Report for South Eastern Outfall Extension · 2. Description of the South Eastern Outfall 2 3....

Melbourne Water

Report for South Eastern Outfall Extension

Revised Cost Estimate 2009

March 2009

31/23833/158995 South Eastern Outfall Extension Revised Cost Estimate 2009

Contents

Executive Summary i

1. Background 1

1.1 Introduction 1 1.2 Purpose of this Report 1

2. Description of the South Eastern Outfall 2

3. Design Concept of the South Eastern Outfall Extension 3

3.1 Overall Design Concept 3 3.2 Comparison of Current Options 9 3.3 Previous South Eastern Outfall Extension Options 9

4. Preliminary Environmental, Planning and Cultural Heritage Investigations 11

4.1 Introduction 11 4.2 Approvals 13 4.3 Costs 13

5. Geotechnical Investigations 14

6. Construction Methodology 16

6.1 Overview 16 6.2 Site Mobilisation 16 6.3 Shaft Construction 16 6.4 Tunnel Construction 16 6.5 Marine Works 17 6.6 Purging Structure, Pipeline, Diversion Structure and Odour

Control 17 6.7 Demobilisation 18 6.8 Construction Sequence 18


7. Risk Adjusted Project Cost Estimate 19

7.1 Introduction and Overview 19 7.2 Base Estimate (no allowance for risk) 19 7.3 Inherent Risks 21 7.4 Contingent Risks 21 7.5 Summary of Cost Estimate 22

8. Operation and Maintenance Considerations 23

Table Index Table 7.1 Base Estimates (no allowance for risk) 20 Table 7.2 Risk Adjusted Cost Estimates for Option 1 and

Option 2 22

Figure Index Figure 3-1 Plan Layout of Outfall Extension 4 Figure 3-2 South Eastern Outfall Extension Design Options 5 Figure 3-3 Tunnel Option Diffuser Concept 7 Figure 3-4 Purging Pump Station 8 Figure 4-1 Aerial View of the Site 12

Appendices A Preliminary Environmental, Planning and Cultural Heritage Investigations B Geotechnical Investigations

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Executive Summary

The Eastern Treatment Plant, located in Bangholme south of Melbourne, discharges secondary treated and disinfected effluent into Bass Strait at Boags Rocks on the Mornington Peninsula, via the 57km long South Eastern Outfall which was constructed in the early 1970s.

The Environment Protection Authority (EPA) Victoria issued a works approval in 2003 requiring Melbourne Water to :

Upgrade the treatment plant by implementing

– tertiary filtration and enhanced disinfection to achieve ‘Class A’ standard; and

– ammonia reduction in a modified secondary treatment process

Relocate the discharge point at Boags Rocks offshore by a minimum of 2km

The modified secondary process commenced operation in ammonia reduction mode in 2007, and that part of the works will be completed in 2009/10 with the commissioning of 66% additional aeration tank capacity.

Further studies and tertiary technology trials have been undertaken to determine the optimum path forward for the treatment / outfall options. As part of this process Melbourne Water engaged GHD to prepare an updated cost estimate for the South Eastern Outfall Extension. The cost estimate is based on concept designs developed in 2006.

Two options for the South Eastern Outfall Extension have been developed and costed in this report. Several other options were investigated but then discounted for various reasons. Both options consist of a 2.8 m diameter tunnel extending 2 km offshore and connected to a series of six diffusers located on the seabed. The two options are as follows:

Option 1: A tunnel commencing approximately 80 m back from the shoreline in the Mornington Peninsula National Park at the site of the existing drop structure. The tunnel begins at the base of a 35 m deep shaft and is approximately 2.5 km long.

Option 2: A tunnel commencing in the golf course approximately 800 m back from the shoreline. The tunnel begins at the base of a 25 m deep shaft and is approximately 3.2 km long.

A site area of approximately 150 m x 150 m will be required for the shaft and tunnel works. Environmental investigations have revealed that the site of the works for Option 1 is very sensitive in terms of vegetation and cultural heritage issues. Option 2 does not require any surface works in the environmentally sensitive areas and is, therefore, the preferred option.

