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Report onGeotechnical Assessment

Land Capability Assessment – Wilton JunctionHume Highway and Picton Road

Wilton

Prepared forWilton Junction Landowners Group

c/o Elton Consulting Pty Ltd

Project 73467.00June 2014

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Report on Geotechnical Assessment – Wilton Junction Project 73467.00 – Rev 6Hume Highway and Picton Road, Wilton June 2014

Executive Summary

This report, including Sections 1 to 18, is written in response to the NSW Department of Planning and Environment Draft Study Requirements (DSR), specifically DSRs 7 and 15, which state:

DSR 6 – Mine Subsidence (Part 2 only)

- Geotechnical analysis to ensure identified development areas and design parameters for housing and infrastructure are appropriate to manage impacts from mine subsidence and other geotechnical risks.

DSR 7 – Topography, soils and geology

- Analysis on the suitability of the proposed lakes and on-site water recycling facilities to ensure that water quality is managed tom minimise impacts to natural water sources and to the water regime / water availability for habitats.

- Analysis on maintaining environmental flows into the natural system from the urban areas and management of sediment, chemical and nutrient build up during low flow (drought) periods.

- Salinity assessment for building, water management and open space.

- Consideration of future land use zones to reflect appropriate levels of protection for ridges, waterways and other natural features.

DSR 15 – Agricultural land suitability (refer Appendix H)

- Undertake a high level study of the agricultural potential of the land. This report presents the results of a geotechnical assessment undertaken by Douglas Partners Pty Ltd (DP) as part of a greater land capability assessment for a 2741 hectare site, which forms the land parcel known as Wilton Junction, situated about the existing intersection of Picton Road and the Hume Highway in the suburb of Wilton. The work was commissioned by Mr Brian Elton of Elton Consulting Pty Ltd, the client’s representative and proponent, on 3 May 2013, on behalf of the client, the Wilton Junction Landowners’ Group (WJLG). It is understood that the site is subject to a rezoning application ultimately for the staged urban development in general accordance with the proposed master plan (prepared by Connor Holmes Property Services, Project No. 64127, dated 19 May 2014). The Master plan is shown as Figure 1 and indicates staged developments comprising approximately 11 000 to 13 000 residential dwellings, five schools, five shopping centres, commercial and retail facilities, community facilities, open spaces and associated roads and infrastructure, to be constructed over a period of approximately 30 years. To assist the rezoning application, DP has undertaken a high-level geotechnical assessment of the site to determine its suitability for urban development, with specific consideration given to the draft study requirements (DSRs) outlined by the NSW Department of Planning and Environment (refer DSRs 6, 7 and 15). The geotechnical investigation addressed the site’s geotechnical surface and subsurface conditions, slope instability risk potential, soil erosion risks, soil salinity, agricultural potential (undertaken by a sub-consultant) and geotechnical developmental constraints. The Wilton Junction Study Area covers 2741 hectares of land situated about the intersection of the Hume Highway and Picton Road, Wilton (refer Figure 2). The land is held by many title holders.

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Individual parcels range from large holdings held by significant land developers to individually owned rural and residential allotments. The current rezoning application is being undertaken as a collaborative approach essentially progressed by a consortium of four land developers, Lend Lease Communities (LLC), Bradcorp Wilton Park Pty Ltd (Bradcorp), Governor’s Hill (GH) and Walker Corporation Pty Ltd (WC), collectively known as the Wilton Junction Landowners’ Group (WJLG). Together, the WJLG own approximately 70% to 75% of the Wilton Junction site, with the remaining 25% to 30% owned by other small landholders. The land ownership can be seen on Figure 3. The 455 hectares currently controlled by LLC has already been rezoned and has progressed to staged construction (commenced in late 2006), with several development stages either complete or nearing completion. Accordingly, this part of Wilton Junction does not require consideration under the current assessment and thus Lend Lease is not a proponent for rezoning. The existing Wilton village has also been excluded from the assessment, as rezoning of this area is not required. In addition, smaller landholders are to be considered from a desktop perspective only due to site access constraints. A review of available geology maps for the site indicated that the central part of the Site is underlain by Ashfield Shale with some higher elevations possibly underlain by Bringelly Shale. The formations typical comprise laminite, siltstone, shale, carbonaceous claystone and coal in parts. Lower elevations and riparian zones within the site are underlain by Hawkesbury Sandstone, comprising medium to coarse-grained quartz sandstone, very minor shale and laminite lenses. The Mittagong Sandstone transitional member underlies areas of the site affected by the interface of the Ashfield Shale and Hawkesbury Sandstone formations. Soil landscape maps indicate that the site includes four soil landscape groups, including Blacktown, Lucas Heights, Hawkesbury and Luddenham soil landscapes. Mapping indicates that most of the site comprises soils of the Blacktown soil landscape, which is a residual soil landscape that comprises soils that are of low fertility, moderately reactive, highly plastic and generally low wet strength. Riparian areas of the site are within the Lucas Heights soil landscape (mapping unit lh), which is a residual soil landscape that comprises soils that are of low fertility, stony and slightly reactive and have low available water capacity. Areas surrounding the Nepean River, Cordeaux River and Allen Creek are within the Hawkesbury soil landscape. This is a colluvial soil landscape that comprises soils that are exhibit a high erosion hazard, are generally shallow, stony, highly permeable and of low fertility. Higher elevations at localised peaks are within the Luddenham soil landscape, which is an erosional soil landscape that comprises soils that are associated with a high soil erosion hazard, localised impermeable highly plastic subsoil and are generally moderately reactive. Subsurface conditions encountered during the geotechnical investigation confirmed the presence of the mapped soil types and rock formations. Soil types are generally clayey, with rock encountered mostly within 2 m of the existing ground surface. Laboratory test results undertaken on soil samples collected from the site indicated the soils to be general of medium to high plasticity, to have a predisposition to erosion and a moderate level of sodicity. Soils were found to be non-saline and generally non-aggressive to concrete or steel. Based on the results of the assessment thus far, the following summary points are noted:

No evidence of hillside/slope instability was observed within the proposed net developable area. It is considered that such instability does not impose significant constraints on the proposed site development under the current Master plan.

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The presence of erosive soils on site should not present significant constraints to development provided they are well managed during earthworks and site preparation stages.

No significant evidence of saline soil was identified within the site. Although further salinity testing is considered necessary, at this stage salinity levels are sufficiently low for this site to be deemed free of significant salinity constraints.

Although mild aggressivity to concrete is regularly encountered across the site, aggressivity levels are considered to be manageable, subject to appropriate design and construction consideration.

Highly sodic and sodic soils appear widespread and will require management to reduce dispersion, erosion and to improve drainage.

The results of the land capability assessment have not identified any issue that would preclude the rezoning of the Wilton Junction site for urban development.

The results of the land capability assessment to date have not identified any issue that would preclude the rezoning of the Wilton Junction site for urban development. Further investigation will, however, be required as the project progresses to development application and during project construction. Investigations would include (but not necessarily be limited to):

Additional salinity investigations for site soils and surface waters (i.e. dams) to increase the density of the data obtained to date. The investigation programme should be increased to compliment the current study and augment the findings to a frequency of testing satisfying one test pit location per one to two hectares, including additional full depth profile sampling and laboratory analysis. A cost effective way of conducting the salinity assessment would be to measure site conductivity using an electro-magnetic (EM) transceiver mounted to an all-terrain vehicle (ATV or quad-bike), thus reducing the number of test pits required for the assessment. This method would also significantly increase the number of conductivity readings measured and thus provide greater coverage of the site.

Additional investigation should be undertaken in development areas which are to be excavated deeper than 2 m or into rock at shallower depth, where direct sampling and testing of salinity has not been carried out. Salinity management strategies should then be reassessed following additional investigation by deep test pitting and/or drilling, sampling and testing for soil and water pH, electrical conductivity, TDS, sodicity, sulphates and chlorides.

Additional testing of the site’s soils and surface water (and groundwater, if encountered) for aggressivity testing and its effects on buried concrete and steel structures.

Additional testing of site soils for erosion and dispersion properties to provide better guidance on the design and construction of future water bodies and the ability of the soils to be used as clay liners, or similar.

Detailed geotechnical investigations on a stage-by-stage basis for determination of pavement thickness designs and lot classifications, as well as stage specific issues, such as deep excavations and construction of roads and dwellings/structures on steeper landforms and crests.

Routine inspections and earthworks monitoring during construction.


Table of Contents

Page

1. Introduction ...................................................................................................................... 1

2. Project Background ......................................................................................................... 3

3. Study Area ....................................................................................................................... 3

4. Land Ownership .............................................................................................................. 5

5. Background ..................................................................................................................... 7

5.1 Previous Works by Douglas Partners ................................................................... 7

5.2 Previous Works by Others .................................................................................... 8

6. Scope of Works for the Current Assessment .................................................................. 9

7. Site Description ............................................................................................................. 10

8. Site History .................................................................................................................... 11

8.1 Historical Aerial Photography .............................................................................. 11

8.2 Groundwater Bore Database .............................................................................. 12

9. Desktop Study ............................................................................................................... 13

9.1 Geology ............................................................................................................... 13

9.2 Soil Landscapes .................................................................................................. 13

9.3 Hydrogeology and Salinity .................................................................................. 14

10. Assessment and Field Work Methodology .................................................................... 15

10.1 Geotechnical ....................................................................................................... 15

10.2 Soil Salinity .......................................................................................................... 16

10.3 Additional Sampling and Testing ......................................................................... 16

10.4 Assessment Datum ............................................................................................. 16

11. Field Work Results ........................................................................................................ 17

11.1 Site Observations ................................................................................................ 17

11.2 Subsurface Conditions ........................................................................................ 18

11.3 Surface Water and Groundwater ........................................................................ 18

12. Laboratory Testing ........................................................................................................ 19

12.1 Geotechnical ....................................................................................................... 19

12.2 Salinity ................................................................................................................. 20

12.3 Additional Laboratory Tests ................................................................................ 24


13. Proposed Development ................................................................................................. 25

14. Comments ..................................................................................................................... 25

14.1 Slope Instability ................................................................................................... 25

14.2 Erosion Potential ................................................................................................. 26

14.3 Soil Salinity .......................................................................................................... 26

14.4 Soil Aggressivity .................................................................................................. 2714.4.1 Aggressiveness to Concrete .................................................................... 2714.4.2 Aggressiveness to Steel .......................................................................... 28

14.5 Sodicity ................................................................................................................ 28

14.6 Geotechnical Considerations .............................................................................. 2914.6.1 Site Classification .................................................................................... 2914.6.2 Footings ................................................................................................... 3014.6.3 Site Preparation and Earthworks ............................................................. 3014.6.4 Site Maintenance and Drainage .............................................................. 3114.6.5 Pavements ............................................................................................... 32

14.7 Soil and Water Management Plan ...................................................................... 33

14.8 Agricultural Potential ........................................................................................... 36

15. Further Investigation ...................................................................................................... 37

16. Summary of Land Capability for Site Development ....................................................... 37

17. Limitations ..................................................................................................................... 38

Appendix A: About this Report

Appendix B: Drawings 1 to 5

Appendix C: Site Photographs – Photos 1 to 31

Appendix D: Field Work Results – TP1 to TP45

Appendix E: Laboratory Test Results – Geotechnical

Appendix F: Laboratory Test Results – Salinity

Appendix G: CSIRO Guide to Home Owners on Foundation Maintenance and Footing Performance AGS, Australian Geoguides LR1 to LR9

Appendix H: Agricultural Land Capability Study (Report by Harvest Scientific Services P/L, Job Ref 201381, dated 30 May 2013)

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Report on Geotechnical Assessment Land Capability Assessment – Wilton Junction Hume Highway and Picton Road, Wilton 1. Introduction

This report presents the results of a geotechnical assessment undertaken by Douglas Partners Pty Ltd (DP) as part of a greater land capability assessment for a 2741 hectare site, which forms part of the land parcel known as Wilton Junction, situated about the existing intersection of Picton Road and the Hume Highway in the suburb of Wilton. The work was commissioned by Mr Brian Elton of Elton Consulting Pty Ltd, the client’s representative and proponent, on 3 May 2013, on behalf of the client, the Wilton Junction Landowners’ Group (WJLG). It is understood that the site is subject to a rezoning application ultimately for the staged urban development in general accordance with the proposed Master plan (prepared by Connor Holmes Property Services, Project No. 64127, dated 19 May 2014). The Master plan is shown as Figure 1 and indicates staged developments comprising approximately 11 000 to 13 000 residential dwellings, five schools, five shopping centres, commercial and retail facilities, community facilities, open spaces and associated roads and infrastructure, to be constructed over a period of approximately 30 years. To assist the rezoning application, DP has undertaken a high-level geotechnical assessment of the site to determine its suitability for urban development, with specific consideration given to the draft study requirements (DSRs) outlined by the NSW Department of Planning and Environment (refer DSRs 6, 7 and 15). The geotechnical investigation addressed the site’s geotechnical surface and subsurface conditions, slope instability risk potential, soil erosion risks, soil salinity, agricultural potential (undertaken by a sub-consultant) and geotechnical developmental constraints. In addition, DP concurrently completed a preliminary Phase 1 contamination assessment, with the results presented in a separate report titled Report on Phase 1 Contamination Assessment (refer Project 73467.00, dated 4 July 2013). The land capability assessment comprised site history searches, site inspections, non-intrusive and intrusive site investigations followed by laboratory testing of selected samples, engineering analysis and reporting. Details of the work undertaken and the results obtained are presented in this report, together with comments relating to land capability, engineering design and construction practice. Comments are also provided on the need for further geotechnical investigations that are required when the project progresses to the development application stage.

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Figure 1: Development Master plan

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2. Project Background

In November 2011, the NSW Government initiated the Potential Housing Opportunities Programme and invited landowners with suitably located substantial landholdings to nominate sites which might be able to deliver additional housing to address Sydney’s housing supply shortfall. Walker Corporation, Governors Hill, Bradcorp and Lend Lease responded to the programme and nominated landholdings of more than 100 hectares in Wollondilly Shire, surrounding the intersection of the Hume Highway and Picton Road for consideration. This area has subsequently become known as Wilton Junction, and is the subject of this application. Following a Wollondilly Shire Council resolution in May 2012, the four major landowners (collectively known as the Wilton Junction Landowners’ Group, WJLG) signed an agreement to work cooperatively with Wollondilly Shire Council (Council) to prepare a high level Master Plan for Wilton Junction to deliver high quality new housing, jobs close to homes, supporting social and utilities infrastructure and services, and a range of complementary land uses. A high level Master Plan and a Preliminary Infrastructure Requirements Report were considered by the Council on 17 December 2012, with Council resolving to give in-principle support to the proposal. Council also resolved to request that the rezoning be a state-driven process. Subsequently, the NSW Government decided to coordinate the statutory planning process, led by the Department of Planning and Infrastructure (now the Department of Planning and Environment, DP&E). The Minister for Planning and Infrastructure (now the Minister for Planning and Environment) proposed to prepare a State Environmental Planning Policy (SEPP), as per Section 24 of the Environmental Planning and Assessment Act 1979 (EP&A Act), which identifies that a SEPP is an Environmental Planning Instrument, and Section 37 of the EP&A Act, which relates to the making of a SEPP for State or regional significant development. This was done with a view to rezone the land through an amendment to the Wollondilly Local Environmental Plan 2011 (LEP) to facilitate the early delivery of housing and infrastructure, linked to an agreed Infrastructure, Servicing and Staging Plan. The Department of Planning and Infrastructure issued Key Study Requirements (KSRs) to the Proponents (Walker Corporation, Bradcorp and Governors Hill) to guide the planning investigations for a new town at Wilton Junction. The KSRs set the criteria for carrying out environmental investigations across the Study Area (excluding both Bingara Gorge and the existing Wilton village which will not be affected by any proposed amendments to their current zoning and planning provisions). The investigations examine the potential for the Wilton Junction Study Area to be rezoned under a SEPP.

3. Study Area

The Wilton Junction Study Area covers 2741 hectares of land situated about the intersection of the Hume Highway and Picton Road, Wilton (refer Figure 2). The land is held by many title holders. Individual parcels range from large holdings held by significant land developers (i.e. WJLG) to individually owned rural and residential allotments. The 455 hectares currently controlled by LLC has already been rezoned and has progressed to staged construction (commenced in late 2006), with several development stages either complete or nearing completion. Accordingly, this part of Wilton Junction does not require consideration under the current

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assessment. The existing Wilton village has also been excluded from the assessment. In addition, smaller landholders are to be considered from a desktop perspective only due to site access constraints. Figure 2: Wilton Junction Study Area

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4. Land Ownership

There are four major landowners within the Investigation Study Area:

Bradcorp Pty Ltd (land at Wilton West)

Walker Corporation (lands south of Picton Road and east of the Hume Highway)

Governors Hill (land including the Wilton Aerodrome and lands on both sides of Picton Road west of the Hume Highway)

Lend Lease (land to the north-west of the Hume Highway-Picton Road intersection; but is excluded from the study requirements)

The Investigation Study Area also includes land by other private owners (excluding land in Bingara Gorge and Wilton village) as outlined in the table below; with a plan of the extent of ownership being provided below.

Landowner Gross area (ha) Net developable area (ha)

Lend Lease 455 240

Bradcorp 872.4 458.7

Governors Hill 175.3 123.5

Walker Corporation 405.2 230.3

Other landowners** 572.3 489.2

TOTALS 2480.2 1541.7 ** This comprises 113 other private landowners, excluding the new Bingara Gorge estate and the existing Wilton village, which will not be affected by any proposed amendments to the existing Wollondilly Shire Council planning provisions. For the purposes of this rezoning application, the Proponents include Walker Corporation, Governors Hill and Bradcorp. Lend Lease will continue with the planning and delivery of its Bingara Gorge community in Wilton, which is already zoned for residential development.

