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Hydrogeological and Geotechnical Investigation Inkpen Road Waste Management Facility Shire of Northam
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Assets | Engineering | Environment | Noise | Spatial | Waste
Hydrogeological and Geotechnical Investigation
Inkpen Road Waste Management Facility
Prepared for Shire of Northam
September 2017
Project Number: TW17035
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DOCUMENT CONTROL
Version Description Date Author Reviewer
0a Internal Review 12/09/2017 JS FD
1a Released to Client 20/09/2017 JS FD
Approval for Release
Name Position File Reference
Fraser Daly Senior Geo-Environmental Consultant TW17035-Inkpen Road Site Investigation_1a
Signature
Copyright of this document or any part of this document remains with Talis Consultants Pty Ltd and cannot be used,
transferred or reproduced in any manner or form without prior written consent from Talis Consultants Pty Ltd.
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Table of Contents 1 Introduction ............................................................................................................................................ 1
1.1 Objectives .............................................................................................................................................. 1
1.2 Scope of Work ....................................................................................................................................... 1
2 Background ............................................................................................................................................. 2
2.1 Location ................................................................................................................................................. 2
2.2 Zoning and Surrounding Land Use ........................................................................................................ 2
2.3 Environmental Attributes ...................................................................................................................... 2
2.3.1 Climate ................................................................................................................................... 2
2.3.2 Site Conditions ....................................................................................................................... 3
2.3.3 Topography ............................................................................................................................ 3
2.4 Geology ................................................................................................................................................. 3
2.4.1 Quaternary Geology ............................................................................................................... 3
2.4.2 Archean geology .................................................................................................................... 3
2.4.3 Structural Geology ................................................................................................................. 3
2.5 Hydrogeology ........................................................................................................................................ 3
2.5.1 Hydrogeology ......................................................................................................................... 3
2.5.2 Groundwater Use ................................................................................................................... 3
2.5.3 Hydrology ............................................................................................................................... 4
3 Project Methodology ............................................................................................................................... 5
3.1 Intrusive Investigation ........................................................................................................................... 5
3.2 Drilling Techniques ................................................................................................................................ 5
3.2.1 Soil Testing ............................................................................................................................. 5
4 Field Observations ................................................................................................................................... 6
4.1 Geology ................................................................................................................................................. 6
4.2 Groundwater Well Construction Details ............................................................................................... 7
4.3 Survey Data ........................................................................................................................................... 8
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4.4 Groundwater Depth and Flow Direction ............................................................................................... 8
5 Geotechnical Laboratory Results and Assessment ................................................................................... 9
5.1 Soil Index Testing .................................................................................................................................. 9
5.2 Permeability .......................................................................................................................................... 9
6 Conceptual Site Model .......................................................................................................................... 10
6.1 Contamination Source ........................................................................................................................ 10
6.2 Contaminants of Potential Concern .................................................................................................... 10
6.3 Receptors ............................................................................................................................................ 10
6.4 Transportation Mechanisms ............................................................................................................... 10
6.5 Exposure Pathways and Qualitative Risk Assessment ........................................................................ 11
7 Discussion ............................................................................................................................................. 13
8 Conclusions and Recommendations ...................................................................................................... 14
References ..................................................................................................................................................... 15
Figures ........................................................................................................................................................... 16
Tables Table 4-1: Groundwater Well Construction Details
Table 4-2: Groundwater Well Survey Details
Table 5-1: Soil Index
Table 5-2 Falling Head Test Permeability
Table 6-1 Risk Assessment
Figures Figure 1: Locality
Figure 2: Site Aerial
Figure 3: Zoning
Figure 4: Topography
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Figure 5: Quaternary Geology
Figure 6: Archean Geology
Figure 7: Hydrogeology
Figure 8: Hydrology
Figure 9: Bore Locations
Appendices : Bore Logs
: Photographs
: Laboratory Certificates
: Survey Data
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1 Introduction
Talis Consultants Pty Ltd (Talis) was engaged by the Shire of Northam (the Shire) to undertake a Works Approval
and Licence Application for a Category 64 Class II Putrescible Landfill and a Category 62 Solid Waste Depot at its
Inkpen Road Waste Management Facility. As part of the Works Approval, a site investigation targeting the
hydrogeological regime and the geotechnical properties of the underlying soils was undertaken to support the
future development of the Site, while allowing for the assessment of potential impacts to groundwater.
This report forms part of the overall works approval document (TW17035 – Northam EAMP.1a-Environmental
Assessment Management Plan, Inkpen Road Waste Management Facility, Talis, 2017), and should be read in
conjunction with this documentation.
1.1 Objectives
The objective of the Site investigation were to:
Understand the groundwater regime across the Site;
Understand the engineering properties of the subsoils, principally their permeability; and
Understand the potential implications to the surrounding environment and groundwater users.
1.2 Scope of Work
To achieve the objectives described above, the Site investigation included:
The installation of three groundwater monitoring wells targeting the regional aquifer;
Geotechnical/geological assessment of the underlying soil and stratum;
Geotechnical testing of targeted soil sampling; and
Hydrogeological and Geotechnical reporting.