Key aspects of the design and construction include:

A 2.8 m diameter segmentally lined concrete tunnel to be constructed using a tunnel boring machine

Minimum 10 m diameter shaft constructed using a diaphragm wall technique

Cross passage construction at end of tunnel to link with risers and diffusers

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Risers and diffusers installed using a jack-up barge and drilling spread

A purging structure and pipeline to remove saline intrusion during periods of low or zero flow

A diversion structure to connect to the existing South Eastern Outfall

Limited geotechnical information is currently available for the site. Consequently, if the project proceeds, a detailed geotechnical investigation will be required. This will include onshore, horizontal core drilling and offshore works and has been detailed in the report.

A six year project timeframe has been envisaged, starting in 2010. The first two years involve environmental and project approvals, geotechnical investigations and detailed design. A four year construction and commissioning period has then been allowed for.

A risk adjusted nominal estimate (RANE) was developed for both options. This process involved determining a base estimate and then assessing inherent and contingent risks as part of a risk analysis process. The @RISK software package was then used to determine the final cost estimates. These are presented in the table below for both options.

Risk Adjusted Escalated Cost Estimates ($M) Option Total Escalated Project Cost

($M) P95 P50 P5

Option 1 351 403 382 362

Option 2 369 422 399 378


1. Background

1.1 Introduction The Eastern Treatment Plant treats approximately 40% of Melbourne’s sewage from the southern and eastern suburbs to secondary treated and disinfected standard.

The Eastern Treatment Plant (ETP) is located in Bangholme south of Melbourne and treated effluent discharges into Bass Strait at Boags Rocks on the Mornington Peninsula, via the 57km long South Eastern Outfall (SEO), which was constructed in the early 1970s.

The existing outfall extends some 30m into the surf below the low water level.

The Environment Protection Authority (EPA) Victoria issued a works approval in 2003 requiring Melbourne Water to :

Upgrade the treatment plant by implementing

– tertiary filtration and enhanced disinfection to achieve ‘Class A’ standard; and

– ammonia reduction in a modified secondary treatment process

Relocate the discharge point at Boags Rocks offshore by a minimum of 2km

The modified secondary process commenced operation in ammonia reduction mode in 2007, and that part of the works will be completed in 2009/10 with the commissioning of 66% additional aeration tank capacity.

Further studies and tertiary technology trials have been undertaken to determine the optimum path forward for the treatment / outfall options. As part of this process Melbourne Water engaged GHD to prepare an updated cost estimate for the South Eastern Outfall Extension. The cost estimate is based on concept designs developed in 2006.

1.2 Purpose of this Report The purpose of this report is to :

Prepare a cost estimate for the SEO extension based on concept designs developed in 2006

Describe the basis for selecting these design options including what other alternative options have been investigated

Outline the environmental impacts of the project and the geotechnical investigations required

Identify key risks that may impact on the cost estimate and prepare a risk adjusted nominal estimate (RANE).


2. Description of the South Eastern Outfall

Under existing conditions, the average dry weather flow treated at ETP is approximately 330 – 360 ML/day. Although wet weather flow into the plant can reach a peak of approximately 1700 ML/day (20 kL/s), the treated effluent holding basins are used to store peak flows, allowing the capacity of the outfall pumping station (OPS) and associated rising main to be somewhat smaller than the influent pumping station. The maximum flow discharged from ETP under peak wet weather conditions is 700 ML/day (8.1 kL/s), less any process water diversion (typically 30-40 ML/day).

The treated effluent flow rate ranges from 3.2 to 8.1 kL/s depending on the number of outfall pumps operating. The effluent from ETP is initially pumped up a 2.1 m diameter rising main for approximately 10.3 km, which forms the first part of the SEO. From there it flows under gravity to Boags Rocks. The final section of the outfall is a 1.8 m diameter pipe. The elements of the existing SEO can be summarised as follows :

OPS comprising 5 pumps, located at ETP

Rising main. 10.3 km long, 2.1 m diameter, commencing at the OPS

Gravity conduit from the downstream end of the rising main to Boags Rocks. The conduit is 47 km long and comprises sections of pipeline and tunnel.

Gravity pipeline sections are generally 2.3 m diameter

There are 4 gravity tunnel sections, typically 3.2 m diameter

The two longest tunnels are at Dromana (7 km long) and at Frankston (5.2 km long)

Outfall structure that extends into the surf at Boags Rocks, discharging below the low water mark.