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Figure 3: Wilton Junction Study Area Landownership

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5. Background

5.1 Previous Works by Douglas Partners

The land controlled by LLC is known as the Bingara Gorge Estate. The author was actively involved with the geotechnical aspects of the rezoning application for Bingara Gorge, undertaken during the early to mid-2000s. Since development commenced in late 2006, DP has provided geotechnical, salinity and environmental services to the Bingara Gorge development and thus has developed considerable knowledge of the site and its surrounds. To date, DP has undertaken a considerable volume of work that has included:

An extensive array of geotechnical investigations for:

- Preliminary geotechnical appraisals and assessments of rock depths;

- Stability of incised gullies for localised infrastructure;

- Bridge investigations for existing and proposed bridges;

- Pavement and housing allotment investigations for new residential stages;

- Pavement investigation and design for new Picton Road and Pembroke Parade intersection;

- Proposed new township water reservoir sites;

- Sewage treatment plants and associated treatment ponds;

- 18 hole golf course and associated lakes and water bodies;

- Design and construction of major gas main crossing structures; and

- Golf viewing platforms, golf course club house and sales and information centres.

Provision of extensive geotechnical services during construction of all works undertaken to date, including:

- Engineering inspections and advice during construction of new lots, pavements, golf course, open space and other various structures;

- Geotechnical inspection and testing services for all stages of the development; and

- Preparation of work-as-executed documentation for new pavements, engineered filling and residential lot classifications.

Initial and ongoing salinity assessments, including:

- Phase 1 preliminary salinity assessments covering the whole of the Bingara Gorge site; and

- Phase 2 detailed salinity assessments for individual development stages.

Environmental assessments, including:

- Monitoring of water quality within existing natural creeks within and adjacent to the site; and

- Assessing the water quality within on-site water bodies, such as lakes and dams. DP’s ongoing involvement with the Bingara Gorge development has resulted in the gathering of extensive geotechnical, salinity and environmental knowledge of the site, which can then be used to represent and provide guidance on the actual and anticipated conditions of the surrounding lands within the study area.

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5.2 Previous Works by Others

A previous geotechnical report titled Preliminary Geotechnical Assessment, Proposed Rural Subdivision, “Condell Park”, Wilton, NSW (Ref No. 21/11702/AS512, dated 17 February 2003) [GHD 2003] prepared by GHD-Longmac was provided by the client’s representative to assist the geotechnical assessment. GHD 2003 was undertaken for approximately 1300 hectares of land including the Bradcorp land on the north-western side of the Hume Highway and the existing Bingara Gorge development site. DP’s review of the report noted the following:

The description of the site, as presented by GHD, is generally consistent with those observed by DP during the current site assessment;

The assessment included a review of “readily available published geological data and maps”, “study and interpretation of aerial photographs”, a review of a previous GHD report for the site, as well as a report prepared by Mitchell McCotter & Associates titled ‘Coal Issues’, dated 1991, and a site walkover inspection;

Details of geological formations, terrain, topography and soil types presented in the report are generally consistent with those determined during the current study;

Geotechnical constraints were generally reported, as follows:

- “the site is not significantly constrained by surface features in the context that residential development is anticipated within the shale and sandstone areas, subject to limitations imposed by topography”;

- “Steep sided rocky watercourses and drainage lines [i.e. incised gullies] should not be developed because of their level of risk from instability”;

- A very low to low risk of instability was determined for most of the site, in accordance with the risk classification system published by the Australian Geomechanics Society (AGS 2000);

- A high risk was determined for steep side slopes within incised gullies and also for isolated areas of surface soil erosion;

- Preliminary site classifications in accordance with AS2870-1996 Residential Slabs and Footings of Class M (moderately reactive) to Class S (slightly reactive) were indicated for site areas underlain by shale bedrock, although Class H (highly reactive) areas were considered possible. Whereas Class S to Class A (sand and rock sites) site conditions were indicated for site areas underlain by sandstone bedrock, although Class M areas were considered possible;

- The site lies wholly within the Wilton Mine Subsidence District, with economical coal reserves identified below the site and nearby leases indicating coal reserves at depths in the order of 400 m below the ground surface. Future mining was expected, although no mining had occurred as at 2003;

- Topographic conditions such as the incised gullies and major highway bridges were suggested as possible constraints to limit future mining due to the risk of subsidence in the form of gully upsidence;

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- Longwall mining methods were considered very likely below the site and vertical subsidence of approximately 1.5 m was indicated, together with the effects of tilting, curvature and horizontal strain, the effects of which would need to be considered during the detailed design of structures;

- The drainage of coal seam gas (methane gas) from the Macarthur South region (existing Appin and Westcliff coal mines) was noted as an item for further consideration when assessing land use conflicts, although no specific discussions were presented.

GHD 2003 concluded that the “site is capable of being developed for rural residential purposes and for other types of residential development.” DP notes that any further discussion on the effects of coal mining and coal seam gas extraction are excluded from the current geotechnical assessment. It is understood that another consultant is addressing these items for the rezoning application. 6. Scope of Works for the Current Assessment

The task required by the geotechnical assessment phase of the land capability assessment comprises the identification of geotechnical constraints to urban development, particularly with respect to slope instability and erosion. Furthermore, a preliminary soil and water management plan (SWMP) is required to provide guidelines on procedures and development criteria that will apply during subdivision construction. It is noted, however, that the SWMP is preliminary only and will require further review and refinement once details of the development are finalised. DP has carried out salinity, contamination and agricultural potential assessments in conjunction with the geotechnical assessment. The results of the contamination assessment are reported separately, whereas the results of the salinity and agricultural potential studies are reported herein. The geotechnical, salinity and agricultural assessments were based on the following scope of work, which is considered to address the draft study requirements outlined by the NSW Department of Planning and Environment (refer DSRs 6, 7 and 15):

A review of published soils and geological information;

A scoping study of the site, comprising site inspections to identify potential zones for sample collection with regard to geotechnical factors;

Site walkover assessment by a Principal geotechnical engineer to identify areas of potential site instability, erosion risks and other geotechnical constraints;

A services search via the dial-before-you-dig service;

Location of the test pits and other site features by a Global Positioning System (GPS);

Excavation and logging of 45 test pits (TP1 to TP45);

Collection of disturbed samples of the soil and rock profiles intersected in the test pits to assist in strata identification and for laboratory testing;

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Laboratory geotechnical testing (in-house) of selected samples for a range of geotechnical properties, including moisture content, Atterberg limits (plasticity index), Emerson Class Number, textural classification and shrink swell tests;

Laboratory chemical testing (external) of selected samples for a range of chemical properties, including pH and electrical conductivity;

Storage of remaining soil samples pending the need for additional geotechnical or chemical testing and evaluation;

Preparation of constraints maps, indicating areas of site instability, erosion hazards and areas suitable for urban development;

Preparation of this report, outlining the scope of work undertaken, the results obtained, assessment of constraints, recommendations regarding management and mitigation issues and comments with respect to design and construction practice; and

Engagement of a sub-consultant, Harvest Scientific Services Pty Ltd (Harvest), to undertake an assessment of agricultural potential, which comprised their own desk top study and site walkover inspection.

The results of the geotechnical, salinity and agricultural potential studies are presented herein. A copy of the Harvest report is presented in Appendix H. 7. Site Description

The site lies within the Local Government Area of Wollondilly Shire Council (Wollondilly), and is understood, primarily, to be formed of approximately nine relatively large land holdings on either side of the Hume Highway north of Picton Road. There are also a number of smaller land holdings fronting the northern and southern sides of Picton Road both east and west of the Hume Highway (refer Drawing 1, Appendix B). Most of the site currently appears to be used for a mixture of rural/residential, agricultural and commercial purposes, although higher density residential development and an existing small commercial precinct are present within the existing Wilton village. The site is bounded to the north and west by the Nepean River, to the south by Cordeaux River and catchment lands, and to the east by Allens Creek and further agricultural, rural and residential lands. The site traverses undulating terrain with an overall relief of approximately 170 m from the highest part (approximately RL 280, relative to Australian height datum – AHD) of the site at the southern central part of the WC land to the lowest part (approximately RL 110), of the site at the northern end of Bradcorp land although ground surface levels are considerably lower (approximately RL 62) at the base of the steeply incised sandstone gullies associated with the Nepean River. Ground surface slopes within the site are typically less than ten degrees, often less than five degrees. Ground surface slopes steepen considerably within the gullies, often approaching near-vertical conditions along existing sandstone cliff faces, although all steep gullies lie well outside the proposed development footprint. Most of the site is currently vacant rural land that is covered with grass and scattered to moderately dense natural tree growth with dense vegetation present around the perimeter of the site along the

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gully crests (refer Drawing 4 in Appendix B). Although the site is essentially undeveloped and appears to follow the inferred natural land form, historical aerial photographs suggest some degree of vegetation clearing. Prior rural grazing land use is also indicated by the presence of several existing rural dams and derelict farm sheds and paddock fences. A selection of general photographs of the site is presented in Appendix C (refer Photos 1 to 8). 8. Site History

The results of the site history study conducted as part of the contamination assessment are presented in the DP’s Report on Phase 1 Contamination Assessment. Relevant excerpts of the study are presented below. 8.1 Historical Aerial Photography

Aerial photographs were reviewed to identify any historic changes to the landscape, which may affect the geotechnical condition of the site. Seven aerial photographs were reviewed from the years 1955, 1961, 1975, 1984, 1990, 2005 and 2010. A summary of the aerial photograph review is given below.

1955: In 1955 most of the site had been cleared with one small cluster of buildings located within the Wilton village area. Individual homesteads were present along Wilton Park Road. Wilton Park Road alignment was present and could be seen running in a west to east direction. The site was densely vegetated around the edges and within the gully areas. Some dams and gravel tracks were present across the site indicating a potential for some agricultural land usage. Recently cleared or logged areas were observed within the northern and eastern portions of the site.

1961: The site appears to have remained relatively unchanged with the exception of more extensive land clearing within the northern and eastern portions of the site. Some ground disturbances are noticeable at various locations across the site in the 1961 photograph.

1975: The site appears to have remained relatively unchanged since the previous photograph with the exception that the rural allotments are more clearly defined (some with residential dwellings) along Wilton Park Road in the western portion of the site. Residential dwellings appear to have been constructed on some of these lots. Since the previous photograph, Wilton village appears to have expanded with the addition of further residential dwellings. Some ground disturbances were noted across the site and included a dirt track (possibly a runway) extending in a north south direction in the vicinity of the current airfield. Land clearing was observed to the north of the cluster of residential buildings observed in Wilton and to the south of Wilton Park Road in the western portion of the site.

1984: Most of the site appears to have remained relatively unchanged since the previous photograph. The Hume Highway has been constructed, as has Picton Road, which extends from the north of the site to Wilton village. Wilton village has increased in size with addition of further residential buildings. The alignment of Wilton Park Road has altered due to the construction of the Hume Highway and Picton Road. There appears to have been a new access road to the airfield and an additional runway constructed since the previous photograph. An unsealed access road can be seen extending past the

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airfield and to the north within the rail corridor. The access leads to a large area of ground disturbance where the construction of the rail bridge appears to have commenced. Some ground disturbances are apparent adjacent to the access road.

1990: The site appears to have remained relatively unchanged since the previous photograph. The southern portion of Picton Road has been constructed and extends east beyond Wilton village. An additional runway has been constructed roughly perpendicular to the existing (i.e. in a north west to south east direction). Some additional land clearing is evident in the central eastern portion of the site (to the north of the Wilton Township). The original runway appears to have been unused and is less noticeable. Some minor ground disturbances were noted within the site.

2005: The site appears to have remained relatively unchanged since the previous photograph. Disturbed ground is evident to the south of Picton Road and south of Wilton village, which appears to have been some kind of oval track.

2010: The site appears to have remained relatively unchanged since the previous photograph. In the vicinity of the airfield, the original runway can no longer be seen. The construction of the Bingara Gorge residential development has commenced since the previous photograph with roads and houses being constructed. Overall comments from the aerial photographs include:

Most of the site has remained vacant with the only likely land usage being agricultural, commercial (including the airfield and some areas within the current Wilton village) and some residential use;

The Hume Highway and Picton Road were constructed between the years 1975 and 1990;

Some ground disturbances were noted in the vicinity of the rail corridor and during the construction of the Rail bridge;

Numerous ground disturbances and dams were noted within the site; and

Recent land clearing was observed within the site. 8.2 Groundwater Bore Database

A search of the groundwater bore database administered by the NSW Office of Water indicated that there are eight bores located within the site. Work summaries from the bore search indicated that the authorised and intended purposes of the groundwater bores were for domestic stock, irrigation and test purposes. Groundwater was noted in one of the bores to the east of the site at a depth of 76 m below ground level. Groundwater was noted in the remaining wells at depths of 12 m and 24 m below ground level. For further details on the groundwater bores, please refer to DP’s Report on Phase 1 Contamination Assessment.

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9. Desktop Study

9.1 Geology

Reference to the 1:100 000 Wollongong-Port Hacking Geological Series Sheet (Ref 1) indicates that:

The central portions of the Site (as shown on Drawing 1) are underlain by Ashfield Shale (mapping unit Rwa) of the Wianamatta Group of Triassic age. This formation typically comprises laminite and dark grey siltstone.

Some minor areas of the site may be underlain by Bringelly Shale (mapping unit Rwb) of Triassic age. This formation typically comprises shale, carbonaceous claystone, laminite, and coal in parts.

The lower elevations and riparian zones within the site are underlain by Hawkesbury Sandstone (mapping unit Rh) of Triassic age. This formation typically comprises medium to coarse-grained quartz sandstone, very minor shale and laminite lenses.

In addition, it is known from geotechnical investigations undertaken for the Bingara Gorge development that the Mittagong Formation also underlies the site and forms a transitional geological sequence between the Ashfield Shale and Hawkesbury Sandstone. The Mittagong Formation typically up to 6 m thick and comprises interbedded shale, laminite and fine-grained quartz sandstone. The approximate geological boundaries, as shown on the geology map and inferred from site investigation, are shown on Drawing 1. 9.2 Soil Landscapes

Reference to the 1:100 000 Soil Landscapes of Wollongong-Port Hacking Sheet (Ref 2) indicates that the site includes four soil landscape groups, including the Blacktown, Lucas Heights, Hawkesbury and Luddenham soil landscapes. The approximate soil landscape boundaries, as shown on the soil landscape maps, are shown on Drawing 2, in Appendix B. Mapping indicates that most of the site comprises soils of the Blacktown soil landscape (mapping unit bt), which is characterised by topography of gently undulating rises on Wianamatta Group Shale, with local relief to 30 m and slopes usually less than 5%, typically represented by broad rounded crests and ridges with gently inclined slopes. This is a residual soil landscape, which the mapping indicates comprises multiple soil horizons that range from shallow red-brown podzolic soils comprising mostly clayey soils on crests and upper slopes, to deep brown to yellow clay soils on mid to lower slopes and in areas of poor drainage. These soils are typically of low fertility, are moderately reactive, highly plastic and generally have a low wet strength. The riparian areas of the site are within the Lucas Heights soil landscape (mapping unit lh), which is characterised by gently undulating crests and ridges on plateau surfaces of the Mittagong Formation (alternating bands of shale and fine-grained sandstones), with local relief to 30 m and slopes usually less than 10%. This is a residual soil landscape, which the mapping indicates comprises moderately deep, hard-setting yellow podzolic soils comprising clay, sandy clay and clayey sand and yellow ‘earths’ on outer edges of crests. These soils are typically of low fertility, stony and slightly reactive and have low available water capacity.

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Areas surrounding the Nepean River, Cordeaux River and Allen Creek are within the Hawkesbury soil landscape (mapping unit ha), which is characterised by rugged, rolling to very steep hills on Hawkesbury Sandstone, with local relief of 40 m to 200 m and slopes usually greater than 25% and rock outcrops of more than 50%. This is a colluvial soil landscape, which mapping indicates comprises multiple soil horizons, including localised yellow and red podzolic soils associated with shale lenses, siliceous sands and yellow earth along drainage lines, shallow and discontinuous sands associated with rock outcrops and some yellow podzolic soils on the insides of benches and along rock joints and fractures. These soils are typically associated with an extreme soil erosion hazard, mass movement (rock fall) hazard, steep slopes, rock outcrop or shallow, stony, highly permeable soil of low soil fertility. Areas of higher elevation and localised peaks are within the Luddenham soil landscape (mapping unit lu), which is characterised by undulating to rolling low hills on Wianamatta Group shales, often associated with Minchinbury Sandstone, with local relief of 50 m to 80 m and slopes generally between 5% and 20% typically represented by narrow ridges, hillcrests and valleys. This is an erosional soil landscape, which mapping indicates comprises multiple soil horizons, including moderately deep yellow podzolic soils and prairie soils on lower slopes and drainage lines, shallow dark podzolic soils or massive earthy clays on crests and moderately deep red podzolic soils on upper slopes. These soils are typically associated with a high soil erosion hazard, localised impermeable highly plastic subsoil and are generally moderately reactive. 9.3 Hydrogeology and Salinity

McNally (2005, Ref 3) describes some general features of the hydrogeology of Western Sydney which are relevant to this site. The shale terrain of much of Western Sydney is known for saline groundwater, resulting either from the release of connate salt in shales of marine origin or from the accumulation of windblown sea salt. This salt is concentrated by evapo-transpiration and often reaches highest concentrations in the B-horizon of residual soils. The B-horizon at the site is between 0.8 m and 2 m below ground level and typically underlies the topsoil unit. In areas of urban development, this can lead to damage to building foundations, lower course brickwork, road surfaces and underground services, where these affect the saline zone or where the salts are mobilised by changing groundwater levels. Seasonal groundwater level changes of 1 m to 2 m can occur in a shallow regolith aquifer or a deeper shale aquifer due to natural influences, however, urban development should be carried out with a view to maintaining the natural water balance (i.e. between surface infiltration, runoff, lateral through-flow in the regolith, and evapo-transpiration) so that long term rises do not occur in the saline groundwater level. The former Department of Environment Climate Change (DECC), now the NSW Environment Protection Authority (EPA), infers a “not observed” salinity potential for the site on their salinity hazard map extracted from the Soil and Land Resources of the Hawkesbury Nepean Catchment (DECC 2008) (Ref 4). The mapping is based on soil type, surface level and general groundwater considerations but is not generally ground-truthed, hence actual soil salinity needs to be assessed to confirm the DECC potential salinity mapping indication. Approximate salinity potential boundaries, as shown on the salinity potential map, are shown on Drawing 3, in Appendix B.

