % of the Standard Maximum Dry Density for cohesive soils, or 70 % Dry Density Index for any imported cohesionless soils. Following stripping of topsoil and any unsuitable soils, fill must be ‘benched’ into the natural soil, over filled by 0.5 m (horizontally) and then trimmed back to the well compacted material. 6.2.3 Excavations & Batter Slopes Excavations within the residual soils to the test pit termination depths should be achievable using small to medium sized conventional earthmoving plant (e.g. 5 to 14 tonne excavators) with toothed buckets. Ripping attachments will be required in confined excavations to penetrate the phyllite ranging to low strength and the upper weathered basalt layers, with localised hydraulic breaking possible where larger high strength (or stronger) basalt corestones are encountered within the site for the proposed residence. Temporary, non-surcharged batter slopes up to 1 m high may be formed at 1V:1.H in stiff (or stiffer) clays provided groundwater seepage is not encountered. Flatter batters may be required if groundwater seepage is encountered, or if earthworks are undertaken during a period of heavy rainfall. Deeper unsupported temporary batters should be assessed by a geotechnical RPEQ during construction. Permanent batter slopes less than 1 m high should be constructed at a maximum grade of 1V:2H in stiff (or stiffer) clays and future controlled fill (on slopes < 10°). Permanent soil or fill batters will require erosion protection (e.g. revegetation or surface protection). Where such battering is not possible, retention will be required. Existing slightly over-steep batters between the building platforms should be trimmed back to the permissible grades as outlined above or retained. Any excavation required adjacent to existing structures will need to be specifically designed to ensure that the structures are not undermined. The above recommendations do not supersede any existing safety regulations or legislation applicable to excavations (e.g. limits on personnel entry into trenches). 6.3 Building Foundations 6.3.1 Indicative Site Classification In accordance with AS2870-2011, the existing subsurface profile would have a characteristic surface movement due to normal seasonal moisture variation (ys) of up to 75 mm and therefore would be equivalent to Class H2. It should be noted that the predicted order of movement is based on the existing natural soil profiles (i.e. no additional cutting or filling), and moisture content changes within soils due to normal seasonal moisture variations only. Site classification would need to be assessed by a suitably qualified and experienced person following completion of building plans and finalisation of earthworks details. Due to the reactive nature of the site soils, it would be prudent to implement the following practices to prevent changes in soil moisture (given overleaf): Geotechnical Investigation & Slope Stability Assessment 9 April 2025 | 25050-001-Rev0 20
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▪ Prevent drying of the clay soils during construction by minimizing exposure of cut batters and
excavation subgrades. This may be achieved by measures such as covering batters with
geosynthetic filter fabric (‘Bidim’) or HDPE (‘black builders plastic’), staging earthworks to minimize
soil exposure before covering with structures or surface layers (e.g. topsoil), and placement of
‘blinding’ layers across excavation subgrades and footing bases (e.g. crushed rock or concrete). If
clayey subgrade materials are allowed to ‘dry out’, significant softening could occur on ‘wetting up’,
resulting in subgrade strengths less than expected for stiff clays.
▪ Install and maintain temporary drainage to prevent saturation of the site during construction.
▪ Seal the ground surface around building perimeters (e.g. concrete or paved pathway).
▪ Plant shrubs/trees at least a distance from buildings equal to the mature height of the shrub/tree.
▪ Install landscaping along proposed roads that will minimise the potential for adverse impacts on
pavements and kerbs (e.g. preferably shrubs, grasses, etc.).
▪ Maintain stormwater drains to prevent overflow into soils.
6.3.2 Footings
Footing requirements would be subject to geotechnical review once building design plans and
earthworks details are available for the proposed residence; however, the following may be used in
developing structural design details.
All footings for the proposed buildings and any ancillary structures (e.g. retaining walls etc.) must
penetrate through any future fill and found at least
0.5 m below ground level (existing) into stiff to very stiff residual soils.
It is anticipated that normally dimensioned, high-level footings or mass poured shallow concrete pads
(‘bucket piers’) could be considered for most of the building. Footings founded as recommended above
in stiff (or stiffer) clays/silts could be designed using a maximum allowable bearing pressure of 100 kPa
(high level/pads), or up to 150 kPa maximum allowable end bearing pressure for steel reinforced,
concrete bored piles (e.g. if this was preferred for post footings). For deeper piles taken to socket into the
underlying very low strength (or stronger) weathered basalt, a maximum allowable bearing pressure of
400 kPa could be adopted for design.
All footings should found such that they are not adversely affected by any adjacent excavations, trenches,
or retaining walls that are not designed to support building loads.
Footings should found at least below a plane extending 1 m horizontally from the base of
trenches/excavations/retaining walls, then rising up at 1V:1H, as illustrated in Text Figure 14.
Geotechnical Investigation & Slope Stability Assessment
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Text Figure 15: Footing depth required to minimise the risk of undermining and surcharge loading Footing bases must be cleaned following mechanical excavation to expose undisturbed materials over the full base area. If the building design requires a socket into the underlying weathered basalt for some of the footings, it would be essential that the contractor have suitably sized rock augers and downhole breaking tools. Where bored piles are utilised, it is recommended that the piling contractor have a ‘mud bucket’ or similar device to enable clean out of the pile bases. ‘Spinning’ of the augers is not acceptable and will not sufficiently remove drill spoil from pile bases. A suitably qualified and experienced structural or geotechnical RPEQ should inspect the footing excavations to confirm appropriate foundation materials and cleanliness prior to pouring concrete. If any ground conditions encountered during construction are found to differ from those noted above, Tectonic must be notified immediately, and an inspection carried out to determine if changes to footing design are required. 6.4 Retaining Structures Retaining structures greater than 1 m high, or those required to support surcharge loads or sloping backfill, will require engineer design and certification of construction. Retaining wall design should be carried out in accordance with AS4678-2002 Earth retaining structures. Design for retaining structures could be carried out using a pressure distribution applicable to the wall type and based on the parameters listed in Table 4. These values do not include allowance for hydrostatic pressures nor transient (e.g. construction) or adjacent footing loadings. Geotechnical Investigation & Slope Stability Assessment 9 April 2025 | 25050-001-Rev0 22
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Table 4: Retaining Wall Design Parameters
Unit Friction Lateral earth pressure coefficients
Retained material weight angle Ka Ko Kp
(kN/m3) (Degrees) (Cantilever wall) (Non-yielding wall)
Stiff (or stiffer) 18 25 0.41 0.58 2.46
Residual Soils
Very Low Strength 21 33 0.29 0.46 3.39
(or Stronger)
Weathered Phyllite
Very Low Strength 21 35 0.27 0.43 3.69
(or Stronger)
Weathered Basalt
Future Fill * * * * *
Note: * Depends on fill material type and level of compaction.
At a minimum, retaining structures must be founded as per the recommendations in Section 6.3.2 above
with the footings also designed to account for lateral loads imposed by the retaining wall. Detailed
design must include an assessment of internal and global stability, together with required bearing
capacity and founding depth, by the retaining wall design engineer.
6.5 Pavement Design
Pavement design will be dependent upon the actual subgrade materials present after earthworks.
Following earthworks subgrades are expected to comprise mostly silty clays with varying gravel content
and gravelly clays. Laboratory testing for the high plasticity silty clay soils with no visual gravel content
returned a CBR values of 1.5 % with a relatively high swell value of 5 %.
Where the reactive silty clays with no visual gravel content are present in the subgrade, and a hard
surfacing (e.g. concrete) is to be used, a nominal over-excavation and replacement to 300 mm depth with
‘roadbase’ (or similar granular materials) would be required to achieve a design CBR value of 3 %.
Alternatively, gravel surfacing could be used with an expectation of some future maintenance. Where the
clays contain a significant proportion of gravel or are gravelly clays (i.e. >30 % gravel) a design CBR of
3 % could be adopted, subject to the subgrade passing a ‘proof roll.’
Pavements may be designed using the CBR value of the imported fill material where such filling is at least
500 mm deep.
The performance of pavements should also be considered against the anticipated ground surface
movements, taking normal seasonal moisture variation into account, as discussed in Section 5.2.1 above.
Consideration could be given to subgrade stabilisation using lime or cement treatment for hard surfaced
pavements traversing the basaltic soils towards the upper parts of the site. Input and advice from a
pavement design specialist should be sought in this regard to confirm volumes of mixing etc.
Proposed pavement subgrades must be ‘proof rolled’ and visually assessed by an experienced RPEQ to
ensure no heaving or unacceptable subgrade deflection occurs. Should heaving or deflection occur,
excavation of ‘soft spots’ may be required, followed by reinstatement with compacted select granular fill.
