gillman structure plan - south australia...p5907-final report gillman structure plan.30 april 09 5.5...

GILLMAN STRUCTURE PLAN Towards the Release of Industrial Land

FINAL REPORT

Prepared for the

LAND MANAGEMENT CORPORATION

by

In association with Tonkin Consulting Eco Management Services Ann Shaw Rungie

April 2009

P5907-Final Report Gillman Structure Plan.30 April 09

TABLE OF CONTENTS

1 INTRODUCTION 1

1.1 Background 1

1.2 Study Area 1

1.3 The Brief 3

1.4 Purpose of This Report 4

1.5 Consultation Undertaken 4

2 STUDY CONTEXT 5

2.1 Strategic Significance of the Region 5

2.2 SA Industrial Land Strategy 7

2.3 Regional Stormwater Management 8

3 GENERAL CONSTRAINTS 9

3.1 Geotechnical 9 3.1.1 Regional Geology 9 3.1.2 Natural Soils 9

3.2 Stormwater 10

3.3 Chemically Aggressive Soils 11

3.4 Gas Mains 12

3.5 Brine Pipeline 13

3.6 Sea- level Rise / Storm Impacts 13

3.7 Other Physical Infrastructure 14 3.7.1 General 14 3.7.2 Electricity 14

4 HOW MUCH LAND CAN BE DEVELOPED? 15

4.1 Land Available in the Short Term 15 4.1.1 Stormwater Management 15 4.1.2 Protection of Coastal Waters and Ecosystems 15

4.2 Land Potentially Available in Medium to Longer Term 18

5 ISSUES TO BE ADDRESSED TO ENABLE DEVELOPMENT TO OCCUR 19

5.1 Site Stormwater Management 19

5.2 Chemically Aggressive Soils 21

5.3 Protection from Sea Inundation 21 5.3.1 Protection Options 21 5.3.2 Condition of Existing Levee 22 5.3.3 Height of New Levee 23

5.4 Filling of Land / Land Subsidence / Earthquake Risk 23 5.4.1 Overview 23 5.4.2 Land Subsidence 25 5.4.3 Height of Fill 25 5.4.4 Edge of Fill 25

P5907-Final Report Gillman Structure Plan.30 April 09

5.5 Provision of Physical Infrastructure 26 5.5.1 Headworks Requirements 26 5.5.2 Impact of Chemically Aggressive Soils 26

5.6 Movement Systems 27 5.6.1 Road 27 5.6.2 Rail 28 5.6.3 Pedestrian Movement 29 5.6.4 Cyclists 29 5.6.5 Public Transport 30

5.7 Public Access to Coastal Environments 30

5.8 Creation of Sustainable Ecosystems 30 5.8.1 Introduction of Tidal Flushing 30 5.8.2 Appropriate Planting Selection 31 5.8.3 Flora and Fauna 31

5.9 Protection of Coastal Water Quality 32

5.10 Footing Design 34

5.11 On-going Management / Monitoring 35

5.12 Land Use Zoning 35 5.12.1 Existing Development Plan 35 5.12.2 Draft Industry Development Plan Amendment by Council 36

6 FINAL STRUCTURE PLAN 38

6.1 Initial Structure Plans 38

6.2 Key Amendments Arising from Stakeholder Feedback /

Additional Investigations 38

6.3 Overview 38

6.4 Extent of Developable Land - Short Term 38

6.5 Extent of Developable Land - Longer Term 39

6.6 Additional Investigations to Identify Further Developable Land 41

6.7 Final Structure Plan 41

6.8 Staging 41

REFERENCES APPENDICES: Appendix 1: Stakeholder Submissions to the Draft Report Appendix 2: Land Fill Methods and Materials Appendix 3: Management of Acid Sulphate Soil Material Appendix 4: Draft Structure Plan Options FIGURES: Figure 1 Study Area Figure 2 Planning Strategy Figure 3 Southern Ponding Basin Figure 4 Area Currently Subject to Inundation Figure 5 Land Potentially Available Figure 6 Indicative Cross Section for New Levee Figure 7 Location of Bead Samphire Figure 8 Short Term Development Areas Figure 9 Final Structure Plan Figure 10 Indicative Staging of Development

Detailed Structure Plan, Gillman Final Report

J e n s e n Page 1 P L A N N I N G & D E S I G N

1 INTRODUCTION

1.1 Background

The Land Management Corporation has engaged a consultant team led by Jensen Planning and Design (including Tonkin Consulting, Eco-Management Services and Ann Shaw Rungie) to prepare a Structure Plan for land generally known as Gillman within the suburbs of Gillman and Dry Creek in Adelaide. The Government of South Australia controls approximately 500 hectares of contiguous undeveloped land which is identified in the Metropolitan Adelaide Industrial Land Strategy as a key site for future industrial development activity to provide a supply of industrial land over a period of some 20 years. The Adelaide City Council also has an ownership interest in some of this land and owns the adjoining parcel (the Wingfield Eco-Resource Management Centre). The LMC, as the State's Land Development Agency, will play a lead government role in development activities for the area and directly controls much of the subject land on behalf of the State Government. The City of Port Adelaide Enfield is the local government authority responsible for the area in which the subject land is located. Council has a specific interest in how the land is developed (particularly in relation to infrastructure that will become the property of Council and / or the responsibility of the Council to maintain) and the responsibility for the ongoing regulation and control of development within the Gillman area. The subject land has been identified for future industrial use since the 1940's. In the late 1980's and early 1990's the land was earmarked for the establishment of a high-technology mixed-use precinct termed the Multi-Function Polis or "MFP". However, following much research and detailed feasibility studies, the State Government decided not to proceed with the MFP Project (other than the construction of two stormwater wetlands). Recent studies have refocused on the future use of the land for industrial purposes.

1.2 Study Area

The Study Area comprises approximately 550 hectares of land located within the suburbs of Gillman and Dry Creek. The land is generally bound to the north by North Arm, to the east by the Wingfield Eco-Resource Management Centre, to the south by the Port Adelaide Expressway and Eastern Parade, and to the west by Whicker Road and Grand Trunkway (refer Figure 1). The land is vacant other than for some privately owned sites adjacent to Eastern Parade, the Range Wetland and the Magazine Creek Wetland.



FIGURE 1: Study Area



1.3 The Brief

The LMC Brief is for the Project to facilitate future integrated development of the subject land for appropriate industrial use and to provide a suitable framework for this future development to occur. The development of, or the removal of constraints to development for the subject land is the key driver for the Consultancy and represents a tangible step toward achieving the over - arching goal of releasing industrial land to the market. The LMC is seeking a "Detailed Structure Plan" which will identify areas of the subject land where constraints to development are relatively well understood to facilitate either development in these areas, or the commencement of works to remove / overcome these constraints to facilitate development in the near term. The Consultant is to make preliminary assessments as to whether works could reasonably be undertaken to remove the constraints to facilitate industrial development activities or whether land should be retained as open space for the short, medium or long-term. Where areas of open space are to be retained in the longer term, the aim of the Consultancy is to ensure that those areas provide functionality for a range of possible uses (e.g. biodiversity retention, stormwater management, passive recreation, etc.). The Plan should identify "super lots" and should focus on the location and staging of headworks infrastructure (including the identification of corridors / locations for major headworks infrastructure) that will facilitate development of the "super lots". Detailed subdivision plans will be developed at a future stage (outside of this Consultancy) following consultation with potential end users. Consideration also needs to be given to the principles of sustainable development, including consideration of the proximity and the sensitivity of the adjacent marine environment, the location and extent of habitat of high ecological value that could be retained, the potential for centralised / de-centralised management of potential waste / resource streams, the provision of appropriate community facilities and the basic orientation / location of development parcels. The Consultancy is to incorporate a review and critical assessment of issues identified through previous assessment works for the area and consultation with key stakeholders. Finally, the Consultancy should recommend the scope of additional detailed investigations that may be required in order to determine whether specific parts of the study area can be developed in the future. It is not the role of this Consultancy to resolve all outstanding matters (many of which will be ultimately resolved during the detailed design stage for future development phases), however it is required to critically assess the level of information that would be required to commence such detailed design works in the future.



1.4 Purpose of This Report

This Final Report builds on the earlier draft Report and outlines the analysis of opportunities and constraints to future development of the study area, identifies land that can be developed for industrial purposes in the short term provided specific issues are addressed and without the need for additional significant research, and identifies the longer term Structure Plan to guide future development. Staging and on-going management issues are also addressed. The Report also identifies issues that require further resolution. A Draft Report was completed for the Gillman Structure Plan in February 2008, and following stakeholder consultation it was recognised that a range or transport issues needed to be investigated prior to identifying the extent of land that could be developed as well as identifying the preferred Structure Plan for the Study Area. A separate Transport Study was commissioned by the Department of Planning and Local Government (formerly Planning SA) with input from the Department of Transport, Energy and Infrastructure, the LMC and the City of Port Adelaide Enfield. The work was undertaken QED Pty Ltd and these investigations have influenced the recommendations in this Final Report for the Gillman Structure Plan.

1.5 Consultation Undertaken

As part of the preparation of the Draft Report consultation took place with key stakeholders, largely in the form of a key Stakeholder Workshop held on 21 November 2007. Representatives of the following agencies were represented: City of Port Adelaide Enfield Defence SA Flinders Ports Planning SA City of Adelaide SA Water DTEI

EPA Coastal Management Branch Department of Premier and

Cabinet (Sustainability Programmes)

AML NRM Board DTED

Following the release of the draft Report to the stakeholders in February 2007 feedback was sought and obtained in the form of a second Stakeholder Workshop and subsequently written submissions (refer to Appendix 1). This feedback was considered by the consultants and the LMC and incorporated into this Final Report as considered appropriate.



2 STUDY CONTEXT

2.1 Strategic Significance of the Region

The Gillman/LeFevre Peninsula area is consistently mentioned in State economic development strategies as being a key area for future industrial growth and investment. The South Australian Government recognises that if the State is to meet the growth targets set in the Strategic Plan, facilitating industrial development in this region will be of critical importance. The level of public investment directed to infrastructure projects in the region demonstrates its significance. Recently, both State and Federal Government have embarked on major infrastructure upgrades that directly benefit the Port Adelaide/LeFevre Peninsula region and make it more attractive as a major import/export and distribution hub. Some of these projects include the LeFevre Peninsula freight and rail corridor link to Outer Harbour, deepening of the Outer Harbour shipping channel to accommodate Panamax and post-Panamax vessels, and the Port River Expressway (stage 1), which has now been completed. This four-lane expressway linking Port Wakefield Road (and NExy) to Outer Harbour provides a convenient and high quality freight connection between the State’s northern regions and the Port. The LeFevre Peninsula features strongly in the State Government’s plans to treble the State’s exports to $25 billion by 2013 (SA Export Council 2004), and the Metropolitan Planning Strategy (Planning SA 2007) actively encourages the development of freight and intermodal facilities in the area. The private sector has also recognised the enormous growth potential of the area, as demonstrated by the Port Waterfront project – a large scale residential development including some 2000 apartments and tourism-related development around the Port Adelaide area (in joint venture with the Land Management Corporation). DTEI’s Strategic Infrastructure Plan (2005) specifically mentions the Gillman site as one of a handful of “key precincts requiring prioritised investment”. Other key precincts for future industrial growth are also centered around the LeFevre Peninsula, one such precinct being the Techport shipbuilding site at Osborne. The strategic location of the LeFevre Peninsula area close to employment markets and transport infrastructure makes it invaluable from an industrial development point of view. The significance of the region is also illustrated in the Planning Strategy for South Australia (Planning SA 2007), which envisages the Gillman/Dry Creek area as a future “industrial hub with a focus on waste management and recycling” (refer to Figure 2). The strong emphasis placed on developing infrastructure to improve trade and export capabilities, coupled with the host of policies contained in the Strategic Plan that are directly concerned with encouraging business and industry clusters around key intermodal facilities mean that the Gillman/LeFevre Peninsula area will continue to be a priority area for industrial investment and growth.



FIGURE 2: Planning Strategy



2.2 SA Industrial Land Strategy

Gillman is identified as a ‘Strategic Industrial Area’ in the State Government’s Industrial Land Strategy (April 2007). The Strategy, which provides a framework for the development of industrial land in Metropolitan Adelaide in the short (1-5 years), medium (5-10 years) and long term (10-15 years), recognises the economic importance of the site to the State, based on a number of characteristics: its size (being large enough for industries that have substantial land

requirements); its favourable location in relation to major freight routes and other road

and rail networks (both existing and proposed); the potential of the site to perform a significant export function (being

near the port); its proximity to key existing industrial areas; its separation from sensitive land uses (providing greater opportunity for

general industrial development and 24-hour operations) its proximity to employment markets. These combined characteristics are seen as being highly desirable for industrial land, warranting long term protection from incompatible or competing uses. In recent years, the State Government has made considerable investments in transport infrastructure in the northern and north-western sectors (for example, the Port River Expressway and the Northern Expressway, currently under construction), and the Strategy predicts that areas such as Gillman – which are strategically located in terms of access to this infrastructure – are likely to experience continued growth, fuelled by demand from industries dependent on freight corridors. The Strategy also makes reference to industry preferences for central sites (as opposed to sites in the outer north, such as Elizabeth or Burton). The need to preserve and realise the development potential of strategic areas like Gillman is emphasised in the first Action in the Strategy: “Encourage Councils to adopt policies and zoning provisions within Development Plans to protect strategic and other industrial sites to secure future industrial activities”.