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2 Background
2.1 Location
The Site is located at Lot 28734, Reserve R25796 Inkpen Road, Copley, WA 6562, located within the Kwolyinine
Nature Reserve. The Site covers an area of approximately 15 hectares (ha) and is located 3 km south east of the
town of Wundowie within the Shire, and approximately 54 km to the east of Perth’s Central Business District
(CBD). The Site location is presented in Figure 1 and Figure 2.
2.2 Zoning and Surrounding Land Use
Under the Shire of Northam Local Planning Scheme No. 6 (District Scheme), the Site is zoned as 'Public Purpose-
Rubbish Disposal', with the surrounding areas zoned as a Local Reserve, more specifically a 'Conservation of Flora
and Fauna' area. This corresponds to the Kwolyinine Nature Reserve, see Figure 3.
2.3 Environmental Attributes
2.3.1 Climate
The Site is located within a region that experiences a Hot Mediterranean climate, with warm dry summers and
cool wet winters. The closest weather station to the Site, that has recorded longer term weather conditions, was
the facility located at Bakers Hill. However, this facility only presented data up until 1985. Therefore, in order to
provide a more current and robust data set, the facility located within Northam was used. The monthly averages
for both temperature and rainfall are presented in the following graph.
Graph 1: Climatic Data
Bureau of Meteorology (BoM) website (2017). The above data was recorded at Northam weather station (1902 to 2017 for temperature,
1877 to 2017 for rainfall).
0
10
20
30
40
50
60
70
80
90
0
5
10
15
20
25
30
35
40
mm
Deg
rees
Cel
siu
s
Climatic Data
Mean Maximum Temperature Mean Minimum Temperature Mean Rainfall
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An assessment of the meteorological conditions has shown the summer months of January and February to be
the warmest and driest, while the winter months of July and August were shown to be the coldest and wettest
period.
2.3.2 Site Conditions
The Site is currently used as a Class II waste management facility with associated infrastructure. The central Site
area is occupied by the main landfilling cell, with several stockpiles noted within the northern portion of the Site,
likely associated with waste stockpiles. Access tracks associated with the facility dissect the Site, with all roads
being unsealed. Large trees generally flank the perimeter of the Site.
2.3.3 Topography
The Australian Government National Map (http://nationalmap.gov.au/) dataset on a 1:250,000 scale shows that
the Site and surrounds are relatively flat, sitting at approximately 300 m Australian Height Datum (AHD).
Crossland & Hardy Pty Ltd undertook a topographical survey of the Site in August 2016. The survey data showed
that the highest elevation is located in the south east corner of the Site, which reaches approximately 318 m
AHD. The Site slopes down from this point to the north western corner of the Site which sits at approximately
295 m AHD. The topographical data is presented in Figure 4.
2.4 Geology
2.4.1 Quaternary Geology
The Department of Mines, Industry Regulation and Safety (DMIRS), previously known as the Department of
Mines and Petroleum (DMP), GeoView Atlas (https://geoview.dmp.wa.gov.au/GeoViews/?Viewer=GeoVIEW)
highlighted the underlying regolith soils to be “residual or relict material, including ferruginous, siliceous and
calcareous duricrust”. The underlying regolith/superficial soils are presented in Figure 5.
2.4.2 Archean geology
The DMIRS GeoView Atlas described the underlying hard rock geology as “South West Terrane Greenstones”,
forming part of the Yilgarn Craton. It is likely to consist of high grade metamorphic granulites and migmatites.
The underlying hard rock geology is presented on Figure 6.
2.4.3 Structural Geology
No major linear structure were identified within the confines of the Site, or the immediate surround area. No
information has been sourced on the dip or strike of the underlying lithologies.
2.5 Hydrogeology
2.5.1 Hydrogeology
Hydrogeological data is limited for the Site and its surrounds. The Australian Government National Map
(http://nationalmap.gov.au/) identifies that groundwater in the region flows through fractured rocks, see Figure
7.
2.5.2 Groundwater Use
The Department of Water (DoW) Water Information Reporting (WIR) Portal
(http://wir.water.wa.gov.au/Pages/Water-Information-Reporting.aspx) highlighted six registered bores to be
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located within a 2 km radius of the Site, see Figure 7. Of these, four were noted to be wells, while the remaining
two were noted as surface water sampling locations associated with Weerrirbee Brook (Wundowie Foundry)
and Coates Gully (DoW). Outside of the 2 km radius, numerous bores exist, likely associated with the agricultural
nature of the surrounding area. Users of any groundwater within this area will likely be in a non-potable,
irrigation and/or livestock setting. However, The Australian Government National Map
(http://nationalmap.gov.au/) highlighted that the underlying groundwater would likely be saline in nature, with
a salinity value >3,000 mg/L. A salinity value in this region would limit the beneficial use of any groundwater in
the area.