South East Water Limited (SEWL) has three sewage treatment plants at Mt Martha, Somers and Boneo that discharge into the SEO. The Somers plant discharges at Mt Martha. The average dry weather flow into the SEO from these plants is approximately 22ML/day.

The maximum theoretical capacity of the existing gravity conduit pipelines is 10 kL/s. However, in order to achieve this flow rate, the operation of a fourth pump set in the OPS is required as well as the “duplication” of portions of the existing rising main with a smaller diameter main. The augmentation of the SEO would only be required if there was significant growth in flows. Such an increase would generally be driven by a population increase.

The flow rate, i.e. the peak and variability, is a prime design input for the SEO Extension. For the purposes of this report the maximum flow rate adopted for the design of the extension is 10 kL/s, matching the current gravity conduit capacity.

During maintenance periods, the flow rate from ETP is reduced to zero for short durations of up to 24 hours. Should in the future a very large scale high end recycling scheme be implemented utilising dry weather flows from ETP, this could result in flows in the SEO being reduced to near zero for extended periods of time particularly in the summer months. Some flows from the SEWL plants may remain.


3. Design Concept of the South Eastern Outfall Extension

3.1 Overall Design Concept The SEO Extension concept is to discharge the effluent into Bass Strait via multiple diffuser heads at a seawater depth of 20 to 30 m approximately 2km offshore. The concept is shown in Figures 3-1 and 3-2. In order to achieve this, several key elements are required including a conduit (tunnel) starting at an on-shore shaft, a diversion structure to divert the flow from the existing SEO into the shaft, multiple diffuser heads anchored to the seabed with ports and risers to link the tunnel to each of the diffuser heads.

3.1.1 Segmental Lined Tunnel and Shaft

Three different arrangements for the tunnel have been identified, each of which comprise a segmentally lined concrete tunnel of 2.8 m internal diameter. This diameter is considered the smallest practical size for a tunnel of this type and can accommodate the maximum design flow rate of 10kL/s. The options are as follows:

Option 1 which involves a shorter “downward sloping” tunnel, starting close to the shore in the Mornington Peninsula National Park

Option 2 which involves a longer “downward sloping” tunnel, starting in the golf course, thereby reducing the impact of construction activities on the more sensitive environmental areas

Option 3 which involves a shorter “upward sloping” tunnel, starting from a deeper shaft close to the shore in the National Park (same location as Option 1)

The relative merits of the three options are discussed further below.

The tunnel in all three options starts at the bottom of a minimum 10 m diameter shaft. The depth of the shaft varies between options as can be seen in Figure 3-2. The shaft is required to be constructed before the tunnel can commence. Various construction techniques could be used depending on the geotechnical conditions. For the purposes of this cost estimate it has been assumed the construction technique used will be “diaphragm wall”, which is better suited to generally poor ground conditions than, say, the secant pile technique. The assumed thickness of the diaphragm wall is 1 m. The upper part of the shaft will accommodate the purging pump station, as described below.

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CLIENTS PEOPLE PERFORMANCE

Level 8, 180 Lonsdale Street Melbourne VIC 3000 Australia T 61 3 8687 8000 F 61 3 8687 8111 E [email protected] W www.ghd.com.au

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3.1.2 Diffusers, Risers and Cross Passages

The risers and diffusers are detailed in Figure 3-3. The number and spacing of the diffusers arises from hydrodynamic modelling of the ocean and the initial dilution required by EPA Victoria of 50:1. The modelling indicated the need for 6 diffusers, each comprising 8 number 400 mm diameter ports. The ports do not have valves. The risers are evenly spaced over the length of approximately 360m long with diffusers located in water approximately 20 to 30 m deep. It is important to note that further hydrodynamic modelling will be required to confirm the location and number of ports and risers and has been allowed for in the environmental approval cost estimate.

The risers comprise vertical “tubes” of 1.2 m in diameter. They are fabricated from glass reinforced plastic (GRP) and are installed into a hole drilled from a jack-up barge. Each riser is linked to the tunnel by a cross passage which may be 10 to 20 m long depending on tolerances. For the cost estimate, 20 m has been allowed. The cross passages are constructed from within the tunnel and then connected to the risers and diffusers.