Geotechnical Investigation & Slope Stability Assessment
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The recommended design CBR value is applicable to properly drained subgrades only, and must be confirmed by subgrade inspection and testing, if necessary, by an experienced engineer following earthworks. ‘Properly drained subgrades’ require open graded drains, site grades that shed water and prevent ponding, and subsurface drains adjacent to pavements. 6.6 Drainage During construction, temporary open swales and diversion drainage may be required to divert seepage and/or runoff away from the construction area. Permanent site drainage must be installed to ensure that stormwater runoff is directed away from structures and footings around the residence (e.g. positive gradients and/or channel drains), and also not allowed to flow over fill embankments along the driveway and agitate steeper slopes close by on the downslope side. Uncontrolled flow of stormwater over cut/fill batters has the potential to saturate and weaken the soil material, potentially leading to erosion and slumping failure; and where allowed to impact the existing natural slopes may initiate retrogressive failures. Subsurface drainage must be installed behind any retaining walls (e.g. slotted ‘aggi’ pipe wrapped in filter ‘sock’ placed in gravel backfill). Surface water should be prevented from infiltrating the subsurface drainage by placement of a minimum 300 mm thick clay ‘plug’ above the drainage media (separated by geosynthetic filter fabric), or construction of a concrete swale, or similar. Depending on matters such as the extent of drainage installed and site-specific groundwater conditions, the designer must assess hydrostatic pressure to be accounted for in the design of the retaining structure. All excess stormwater collected around the proposed development area must be directed by pipes or surface channels (e.g. rock lined ‘dry creek’ beds) to discharge at least 10 m downslope and away from any structure or embankment. A surface dissipation device such as rock weir or rock lined contour drain must be installed at the stormwater outlet(s). Subsurface disposal of stormwater must not be undertaken (including infiltration pits). 6.7 On-Site Effluent Disposal Effluent disposal land application areas will require investigation and design but must be located downslope (or oblique across the slope) and not less than 10 m from any structures, retaining walls, cut/fill batters or the proposed driveway. 7. Limitations Your attention is drawn to the document Limitations, which is included in Appendix D of this report. The statements presented in this document are intended to advise you of what your realistic expectations of this report should be, and to present you with recommendations on how to minimise the risks associated with the services provided by Tectonic for this project. Geotechnical Investigation & Slope Stability Assessment 9 April 2025 | 25050-001-Rev0 24
Page 31
0 20 40 60 80m | LEGEND APPROX. TEST PIT (TP) & BATTER SCRAPE ENT PROJECT (BS) LOCATIONS OCEANTOBUSH PASTO GEOTECHNICAL INVESTIGATION PROPOSED DRIVEWAY & RESIDENCE APPROX. SLOPE/W SECTIONS e é : OF NEARMAP, DATED 6 OCTOBER PROJECT Ni DOC NO, FIGURE NO. REVISION SCALE eee as 0s cs ac
Page 32
Extracts of the Base architectural drawings is shown in context in Text Figure 1 on the following page.
Appendix A
Test Pit Logs & Explanatory Notes
Geotechnical Investigation & Slope Stability Assessment
9 April 2025 | 25050-001-Rev0 25
Page 33
Test Pit No.
TP1
Page 1 of 1
Engineering Log - Test Pit Project No.: 25050
Client: Oceantobush Pastoral Trust Commenced: 13/3/2025
Project Name: Proposed Driveway & Residence Completed: 13/3/2025
Hole Location: 146 Middle Creek Road, Federal Logged By: RKG
Hole Position: 480239.0 m E 7079658.0 m N MGA2020 Zone 56 Checked By: ACD
Equipment Type and Model: 5.5t Excavator RL Surface: No survey
Excavation Dimensions: Datum: AHD Operator: Bebrok
Excavation Information Material Description and Observations
Relative Density
Classification
Shear
Penetration
Pocket
Consistency
Graphic Log
Samples Material Description Structure and
Penetrometer Vane
Condition
Recovery
Tests soil type: plasticity or particle characteristics, Additional
Moisture
UCS Test
Symbol
Method
secondary and minor components, colour Observations
Water
Remarks RL Depth (kPa) (kPa)
(m) (m)
100
200
300
400
500
50 100 150 200
Silty CLAY, (TOPSOIL) high plasticity, pale 0.00: TOPSOIL
brown, trace fine to coarse sized subangular w<
F
gravel PL
CH Silty CLAY, high plasticity, pale red brown, 0.20: RESIDUAL
80
with fine to medium sized subangular gravel
100
w = F to
PL St
100
0.5
w<
St
PL
Interlayered Clayey GRAVEL, fine to coarse 0.80: EXTREMELY
sized angular, and PHYLLITE, moderately WEATHERED MATERIAL
weathered, grey, stained orange brown, very
1.0 low strength
M MD
TECTONIC 3.00.2 LIB.GLB Log 1 TECTONIC BOREHOLE 25050.GPJ <<DrawingFile>> 2/4/2025 16:32 10.02.00.04 Datgel Lab and In Situ Tool - DGD | Lib: Tectonic 3.00.2 2021-03-30 Prj: Tectonic 3.00.2 2021-03-30
EX
PHYLLITE, highly weathered, grey, stained 1.30: PHYLLITE
orange brown, very low strength
1.5
becoming low strength, recovered as coarse
sized angular gravel & cobbles,
2.0
2.5
Hole Terminated at 2.50 m
Target depth
3.0
Method Penetration Water Samples and Tests Moisture Condition Consistency/Relative Density
N - Natural Exposure VE - Very Easy Level (Date) U## - Undisturbed Sample (## mm) D - Dry VS - Very Soft
X - Existing Excavation E - Easy DS - Disturbed Sample M - Moist S - Soft
BH - Backhoe Bucket Inflow BDS- Bulk Disturbed Sample W - Wet F - Firm
R - Ripper F - Firm VSt - Very Stiff
EX - Excavator H - Hard H - Hard
RH - Rock Hammer VH - Very hard VL - Very Loose
Plastic Limit
L - Loose
Classification Symbols < PL MD - Medium Dense
and Soil Descriptions = PL D - Dense
Based on Unified Soil < PL VD - Very Dense
Classification System Fr - Friable
Page 34
Test Pit No.
TP2
Page 1 of 1
Engineering Log - Test Pit Project No.: 25050
Client: Oceantobush Pastoral Trust Commenced: 13/3/2025
Project Name: Proposed Driveway & Residence Completed: 13/3/2025
Hole Location: 146 Middle Creek Road, Federal Logged By: RKG
Hole Position: 480064.0 m E 7079416.0 m N MGA2020 Zone 56 Checked By: ACD
Equipment Type and Model: 5.5t Excavator RL Surface: No survey
Excavation Dimensions: Datum: AHD Operator: Bebrok
Excavation Information Material Description and Observations
Relative Density
Classification
Shear
Penetration
Pocket
Consistency
Graphic Log
Samples Material Description Structure and
Penetrometer Vane
Condition
Recovery
Tests soil type: plasticity or particle characteristics, Additional
Moisture
UCS Test
Symbol
Method
secondary and minor components, colour Observations
Water
Remarks RL Depth (kPa) (kPa)
(m) (m)
100
200
300
400
500
50 100 150 200
Clayey SILT, (TOPSOIL) high liquid limit, pale F to 50 0.00: TOPSOIL
brown, trace fine sized angular gravel & St 100
CI 0.10: EXTREMELY
rootlets WEATHERED MATERIAL
Gravelly CLAY, medium plasticity, pale red w<
brown, fine to coarse sized angular to PL H
600
subangular gravel
0.5 0.50: PHYLLITE
PHYLLITE, highly weathered, grey, stained
pale red brown & yellow brown, very low
strength, recovered as fine to coarse sized
subangular gravel
1.0
Not Encountered
becoming low strength, pale grey, recovered
as coarse sized angular gravel & cobbles
TECTONIC 3.00.2 LIB.GLB Log 1 TECTONIC BOREHOLE 25050.GPJ <<DrawingFile>> 2/4/2025 16:32 10.02.00.04 Datgel Lab and In Situ Tool - DGD | Lib: Tectonic 3.00.2 2021-03-30 Prj: Tectonic 3.00.2 2021-03-30
150-200mm size
EX
1.5
2.0
2.5
Hole Terminated at 2.60 m
Very slow digging below 1.1m
3.0
Method Penetration Water Samples and Tests Moisture Condition Consistency/Relative Density
N - Natural Exposure VE - Very Easy Level (Date) U## - Undisturbed Sample (## mm) D - Dry VS - Very Soft
X - Existing Excavation E - Easy DS - Disturbed Sample M - Moist S - Soft
BH - Backhoe Bucket Inflow BDS- Bulk Disturbed Sample W - Wet F - Firm
R - Ripper F - Firm VSt - Very Stiff
EX - Excavator H - Hard H - Hard
RH - Rock Hammer VH - Very hard VL - Very Loose
Plastic Limit
L - Loose
Classification Symbols < PL MD - Medium Dense
and Soil Descriptions = PL D - Dense
Based on Unified Soil < PL VD - Very Dense
Classification System Fr - Friable
Page 35
Test Pit No.