2.5.3 Hydrology
The Site is located within the Swan River Surface Water Proclaimed Area. No surface water bodies were noticed
within the confines of the Site. The closest surface waterbody is the Coates Gully which flows north, east and
west of the Site, with its closest part approximately 1.2 km to the west of the Site, see Figure 8. Beyond this,
they are numerous dams associated with agriculture within a 2 km radius of the Site.
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3 Project Methodology
3.1 Intrusive Investigation
The intrusive investigation was undertaken between 8-10 August 2017, and consisted of the following:
Sinking of three soil bores to a maximum 42 m depth below ground level (bgl) for geotechnical
purposes;
Conversion of the three soil bores into groundwater monitoring wells; and
Collection of representative soil samples from appropriate horizons as part of the geotechnical
investigation.
3.2 Drilling Techniques
All bores were sunk using a Hanjin D8 drilling rig utilising Rotary Air drilling methods through superficial soils,
and 3 inch downhole hammer through bedrock. This drilling method, which is a semi-destructive drilling method,
allowed for the broad assessment of the subsoil and underlying rock, and the collection of disturbed bulk soil
samples.
All field work, including the logging of the subsurface profiles and collection of soil samples, were undertaken
by an experienced geo-environmental engineer from Talis. The soil profile was logged in accordance with the
following standard:
Australian Standard (AS) 1726:1999-Geotechnical Site Investigation.
The subsurface conditions are summarised in Section 4.1.
3.2.1 Soil Testing
To assess the subsoil conditions, laboratory analysis on selected disturbed samples recovered during the
fieldwork was undertaken. This comprised of the following testing:
AS 1289.3.6.1, Soil Classification test- Determination of the particle size distribution of a soil-Standard
method of analysis by sieving;
AS 1289.3.6.3, Soil Classification test- Determination of the particle size distribution of a soil-Standard
method of fine analysis using hydrometer; and
AS1289.6.7.2, Soil Strength and consolidation testing-Determination of the permeability of a soil-Falling
head method for a remoulded specimen.
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4 Field Observations
The three soil bores were sunk to assess underlying geological profile and hydrogeological conditions beneath
the Site. The following section described the subsurface conditions, while Appendix A presents the engineering
logs with photographs presented in Appendix B. The Geotechnical laboratory results certificates are presented
in Appendix C. Their locations are presented in Figure 9.
4.1 Geology
The general underlying geology encountered during the sinking of the geotechnical bores/groundwater wells
can be summarised as follows:
GW01
Silty/sandy GRAVEL at the surface described as subangular to subrounded, poorly graded, iron lateritic
pisoliths with fine grained sand inclusions to 4 m bgl; underlain by
Clayey SILT, low plasticity and orange, beige, brown and red in colour. This horizon was encountered to
a depth of 24 m bgl; underlain by
Gravelly silty SAND, fine to coarse grained, subangular to subrounded, well graded and orange-beige in
colour. This horizon was encountered to a depth of 25 m bgl; underlain by
Sandy SILT with trace clay described as having a low plasticity. The sand was described as fine grained,
subangular to subrounded, poorly graded and brown in colour. This horizon was encountered to a
depth of 28 m bgl; underlain by
GRANITE, expressed as clayey SILT with trace sand, fine to coarse grained, subangular to subrounded
and brown and green in colour. Trace siltstone at depth.
GW02
Silty/sandy GRAVEL at the surface, described as subangular to subrounded, poorly to well graded, iron
rich siltstone. The sand proportion was described a fine grained, subangular to subrounded and orange
to red in colour, to 3.5 m bgl; underlain by
Gravelly/silty SAND, fine to coarse grained, subangular to subrounded, poorly to well graded and beige
to orange in colour. This was encountered to a depth of 6.5 m bgl; underlain by
Clayey SILT described as having a low plasticity and white in colour. This horizon was encountered to a
depth of 8.5 m bgl; underlain by
Silty SAND and sandy SILT layers. The sand was described as fine grained, subangular to subrounded,
beige and orange and brown in colour. It was encountered to a depth of 11.5 m bgl; underlain by
SILT with trace sand. The sand proportion was described as fine grained, subangular to subrounded and
white to grey in colour. This horizon was encountered to a depth of 18 m bgl; underlain by
GRANITE, expressed as silt to coarse grained sand, subangular to subrounded, well graded. Coarse
grained fragments are poorly cemented and beige to light brown in colour. This was encountered to a
depth of 35 m bgl.