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10. Assessment and Field Work Methodology

Based on the brief provided by the client representative, Elton Consulting, DP identified the following scope of works for the site. 10.1 Geotechnical

The initial stage of the geotechnical study comprised the collection and review of background information, predominantly from aerial photographs, published maps and company data, including that obtained during detailed investigations undertaken within the Bingara Gorge site. A scoping study of the site, comprising a site walkover and field mapping by a senior geotechnical engineer was then undertaken to identify site areas that are potentially unstable, affected by salinity and/or erosion, and to finalise the proposed test pit locations for the subsurface investigation. Surface and subsurface investigations included:

Dial before you dig services search, survey set out by GPS and on-site scanning for buried services;

Excavation of 45 test pits across the proposed 812.5 hectare net development area;

Dynamic cone penetrometer (DCP) tests adjacent to selected test pits to aid the assessment of in-situ soil strength; and

Collection of representative bulk and undisturbed soil samples from the test pits for geotechnical laboratory analysis.

Test pits were excavated by a backhoe, fitted with a 450 mm wide toothed bucket. Test pits were excavated to a maximum depth of 2.7 m or until moderate resistance of the bucket was noted on weathered rock, which generally occurred within 1 m of the rock surface and was reached at depths of between 0.6 m and 2.7 m. Test pits were reinstated by placing the excavated soils back in the hole in the reverse order to which they were removed. The back of the backhoe bucket was then used to tamp down the soils in layers to reduce the amount of settlement within the test pit footprint following completion of the field work. The upper surface of the test pit was rolled by the backhoe tyres and where possible, was left slightly mounded above the surrounding ground surface to further reduce the effects of settlement. DCP testing was undertaken adjacent to 13 of the 45 test pits and extended to depths of between 0.6 m and 1.05 m. Geotechnical sampling from the test pits included large bulk, small disturbed and undisturbed 50 mm diameter tube samples. A selection of the samples was then scheduled for a variety of laboratory tests including field moisture content, Atterberg limits, Emerson class number, shrink-swell index and soil texture classification to assist the geotechnical assessment. The scope of the geotechnical investigation was designed to address the various issues under consideration in the land capability assessment. These included slope instability, erosion and sedimentation, geotechnical development constraints, earthworks requirements, AS2870-2011 (Ref 5) site classification, typical pavement thicknesses and site drainage.

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10.2 Soil Salinity

The salinity assessment comprised the collection and review of background information, including aerial photographs, published maps and company data. A site walkover inspection by a senior geotechnical engineer was then undertaken to identify site areas that are potentially affected by salinity and to map their location. Surface and subsurface salinity investigations included:

Concurrent use of all test pits excavated for the geotechnical investigation for salinity purposes; and

Collection of soil samples from all test pits for salinity laboratory analysis. Salinity sampling from the test pits included collection of small disturbed samples. A selection of the samples was then scheduled for a variety of laboratory tests including pH and electrical conductivity (EC). The guideline for undertaking salinity assessments on land proposed for urban development (Site Investigations for Urban Salinity – Department of Land and Water Conservation 2002) typically requires the excavation of test pits with full depth profile sampling on a frequency of one test location per hectare for detailed investigations for developments comprising medium intensity construction. This requires approximately 813 test pits to excavated across the net developable area of land owned by Bradcorp, GH and WC. Given the preliminary nature of the rezoning study, the “not observed” salinity potential obtained from the DECC map and the known non-saline condition of the Bingara Gorge development site (no saline soils identified to date), DP has undertaken a preliminary investigation, adopting a reduced number of test locations. Salinity sampling and laboratory testing was therefore undertaken at 45 test locations, thus providing a test frequency of approximately one per 18 hectares. This sampling frequency is considered adequate for the rezoning stage. Sampling targeted the upper 1 m of the soil profile, commonly 0.1 m, 0.5 m and 1 m depths at most test locations. This equated to full depth profile sampling at 21 of the 45 test pits due to the relatively shallow depth of the underlying bedrock and near-full depth profile sampling at a further 15 test pits whereby sampling occurred at approximately 0.5 m intervals but excluded the topsoil profile. 10.3 Additional Sampling and Testing

In addition, DP was asked to undertake additional soil sampling and laboratory testing to assist the assessment of on-site disposal of storm water and site irrigation being undertaken by others. The additional sampling and testing works included the collection of bulk and small disturbed soil samples from the upper 1 m of the soil profile. A selection of the samples was then scheduled for exchangeable sodium percentage (ESP), cation exchange capacity (CEC), phosphorous sorption (P-sorp) and permeability. 10.4 Assessment Datum

The coordinates of the field tests and other pertinent features were determined by use of a portable dGPS receiver, which indicated a typical accuracy of about 1 m. Horizontal positioning was

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referenced to the Map Grid of Australia 1994 (MGA94), Zone 56 datum. Vertical positioning was referenced to reduced levels relative to AHD, with levels at test locations recorded to the nearest 1 m, as derived from survey contours on available 2 m contour maps of NSW. 11. Field Work Results

11.1 Site Observations

The observations made during the various inspections of the site undertaken during and following the field investigation programme (May 2013) are summarised below:

The landform is predominantly gently sloping undulating terrain of gradual relief within the net developable area, although relief is significant if considering the whole of site extremes. Crests and gullies are mostly broad, although deep and steeply incised gullies are present along creek lines that border the northern, eastern and western sides of the site.

Several small and relatively isolated areas of minor soil erosion (refer Drawing 5 in Appendix B) were noted generally at higher elevations in areas represented by the Luddenham soil landscape. Erosion was generally limited to about 0.5 m depth and presented on the north-facing slopes of localised crests (refer Photos 9 to 20, in Appendix C). Areas affected by erosion were generally less than 1000 m2.

Rock outcrops were identified at several locations across the proposed net developable area, including at the ground surface of lower slopes that lead to the crest of the steep gullies, within excavations undertaken for construction of existing dams, within shallow broad gullies and at isolated locations across the mid to lower slopes (refer Photos 21 to 24, in Appendix C). Outcrops of sandstone are significantly more evident outside of the proposed development area and are extensive throughout the gullies that border the site.

Other than minor soil erosion, further signs of slope instability were not identified within the proposed net developable area, however, a high risk of rock fall and block detachment was noted on the western side of the Bradcorp land immediately north of the incomplete Maldon to Dombarton railway bridge either side of the Nepean River (refer Photo 25, in Appendix C). Such instability is likely to be present at several locations throughout the side slopes of the incised gullies.

The soil profile across the site is mostly of residual original and comprises silty clay and clay overlying shale and clay and sandy clay overlying sandstone bedrock. The residual soil is sometimes mottled and contains some ironstone gravel in places. Erosional soils are similar to residual soils, although colluvial soils tend to be more granular.

Several salt tolerant species are evident at site including paspalum, couch grasses and bulrushes. Although indicative of saline soil conditions, there were no significant signs of salt scalding, efflorescence, iron-staining, or extensive bare areas of soil. Vegetation was relatively healthy across the site with no significant die-back noted.

Some areas of abruptly changing vegetation (mostly grasses) were noted across the site, suggesting a possible progressive change from native to more salt tolerant species, although all vegetation appeared relatively healthy (refer Photos 26 to 29, in Appendix C). Abrupt changes in grasses can also be a sign of different underlying soil conditions.

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Water levels within the existing dams were relatively high, indicating recent wet weather conditions (refer Photos 30 and 31, in Appendix C), although grasses were generally dry but of apparent healthy growth.

11.2 Subsurface Conditions

The subsurface conditions observed in the test pits excavated at site were logged by DP’s geotechnical engineering staff. The results of the test pits and DCP tests are presented on the test pit logs included in Appendix D, together with explanation sheets describing classification methods and descriptive terms. The test pits encountered relatively uniform conditions underlying the site, with the succession of strata broadly summarised as follows:

FILLING – clayey silt filling with some grass and igneous gravel was encountered to a depth of 0.3 m in TP35;

TOPSOIL – silty clayey topsoil, clayey silty topsoil, sandy silty clayey topsoil and silty topsoil encountered to depths of 0.1 m to 0.5 m in all TPs, with the exception of TP35;

CLAY/SILT – silty clays, sandy clays, shaly clays, clays, clayey silts and sandy silts were encountered to depths of 0.3 m to 2.3 m in all pits with the exception of TP31 and TP42;

BEDROCK – weathered sandstone or shale was encountered in all pits to the depth of termination.

No free groundwater was observed in the test pits excavated during the field work programme. It is noted that the test pits were immediately backfilled on completion, which precluded long term monitoring of groundwater levels. Soil conditions were relatively uniform across the site and were generally as indicated by the soil landscape map (refer Drawing 2). Sandstone was present at lower elevations about the site perimeter, whereas shales were present in the central, elevated areas of the site. This is consistent with the geology map for the site (refer Drawing 1). In addition to the above soil profiles, filling should be expected within the existing dam walls and is likely to comprise a blend of the residual soils and upper weathered rock profiles. 11.3 Surface Water and Groundwater

Groundwater was not observed in any of the test pits excavated at site. Although test pits were immediately backfilled, preventing long term monitoring of groundwater levels, the moisture contents of the subsurface soils did not indicate free groundwater to be likely within the depth of the investigation. Given the elevation of the site above the adjoining creek lines, groundwater levels are expected to lie well below the ground surface.

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Surface water was identified only in the existing dams on the site (refer aerial photograph presented as Drawing 4 in Appendix B for dam locations). No other surface water bodies or ponded areas were evident during the field investigation. 12. Laboratory Testing

12.1 Geotechnical

Soil and weathered rock samples were collected from the test pits during the field investigation. Representative samples were selected to undergo the following suite of geotechnical tests:

Field moisture content tests – 12 samples;

Atterberg limits tests – 7 samples;

Shrink-swell index tests – 5 samples; and

Emerson Class Number tests – 12 samples. The results of these tests are presented in Appendix E and are summarised in Table 1. Table 1: Laboratory Test Results (Geotechnical)

Test Pit No.

Depth (m)

FMC(%)

SSI (Iss %)

LL(%)

PL(%)

PI(%)

ECN

TP1 0.5 22.1 - 51 22 29 5

TP6 0.5 23.6 - 51 29 22 5

TP10 0.5 22.0 - 54 27 27 5

TP17 0.5 21.5 1.1 - - - 3

TP18 0.5 22.0 - 62 26 36 5

TP22 0.5 24.0 1.5 - - - 6

TP24 0.5 21.1 - 53 22 31 3

TP27 0.5 29.4 2.5 - - - 6

TP30 0.5 23.5 - 53 26 27 6

TP36 0.5 18.7 1.2 - - - 3

TP39 0.5 28.2 2.8 - - - 2

TP44 0.5 16.9 - 55 23 32 3 Where: FMC = Field Moisture Content SSI = Shrink-swell Index LL = Liquid Limit PL = Plastic Limit PI = Plasticity Index ECN = Emerson Class Number The laboratory test results indicate medium to high plasticity, slight to moderate reactivity and some predisposition to dispersion and slaking. Linear shrinkage test results for the seven samples subjected to Atterberg limits testing ranged between 11% and 16.5%.

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The laboratory test results confirm the consistent clayey nature of the soils at the site and indicate soil classifications, in accordance with the unified soil classification system, corresponding to inorganic clays of medium to high plasticity (CH) and inorganic silts or fine sandy or silty soils (MH). The Emerson Class Number (ECN) for a soil relates to the potential for the soil to slake and disperse. Higher Emerson Class Numbers correspond to soils with a lower tendency to disperse. Emerson Class Numbers of 5 and 6 indicates a tendency for the soil to slake with a low susceptibility to dispersion. Emerson Class Numbers of 2 and 3 indicates a tendency for the soil to slake with some dispersion, possibly more when remoulded. 12.2 Salinity

Soil salinity is typically assessed with respect to electrical conductivity of a 1:5 soil:water extract (EC1:5). This value can be converted to ECe (electrical conductivity of a saturated extract) by multiplication with a factor dependent of soil texture ranging from 6 for heavy clays to 17 for sands. Richards (1954, Ref 6) and Hazelton and Murphy (1992, Ref 7) classify soil salinity on the basis of ECe. The salinity classes and their implications on agriculture are summarised in Table 2. Table 2: Soil Salinity Classification

Class ECe (dS/m) Implication

Non Saline <2 Salinity effects mostly negligible

Slightly Saline 2 – 4 Yields of sensitive crops affected

Moderately Saline 4 – 8 Yields of many crops affected

Very Saline 8 – 16 Only tolerant crops yield satisfactorily

Highly Saline >16 Only a few very tolerant crops yield satisfactorily

Following the field investigation, 102 soil samples were submitted to Envirolab Services Pty Ltd (Envirolab), a NATA accredited facility, for soil tests for salinity. Where undertaken, testing generally accorded with the guidelines presented in the Site Investigations for Urban Salinity booklet, as published in 2002 by the then Department of Land and Water Conservation (DLWC). Soil tests were performed for their physical and chemical properties and included pH, electrical conductivity (1:5) and soil texture classification, the latter undertaken internally by DP’s geological staff. Laboratory testing was performed on 102 soil samples collected from the test pits excavated at site. Soil samples were generally collected from depths of 0.1 m, 0.5 m and then at 0.5 m depth intervals to the rock surface, hence samples were collected from varying soil and rock profiles below the ground surface. Detailed test reports are presented in Appendix F. A summary of the test results is presented below in Table 3 (following pages).

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Table 3: Laboratory Test Results (Chemical)

TestPit No.

Depth (m)

EC1:5

(dS/m) Texture Class

ECe

(dS/m)pHw (1:5)

Comments

Salinity Acidity

TP1 0.1 0.016 Light Clay 0.1 6.2 Non-Saline Slightly Acidic

TP1 0.3 0.057 Light Clay 0.5 5.9 Non-Saline Mod. Acidic TP1 0.5 0.064 Light Medium Clay 0.5 6.2 Non-Saline Slightly Acidic

TP1 1.0 0.130 Medium Clay 0.9 5.5 Non-Saline Strongly Acidic

TP2 0.5 0.092 Light Medium Clay 0.7 5.6 Non-Saline Mod. Acidic TP2 1.0 0.072 Medium Clay 0.5 5.8 Non-Saline Mod. Acidic

TP3 0.5 0.026 Medium Clay 0.2 6.0 Non-Saline Mod. Acidic

TP3 1.0 0.220 Medium Clay 1.5 5.1 Non-Saline Strongly Acidic TP4 0.1 0.023 Clay Loams 0.2 6.2 Non-Saline Slightly Acidic

TP4 0.5 0.120 Light Clay 1.0 6.7 Non-Saline Neutral

TP5 0.5 0.038 Light Medium Clay 0.3 5.6 Non-Saline Mod. Acidic TP5 1.0 0.038 Medium Clay 0.3 5.7 Non-Saline Mod. Acidic

TP6 0.1 0.013 Light Clay 0.1 6.0 Non-Saline Mod. Acidic

TP6 0.5 0.039 Medium Clay 0.3 5.9 Non-Saline Mod. Acidic TP7 0.15 0.015 Light Clay 0.1 5.7 Non-Saline Mod. Acidic

TP7 0.5 0.049 Light Medium Clay 0.4 6.0 Non-Saline Mod. Acidic

TP8 0.1 0.094 Light Clay 0.8 5.6 Non-Saline Mod. Acidic TP8 0.4 0.120 Medium Clay 0.8 5.0 Non-Saline Strongly Acidic

TP9 0.1 0.010 Clay Loams 0.1 6.1 Non-Saline Slightly Acidic

TP9 0.5 0.021 Light Clay 0.2 6.4 Non-Saline Slightly Acidic TP10 0.1 0.020 Light Clay 0.2 6.0 Non-Saline Mod. Acidic


TP10 1.0 0.023 Light Clay 0.2 5.7 Non-Saline Mod. Acidic TP11 0.05 0.024 Clay Loams 0.2 6.0 Non-Saline Mod. Acidic


TP12 0.5 0.059 Medium Clay 0.4 5.6 Non-Saline Mod. Acidic TP12 1.0 0.290 Medium Clay 2.0 5.0 Non-Saline Strongly Acidic

TP13 0.5 0.022 Clay Loams 0.2 5.6 Non-Saline Mod. Acidic

TP13 1.0 0.020 Light Clay 0.2 5.4 Non-Saline Strongly Acidic TP14 0.5 0.079 Light Clay 0.7 5.3 Non-Saline Strongly Acidic

TP14 1.0 0.056 Light Medium Clay 0.4 5.4 Non-Saline Strongly Acidic

TP15 0.1 0.038 Loams 0.4 5.9 Non-Saline Mod. Acidic TP15 0.5 0.013 Clay Loams 0.1 6.1 Non-Saline Slightly Acidic

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Table 3 (continued): Laboratory Test Results (Chemical)

TestPit No.