TP3
Page 1 of 1
Engineering Log - Test Pit Project No.: 25050
Client: Oceantobush Pastoral Trust Commenced: 13/3/2025
Project Name: Proposed Driveway & Residence Completed: 13/3/2025
Hole Location: 146 Middle Creek Road, Federal Logged By: RKG
Hole Position: 479639.0 m E 7079297.0 m N MGA2020 Zone 56 Checked By: ACD
Equipment Type and Model: 5.5t Excavator RL Surface: No survey
Excavation Dimensions: Datum: AHD Operator: Bebrok
Excavation Information Material Description and Observations
Relative Density
Classification
Shear
Penetration
Pocket
Consistency
Graphic Log
Samples Material Description Structure and
Penetrometer Vane
Condition
Recovery
Tests soil type: plasticity or particle characteristics, Additional
Moisture
UCS Test
Symbol
Method
secondary and minor components, colour Observations
Water
Remarks RL Depth (kPa) (kPa)
(m) (m)
100
200
300
400
500
50 100 150 200
CH Silty CLAY, high plasticity, dark brown to 0.00: SLOPEWASH
50
black, trace rootlets & subrounded gravel
F 70
CH Silty CLAY, high plasticity, pale brown grey, 0.25: RESIDUAL
BDS_0.3-0.8m mottled pale orange brown
100
0.5
120
St
becoming pale grey, mottled orange brown,
1.0 trace fine grained sand
230
TECTONIC 3.00.2 LIB.GLB Log 1 TECTONIC BOREHOLE 25050.GPJ <<DrawingFile>> 2/4/2025 16:32 10.02.00.04 Datgel Lab and In Situ Tool - DGD | Lib: Tectonic 3.00.2 2021-03-30 Prj: Tectonic 3.00.2 2021-03-30
w< 250
PL
Not Encountered
1.5
EX
VSt
CI Silty CLAY, medium plasticity, pale grey, 1.80: EXTREMELY
mottled pale yellow brown, trace fine grained WEATHERED MATERIAL
sand, with fine to coarse sized subangular 300
2.0 gravel, friable, rock texture perserved
2.5 2.50: PHYLLITE
PHYLLITE, highly weathered, pale grey,
stained yellow brown & orange brown, very
low strength
3.0
Hole Terminated at 3.20 m
Limit reach of machine
Method Penetration Water Samples and Tests Moisture Condition Consistency/Relative Density
N - Natural Exposure VE - Very Easy Level (Date) U## - Undisturbed Sample (## mm) D - Dry VS - Very Soft
X - Existing Excavation E - Easy DS - Disturbed Sample M - Moist S - Soft
BH - Backhoe Bucket Inflow BDS- Bulk Disturbed Sample W - Wet F - Firm
R - Ripper F - Firm VSt - Very Stiff
EX - Excavator H - Hard H - Hard
RH - Rock Hammer VH - Very hard VL - Very Loose
Plastic Limit
L - Loose
Classification Symbols < PL MD - Medium Dense
and Soil Descriptions = PL D - Dense
Based on Unified Soil < PL VD - Very Dense
Classification System Fr - Friable
Page 36
Test Pit No.
TP4
Page 1 of 1
Engineering Log - Test Pit Project No.: 25050
Client: Oceantobush Pastoral Trust Commenced: 13/3/2025
Project Name: Proposed Driveway & Residence Completed: 13/3/2025
Hole Location: 146 Middle Creek Road, Federal Logged By: RKG
Hole Position: 479512.0 m E 7079266.0 m N MGA2020 Zone 56 Checked By: ACD
Equipment Type and Model: 5.5t Excavator RL Surface: No survey
Excavation Dimensions: Datum: AHD Operator: Bebrok
Excavation Information Material Description and Observations
Relative Density
Classification
Shear
Penetration
Pocket
Consistency
Graphic Log
Samples Material Description Structure and
Penetrometer Vane
Condition
Recovery
Tests soil type: plasticity or particle characteristics, Additional
Moisture
UCS Test
Symbol
Method
secondary and minor components, colour Observations
Water
Remarks RL Depth (kPa) (kPa)
(m) (m)
100
200
300
400
500
50 100 150 200
Silty CLAY, (TOPSOIL) highly plasticity, dark 0.00: TOPSOIL
70
red brown to black, trace rootlets F
w<
Not Encountered
CH Silty CLAY, high plasticity, red brown, mottled PL 0.20: RESIDUAL
grey & orange brown, trace medium grained VSt
sand, fine to medium sized subangular gravel
BASALT, distinctly weathered, medium 0.40: BASALT
EX
0.5 strength, highly fractured, recovered as
subangular to angular coarse sized gravel &
cobbles 40-300mm size
Hole Terminated at 0.90 m
1.0 Very slow digging below 0.4m
TECTONIC 3.00.2 LIB.GLB Log 1 TECTONIC BOREHOLE 25050.GPJ <<DrawingFile>> 2/4/2025 16:32 10.02.00.04 Datgel Lab and In Situ Tool - DGD | Lib: Tectonic 3.00.2 2021-03-30 Prj: Tectonic 3.00.2 2021-03-30
1.5
2.0
2.5
3.0
Method Penetration Water Samples and Tests Moisture Condition Consistency/Relative Density
N - Natural Exposure VE - Very Easy Level (Date) U## - Undisturbed Sample (## mm) D - Dry VS - Very Soft
X - Existing Excavation E - Easy DS - Disturbed Sample M - Moist S - Soft
BH - Backhoe Bucket Inflow BDS- Bulk Disturbed Sample W - Wet F - Firm
R - Ripper F - Firm VSt - Very Stiff
EX - Excavator H - Hard H - Hard
RH - Rock Hammer VH - Very hard VL - Very Loose
Plastic Limit
L - Loose
Classification Symbols < PL MD - Medium Dense
and Soil Descriptions = PL D - Dense
Based on Unified Soil < PL VD - Very Dense
Classification System Fr - Friable
Page 37
Test Pit No.
TP5
Page 1 of 1
Engineering Log - Test Pit Project No.: 25050
Client: Oceantobush Pastoral Trust Commenced: 13/3/2025
Project Name: Proposed Driveway & Residence Completed: 13/3/2025
Hole Location: 146 Middle Creek Road, Federal Logged By: RKG
Hole Position: 479527.0 m E 7079288.0 m N MGA2020 Zone 56 Checked By: ACD
Equipment Type and Model: 5.5t Excavator RL Surface: No survey
Excavation Dimensions: Datum: AHD Operator: Bebrok
Excavation Information Material Description and Observations
Relative Density
Classification
Shear
Penetration
Pocket
Consistency
Graphic Log
Samples Material Description Structure and
Penetrometer Vane
Condition
Recovery
Tests soil type: plasticity or particle characteristics, Additional
Moisture
UCS Test
Symbol
Method
secondary and minor components, colour Observations
Water
Remarks RL Depth (kPa) (kPa)
(m) (m)
100
200
300
400
500
50 100 150 200
60 0.00: TOPSOIL
Silty CLAY, (TOPSOIL) high plasticity, dark
brown, trace rootlets & roots F 80
CH Silty CLAY, high plasticity, pale grey brown, 0.15: RESIDUAL
DS_0.2-0.5m trace fine grained sand & cobble sized
rounded cornerstone w<
U50_0.3-0.5m
Not Encountered
PL 180
VSt 190
0.5
EX
BASALT, distinctly weathered, medium 0.70: BASALT
strength, highly fractured, recovered as
subangular to angular coarse sized gravel &
cobbles 40-300mm size, ranging medium to
high strength particles
1.0
TECTONIC 3.00.2 LIB.GLB Log 1 TECTONIC BOREHOLE 25050.GPJ <<DrawingFile>> 2/4/2025 16:32 10.02.00.04 Datgel Lab and In Situ Tool - DGD | Lib: Tectonic 3.00.2 2021-03-30 Prj: Tectonic 3.00.2 2021-03-30
Hole Terminated at 1.20 m
Very slow digging below 0.7m
1.5
2.0
2.5
3.0
Method Penetration Water Samples and Tests Moisture Condition Consistency/Relative Density
N - Natural Exposure VE - Very Easy Level (Date) U## - Undisturbed Sample (## mm) D - Dry VS - Very Soft
X - Existing Excavation E - Easy DS - Disturbed Sample M - Moist S - Soft
BH - Backhoe Bucket Inflow BDS- Bulk Disturbed Sample W - Wet F - Firm
R - Ripper F - Firm VSt - Very Stiff
EX - Excavator H - Hard H - Hard
RH - Rock Hammer VH - Very hard VL - Very Loose
Plastic Limit
L - Loose
Classification Symbols < PL MD - Medium Dense
and Soil Descriptions = PL D - Dense
Based on Unified Soil < PL VD - Very Dense
Classification System Fr - Friable
Page 38
TERMS USED ON LOGS
DRILLING/EXCAVATION METHOD
AD* Auger Drilling RD Rotary Blade or Drag bit NQ Diamond Core - 47 mm
*V V-Bit RT Rotary Tri-cone bit NMLC Diamond Core - 52 mm
*T TC-Bit RA Rotary Air HQ Diamond Core - 63 mm
HA Hand Auger HMLC Diamond Core – 63mm
ADH Hollow Auger BH Tractor Mounted Backhoe
EX Tracked Hydraulic Excavator
WATER
GROUNDWATER NOT The observation of groundwater, whether present or not, was not possible due to drilling water,
OBSERVED surface seepage or cave in of the borehole/test pit.