GW03
Sandy GRAVEL and gravelly SAND at surface to a depth of 3 m bgl. This was described as fine to coarse
grained, subangular to subrounded, iron rich lateritic pisoliths and orange-brown in colour; underlain
by
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Clayey SAND. The sand proportion was described as fine to medium grained, subangular to subrounded,
gap graded. The clay proportion exhibited a low plasticity. Orange to beige in colour, to 4 m bgl;
underlain by
Clayey SILT described as having a low plasticity and beige to orange in colour. This horizon was
encountered to 4.5 m bgl; underlain by
Clayey silty SAND, fine to medium grained, subangular to subrounded, gap graded. Clay, low plasticity
and beige to orange in colour, to 5.5 m bgl; underlain by
Gravelly SAND, fine to coarse grained, angular to subrounded, well graded, iron rich lateritic pisoliths
and red to beige in colour, to 9 m bgl; underlain by
Clayey silty SAND and silty SAND interlayers, fine to coarse grained, subangular to subrounded, poorly
to well graded. The clay was described as having a low plasticity. Orange, white and brown in colour
and encountered to a depth of 16.5 m bgl; underlain by
Clayey SILT, low plasticity and red, orange and brown in colour. Encountered to a depth of 21 m bgl;
underlain by
Clayey silty SAND, further underlain by clayey SILT. The sand was described as fine to coarse grained,
subangular to subrounded, well graded. The cohesive material was described as having a low plasticity.
Red to brown in colour and encountered to a depth of to 24 m bgl; underlain by
Silty CLAY, low plasticity, orange to brown in colour and encountered to 25.2 m bgl; underlain by
GRANITE, presenting itself as silty SAND, silt to coarse grained with trace clay nodules. Interlocked
coarse crystals of quartz and feldspar and pyroxene and light grey in colour, to 35 m bgl.
4.2 Groundwater Well Construction Details
The three new groundwater monitoring wells were installed in accordance with the following standard:
ASTM D5092-04 Standard Practice for Design and Installation of Groundwater Monitoring Wells.
The construction details for the three groundwater wells installed by Soil Mechanics are provided in Table 4-1
below, with construction logs provided in Appendix A, with their location shown in Figure 9.
Table 4-1: Groundwater Well Construction Details
Well ID GW01 GW02 GW03
Installation date 08/08/2017 09/08/2017 10/08/2017
Well Depth 41.7 m 35 m
Bore/casing diameter 100 mm hole/ 50mm Class 18 PVC
Screen/casing construction
Screen length 6 m
Filter pack 3.2 mm washed silica placed
to 3.8 m above the screen
3.2 mm washed silica placed to 1.0 m
above the screen
Casing seal 1 m bentonite overlaying the washed silica
Well cover Up-rise lockable steel monument cover
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4.3 Survey Data
The three groundwater wells were surveyed by Handley Surveys on 18 August 2017. The Top of Casing (ToC) and
ground level at each location was surveyed to AHD, with details summarised in Table 4-2, with survey data
provided in Appendix D.
Table 4-2: Groundwater Well Survey Details
Well ID GW01 GW02 GW03
Northings 6483451.336 6483076.909 6483068.351
Eastings 443908.597 443915.993 444215.681
ToC RL (m AHD) 299.993 310.907 317.402
Ground level RL (m AHD) 299.345 310.316 316.833
4.4 Groundwater Depth and Flow Direction
Groundwater was not intercepted during the sinking of the three soil bores, or subsequent gauging by Talis.
Consequently, a groundwater assessment was not undertaken as part of this investigation.
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5 Geotechnical Laboratory Results and Assessment
Laboratory testing on soil samples was undertaken by E.Precision laboratories in their National Association of
Testing Authorities (NATA) accredited laboratory and consisted of the testing detailed in Section 3.
The laboratory test results, along with the test methods followed are presented in Appendix C, while results are
summarised in the following sections.
5.1 Soil Index Testing
PSD analysis results are summarised in Table 5-1 below.
Table 5-1: Soil Index
Location Depth (m
bgl) % Gravel
% Coarse
Grained
Sand
% Medium
Grained
Sand
% Fine
Grained
Sand
% Silt % Clay
GW01 8.0 m 1.8 14.9 34.8 21 19 8.5
GW02 12.0 m 0.2 3.51 22.3 12.8 52.2 9
GW03 10.0 m 0.0 1.5 6.5 10.6 73.9 7.5
Soil indexing generally confirmed the visual assessment, confirming the presence of sandy SILT with clay at GW02
and SILT with sand at GW03. Soil indexing at GW01 highlighted a higher percentage of sand, describing the
material as a silty SAND with clay instead of the SILT with clay.
5.2 Permeability
The falling head tests were scheduled on targeted horizons to ascertain the permeability of the underlying soils.
The outcome of this assessment is presented in Table 5-2 below.
Table 5-2 Falling Head Test Permeability
Sample ID GW01 GW02 GW03
Sample Depth 8.0 m 10.0 m 10.0 m 12.0 m 10.0 m 12.0 m
Permeability (m/s) 4.452x10-7 4.78x10-8 3.009x10-7 2.59x10-8 1.05x10-8 3.18x10-8
As shown in Table 5-2 above, the permeability was shown to range between 4.452 x 10-7 m/s and 1.05 x 10-8 m/s.
Permeability was shown to be related to the soil index, the higher permeability linked to the higher proportion
of sand. Permeability was also shown to decrease with depth at GW01 and GW02.