3.1.3 The Seawater Purging Structure and Purging Pipeline

During periods of low or zero flow in the SEO saline intrusion into the outfall extension will occur. These periods could be due to maintenance or the implementation of a large scale recycling scheme. Saline intrusion is undesirable as it creates an additional driving head and requires a significant flow rate above normal to purge the intrusions. In addition, saline intrusion can lead to marine and other growths in the tunnel and risers which can adversely affect performance.

The extent of saline intrusion is significantly reduced by having a tunnel that slopes upwards to the seabed (Options 1 & 2). Saline intrusion will still occur, however, with all tunnel options.

To address this issue a purging structure and associated purging pipeline are required, refer to Figure 3-4. The purging structure is located above the shaft and contains a pump station with flow bypass facilities. The purging pipeline is, nominally, 900 mm in diameter. It starts in the purging structure, is aligned within the tunnel and ends at the start of each of the cross passages.

As described above, the maximum flow rate in the SEO adopted for this report is 10 kL/s. The “excess” or available pressure head at the coastline is not sufficient to discharge 10 kL/s into Bass Strait via the SEO Extension. For this flow rate, pumps are required, although the pumping head is relatively low, i.e. less than 1 m.

The concept design of the purging structure allows for the potential flow upgrade (from 8.1 to 10 kL/s) by incorporating into the building (civil works) locations where ultra-low head pumps could be readily installed at the time of the flow upgrade, should it be required. The cost of the ultra-low head pumps has not been included in the cost estimate.



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3.1.4 Diversion Structure

In order to divert the water from the SEO to the Outfall Extension, a diversion structure is required. The diversion structure will be located at the existing SEO and close to the shaft and, in essence comprises a large concrete junction pit with penstocks. The diversion structure is a subsurface structure similar to the existing drop pits in the SEO, one of which is located approximately 80 m from the coast. As described above, the flow in the SEO can be turned off for short periods (up to 24 hours) which will allow the construction integration to occur.

3.1.5 Odour Control Facilities

The purging and diversion structures are located in a socially and environmentally sensitive area. To address associated odour risks an odour control facility has been allowed for. Due to its location, this facility cannot generate a waste stream limiting the normal range of odour treatment options. Possible technologies include a catalytic oxidation unit or an activated carbon filtration system. The odour control facility would need to take into consideration visual amenity.

3.2 Comparison of Current Options When compared to Options 1 and 2, Option 3 has the following key disadvantages :

Saline intrusion during periods of zero flow would fill the entire tunnel. Purging this much larger volume of sea water would require significantly more purging pumping, and the purging pumping head would be higher.

During the construction phase, if poor rock conditions require the tunnel boring machine (TBM) to be pressurised, Option 3 will require higher pressures for longer. The TBM operators would be exposed to these higher pressures.

Option 3 requires a much deeper shaft i.e. 73 m as compared to 35 m (Option 1) or 25 m (Option 2)

If the tunnel was ever to require dewatering this would be a more straightforward operation for Option 3, however, this advantage is not considered significant.

On the basis of the above reasoning, Option 3 was eliminated from further analysis.

3.3 Previous South Eastern Outfall Extension Options Options for the SEO extension that were identified in various prior reports, but which have been discounted and not examined in this cost estimate, with brief comments on the reason for their exclusion include :

A single pipeline (2.3 m diameter, steel) installed using bottom tow techniques. This option was not considered because of the difficulties, and risk, of constructing large pipelines through the surf zone in this high energy coast line. Where this has been undertaken, for example the outfall at Black Rock south of Geelong, the pipeline was preassembled in strings on land and in line with the proposed alignment. This method would also involve substantial disruption to the sensitive environmental foreshore area. For these reasons this option was not progressed.


Twin pipelines (2.1 m diameter, steel) installed using bottom tow techniques. This option was not considered for similar reasons to the single pipeline.

Multiple small bore outlets, i.e. Horizontal Directionally Drilled (HDD) tunnels. This option was not considered because it is considered to be either at, or beyond the scope of current technology for the length required.

Additional storage. By providing additional storage at ETP or at locations along the SEO it may be theoretically possible to reduce the design peak flow rate. This option was discounted because the tunnel diameter of 2.8 m, as adopted in this estimate, is considered the smallest practical diameter for this type of tunnel. There is, therefore, no benefit in reducing the peak flow by providing additional storage. There is also insufficient storage area available to significantly reduce peak sizing of the outfall extension.