Depth (m)

EC1:5


ECe

(dS/m)pHw (1:2)

Comments

Salinity Acidity

TP16 0.1 0.018 Clay Loams 0.2 6.1 Non-Saline Slightly Acidic

TP16 0.5 0.045 Light Medium Clay 0.4 5.9 Non-Saline Mod. Acidic TP17 0.5 0.057 Light Clay 0.5 5.6 Non-Saline Mod. Acidic


TP18 0.1 0.015 Clay Loams 0.1 6.2 Non-Saline Slightly Acidic TP18 0.5 0.120 Medium Clay 0.8 5.3 Non-Saline Strongly Acidic


TP18 1.5 0.110 Light Medium Clay 0.9 5.5 Non-Saline Strongly Acidic TP19 0.5 0.047 Light Medium Clay 0.4 5.4 Non-Saline Strongly Acidic


TP20 0.1 0.023 Clay Loams 0.2 6.2 Non-Saline Slightly Acidic TP20 0.4 0.023 Light Medium Clay 0.2 5.8 Non-Saline Mod. Acidic


TP21 1.0 0.059 Heavy Clays 0.4 5.7 Non-Saline Mod. Acidic TP22 0.5 0.029 Light Medium Clay 0.2 5.8 Non-Saline Mod. Acidic


TP23 0.5 0.042 Light Medium Clay 0.3 5.7 Non-Saline Mod. Acidic TP23 1.0 0.060 Light Medium Clay 0.5 5.4 Non-Saline Strongly Acidic

TP24 0.1 0.018 Clay Loams 0.2 6.6 Non-Saline Neutral

TP24 0.5 0.058 Light Medium Clay 0.5 6.3 Non-Saline Slightly Acidic TP24 1.0 0.095 Light Clay 0.8 6.1 Non-Saline Slightly Acidic

TP24 1.4 0.099 Clay Loams 0.9 8.4 Non-Saline Mod. Alkaline

TP25 0.5 0.042 Medium Clay 0.3 5.9 Non-Saline Mod. Acidic TP25 0.8 0.072 Medium Clay 0.5 5.7 Non-Saline Mod. Acidic

TP26 0.3 0.024 Medium Clay 0.2 6.9 Non-Saline Neutral

TP26 0.5 0.029 Medium Clay 0.2 5.9 Non-Saline Mod. Acidic TP27 0.1 0.019 Clay Loams 0.2 6.4 Non-Saline Slightly Acidic



TP28 0.5 0.043 Medium Clay 0.3 6.3 Non-Saline Slightly Acidic

TP28 1.0 0.140 Heavy Clays 0.8 5.7 Non-Saline Mod. Acidic TP29 0.5 0.063 Light Clay 0.5 5.4 Non-Saline Strongly Acidic

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TestPit No.

Depth (m)

EC1:5


ECe

(dS/m)pHw (1:2)

Comments

Salinity Acidity


TP30 0.5 0.110 Medium Clay 0.8 5.3 Non-Saline Strongly Acidic TP30 1.0 0.051 Medium Clay 0.4 5.7 Non-Saline Mod. Acidic

TP31 0.3 0.033 Loams 0.3 5.8 Non-Saline Mod. Acidic

TP32 0.5 0.028 Medium Clay 0.2 6.1 Non-Saline Slightly Acidic TP32 1.0 0.076 Medium Clay 0.5 5.3 Non-Saline Strongly Acidic


TP33 1.0 0.058 Medium Clay 0.4 5.8 Non-Saline Mod. Acidic TP34 0.5 0.034 Light Clay 0.3 5.8 Non-Saline Mod. Acidic


TP35 0.5 0.056 Light Medium Clay 0.4 5.5 Non-Saline Strongly Acidic TP35 1.0 0.096 Medium Clay 0.7 5.3 Non-Saline Strongly Acidic




TP37 0.5 0.120 Medium Clay 0.8 5.5 Non-Saline Strongly Acidic TP38 0.1 0.052 Light Clay 0.4 6.1 Non-Saline Slightly Acidic


TP39 0.1 0.028 Clay Loams 0.3 5.9 Non-Saline Mod. Acidic TP39 0.5 0.041 Light Medium Clay 0.3 5.6 Non-Saline Mod. Acidic


TP39 1.5 0.071 Medium Clay 0.5 5.4 Non-Saline Strongly Acidic TP40 0.5 0.050 Medium Clay 0.4 5.7 Non-Saline Mod. Acidic


TP41 0.2 0.051 Clay Loams 0.5 7.0 Non-Saline Neutral TP41 0.5 0.059 Light Medium Clay 0.5 5.7 Non-Saline Mod. Acidic

TP42 0.2 0.026 Loams 0.3 5.8 Non-Saline Mod. Acidic

TP43 0.5 0.150 Medium Clay 1.1 5.3 Non-Saline Strongly Acidic TP43 1.0 0.091 Medium Clay 0.6 5.3 Non-Saline Strongly Acidic


TP44 0.5 0.035 Light Clay 0.3 5.6 Non-Saline Mod. Acidic TP44 1.0 0.025 Light Clay 0.2 5.6 Non-Saline Mod. Acidic

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TestPit No.

Depth (m)

EC1:5


ECe

(dS/m)pHw (1:2)

Comments

Salinity Acidity


TP45 0.5 0.034 Medium Clay 0.2 5.5 Non-Saline Strongly Acidic TP45 1.0 0.052 Light Medium Clay 0.4 5.0 Non-Saline Strongly Acidic

Where EC1:5 = Electrical Conductivity ECe = Electrical Conductivity corrected for soil texture pHw = pH in water Mod. = Moderately To the extent that the 102 samples collected from 45 test pits are representative of the study area, the results indicate that non-saline conditions can be expected throughout the study area. The results are derived from salinity measurements in soils to depths of up to 1.5 m, which equates to full depth profile sampling in many of the test pits. 12.3 Additional Laboratory Tests

Additional soil samples were collected from the test pits during the field investigation to assist the assessment of on-site disposal of storm water and site irrigation being undertaken by others. Representative samples were selected to undergo the following suite of tests:

Exchangeable sodium percentage (ESP) – 6 samples;

Cation exchange capacity (CEC) – 6 samples;

Phosphorous sorption (P-sorp) – 6 samples; and

Permeability – 3 samples. The results of these tests are presented in Appendices E and F and are summarised in Table 4. Table 4: Laboratory Test Results (Storm Water Disposal and Irrigation)

Test Pit No.

Depth (m)

ESP(%)

CEC (meq%)

P-sorp(kg/ha)

Permeability (m/s)

TP3 0.4 – 0.7 3.0 9.8 9 400 3.0 x 10-10

TP18 1.0 14.5 4.3 8 200 -

TP24 1.0 11.7 8.4 5 000 -

TP29 0.4 – 0.7 5.8 8.1 9 800 8.6 x 10-10

TP33 1.0 12.2 6.6 6 400 -

TP37 0.5 17.9 4.0 9 800 6.4 x 10-10 Where ESP = Exchangeable Sodium Percentage CEC = Cation Exchange Capacity P-sorp = Phosphorous Sorption

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13. Proposed Development

It is understood that the site is subject to a rezoning application ultimately for the staged development in general accordance with the proposed Master plan. The Master plan is shown as Figure 1 and indicates staged developments comprising approximately 11 000 to 13 000 residential dwellings, five schools, five shopping centres, commercial and retail facilities, community facilities, open spaces and associated roads and infrastructure, to be constructed over a period of approximately 30 years. The following sections provide general comments on development constraints relevant to geotechnical factors and soil chemistry to assist in the conceptual planning of the site. Further investigations will need to be undertaken as the conceptual planning and design process continues, and if the project progresses to development application (refer Section 15). 14. Comments

14.1 Slope Instability

No evidence of slope instability (i.e. landslip, etc.) was observed within the site, which is consistent with the gently sloping landforms that typically provide hillside slopes with falls of 5 degrees or less across most of the site. Steeper ground surface slopes of up to 15 degrees are evident throughout the central and southern areas of the site and generally form side slopes of isolated hills and north facing slopes of crests, particularly those along the southern boundary of the WC lands. In addition, steeper ground surface slopes are present at or near the crests of the incised gullies that border the site, although these lie outside of the proposed net developable area. Steeper ground surface slopes are also present where modifications have been made to the landform, such as at excavation faces within existing dams and railway cuttings and at embankment batters associated with dam walls and the approach to the incomplete rail bridge at the western side of Bradcorp land. Localised ground surface slopes of up to 30 degrees were noted at these locations. Although these slopes are steeper than typically recommended for compacted or natural clayey soils, the current performance of the slopes appears adequate for their current use. Cut batters and embankments appear relatively stable, although they are affected by minor erosion, mostly due to a lack of appropriate vegetation cover, or other surface protection layer. Although a high risk of slope instability was identified in the form of rock fall along the crest of the steeply incised gullies along the northern, eastern and western boundaries, it is considered that such is sufficiently removed from the proposed development footprint for it not to be a concern. Therefore, it is considered that hillside instability does not impose significant constraints on the proposed site development. A stability hazard map has not been prepared, as no significant stability hazards were identified within the site.

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14.2 Erosion Potential

Soils of the Blacktown soil landscape are typically of moderate erodibility. The more sodic or saline soils of the Blacktown soil landscape can have a high to very high erodibility and the erosion hazard for this landscape is estimated as moderate to very high (Ref 2). The results of Emerson class number tests indicate a low to moderate risk of erosion. The soil erosion hazard for the Luddenham soil landscape is moderate to extreme and extreme respectively, for non-concentrated and concentrated flows. The soil erosion hazard for the Lucas Heights soil landscape within the site’s riparian zones is moderate and generally similar to that of the Blacktown soil landscape. The colluvial soils of the Hawkesbury soil landscape are estimated as having a moderate to high risk of erosion for non-concentrated flow, and very high for concentrated flow. Nine areas of active soil erosion were identified at the site during the site walkover inspection, with their locations shown on Drawing 5. In all instances, erosion scarring was less than 1 m deep (typically 0.5 m) and covered an area of less than 1000 m2. A selection of photographs showing the areas of soil erosion are included in Appendix C (refer photos 9 to 20). Given the presence of isolated, shallow soil erosion, development should avoid the construction of landforms that create a concentrated overland flow of surface waters. As this is not always possible, the following measures could be adopted to reduce the risk of soil erosion:

Placement of filling within overland flow paths using select materials (i.e. non–dispersive or least erodible) placed under controlled conditions;

Provision of a temporary surface cover within overland flow paths (e.g. biodegradable matting that is pegged in place) during the period of gully floor revegetation;

Construction of channel lining in sections of rapid change in gully floor grade;

Collection and discharge of water flows through a piped network, where appropriate; and

The re-establishment of an appropriate vegetated zone to protect the ground surface over the long-term.

It is considered that the erosion hazard within the areas proposed for urban development would be within usually accepted limits, and can be managed by good engineering and land management practices. 14.3 Soil Salinity

Methods of assessment of soil salinity were adopted to ground-truth the salinity potential map of DECC (2008, Ref 4) and included:

A site walkover inspection to locate and map visible indicators of salinity; and

ECe analysis of 102 laboratory tests on soil samples collected from 45 test pits. Although the salinity works undertaken during this study are preliminary, it is considered that the results obtained, together with DP’s knowledge of the Bingara Gorge development site for which only

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non-saline soils have been identified, provide a reasonable early indication of the actual salinity potential for the site. Further salinity studies will be necessary to achieve a greater density of test data, although the preliminary study did not identify any specific areas of concern with regards to urban development. The implication of screening of soil samples, as detailed in Section 10.2, is that non-saline soil conditions are present across the site. The results, however, are from a small statistical sample size and although considered adequate for the current rezoning application, they will require additional support at future development application before the site is considered free from salinity concern. So far, the test results appear constant with depth in terms of salinity, with all calculated values of ECe being within the non-saline range of less than 2 dS/m (refer Tables 2 and 3). Although groundwater was not encountered within the 45 test pits excavated during the field investigation, subsequent investigations will need to further assess the deeper soil and upper shale horizons with greater frequency to ensure potential saline soils are not transferred to the site surface, following earthworks, where surface water can freely dissolve and transport salt concentrations. Assessing these soils in terms of salinity values versus soil depth will greatly assist the overall site assessment. With respect to salinity risks, the site has been assessed and 102 samples have been tested, all indicating that non-saline conditions are present. Therefore, provision of salinity risk contours across the site is not warranted, as all areas lie below a contour of 2 dS/m. Salinity risk contours should be prepared only if further testing identifies salinity levels above the non-saline category. Preliminary salinity testing indicates that the salinity potential of this site would be within usually accepted limits, which could be managed by good engineering and land management practices. Based on the works undertaken to date, specific salinity management plans are not required for this site. 14.4 Soil Aggressivity

14.4.1 Aggressiveness to Concrete

To assess whether the site’s soils are potentially aggressive to concrete, the test results (Section 10.2, Table 3) were referenced to Table 6.4.2(C) of AS2159-2009 “Piling – Design and Installation” (Ref 8). Although four sets of criteria are tabled, including sulphate (SO4) levels in soil and water, pH values and chloride levels in water, the preliminary assessment is restricted to pH only, as the chemical analysis of sulphates and chlorides was not undertaken. For soils of low permeability that lie above groundwater, soil Condition B applies and Table 6.4.2(C) provides the exposure classification appropriate for the site’s soils. The laboratory test results for pH ranged between 5.0 and 8.4. Each sample’s test results were compared to the tabulated limits, with 72 of 102 samples (70.6%) returning pH values within the non-aggressive soil condition range. The remaining 30 samples had pH values of 5.0 to 5.5 and are therefore within the mildly aggressive range. Based on testing to date, this comparison shows that surface and subsurface soils are mostly non-aggressive to buried concrete, although mildly aggressive also given that the upper value for the mild category is pH 5.5. Accordingly, appropriate management strategies will require consideration when

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constructing concrete structures on mildly aggressive soils at the site. These should include the consideration by designers of the need to use more durable building elements in mildly aggressive (strongly acidic to very strongly acidic) soil.

14.4.2 Aggressiveness to Steel

To assess whether the site’s soils are potentially aggressive to steel, the test results (Section 10.2, Table 3) were referenced to Table 6.5.2(C) of AS2159-2009 “Piling – Design and Installation” (Ref 8). Although four sets of criteria are tabled, including pH values, chloride levels in soil and water and resistivity, the preliminary assessment is restricted to pH and resistivity only, as the chemical analysis of chlorides was not undertaken. For soils of low permeability that lie above groundwater, Condition B applies and Table 6.5.2(C) provides the exposure classification appropriate for the site’s soils. The laboratory test results for resistivity all exceeded 2000 ohm cm. Each sample’s test results were compared to the tabulated limits. All samples returned pH and resistivity values within the non-aggressive soil condition range. Based on testing to date, this comparison shows that surface and subsurface soils are typically non-aggressive to buried steel. 14.5 Sodicity

The sodicity of the soil (i.e. the proportion of exchangeable sodium cations as a percentage of total exchangeable cations) can be elevated due to salt content and can affect properties such as dispersion, erodibility and permeability. Sodicity was assessed by measurement of the exchangeable sodium percentage and total cation exchange capacity of six soil samples, one from each of six of the 45 test pits, for classification of the soil as non-sodic (<5% sodicity), sodic (5 - 15% sodicity) or highly sodic (>15% sodicity). Samples were taken from depths of 0.4 m to 1 m. Laboratory results indicate non-sodic to highly sodic conditions for the samples tested. Based on the presence and extent of the Blacktown and Luddenham soil landscapes, these soils are likely to represent the whole of the site. Accordingly, management strategies will be required to manage the exposure of sodic and highly sodic soils. Strategies should include the design and implementation of an appropriate site drainage system that prevents sodic and highly sodic soils from breaking down and changing the water balance/water movement regime at the site. The application of gypsum can also improve sodic soils by providing a better balance between sodium and calcium in the soil. The following management strategies should be applied in all areas of the site to reduce the effects of sodic and highly sodic soils:

The erosion hazard will be reduced by limiting the construction area size at any one time and clearly defining the area by barrier fencing upslope and sediment fencing downslope (to be installed before the commencement of construction activities);

Access areas should be clearly defined and limited in size while being considerate of the needs of efficient work areas. All site workers should clearly recognise these boundaries;

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The programming of development road works and major excavations should be managed to minimise the time of soil exposure, and to coincide with periods of anticipated lower rainfall (wherever possible);

The placement of excavated soils in filled areas in the sequence of excavation (i.e. to place potentially saline or sodic subsoils below a capping of non-saline, non-sodic material);

The inclusion of techniques such as spray coating or a secured protective turf overlay on cuts and fill batters to minimise erosion;

Where a capping layer of topsoil, sandy material or crushed rock cannot be placed to reduce the potential for dispersive behaviour of the highly sodic soils, and where vegetation cover is not adequate to control erosion, consideration should be given to mixing of gypsum into soil or filling and placement on exposed slopes to improve soil structure and reduce the potential for scour. The concentrations of gypsum added should be determined by site specific testing;

Maintenance including watering of lands established with grass cover until an effective cover has been established. Where there has been inadequate vegetation establishment, further application of seed should be carried out. During establishment, trafficking of the treated areas should be minimised.