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6 Conceptual Site Model
In general accordance with the National Environment Protection (Assessment of Contamination) Measure
(NEPM, 2013), a tier 1 preliminary conceptual site mode (CSM) in relation to the risk to the potential
groundwater resource has been prepared for the Site. This combines the information from the investigation
undertaken and a literature review. This CSM identifies potential contamination sources, exposure,
transportation pathways and receptors that may exists within the vicinity of the Site.
6.1 Contamination Source
The source of contamination at the Site is the landfilled waste.
6.2 Contaminants of Potential Concern
Contaminants of potential concern (COPCs) that may be associated with landfilling vary depending on the buried
waste. The Department of Environment Regulation (DER) Assessment and management of contaminated sites
(DER, 2014) guidelines lists the following COPCs to associated with landfill sites:
PCBs;
Alkanes;
Sulfides;
Metals;
Organic Acids;
Nutrients (i.e. nitrogen, phosphorous);
Total Recoverable Hydrocarbons (TRH);
Polycyclic Aromatic Hydrocarbons (PAH);
Ammonia;
Total Dissolved Solids (TDS);
Benzene, toluene, ethylbenzene and xylenes (BTEX); and
Phenols.
6.3 Receptors
The following receptors have been identified:
Onsite – workers and visitors;
Onsite – groundwater resource;
Onsite – flora and visiting fauna;
Offsite – groundwater users down-hydraulic gradient;
Offsite – surface water users where groundwater from beneath the Site recharges to a surface water
body; and
Offsite – sensitive ecological receptors.
6.4 Transportation Mechanisms
Exposure pathways are means by which COPCs impact receptors. Exposure pathways for groundwater include:
Abstraction of groundwater;
Dermal contact;
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Ingestion;
Inhalation;
Movement down-hydraulic gradient; and
Uptake by groundwater dependent ecosystems.
6.5 Exposure Pathways and Qualitative Risk Assessment
Table 6-1 below identifies the receptor-exposure-pathways in relation to groundwater that may exist at the Site.
The level or risk has been determined by combining the consequence and the likelihood using the definitions
presented in AS310000:2009 Risk Management-Principles and Guidelines.
Table 6-1 Risk Assessment
Receptor Exposure Pathway
Pathway Complete/
Partially Complete/
Incomplete
Reasoning Risk
Site workers
and visitors to
the Site
Dermal Contact or
accidental inhalation
or ingestion of
groundwater
Incomplete
Groundwater is not abstracted
at the Site, therefore this
exposure pathway is
incomplete.
Low
Flora and
visiting Fauna
Absorption of
groundwater by flora,
dermal contact or
ingestion by fauna
Incomplete
Groundwater was not
intercepted during the
investigation. Due to the depth
to groundwater, there will be no
direct contact with deep rooted
flora and subsequent fauna
ingestion of potentially
impacted flora. The tree root
zone is anticipated to be located
within the shallow gravel layer,
which will be subject to
interactions via rain water
infiltration and not absorption
from the underlying
groundwater.
Low
Groundwater
users down
hydraulic
gradient
Dermal contact or
accidental inhalation
and ingestion of
groundwater
Incomplete
Groundwater was not
intercepted during the
investigation. Considering the
separation distance, coupled
with the relatively low
permeability of the underlying
soils, it is considered that the
risk to the groundwater
resource is low. Additionally,
there are no registered
groundwater wells within the
direct vicinity of the Site (<1km),
further reducing the risk to
Low
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Receptor Exposure Pathway
Pathway Complete/
Partially Complete/
Incomplete
Reasoning Risk
potential down-hydraulic users
of groundwater.
Surface water
users and
ecological
receptors.
Groundwater and
surface water
interactions
Incomplete
No surface water bodies were
noted within the confines of the
Site. The closest significant
water body is the Coates Gully,
located approximately 1.2 km to
the west of the Site. Given the
distance and depth to any
potential groundwater, it is
considered that surface water
and groundwater interactions
will be limited, resulting in a low
risk to sensitive receptors.
Low
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7 Discussion
The Site comprises an area of approximately 15 ha and is located at Lot 28734, Reserve R25796 Inkpen Road,
Copley, WA, within the Kwolyinine Nature Reserve, approximately 54 km to the east of Perth CBD. The Site is
an operational landfill, owned and operated by the Shire, whom are seeking approval to expand the facility to
include a Category 64 Class II Putrescible Landfill and Category 62, Solid Waste Depot.
Scope of Work
The hydrogeological and geotechnical investigation was undertaken in order to facilitate the above, as part of
the Works Approval. The investigation involved the sinking of three soil bores strategically located across the
Site, to a maximum depth of 42 m bgl. These bores were subsequently converted into groundwater monitoring
wells.
Soil Conditions
During the sinking of the soil bores, the initial soil profile encountered generally consisted of coarse grained
materials described as silty/sandy GRAVELs from the surface to 4 m bgl, further underlain by gravelly silty SAND.
Beneath these horizons, the soils were described as clayey SILT material with sand inclusions, likely representing
residual soils/extremely weathered bedrock. Bedrock was encountered within all bores at a depth of between
18 m bgl (GW02) and 30 m bgl (GW01), and was described as GRANITE.