Part of the Gillman site has been ear-marked in the Strategy as an Eco-Industrial Precinct for resource recovery activities and other industrial uses. This precinct, which comprises approximately 50 hectares, has been identified as Constrained Industrial Land, due to low site levels, stormwater and sea flooding, marine rehabilitation, acid sulphate soils, inappropriate zoning, infrastructure and service provision.



2.3 Regional Stormwater Management

Large portions of the Study Area are currently utilised for the purposes of detaining stormwater runoff. Catchments draining northern metropolitan Adelaide discharge to the Magazine Creek and Range wetlands, which spill into the ‘Northern’ and ‘Southern’ Ponding Basins respectively.

These areas provide a stormwater drainage and flood mitigation function as follows:

During times of high tide, stormwater accumulates and ponds in the

wetlands and ponding basins; When tide levels are sufficient low, stormwater drains to Barker Inlet by

gravity via a tide gate structure that regulates these flows The peak flood levels in the ponding basins are designed to be

sufficiently low so as to not cause ‘backing up’ of floodwaters. Low lying developed areas in Wingfield, Ottoway, Gillman and Port Adelaide are reliant on the adequate performance (ie. low flood level) of the wetlands and ponding basins in order to not suffer property inundation and flood damage.

The existing Southern Ponding Basin is shown in Figure 3 below.

FIGURE 3: Southern Ponding Basin (Wingfield Landfill in Background)



3 GENERAL CONSTRAINTS

3.1 Geotechnical 3.1.1 Regional Geology

The site lies within the physiographic zone referred to as the Estuarine Plain. Prior to the levee being constructed, the site largely comprised intertidal mangrove woodland and mud flats. The geological units consist of, with increasing depth: St Kilda Formation Pooraka Formation Glanville Formation Hindmarsh Clay

3.1.2 Natural Soils The soils of the St Kilda Formation generally, and the layers of peat and organic soils in particular, are known to be weak and highly compressible. Groundwater is expected to be encountered at mean sea level and may be subjected to tidal and seasonal variations. The extent of tidal variations would be expected to decrease with increasing distance from the Port Adelaide River or North Arm. The weak and compressible soils within the St Kilda Formation have the following associated problems: Large settlements are likely to occur during filling of the site, with higher

settlements likely to occur closer to North Arm Trafficability on these soils is expected to be poor Shallow groundwater would require shoring of excavations and

dewatering, if deep excavations were to be pursued. It is recommended elsewhere in this report that the existing soils not be disturbed to reduce the possibility of Acid Sulphate Soil conditions occurring

The soils of the St Kilda Formation will be generally unsuitable to support footings

Footings founded on engineered fill above the St Kilda Formation must be designed based on relatively low bearing pressures

These soils have low CBR values, resulting in relatively large pavement thicknesses

Ground improvement works would be required to reduce the service settlements

As such, ground improvement methods will need to be incorporated into the detailed design of the development. This is discussed further in Section 5.4.



3.2 Stormwater

The flooding behaviour of the wetlands and ponding basins has previously been assessed through modelling undertaken for the Port Adelaide Seawater Stormwater Study (Tonkin Consulting and WBM, 2005). While a range of conditions were assessed, the results presented below correspond to model inputs / parameters / assumptions summarised as follows: Sea Level Rise: 500 mm Tide Condition: MHWS tide hydrograph (ie. peak tide level of 1.50 mAHD) Rainfall / Stormwater Condition: long duration (24-36 hour) 100 year ARI

storm Ponding Basins assumed to be ‘empty’ at start of event. No pumping of stormwater from basins to the sea. No direct discharge of stormwater to the marine environment. No allowance made for evaporation from the ponding basins. The model determined peak 100 year ARI flood levels as summarised in the Table 1 below. A ‘future conditions’ scenario was also assessed, which assumed ultimate development throughout the upstream catchment, and an increase in rainfall intensity of 10% associated with climate change. Location Flood Level - Existing

Conditions (mAHD) Flood Level – Future Conditions (mAHD)

Maximum desirable flood level1 (mAHD)

Magazine Creek Wetland 0.60 0.68 0.70 Northern Ponding Basin 0.60 0.67 0.70 The Range Wetland 1.12 1.16 1.50 Southern Ponding Basin 0.89 0.92 1.50 1 Preliminary Only Table 1: 100 year ARI Flood Levels – Existing and Future Catchment Development / Rainfall Intensity Conditions The following important points should be considered in reviewing Table 1: The Southern Ponding Basin currently spills into the Northern Ponding

Basin, and is currently unable to flood to a higher level (that is closer to the ‘preliminary’ maximum desirable flood level.

While ‘preliminary’ maximum desirable flood levels have been set, further comprehensive analysis of the upstream drainage systems is required to test the validity of these levels.

No assessment has been made of the likelihood and impacts of an increased groundwater level within the ponding basins associated with sea level rise.

Any development within the wetlands and ponding basins area will need to carefully consider the impact this may have on the 100 year ARI flood level (under future conditions as per the above Table). This is required to ensure that any development will not result in a measurable increase in flood risk to existing low-lying development outside of the Study Area.



3.3 Chemically Aggressive Soils The subject area largely comprised intertidal mangrove woodland and mud flats prior to the levee being constructed. These highly organic soils are Potential Acid Sulphate Soils which are susceptible to becoming Actual Acid Sulphate Soils. Acid Sulphate Soils Acid sulphate soil materials is the term applied to soils, sediment or rock in the environment that contain elevated concentrations of metal sulphides (principally pyrite FeS2 or monosulphides in the form of iron sulphide FeS), which generate acidic conditions when exposed to oxygen. Identified impacts from this acidity cause minerals in soils to dissolve and liberate soluble and colloidal aluminium and iron, which may potentially impact on human health and the environment, and may also result in damage to infrastructure constructed on acid sulphate soil materials. Drainage of peaty acid sulphate soil material also results in the substantial production of the greenhouse gases carbon dioxide (CO2) and nitrous oxide (N2O). The oxidation of metal sulphides is a function of natural weathering processes. This process is slow however, and, generally, weathering alone does not pose an environmental concern. The rate of acid generation is increased greatly through human activities which expose large amounts of soil to air (e.g. via excavation processes). This is most commonly associated with (but not necessarily confined to) mining activities. Soil horizons that contain sulphides are called ‘sulphidic materials’ (Isbell 1996; Soil Survey Staff 2003) and can be environmentally damaging if exposed to air by disturbance. Exposure results in the oxidation of pyrite. This process transforms sulphidic material to sulphuric material when, on oxidation, the material develops a pH 4 or less (Isbell 1996; Soil Survey Staff 2003). Acid sulphate soil materials include potential acid sulphate soil material (sulphidic material) and/or actual acid sulphate soil material (sulphuric material), both of which can occur in the same soil profile. Potential acid sulphate soil material (PASSM or sulphidic material) Potential acid sulphate soil material is material that has not been exposed to air or undergone oxidation and consequently is comprised mostly of accumulations of iron sulphide minerals, one of the end products of the sulphate reduction process. Sulphur occurs in the environment in several oxidation states, as elemental sulphur (S), in an oxidised state (S+6) and in a reduced state (S-2). Several organic and mineral forms of reduced sulphur occur in wetland sediments, but two forms of iron sulphide minerals are of special interest from an environmental point of view: pyrite (FeS2) and iron sulphide (FeS).



Soil and sediment materials rich in iron mono- sulphide (mono-sulphidic black ooze) tend to be very dark and soft. Iron mono-sulphides can react rapidly when they are disturbed (i.e. exposed to oxygen). Pyrite will tend to occur as more discrete crystals in soil and organic matter matrices and will react more slowly when disturbed. The oxidation of iron sulphide in potential acid sulphate soil material (sulphidic material) results in the formation of actual acid sulphate soil material or sulphuric material. Actual acid sulphate soil material (AASSM or sulphuric material) These soils or sediments contain highly acidic soil layers (sulphuric material) caused by aeration of sulphidic material rich in iron sulphides. Sulphuric material is composed either of mineral or organic soil material (15cm or thicker) that has a pH <3.5 and can usually be identified by the presence of bright yellow jarosite mottles or streaks. Mono-Sulphidic Black Ooze (MBO) is located in the low lying, semi-permanently waterlogged areas. Acid Sulphate Soils (ASS) are located south of the levee and Potential ASS (PASS) are found in the mangrove area north of the levee. Under the current hydraulic and drainage regime, there is a low risk for discharge of ASS leachate into the North Arm. The opportunity to remediate the ASS by placing imported suitable quality fill over the ASS has been shown to be an effective amelioration technique. Suitable preventative measures and monitoring will be required during construction.

3.4 Gas Mains

Adelaide - Moomba Gas Pipeline The Epic Energy Adelaide - Moomba Pipeline runs through the Gillman area and supplies gas to the Torrens Island Power Station. The pipeline is a loop line, designed to enable continuing gas supply to the Torrens Island Power Station should failure occur on one side of the power station. The pipeline is buried approximately 900mm below ground level, has a diameter of approximately 550mm, and runs predominately along the levee wall that currently protects Gillman from the sea. It is located within an 18m wide easement. Any works on or adjacent to the existing levee in proximity to the gas main need to ensure protection of the main and provide for future access to it for maintenance purposes.



SEA Gas Main The Port Campbell to Adelaide SEA Gas pipeline is located predominantly to the south of the site, parallel to the Port River Expressway. It is also located within the North Arm Road Reserve and in a parallel easement to the east of Grand Trunkway before crossing over Grand Trunkway and into Moorhouse Road. The average minimum cover is about 1200mm to 1400mm, but there are short sections at the southern extent of the North Arm Road reserve that have less cover than this. At its deepest, near South Road, it has a cover of 3500mm. The majority of the pipeline is marked with marker tape. Construction of the pipeline was completed in January 2004. Any works in close proximity to the gas main needs to ensure protection of the main and should to provide for future access to it for maintenance purposes.

3.5 Brine Pipeline The Penrice Soda Products high pressure brine pipeline traverses the land from south east to north west and represents a potential impediment to the orderly and efficient development of the land. The existing pipe has a diameter of 300mm and it carries crude brine between the Penrice Saltfields and the Osborn Plant at pressures of approximately 100psi. The existing pipeline is constructed of fibrolite and cast iron and is buried beneath the ground at varying depths, estimated to be around 1 metre. The existing pipe is relatively fragile due to its construction materials and age. Tenure arrangements in respect of the Brine line are very unclear because of the proliferation of agreements, changing land ownership over the years and the unregistered nature of the agreements. However the pipeline is protected through a non-registered license between Penrice and the Crown. If filling of land (including compression) occurs over the top of the main, potential exists for damage to the main. Where filling is to occur it may be preferable to relay the main within the new fill material on an alignment more conducive to ongoing maintenance.

3.6 Sea- level Rise / Storm Impacts

Previous studies have established that the existing 100 year ARI tide level is 2.5 mAHD. Existing site levels are well below this level and the Study Area is currently protected by an earth levee, which ranges in elevation (some sections lower than 2.5 mAHD) and construction standard. Current Coast Protection Board (CPB) policy is for coastal development to be designed to be protected against the 100 year ARI tide level, with an additional allowance for wave setup and runup effects, long-term subsidence



and sea level rise (300mm), with allowance made for future works to be constructed to enable protection against a further 700mm of sea level rise. We understand that sea level rise requirements are currently the subject of CPB review. Allowances that would satisfy this policy include: 400mm for wave effects; 500mm over a 50 year period for subsidence; and 250 mm for finished floor level above the finished site level. The current CPB policy allows for land adequately protected by a levee to be developed at a lower level than the levee, subject to adequate protection from stormwater.

3.7 Other Physical Infrastructure

3.7.1 General In order for parts of the land to be developed for industrial purposes, a range of physical infrastructure will need to be provided, including potable water, sewer, power, telecommunications and gas. The key issues with such provision relate to the preferred method of staging of Headwork's infrastructure and ensuring that underground services are not subject to deterioration / failure as a result of the necessary filling of the land and creating suitable building platforms. Further discussion of the issues relating to each of the services is provided in Section 5.6.

3.7.2 Electricity

There are currently two ETSA easements over the site. The main easement contains a 66kV line with the minor easement servicing Moorehouse Road containing an 11kV power line.



4 HOW MUCH LAND CAN BE DEVELOPED?

4.1 Land Available in the Short Term 4.1.1 Stormwater Management

Stormwater flood modelling and mapping has delineated the areas currently subject to inundation from the 100 year ARI event (refer Figure 4). Land that is shown to be outside of the areas inundated by the 'future conditions' 100 year ARI event is considered immediately 'developable' from a stormwater management perspective. The "Lot 3" Grand Trunkway land is shown to be currently subject to inundation by the 100 ARI event, due to the levee separating this land from the ponding basin being relatively low in some locations. Due to a combination of the following factors, development of this land in the short term is also considered appropriate: the volume of water inundating the land is very small in the context of

water held in both ponding basins; the land has historically not been considered as part of the ponding

basins; and a number of opportunities are available to improve the efficiency of the

basins through modifications to levees and tidal gate structures; 4.1.2 Protection of Coastal Waters and Ecosystems

Water Quality

The Magazine Creek and Range Wetlands were both constructed as part of the previous MFP development proposed for the Gillman site. That development was to have residential lakes and the wetlands were intended to intercept and treat urban stormwater from their catchments, in order to protect water quality in the lakes. As the lakes would have been connected to the Port River-North Arm, the river would also have been protected from catchment pollutant sources. In summary, the overall design objectives were: To intercept and treat urban stormwater runoff from its urban/industrial

catchment. The wetlands were designed to easily isolate any spillages of hazardous materials that may have occurred.

To improve visual amenity and provide recreational opportunities. To provide habitat for fauna and flora. To provide opportunities for the harvesting and reuse of stormwater.