The management strategies listed above essentially comprise a range of common-sense and effective earthworks controls that would typically be adopted by any competent earthworks contractor. To provide tighter control on such strategies, contractors should be provided with additional guidance through the preparation of appropriate project construction documentation and specifications, for which these would be considered largely cost saving measures, rather than additional project cost items. 14.6 Geotechnical Considerations

14.6.1 Site Classification

Classification of individual lots or residential building areas within the site should comply with the requirements of AS 2870 – 2011 "Residential Slabs and Footings" (Ref 5). Based on the limited work for the current investigation, the undisturbed subsurface profiles at most locations are typical of Class M (moderately reactive) and Class H (highly reactive) sites. Further delineation between Class H1 and Class H2 sites would need to be made for any subsequent construction certificate issue or prior to linen release. Laboratory shrink swell index tests have returned low and moderately high values, indicating potential extremes in the shrink swell potential across the site. The current results of Atterberg limits testing are considered more representative of the soils observed in the test pits. Prior to development construction, lot classification ranges should be clarified and specific classifications should be made for each new residential site. The exception to the above would be where existing filling, such as that within the existing dam walls, warranted an alternative classification of Class P. However, the construction of residences is unlikely to occur close to these dams, as they will probably be removed during subdivision construction. Similarly, placement of filling during subdivisional earthworks may alter the classification of site areas

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affected by controlled filling, although with appropriate consideration during design, filled lots could be maintained as Class M or Class H sites. In addition, future coal or other mining leases that affect the site will result in the forced issuing of Class P classifications for all new lots due to the probable future effects of mine subsidence. This potential affects all new lots within the study area. The design of new structures on sites affected by mine subsidence requires particular structural design consideration and the assistance of the mine subsidence board to provide recommendations to designers on appropriate design parameters, such as settlement, curvature tilt, and horizontal strain. DP understands that the effects of mine subsidence are being considered by Mine Subsidence Engineering Consultants (MSEC).

14.6.2 Footings

All footing systems should be designed and constructed in accordance with AS2870-2011 (Ref 5) for the appropriate site classification. High level footing systems founding on stiff to very stiff clay soil would be appropriate for Class M and Class H sites (most new lots). Further delineation between Class H1 and Class H2 sites would need to be made for any subsequent construction certificate issue or prior to linen release. In addition, foundation systems may be required for Class S or Class A sites (a small proportion of the overall number of lots), subject to rock depths and the depth of excavation undertaken during individual residence construction, particularly in the outer edges of the site where rock depths are generally shallow. It is pointed out though that Class S and Class A sites are difficult to achieve, when dealing with clay soils. Whilst conventional high level footing systems would be appropriate for Class M or Class H sites, suitable foundation systems for Class P lots could include (depending on the depth of suitable founding stratum, the presence of groundwater and Mine Subsidence Board requirements) backhoe excavated blockdowns, pier and beam, screw piles or possible driven timber piles and mini piles founding on the underlying stiff clays or weathered rock. For hillside construction, reference should be made to the Australian Geomechanics Society (AGS) publication Practice Note on Landslide Risk Management (Ref 9), relevant Australian Geoguides LR1 to LR9 are included in Appendix G. The principal recommendation for hillside development is for footings to found below the zone of potential soil movement and within the underlying weathered rock. Footings for all other structures should be based on the results of specific geotechnical investigations. As a guide, preliminary design could be based on maximum allowable bearing pressures of 150 kPa for stiff to very stiff clays and 800 kPa for highly weathered rock of at least very low strength.

14.6.3 Site Preparation and Earthworks

Site preparation for the construction of structures and pavements should include the removal of topsoils and other deleterious materials from the proposed building areas. In areas that require filling, the stripped surfaces should be proof rolled in the presence of a geotechnical engineer. Any areas exhibiting significant deflections under proof rolling should be appropriately treated by over-excavation and replacement with low plasticity filling placed in near horizontal layers no thicker than 250 mm compacted thickness. Each layer should be compacted to a minimum dry density ratio of 98%, relative to Standard compaction with placement moisture contents

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maintained within 2% of standard optimum. The upper 0.5 m in areas of pavement construction should achieve a minimum dry density ratio of 100% relative to Standard compaction with placement moisture contents similarly maintained. All batters should be constructed no steeper than 3H:1V and appropriately vegetated to reduce the effects of erosion. Batters should be flattened to 4H:1V in areas affected by soils of the Luddenham soil landscape, unless appropriate erosion protection can be proven and adequately maintained. To validate site classifications, sufficient field inspections and in situ testing of future earthworks should be undertaken in order to satisfy the requirements of a Level 1 inspection and testing service as defined in AS3798-2007 “Guidelines on Earthworks for Commercial and Residential Developments” (Ref 10). This is a standard requirement of Wollondilly Shire Council. Earthworks required for pavement construction will need to be based on batters formed no steeper than 3H:1V in the residual clays. All batters should be suitably protected against erosion with toe and spoon drains constructed as a means of controlling surface flows on the batters. Within hillside lots (i.e. those on steeper ground surface slopes), excavation and filling should generally be limited to a maximum vertical height of 1 m respectively below or above the existing ground surface. Proposed earthworks that exceed the above requirements should be subject to review by a geotechnical engineer during the design phase of the individual project. Excavations that exceed 1 m must be supported by engineer-designed retaining walls founded on bedrock. However, it must be accepted that creep movement in retaining walls constructed perpendicular to the slope is probably inevitable, due to the high active pressures of the retained material. If embankments are proposed for use as water quality control ponds, then the results of testing completed to date indicates that the site soils may be suitable for re-use as embankment materials, subject to further consideration of sodicity and erosion. Subject to the detailed design, detention basins (i.e.: short term storage only) could be dimensioned with maximum batter slopes of 4H:1V, with allowance made for accommodating the results of erosion (such as topsoiling and turfing) if soils with an ECN of less than 4 be proposed for use. Subject to design permeability requirements, the use of liners on both the embankments and within parts of the reservoir area may also be necessary. Site observations have indicated the presence of silty topsoils and silty clays which could be adversely affected by inclement weather. Whilst these soils are typically of a stiff to very stiff consistency when dry, they can rapidly lose strength during rainfall and subsequent partial saturation, and result in difficult traffickability conditions. As a result, surface drainage that directs runoff away from work areas should be installed prior to construction, possibly in conjunction with the designation of construction equipment haul routes to minimise trafficking of stripped areas. Conventional sediment and erosion control measures should be implemented during the construction phase, with exposed surfaces to be topsoiled and vegetated as soon as practicable following the completion of earthworks.

14.6.4 Site Maintenance and Drainage

The developed lots should be maintained in accordance with the CSIRO publication "Guide to Home Owners on Foundation Maintenance and Footing Performance", a copy of which is included in

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Appendix G. Whilst it must be accepted that minor cracking in most structures is inevitable, the guide describes suggested site maintenance practices aimed at minimising foundation movement to keep cracking within acceptable limits. Adequate surface drainage should be installed and maintained at the site. All collected stormwater, groundwater and roof runoff should be discharged into the stormwater disposal system. Similarly, effluent flows should be directed to the sewerage system. .

14.6.5 Pavements

Whilst detailed design of pavements will be undertaken at the development application stage, a range of pavement thickness designs (excluding asphalt thicknesses) is shown in Table 5. These designs are based on the procedures given in AUSTROADS Guide to Pavement Technology Part 2: Pavement Structural Design, Figure 8.4 (Ref 11) for a range of traffic loadings and subgrade CBR values and are provided to give an indication of the range of pavement thickness that can be expected. Wollondilly Shire Council may require slightly thicker pavements, where the following thicknesses are less than Council’s minimum pavement construction thickness. Table 5: Preliminary Pavement Thickness Designs

Traffic Loading (ESA)

Total Pavement Thickness Excluding Asphalt (mm)

CBR 3% CBR 4% CBR 5% CBR 7%

1 x 105 380 330 290 240

3 x 105 440 380 340 280

1 x 106 520 440 390 320 The pavements should be placed and compacted in layers no thicker than 200 mm with control exercised over placement moisture contents. If layer thicknesses greater than 200 mm are proposed, then it may be necessary to test the top and bottom of the layer to ensure that the minimum level of compaction has been achieved through the layer. Suggested material quality and compaction requirements are given in Table 6 (following page). Whilst the use of lesser quality pavement materials than that detailed in Table 6 (following page) may be feasible, some compromise in either performance and/or pavement life must be anticipated and accepted. It is also suggested that advice be sought from Council if lesser quality pavement materials are proposed. Surface and subsoil drainage should be installed and maintained to protect the pavement and subgrade. The subsoil drains should be located at a minimum of 0.6 m depth below the pavement subgrade with drains placed on the high sides of all pavements, as a minimum. Guidelines on the arrangement of subsoil drains are given on Page 20 of ARRB-SR41 (Ref 12).

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Table 6: Suggested Materials and Compaction Requirements

Layer Material Quality Minimum Compaction

Wearing Course To conform to Council requirements Generally AC10/AC14 asphalt To conform to Council requirements

Base Course To conform to RTA3051 for DGB20 Soaked CBR 80%, PI 6% or Council requirements

Minimum dry density ratio of 98% Modified (AS1289.5.2.1)

Sub-base Course To conform to RTA3051 for DGS20 Soaked CBR 30%, PI 12% or Council requirements

Minimum dry density ratio of 98% Modified (AS1289.5.2.1)

Subgrade Minimum dry density ratio of 100% Standard (AS1289.5.1.1)

Note: PI = Plasticity Index Where weak, water-logged soils are encountered (for example, in the vicinity of gullies or downstream of existing dams), the inclusion of a 500 mm thick granular bridging layer (possibly in conjunction with geotextiles) may be required. 14.7 Soil and Water Management Plan

Based on the results of the current site assessment, the implementation of a soil and water management plan (SWMP) for this development is not essential, as assessment results indicate non-saline and generally non-aggressive to mildly aggressive soil conditions. However, it may be prudent to develop a SWMP to ensure appropriate site design given that the sodicity and erosion potential is moderate to very high. A common sense approach to the control of ground surfaces, by maintaining constant vegetation or limiting the time of exposure for stripped ground, should be sufficient to maintain the integrity of the site. Further testing is recommended for soil and surface water salinity prior to development application approval. Hence, a SWMP can be developed and implemented then, if the results of these works show a plan is necessary. If adopted, the scope of the plan could also be expanded to cater for controls on minimising soil erosion and maximising the re-use of existing site materials, together with providing guidance for implementation controls, land disturbance, pollution control and construction inspections and maintenance during development. The following provides a conceptual SWMP with the objectives of controlling site works:

General Instructions: These conditions include methods to ensure compliance with the SWMP, specifically:

The SWMP will be read with the engineering plans and site specific instructions issued in relation to the development;

Contractors will ensure that all soil and water management works are undertaken as instructed in the specification and constructed in accordance with AS 3798 - 2007 (Ref. 10);

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All subcontractors will be informed by the Superintendent of their responsibilities in minimising the potential for soil erosion and pollution of downslope areas.

Land Disturbance: These conditions provide methods to minimise soil erosion, the exposure of potentially or known saline subsoils and direction of overland drainage into areas of potential slope instability, specifically:

The erosion hazard will be kept as low as possible by limiting of construction area size at any one time and clearly defining the area by barrier fencing upslope and sediment fencing downslope (to be installed before the commencement of construction activities);

Access areas will be clearly defined and limited in size while being considerate of the needs of efficient work areas. All site workers will clearly recognise these boundaries;

The prohibition of entry into areas outside physical works except for essential management works;

Restriction of work in creek lines during periods of rainfall, with programming of works in these areas to be within periods of anticipated lower rainfall;

The programming of development road works and major excavations to minimise the time of soil exposure and to coincide with periods of anticipated lower rainfall;

Placement of topsoils and subsoils in separate stockpiles (where required) with appropriate sediment fencing and dimensions selected to minimise the surface area of soils exposed to rainfall and hence erosion and leaching of saline materials;

The creation of larger lots on steeper slope sections to permit the more sensitive development of the individual site;

Orientation of access roads and services to minimise the requirements of excavation and possible retaining structures;

Where excavation or filling of batters is required, the construction of these at as low as practical gradient with a maximum 3:1 (H:V) in the clay soil profiles;

The placement of excavated soils in filled areas in the sequence of excavation (i.e. to place potentially saline or sodic subsoils below a capping of non-saline material);

During windy conditions, large, unprotected areas will be kept moist by sprinkling with water to keep dust under control. In the event that water is not available in sufficient quantities, soil binders and/or retardants will be used or the surface will be left in a cloddy state that resists removal by wind;

The inclusion of techniques, such as spray coating or a secured protective turf overlay on cut and fill batters to minimise erosion;

The maximisation and/or replacement of native tree cover and deep-rooted plants, particularly in areas of known or potential slope instability;

Where vegetation cover is not adequate to control erosion, the improvement of soil resistance to erosion by the addition of lime and gypsum (the proportion to be determined by site specific testing);

Maintenance including watering of lands established with grass cover until an effective cover has been established. Where there has been inadequate vegetation establishment, further

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application of seed should be carried out. During establishment, trafficking of the treated areas should be minimised;

The design of stormwater drainage, including lined catch drains at the crest of cut slopes, stormwater pipes and dissipators as required to minimise concentrated runoff and to provide controlled discharge of the collected runoff;

The sampling and analysis of groundwater samples from monitoring bores installed prior to construction in order to assess impacts on groundwater quality.

Pollution Control: These conditions provide measures to protect downstream areas for water-borne pollution, specifically:

The installation of sediment fences to contain the coarser sediment fraction as near as possible to their source;

Ensuring that stockpiles are not located within hazard areas, including areas of likely high velocity flow, such as waterways, paved areas and driveways;

The installation of sediment basins downslope of areas to be disturbed, with the design based upon a design storm event;

The inclusion of one or more pegs in the floor of the sediment basins to indicate the level at which design capacity occurs and when collected sediment will be removed;

Disposal of trapped materials from sediment basins to locations where further erosion and consequent pollution to downslope lands and waterways will not occur;

Sampling and laboratory analysis of collected waters to ensure compliance with benchmark parameters prior to discharge;

The treatment of collected waters by gypsum and settling of flocculated particles before any discharge occurs (unless the design storm event is exceeded);

The removal of sediment basins (where not required as part of the on-going site management) only after the lands they are protecting are stabilised.

Site Inspection and Maintenance: These conditions provide for self and external auditing of the performance of construction and pollution protection measures, together with appropriate maintenance of erosion and sedimentation structures, specifically:

A self-auditing program against an established checklist to be completed by the site manager at least weekly, immediately before site closure and immediately following rainfall events in excess of 5 mm in any one 24 hour period. The audit should include the recording of the condition of temporary sediment and water control devices, any maintenance requirements for these structures, volumes and disposal sites of material removed from sediment retention systems. A copy of the audit should be provided to the project Superintendent;

Provision for periodic inspection of records and site conditions by an external, suitably qualified person, for oversight of soil and water management works. The person will be responsible for ensuring that the SWMP is being implemented correctly, repairs are being undertaken as required and modifications to the SWMP are made if and when necessary. A short written report will be provided at appropriate intervals and will confirm that the works have been carried out according to the approved plans.

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14.8 Agricultural Potential

As part of the land capability assessment, DP engaged Harvest as a sub-consultant to undertake an assessment of the agricultural potential of the Wilton Junction study area. A copy of the draft Harvest report Agricultural Land Capability Study for the Proposed New Wilton Township (Job Ref 201381, dated 30 May 2013) is presented in Appendix H. The assessment of agricultural potential is essentially undertaken in two parts, including:

Part 1 – an agricultural land capability assessment to determine if the proposed development will result in a loss of current or potential valuable agricultural land, whether the land should be reserved for future agricultural development, or if the land is constrained and thus not suitable for agricultural use; and

Part 2 – a land use conflict risk assessment to determine actual and potential land use conflicts arising from site development, including those of surrounding properties.

In essence, Part 1 of the assessment process aims to protect Class 1, 2, 3 and Specialist Class land areas. Having completed Part 1 of the assessment process, Harvest determined:

No Class 1, 2 or Specialist Class land was identified;

Approximately 620 hectares of Class 3 land was identified, although Class 3 lands were constrained by:

- Poor soil fertility;

- Erodibility issues;

- Access to fresh water for irrigation;

- The presence of threatened ecological communities;

- Limited existing agricultural infrastructure, other than for grazing; and

- Existing infrastructure that is antiquated, or needs refurbishment or replacement. Harvest concluded that the Wilton Junction site is essentially already developed to near-capacity. Therefore, the loss of future agricultural land potential is limited. Part 2 of the assessment process aims to identify any land use conflicts and risks of occurrence before a new land use proceeds. In addition, the process assesses the effect of a proposed land use on existing neighbouring land uses to guide the establishment of complementary development controls and buffer requirements and to develop strategies to minimise potential land use conflicts to assist negotiation, proposal, implementation and evaluation of separation strategies. Having completed Part 2 of the assessment process, Harvest concluded that land use conflicts may arise, specifically due to noise, dust, erosion, domestic pets, trespass, visual amenity and traffic. The highest risk ratings were deemed attributable to erosion, domestic pets, visual amenity and traffic, thus careful consideration is required during project design.