GROUNDWATER NOT The borehole/test pit was dry soon after excavation. However, groundwater could be present in
ENCOUNTERED less permeable strata. Inflow may have been observed had the borehole/test pit been left open
for a longer period.
SAMPLING AND TESTING
SPT Standard Penetration Test to AS1289.6.3.1-2004
5,4,10 N=14 5,4,10 = Blows per 150mm. N = Blows per 300mm penetration following 150mm seating
30/65mm Where practical refusal occurs, the blows and penetration for that interval are reported
RW Penetration occurred under the rod weight only
HW Penetration occurred under the hammer and rod weight only
HB Hammer double bouncing on anvil
DS Disturbed sample
BDS Bulk disturbed sample
FV Field vane shear test expressed as uncorrected shear strength (sv = peak value, sr = residual value)
PP Pocket penetrometer test expressed as instrument reading in kPa
U50 Thin walled tube sample - number indicates nominal sample diameter in millimetres
DCP Dynamic cone penetration test
CPT Electronic cone penetration test
CPTu Electronic cone penetration test with pore pressure (u) measurement
Rev1
August 2024
Page 39
METHOD OF SOIL DESCRIPTION
USED ON LOGS
CLASSIFICATION AND INFERRED STRATIGRAPHY
Soil is classified and described in borehole and test pit logs using the preferred method given in AS1726 – 2017.
The material properties are assessed in the field by visual/tactile methods.
Particle Size Plasticity Properties
Major Sub Division Particle Size
Division
BOULDERS > 200 mm
COBBLES 63 to 200 mm
Coarse 19 to 63 mm
GRAVEL Medium 6.7 to 19 mm
Fine 2.36 to 6.7 mm
Coarse 0.6 to 2.36 mm
SAND Medium 0.21 to 0.6 mm
Fine 0.075 to 0.21
SILT 0.002 to 0.075
CLAY < 0.002 mm
NOTE: The U line is an approximate upper bound for most materials.
Data which plot above the U line may represent unusual/problem soil
behavior, or unreliable data and should be considered carefully.
MOISTURE CONDITION AS1726 - 2017
Coarse Grained Soils
Symbol Term Description
D Dry Sands and gravels are free flowing.
M Moist Soils are darker than in the dry condition & may feel cool. Sands and gravels tend to cohere.
W Wet Soils exude free water. Sands and gravels tend to cohere
Fine Grained Soils
Symbol Description
w < PL Moist, dry of plastic limit, (hard and friable or powdery)
w = PL Moist, near plastic limit, (soils can be moulded at a moisture content approximately equal to the plastic limit)
w > PL Moist, wet of plastic limit, (soils usually weakened and free water forms on hands when handling)
w = LL Wet, near liquid limit
w > LL Wet, wet of liquid limit
CONSISTENCY AND DENSITY AS1726 - 2017
Symbol Term Undrained Shear Symbol Term Density Index % SPT “N” #
Strength
VS Very Soft 0 to 12 kPa VL Very Loose Less than 15 0 to 4
S Soft 12 to 25 kPa L Loose 15 to 35 4 to 10
F Firm 25 to 50 kPa MD Medium Dense 35 to 65 10 to 30
St Stiff 50 to 100 kPa D Dense 65 to 85 30 to 50
VSt Very Stiff 100 to 200 kPa VD Very Dense Above 85 Above 50
H Hard Above 200 kPa
In the absence of test results, consistency and density may be assessed from correlations with the observed behaviour of
the material.
# SPT correlations are not stated in AS1726 – 2017, and may be subject to corrections for overburden pressure and
equipment type.
Rev3
November 2024
Page 40
METHOD OF ROCK DESCRIPTION
USED ON LOGS
CLASSIFICATION AND INFERRED STRATIGRAPHY
Rock is classified and described in borehole and test pit logs using the preferred method given in AS1726 – 2017.
The material properties are assessed in the field by visual/tactile methods.
STRENGTH
Point Load
Symbol Term Index, Is(50) Field Guide
(MPa)
VL Very 0.03 to 0.1 Material crumbles under firm blows with sharp end of pick; can be peeled
Low with knife; too hard to cut a triaxial sample by hand. Pieces up to 30 mm
can be broken by finger pressure.
L Low 0.1 to 0.3 Easily scored with a knife; indentations 1 mm to 3 mm show in the specimen
with firm blows of pick point; has dull sound under hammer. A piece of core
150 mm long by 50 mm diameter may be broken by hand. Sharp edges of core
may be friable and break during handling.
M Medium 0.3 to 1 Readily scored with a knife; a piece of core 150 mm long by 50 mm diameter
can be broken by hand with difficulty.
H High 1 to 3 A piece of core 150 mm long by 50 mm diameter cannot be broken by hand but
can be broken with pick with a single firm blow; rock rings under hammer.
VH Very 3 to 10 Hand specimen breaks with pick after more than one blow; rock rings under
High hammer.
EH Extremely >10 Specimen requires many blows with geological pick to break through intact
High material; rock rings under hammer.
Relationship between Is(50) and UCS (unconfined compressive strength) will vary with rock type and strength, and
should be determined on a site-specific basis. UCS is typically 10 to 30 x Is(50), but can be as low as 5.
ROCK MATERIAL WEATHERING
Symbol Term Field Guide
Soil developed on extremely weathered rock; the mass structure and
Residual
RS substance fabric are no longer evident; there is a large change in volume
Soil but the soil has not been significantly transported.
Extremely Rock is weathered to such an extent that it has soil properties - i.e. it either
EW
Weathered disintegrates or can be remoulded, in water.
Whole of rock is discoloured, usually by iron staining or bleaching to the
extent that the colour of the original rock is not recognizable. Rock strength
Highly
HW is significantly changed by weathering. Porosity may be increased by
Weathered
leaching, or may be decreased due to deposition of weathering products in
Distinctly
DW pores.
Weathered
Whole of rock is discoloured, usually by iron staining or bleaching to the
Moderately extent that the colour of the original rock is not recognizable; but shows little
MW
Weathered or no change of strength from fresh rock.
Slightly Rock is slightly discoloured but shows little or no change of strength relative
SW
Weathered to fresh rock.
FR Fresh Rock shows no sign of decomposition or staining.