It is important to note that all subsequent modelling and proposals for stormwater management in the Study Area have provided for no direct discharge of stormwater to the marine environment and no allowance for pumping of stormwater from basins to the marine environment.



FIGURE 4: Area Currently Subject to Inundation



Because of the urban nature of the former MFP proposal freshwater wetlands were preferred because of the greater landscaping potential and water harvesting and reuse. A study by Tonkin and EMS (1998) indicated that an annual average 345 ML from the Magazine Creek Wetland and 115 ML from the Range Wetland could be harvested. The Magazine Creek is now reasonably well established, although further terrestrial planting is required to achieve its full landscape potential. With the current concept plan for the site, there is no need or intention to modify the wetland, except perhaps for stormwater from the new development being diverted to it. The Range Wetland is less well developed. It consists of 10 individual ponds. The last few ponds have not established very well due to salinisation, with salinity levels exceeding the tolerance of the planted vegetation. While the whole wetland may achieve its intended water quality performance, the condition of the last few ponds in the system detracts from its intended performance. The proximity of the landfill, and the open nature of these ponds with little vegetation would make them an attractive resting area for seagulls, where there would be an accumulation of bird faecal material, introducing nutrients and faecal microorganisms. As it now stands there is a difficulty with the current location of the easternmost section of the existing wetland and the main access road into the area. There may be an opportunity to resolve the access issue and correct the problems with the wetland, resulting in a win-win situation. This would involve relocating either the whole of or just the poorly developed ponds further downstream as part of the rejuvenated intertidal areas (refer Section 5.8.1). The implications for water quality are as follows: The Range wetland is one of the three Gillman wetlands (includes Barker

Inlet Wetland) and intercepts approximately 6% of the catchment of the three wetlands. They all had the same basic design parameters, with regard to residence time, depth, configuration and similar catchment land uses. Consequently it is reasonable to determine their relative water quality function on a pro rata basis.

The loss of approximately half of the wetland area, for example, may result in a loss of approximately 3% of the overall pollutant reduction on a pro rata basis, but is probably much less than this as the inlet ponds in a system have a proportionally higher reduction. However, there is no need to lose this small fraction as additional wetland area can be provided elsewhere.

A new compensatory wetland area, linked to the rejuvenated intertidal area, being closer to the levee would need to be a saline wetland, but could still achieve the basic objectives of water quality, spill interception, habitat and amenity.

This new wetland can be sized dependant on whether the existing Range wetland is retained. The retention or replacement of the Range wetland is also independent of the early stages of development.



Mangroves

No mangroves will be adversely impacted by the proposed development as the proposals do not affect the relationship between the levee and the tidal flats. There are no mangroves surviving on site as a result of the levee (refer Section 5.8.1 on the introduction of tidal flows). There will be no physical impact on the adjacent healthy mangrove communities in North Arm and Barker Inlet system. The maintenance of the existing wetland water quality improvement and protection function and the intention to incorporate WSUD features, including water quality improvement of stormwater from the development, will protect the mangroves. The re-introduction of tidal flows, as discussed in Section 5.8.1 below, will in fact increase the area of mangroves and help preserve the more at-risk saltmarsh habitat within the Study Area.

4.2 Land Potentially Available in Medium to Longer Term Filling within the 100 year ARI event stormwater ponding basins, if not carefully managed, could result in a loss of available flood storage, thereby increasing flood levels and increasing flood risk to land outside of the Study Area. Modelling has been undertaken as part of earlier studies and further modelling is recommended to determine the full extent of land available for development, as outlined in more detail in Section 5.1.



5 ISSUES TO BE ADDRESSED TO ENABLE DEVELOPMENT TO OCCUR

5.1 Site Stormwater Management

A development scenario has previously been considered and assessed to determine the consequential changes to ponding basin flood levels (refer Figure 5). Development within these areas is predicated on the following: Modifying the extent and location of development (filled) areas within the

ponding basins. By selecting relatively higher ground within the ponding basins for development, relatively less flood storage is lost (and development costs are also reduced with less fill volume required to establish the development platform).

Providing a new tidal outlet that serves the Southern Ponding Basin. This element provides a number of advantages, which include increasing the efficiency of discharge from the Southern Ponding Basin, reducing the discharge from this system to the Northern Ponding Basin, and providing the opportunity to establish an inter-tidal wetland system in the Northern Ponding Basin.

Removing the levee bank separating the Northern and Southern Ponding Basins, and utilising the development to separate the systems. This element allows the Northern Ponding Basin to gain more efficient use of flood storage available along the western edge of the existing Southern Ponding Basin, and also assists in the feasibility of establishing the inter-tidal wetland system.

A new Range Wetland Outfall Channel that conveys overflows from this wetland system to the Northern Ponding Basin. This element is required because the existing channel would have to be abandoned due to the proposed creation of Lot 201 over the existing channel alignment.

No allowance for pumping of stormwater, which, if undertaken, may release additional land for development. (it is noted that pumping of stormwater is not Council's preferred option, although it will be considered if there are no other options available).

While further investigations, as described above, are still necessary to assess the sensitivity of upstream drainage systems, Figure 5 provides an indication of the level of development that might be possible in the long term. The extent of development shown is subject to change following these further investigations. In addition, the following principles should be adopted throughout the development:

Employ best practice stormwater management methods including the

applications of Water Sensitive Urban Design (WSUD) principles.



FIGURE 5: Land Potentially Available for Long Term Development



Encourage the harvesting of stormwater for reuse either at the individual allotment scale (harvesting of roof runoff and reuse onsite), communal scale (capture and primary treatment for irrigation reuse), catchment scale (ASR scheme integrated with the existing wetlands) or a combination thereof.

Provide stormwater quality improvement measures commensurate with the type of development.

Integrate the site stormwater management strategy with the existing adjacent wetlands wherever possible.

Part of the required Stormwater Management Strategy should include an assessment of the required demand / volume for the stormwater to sustain a wetland system and the associated impact of infiltration and evaporation associated with any proposed swales. The Strategy is required to include all of the proposed elements holistically to ensure that they will work effectively and sustainably, and should include: appropriate modelling to ensure the suitable location of inflows, and

potential implications for upstream outfalls; how the new wetland will co-locate with additional tidal flushing; and the general design and special layout of the stormwater system that will

include detention basins, overland flow paths, new tidal wetlands, and traditional stormwater management infrastructure.

Port Adelaide Enfield Council is undertaking Stormwater Management Plans for key major upstream catchments that drain to the Gillman area.

Council is of the view that the development of the Gillman area provides a crucial linkage opportunity in relation to integrating the further research required for flood mitigation, the upstream plan for flood and water quality management, and identifying harvesting and conservation opportunities that could be implemented in the Gillman area.

5.2 Chemically Aggressive Soils

The new Environment Protection (Site Contamination) Amendment Act 2007 came into place on 10 December 2007. Within the definition of the Act, if construction work will affect the acid sulphate soil conditions of the site, then that action is deemed to be contaminating the site. The work will then be bound by the Act and the work will need to manage the resulting contamination.

5.3 Protection from Sea Inundation 5.3.1 Protection Options

Two options are available for the development to be designed in accordance with the Coast Protection Board policy. 1. Levee Option (Council's Preferred Option) Replace existing levee with new levee to a height of 3.7 mAHD.



Levee to extend from the Barker Inlet Wetlands / Cheetham Saltpans boundary to the southern extent of the Defence SA land.

Provide sufficient space along the alignment of the levee to enable this levee to raised in height by a further 0.7m.

Develop the land protected behind the levee (subject to stormwater management and other (environmental) constraints).

Council has indicated its desire to see appropriate further studies with respect to impacts on the coastal environment and eco-systems of the construction of a new levee. It also requires that any new levee should be designed accordingly to ensure prevention of negative impacts on mangrove accession and related fish nursery and other economic / environmental values of the coast in the study area. 2. Fill Option Existing levee to remain. Land developed to a minimum site level of 3.7 mAHD. Provide sufficient space to enable a levee to be constructed to protect

development against a further 0.7m sea level rise.

5.3.2 Condition of Existing Levee The existing levees were constructed in the 1930's when most of the Gillman / Dry Creek area was tidal. As noted in the Ruan Report, there is a lack of information on the design and construction of the existing levee bank and the bank is known to have been breached on at least two occasions in the last 25 years. The Ruan Report also noted that there is a relatively low lying length of existing levee bank located between Grand Trunkway and the drain outlet gate, east of the speed boat club. This section is approximately 0.5m lower than the rest of the levee (approximately 2.4m AHD compared to a general crest level of 2.9 - 3.0m AHD). Based on current figures from the Coastal Management Branch, the majority of the levee (where the crest level is constructed to 2.9-3.0m AHD) provides protection for Gillman against a 1:100 ARI storm tide event together with an allowance for freeboard of between 0 and 100mm as follows: a 1:100 ARI storm tide level of 2.5m AHD; storm wave set-up of 200mm; and storm wave run-up of 200mm. Note that those portions of the levee where the crest level is not constructed to this elevation should be increased to ensure that a consistent level of protection is afforded. Flinders Ports SA has expressed the desire for further detail regarding any levee construction in the vicinity of their land holdings along the Port River. Defence SA is proposing to develop land to the west of Grand Trunkway for industrial purposes and is proposing to raise the ground level to a height of



3.30m AHD. It is understood that, due to lower expected land subsidence in this area compared to land to the east of Grand Trunkway, that this fill height will satisfy the requirements of the Coastal Management Branch of DEH. On this basis, Defence SA has argued that, if the land is filled, there will be no requirement to extend a new levee around the perimeter of its land. Defence SA also supports the preservation of a 3 metre wide corridor of land around the perimeter of its land holdings to permit the future construction of a 700mm high levee wall should further protection from sea water inundation associated with long-term sea level rise be required.

5.3.3 Height of New Levee The recommended height of any new levee is 3.7m AHD. In addition to the allowances included under Section 5.3.2 above, the Coastal Management Branch of DEH is satisfied with the following parameters: predicted short / medium sea level rise of 300mm; long term land subsidence provision of 500mm.

Note that the provision for land subsidence is long term and any subsidence should be monitored. Also note that the design of the sea wall must allow for the construction of an additional height of 700mm to provide for potential long term sea level rise. Figure 6 indicates an appropriate cross section for the new levee, assuming that it is constructed immediately adjacent to the existing levee.

5.4 Filling of Land / Land Subsidence / Earthquake Risk

5.4.1 Overview As outlined in all of the previous reports and studies investigating potential development at Gillman, land suitable for development will need to be filled to a height to: (a) protect development from flooding; and (b) avoid impacts on development and associated underground services from underlying chemically aggressive soils. The creation of an engineered filled embankment platform to provide for future development will need to incorporate pre-loading to reduce the risk of land subsidence, through the inducement of settlement, stiffening and over-consolidation of the foundation soils. Strengthening and stiffening of the foundation soils will also provide a small benefit in terms of earthquake risk by reducing both the likelihood and consequences of soil liquefaction and seismic shaking. Considerable research and detail has been produced on potential methods of filling the land and the recommended fill materials, and these are included in Appendix 2.



FIGURE 6: Indicative Cross Section for New Levee



5.4.2 Land Subsidence It is understood that land in the Port Adelaide region is subsiding over time. However, different parts of the region are subsiding at different rates, and the Gillman area is acknowledged as being an area that has the potential to subside at a faster rate than most other areas. While allowances have been made in parts of Port Adelaide and the Le Fevre Peninsula for subsidence levels of approximately 200mm over the next 50 years, the advice for Gillman is that an allowance of 500mm needs to be provided for over the next 50 year period (refer Ruan Report). Further research on the extent of possible subsidence is recommended, particularly in the context of settlement likely to be induced prior to construction activity through pre-loading works (refer Section 5.4.1 above). As discussed above, pre-loading of areas to be filled may help to compact underlying soils and reduce the overall rate of subsidence somewhat. Given the importance of understanding the rate of subsidence in the Gillman area, a long term monitoring programme will need to be implemented to ascertain the actual rate of subsidence in the area.

5.4.3 Height of Fill

The minimum required fill height for developable land is 2.9m AHD if the land is protected by a levee constructed to a height of 3.7m AHD, or at least 3.7m AHD if a new levee is not constructed. The recommended minimum height of 2.9m AHD for the finished level of the fill embankment has been governed by a number of factors, including the following: a) the minimum requirements for protection of future development against

coastal flooding, particularly in the event of a breach of the existing sea wall based on current sea levels;

b) providing sufficient clean fill depth within which building footings and

underground services can be constructed without being negatively impacted by underlying chemically aggressive soils;

c) providing sufficient clean fill depth to facilitate compaction / settlement of

the underlying soils to reduce long term settlement/ and d) to provide a building construction platform of sufficient height to protect

development from stormwater flooding. 5.4.4 Edge of Fill

In order to reduce the potential impact of earthquake induced lateral spreading of slopes, it is recommended that structures be set back a minimum distance behind the crest of the perimetered batter, as shown in Appendix 2. The edge slope should have a batter of no greater that 1 in 3, and should grassed and landscaped to minimise erosion.



The additional building setback (including underground services) provides an allowance for lateral spreading of fill in the event of earthquake induced liquefaction.