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15. Further Investigation

The results of the land capability assessment to date have not identified any issue that would preclude the rezoning of the Wilton Junction site for urban development. Further investigation will, however, be required as the project progresses to development application. Additional work will also be required during the project’s construction phase. Specific investigation would typically be undertaken at the appropriate development application or construction certificate stage and would include (but not necessarily be limited to):

Additional salinity investigations for site soils and surface waters (i.e. dams) to increase the density of the data obtained to date. The investigation programme should be increased to compliment the current study and augment the findings to a frequency of testing satisfying one test pit location per one to two hectares, including additional full depth profile sampling and laboratory analysis. A cost effective way of conducting the salinity assessment would be to measure site conductivity using an electro-magnetic (EM) transceiver mounted to an all-terrain vehicle (ATV or quad-bike), thus reducing the number of test pits required for the assessment. This method would also significantly increase the number of conductivity readings measured and thus provide greater coverage of the site.

Additional investigation should be undertaken in development areas which are to be excavated deeper than 2 m or into rock at shallower depth, where direct sampling and testing of salinity has not been carried out. Salinity management strategies should then be reassessed following additional investigation by deep test pitting and/or drilling, sampling and testing for soil and water pH, electrical conductivity, TDS, sodicity, sulphates and chlorides.

Additional testing of the site’s soils and surface water (and groundwater, if encountered) for aggressivity testing and its effects on buried concrete and steel structures.

Additional testing of site soils for erosion and dispersion properties to provide better guidance on the design and construction of future water bodies and the ability of the soils to be used as clay liners, or similar.

Detailed geotechnical investigations on a stage-by-stage basis for determination of pavement thickness designs and lot classifications, as well as stage specific issues, such as deep excavations and construction of roads and dwellings/structures on steeper landforms and crests.

Routine inspections and earthworks monitoring during construction. For further details of the type of works likely to be required during subsequent project works, refer to the project works undertaken for the Bingara Gorge development, as listed in Section 5.1. 16. Summary of Land Capability for Site Development

Based on the results of the assessment thus far, the following summary points are noted:

No evidence of hillside/slope instability was observed within the proposed net developable area. It is considered that such instability does not impose significant constraints on the proposed site development under the current Master plan.

The presence of erosive soils on site should not present significant constraints to development provided they are well managed during earthworks and site preparation stages.

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No significant evidence of saline soil was identified within the site. Although further salinity testing is considered necessary, at this stage salinity levels are sufficiently low for this site to be deemed free of significant salinity constraints.

Although mild aggressivity to concrete is regularly encountered across the site, aggressivity levels are considered to be manageable, subject to appropriate design and construction consideration.

Highly sodic and sodic soils appear widespread and will require management to reduce dispersion, erosion and to improve drainage.

The results of the land capability assessment have not identified any issue that would preclude the rezoning of the Wilton Junction site for urban development.

17. Limitations

Douglas Partners (DP) has prepared this report for this project at Wilton Junction, Wilton, NSW, in accordance with DP’s proposal SYD130344 and acceptance received from Mr Brian Elton of Elton Consulting Pty Ltd, client’s representative on 3 May 2013. The work was carried out under the terms of the contract agreement between DP and our client, collectively Bradcorp Wilton Pty Ltd, Governors Hill and Walker Corporation Pty Ltd. The report is provided for the exclusive use of Elton Consulting Pty Ltd and the collective client for this project only and for the purposes as described in the report. It should not be used by or relied upon for other projects or purposes on the same or other site or by a third party. Any party so relying upon this report beyond its exclusive use and purpose as stated above, and without the express written consent of DP, does so entirely at its own risk and without recourse to DP for any loss or damage. In preparing this report DP has necessarily relied upon information provided by the client and/or their agents. The results provided in the report are indicative of the sub-surface conditions on the site only at the specific sampling and/or testing locations, and then only to the depths investigated and at the time the work was carried out. Sub-surface conditions can change abruptly due to variable geological processes and also as a result of human influences. Such changes may occur after DP’s field testing has been completed. DP’s advice is based upon the conditions encountered during this investigation. The accuracy of the advice provided by DP in this report may be affected by undetected variations in ground conditions across the site between and beyond the sampling and/or testing locations. The advice may also be limited by budget constraints imposed by others or by site accessibility. This report must be read in conjunction with all of the attached and should be kept in its entirety without separation of individual pages or sections. DP cannot be held responsible for interpretations or conclusions made by others unless they are supported by an expressed statement, interpretation, outcome or conclusion stated in this report. This report, or sections from this report, should not be used as part of a specification for a project, without review and agreement by DP. This is because this report has been written as advice and opinion rather than instructions for construction.

of 39


The contents of this report do not constitute formal design components such as are required, by the Health and Safety Legislation and Regulations, to be included in a Safety Report specifying the hazards likely to be encountered during construction and the controls required to mitigate risk. This design process requires risk assessment to be undertaken, with such assessment being dependent upon factors relating to likelihood of occurrence and consequences of damage to property and to life. This, in turn, requires project data and analysis presently beyond the knowledge and project role respectively of DP. DP may be able, however, to assist the client in carrying out a risk assessment of potential hazards contained in the Comments section of this report, as an extension to the current scope of works, if so requested, and provided that suitable additional information is made available to DP. Any such risk assessment would, however, be necessarily restricted to the geotechnical components set out in this report and to their application by the project designers to project design, construction, maintenance and demolition.

Douglas Partners Pty Ltd References

1. Geology of Wollongong-Port Hacking 1:100 000 Sheet, New South Wales Geological Survey, Sydney.

2. Soil Landscapes of Wollongong-Port Hacking 1:100 000 Sheet, Soil Conservation Service of New South Wales.

3. McNally, G. 2005. Investigation of urban salinity – case studies from western Sydney. UrbanSalt 2005 Conference Paper, Parramatta.

4. DECC, 2008. Salinity Potential of the Hawkesbury Nepean Catchment 1:100 000 Sheet. Department of Environment and Climate Change, New South Wales.

5. Standards Australia. 2011. AS2870-2011 Residential Slabs and Footings.

6. Richards, L. A. (ed.) 1954. Diagnosis and Improvement of Saline and Alkaline Soils. USDA Handbook No. 60, Washington D.C.

7. Hazelton, P. A. and Murphy B. W. 1992. A Guide to the Interpretation of Soil Test Results. Department of Conservation and Land Management.

8. Standards Australia. 2009. AS2159-2009 Piling – Design and Installation.

9. Australian Geomechanics Society (AGS). Practice Note on Landslide Risk Management, 2007.

10. Standards Australia. 2007. AS3798-2007 Guidelines on Earthworks for Commercial and Residential Developments.

11. AUSTROADS Guide to Pavement Technology Part 2: Pavement Structural Design.

12. Australian Roads Research Board – Special Report 41, 1989. A Structural Design Guide for Residential Street Pavements.

Appendix A

About this Report

July 2010

Introduction These notes have been provided to amplify DP's report in regard to classification methods, field procedures and the comments section. Not all are necessarily relevant to all reports.

DP's reports are based on information gained from limited subsurface excavations and sampling, supplemented by knowledge of local geology and experience. For this reason, they must be regarded as interpretive rather than factual documents, limited to some extent by the scope of information on which they rely.

Copyright This report is the property of Douglas Partners Pty Ltd. The report may only be used for the purpose for which it was commissioned and in accordance with the Conditions of Engagement for the commission supplied at the time of proposal. Unauthorised use of this report in any form whatsoever is prohibited.

Borehole and Test Pit Logs The borehole and test pit logs presented in this report are an engineering and/or geological interpretation of the subsurface conditions, and their reliability will depend to some extent on frequency of sampling and the method of drilling or excavation. Ideally, continuous undisturbed sampling or core drilling will provide the most reliable assessment, but this is not always practicable or possible to justify on economic grounds. In any case the boreholes and test pits represent only a very small sample of the total subsurface profile.

Interpretation of the information and its application to design and construction should therefore take into account the spacing of boreholes or pits, the frequency of sampling, and the possibility of other than 'straight line' variations between the test locations.

Groundwater Where groundwater levels are measured in boreholes there are several potential problems, namely: In low permeability soils groundwater may

enter the hole very slowly or perhaps not at all during the time the hole is left open;

A localised, perched water table may lead to an erroneous indication of the true water table;

Water table levels will vary from time to time with seasons or recent weather changes. They may not be the same at the time of construction as are indicated in the report; and

The use of water or mud as a drilling fluid will mask any groundwater inflow. Water has to be blown out of the hole and drilling mud must first be washed out of the hole if water measurements are to be made.

More reliable measurements can be made by installing standpipes which are read at intervals over several days, or perhaps weeks for low permeability soils. Piezometers, sealed in a particular stratum, may be advisable in low permeability soils or where there may be interference from a perched water table.

Reports The report has been prepared by qualified personnel, is based on the information obtained from field and laboratory testing, and has been undertaken to current engineering standards of interpretation and analysis. Where the report has been prepared for a specific design proposal, the information and interpretation may not be relevant if the design proposal is changed. If this happens, DP will be pleased to review the report and the sufficiency of the investigation work.

Every care is taken with the report as it relates to interpretation of subsurface conditions, discussion of geotechnical and environmental aspects, and recommendations or suggestions for design and construction. However, DP cannot always anticipate or assume responsibility for: Unexpected variations in ground conditions.

The potential for this will depend partly on borehole or pit spacing and sampling frequency;

Changes in policy or interpretations of policy by statutory authorities; or

The actions of contractors responding to commercial pressures.

If these occur, DP will be pleased to assist with investigations or advice to resolve the matter.

July 2010

Site Anomalies In the event that conditions encountered on site during construction appear to vary from those which were expected from the information contained in the report, DP requests that it be immediately notified. Most problems are much more readily resolved when conditions are exposed rather than at some later stage, well after the event.

Information for Contractual Purposes Where information obtained from this report is provided for tendering purposes, it is recommended that all information, including the written report and discussion, be made available. In circumstances where the discussion or comments section is not relevant to the contractual situation, it may be appropriate to prepare a specially edited document. DP would be pleased to assist in this regard and/or to make additional report copies available for contract purposes at a nominal charge.

Site Inspection The company will always be pleased to provide engineering inspection services for geotechnical and environmental aspects of work to which this report is related. This could range from a site visit to confirm that conditions exposed are as expected, to full time engineering presence on site.

Appendix B

Drawings 1 to 5

DATE:

SCALE:

DRAWN BY:

OFFICE:TITLE:

REVISION:DRAWING No:PROJECT No:CLIENT:

Sydney

AT

4.06.2014

1:30,000 @ A3B173467.00Wilton Land Owners Group

MGA

DATE:

SCALE:

DRAWN BY:

OFFICE:TITLE:


Sydney

AT

4.06.2014


MGA

Appendix C

Site Photographs – Photos 1 to 31

Wilton Junction PROJECT: 73467

Land Capability Assessment PLATE No: 1

Hume Hwy & Picton Rd, Wilton REV:

CLIENT: Wilton Junction Landowners Group DATE: 9-Jul-13

Photo 2 - View across Walker Corporation land

Photo 1 - View along southern boundary of Walker Corporation land





Photo 4 - View of boundary of Bradcorp and Governors Hill lands

Photo 3 - View across Governors Hill land





Photo 5 - View across south west part of Bradcorp land

Photo 6 - View across west part of Bradcorp land





Photo 7 - View across north east part of Bradcorp land

Photo 8 - View across north west part of Bradcorp land





Photo 9 - Erosion on north face of crest within southern part of Governors Hill land

Photo 10 - Erosion on north face of crest near southern boundary of Walker Corporation land






Photo 16 - Erosion on north west face of crest near central part of Bradcorp land





Photo 18 - Erosion in broad shallow gully near central part of Bradcorp land

Photo 17 - Erosion on north west face of crest near central part of Bradcorp land





Photo 21 - Rock outcrops evident in shallow gullies at south west part of Walker Corporation land

Photo 22 - Rock outcrops evident in shallow gullies at south east part of Governors Hill land





Photo 23 - Rock outcrops evident in shallow gullies at south east part of Governors Hill land

Photo 24 - Typical rock outcrop evident across surface of western part of Bradcorp land





Photo 25 - Rockfall instability at western edge of Bradcorp land outside of proposed developable area





Photo 26 - Vegetation change near southern boundary of Walker Corporation land

Photo 27 - Vegetation change near southern boundary of Walker Corporation land





Photo 28 - Vegetation change near crest in central part of Bradcorp land (soil landscape change)

Photo 29 - Vegetation change near western endge of Bradcorp land





Photo 31 - Near-full dam at northern side of Bradcorp land (typical of all dams at site)

Photo 30 - Near-full dam at western side of Bradcorp land (typical of all dams at site)

Appendix D

Field Work Results – TP1 to TP45

July 2010

SamplingSampling is carried out during drilling or test pitting to allow engineering examination (and laboratory testing where required) of the soil or rock.

Disturbed samples taken during drilling provide information on colour, type, inclusions and, depending upon the degree of disturbance, some information on strength and structure.

Undisturbed samples are taken by pushing a thin-walled sample tube into the soil and withdrawing it to obtain a sample of the soil in a relatively undisturbed state. Such samples yield information on structure and strength, and are necessary for laboratory determination of shear strength and compressibility. Undisturbed sampling is generally effective only in cohesive soils.

Test Pits Test pits are usually excavated with a backhoe or an excavator, allowing close examination of the in-situ soil if it is safe to enter into the pit. The depth of excavation is limited to about 3 m for a backhoe and up to 6 m for a large excavator. A potential disadvantage of this investigation method is the larger area of disturbance to the site.

Large Diameter Augers Boreholes can be drilled using a rotating plate or short spiral auger, generally 300 mm or larger in diameter commonly mounted on a standard piling rig. The cuttings are returned to the surface at intervals (generally not more than 0.5 m) and are disturbed but usually unchanged in moisture content. Identification of soil strata is generally much more reliable than with continuous spiral flight augers, and is usually supplemented by occasional undisturbed tube samples.

Continuous Spiral Flight Augers The borehole is advanced using 90-115 mm diameter continuous spiral flight augers which are withdrawn at intervals to allow sampling or in-situ testing. This is a relatively economical means of drilling in clays and sands above the water table. Samples are returned to the surface, or may be collected after withdrawal of the auger flights, but they are disturbed and may be mixed with soils from the sides of the hole. Information from the drilling (as distinct from specific sampling by SPTs or undisturbed samples) is of relatively low

reliability, due to the remoulding, possible mixing or softening of samples by groundwater.

Non-core Rotary Drilling The borehole is advanced using a rotary bit, with water or drilling mud being pumped down the drill rods and returned up the annulus, carrying the drill cuttings. Only major changes in stratification can be determined from the cuttings, together with some information from the rate of penetration. Where drilling mud is used this can mask the cuttings and reliable identification is only possible from separate sampling such as SPTs.

Continuous Core Drilling A continuous core sample can be obtained using a diamond tipped core barrel, usually with a 50 mm internal diameter. Provided full core recovery is achieved (which is not always possible in weak rocks and granular soils), this technique provides a very reliable method of investigation.

Standard Penetration Tests Standard penetration tests (SPT) are used as a means of estimating the density or strength of soils and also of obtaining a relatively undisturbed sample. The test procedure is described in Australian Standard 1289, Methods of Testing Soils for Engineering Purposes - Test 6.3.1.

The test is carried out in a borehole by driving a 50 mm diameter split sample tube under the impact of a 63 kg hammer with a free fall of 760 mm. It is normal for the tube to be driven in three successive 150 mm increments and the 'N' value is taken as the number of blows for the last 300 mm. In dense sands, very hard clays or weak rock, the full 450 mm penetration may not be practicable and the test is discontinued.

The test results are reported in the following form. In the case where full penetration is obtained

with successive blow counts for each 150 mm of, say, 4, 6 and 7 as:

4,6,7N=13

In the case where the test is discontinued before the full penetration depth, say after 15 blows for the first 150 mm and 30 blows for the next 40 mm as:

15, 30/40 mm

July 2010

The results of the SPT tests can be related empirically to the engineering properties of the soils.

Dynamic Cone Penetrometer Tests / Perth Sand Penetrometer Tests Dynamic penetrometer tests (DCP or PSP) are carried out by driving a steel rod into the ground using a standard weight of hammer falling a specified distance. As the rod penetrates the soil the number of blows required to penetrate each successive 150 mm depth are recorded. Normally there is a depth limitation of 1.2 m, but this may be extended in certain conditions by the use of extension rods. Two types of penetrometer are commonly used. Perth sand penetrometer - a 16 mm diameter

flat ended rod is driven using a 9 kg hammer dropping 600 mm (AS 1289, Test 6.3.3). This test was developed for testing the density of sands and is mainly used in granular soils and filling.

Cone penetrometer - a 16 mm diameter rod with a 20 mm diameter cone end is driven using a 9 kg hammer dropping 510 mm (AS 1289, Test 6.3.2). This test was developed initially for pavement subgrade investigations, and correlations of the test results with California Bearing Ratio have been published by various road authorities.

July 2010

Description and Classification Methods The methods of description and classification of soils and rocks used in this report are based on Australian Standard AS 1726, Geotechnical Site Investigations Code. In general, the descriptions include strength or density, colour, structure, soil or rock type and inclusions.