ABBREVIATIONS FOR DEFECT TYPES AND DESCRIPTIONS
Defect Type Coating or Infilling Roughness
CS/CZ Crushed seam/zone (Fault) Ca Calcite Po Polished
DB Drilling break Clay Clay Sm Smooth
EW Extremely weathered seam Cn Clean Sl Slickensided
HB Handling break Co Coating ( > 1mm) Ro Rough
IS/IZ Infilled seam/zone Fe Iron oxide VRo Very rough
Op Open
J Joint
Qz Quartz
Pt Parting St Stain Planarity
SS/SZ Sheared seam/zone (Fault) Vn Veneer (<1mm) Cu Curved
Vn Vein X Carbonaceous Dis Discontinuous
Ir Irregular
Pl Planar
St Stepped
Un Undulating
Rev5
August 2024
Page 41
[Appendix subtitle (or delet e)]
Appendix B
Laboratory Test Certificates
Geotechnical Investigation & Slope Stability Assessment
9 April 2025 | 25050-001-Rev0 26
Page 42
Sunshine Coast Laboratory
11/1 Metier Linkway
Birtinya QLD 4575
Report No: CBR:S25SC-00167
California Bearing Ratio Test Report
Issue No: 1
Accredited for compliance with ISO/IEC 17025
Client: Tectonic Geotechnical Pty Ltd – Testing
Address: 924 David Low Way
Marcoola QLD 4564
Project: Middle Creek Rd, Federal
Project No.: 1098406
Accreditation Number: Approved Signatory: A. Collier
Order No.: CG Request No.: 12719 (Discipline Manager QLD)
TRN: 25050 Lot No.: Site Number: 25425 Date of Issue: 3/04/2025
THIS DOCUMENT SHALL NOT BE REPRODUCED EXCEPT IN FULL
Sample Details
Sample ID: S25SC-00167 Date Sampled: 13/03/2025
Sampled By: Client Sampling Method: As Received
Source: In-Situ Material: CLAY trace sand and gravel, brown, high
plasticity
Location: Middle Creek Rd, Federal
Location: TP3, 0.30 - 0.80m Date Tested: 1/04/2025
Load vs Penetration Test Results
AS 1289.6.1.1
CBR at 2.5mm (%): 1.5
Dry Density before Soaking (t/m³): 1.43
Density Ratio before Soaking (%): 95.5
Moisture Content before Soaking (%): 27.3
Moisture Ratio before Soaking (%): 97.5
Dry Density after Soaking (t/m³): 1.37
Density Ratio after Soaking (%): 91.5
Swell (%): 5.0
Moisture Content of Top 30mm (%): 39.8
Moisture Content of Remaining Depth (%): 31.0
Compaction Hammer Used: Standard
AS 1289.5.1.1
MDD (t/m³): 1.50
OMC (%): 28.0
Surcharge Mass (kg): 4.50
Period of Soaking (Days): 4
Retained on 19 mm Sieve (%): 0
CBR Moisture Content Method: AS 1289.2.1.1
Sample Curing Time (h): 239
Plasticity Determination Method: Visual/Tactile
Comments
These results apply to the sample as received.
Form No: 18986, Report No: CBR:S25SC-00167 © 2000-2025 QESTLab by SpectraQEST.com Page 1 of 1
Page 43
Sunshine Coast Laboratory
11/1 Metier Linkway
Birtinya QLD 4575
Report No: MDD:S25SC-00167
Maximum Dry Density Report
Issue No: 1
Accredited for compliance with ISO/IEC 17025
Client: Tectonic Geotechnical Pty Ltd – Testing
Address: 924 David Low Way
Marcoola QLD 4564
Project: Middle Creek Rd, Federal
Project No.: 1098406
Accreditation Number: Approved Signatory: A. Collier
Order No.: CG Request No.: 12719 (Discipline Manager QLD)
TRN: 25050 Lot No.: Site Number: 25425 Date of Issue: 3/04/2025
THIS DOCUMENT SHALL NOT BE REPRODUCED EXCEPT IN FULL
Sample Details
Location: Middle Creek Rd, Federal
Sample ID: S25SC-00167 Date Sampled: 13/03/2025
Sampling Method: As Received
Source: In-Situ Material: CLAY trace sand and gravel, brown, high
plasticity
Specification:
Location: TP3, 0.30 - 0.80m
Date Tested: 25/03/2025
Dry Density - Moisture Content Relationship Test Results
AS 1289.5.1.1
Standard MDD (t/m³): 1.50
Standard OMC (%): 28.0
Retained Sieve (mm): 19.0
Oversize Material (%): 0
Curing Time (h): 168
LL Method: Visual / Tactile
Comments
These results apply to the sample as received.
Form No: 18995, Report No: MDD:S25SC-00167 © 2000-2025 QESTLab by SpectraQEST.com Page 1 of 1
Page 44
Head Office Queensland Office
25 Metcalf Street Unit 11/1 Metier Linkway
DANDENONG SOUTH BIRTINYA
VIC 3175 QLD 4575
Ph: +61 3 8796 7900 Ph: +61 7 5390 1100
SHRINK SWELL TEST REPORT
Customer: Tectonic Geotechnical Pty Ltd Report Number: SS-S25SC-00166
Customer Address: 924 David Low Way, Marcoola QLD Report Date: 3/04/2025
Project: Middle Creek Road, Federal CG Job No: 1098406
Location: Middle Creek Road, Federal Test Method: AS1289.7.1.1
Customer Order No.: 25050 Page: 1 of 1
Testing performed and reported at our Sunshine Coast Laboratory (Site No. 25425)
Sample No.: S25SC-00166
ID No: -
Lot No: -
Date Sampled: 13/03/2025
Material Source: In-Situ
Material Description: CLAY trace sand, dark brown, high plasticity
Sampling Procedure: As Received
Sample Type: U50
Sample Location: TP5
0.30 - 0.50m
SHRINK TEST AS1289 7.1.1 Cl 5.2
Length of Specimen (mm) 68.96
Mass of Specimen (g) 194.2
Mass of Oven dried Specimen (g) 134.9
Initial Moisture Content (w3) % AS1289 2.1.1 44.0
Extent of Soil Cracking Minor
Extent of Soil Crumbling Nil
Estimated Inert Inclusions (%) 14.2
Shrinkage % 12.3
SWELL TEST AS1289 7.1.1 Cl 5.1
Vertical Surcharge Pressure During Swelling (kPa) 25
Height of Specimen (mm) 20
Initial Moisture Content (w1) % AS1289 2.1.1 44.6
Final Moisture Content (w2) % AS1289 2.1.1 50.0
Swell % 0.2
SHRINK SWELL INDEX (Iss) % 6.9
Remarks:
APPROVED SIGNATORY
Accredited for compliance with ISO/IEC 17025
Form No.: CG.332.008
Corporate Accreditation No. 12719
This report shall not be reproduced expect in full. Reported Issue Date: 02/08/2024
results are related only to the item(s) tested.
A Collier
Page 45
[Appendix subtitle (or delet e)] Appendix C AGS 2007 Practice Note Guidelines for Landslide Risk Management & Qualitative Terminology for Use in Assessing Risk to Property Geotechnical Investigation & Slope Stability Assessment 9 April 2025 | 25050-001-Rev0 27
Page 46
PRACTICE NOTE GUIDELINES FOR LANDSLIDE RISK MANAGEMENT 2007
APPENDIX C: LANDSLIDE RISK ASSESSMENT
QUALITATIVE TERMINOLOGY FOR USE IN ASSESSING RISK TO PROPERTY
QUALITATIVE MEASURES OF LIKELIHOOD
Approximate Annual Probability
Implied Indicative Landslide
Description Descriptor Level
Indicative Notional Recurrence Interval
Value Boundary
10-1 5x10-2
10 years The event is expected to occur over the design life. ALMOST CERTAIN A
20 years The event will probably occur under adverse conditions over the
-2
10 100 years
design life.
LIKELY B
-3
-3 5x10 200 years
10 1000 years The event could occur under adverse conditions over the design life. POSSIBLE C
5x10-4 2000 years
The event might occur under very adverse circumstances over the
10-4 10,000 years
design life.
UNLIKELY D
-5 5x10-5 20,000 years
10 The event is conceivable but only under exceptional circumstances
100,000 years RARE E
over the design life.
-6 5x10-6 200,000 years
10 1,000,000 years The event is inconceivable or fanciful over the design life. BARELY CREDIBLE F
Note: (1) The table should be used from left to right; use Approximate Annual Probability or Description to assign Descriptor, not vice versa.
QUALITATIVE MEASURES OF CONSEQUENCES TO PROPERTY
Approximate Cost of Damage
Description Descriptor Level
Indicative Notional
Value Boundary
Structure(s) completely destroyed and/or large scale damage requiring major engineering works for
200% CATASTROPHIC 1
stabilisation. Could cause at least one adjacent property major consequence damage.
100%
Extensive damage to most of structure, and/or extending beyond site boundaries requiring significant
60% MAJOR 2
stabilisation works. Could cause at least one adjacent property medium consequence damage.
40%
Moderate damage to some of structure, and/or significant part of site requiring large stabilisation works.
20% MEDIUM 3
Could cause at least one adjacent property minor consequence damage.
10%
5% 1% Limited damage to part of structure, and/or part of site requiring some reinstatement stabilisation works. MINOR 4
Little damage. (Note for high probability event (Almost Certain), this category may be subdivided at a
0.5% INSIGNIFICANT 5
notional boundary of 0.1%. See Risk Matrix.)