5.5 Provision of Physical Infrastructure 5.5.1 Headworks Requirements

Careful engineering design will be required during the detailed design stage. Services are to remain within the engineered fill wherever possible to eliminate the impact on acid sulphate soils. The SA Water network within close proximity to the site is running at capacity and, as such, cannot accept additional connections. A rising main and storage will be required prior to connection into the Adelaide-Bolivar trunk main. Further discussions with SA Water regarding this connection are considered necessary. SA Water is to provide feedback on their recent network analysis to ascertain the headwork requirements. Council has indicated its strong support for the investigation and analysis into all feasible opportunities for the harvesting and re-use of rainwater at the precinct and site scales throughout the area to supplement water supply and reduce the consumption of mains water. It is also noted that Council will not support the on-site management of sewage or trade waste in any part of the precinct. Power headworks will require a substation on the site including the provision of suitable allotment for the substation. Council also supports the investigation of renewable energy options to reduce reliance on power supplied from non-renewable sources. Origin Energy will usually provide the infrastructure required for gas services dependant on the individual developers needs. No upgrades to communications networks are anticipated for this work. The communications networks will be contacted during the design stage and provided with layouts of the CST.

5.5.2 Impact of Chemically Aggressive Soils

Where acid sulphate soil materials (actual or potential) are present on a site, the EPA recommends that, where practicable, the material should not be disturbed. Sites that contain acid sulphate soil materials need to be managed to avoid adverse environmental impact and risk to human health. Given the need to fill land to be developed and given that filling to an appropriate height will eliminate the negative impacts of acid sulphate soils it is recommended that physical infrastructure be located within the filled material and not be exposed to the chemically aggressive soils below.



Where disturbance of the acid sulphate soil material is unavoidable, the main objective of acid sulphate soil material management is to prevent or minimise the potential for on- and off-site impacts, using the most cost-effective and environmentally sustainable methods. The suitability of management measures will depend on the nature and location of the acid sulphate soil materials. Common management approaches (see Appendix 3) include:

Minimise disturbance or drainage of acid sulphate soil materials Prevent oxidation Minimise oxidation rate and isolate higher risk materials from exposure Contain and treat acid drainage to minimise risk of significant off-site

impacts Provide an agent to neutralise acid as it is produced Separate acid sulphate soil material Hasten oxidation and collection and treatment of acid sulphate leachate Manage stockpiled materials

5.6 Movement Systems 5.6.1 Road

The study area is bound by several roads that provide vehicle access to the Gillman Site, namely: The Port River Expressway via a grade separated intersection at Hanson

Road; Eastern Parade; Grand Trunkway; and potentially, Whicker Road

All of these roads other than Whicker Road are controlled by the Department of Transport (DTEI). DTEI has advised that the design of roads in the Study Area should cater for PBS Level 3A (ie double road trains and B-Triples). Previous investigations and concept planning work undertaken by Ruan Consulting indicated the following proposed road access arrangements within the Study Area: Land west of Magazine Creek accessed only from Grand Trunkway; Land to the east of Magazine Creek accessed via Eastern Parade and

the Port River Expressway at the Hanson Road interchange. All previous discussions and advice from the Department of Transport has indicated that no additional access points will be provided from the Port River Expressway.

This earlier concept planning work did not provide road access connections to proposed industrial areas either side of Magazine Creek.



The earlier Draft Structure Plan Report included a recommendation for such a road connection for two main reasons: To provide linkages between businesses either side of Magazine Creek,

many of whom will have dependencies requiring vehicle trips between them;

Providing such a connection will reduce the number of vehicle trips using Grand Trunkway, and hence reduce the traffic congestion along Eastern Parade.

The QED Pty Ltd Transport Study addressed a range of transport issues, but in particular dealt with the issue of traffic along Grand Trunkway and Eastern Parade and the interaction between this traffic and trains at the at-grade train crossing. In undertaking the various traffic assessments, QED Pty Ltd was asked to base their investigations on Structure Plan Option A from the Draft Report (refer Appendix 4). During the evaluation of the QED Report it has become clearer that, in order to reduce commercial vehicle traffic flows along Grand Trunkway and encourage more of the traffic from the north western parts of the study area directly through to the Port Adelaide Expressway, a more direct road link from Grand Trunkway through to the Hanson Road / Port Adelaide Expressway interchange is required (as per initial Structure Plan Option B detailed in the Draft Report). Such a link fits in better with the views of DTEI who has always regarded this interchange to be the one to focus on. It also avoids the need to introduce a new left turn exit onto the Expressway from the study area, as well as the need to utilise Whicker Road for through traffic purposes. Based on the QED investigations and further evaluation of options, the key features of the preferred road access to / from the study area are as follows:

Restrict the amount of additional vehicular traffic using the Grand

Trunkway / Eastern Parade roadways Provide a direct road link from the northern section of Grand Trunkway

across Magazine Creek to connect with the Hanson Road interchange at the Port Adelaide Expressway

Utilise Whicker Road for local traffic only Incorporate a new left turn exit off the Port Adelaide Expressway into the

development area for east bound traffic just after the Eastern Parade junction.

Provide for left in - left out only movements from Eastern Parade into the new development area.

5.6.2 Rail

Defence SA has recently prepared a detailed structure plan for the land that they own between the Port River and Grand Trunkway. Preliminary investigations undertaken by Maunsell Pty Ltd indicate the potential for an extension of the existing rail line spur northwards through Defence SA land and then looping across Grand Trunkway around the proposed industrial development by the LMC to the east of Grand Trunkway. It is understood that



the proposed loop section to the east of Grand Trunkway would not specifically provide for direct rail - land interchange. The Traffic Impact Assessment report completed by QED Pty Ltd in April 2009 included a commentary about the potential for future rail movements within the study area (a small increase is predicted), as well as making a recommendation that train movements should be managed so as to avoid peak vehicle traffic periods to reduce conflict, particularly at the Grand Trunkway / Eastern Parade intersection. While this is one way of reducing such conflict, shifting more of the vehicular traffic away from this intersection through constructing a new road linking Grand Trunkway through to the Port Adelaide Expressway would also help significantly.

5.6.3 Pedestrian Movement

Previous reports undertaken for the study area and the Port Adelaide Enfield Open Space Plan (2005) prepared by the City of Port Adelaide Enfield seek to provide for improved public accessibility around the Port River and North Arm. In particular, the Open Space Plan recommends the establishment of Wetland Walks which comprise a series of footpaths, boardwalks and other facilities that connect the Range, Magazine Creek and Barker Inlet Wetlands and other associated natural area and habitat corridors. The Kaurna Cultural Heritage Survey (2007) prepared for Council outlines the importance of the Gillman area to the Kaurna people prior to European settlement, indicating how the area was moved through and used for a variety of activities. A pedestrian network could extend from the western end of Moorhouse Road through to the Barker Inlet Wetlands, providing a network of regional significance but also one that can be utilised by future workers in the industrial estates at Gillman. The location of new tidal gates along this pathway system will add interest to the walking experience. It will also be important to ensure that reasonable pedestrian access is provided from within the industrial estates connecting to the "Wetland Walks". The existing levee bank (and any future new one) should provide a continuous pedestrian / cycle link that can be supplemented with other trails within the study area. In addition, all new roads within the study area should have paved pedestrian footpaths located on either side of the roadway to encourage walking.

5.6.4 Cyclists

In order to encourage cyclists to use the area, provision should be made in any upgrading of Grand Trunkway and the Grand Trunkway / Eastern Parade intersection to incorporate on-road cycle lanes that can then link to the proposed "Wetland Trails" around the levee bank connecting the wetland areas. In addition to off-road paths and on-road cycle lanes, the whole of the road network should be designed to promote cycling within the study area.



5.6.5 Public Transport

Provision should be made in the design of the road network for a possible future bus route enabling the local workforce to journey to work by public transport.

5.7 Public Access to Coastal Environments As outlined in Section 5.6.3 the State Government and the City of Port Adelaide Enfield are committed to improving public access to coastal environments. Currently public access to North Arm and North Arm Creek is extremely limited. The only access point is from Club Road which leads to the Adelaide Speed Boat Club facility on North Arm. Earlier studies have identified the desirability of creating a small public park at the end of Moorhouse road at the junction of North Arm with the Port Adelaide River. Providing this and other points of public access provides opportunities for passive recreation, fishing and walkways and cycle ways as part of a network that could link through to the Barker Inlet Wetlands. Furthermore, with the environmental improvement of currently degraded land inland of the levees, improved public access to land adjacent to North Arm could be provided.

5.8 Creation of Sustainable Ecosystems 5.8.1 Introduction of Tidal Flushing

The existing levee bank has isolated intertidal areas on the site. The site has hypersaline groundwater and near the levee is a groundwater discharge area. As a result there is no tidal exchange to flush salt out and the former marine-estuarine sapphires and mangroves have either died or are severely degraded. As indicated in Ruan Consulting (2006), the opportunity exists to reintroduce tidal flows through new tide gates. This would: Allow for the re-establishment of a healthy samphire community and an

area for mangrove recolonisation. Provide some additional habitat for marine and estuarine fauna. Provide improved bird habitat (shallow feeding areas for waders). Improved landscape amenity as a backdrop to the new development. The inundation would mitigate the potential impacts of ASS (refer Ruan

consulting 2006). This suggestion, by Eco Management Services Pty Ltd as part of the Ruan Study Team, was based on: The successful re-establishment of tidal flows into a new marine basin in

the Barker Inlet Wetland. A healthy samphire community has established and mangroves are colonising.

The provision of new areas for samphire accession is a recommendation of the Port Waterways Water Quality Improvement Plan (EPA 2007). With the extent of development in this region and with sea level rise, there are limited areas for landward migration. This is not so much an



issue with mangroves as they can keep pace through sediment accumulation.

Investigations will have to be made on the size of the tide gates, so that sufficient water is allowed to flow in and out on each tidal cycle. Information can be obtained from the existing gates at the Barker Inlet Wetland.

5.8.2 Appropriate Planting Selection

Landscape Areas Attractive landscaping will be required for the development, including grassed areas, shrubs and trees. Although landscaping in the "developed" areas will be located in fill, care will need to be taken due to the salinity of the shallow groundwater. This will involve: Fill/mounds to lift the root zone well above the groundwater. A barrier

may be required to prevent capillary rise. Trees will have a deeper root system than shrubs and bushes, therefore underlying soil conditions will determine the plant selection.

Salt tolerant species could also be selected. A flora database has been developed to assist landscapers in their selection, which identifies a wide range of suitable species for the site (see Eco Management Services, 1997).

Wetlands The establishment of any new wetland areas close to the levee for stormwater purposes, unlike the existing wetlands, should be saline in nature with a plant selection appropriate to the saline conditions. The flora database (EMS, 1997) would also assist identifying suitable species. Observations made by EMS for all three of the Gillman wetlands on the species that have been successfully established in the more saline areas would also be of great assistance, refer EMS (1999 a and b).

5.8.3 Flora and Fauna

Surveys of fauna and flora have previously been undertaken and all information on flora and the site condition collated and summarized in EMS (1997). Information on fauna was collated and reported in EMS 1996. The only major change since that period has been the construction and establishment of the Gillman Wetlands (Magazine Creek, Range and Barker Inlet Wetlands). This information has been revised by Ecological Associates (2006) who were also engaged to undertake targeted surveys for Halosarcia flabelliformis (Bead Samphire or Bead Glasswort) on parts of the Gillman site as this species is listed as vulnerable under the Environment Protection and Biodiversity Conservation Act (EPBC Act 1999). This species had previously been reported on site (EMS 1997). EMS (1997) records 128 plant species, 50 of which are native and 78 are introduced weed species. The main natural vegetation associations on site



are the remnant samphire communities. Within the Gillman site, all species of conservation significance are found within the wetland areas or areas not proposed for development, including the Bead samphire (location shown on Figure 7). The proposed re-introduction of tidal flows will benefit the samphires and Halosarcia flabelliformis which have been reported growing in damper or more flood-prone habitats than other samphire species. Plants could be rescued prior to site development and re-introduced to the new intertidal wetland area. As reported by EMS (1996) all of the fauna recorded on site are common to the region. No rare or endangered species occur and no species is dependent on the site. Approximately 50 bird species were recorded on site. This included three species of conservation significance: the peregrine falcon (Falco peregrinus), the little egret (Ardea gazetta) and the samphire thornbill (Acanthiza iredalei rosinae). The falcon and egret are widespread and would be occasional visitors rather than dependent. The sighting of the thornbill is now seen as unlikely. No native mammals occurred due to the disturbed nature of the site and the presence of feral animals. Few reptiles occurred, but were considered common. No amphibian (frogs) had been previously reported. This has changed with the construction of the Gillman Wetlands. A design objective was to create fauna and flora habitat. This is seen as successful, with approximately 200 bird species, many on international agreements. Although surveys have been undertaken of other groups (mammals, reptiles, amphibian), one mammal species has been seen in the Barker Inlet wetland. This was the Water Rat (Ecological Associates, 2005). The proposed development will not affect any habitat area or species of conservation significance. The existing two wetlands can be avoided, except for the possible replacement in whole or modification of part of the Range Wetland ponds. This, however, may be positive as it will involve new wetland areas. The re-introduction of tidal flows is more likely to increase habitat areas and biodiversity.

5.9 Protection of Coastal Water Quality

In the longer term, coastal water quality will need to be protected by: Maintaining the function of the existing Magazine Creek and Range

Wetlands

As indicated earlier in Section 4.1.2, Magazine Creek Wetland will be maintained. However, the Range Wetland could be replaced or modified as discussed earlier. The important thing is to maintain the overall net pollutant reduction performance.



FIGURE 7: Location of Bead Samphire



The interception and treatment of stormwater runoff from the proposed new development.

All stormwater runoff from the new development, in accordance with WSUD principles (refer section 5.1), should be either intercepted for reuse or appropriately treated in swales and/or detention (wetland) basins. The existing Magazine Creek and Range Wetlands should have the capacity to accommodate the additional runoff volume if stormwater runoff from the development was directed to these existing systems, potentially removing the need for land to be set aside in the development for this purpose.