4. Preliminary Environmental, Planning and Cultural Heritage Investigations

4.1 Introduction An aerial view of the area indicating the main onshore works location for both options is shown in Fig 4-1. Appendix A contains an outline of the potential environmental impacts of the project, and its associated geotechnical investigations, and an assessment of approvals that may be required. A brief summary of the environmental, planning, and cultural heritage issues is included below.

The key issues related to the terrestrial environment include :

The cliff and dune system are of high significance, in terms of vegetation, habitat and archaeological assets present;

The area “behind” the dunes (i.e. where Option 1 would require a significant construction site) contains extensive aboriginal middens of high cultural significance and a detailed archaeological field survey would be required;

For Option 1, net gain offsets for vegetation removal associated with the construction site and access road widening would be required. This vegetation is of high conservation significance and net gain offsets may be difficult to find; and

For Option 2, disturbance to the native vegetation is substantially less than for Option 1 and limited to the golf course area, i.e. where the vegetation is of much lower conservation significance.

The key points about the marine environment are:

Ecological surveys of the marine environment have been undertaken;

Construction impacts on the marine ecology are expected to be relatively short-lived and small in geographic extent; and

Any seismic surveys for geotechnical investigations will need to be undertaken using the Environment Protection and Biodiversity Conservation (EPBC) Act Policy No 2 to minimise the impacts of seismic surveys on cetaceans.



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4.2 Approvals Environmental, planning and cultural heritage approvals will all be required under Commonwealth, State and local government legislation.

Environmental A referral will need to be made to the Commonwealth under the EPBC Act 1999 outlining the potential impacts of the project on matters of National Environmental Significance. Any additional approvals required under the EPBC Act may be undertaken in conjunction with any Victorian approvals.

An Environmental Effects Statement (EES) has been assumed to be required under the Environmental Effects Act 1987 as this is a significant project. A referral will need to be made to the Minister for Planning to determine whether an EES is required or not. Such a referral needs to be sufficiently detailed to allow for a decision to be made. As such, considerable work is required to inform the referral.

Under the Environment Protection Act 1970 a licence to discharge at the location will be required.

Consent will be required under the Coastal Management Act 1995 in order to carry out works in coastal Crown land (onshore and offshore).

Planning Planning approval is likely to be required for the proposal, including the removal of native vegetation, pursuant to the Planning and Environment Act 1987. The proposed works are subject to the Mornington Peninsula Planning Scheme.

Cultural Heritage

It is likely that a Cultural Heritage Management Plan (CHMP) under the Aboriginal Heritage Act 2006, will be required for the proposed works. At present there is no Registered Aboriginal Party (RAP) for the locality, therefore a CHMP would be determined by Aboriginal Affairs Victoria (AAV). An assessment by a suitably qualified heritage consultant will need to be carried out, to determine the potential impact of the proposal on cultural heritage. Option 1 is anticipated to involve disturbance of the ground in an area of high archaeological sensitivity.

4.3 Costs The estimated cost of the environmental investigations and approvals is :

Option 1 : $5.5 million

Option 2 : $4.2 million

The cost estimate does not include the cost of on-going compliance monitoring of the outfall.

As Option 2 does not require any surface works within the environmentally sensitive areas it is the preferred option.


5. Geotechnical Investigations

Both onshore and offshore geotechnical investigations will be required. The onshore geotechnical investigations will consist of a vertical bore at the shaft location. Horizontal core drilling (HCD) will also be carried out along the tunnel alignment. Horizontal cores provide useful information with regard to identifying areas of broken rock that may not be picked up by a series of vertical boreholes.

For Option 1, one construction site will be required at the last existing drop structure, which is behind the dunes, i.e. where the shaft will be constructed. The HCD exercise will commence at this location.

For Option 2, which has the advantage of not undertaking permanent works between the coast and the golf course, starting a HCD investigation at the Option 1 shaft location would involve additional vegetation clearance in a high conservation significance area. The HCD investigation is planned to commence at the golf course construction area. The Option 2 HCD investigation alignment will not be able to extend the full length of the tunnel, even if it attains the identified length of 2000 m.