Failing head permeability tests were conducted on targeted soil samples, with consideration to the current
landfill design and any future construction. This assessment was undertaken at depths of between 8.0 m bgl and
12 m bgl and suggested that the permeabilities were relatively low, varying between 4.452 x 10-7 m/s and 1.05
x 10-8 m/s, with permeability generally decreasing with depth.
Groundwater
In terms of beneficial use of groundwater in the area, four registered groundwater wells were shown to be
located within a 2 km radius of the Site. It is anticipated that these bores may be used in a non-potable, irrigation
or agricultural setting.
Following installation of the groundwater wells, a gauging event failed to encounter groundwater beneath the
Site. It is anticipated however, that a regional groundwater would exist at a greater depth within the granite
bedrock. Fractured rock aquifer such as this generally have a low yield and are of limited beneficial use due to
relatively high salinity, as suggested by the Australian Government National Map.
Risk Assessment
In terms of risk to groundwater users, it was considered that the risk is low, due to the separation distance (>1
km from the Site) to any potential groundwater user, the deep groundwater table (>42 m bgl) and low
permeability of the soils encountered at the Site. Additionally, no surface water bodies were located within the
vicinity of the Site (<1 km), with the nearest identified significant surface water body being the Coates Gully,
located approximately 1.2 km to the west.
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8 Conclusions and Recommendations
Based on the investigation undertaken, Talis has drawn the following conclusions:
The Site is currently an operational landfill, with the Shire anticipating future development of the Site
to include the construction of a Category 64 Class II Putrescible Landfill Cell and a Category 62 Solid
Waste Depot;
A total of three soil bores were sunk to a maximum 42 m depth for the purposes of geotechnically
assessing the underlying soils and bedrock;
All soil bores were converted into three groundwater monitoring wells for the purposes of a
hydrogeological assessment;
The near surface soils generally comprised of silty/sandy GRAVEL to a depth of 4 m bgl;
Underlying the gravel material, the profile included interbedded clayey, silty and sandy material to a
depth of between 18 m bgl and 30 m bgl;
The underlying bedrock was described as GRANITE;
Permeability assessments undertaken at depths of between 8.0 m bgl and 12 m bgl suggested that the
permeabilities were relatively low, varying between 4.452 x 10-7 m/s and 1.05 x 10-8 m/s, with
permeability generally decreasing with depth; and
Groundwater was not encountered at any of the three locations, though is anticipated to exist at a
greater depth within the granite bedrock;
Overall, there appears to be a low risk to sensitive receptors associated with the Sites operation as a landfill.
This is based on the Site’s location, being >1 km from possible sensitive receptors from a hydrogeological
perspective, the low permeability of the underlying soils and the groundwater table sitting >42 m bgl. In addition,
the construction of the new landfill cell will include modern engineering practices, therefore further reducing
the potential impacts to groundwater.
Hydrogeological and Geotechnical Investigation Inkpen Road Waste Management Facility Shire of Northam
TW17035-Inkpen Road Site Investigation_1a September 2017 | Page 15
References Australian Government National Map, http://nationalmap.gov.au/
Australian Standard (AS) 1726:1999-Geotechnical Site Investigation
AS 1289.3.6.1, Soil Classification test- Determination of the particle size distribution of a soil-Standard method
of analysis by sieving
AS 1289.3.6.3, Soil Classification test- Determination of the particle size distribution of a soil-Standard method
of fine analysis using hydrometer
AS1289.6.7.2, Soil Strength and consolidation testing-Determination of the permeability of a soil-Falling head
method for a remoulded specimen
Bureau of Meteorology, http://www.bom.gov.au/wa/?ref=hdr
Department of Mines, Industry Regulation and Safety (DMIRS) GeoView Atlas
https://geoview.dmp.wa.gov.au/GeoViews/?Viewer=GeoVIEW
Department of Environment and Regulation, Assessment and management of contaminated sites, 2014
Department of Water and Environmental Regulation, Water Information Reporting Portal
http://wir.water.wa.gov.au/Pages/Water-Information-Reporting.aspx
National Environment Protection (Assessment of Contamination) Measure, 2013
Hydrogeological and Geotechnical Investigation Inkpen Road Waste Management Facility Shire of Northam
TW17035-Inkpen Road Site Investigation_1a September 2017 | Page 16
Figures Figure 1: Locality
Figure 2: Site Aerial
Figure 3: Zoning
Figure 4: Topography
Figure 5: Quaternary Geology
Figure 6: Archean Geology
Figure 7: Hydrogeology
Figure 8: Hydrology
Figure 9: Bore Locations
Document Path: \\SERVER\Talis\SECTIONS\Waste\PROJECTS\TW2017\TW17035 - Northam - Inkpen Road\GIS\Maps\EAMP\TW17035_01_Locality_RevA.mxd
Douglas Rd
Inkpen Rd
Grea
t East
ernHw
y
W U N D O W I E
440,000
440,000
441,000
441,000
442,000
442,000
443,000
443,000
444,000
444,000
445,000
445,000
446,000
446,000
447,000
447,000
448,000
448,000
6,480
,000
6,480
,000
6,481
,000
6,481
,000
6,482
,000
6,482
,000
6,483
,000
6,483
,000
6,484
,000
6,484
,000
6,485
,000
6,485
,000
6,486
,000
6,486
,000
6,487
,000
6,487
,000
LEGEND
© Talis Consultants Pty Ltd ("Talis") Copyright in the drawings, information and datarecorded in this document ("the information") is the property of Talis. This document andthe information are soley for the use of the authorised recipient andthis document may not be used, transferred or reproduced in whole or partfor any purpose other than that which it is supplied by Talis withoutwritten consent. Talis makes no representation, undertakes no duty andaccepts no responsibility to any third party who may use or rely upon thisdocument or the information.