The development of a Construction Environmental Management Plan (CEMP)

During the construction phase of the project, a CEMP will be required. With regard to protecting water quality it will include a Soil Erosion and Drainage Management Plan and an Acid Sulphate Soils Management Plan.

The development of an Operational Environmental Management and

Maintenance Plan (OEMMP)

This essentially involves the development of a plan for managing the wetlands as part of an ongoing OEMMP, to ensure long-term sustainable performance. This will be particularly important if water is harvested for reuse. Responsibility for such ongoing management is likely to lie with the City of Port Adelaide Enfield.

Overall, the protection of water quality in the Port River-Barker Inlet system is not seen as a major concern with the proposed development.

5.10 Footing Design As detailed in Appendix 2, a filled embankment platform is proposed for all developable areas specifically designed to avoid any impacts from underlying chemically aggressive soils. The depth of fill has been determined taking into account the desire to reduce risk of land subsidence and exposure of acid sulphate soils, and provide sufficient depth for footings and underground services so that the underlying material is not breached. Provided that the fill material and process is designed accordingly, building footings should be shallow raft / pad structures rather than piered footings that penetrate the filled material. However, for facilities that are heavily loaded and / or settlement sensitive deep pile footings may still be required. Research undertaken as part of the Ruan Consulting report has led to recommendations that would ensure that the various soil - structure interaction effects are properly considered, including taking into account the affects of potential earthquake shaking. Examples of techniques to mitigate



the impact of earthquakes include: – building superstructures should be of ductile, flexible construction; – service lines should have flexible joints and connections; – footings should be well reinforced and tied together such as by use of a

grid of ground beams connecting discreet pad footings, or even a single, continuous mat footing.

5.11 On-going Management / Monitoring As outlined throughout this Report, the intention has been to identify land within the Study Area that can be developed for industrial purposes on land protected from natural hazards. In particular, these hazards include protection from stormwater flooding, coastal flooding, the impact of chemically aggressive soils, the impact of potential sea level rise, the impact of land subsidence and, to some extent, the impact of earthquake. The key management / monitoring requirements recommended as part of the development of the land include the following (responsible authority indicated in parenthesis): Monitoring of sea level rise (State Government). Monitoring of ground water levels and quality (LMC). Monitoring of land subsidence(LMC). Monitoring of the condition of the high pressure gas mains (owners of

mains). Monitoring of stormwater quality discharging from wetlands (LMC /

Council). Monitoring of vegetation / habitat development within the stormwater

ponding basin area (LMC / Council). Management of tidal gates to assist with stormwater management and

tidal flushing (Council) Monitoring of new landscaping performance (LMC / Council). Monitoring of the performance of structures (LMC / developers). Management of dust, erosion and odour during construction (LMC). Further information regarding management and monitoring can be found in Section 5 of the Ruan Report.

5.12 Land Use Zoning 5.12.1 Existing Development Plan

Land within the Study Area is located within three zones, namely: The Multi-function Polis (MFP) Zone; The Industry (Resource Recovery) and Coastal Zone; and The General Industry (2) Zone.

The majority of the site lies within the MFP Zone which was created in the 1990's when land within the study area was proposed to form part of a new residential and mixed use Urban Development comprising a range of housing,



business, tourist and industrial uses together with appropriate recreational, cultural and community activities. While industrial development is a "merit" form of development in the MFP Zone, the provisions of the Zone make it clear that the predominant form of development envisaged is for residential. Consequently it has been generally understood that land within the MFP Zone at Gillman should be re-zoned following the completion of appropriate land use and structure planning. With respect to the Industry (RR) and Coastal Management Zone, that part of the zone owned by the LMC lies within the Co-ordinated Development Area Policy Area 47. Again, while land division for industrial purposes and industrial land uses are "merit" forms of development, the Objectives and some of the Principles of Development Control make it clear that development should not take place within the Policy Area until the completion of a comprehensive strategy and management plan that deals with the full range of issues considered in this Report. Therefore it is envisaged that re-zoning of this land will be required following the completion of appropriate land use and structure planning for this part of the study area. The southernmost portion of the site lies within the General Industry (2) Zone. This zoning applies to approximately 4 hectares of the site, and provides for the development of general industry, light industry and associated activities.

5.12.2 Draft Industry Development Plan Amendment by Council

The Port Adelaide Enfield Council prepared a Draft Industry Zones Development Plan Amendment that was released for agency and community consultation in late 2007. The Draft DPA proposed a new “Deferred Industry and Coastal Management Zone” over much of the Study Area. The principal objective of the proposed Zone identifies that the land is to be retained for future industrial development. Many of the proposed Zone objectives and principles of development control seek to highlight constraints to development, which in Council’s opinion require resolution, prior to rezoning the land for industrial use, including: Lack of availability of network infrastructure services. Methods of dealing with seawater and stormwater inundation (and a

combination of both seawater and stormwater inundation), also taking into account anticipated sea level rise.

Constraints to development caused by actual and potential acid sulphate soils.

The need to restore and enhance the inter-tidal ecology both within and adjacent the Zone.

The need to indentify what area within the Zone should be devoted to coastal or other public open space.

The need to determine the extent of potential soil and ground water contamination within the Zone.

Given that studies (including this detailed Structure Plan Report) had already been initiated to address some of these issues, it is understood that the



Minister for Planning and Local Government preferred that these studies be completed prior to initiating a rezoning of this land. It is understood that the land proposed for rezoning to “Deferred Industry and Coastal Management” will continue to retain the MFP zoning until at least the conclusion of this current review.



6 FINAL STRUCTURE PLAN

6.1 Initial Structure Plans

Two Structure Plan options were prepared and incorporated into the Draft Report prepared in February 2008. The main difference between these two options was the alignment of a proposed collector road linking developable areas either side of Grand Trunkway with developable areas to the south of Magazine Creek (refer to Appendix 4).

6.2 Key Amendments Arising from Stakeholder Feedback / Additional Investigations

Following the completion of the Draft Report, stakeholder feedback was obtained and the transport studies commissioned by the Minister for Urban Development and Planning were undertaken by QED Pty Ltd. As a result the following key amendments to the draft Structure Plans are recommended: A Structure Plan generally in accordance with Initial Structure Plan

(Option B), incorporating a collector road directly linking Grand Trunkway through to Port Adelaide Expressway at the Hanson Road interchange.

Changes to the staging of development areas taking into consideration: - the availability of suitable development land owned by Adelaide City

Council within the Industry (ResourceRrecovery) and Coastal Zone; and

- limitations of the existing road network to take projected traffic increases.

6.3 Overview The Final Structure Plan outlined in this Report identifies: Land immediately suitable for development. Land potentially suitable for development. Land not suitable for development.

6.4 Extent of Developable Land - Short Term As outlined in Section 4 the four main factors determining the extent of developable land in the short term include: the land must not be needed now or in the future for flood protection

(both within or external to the Study Area); the land must be able to be protected from coastal flooding taking into

account predicted sea level rise (and a plan put in place to achieve such protection);

development of the land should not degrade coastal waters and eco-systems; and

traffic generated from the areas of land should not significantly compromise the capacity of the existing road system to handle the increase in traffic.



Figure 8 identifies the extent of this land, which comprises approximately 55 hectares in areas generally known as "Lot 3 - Grand Trunkway East" - part only, a portion of the former "Dean Rifle Range headland" and land known as Lots 201 and 202 owned by the Adelaide City Council. The delineation of these areas is based on the following assumptions: Traffic generated from these areas can be accommodated within the

existing road network without significant upgrades. Stormwater quality improvements established either within the

developable area and / or within the areas of existing and future wetland external to the developable area.

Only land above the 1 in 100 year stormwater flood event, together with

adjacent land where only minor volumes of water are accommodated, subject to an equivalent volume of flood storage being available to offset the reduction is developed.

Stormwater ponding area is assumed to exclude any additional area

required to duplicate the existing levee and increase its height (this area is considered to be negligible).

Figure 8 also identifies land owned by Defence SA located on both sides of Moorhouse Road considered suitable for development in the short term (shown with a dotted line).

6.5 Extent of Developable Land - Longer Term

It will be possible to identify additional land (generally in accordance with Figure 5) able to be developed beyond that outlined above, subject to undertaking the works and further flood modelling and mapping identified in Section 5.1. In addition, the creation of additional developable land will be dependent on the following:

If sea level rises with a consequent increase in ground water levels,

stormwater pumping from the ponding basin to the sea may be required to compensate for reduction in ponding volumes (note that such pumping will be required in many other areas of Adelaide to protect developed areas);

An assessment of the impact of providing for adequate tidal flushing

within the ponding areas on ponding volumes / areas; and Undertaking a range of road works upgrades and new road works to

create a road network with sufficient capacity for the traffic generated by all new development areas.



FIGURE 8: Short Term Development Areas



6.6 Additional Investigations to Identify Further Developable Land

In order for all of the potentially developable land to be released, the following additional more detailed investigations are required: Confirmation of stormwater flood ponding levels and impact on upstream

catchments (refer to Section 5.1) Monitoring of rate of settlement of land. Traffic impact assessment. Design of tidal gates / tidal flushing Assessment of impact of sea level rise on ground water levels.

6.7 Final Structure Plan

Figure 9 indicates the Final Structure Plan for the Study Area, assuming all of the land immediately suitable for development together with the potentially developable land is developed. The initial Structure Plan indicates: Developable areas. Road access points and linkages Rail infrastructure. Areas retained for stormwater management, ponding and tidal flushing. The location of a new levee bank and tidal gates. Areas considered desirable for public access. A potential Local Centre to service the daily needs of the workforce.

With potentially over 250 hectares of industrial land available in the area, the range and size of local facilities required to serve the needs of the workforce in the area will need to be determined. Apart from retail facilities, other uses could include a childcare facility, financial / banking institutions, licensed premises, and other similar activities.

6.8 Staging

Figure 10 indicates the indicative staging for the release of land in the short to longer term (assuming all issues are addressed enabling all potential land to be developed). The Figure indicates approximately 252 hectares in total of industrial land, in 6 key development stages. Stage 1 comprises two separate parcels, one of which are currently proposed to be developed by the LMC and the other by Adelaide City Council. The LMC parcel is intended to be subdivided for industrial purposes, while the parcel owned by Adelaide City Council is intended to be developed for resource recovery purposes.



FIGURE 9: Final Structure Plan



FIGURE 10: Indicative Staging of Development



The Stage 1 land release area adjacent to Grand Trunkway is relatively small and it is anticipated that traffic generated by this area can utilise the existing Grand Trunkway road corridor without additional improvements to the transport network. Stage 2 is again in two parcels. The parcel to the south west of the study area close to Eastern Parade is owned by the LMC and would be accessed from Eastern Parade. The area has been limited in size to ensure that traffic volumes accessing Eastern Parade will not place unreasonable expectations on the existing road network. Stage 2 land located within the Industry ( Resource Recovery) and Coastal Management Zone is owned by Adelaide City Council and is available for development, again with vehicular access linking directly to the Port Adelaide Expressway / Hanson Road interchange. In order for Stage 3 areas to be released the new collector road linking Grand Trunkway with the Port Adelaide Expressway would need to be completed. This link provides for the majority of vehicle trips to be via the new collector road rather than via Grand Trunkway / Eastern Parade. With the new collector road in place Stages 4 and 6 can be completed, subject to the identification of the full extent of developable land. It should also be noted that the full aerial extent of Stages 4 and 6 will not be known until the completion of further investigations. With respect to the staging of the new levee bank, it is proposed that a commitment be given to begin construction within 5 years of commencement of Stage 1 and to its completion prior to the release of Stage 4 (using a land fill height of 2.9m AHD). Prior to development approval being sought for Stage 1 a specific commitment for the repair / upgrade of the existing levee should be in place (on advice from the Coastal Management Branch of DEH). Concurrent with the construction of Stage 1 the existing levee bank should be repaired to ensure a continuous height of at least 2.9m AHD along its entire length.