Soil Types Soil types are described according to the predominant particle size, qualified by the grading of other particles present:

Type Particle size (mm) Boulder >200 Cobble 63 - 200 Gravel 2.36 - 63 Sand 0.075 - 2.36 Silt 0.002 - 0.075 Clay <0.002

The sand and gravel sizes can be further subdivided as follows:

Type Particle size (mm) Coarse gravel 20 - 63 Medium gravel 6 - 20 Fine gravel 2.36 - 6 Coarse sand 0.6 - 2.36 Medium sand 0.2 - 0.6 Fine sand 0.075 - 0.2

The proportions of secondary constituents of soils are described as:

Term Proportion Example And Specify Clay (60%) and

Sand (40%) Adjective 20 - 35% Sandy Clay Slightly 12 - 20% Slightly Sandy

Clay With some 5 - 12% Clay with some

sandWith a trace of 0 - 5% Clay with a trace

of sand

Definitions of grading terms used are: Well graded - a good representation of all

particle sizes Poorly graded - an excess or deficiency of

particular sizes within the specified range Uniformly graded - an excess of a particular

particle size Gap graded - a deficiency of a particular

particle size with the range

Cohesive Soils Cohesive soils, such as clays, are classified on the basis of undrained shear strength. The strength may be measured by laboratory testing, or estimated by field tests or engineering examination. The strength terms are defined as follows:

Description Abbreviation Undrained shear strength

(kPa)Very soft vs <12Soft s 12 - 25 Firm f 25 - 50 Stiff st 50 - 100 Very stiff vst 100 - 200 Hard h >200

Cohesionless Soils Cohesionless soils, such as clean sands, are classified on the basis of relative density, generally from the results of standard penetration tests (SPT), cone penetration tests (CPT) or dynamic penetrometers (PSP). The relative density terms are given below:

Relative Density

Abbreviation SPT N value

CPT qc value(MPa)

Very loose vl <4 <2 Loose l 4 - 10 2 -5 Medium dense

md 10 - 30 5 - 15

Dense d 30 - 50 15 - 25 Very dense

vd >50 >25

July 2010

Soil Origin It is often difficult to accurately determine the origin of a soil. Soils can generally be classified as: Residual soil - derived from in-situ weathering

of the underlying rock; Transported soils - formed somewhere else

and transported by nature to the site; or Filling - moved by man.

Transported soils may be further subdivided into: Alluvium - river deposits Lacustrine - lake deposits Aeolian - wind deposits Littoral - beach deposits Estuarine - tidal river deposits Talus - scree or coarse colluvium Slopewash or Colluvium - transported

downslope by gravity assisted by water. Often includes angular rock fragments and boulders.

July 2010

Rock Strength Rock strength is defined by the Point Load Strength Index (Is(50)) and refers to the strength of the rock substance and not the strength of the overall rock mass, which may be considerably weaker due to defects. The test procedure is described by Australian Standard 4133.4.1 - 1993. The terms used to describe rock strength are as follows:

Term Abbreviation Point Load Index Is(50) MPa

Approx Unconfined Compressive Strength MPa*

Extremely low EL <0.03 <0.6

Very low VL 0.03 - 0.1 0.6 - 2

Low L 0.1 - 0.3 2 - 6

Medium M 0.3 - 1.0 6 - 20

High H 1 - 3 20 - 60

Very high VH 3 - 10 60 - 200

Extremely high EH >10 >200 * Assumes a ratio of 20:1 for UCS to Is(50)

Degree of Weathering The degree of weathering of rock is classified as follows:

Term Abbreviation Description Extremely weathered EW Rock substance has soil properties, i.e. it can be remoulded

and classified as a soil but the texture of the original rock is still evident.

Highly weathered HW Limonite staining or bleaching affects whole of rock substance and other signs of decomposition are evident. Porosity and strength may be altered as a result of iron leaching or deposition. Colour and strength of original fresh rock is not recognisable

Moderately weathered

MW Staining and discolouration of rock substance has taken place

Slightly weathered SW Rock substance is slightly discoloured but shows little or no change of strength from fresh rock

Fresh stained Fs Rock substance unaffected by weathering but staining visible along defects

Fresh Fr No signs of decomposition or staining

Degree of Fracturing The following classification applies to the spacing of natural fractures in diamond drill cores. It includes bedding plane partings, joints and other defects, but excludes drilling breaks.

Term Description Fragmented Fragments of <20 mm Highly Fractured Core lengths of 20-40 mm with some fragments Fractured Core lengths of 40-200 mm with some shorter and longer sections Slightly Fractured Core lengths of 200-1000 mm with some shorter and loner sections Unbroken Core lengths mostly > 1000 mm

July 2010

Rock Quality Designation The quality of the cored rock can be measured using the Rock Quality Designation (RQD) index, defined as:

RQD % = cumulative length of 'sound' core sections 100 mm long total drilled length of section being assessed

where 'sound' rock is assessed to be rock of low strength or better. The RQD applies only to natural fractures. If the core is broken by drilling or handling (i.e. drilling breaks) then the broken pieces are fitted back together and are not included in the calculation of RQD.

Stratification Spacing For sedimentary rocks the following terms may be used to describe the spacing of bedding partings:

Term Separation of Stratification Planes Thinly laminated < 6 mm Laminated 6 mm to 20 mm Very thinly bedded 20 mm to 60 mm Thinly bedded 60 mm to 0.2 m Medium bedded 0.2 m to 0.6 m Thickly bedded 0.6 m to 2 m Very thickly bedded > 2 m

July 2010

Introduction These notes summarise abbreviations commonly used on borehole logs and test pit reports.

Drilling or Excavation Methods C Core Drilling R Rotary drilling SFA Spiral flight augers NMLC Diamond core - 52 mm dia NQ Diamond core - 47 mm dia HQ Diamond core - 63 mm dia PQ Diamond core - 81 mm dia

Water Water seep Water level

Sampling and Testing A Auger sample B Bulk sample D Disturbed sample E Environmental sample U50 Undisturbed tube sample (50mm) W Water sample pp pocket penetrometer (kPa) PID Photo ionisation detector PL Point load strength Is(50) MPa S Standard Penetration Test V Shear vane (kPa)

Description of Defects in Rock The abbreviated descriptions of the defects should be in the following order: Depth, Type, Orientation, Coating, Shape, Roughness and Other. Drilling and handling breaks are not usually included on the logs.

Defect Type B Bedding plane Cs Clay seam Cv Cleavage Cz Crushed zone Ds Decomposed seam F Fault J Joint Lam lamination Pt Parting Sz Sheared Zone V Vein

OrientationThe inclination of defects is always measured from the perpendicular to the core axis.

h horizontal v vertical sh sub-horizontal sv sub-vertical

Coating or Infilling Term cln clean co coating he healed inf infilled stn stained ti tight vn veneer

Coating Descriptor ca calcite cbs carbonaceous cly clay fe iron oxide mn manganese slt silty

Shape cu curved ir irregular pl planar st stepped un undulating

Roughnesspo polished ro rough sl slickensided sm smooth vr very rough

Otherfg fragmented bnd band qtz quartz

July 2010

Graphic Symbols for Soil and Rock

General

Soils

Sedimentary Rocks

Metamorphic Rocks

Igneous Rocks

Road base

Filling

Concrete

Asphalt

Topsoil

Peat

Clay

Conglomeratic sandstone

Conglomerate

Boulder conglomerate

Sandstone

Slate, phyllite, schist

Siltstone

Mudstone, claystone, shale

Coal

Limestone

Porphyry

Cobbles, boulders

Sandy gravel

Laminite

Silty sand

Clayey sand

Silty clay

Sandy clay

Gravelly clay

Shaly clay

Silt

Clayey silt

Sandy silt

Sand

Gravel

Talus

Gneiss

Quartzite

Dolerite, basalt, andesite

Granite

Tuff, breccia

Dacite, epidote

0.2

0.8

1.2

1.4

TOPSOIL - light brown silty clayey topsoil with a trace ofgrass rootlets and ironstone gravel

SANDY CLAY - very stiff light brown and orange brownsilty clay with some sand

SANDY CLAY - very stiff to hard grey red brown/orangesandy clay (extremely weathered sandstone)

SANDSTONE - low to medium strength light brownsandstone

Bore discontinued at 1.4m

Type

133

132

131

130

129

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments

Sampling & In Situ Testing

1

2

3

4

BOREHOLE LOG BOREHOLE LOG BOREHOLE LOG BOREHOLE LOG BOREHOLE LOG BOREHOLE LOG BOREHOLE LOG CLIENT:PROJECT:LOCATION: Hume Highway & Picton Road, Wilton

SAMPLING & IN SITU TESTING LEGENDA Auger sample G Gas sample PID Photo ionisation detector (ppm)B Bulk sample P Piston sample PL(A) Point load axial test Is(50) (MPa)BLK Block sample Ux Tube sample (x mm dia.) PL(D) Point load diametral test Is(50) (MPa)C Core drilling W Water sample pp Pocket penetrometer (kPa)D Disturbed sample Water seep S Standard penetration testE Environmental sample Water level V Shear vane (kPa)

BORE No: 1PROJECT No: 73467DATE: 21/5/2013SHEET 1 OF 1

DRILLER: LOGGED: SB CASING:

Wilton Junction Landowners GroupWilton Junction

REMARKS:

RIG: 8T Backhoe

WATER OBSERVATIONS:TYPE OF BORING:

No free groundwater observed

SURFACE LEVEL: 133 AHDEASTING: 286119NORTHING: 6214688DIP/AZIMUTH: 90°/--

Dynamic Penetrometer Test(blows per 150mm)

5 10 15 20

Sand Penetrometer AS1289.6.3.3 Cone Penetrometer AS1289.6.3.2

D

D

D

D

D

0.1

0.3

0.5

1.0

1.3

0.2

0.6

1.1

2.2

2.4

TOPSOIL - light brown sandy silty topsoil with someironstone gravel and a trace of grass rootlets

SILTY CLAY - very stiff red brown mottled light brown siltyclay

SANDY CLAY - very stiff to hard grey and light brownsandy clay with a trace of rootlets

SANDSTONE - very low strength, extremely weatheredgrey/light brown sandstone

SANDSTONE - low to medium strength grey and orangebrown sandstone

Bore discontinued at 2.4m - backhoe refusal

Type

131

130

129

128

127

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments


1

2

3

4






REMARKS:

RIG: 8T Backhoe




WellConstruction

Details

D

D

D

D

D

0.5

1.0

1.5

2.0

2.3

0.4

1.7

2.1

2.5

TOPSOIL - brown silty topsoil with some clay, grassrootlets and sandstone cobbles

SILTY CLAY - very stiff to hard red brown mottled lightbrown silty clay with a trace of fine ironstone gravel

- from 0.8m: becoming red/brown mottled grey

SANDSTONE - extremely low strength, extremelyweathered, grey and light brown sandstone with somebands of very low to low strength

SANDSTONE - low to medium strength grey/brownsandstone


Type

142

141

140

139

138

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments


1

2

3

4






REMARKS:

RIG: 8T Backhoe




WellConstruction

Details

DB

D

D

D

D

0.4

0.5

0.7

1.0

1.5

2.0

2.4

0.25

0.6

0.8

0.9

TOPSOIL - sandy silty topsoil with some clay and grassrootlets

SANDY CLAY - very stiff orange brown/ red brown sandyclay with a trace of rootlets

SANDSTONE - extremely low strength, extremelyweathered grey brown sandstone

SANDSTONE - medium strength grey brown sandstoneBore discontinued at 0.9m - backhoe refusal

Type

134

133

132

131

130

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments


1

2

3

4






REMARKS:

RIG: 8T Backhoe




WellConstruction

Details

D

D

D

0.1

0.5

0.85

0.1

0.3

0.7

1.2

1.4

TOPSOIL - brown clayey silty topsoil with some sand andgrass rootletsSANDY SILT - light brown and orange brown sandy siltwith some ironstone gravelSILTY CLAY - stiff to very stiff red brown mottled lightbrown silty clay with a trace of rootlets

SANDY CLAY - stiff to very stiff grey/red brown/orangebrown sandy clay (extremely weathered sandstone)

SANDSTONE - low to medium strength brown and greysandstone


Type

140

139

138

137

136

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments


1

2

3

4






REMARKS:

RIG: 8T Backhoe




WellConstruction

Details

D

D

D

0.5

1.0

1.3

0.15

0.7

1.3

TOPSOIL - brown clayey silty topsoil with someironstone gravel and grass rootletsSILTY CLAY - hard red brown mottled light brown siltyclay

SHALE - low strength grey shale

- from 1.0m: medium strength


Type

148

147

146

145

144

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments


1

2

3

4






REMARKS:

RIG: 8T Backhoe





5 10 15 20


D

U50

D

D

0.1

0.2

0.5

1.2

0.25

0.6

0.7

TOPSOIL - brown silty topsoil with some clay and a traceof ironstone gravel and grass rootlets

SANDY CLAY - very stiff orange brown light brown/redbrown sandy clay

SANDSTONE - medium strength grey brown sandstoneBore discontinued at 0.7m - backhoe refusal

Type

138

137

136

135

134

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments


1

2

3

4






REMARKS:

RIG: 8T Backhoe




WellConstruction

Details

D

D

D

0.15

0.5

0.65

0.25

0.6

0.7

1.0

TOPSOIL - light brown silty topsoil with some ironstonegravel and clay and a trace of grass rootlets

SILTY CLAY - hard red brown mottled light brown siltyclay

SHALY CLAY -hard grey brown mottled orange brownshaly claySHALE - very low to low strength brown shale with somemedium strength bands


Type

142

141

140

139

138

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments


1

2

3

4






REMARKS:

RIG: 8T Backhoe





5 10 15 20


D

D

D

0.1

0.4

0.9

0.2

0.6

0.95

TOPSOIL - light brown silty topsoil with some fine grainedsand a trace of grass rootlets

SANDY CLAY -stiff to very stiff orange brown and greysandy clay

SANDSTONE - low to medium strength grey and greybrown sandstone


Type

145

144

143

142

141

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments


1

2

3

4






REMARKS:

RIG: 8T Backhoe




WellConstruction

Details

D

D

D

0.1

0.5

0.9

0.15

0.7

1.1

1.4

TOPSOIL - light brown silty topsoil with some clay anda trace of grass rootletsSILTY CLAY - very stiff red brown mottled light brown siltyclay

SANDY CLAY - stiff grey/red brown sandy clay (extremelyweathered sandstone)

SANDSTONE - low strength brown and grey brown fine tomedium grained sandstone (possible MIttagongFormation)


Type

148

147

146

145

144

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments


1

2

3

4






REMARKS:

RIG: 8T Backhoe





5 10 15 20


D

D

D

D

0.1

0.5

1.0

1.3

0.1

1.0

1.4

TOPSOIL - brown clayey silty topsoil with a trace of grassrootlessSHALY CLAY - very stiff to hard red brown shaly clay

- from 0.4m: low strength shale bands

SHALE - low to medium strength grey shale


Type

166

165

164

163

162

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments


1

2

3

4






REMARKS:

RIG: 8T Backhoe




WellConstruction

DetailsD

D

D

0.05

0.5

1.3

0.25

1.1

1.4

TOPSOIL - light brown silty topsoil with some fine grainedsand and clay and a trace of grass rootlets

SILTY CLAY - very stiff to hard red brown mottledorange/red brown silty clay

- from 0.8m: becoming grey

SANDSTONE - low to medium strength brown sandstone


Type

159

158

157

156

155

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments


1

2

3

4






REMARKS:

RIG: 8T Backhoe




WellConstruction

Details

D

D

D

0.5

1.0

1.3

0.25

0.5

1.5

1.8

TOPSOIL - light brown sandy silty topsoil with some fineto medium ironstone gravel and a trace of grass rootlets


SANDY CLAY - very stiff grey/red brown/orange brownsandy clay (extremely weathered sandstone)

- from 1.0m: some ironstone and low strength sandstonebands

SANDSTONE - low strength grey and orange brown fineto medium grained sandstone


Type

150

149

148

147

146

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments


1

2

3

4






REMARKS:

RIG: 8T Backhoe




WellConstruction

Details

D

D

D

0.5

1.0

1.6

0.3

1.4

1.9

2.1

TOPSOIL - light brown silty topsoil with some clay andgrass rootlets

SILTY CLAY - very stiff light brown mottled red brown siltyclay with a trace of fine rootlets

- from 0.9m: grey mottled red brown

SANDY CLAY - hard grey and red brown sandy clay(extremely weathered sandstone)

SANDSTONE - low to medium strength brown and greyfine to medium grained sandstone


Type

151

150

149

148

147

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments


1

2

3

4






REMARKS:

RIG: 8T Backhoe




WellConstruction

Details

D

D

D

D

0.5

1.0

1.5

2.0

0.15

0.4

0.8

1.0

TOPSOIL - light brown silty topsoil with some fine grainedsand and grass rootletsSILTY CLAY - stiff orange brown mottled red brown siltyclay with some sand

SANDY CLAY - stiff to very stiff grey/red brown/orangebrown sandy clay with some ironstone bands (extremelyweathered sandstone)

SANDSTONE - low strength grey and orange brownsandstone


Type

158

157

156

155

154

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments


1

2

3

4






REMARKS:

RIG: 8T Backhoe




WellConstruction

Details

D

D

D

0.1

0.5

0.9

1.0

0.15

0.7

1.4

TOPSOIL - brown clayey silty topsoil with a trace ofgrass rootletsSILTY CLAY - very stiff to hard red brown silty clay

- from 0.5m: very low to low strength bands



Type

174

173

172

171

170

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments


1

2

3

4






REMARKS:

RIG: 8T Backhoe





5 10 15 20


D

D

D

0.1

0.5

1.3

0.2

1.4

1.9

2.2

TOPSOIL - light brown clayey silty topsoil with somegrass rootlets

SANDY CLAY - very stiff red brown and orange brownslightly sandy clay

SANDSTONE - very low strength, highly weatheredgrey/red brown sandstone

SANDSTONE - low to medium strength grey brownsandstone


Type

165

164

163

162

161

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments


1

2

3

4






REMARKS:

RIG: 8T Backhoe




WellConstruction

Details

DU50

D

D

D

0.4

0.5

0.78

1.0

1.5

2.0

0.15

1.1

1.6

1.9

TOPSOIL - light brown clayey silty topsoil with a trace ofgrass rootletsSILTY CLAY - hard red brown silty clay

- from 0.6m: red brown mottled light brown silty clay

SANDSTONE - very low strength, highly weatheredsandstone with some ironstone bands

SANDSTONE- low strength grey and grey brown finegrained sandstone with some medium strength sandstoneand ironstone bands


Type

169

168

167

166

165

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments


1

2

3

4






REMARKS:

RIG: 8T Backhoe





5 10 15 20


D

D

D

D

0.1

0.5

1.0

1.5

0.15

0.7

1.2

1.7

1.9

TOPSOIL - brown clayey silty topsoil with some grassrootletsSILTY CLAY - very stiff red brown silty clay with a trace ofgrass rootlets

SHALE - low to medium strength grey and brown highlyfractured shale

SHALE - extremely low strength, grey and orange brownshale



Type

176

175

174

173

172

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments


1

2

3

4






REMARKS:

RIG: 8T Backhoe




WellConstruction

Details

D

D

D

D

D

0.1

0.5

1.0

1.5

1.8

0.15

0.45

1.1

TOPSOIL - light brown silty topsoil with a trace ofironstone gravel, clay and grass rootletsSILTY CLAY - hard grey mottled red brown silty clay

SHALE - very low strength grey and brown shale withsome bands of low to medium strength shale

- from 0.9m: low to medium strength


Type

204

203

202

201

200

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments


1

2

3

4






REMARKS:

RIG: 8T Backhoe





5 10 15 20


D

D

D

0.1

0.4

0.9

0.25

1.2

1.5

1.7

TOPSOIL - brown silty clayey topsoil with some sand andgrass rootlets

SANDY CLAY - very stiff red brown mottled grey brownsilty clay with a trace of rootlets

SANDY CLAY - stiff grey and orange brown sandy clay(extremely weathered sandstone)

SANDSTONE - low to medium strength grey and greybrown sandstone


Type

176

175

174

173

172

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments


1

2

3

4






REMARKS:

RIG: 8T Backhoe




WellConstruction

Details

D

D

D

D

0.5

1.0

1.3

1.6

0.2

0.8

1.2

1.7

TOPSOIL - brown clayey silty topsoil with some grassrootlets

SILTY CLAY - very stiff red brown mottled orange brownsilty clay

SHALY CLAY - very stiff to hard grey and orange brownshaly clay

SHALE - very low strength grey shale with bands of low tomedium strength shale


Type

207

206

205

204

203

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments


1

2

3

4






REMARKS:

RIG: 8T Backhoe




WellConstruction

Details

DU50

U50

D

D

0.35

0.450.5

0.75

0.9

1.0

1.6

0.15

0.9

1.4

1.7

TOPSOIL - brown clayey silty topsoil with some coarsesand and grass rootletsSILTY CLAY - very stiff red brown mottled light brown siltyclay with a trace of rootlets

SHALY CLAY - very stiff grey mottled red brown shaly clay

SHALE - very low strength grey shale with some bands oflow to medium strength brown shale


Type

181

180

179

178

177

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments


1

2

3

4






REMARKS:

RIG: 8T Backhoe




WellConstruction

Details

D

D

D

0.5

1.0

1.6

0.2

0.9

1.5

1.8

TOPOIL - brown clayey silty topsoil with some grassrootlets

SANDY CLAY - very stiff red brown mottled orange brownsilty clay

SANDY CLAY - stiff to very stiff grey/orange brown/redbrown sandy clay (extremely weathered sandstone)

SANDSTONE - low to medium strength brown and orangebrown fine to medium grained sandstone (possibleMittagong Formation)


Type

185

184

183

182

181

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments


1

2

3

4






REMARKS:

RIG: 8T Backhoe





5 10 15 20


D

D

D

D

D

0.1

0.5

1.0

1.4

1.7

0.2

1.0

1.4

1.7

TOPSOIL - brown clayey silty topsoil with some fineironstone gravel and a trace of gravel rootlets


from 0.6m: becoming grey mottled orange brown

SHALY CLAY - very stiff grey mottled orange brown shalyclay with some bands of low to medium strength greyshale



Type

195

194

193

192

191

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments


1

2

3

4






REMARKS:

RIG: 8T Backhoe




WellConstruction

Details

D

D

D

D

0.5

0.8

1.2

1.6

0.1

0.9

1.3

TOPSOIL - brown clayey silty topsoil with some rootletsand a trace of sandSILTY CLAY - very stiff red brown silty clay

from 0.6m: becoming grey brown mottled red brown

SHALE - very low to low strength brown shale


Type

206

205

204

203

202

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments


1

2

3

4






REMARKS:

RIG: 8T Backhoe




WellConstruction

Details

D

D

D

0.3

0.5

1.0

0.15

1.3

1.9

2.1

TOPSOIL - brown clayey silty topsoil with a trace of grassrootlets and loose sandSILTY CLAY - very stiff then hard red brown mottled lightbrown silty clay with a trace of rootlets

- from 0.7m: becoming grey mottled orange brown

CLAY - stiff grey clay with a trace of fine ironstone gravel

- from 1.7m: becoming shaly clay



Type

206

205

204

203

202

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments


1

2

3

4






REMARKS:

RIG: 8T Backhoe





5 10 15 20


D

D

U50

D

D

D

0.1

0.5

0.6

0.951.0

1.5

2.0

0.1

0.7

1.1

1.3

TOPSOIL - brown clayey silty topsoil with some grassrootletsSILTY CLAY - very stiff red brown silty clay with a trace offine ironstone gravel

SANDY CLAY - stiff grey /red brown /orange brown sandyclay (extremely weathered sandstone)

SANDSTONE - low to medium strength fine to mediumgrained red brown and grey sandstone (possibleMittagong Formation)Bore discontinued at 1.3m

Type

193

192

191

190

189

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments


1

2

3

4






REMARKS:

RIG: 8T Backhoe




WellConstruction

Details

D

D

D

0.5

1.0

1.2

0.2

0.8

1.9

2.1

2.4

TOPSOIL - brown silty topsoil with some clay and grassrootlets

SILTY CLAY - hard red brown silty clay with someironstone gravel and a trace of grass rootlets

CLAY - stiff to very stiff grey mottled red brown slightlysilty clay

SANDSTONE - very low strength , extremely weatheredgrey mottled orange brown sandstone

SANDSTONE - low to medium strength grey sandstone(possible Mittagong Formation)


Type

192

191

190

189

188

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments


1

2

3

4






REMARKS:

RIG: 8T Backhoe




WellConstruction

Details

B

D

D

D

0.4

0.7

1.0

1.5

2.0

0.1

0.3

0.9

1.4

2.0

TOPSOIL - brown silty topsoil with some clay and grassrootletsCLAYEY SILT - brown and grey brown clayey silt with atrace of fine ironstone gravel and grass rootletsSILTY CLAY - stiff light brown and red brown silty claywith a trace of fine ironstone gravel

SHALY CLAY - grey shaly clay with some ironstone gravel- from 1.2m: becoming low strength brown shale

SHALE - extremely low to very low strength grey shalewith some low strength bands

- from 1.8m: becoming low strength brown shale


Type

217

216

215

214

213

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments


1

2

3

4






REMARKS:

RIG: 8T Backhoe




WellConstruction

Details

D

D

D

D

0.5

1.0

1.5

1.9

2.0

0.4

0.6

TOPSOIL - silty clayey topsoil with some grass rootletsand ironstone gravel

SHALE - low strength, brown then grey, medium strengthshale


Type

224

223

222

221

220

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments


1

2

3

4






REMARKS:

RIG: 8T Backhoe





5 10 15 20


0.2

1.4

1.7

2.0

TOPSOIL - clayey silty topsoil with some grass rootlets

SILTY C LAY -stiff to very stiff red brown with some lightbrown silty clay-from 0.7m: becoming grey mottled red brown with a traceof ironstone gravel

SHALY CLAY - stiff grey shaly clay with some ironstonegravel

SHALE - extremely low to very low strength with some lowstrength band- from 1.9m: becoming low to medium strength


Type

229

228

227

226

225

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments


1

2

3

4






REMARKS:

RIG: 8T Backhoe




WellConstruction

Details

D

D

D

D

0.5

1.0

1.5

1.9

2.0

0.15

0.8

1.2

1.8

TOPSOIL - clayey silty topsoil with some grass rootletsand a trace of ironstone gravelSILTY CLAY - stiff light brown mottled red brown silty claywith a trace of grass rootlets

SHALY CLAY - stiff grey and orange brown shaly clay withsome ironstone gravel

SHALE - very low to low strength grey and brown shale


Type

215

214

213

212

211

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments


1

2

3

4






REMARKS:

RIG: 8T Backhoe




WellConstruction

Details

D

D

D

0.5

1.0

1.5

0.15

0.6

0.9

1.4

TOPSOIL - brown sandy silty clay topsoil with some grassrootletsSILTY CLAY - stiff red brown silty clay with a trace of fineironstone gravel and grass rootlets

SHALY CLAY - stiff to very stiff grey mottled brown shalyclay with some ironstone gravel

SHALE - very low to low strength brown shale


Type

244

243

242

241

240

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments


1

2

3

4






REMARKS:

RIG: 8T Backhoe




WellConstruction

Details

D

D

D

0.5

0.7

0.8

1.3

1.4

0.3

0.8

1.3

1.7

1.9

FILLING - brown clayey silty filling with some grassrootlets and igneous cobbles

SILTY CLAY - stiff to very stiff grey and red brown siltyclay with a trace of fine ironstone gravel

SHALY CLAY - stiff grey shaly clay with some ironstonegravel

SHALE - extremely low strength grey shale with somebands of ironstone and very low to low strength shale

SHALE - low strength grey shale


Type

226

225

224

223

222

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments


1

2

3

4






REMARKS:

RIG: 8T Backhoe




WellConstruction

Details

D

D

D

0.5

1.0

1.9

0.2

0.8

1.2

1.7

TOPSOIL - brown silty topsoil with some clay and grassrootlets

SILTY CLAY - very stiff red brown silty clay with a trace ofgrass rootlets

SHALY CLAY - very stiff grey orange brown shaly claywith some ironstone gravel- from 0.95m: some bands of very low to low strengthbrown shale

SHALE - low strength brown and grey brown shale


Type

247

246

245

244

243

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments


1

2

3

4






REMARKS:

RIG: 8T Backhoe





5 10 15 20


D

DU50

D

D

0.1

0.4

0.5

0.7

1.0

1.5

0.5

0.9

1.4

TOPSOIL - clayey silty topsoil with a trace of grass rootlets

SILTY CLAY - very stiff red brown silty clay with a trace offine ironstone gravel0.6m: becoming grey mottled red brown

SHALE - grey extremely low to very low strength shale- from 1.2m: becoming low to medium strength


Type

232

231

230

229

228

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments


1

2

3

4






REMARKS:

RIG: 8T Backhoe




WellConstruction

Details

D

B

D

D

0.1

0.4

0.7

1.0

1.3

0.25

0.8

1.2

TOPSOIL - brown/red brown clayey silty topsoil with atrace of grass rootlets

SILTY CLAY - very stiff grey mottled red brown clay with atrace of fine ironstone gravel

SHALE - low to medium strength grey/brown and brownshale


Type

248

247

246

245

244

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments


1

2

3

4






REMARKS:

RIG: 8T Backhoe




WellConstruction

Details

D

D

D

0.1

0.5

1.0

0.35

1.3

2.1

2.5


SILTY CLAY - very stiff red brown and grey silty clay witha trace of fine ironstone gravel

SHALY CLAY - stiff grey and orange brown shaly clay withsome ironstone gravel

SHALE - extremely low strength grey shale with someironstone bands and very low strength bands


Type

262

261

260

259

258

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments


1

2

3

4






REMARKS:

RIG: 8T Backhoe





5 10 15 20


D

U50

D

D

D

0.1

0.5

0.87

1.0

1.5

2.2

0.15

0.9

1.1

1.4

TOPSOIL - brown clayey silt topsoil with some grassrootletsSILTY CLAY - stiff to very stiff brown mottled light brownsilty clay with a trace of grass rootlets- from 0.4m: becoming light brown and red brown

SHALY CLAY - stiff grey shaly clay with some ironstonegravel/ bands

SHALE - very low strength grey shale with some lowstrength bands


Type

244

243

242

241

240

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments


1

2

3

4






REMARKS:

RIG: 8T Backhoe




WellConstruction

Details

D

D

D

0.5

1.0

1.3

1.4

0.4

0.8

1.0

TOPSOIL - brown clayey silty topsoil with some fineironstone gravel and grass rootlets

SILTY CLAY - very stiff red brown and light brown siltyclay



Type

255

254

253

252

251

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments


1

2

3

4






REMARKS:

RIG: 8T Backhoe




WellConstruction

Details

D

D

0.2

0.5

0.3

0.9


SHALE - low strength brown then grey shale- from 0.6m: becoming low to medium strength


Type

256

255

254

253

252

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments


1

2

3

4






REMARKS:

RIG: 8T Backhoe




WellConstruction

Details

D

D

0.2

0.6

0.15

0.9

1.1

1.3

TOPSOIL - silty topsoil with some clay and grass rootlets

SILTY CLAY - stiff to very stiff brown mottled grey andorange brown silty clay-from 0.5m: becoming red brown

CLAY - stiff to very stiff grey clay with some silt and a traceof fine rootlets

SHALE - grey and dark grey very low to low strength shale


Type

267

266

265

264

263

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments


1

2

3

4






REMARKS:

RIG: 8T Backhoe




WellConstruction

Details

D

D

D

0.5

1.0

1.1

1.2

0.25

0.9

2.0

2.2

2.4

TOPSOIL - brown silty topsoil with some clay and grassrootlets, tree rootlets and a trace of large sandstone gravel

SILTY CLAY - very stiff then hard grey mottled red brownclay with a trace of fine rootlets- from 0.7m: becoming grey mottled orange brown

SANDY CLAY - very stiff to hard grey mottled orangebrown slightly sandy clay with a trace of white gravelinclusions

SANDSTONE - extremely low strength grey fine grainedsandstone

SANDSTONE - very low to low strength grey fine grainedsandstone with some ironstone bands (possible MittagongFormation)Bore discontinued at 2.4m

Type

267

266

265

264

263

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments


1

2

3

4






REMARKS:

RIG: 8T Backhoe





5 10 15 20


D

D

D

D

D

0.15

0.5

1.0

1.5

2.3

0.3

1.3

2.3

2.7

TOPSOIL - brown silty topsoil with some clay, grassrootlets and medium to coarse ironstone gravel

SILTY CLAY - stiff to very stiff red brown silty clay with atrace of fine ironstone gravel and rootlets-from 0.7m: becoming light brown mottled red brown

SANDY CLAY - stiff grey slightly sandy clay with someironstone gravel

SHALE/FINE SANDSTONE` - extremely low strength greyfine grained sandstone with some very low strengthsandstone and high strength ironstone bands (possibleMittagong Formation)


Type

281

280

279

278

277

Depth(m)

1

2

3

4

RL

Wat

er

Dep

th

Sam

ple

Descriptionof

Strata Gra

phic

Log

Results &Comments


1

2

3

4






REMARKS:

RIG: 8T Backhoe




WellConstruction

Details

B&D0.7-0.8

D

D

D

D

0.5

1.0

1.5

2.0

2.6

Appendix E

Laboratory Test Results – Geotechnical

Appendix F

Laboratory Test Results – Salinity

Douglas Partners Pty Ltd ABN 75 053 980 117

www.douglaspartners.com.au 96 Hermitage Road

West Ryde NSW 2114 PO Box 472

West Ryde NSW 1685 Phone (02) 9809 0666

Fax (02) 9809 4095

Brisbane • Cairns • Canberra • Darwin • Gladstone • Gold Coast • Macarthur • Melbourne • Newcastle • Perth • Sunshine Coast •Sydney • Townsville • Wollongong • Wyong

TEXTURAL CLASSIFICATION TEST RESULTS

Project: Wilton Junction Project No.: 73467 Location: Hume Highway & Picton Road, Wilton Date: 27/05/13

Sample No. Depth (m) Soil Texture Group Multiplication Factor

TP1 0.1 Light Clay 8.5


TP1 0.5 Light Medium Clay 8.0

TP1 1.0 Medium Clay 7.0





TP4 0.1 Clay Loams 9.0



















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Report on Geotechnical Assessment – Wilton Junction Project 73467.00Hume highway and Picton Road, Wilton July 2013






TP15 0.1 Loams 10.0















TP21 1.0 Heavy Clays 6.0













of 4








TP28 1.0 Heavy Clays 6.0





TP31 0.3 Loams 10.0






















of 4





TP42 0.2 Loams 10.0









Tested by: SI Checked by: RCB

Please refer to the last page of this report for any comments relating to the results.

Appendix G

CSIRO Guide to Home Owners on Foundation Maintenance and Footing Performance

AGS, Australian Geoguides LR1 to LR9

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