NorthamBakers Hill
WundowieChidlow YorkPerth
Armadale
Rockingham
Mandurah
0 20 40 60 80 100 120 14010km
LOCALITY
LOCALITY PLANInkpen Road WMF
Northam, WA
0 300 600 900 1,200150metres
¤ Coordinate System: GDA 1994 MGA Zone 50Projection: Transverse Mercator, Datum: GDA 1994
Reviewed:Checked:Prepared: F Walker Date: 12/09/2017
Revision:
Scale @ A3:1:30,000
Project No:TW17035A
Figure
01
Site Boundary
P PO Box 454, Leederville WA 6903 | A Level 1 660 Newcastle St, Leederville WA 6007 | T 1300 251 070 | W www.talisconsultants.com.au
N KingC Pelletier
Data Source: Imagery: Nearmap, 2017. Site Boundary: Cadastre, 2016.
Document Path: \\SERVER\Talis\SECTIONS\Waste\PROJECTS\TW2017\TW17035 - Northam - Inkpen Road\GIS\Maps\EAMP\TW17035_02_Aerial_RevA.mxd
Inkpen Rd
444,000
444,000
6,483
,000
6,483
,000
LEGEND
© Talis Consultants Pty Ltd ("Talis") Copyright in the drawings, information and datarecorded in this document ("the information") is the property of Talis. This document andthe information are soley for the use of the authorised recipient andthis document may not be used, transferred or reproduced in whole or partfor any purpose other than that which it is supplied by Talis withoutwritten consent. Talis makes no representation, undertakes no duty andaccepts no responsibility to any third party who may use or rely upon thisdocument or the information.
NorthamBakers Hill
WundowieChidlow YorkPerth
Armadale
Rockingham
Mandurah
0 20 40 60 80 100 120 14010km
LOCALITY
AERIAL PLANInkpen Road WMF
Northam, WA
0 25 50 75 10012.5metres
¤ Coordinate System: GDA 1994 MGA Zone 50Projection: Transverse Mercator, Datum: GDA 1994
Reviewed:Checked:Prepared: F Walker Date: 13/09/2017
Revision:
Scale @ A3:1:2,500
Project No:TW17035A
Figure
02
Site Boundary
P PO Box 454, Leederville WA 6903 | A Level 1 660 Newcastle St, Leederville WA 6007 | T 1300 251 070 | W www.talisconsultants.com.au
N KingC Pelletier
Data Source: Imagery: Landgate, 2017. Site Boundary: Cadastre, 2016.
Document Path: \\SERVER\Talis\SECTIONS\Waste\PROJECTS\TW2017\TW17035 - Northam - Inkpen Road\GIS\Maps\Geotech\TW17035_03_Zoning_RevA.mxd
W U N D O W I E441,000
441,000
442,000
442,000
443,000
443,000
444,000
444,000
445,000
445,000
446,000
446,000
447,000
447,000
6,481
,000
6,481
,000
6,482
,000
6,482
,000
6,483
,000
6,483
,000
6,484
,000
6,484
,000
6,485
,000
6,485
,000
LEGEND
© Talis Consultants Pty Ltd ("Talis") Copyright in the drawings, information and datarecorded in this document ("the information") is the property of Talis. This document andthe information are soley for the use of the authorised recipient andthis document may not be used, transferred or reproduced in whole or partfor any purpose other than that which it is supplied by Talis withoutwritten consent. Talis makes no representation, undertakes no duty andaccepts no responsibility to any third party who may use or rely upon thisdocument or the information.
NorthamBakers Hill
WundowieChidlow YorkPerth
Armadale
Rockingham
Mandurah
0 20 40 60 80 100 120 14010km
LOCALITY
ZONINGInkpen Road WMF
Northam, WA
0 200 400 600 800100metres
¤ Coordinate System: GDA 1994 MGA Zone 50Projection: Transverse Mercator, Datum: GDA 1994
Reviewed:Checked:Prepared: F Walker Date: 13/09/2017
Revision:
Scale @ A3:1:20,000
Project No:TW17035A
Figure
03
Site BoundaryZoning
Conservation of flora andfaunaLight and Service IndustryPublic PurposesRegional RoadRuralRural Residential
P PO Box 454, Leederville WA 6903 | A Level 1 660 Newcastle St, Leederville WA 6007 | T 1300 251 070 | W www.talisconsultants.com.au
N KingC Pelletier
Data Source: Imagery: Nearmap, 2017. Site Boundary: Cadastre, 2016.