REFERENCES City of Port Adelaide Enfield (2007) Kaurna Cultural Heritage Survey

City of Port Adelaide Enfield (2005) Port Adelaide Enfield Open Space Plan DTEI (2005) Strategic Infrastructure Plan and Regional Overview. URL: http://dtei.sa.gov.au/__data/assets/pdf_file/0019/5194/landmanagement.indd.pdf Ecological Associates (2005) Ecological Values of the Gillman Eco-industrial Precinct. Report to Land Management Corporation, Nov. 2005 Eco Management Services (1999a) Barker Inlet Wetlands. Assessment of the Terrestrial and Aquatic Vegetation Programme. Prepared for Land Management Corporation, February 1999. Eco Management Services (1999b) Magazine Creek and Range Wetlands. Assessment of the Terrestrial and Aquatic Vegetation Programme. Prepared for Land Management Corporation, February 1999. Eco Management Services (1997) Environmental Projects at the MFP Site at Gillman: Vascular Flora Surveys, Flora Database, Vegetation and Habitat Development. Report to MFPDC. Johansen, N and Manning, Paul, (1996) Terrestrial Fauna of the MFP Site at Gillman. Prepared for MFP Australia, May 2006. QED Pty Ltd (20 April 2009): Gillman Dry Creek Traffic Impact Assessment and Access Plan Planning SA (2007) Planning Strategy for Metropolitan Adelaide. URL: http://www.planning.sa.gov.au Ruan Consulting (2006) Gillman Eco-Industrial Precinct, Commonwealth Natural Disaster Mitigation Programme - Final Report: Risk Assessment Study and Concept Design. SA Export Council (2005) Smoothing the Path: Breaking down barriers to export. URL: http://www.southaustralia.biz/library/16_ExpSA_SmoothingThePath.pdf SA Export Council (2004) Beyond Local Towards Global. URL: http://www.southaustralia.biz/library/15_ExpSA_BeyondLocalTowardsGlobal.pdf

APPENDIX 1

Stakeholder Submissions to the Draft Report

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In reply please quote 2002/05389 Enquiries to Phil Lawes Telephone 08 8204 8810 Jensen Planning & Design Unit 6 / 259 Glen Osmond Road Frewville SA 5063 Dear Sir, GILLMAN STRUCTURE PLAN DRAFT REPORT - LMC LAND I refer to your for comments on the Gillman Structure Plan Draft Report prepared for LMC. Thank you for the opportunity to comment. I apologise for the late response. As you may be aware, the State Government CE's Planning and Development Forum has recently considered a proposal for Planning SA to co-ordinate the preparation of a Traffic Impact Assessment and Access Plan of the Gillman area in co-operation with the Land Management Corporation, Defence SA and the Department for Transport, Energy and Infrastructure. In this context the Gillman area essentially incorporates the entire area north of the Port River Expressway and Eastern Parade, and to the west of Hanson Road. The Forum resolved to endorse this proposal. DTEI considers this approach is fundamental to resolve concerns regarding the operations along Eastern Parade resulting from development across the entire area. The work that Jensen Planning & Design has undertaken will be a vital component of this process. Given the above position, DTEI considers that the structure plan for the LMC land can not be formalised in its entirety until the completion of the broader assessment. I recognise this is more a matter for LMC to consider, nevertheless it provides context for the comments below on the draft report. Road Access (Page 26 and 27) The report correctly states that DTEI has previously indicated that no additional access onto the Port River Expressway would be supported. As you would be aware, more recently DTEI has been willing to reconsider this aspect in the context of this structure plan. I nevertheless reaffirm that DTEI does not support the provision of a left-in/out onto the Port River Expressway. Previous investigations have identified that there is insufficient distance

TRANSPORT PLANNING DIVISION Roma Mitchell House 136 North Terrace Adelaide SA 5000 PO Box 1 Walkerville SA 5081

Telephone: 08 8343 2222 Facsimile: 08 8204 8740

ABN 92 366 288 135

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between the ramps for the Eastern Parade and Hanson Road interchanges to allow the required acceleration and deceleration lanes for such an access. The provision of a grade separation on the Port River Expressway at Hanson Road by the State Government (at significant expense) was in no small part to provide a highly functional access into the entire subject area, and thus remove the need for further access points. Importantly, under the AusLink Bilateral Agreement with the Commonwealth Government, the state would need to consult with the Department of Infrastructure Transport Regional Development and Local Government regarding any additional access onto the Expressway. DTEI would also not consider a 'rationalisation' of turning movements at the grade separated intersections. The AusLink network and its connectivity to major arterial roads form the backbone of the road transport system, and hence any 'rationalisation' that undermines the efficiency of this connectivity should not be contemplated. DTEI considers that connection to the existing Hanson Road interchange, and to Eastern Parade through the Dean Rifle Range is the most appropriate approach to the provision of access to the area. DTEI is also very supportive of an 'internal' road connection between the industrial land to the east and west of Magazine Creek, as this would facilitate effective access to the Hanson Road interchange, and remove the dependence upon Grand Trunkway for access to the land on the western side. This access road should also be designed to provide an opportunity for industrial traffic to the west of Grand Trunkway (ie Defence SA land) to access the Hanson Road interchange, in order to enhance access for this area. DTEI would support the potential for an additional access to Eastern Parade at Wicker Road in principle, subject to assessment of the operation of the section of Eastern Parade north of the Expressway. The above structure of access for the area is nevertheless subject to the broader preparation of a Traffic Impact Assessment and Access Plan of the Gillman area by Planning SA. This process will assess the operational capability of Eastern Parade to cater for the increased traffic from the proposed developments across the entire area, in the context of the proposed increased access points, and subsequently confirm or propose alterations to the access structure. Rail (Page 27) Figure 10 shows the rail line as being proposed. There is no proposal to build the line at this time, however a corridor is being preserved to allow for such a proposal in the future. The direction arrow at the bottom of the rail line should be revisited as it points along Evans Street. The collector road which crosses over the rail line could be closed for significant periods of time as trains would need to stop there waiting to access intermodal facilities on the western side of Grand Trunkway, or access to the ARTC network. This aspect will need to be considered as part of the broader study.

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Para 5.6.2 infers that there would be no access to the rail line along Wicker Road. Depending on any redevelopment between Wicker Rd and Grand Trunkway rail access may be required, and should be considered. Pedestrian and Cyclists (Page 27 and 28) DTEI support development of a walking and cycling network in the area. The inclusion of bicycle lanes as part of the improvements to Grand Trunkway is also supported, and this should be extended to include any improvements to the Eastern Parade junctions. Public Transport (Page 28) DTEI supports the design of the road network to allow the movement of buses through the development. It should be noted that there is currently no funding for the provision of services for the new development, and would need to be provided by the developer. Heavy Vehicles The report should recognise that the design of the roads in the area should cater for PBS Level 3A (eg double road trains and B-Triples). Initial Structure Plan Options (Page 42 and 43) In the context of the above comments, and that any structure plan needs to be ratified by the broader preparation of a Traffic Impact Assessment and Access Plan of the Gillman area by Planning SA, DTEI would have a preference for Option B at this time. This option would more likely provide more effective connectivity to the existing interchange at Hanson Road. It is nevertheless recognised that the internal layout of roads in the development is more a matter for LMC and council to consider. I trust this information clarifies DTEI's position. DTEI is keen to continue to input into the development of a structure plan for the entire area, recognising the urgency in the release of a small portion of industrial land to the west of Magazine Creek, and would welcome further discussion as required. Yours faithfully, Mark Elford Director, Road Transport Policy & Planning 26 March 2008 CC Mr Jason Rollinson, Land Management Corporation

Gillman Structure Plan draft report dated 18 February 2008 Prepared by Jensen Planning and Design Comments provided by City of Port Adelaide Enfield Administration ------------------------------------------------------------------------------------------------------------------------ Provided hereunder is a summary of comments provided by City of Port Adelaide Enfield Administration, in response to the draft Jensen Planning and Design Report entitled “Gillman Structure Plan” prepared for the Land Management Corporation, dated 18 February, 2008. Please note that the comments below are preliminary in nature only, based on the limited information contained with the report. Many of the proposals contained within the report are subject to additional detailed investigations, detailed design and further review. Council has focussed its comments on Section 4 and 5 of the report, entitled “How much land can be developed” and “Issues to be addressed to enable development to occur.” Council’s major comment in relation to the Structure Plan report is that before the Gillman Structure Plan report is finalised, a separate Road and Rail network Master Plan needs to be completed. Council considers that no development should occur in the Gillman region until this important body of work has been completed. As stated later in this document, there are currently traffic (road and rail) safety issues in the area that will be exacerbated if any further development occurs without the appropriate road and rail Master Planning. Further comment on this matter is outlined in Section 5.6 (“Movement systems”) below. It should also be noted that the Gillman Structure Plan study was initiated as a means by which a rezone of the land in a development ready state could be supported by Council. The study was to include information based on rigorous investigations that would underpin a rezone of the subject land and allow the smooth transition to a Development Plan Amendment. It is considered imperative that the abovementioned Road and Rail network Master Plan be completed as part of the study, particularly to identify: • which of the immediately developable parts of the land should be released first; • the risks associated with the proposed multiple (rail and road) crossings on Eastern

Parade and appropriate mitigation of the risks; • the impact on Grand Trunkway and Ocean Steamers Road of the proposed road and rail

network and the release of industrial land. 4 HOW MUCH LAND CAN BE DEVELOPED? 4.1 Land Available in the Short Term We note the comment in the report that it is considered that the development of Lot 3 Grand Trunkway Gillman is considered appropriate in the short term for a variety of reasons. As previously stated, Council considers that this land, and other land in this area, would not be considered immediately developable until the appropriate Road and Rail network Master Plan has been completed and its findings fully assessed.

City of Port Adelaide Enfield Page 2 of 7 DRAFT Gillman Structure Plan report – Jensen Planning and Design 17 March, 2008

5 ISSUES TO BE ADDRESSED TO ENABLE DEVELOPMENT TO OCCUR 5.1 Site Stormwater Management A regional stormwater management strategy is supported strongly – again however

further specific studies and investigations would need to be undertaken prior to defining specific location of wetlands or other techniques. The overall Stormwater Management Strategy would be required which as part of the additional investigations to identify further developable land (section 6.5 of the report). This Strategy should include an assessment of the required demand/volume for the stormwater to sustain a wetland system and the associated impact of infiltration and evaporation associated with any proposed swales.

The Stormwater Management Strategy is required to include all of the proposed elements put together to ensure that they will work effectively and sustainably and should include:

: Appropriate modelling to ensure the appropriate location of inflows, and potential

implications for upstream outfalls; How the new wetland will co-locate with additional tidal flushing, and The general design and spatial layout of the Stormwater system that will include

detention basins, overland flow paths, new tidal wetlands, and traditional stormwater management infrastructure.

The pumping of stormwater is not Council’s preferred option however will be considered

where no other options are available. Council is currently undertaking the preparation of Stormwater Management Plans

(SMPs) for key major upstream catchments that drain to the Gillman area. These Plans are now mandatory for all metropolitan catchments, are supported by the State’s Stormwater Management Authority and require a strategic and multi-faceted approach to stormwater management. The development of the Gillman area provides a crucial linkage opportunity in relation to integrating the further research required for flood mitigation, the upstream planning for flood and water quality management, and identifying harvesting and conservation opportunities that could be implemented in the Gillman area, including the creation of new wetlands as is proposed in the Jensen report. The Gillman structure plan and Stormwater Management Plans provide an opportunity to gain co-planning and joint investment benefits.

5.3.2 Height of New Levee Provision of a levee bank is supported and is Council’s preferred option.

Appropriate further studies must be undertaken with respect to impacts on the coastal

environment and ecosystems of this option, and any levee designed accordingly to ensure prevention of negative impacts on mangrove accession and related fish nursery and other economic/environmental values of the coast in the study area.


A regional approach to marine flood defence and site levels rather than site specific management is definitely the supported approach, provided detailed investigation is carried out into the viability of this strategy in terms of adaptability to existing developments.

5.5 Provision of Physical Infrastructure 5.5.1 Headworks Requirements Although mains water is the Report’s preferred option for water supply to the Precinct,

Council also strongly advocates and will require investigations and analysis into all feasible opportunities for the harvesting and re-use of rainwater at precinct and site scales throughout the area, to supplement water supply and reduce the consumption of mains water. Water Sensitive Urban Design practices that ensure maximum water conservation and water quality outcomes must be a key feature of this precinct, as was originally envisaged.

Council will not support the on-site management of sewage or trade waste in any part of

the precinct – disposal to the Bolivar trunk line is required. Connection to a new substation to access power is noted, however, Council would

support the immediate investigation of Renewable Energy Options, including a thorough investigation of an the opportunity to use solar power as backup or additional supply. Also there is no inclusion of co-generation as an option to create energy efficiencies. Co-generators could be developed on a site specific basis or as part of a private precinct partnership arrangement.

While the Report refers to the SA Planning Strategy and the Industrial Land Strategy to support the development of the area, other key strategies should also be key references and drivers, particularly the SA Climate Change Strategy, and the State Government’s legislated greenhouse emission reduction targets. This precinct could be a model precinct for the use of renewable energy sources in an industrial setting, and could provide carbon related commercialisation opportunities for industries attracted to the area.

5.6 Movement Systems Council has previously highlighted significant concerns to LMC, Planning SA (DAC), DTEI and Defence SA about the road and rail arrangements foreshadowed by the LMC Lot 3 land division and other development projects either underway or planned for the Gillman/Port Adelaide area in the vicinity of the Grand Trunkway, Whicker Road, North Arm Road and the Port Expressway. It has been acknowledged that as Grand Trunkway is the only road access to this area of Gillman which together with the Level Crossing at the junction of Eastern Parade and Grand Trunkway it represents a far from ideal situation. When trains are shunting across this junction access to Grand Trunkway can be closed for up to 20 minutes resulting in drivers undertaking a series of dangerous manoeuvres to bypass the junction. Also recently a serious vehicle accident resulted in Grand Trunkway being closed for a number of hours which denied access to and from properties along the Grand Trunkway during that time.


At a meeting held on 31 January 2008 with various Government Departments and Council, it was noted and acknowledged by several attendees that there are a number of separate studies being undertaken, particularly in relation to road and rail, for the area. It is understood by Council that the parties at that meeting agreed that there is a need to coordinate the studies so that there is one agreed approach for the treatment of road and rail in this strategically important location. Council understands that DTEI acknowledged at the meeting, that it would be best placed to coordinate a review of the existing studies being undertaken, and oversee/manage one report that provides a Master Plan of the envisaged Road and Rail network for the area. We understand that DTEI undertook to work with the DAC to coordinate this body of work. Council considers that it is highly desirable that the Road and Rail network Master Plan also consider the pedestrian, cyclist and public transport movements. Further comment on this matter is included in Section 5.6.3 below. Council has previously argued on many occasions for the appropriate Master Planning of the Gillman area prior to any development taking place on strategically located, undeveloped sites such as Gillman, and to that end will continue to advocate for this work to be completed prior to the formal development of the land. 5.6.1 Road Council is of the view that it is inappropriate to indicate a road linkage through Lot 3 Grand Trunkway Gillman without the appropriate Road and Rail network Master Plan taking place, as referred to in Item 5.6 (“Movement Systems”) above. 5.6.2 Rail As outlined in Item 5.6 above, the Master Plan for the movement networks needs to include both road and rail impacts. 5.6.3 Pedestrian Movement It is considered that the sections on pedestrian, cyclist and public transport movements are quite limited. Council considers that it is highly desirable that the pedestrian, cyclist and (if appropriate) public transport movements are included as part of the Road/Rail Masterplan. This is considered important as the nature of the road network and crossings, traffic volumes, etc, will have a significant impact on the ability and desirability of people moving around the area using other than motor vehicle transport.