The detailed geotechnical investigations required for Option 1 and Option 2 are outlined in Appendix B, and a summary of those investigations is included below. There would be three “stages” of investigations comprising :

Stage 1 : Onshore Geotechnical Investigations

– For Option 1, this comprises one borehole at the location of the Option 1 shaft, which is behind the dunes

– For Option 2, this comprises one borehole at the location of the Option 2 shaft, i.e. at the golf course

Stage 2 : Horizontal Core Drilling (HCD) Investigations

– For Option 1 the HCD investigation starts at the Option 1 shaft location and extends out to sea along the tunnel alignment for approximately 2000 m. The investigation would obtain information on the hardness of the rock, the presence of any joints, faults and dykes for approximately 80% of the tunnel length.

– For Option 2 the HCD investigation starts at the Option 2 shaft location, i.e. at the golf course and extends out to sea along the tunnel alignment for approximately 2000 m. The investigation would obtain information on the hardness of the rock, the presence of any joints, faults and dykes for approximately 60% of the tunnel length.

Stage 3 : Offshore Investigations, which are common to both Option 1 and Option 2 including:

– sub-bottom profiling using an acoustic signalling system to assess the ground material close to the seabed,

– bottom seismic refraction data acquisition using a seismic airgun and

– borehole investigations, i.e. up to 10 boreholes drilled from a jack-up barge with associated laboratory tests.


The estimated cost of each of these stages is presented. It should be noted that the estimated cost of the identified geotechnical investigations is the same for both Options. This is because the only difference is the location of the HCD investigation, i.e. for Option 1 it would start behind the dunes, and for Option 2, it would start at the golf course. The estimated cost of the identified geotechnical investigations is as follows :

Stage 1 : Onshore Investigations $0.45 million

Stage 2: HCD Geotechnical Investigations $13.35 million

Stage 3 : Offshore Geotechnical Investigations $7.95 million

Total $21.75 million


6. Construction Methodology

6.1 Overview GHD engaged Evans & Peck to prepare the cost estimate of the Option 1 and Option 2 concept designs described above. This required development of a construction methodology and program. A six year project timeframe has been envisaged, commencing in January 2010 and finishing in December 2015. The first two years involve environmental investigations and project approvals, geotechnical investigations and detailed design. A four year construction and commissioning period has then been allowed for. The preparation of the construction program has taken into account the absence of geotechnical investigation data at this stage.

6.2 Site Mobilisation Site mobilisation and construction planning is estimated to take some three months before the excavation works commence with a 12 month lead time to procure the Tunnel Boring Machine (TBM). A work site of 150 m x 150 m at the location of the shaft has been assumed. For Option 1 this will be approximately 80 m back from the shoreline at the site of the existing drop structure. For Option 2 it has been assumed land will be leased from the golf course. In order to manage the Option 1 construction site it has also been assumed a “handling” site will be leased at the golf course.

A site access road will need to be constructed. For Option 1 this will involve upgrading and widening the existing access track. Supply of high voltage power has been allowed for from Rosebud commercial centre.

Wastewater produced at the site will be transported to Boneo Wastewater Treatment Plant for disposal. Wastewater at the site is expected to arise from various activities including dewatering the shaft, dewatering the tunnel spoil prior to disposal off site and the site office.

6.3 Shaft Construction The shaft will be constructed using a diaphragm wall technique to a depth of 35 m for Option 1 and 25 m for Option 2. The wall has been assumed to be 1 m thick and constructed in segments around the circumference of the shaft. The base of the shaft will be grouted and an opening secured for the TBM. An acoustic enclosure will be installed over the top of the shaft. The visual impact of the enclosure during construction will need to be considered.

6.4 Tunnel Construction The tunnel will be excavated using a TBM from a launching chamber at the shaft base. It is assumed the geotechnical information described above will be available to inform the selection of a TBM suited to the actual conditions. For this estimate a slurry TBM with equipment to provide 6 bar of pressure has been assumed.


The TBM will start its excavation and continue for some 2,486 m from the launching chamber in the case of Option 1 and 3,223 m for Option 2. The adopted rate of advance for the tunnel is 54 m per week. The erection of the precast liners will proceed with probe drilling carried out every 15 m of advance. The TBM will be driven to the end of the tunnel, stripped, cleaned and grouted in, i.e. buried.