Notes: (2) The Approximate Cost of Damage is expressed as a percentage of market value, being the cost of the improved value of the unaffected property which includes the land plus the
unaffected structures.
(3) The Approximate Cost is to be an estimate of the direct cost of the damage, such as the cost of reinstatement of the damaged portion of the property (land plus structures), stabilisation
works required to render the site to tolerable risk level for the landslide which has occurred and professional design fees, and consequential costs such as legal fees, temporary
accommodation. It does not include additional stabilisation works to address other landslides which may affect the property.
(4) The table should be used from left to right; use Approximate Cost of Damage or Description to assign Descriptor, not vice versa
Australian Geomechanics Vol 42 No 1 March 2007
68039 Landslide Risk Management Issued 10/7/07
Page 47
PRACTICE NOTE GUIDELINES FOR LANDSLIDE RISK MANAGEMENT 2007
APPENDIX C: – QUALITATIVE TERMINOLOGY FOR USE IN ASSESSING RISK TO PROPERTY (CONTINUED)
QUALITATIVE RISK ANALYSIS MATRIX – LEVEL OF RISK TO PROPERTY
LIKELIHOOD CONSEQUENCES TO PROPERTY (With Indicative Approximate Cost of Damage)
Indicative Value of 1: CATASTROPHIC 2: MAJOR 3: MEDIUM 4: MINOR 5:
Approximate Annual 200% 60% 20% 5% INSIGNIFICANT
Probability 0.5%
A – ALMOST CERTAIN 10-1 VH VH VH H M or L (5)
-2
B - LIKELY 10 VH VH H M L
C - POSSIBLE 10-3 VH H M M VL
D - UNLIKELY 10-4 H M L L VL
-5
E - RARE 10 M L L VL VL
-6
F - BARELY CREDIBLE 10 L VL VL VL VL
Notes: (5) For Cell A5, may be subdivided such that a consequence of less than 0.1% is Low Risk.
(6) When considering a risk assessment it must be clearly stated whether it is for existing conditions or with risk control measures which may not be implemented at the current
time.
RISK LEVEL IMPLICATIONS
Risk Level Example Implications (7)
Unacceptable without treatment. Extensive detailed investigation and research, planning and implementation of treatment
VH VERY HIGH RISK options essential to reduce risk to Low; may be too expensive and not practical. Work likely to cost more than value of the
property.
Unacceptable without treatment. Detailed investigation, planning and implementation of treatment options required to reduce
H HIGH RISK
risk to Low. Work would cost a substantial sum in relation to the value of the property.
May be tolerated in certain circumstances (subject to regulator’s approval) but requires investigation, planning and
M MODERATE RISK implementation of treatment options to reduce the risk to Low. Treatment options to reduce to Low risk should be
implemented as soon as practicable.
Usually acceptable to regulators. Where treatment has been required to reduce the risk to this level, ongoing maintenance is
L LOW RISK
required.
Acceptable. Manage by normal slope maintenance procedures.
VL VERY LOW RISK
Note: (7) The implications for a particular situation are to be determined by all parties to the risk assessment and may depend on the nature of the property at risk; these are only
given as a general guide.
Australian Geomechanics Vol 42 No 1 March 2007
68039 Landslide Risk Management Issued 10/7/07
Page 48
PRACTICE NOTE GUIDELINES FOR LANDSLIDE RISK MANAGEMENT 2007
APPENDIX G - SOME GUIDELINES FOR HILLSIDE CONSTRUCTION
GOOD ENGINEERING PRACTICE POOR ENGINEERING PRACTICE
ADVICE
GEOTECHNICAL Obtain advice from a qualified, experienced geotechnical practitioner at early Prepare detailed plan and start site works before
ASSESSMENT stage of planning and before site works. geotechnical advice.
PLANNING
SITE PLANNING Having obtained geotechnical advice, plan the development with the risk Plan development without regard for the Risk.
arising from the identified hazards and consequences in mind.
DESIGN AND CONSTRUCTION
Use flexible structures which incorporate properly designed brickwork, timber Floor plans which require extensive cutting and
or steel frames, timber or panel cladding. filling.
HOUSE DESIGN
Consider use of split levels. Movement intolerant structures.
Use decks for recreational areas where appropriate.
SITE CLEARING Retain natural vegetation wherever practicable. Indiscriminately clear the site.
ACCESS & Satisfy requirements below for cuts, fills, retaining walls and drainage. Excavate and fill for site access before
DRIVEWAYS Council specifications for grades may need to be modified. geotechnical advice.
Driveways and parking areas may need to be fully supported on piers.
EARTHWORKS Retain natural contours wherever possible. Indiscriminatory bulk earthworks.
Minimise depth. Large scale cuts and benching.
CUTS Support with engineered retaining walls or batter to appropriate slope. Unsupported cuts.
Provide drainage measures and erosion control. Ignore drainage requirements
Minimise height. Loose or poorly compacted fill, which if it fails,
Strip vegetation and topsoil and key into natural slopes prior to filling. may flow a considerable distance including
Use clean fill materials and compact to engineering standards. onto property below.
FILLS Batter to appropriate slope or support with engineered retaining wall. Block natural drainage lines.
Provide surface drainage and appropriate subsurface drainage. Fill over existing vegetation and topsoil.
Include stumps, trees, vegetation, topsoil,
boulders, building rubble etc in fill.
ROCK OUTCROPS Remove or stabilise boulders which may have unacceptable risk. Disturb or undercut detached blocks or
& BOULDERS Support rock faces where necessary. boulders.
Engineer design to resist applied soil and water forces. Construct a structurally inadequate wall such as
Found on rock where practicable. sandstone flagging, brick or unreinforced
RETAINING
Provide subsurface drainage within wall backfill and surface drainage on slope blockwork.
WALLS
above. Lack of subsurface drains and weepholes.
Construct wall as soon as possible after cut/fill operation.
Found within rock where practicable. Found on topsoil, loose fill, detached boulders
Use rows of piers or strip footings oriented up and down slope. or undercut cliffs.
FOOTINGS
Design for lateral creep pressures if necessary.
Backfill footing excavations to exclude ingress of surface water.
Engineer designed.
Support on piers to rock where practicable.
SWIMMING POOLS Provide with under-drainage and gravity drain outlet where practicable.
Design for high soil pressures which may develop on uphill side whilst there
may be little or no lateral support on downhill side.
DRAINAGE
Provide at tops of cut and fill slopes. Discharge at top of fills and cuts.
Discharge to street drainage or natural water courses. Allow water to pond on bench areas.
SURFACE Provide general falls to prevent blockage by siltation and incorporate silt traps.
Line to minimise infiltration and make flexible where possible.
Special structures to dissipate energy at changes of slope and/or direction.
Provide filter around subsurface drain. Discharge roof runoff into absorption trenches.
Provide drain behind retaining walls.
SUBSURFACE
Use flexible pipelines with access for maintenance.
Prevent inflow of surface water.
Usually requires pump-out or mains sewer systems; absorption trenches may Discharge sullage directly onto and into slopes.
SEPTIC &
be possible in some areas if risk is acceptable. Use absorption trenches without consideration
SULLAGE
Storage tanks should be water-tight and adequately founded. of landslide risk.
EROSION Control erosion as this may lead to instability. Failure to observe earthworks and drainage
CONTROL & Revegetate cleared area. recommendations when landscaping.
LANDSCAPING
DRAWINGS AND SITE VISITS DURING CONSTRUCTION
DRAWINGS Building Application drawings should be viewed by geotechnical consultant
SITE VISITS Site Visits by consultant may be appropriate during construction/
INSPECTION AND MAINTENANCE BY OWNER
OWNER’S Clean drainage systems; repair broken joints in drains and leaks in supply
RESPONSIBILITY pipes.
Where structural distress is evident see advice.
If seepage observed, determine causes or seek advice on consequences.