5.6.4 Cyclists Please refer to Council’s comments at 5.6.3 above.

5.6.5 Public Transport Please refer to Council’s comments at 5.6.3 above.


5.7 Public Access to Coastal Environments Research is required to ensure the location of the proposed new sea gate (for improved

tidal flushing) is optimal in regard to the ecological requirements and coastal processes of the area.

Please consider if the public access networks, particularly pedestrian and cycle paths,

can take advantage of the sea gate locations, to add interest. 5.8.1 Introduction of Tidal Flushing

The proposal to increase and improve tidal flushing of the areas south of the existing levee is strongly supported in principle. The improved biodiversity outcomes would be of both environmental and commercial value to the region. Section 5.1 of these comments provide feedback on the requirement for a Stormwater Management Strategy noting that at Section 6.5 of the report (additional investigations to identify further developable land) a detailed Stormwater Management Strategy is required to include all of the proposed elements put together to ensure that they will work effectively and sustainably. As already mentioned the Stormwater Management Strategy should include:

: Appropriate modelling to ensure the appropriate location of inflows, and potential

implications for upstream outfalls; How the new wetland will co-locate with additional tidal flushing, and The general design and spatial layout of the Stormwater system that will include

detention basins, overland flow paths, new tidal wetlands, and traditional stormwater management infrastructure.

5.8.3 Flora and Fauna The data regarding the presence of species and biodiversity significance provided in the report is significantly out of date, and was mostly done prior to the establishment of the wetlands. The Report states that there are no species of conservation significance in the area. However, several species of birds in the wetlands are covered under international treaties regarding migratory bird protection. A full biodiversity review of the area is required, in order to obtain a current snapshot of the profile of the area, and incorporate that information into the design, landscaping, and ongoing management objectives of the area. 5.11 Ongoing management/monitoring Before the Structure Plan report is finalised, further discussion is required regarding the “responsible authority” under each of the listed management/monitoring items. As an example Council would not be responsible for monitoring of ground water levels and quality, nor would it be responsible for monitoring of land subsidence. Further discussion would be required regarding the responsible authority for the management and monitoring of the stormwater quality discharging from the wetlands and management of tidal gates.


5.12.1 Land Use Zoning The land use of industry, warehousing, storage, transport related activities, waste management/recycling activities would all appear to be potentially acceptable subject to the outcome of the Development Plan Amendment and satisfactory resolution of the transportation and movement network related matters. 5.12.2 Draft Industry Development Plan Amendment by Council Please note that Section 5.12.2 of the draft Detailed Structure Plan no longer accurately reflects the status of the City of Port Adelaide Enfield’s Industry Zones PAR.

Council endorsed an authorisation version of the PAR at its 12 February 2008 meeting. This version of the PAR proposes a rezone of the Gillman area that is, for all intents and purposes, identical to that proposed by the consultation version of this PAR (adjustments were made to the content of the General Industry and Industry (Resource Recovery) and Coastal Management Zones yet the boundaries proposed by the authorisation version of the PAR in the locality the subject of the draft Detailed Structure Plan are identical to those proposed by the consultation version) e. g. sections of land in the study area are proposed to be zoned “Deferred Industry and Coastal Management.”

Consistent with the resolution of Council ratifying the abovementioned endorsement, on 18 February 2008 the authorisation version of the PAR was forwarded to the Minister for Urban Development and Planning (via Planning SA) together with a request that it be approved and made operable. Council awaits a response to this request. 6 INITIAL STRUCTURE PLAN 6.4 Staging We note the staging sections makes mention that: “With respect to the staging of the new

levee bank, it is proposed that a commitment be given to begin construction within 5 years of commencement of stage 1 and to its completion prior to the release of Stage 4 (using a land fill height of 2.9 m AHD).” Council agrees that there may be scope to implement such an idea that (in relation to flood management) provides an approval to commence stage 1 on the proviso that it is tied to a commitment to build the Levee Bank at a future stage. It is noted, however, that the draft report does not provide information concerning the mechanism that should be used to establish such a commitment. Council is of the view that the report should canvass options in respect of this matter and, moreover, that the report should make relevant recommendations. These additions will provide the information required to strengthen a proposal (DPA) to rezone the Gillman area, a pre-requisite for the transition to a development ready state for the subject land.

Council cannot provide any further comment on the staging proposed until the Road and

Rail network Master Plan has been completed and the agreed findings incorporated into the Gillman Structure Plan report. Once this information has been received and incorporated into the report, a more rigorous assessment of proposed staging of the release of the land can be considered.


6.5 Additional investigations to identify further developable land The Report notes that further research will be required regarding assessment of impact

of sea level rise on groundwater levels. This is supported, and should be referred to the appropriate agency to undertake this work.

The other investigations as outlined in this section are also supported.

------------------------------------------------------------------------------------------------------------------------------- Other considerations not mentioned in the draft report Below are some other considerations not mentioned in the report that should be included as part of the final Structure Plan report. Cultural Heritage The area may potentially contain significant Aboriginal sites. Prior to any works on site appropriate Construction Environmental Management Plans should be prepared which would include details of training of construction staff prior to any construction works regarding the identification and handling of aboriginal items, as per the Aboriginal Heritage Act. At the relevant stage appropriate consultation/communications should be undertaken with the Department for Aboriginal Affairs and Reconciliation within the Department of the Premier and Cabinet. Public Open Space In accordance with Council’s Development Plan, there is a requirement for the provision of 12.5% public open space. An opportunity may exist to develop passive recreation/open space nodes at areas of interest to the public such as wetlands, sea gates etc. that would complement walking trails and the bicycle and other pedestrian movement corridors.

FW Draft Report for Gillman Structure Plan - DTED commentsFW: Draft Report for Gillman Structure Plan - DTED commentsFrom: Hancock, Richard (DTED) [[email protected]]Sent: Monday, 17 March 2008 4:27 PMTo: Peter JensenCc: Barker, John (DTED)Subject: FW: Draft Report for Gillman Structure Plan - DTED comments

Thank you for providing the Department of Trade and Economic Development (DTED) with the opportunity to comment on the Gillman Structure Plan Draft Report.DTED supports the draft plan, and considers that it presents a logical and practical strategy for the development and release of industrial land at the site. DTED also supports the draft plan on the basis that it maximises the availability of an important supply of industrial land in an area of strategic industrial importance, whilst maintaining the functionality of the wetlands and ponding basins in the locality.DTED also supports the identification of the Range Wetlands as a possible future

industrial land parcel in the event of the relocation of that wetland.Regarding the two structure plan options provided by the report, DTED notes that

the principal difference between the two is the configuration of the collector road between Grand Trunkway and the Port River Expressway. DTED is not in a position to form a technical opinion on the most suitable location for that road, but would support consideration of the most efficient option to minimise transport costs for business. DTED believes the structure could include indicative timelines for this land becoming available. This would be particularly useful in terms of future industrial land development programming by Government as well as updating the Metropolitan Adelaide Industrial Land Strategy.Overall, DTED supports the direction of the draft structure plan and believes it

will facilitate the development of this strategically important parcel of industrial land. Please contact John Barker of the Planning and Development Unit

on telephone number 8303 2372 (or e-mail: [email protected]) if you have any questions in relation to this matter.Richard HancockManager, Planning and DevelopmentEconomic Analysis and Policy DivisionDepartment of Trade and Economic DevelopmentT – +61 (8) 8303 2453F – +61 (8) 8303 2509M – + 61 0401 125 432Level 10, 178 North TerraceAdelaide, South Australia 5000GPO Box 1264Adelaide, South Australia 5001richard.hancock@state.sa.gov.auwww.southaustralia.bizDISCLAIMER: The information in this e-mail may be confidential and/or legally privileged. It

is intended solely for the addressee. Access to this e-mail by anyone else is unauthorised. If you are not the intended recipient, any disclosure, copying, distribution or any action taken or omitted to be taken in reliance on it, is prohibited and may be unlawful. If you have received this email in error, please

delete it from your system and notify the sender immediately. DTED does not represent, warrant or guarantee that the integrity of this communication has been maintained or that the communication is free of errors, virus or interference.

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RE Draft Report for Gillman Structure PlanFrom: Townsend, Murray (DEH) [[email protected]]Sent: Thursday, 13 March 2008 1:31 PMTo: Peter JensenCc: Allen, Peter (DEH)Subject: RE: Draft Report for Gillman Structure Plan

Peter, My comments on the draft Gillman structure plan follow: I'm generally supportive of the direction taken from a coastal management/coastal hazards perspective, including the chemically aggresive soils

commentary. Section 4.2.1, Mangroves: saltmarsh is a more-at-risk habitat in the Barker Inlet area - mechanisms to increase/preserve saltmarsh, such as controlled flooding would be more beneficial than propagating mangrove forests (Section 5.8.3 reflects this quite well). Section 5.3.2: it would be more correct to say that '... the Coastal Management Branch of DEH is satisfied with the following parameters...' Section 6.4: the construction/upgrading of the levee needs to have specific commitment in place prior to development approval being sought. Regards, Murray.Dr Murray Townsend Manager, Coastal Management [email protected] Tel: +61 (0)8 8124 4879 Fax: +61 (0)8 8124 4920 Mob: 0401 123 684 Department for Environment and Heritage - South Australian Government GPO Box 1047, Adelaide S.A. 5001, AUSTRALIA http://www.environment.sa.gov.au/ The information in this e-mail may be confidential and/or legally privileged. Use or disclosure of the information by anyone other than the intended recipient

is prohibited and may be unlawful. If you have received this e-mail in error, please advise by return e-mail or by telephoning +61 (0)8 8124 4879.

From: Peter Jensen [mailto:[email protected]] Sent: Monday, 18 February 2008 5:08 PMTo: [email protected]; McLachlan, Richard (Defence SA); Forrest,

Barry (Defence SA); [email protected]; [email protected]; [email protected]; [email protected]; Govett, Malcolm (PIRSA); [email protected]; [email protected]; [email protected]; [email protected]; Lipp, Bill (DTEI); Pfennig, Peter (EPA); Townsend, Murray (DEH); Lusis, Mark (DPC); [email protected]; Barker, John (DTED); [email protected]; Lawes, Phil (DTEI); Gehling, Andrew (DFC); [email protected]; Hancock, Richard (DTED)Subject: Draft Report for Gillman Structure Plan

P5907

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From: Govett, Malcolm (PIRSA) [[email protected]] Sent: Monday, 17 March 2008 4:09 PM To: Peter Jensen Subject: Gillman Structure Plan - Comments by Planning SA Dear Peter, The following comments by Planning SA on the draft Gillman Structure Plan are provided for your consideration. The process of consultation during the formulation of the draft Structure Plan is supported. Page 1 – Section 1.1 – the description of the interests of the Port Adelaide Enfield Council could also include the responsibility for the ongoing regulation and control of development within the Gillman area. Page 19 – Section 5.1 – the option of the catchment scale treatment of stormwater is favoured because it would provide the opportunity to be integrated with the existing wetlands and would compliment the selling of any future industrial estates as being environmentally sustainable and eco-friendly. It is acknowledged the option of individual allotment scale harvesting may be attractive due to lower up-front costs but in the medium to longer-term the maintenance and regulatory costs can be significantly higher. Pages 26 & 27 – Section 5.6.1 – there is an existing traffic management issue along Eastern Parade and the intersection with the Grand Trunkway. Concern has been expressed by the local community, primarily through the Council, about the future development of the Gillman area by the LMC and Defence SA and the potential for such development to exacerbate existing traffic congestion. Furthermore, the potential for additional access points onto Eastern Parade (see Figures 10 & 11, pages 42 & 43) may also adversely affect the performance of the road system in the area. The State Government, through the Chief Executives Planning and Development Forum, has agreed to the preparation of a traffic impact assessment and access plan for the Gillman area. The objective of this plan will be to identify the most effective access for the area while minimising the impact upon the existing road network. The formulation of this plan will be coordinated by Planning SA with the involvement of DTEI, LMC, Defence SA and the Port Adelaide Enfield Council. Input will also be sought from Flinders Ports and the Adelaide Council. There are obvious pressures for the timely release of industrial land at Gillman. There is a willingness to work with both the LMC and Defence SA (as the major land owners and developers in the area) and a preparedness to consider opportunities for appropriate portions of land to be released prior to the completion of the traffic access plan, if it becomes necessary. Page 41 – Section 6.6 – more details will need to be provided on the level of services expected to be made available for the local workforce (see Figures 10 & 11). For example, are these services likely to include child care facilities, financial institutions, licensed premises? The final Structure Plan should provide an advanced version of the likely policy framework for the proposed industry zone. If this policy framework is to be clear and unambiguous, especially in respect of the environmental and other issues to be addressed to enable development to occur (e.g. stormwater management, acid sulphate soils, sea inundation, land subsidence, filling of land, public access to coastal environments) then careful thought and a reasonable level of commitment will need to be given to their management over the short and longer-term. Thank you for the opportunity to participate in the consultation process and to provide comment on the draft Structure Plan. Cheers. Malcolm Govett Strategic & Social Planning PLANNING SA Tel 08 8303 0732 Fax 08 8303 0797 [email protected] Level 6, 136 North Terrace ADELAIDE SA 5000 GPO Box 1815 ADELAIDE SA 5001

Page 1 of 2

29/04/2009file://W:\PROJECTS\2007 Numbers\P5907\Final Report - Gillman Structure Plan\Ap...