Document Path: \\SERVER\Talis\SECTIONS\Waste\PROJECTS\TW2017\TW17035 - Northam - Inkpen Road\GIS\Maps\Geotech\TW17035_04_Topography_RevA.mxd
307
315.5
298
310
307 312
298.5
309.5
297
296
303.5
299.5
303.5
301
318
302
303
311303
303
304
314
304
311
308
300
308
305
306
308
309
299
297
307
298
296
312
295
305
313
305
305.5
305
298
309.5
296.5
299.5
308
314.5314.5313
300
307
312.5
298
317.5
297.5
296
312.5
311
306.5298
296.5
315
299301
302.5
303
309
314.5314.5
298
308.5
317
296.5
312.5
312.5
304.5
314
300.5
296
299.5
295.5
303.5
310
314
316.5
309
300298.5
309.5
316
303
304.5
314.5
313.5
305
315
315.5
296.5
304
313
309
315
314.5
305
308.5
314.5
306.5
306 307
313.5
306.5
303.5
295.5
296.5
298.5 299.5297.5
303.5
300.5
301.5
304.5
313.5
302.5
306.5
310.5
312.5
307.5
305.5
307.5
309.5
311.5
308.5
444,000
444,000
LEGEND
© Talis Consultants Pty Ltd ("Talis") Copyright in the drawings, information and datarecorded in this document ("the information") is the property of Talis. This document andthe information are soley for the use of the authorised recipient andthis document may not be used, transferred or reproduced in whole or partfor any purpose other than that which it is supplied by Talis withoutwritten consent. Talis makes no representation, undertakes no duty andaccepts no responsibility to any third party who may use or rely upon thisdocument or the information.
NorthamBakers Hill
WundowieChidlow YorkPerth
Armadale
Rockingham
Mandurah
0 20 40 60 80 100 120 14010km
LOCALITY
TOPOGRAPHYInkpen Road WMF
Northam, WA
0 20 40 60 8010metres
¤ Coordinate System: GDA 1994 MGA Zone 50Projection: Transverse Mercator, Datum: GDA 1994
Reviewed:Checked:Prepared: F Walker Date: 13/09/2017
Revision:
Scale @ A3:1:2,031
Project No:TW17035A
Figure
0 4
Site BoundaryElevation Contours (mAHD)
P PO Box 454, Leederville WA 6903 | A Level 1 660 Newcastle St, Leederville WA 6007 | T 1300 251 070 | W www.talisconsultants.com.au
N KingC Pelletier
Data Source: Imagery: Nearmap, 2017. Site Boundary: Cadastre, 2016.
Document Path: \\SERVER\Talis\SECTIONS\Waste\PROJECTS\TW2017\TW17035 - Northam - Inkpen Road\GIS\Maps\Geotech\TW17035_05_QuatGeology_RevA.mxd
R e s i d u a l
E x p o s e d
C o l l u v i u m
441,000
441,000
442,000
442,000
443,000
443,000
444,000
444,000
445,000
445,000
446,000
446,000
447,000
447,000
6,481
,000
6,481
,000
6,482
,000
6,482
,000
6,483
,000
6,483
,000
6,484
,000
6,484
,000
6,485
,000
6,485
,000
6,486
,000
6,486
,000
LEGEND
© Talis Consultants Pty Ltd ("Talis") Copyright in the drawings, information and datarecorded in this document ("the information") is the property of Talis. This document andthe information are soley for the use of the authorised recipient andthis document may not be used, transferred or reproduced in whole or partfor any purpose other than that which it is supplied by Talis withoutwritten consent. Talis makes no representation, undertakes no duty andaccepts no responsibility to any third party who may use or rely upon thisdocument or the information.
NorthamBakers Hill
WundowieChidlow YorkPerth
Armadale
Rockingham
Mandurah
0 20 40 60 80 100 120 14010km
LOCALITY
QUATERNARYGEOLOGY
Inkpen Road WMFNortham, WA
0 200 400 600 800100metres
¤ Coordinate System: GDA 1994 MGA Zone 50Projection: Transverse Mercator, Datum: GDA 1994
Reviewed:Checked:Prepared: F Walker Date: 13/09/2017
Revision:
Scale @ A3:1:20,000
Project No:TW17035A
Figure
05
Site Boundary1:500 000 State regolith (GSWA)
Exposed rock, saprolite, andsaprockResidual or relict material,including ferruginous,siliceous, and calcareousduricrustSlope deposits, includingcolluvium and sheetwash
P PO Box 454, Leederville WA 6903 | A Level 1 660 Newcastle St, Leederville WA 6007 | T 1300 251 070 | W www.talisconsultants.com.au
N KingC Pelletier
Data Source: Imagery: Nearmap, 2017. Site Boundary: Cadastre, 2016.