Australian Geomechanics Vol 42 No 1 March 2007 113
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PRACTICE NOTE GUIDELINES FOR LANDSLIDE RISK MANAGEMENT 2007 114 Australian Geomechanics Vol 42 No 1 March 2007
Page 50
[Appendix subtitle (or delet e)]
Appendix D
Limitations
Geotechnical Investigation & Slope Stability Assessment
9 April 2025 | 25050-001-Rev0 28
Page 51
Limitations This document has been prepared for the purpose outlined in Tectonic’s proposal and no responsibility is accepted for the use of this document, in whole or in part, for any other purpose. The scope of Tectonic’s Services are as described in Tectonic’s proposal, and are subject to restrictions and limitations. Tectonic did not perform a complete assessment of all possible conditions or circumstances that may exist at the site referenced in the report. If a service is not expressly indicated, do not assume it has been provided. If a matter is not addressed, do not assume that any determination has been made by Tectonic in regards to it. Conditions may exist which were undetectable given that economic and time constraints limit the practical extent of geotechnical investigation. Variations in conditions may occur between investigation locations, and there may be special conditions pertaining to the site which have not been revealed by the investigation and which have not therefore been taken into account in the document. Where variations exist on site, additional studies and actions may be required. Tectonic’s opinions are based upon information that existed at the time that the work was performed. The passage of time, man-made or natural events, may alter the site conditions. It is understood that the Services undertaken allowed Tectonic to form an opinion of the actual conditions of the site at the time the site was visited and cannot be used to assess the effect of any subsequent changes in the quality of the site, or its surroundings, or any laws or regulations. Any assessments made in the preparation of this document are based on the conditions indicated from published sources and the findings of the investigation described. Actual subsurface conditions may differ from those indicated in the document (e.g. between boreholes or test pits). No warranty is included, either express or implied, that the actual conditions will conform exactly to the assessments contained in this document. Where data supplied by the client or other external sources, including previous site investigation data, have been used, it has been assumed that the information is correct unless otherwise stated. No responsibility is accepted by Tectonic for incomplete or inaccurate data supplied by others. This document is provided for the sole use by the Client and its professional advisers. No responsibility whatsoever for the contents of this document will be accepted to any person other than the Client. Any use which a third party makes of this document, or any reliance on or decisions to be made based on it, is the responsibility of such third parties. Tectonic accepts no responsibility for damages, if any, suffered by any third party as a result of decisions made or actions based on this document. Limitations August 2024 | Rev2
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PO Box 899 tectonicgeo.com.au [email protected]
Buderim
Geotechnical QLD 4555
Investigation & Slope Stability Assessment
9 April 2025 | 25050-001-Rev0 29
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APPENDIX C Response to Noosa Plan 2020 Codes 2505 Rev. 1 OPW052025 May 2025
Page 54
8.2.2 Biodiversity, Waterways and Wetlands Overlay Code
Table 8.2.2.3 - Criteria for assessable development
Performance outcomes Acceptable outcomes Response
Ecologically important areas
PO1 AO1.1 The proposed driveway follows an existing track located
Development is sited and designed to protect the physical and Ecologically important areas are conserved or improved to ensure through the allotment with minimal to no clearing.
ecological integrity and biodiversity of ecologically important areas their ongoing contribution to the natural resources and biological Performance Outcome PO1 and Acceptable Outcomes
AO1.1, AO1.2 and AO1.3 is met. AO1.4 is not applicable
through protection of: diversity of Noosa Shire.
(a) existing habitat areas and ecological linkages; and
AND
(b) existing riparian vegetation, waterways and wetland habitat
values.
AO1.2
Buildings, structures and associated works are located within
existing cleared areas or areas of lowest ecological value.
AND
AO1.3
Where constructing a dwelling house or community residence,
buildings and associated structures are not located on land
identified as an area of biodiversity significance on a Biodiversity,
Waterways and Wetlands Overlay Map.
or
Clearing vegetation (other than for a driveway access) does not
extend beyond—
(a) 30 metres of a habitable building or 10 metres of a class
10 structure on lots greater than 10 hectares; or
(b) 10 metres of a habitable building or class 10 structure on
lots 10 hectares or less but more than 3,000m2; or
(c) 3 metres of a habitable building or class 10 structure on
lots 3,000m2 or less.
AND
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AO1.4
Clearing of vegetation for a boundary fence does not extend
beyond 5 metres either side of the fence.
Reconfiguring a lot Table 8.2.2.3 - Criteria for assessable development (part)
Performance outcomes Acceptable outcomes Response
Reconfiguring a lot
PO2 AO2 Not applicable as no new allotments form part of this
New lots are only created if they maintain ecological linkages and Where clearing vegetation for the purpose of Reconfiguring a Lot: application noting minimal clearing works are required.
minimise the clearing of vegetation. (a) new boundaries to lots do not transect and fragment
existing native vegetation;
(b) new lots are created to allow for suitable building
envelopes for future buildings and works to be located
within existing cleared areas or areas of low ecological
value;
(c) building envelopes are designated for each lot; and
(d) ecological linkages and ecologically important areas are
secured by environmental covenant or transferred to public
ownership or through gazettal of a nature reserve.
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Management of impacts Table 8.2.2.3 - Criteria for assessable development (part)
Performance outcomes Acceptable outcomes Response
Management of impacts
PO3 AO3.1 The proposed driveway follows an existing track located
Development is designed and sited to manage adverse impacts Where clearing of vegetation cannot be practicably avoided, the through the allotment with minimal to no clearing or adverse
on ecologically important areas by: development: impacts on ecologically important areas.
Performance Outcome PO3 and Acceptable Outcomes
(a) minimising the total footprint within which all activities, (a) ensures the design and siting limits the loss of vegetation
AO3.1 and AO3.2 can be met.
buildings, structures driveways and other works are to the smallest extent possible;
contained; protects and retains ecological values and ecosystem
(b)
(b) locating development in existing cleared areas or areas of processes to the greatest extent possible within and
low ecological value over other areas to the greatest extent adjacent to the site;
possible; and provides measures to allow for safe movement of fauna
(c)
(c) incorporating siting and design measures to protect and through the site; and
retain ecological values and ecosystem processes within (d) provides suitable habitat replacement and replanting in
or adjacent to the development site; and accordance with PSP3 Ecological Assessment Guidelines.
(d) where adverse impacts have been minimised, any AO3.2
residual impacts on ecological values are compensated Habitat trees, recruitment habitat trees, and roosting, breeding
for through suitable habitat replacement and replanting on and feeding areas are protected for native fauna habitat.
site in the first instance or in a way that results in a net
gain and enhancement of the overall habitat values of
Noosa Shire.
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Performance outcomes Acceptable outcomes Response
Management of impacts
PO4 AO4.1 Best practice construction methods for the driveway works
Development provides for effective measures during construction Vegetation is protected from disturbance or damage from will be implemented.
The proposal meets the requirements of AO4.1, AO4.2,
and operation to protect ecological values including: construction and operation activities by: AO4.3 and AO4.4.
(a) avoiding disturbance to or clearing of vegetation in and (a) clearly marking trees to be retained with flagging tape; Performance Outcome PO4 can be met.
within the vicinity of the site; installing protective fencing around the dripline of the
(b)
(b) managing habitat disturbance and physical harm to fauna vegetation and avoid filling and excavating in these fenced
from noise, vibration, dust, light, dewatering or excavating; areas;
and ensuring stockpiling, storage and vehicle parking occurs
(c)
(c) avoiding clearing in areas where erosion or slippage could outside the identified vegetation areas; and
occur. using low impact construction techniques around
(d)
vegetation.
AO4.2
Vegetation which is capable of forming or contributing to a buffer
between different land uses or a buffer against pollution, light
spillage or noise is retained.
AO4.3
Lighting associated with development:
(a) does not contribute an unacceptable level of illuminance
(greater than 1 lux) for light sensitive species within or at
the boundary of an ecologically important area; and
(b) does not contribute to an unacceptable level of illuminance
on landward horizons along coastal areas and known
marine turtle nesting beaches.
AO4.4
Clearing of vegetation does not involve clearing that may cause or
contribute to hillslope erosion, bank erosion, or slippage.
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Connectivity Table 8.2.2.3 - Criteria for assessable development (part)
Performance outcomes Acceptable outcomes Response
Connectivity
PO5 AO5 The proposed driveway follows an existing track located
Development is designed and operated to maintain and enhance Development is designed and operated to maintain ecological through the allotment with minimal to no clearing or adverse
connectivity between and across ecologically important areas and linkages and maximise opportunity for connectivity and the impacts on ecologically important areas.
connecting habitat and support unimpeded and safe movement of movement of fauna by: Performance Outcome PO5 and Acceptable Outcome AO5
terrestrial and aquatic fauna. can be met.
(a) ensuring protection of wildlife refuges;
(b) maintaining vegetation in patches of the greatest possible
size and within the smallest possible edge-to-area ratio;
(c) enhancing connectivity through planting and rehabilitation
works, including across property boundaries, to areas of
national park, state forest or reserve;
(d) avoiding the creation of physical barriers and safety
hazards (such as roads, pedestrian access and instream
structures) along and within the ecological linkage;
(e) providing mitigation measures such as wildlife movement
infrastructure, fauna exclusion and directional fencing,
underpasses/overpasses and traffic calming devices,
signage and lighting; and
(f) where offsets are necessary, delivering offsets that support
and enhance ecological linkages.