APPENDIX 2

Land Fill Methods and Materials

Gillman Eco-industrial Precinct, Commonwealth Natural Disaster Mitigation Programme Final Report: Risk Assessment Study & Concept Design

Project No: 1019 Last printed 29/09/2006 11:29:00 AM http://companyweb/1019_V1_Draft_Report/Risk Assessment Report/Document/Stage 2 Reportv2FINAL_060929.doc

55

4.2 Ground Improvement

Existing Ground Conditions Analysis The Stage 1 report detailed the existing ground conditions in some depth based on the investigations conducted by:

• URS Australia for general geotechnical conditions • CSIRO for soil processes and chemical condition.

The key findings from the analysis of the existing ground are:

The low lying nature of the land being susceptible to flooding; the presence of acid sulphate soils with an estimation that more than 72860 tones of sulphuric

acid is stored within the ASS soil profile. Most of the acid is, at present, contained within the site as the low hydraulic gradient and bunding prevents it being discharged into the Barker Inlet at any significant rate.

The design concept involves significant ground improvement resulting from the implementation of a Fill Embankment Platform (strategically placed across the site) and an intrinsically related Acid Sulphate Soils management plan.

Rehabilitation of Low Lying Mono-Sulfidic “Black Ooze” Figure 26 indicates those areas of thick accumulation of mono-sulfidic black ooze (MBO) that have formed in low lying, semi-permanently water logged areas, as identified by CSIRO in the Stage 1 Report. These soils contain only sulfidic material that currently is saturated or maintained below saline or brackish water.

The proposed acquisition of this land for regional open space as indicated in the Concept Plan would allow this land to be treated by the permanent or seasonal re-flooding using an inter-tidal (seawater and stormwater) flushing regime achieved through the installation and operation of gates within the upgraded levee bank. The construction of shallow drains to increase tidal influences to stagnant pools may be required.

The system allows for both:

an open system in which tidal and fluvial inputs occur and are then flushed to the estuary; and a closed pondage system (when required) to stop the export of contaminants to the estuary.

This would allow for the interception and neutralization of any acidic groundwater moving from other areas containing actual ASS and would provide a basin for retaining any heavy metal or other contaminants.

This treatment improves the environmental position of the land by:

Neutralization of actual acidity and reduction of the pyrite oxidation rate Controls any heavy metal contaminants , allows for reductions of Fe, Mn, S and N) and

increases pH level Improving the stormwater quality before it is released to Barker inlet Improving the soil conditions and health of the coastal vegetation by reducing the chances of

eutrophic water conditions forming. Improving the water table height management options that can be used to prevent the

further oxidisation of PASS or further oxidisation of ASS.

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57As part of the risk treatment plan, it is proposed to manage the Range Wetland extension and the Magazine Creek Wetland extension as two discrete and separate bodies so that containment of acid can be managed when needed. This is an important component of the treatment plan to reduce the vulnerability of marine ecological values to the potential impacts from extreme weather events that may erode and mobilise ASS and MBO’s13.

Fill Embankment Platform in Development Areas Figure 27 presents the overall ground improvement plan.

The existing ground surface over those parts of the study area that are proposed to be developed will need to be raised by the construction of an engineered fill embankment platform and pre-loading to:

reduce the risk of terrestrial and coastal flooding, marine erosion, piping and slope instability via a significantly higher finished ground surface compared to the existing ground surface;

reduce the risk of land subsidence, through the inducement of settlement, stiffening and over-consolidation of the foundation soils prior to infrastructure development within the allotments.

The provision of a well compacted fill embankment to act as a thick soil “raft”, together with the strengthening and stiffening of the foundation soils that the fill embankment construction will cause, will also provide a modest benefit in terms of earthquake risk, by reducing both the likelihood and consequences of soil liquefaction and seismic shaking. The potential impact of earthquake induced lateral spreading of slopes will be reduced by setting back allotment infrastructure development minimum distance behind the crest of the perimeter batter, as shown (Figure 28) on the detail for the edge of the fill embankment.

The concept design details for the fill embankment vary depending on the existing ground surface level and the nature of the near surface soils. Two cases have been detailed, these being:

Case A – natural, low lying, non-trafficable land (refer Figure 29); Case B – filled, higher, trafficable land (refer Figure 30).

However, the provision of suitable fill materials that are placed and compacted in layers to form the embankment, and temporary pre-loading of the embankment to improve the existing ground profile, are common to each case.

For both Case A and Case B situations, the resulting fill embankment will be well engineered and, following proof rolling of the fill surface, is expected to be generally suitable to act as a foundation stratum for shallow footings to buildings and other infrastructure, and as a subgrade for floor slabs and pavements. However, for facilities that are heavily loaded and/or settlement sensitive, deep pile footings still would be expected to be required. The detail for the edge of the fill embankment shows that the perimeter batters would have a suitably modest slope to reduce the risk of slope instability and would be vegetated to provide erosion protection against both storm water run-off from the embankment and water that may collect in adjacent low lying ponding areas.

Case A

The fill embankment construction proposed for Case A comprises:

creation of an initial working platform using a geotextile overlain by compacted granular alkaline fill;

followed by a layer of compacted calcareous soil or alkaline fill; a layer of compacted select fill; a compacted granular capillary break layer to achieve the proposed finished level of 2.8 m

AHD; and a final layer of compacted select clayey fill.

13 Sullivan and Bush 2002

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in 0

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th

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tal t

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ness

var

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2.8

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min

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ent b

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g

2 m

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tem

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ener

al fi

ll). S

urch

arge

to

rem

ain

until

prim

ary

cons

olid

atio

n is

com

plet

e (1

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onth

s ty

pica

l),

indu

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sett

lem

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xpec

ted

to b

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0.1-

0.5

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com

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0.

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No

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All

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1 -

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dw

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wo

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5 m

th

ick

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line

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en

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0 d

olo

mit

e s

and

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she

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on

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ck c

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pac

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by

do

zer

me

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no

n-w

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text

ile (

Bid

im A

34

or

sim

ilar)

Sta

ge

3 -

Co

nst

ruct

fill

em

ban

kme

nt

to p

rop

ose

d

f

inis

he

d le

vel

0.5

m t

hic

kca

pill

ary

bre

ak (

coar

se s

and

or

gra

vel)

,p

lace

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nd

co

mp

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in t

wo

0.2

5 m

th

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lifts

by

smo

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m r

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r.

sele

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laye

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lace

d a

nd

com

pac

ted

in 0

.3 m

th

ick

lifts

by

rolle

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ota

l th

ickn

ess

vari

es)

0.5

m t

hic

k la

yer

of

calc

are

ou

sso

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r al

kalin

e f

ill a

s p

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un

de

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laye

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d a

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co

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two

0.2

5 m

th

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by

rolle

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2.8

m A

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min

Sta

ge

4 -

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pro

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re-l

oad

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2 m

th

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ess

of

tem

po

rary

surc

har

ge

(g

en

era

l fill

). S

urc

har

ge

to r

em

ain

un

til p

rim

ary

con

solid

atio

nis

co

mp

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(1

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on

ths

typ

ical

),in

du

ced

se

ttle

me

nt

exp

ect

ed

to

be

0.1

- 0

.8 m

de

pe

nd

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on

com

pre

ssib

ility

of

nat

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lg

rou

nd

pro

file

.

Sta

ge

5 -

Re

inst

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fill

em

ban

kme

nt

to p

rop

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d f

inis

he

d le

vel

Re

mo

ve t

em

po

rary

su

rch

arg

ean

d r

ep

lace

wit

h s

ele

ct f

ill,

pla

ced

an

d c

om

pac

ted

in0

.3 m

th

ick

lifts

by

rolle

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l th

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2.8

m A

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min

nat

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No

tes

1. R

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r to

ove

rall

pla

n o

f co

nce

pt

de

sig

n fo

r lo

cati

on

s w

he

reC

ase

A c

on

dit

ion

s w

ou

ld b

ee

xpe

cte

d t

o b

e p

rese

nt.

2. A

ll fi

ll is

to

be

en

gin

ee

red

so

as

to b

e s

uit

able

to

act

as

a fo

un

dat

ion

stra

tum

for

infr

astr

uct

ure

oth

er

than

he

avily

load

ed

an

d/o

r se

ttle

me

nt

sen

siti

ve f

acili

tie

s.

Dra

win

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:

Cas

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, Hig

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Lan

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on

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du

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Pro

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:

Rev

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No

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62It will be necessary to conduct the fill embankment:

With a significant amount of over-filling of the embankment will be required to allow for this settlement of the compressible existing ground profile.

Sufficiently slowly so that bearing failure of the weak foundation soil is avoided and instead the foundation soil is able to consolidate, stiffen and strengthen under the surcharging effect of each stage of embankment fill placement.

Once the fill embankment material has been constructed up to the top of the capillary break layer, it is proposed to pre-load the fill embankment for each development lot in turn. This would be done by the temporary placement of say 2 m thickness of fill over the embankment platform surface within the lot.

This pre-loading will further consolidate, strengthen and stiffen the foundation soils, and will also reduce the amount of creep settlement of the foundation material beneath the fill embankment (and the amount of creep settlement of the embankment fill itself) that will occur in the long term under embankment self weight and development structural loads. The pre-loading would remain in place until such time as the elastic and primary consolidation settlements of the foundation soils had taken place, which is generally expected to require 1-3 months.

Total settlements under the embankment fill plus temporary pre-load fill are expected to be large and in the range 0.1-0.8 m, depending on the thicknesses and compressibilities of the foundation strata. Once the fill forming the temporary pre-load is removed and shifted to the next development lot to be pre-loaded, the settled surface of the embankment fill within the lot in question will need to be made up again to the proposed minimum finished level of 2.8 m AHD by placing further compacted select fill.

Case B

For Case B, creation of a working platform is unlikely to be necessary to support construction traffic. Rather, non-engineered fill in the form of sandy, hydraulically dredged material is already likely to be present and capable of supporting construction traffic. It is proposed to compact this existing surficial material in place to improve its engineering properties, using a square impact roller.

Once the impact rolling of the existing ground surface has been completed, the ground would be:

filled with a compacted layer of calcareous fill or alkaline soil; and then a compacted granular capillary break layer.

The remaining stages of the fill embankment construction proposed for Case B are similar to that proposed for Case A (i.e. temporary pre-loading, and then reinstating the finished levels of the fill embankment by additional fill placement to make up for the settlements induced in the foundation soils).

Acid Neutralisation The use of alkaline fill material to form any working platform that may be required, and the provision of a calcareous soil or alkaline fill layer near the base of the fill embankment, will provide one means of controlling the potential impacts of acid sulphate soil on the proposed development. This is because should acidic groundwater rise above the base of the fill, due to either consolidation of acid sulphate foundation soils, or capillary rise of acidic groundwater, the alkaline working platform and overlying material will both provide a neutralisation facility. In addition, any overlying clayey select fill will provide a buffering capacity for acidic groundwater. Finally, the granular capillary break layer near the top of the fill embankment will provide a physical barrier that will prevent acidic or saline groundwater from rising further and impacting on development elements founded at or near the proposed finished ground surface, such as shallow footings.

In accordance with the Figure 31, the following materials and depths are recommended to make up the Fill Embankment Platform:

APPENDIX 3

Management of Acid Sulphate Soil Material

MANAGEMENT OF ACID SULPHATE SOIL MATERIAL

• Minimise disturbance or drainage of acid sulphate soil materials

It may be appropriate to select an alternative non-acid sulphate soil site rather than undertake remediation of impacts caused by disturbance of acid sulphate soil materials. If an alternative site is not feasible, works can be designed to minimise the need for excavation or disturbance of acid sulphate soil materials by:

• undertaking shallow excavations and drainage measures. • avoiding lowering of groundwater levels that may result in exposure of soils. • covering the surface with clean soil if acid sulphate soil materials are close to the

surface.

Prevent oxidation This may include staging the project to prevent oxidation and placing potential acid sulphate soil materials into an anaerobic environment, usually below the watertable. Minimise oxidation rate and isolate higher risk materials from exposure This may include covering with soil or water to reduce oxygen availability and control of water movement, or controlling bacteria or other limiting factors (eg alkalinity) by either physical or chemical means to reduce the oxidation rate. Contain and treat acid drainage to minimise risk of significant off-site impacts Typically, this would involve installing a leachate collection and treatment system. Provide an agent to neutralise acid as it is produced This would involve mixing the acid sulphate soil material with an excess of lime. Separate acid sulphate soil material This may include use of mechanical separation, such as sluicing or hydrocyclone to separate acid sulphate fines from non-acidic sulphate material, followed by treatment or disposal of acid sulphate fines in an anaerobic environment. Hasten oxidation and collection and treatment of acid sulphate leachate This involves spreading the acid sulphate soil material in a thin layer over an impermeable area to achieve a high level of oxidation. Rainfall or irrigation leaches the soil and the leachate is then collected and treated. Manage stockpiled materials Stockpiled acid sulphate soil material needs to be managed to ensure no adverse environmental impacts occur. This should include: • minimising the quantity and duration of storage. • minimising the surface area that can be oxidised. • covering the soil to minimise infiltration. • stormwater control measures. • controlling erosion and collection/treatment of runoff.

APPENDIX 4

Draft Structure Plan Options

Draft Structure Plan (Option A)

Draft Structure Plan (Option B)

gillman structure plan - south australia...p5907-final report gillman structure plan.30 april 09 5.5...

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