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Waterways and wetlands Table 8.2.2.3 - Criteria for assessable development (part)
Performance outcomes Response
Waterways and wetlands
PO6 AO6.1 Not applicable as driveway is not located within waterways,
The biodiversity and ecosystem values of waterways, wetlands Development and clearing of vegetation does not occur within: wetlands or adjacent riparian zones.
and adjacent riparian zones are protected by: (a) a riparian buffer area;
(a) avoiding any new development in a riparian buffer area and (b) a wetland area; or
wetland area;
(c) 10 metres either side of the centre line of other waterways
(b) retaining aquatic and terrestrial habitat in riparian zones; identified on a Biodiversity, Waterways and Wetlands
(c) maintaining and enhancing wildlife corridors and Overlay Map.
connectivity along watercourses and drainage lines for
native fauna movement; AO6.2
(d) avoiding edge effects and damage from adjacent land Development provides for the rehabilitation of land within:
uses; (a) a riparian buffer area;
(e) maintaining stream integrity and bank stability by (b) a wetland area; and
minimising bank erosion and slumping;
(c) 10 metres either side of the centre line of any other
(f) maintaining water quality through filtering sediments, waterway identified on a Biodiversity, Waterways and
nutrients and other pollutants; and Wetlands Overlay Map.
(g) removing pest species and replacing them with local native
species. AO6.3
Recreational facilities (eg. playgrounds, pergolas, barbeques) are
setback a minimum of 10 metres from the top of the bank of a
waterway.
Editor’s Note—Setbacks to waterways for certain uses and works
are also specified in the relevant codes.
Editor's Note—Wetland areas are identified on the Queensland
Wetland Program mapping
Editor's Note—Any clearing of vegetation also needs to meet the
outcomes of the Earthworks Code and the Water Quality and
Drainage Code.
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Performance outcomes Response
Waterways and wetlands
PO7 Not applicable as not within 400m of Lake Macdonald.
Vegetation within 400 metres of the full ponded water within Lake No acceptable outcome provided.
Macdonald is retained.
PO8 AO8.1 Not applicable as no development is proposed adjacent to a
Development on land adjacent to a waterway or wetland Development adjacent to a waterway or wetland provides that: waterway or wetland.
maintains appropriate extent of public access to waterways and (a) no new lots directly back onto a riparian buffer area; and
wetlands and minimises edge effects.
(b) new public roads are located between a riparian buffer area
or riparian zone and the proposed development area.
Water hydrology Table 8.2.2.3. - Criteria for assessable development (part)
Performance outcomes Acceptable outcomes Response
Surface and ground water hydrology
PO9 AO9.1 The proposed driveway follows an existing track located
Development ensures that the natural surface water and ground Development does not impact on the natural surface water or through the allotment.
water hydrologic regimes of waterways, wetlands and groundwater hydrologic regimes and this is facilitated by: Performance Outcome PO9 and Acceptable Outcome
hydrologically-sensitive plant communities are not adversely AO9.1 can be met.
(a) avoiding or minimising channelization, redirection or
impacted. interruption of flow;
(b) avoiding groundwater extraction;
Editor's Note—Groundwater dependent ecosystems are identified
on Queensland Government Wetland Info mapping. (c) maintaining groundwater recharge and discharge
processes;
(d) maintaining natural groundwater fluctuations;
(e) avoiding causing ingress of saline water into freshwater
aquifers of wetlands; and
(f) avoiding contaminants entering groundwater (e.g. from
runoff, effluent disposal).
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Rehabilitation of ecologically important areas Table 8.2.2.3 - Criteria for assessable development (part)
Performance outcomes Acceptable outcomes Response
Rehabilitation of ecologically important areas
PO10 AO10.1 Not applicable as no new development is proposed. The
Development provides for ecologically important areas to be Landscaping and rehabilitation complements and supports proposed driveway follows an existing track located through
restored and enhanced through: ecologically important areas by: the allotment.
(a) designing landscaped areas to complement and enhance (a) utilising local native species;
existing vegetation and ecological linkages; utilising suitable plant species identified in PSP2
(b)
(b) removing species likely to displace native flora species or Landscaping;
degrade fauna habitat; restoring degraded ecosystems to achieve a functional
(c)
(c) replanting and rehabilitating degraded habitat; ecosystem state that requires minimal human intervention;
(d) replacing any vegetation removed with suitable local native (d) replicating adjacent remnant habitats of the same type,
species; including the understorey vegetation;
(e) providing for fauna habitat; and (e) creating or enhancing linkages between existing habitats;
(f) avoiding the planting of pest plant species. (f) avoiding the use of pest plant species listed in PSP2 -
Landscaping;
(g) planting riparian zones to filter stormwater run-off, stabilise
soil and provide for wildlife habitat; and
(h) providing ground and arboreal structures for fauna, which
may include ground depressions, rocks, hollows, nesting
boxes and in-stream habitat.
AO10.2
Vegetation cleared is replaced with:
(a) plantings of equivalent area that replicate the floristic
structure of the vegetation removed; or
(b) where this is not possible due to the characteristics of the
site and the development, plantings twice the number of the
removed trees and plants.
(e) Editor’s Note — Revegetation and rehabilitation works
are to be carried out in accordance with an approved
Revegetation and Rehabilitation Management Plan, as
referred to in PSP3 Ecological assessment guidelines
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Koala habitat protection and enhancement Table 8.2.2.3 - Criteria for assessable development (part)
Performance outcomes Acceptable outcomes Response
Koala habitat protection and enhancement
PO11 AO11.1 Not applicable as the proposed driveway follows an existing
Development is designed, constructed and operated to— Development design complies with the Koala-sensitive Design track located through the allotment.
(a) protect and enhance koalas and koala habitat and avoid Guideline: A guide to koala sensitive design measures for
adverse impacts; planning and development activities.
(b) provide measures to assist the survival of koala
AO11.2
populations in the area to mitigate any potential threats or
Development incorporates revegetation and landscaping that
risk to koalas; and
provides food, shelter and movement opportunities for koalas.
(c) provide for safe and appropriate koala movement across
the landscape. AO11.3
Development is designed to maximise and enhance connectivity
Editor's Note—Koala habitat mapping is in Schedule 2 Mapping. between koala habitat trees and ensure safe koala movement.
Editor's Note—The Planning Regulation 2017, schedule 10 states AO11.4
that development that interferes with koala habitat, in an area that During construction, measures are incorporated to not increase
is both a koala priority area and a koala habitat area, is prohibited the risk of death or injury to koalas, by including safe koala
development (subject to the exceptions stated in schedule 10 of movement measures, as defined in the Planning Regulation
the Planning Regulation 2017). 2017.
Editor's Note - These performance outcomes and acceptable
outcomes apply to:
(a) development on land in a koala priority area, where the
development does not interfere with koala habitat and
where the benchmarks are additional to and not
inconsistent with, the assessment benchmarks stated in
schedule 11, part 2 of the Planning Regulations 2017; and
(b) development on land outside the koala priority area, where
the development does not interfere with koala habitat in
koala habitat areas.
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Bushfire management Table 8.2.2.3 - Criteria for assessable development (part)
Performance outcomes Acceptable outcomes Response
Bushfire management
PO12 No acceptable outcome provided Not applicable as the proposed driveway follows an
Bushfire management measures are adopted based on existing track located through the allotment.
ecological principles, which:
(a) maintain and enhance biodiversity;
(b) minimise threat of fire to the natural environment, as well
as life and property; and
(c) provide for effective use and maintenance of buildings and
structures.
Editor's note—The performance outcome applies to properties in
bushfire hazard areas and only where clearing is reasonably
necessary for the control of bushfire risk to a building or
structure. Bushfire hazard areas are shown on Bushfire Hazard
Overlay maps in Schedule 2.
Scenic amenity Table 8.2.2.3 - Criteria for assessable development (part)
Performance outcomes Acceptable outcomes Response
Scenic amenity
PO13 AO13.1 The proposed driveway follows an existing track located
The scenic amenity and vegetated character of the landscape Vegetation is retained: through the allotment with minimal to no clearing.
is protected by retaining vegetation: (a) on and within 30 metres of prominent ridgelines and on Performance Outcome PO13 and Acceptable Outcome
AO13.1 can be met.
(a) along and around watercourses and drainage lines; sloping sites;
(b) on steep slopes and ridgelines; (b) in gullies;
(c) along the major road network; and (c) along watercourses and drainage lines;
(d) that forms coastal vistas to and from beaches. (d) within 10 metres of the major road network; and
(e) along the front coastal dune system.
The text continues on page 64.