Access for pick replacement will be done under compressed air. The pick replacement locations offshore will be pre-grouted using the marine equipment. At the seaward end of the tunnel, six risers are to be constructed at a 20 m offset from the tunnel. At each riser location it is proposed to freeze the ground to enable safe excavation. Traditional hand excavation techniques will be used to connect to the risers.

6.5 Marine Works Marine equipment including a jack-up barge and drilling spread to operate in a 25-30 m depth of water will be mobilised along with the associated tug and support vessels. It is assumed a marine yard and associated wharf will be located in Westernport Bay and will be utilised by the project construction company to service the jack-up barge, including personnel access. The precast elements for the riser heads may need to be loaded, and towed to the site from Geelong due to load limitations at facilities in Westernport Bay. If this is the case, then the quarantine provisions that relate to marine pests will be complied with.

Pre-grouting will be carried out from the jack-up barge at designated locations along the tunnel alignment to secure locations for the TBM pick changes.

From the jack-up barge the 2 m diameter holes for the six risers will be drilled, a pipe riser inserted and grouted. It has been assumed that spoil from the risers will be transported to the marine yard for land based disposal. Sea bed excavation for GRP liner and precast riser plug installations, backfill and rock armour placement with assistance from diving crews will be performed. A marine utilisation factor of 40% has been assumed for working conditions in Bass Strait. The total duration assumed for the jack-up barge and marine spread is 33 months.

6.6 Purging Structure, Pipeline, Diversion Structure and Odour Control The purging structure, diversion structure and odour control units will be located either above or adjacent to the shaft.

Construction sequence of the diversion structure will require careful planning. The flow in the SEO will need to be turned off for, say, 24 hours while those parts of the structure directly affected by the flow, which may comprise precast elements, are placed in position.

The shaft will probably be constructed using the diaphragm wall technique, which is suited to generally poor geotechnical conditions. The base of the shaft will probably require grouting to resist high pressure water ingress. A launching chamber or “back shunt” will then be constructed laterally from the base of the shaft to accommodate the TBM.


The purging pump station will be constructed after completion of the tunnel because it is located above the shaft. Other designs are possible. The walls of the pump stations will most likely be constructed using the diaphragm wall technique.

6.7 Demobilisation All marine, shaft and tunnel plant equipment and other resources will be demobilised.

6.8 Construction Sequence Some aspects of the tunnel and riser construction are required to be undertaken in a particular sequence and this is described below, in sequence.

Using the jack-up barge, pre-grout the designated zones where TBM cutters will need to be changed. Grouting must be compete before TBM arrives at each grout zone

Using the jack-up barge start the riser construction

After the shaft and launch chamber (back shunt) are complete, and the TBM has been assembled, drive tunnel to beyond the end of the design alignment, strip TBM and bury the remains at the end of the tunnel in mass concrete

Remove TBM support services from the tunnel

Complete riser No 1 and diffuser head No 1 and seal it safely

Commence cross-passage No.1, after riser No. 1 is safely sealed

Progress the other 5 risers and cross-passages in this manner until all risers are compete and all cross-passages are complete. Cross-passage No. 6 will be last of these activities

Install purging pipeline in the shaft and tunnel

Remove all construction services from the tunnel and shaft and make ready for flooding

Start constructing the purging structure, which is located above the shaft, proceed to completion. It is assumed that the head of the shaft is dedicated to supporting the tunnel and cross-passage construction activities while these are being undertaken.

Flood the tunnel by opening valves in riser plugs via use of divers

Using a boat (not the jack-up barge) remove the plugs from the risers

Construct diversion structure and use penstocks to direct flow to existing outfall. This activity can proceed independently, but needs to be done before the Outfall Extension is commissioned

When the purging structure is complete AND all the risers are unplugged use the penstocks in the diversion structure to divert treated effluent in the SEO into the Outfall Extension

Commission purging pump station


7. Risk Adjusted Project Cost Estimate

7.1 Introduction and Overview The project costing prepared by Evans & Peck for both Options 1 & 2 covers the following areas:

Project costs which include:

– Mobilisation and demobilisation

– Shaft construction and tunnel access

– Tunnel construction and cross passages

– Marine works, i.e. risers & diffusers

– Purging structure/pipeline and odour control

– Diversion structure

– Site overheads and insurances

– Contractors margin

– Land acquisition

– Geotechnical investigations

– Design and consultant costs

– Procurement costs

– Project facilitation costs

– Environmental investigations and approvals

– Project management and administration

– Approvals, legal and communication costs

– Escalation

Inherent risk items which deal with uncertainties in scope, quantities or unit cost rates

Contingent risk items which deal with the validity of project assumptions and unforeseen or catastrophic events

7.2 Base Estimate (no allowance for risk) On the basis of the construction methodology, a base estimate was developed which was used as a starting point for the risk adjustments. The base estimate is presented in Table 7.1.


Table 7.1 Base Estimates (no allowance for risk)

Item Description Option 1 Base Estimate Short Tunnel

($M)

Option 2 Base Estimate Long Tunnel

($M)

1 Mobilisation and Demobilisation 11.1 10.1

2 Shaft Construction and tunnel access 6.4 5.3

3 Tunnel Construction and riser cross passages 73.8 82.1

4 Marine, riser, diffuser construction and grouting 35.9 38.8

5 Purge Structure & Pipeline including odour control 17.9 19.8

6 Connection to Existing Outfall 5.5 5.5

7 Site Overheads, insurances, securities & interest 37.1 38.1

8 Contractor’s margin (corporate overheads & profit) 28.1 29.9

9 Land Acquisition 0.4 0.4

10 Geotechnical Investigations 21.7 21.7

11 Design & Consultant Costs 21.1 22.7

12 Procurement Costs 1.5 1.6

13 Project Facilitation Costs 1.5 1.6

14 Environmental Investigations & Approvals 5.5 4.2

15 Project Management & Administration 3.5 3.5

16 Approvals, legal & communication costs 3.0 3.0

17 Escalation Calculation (Jan 2009 – Dec 2015 @ 5%) 77.0 81.1

TOTAL ESCALATED PROJECT COST 351.0 369.2


As detailed in the above table, an escalation of 5% per year has been assumed for the life of the project. This level of escalation is considered appropriate for a specialised tunnelling/marine spread project such as this.

Once the base estimate is prepared, the risk elements are addressed. Several risk analysis workshops were held to obtain the input of a range of experienced people. For each row item in the base estimate (not shown in Table 7.1), variations in both the quantities and rates were estimated and adopted. The contingent risks were also identified and probabilities and values were adopted at the risk workshop. The @RISK software package was then used to perform the quantitative analysis on the inherent and contingent risk, in order to obtain an objective view of the risk in the project. The probabilities of achieving various project cost outcomes (P5, P50 and P95) were then determined. This is described in more detail below.

7.3 Inherent Risks Key items considered in the inherent risks were :

potential for mobilisation costs to be higher depending on availability of critical equipment

additional works required once geotechnical conditions are determined

opportunity to source tunnel segments at a lower cost

opportunity to grout instead of ground freezing for cross passage construction

opportunity to reduce cross passage length

opportunity to grout for pick replacement from inside tunnel rather than using marine spread

potential for increased riser length once geotechnical conditions are determined

7.4 Contingent Risks Key items considered in the contingent risks were :

Delay in project commencement due to funding/approval issues increases escalation

Additional power network upgrade costs incurred

Major mechanical failure of the TBM during construction

Delays in delivery of overseas plant

Scope creep

Additional cost of mobilising a jack-up barge from overseas rather than using a local jack-up should marine conditions necessitate


7.5 Summary of Cost Estimate Once the base estimate was finalised, the @RISK program was run. The results are presented in Table 7.2

Table 7.2 Risk Adjusted Cost Estimates for Option 1 and Option 2

Option 1 ($M) Option 2 ($M) Description

Base P95 P50 P5 Base P95 P50 P5

Total Project Cost including risk 274 324 305 285 288 338 317 298

Total Escalated Project Cost including risk 351 403 382 362 369 422 399 378


8. Operation and Maintenance Considerations

The following operation and maintenance activities and costs have been identified. Additional experience from Sydney Water and Black & Veatch has been used to generate this information.

Shaft and purging pump station activities. These assets consist of the shaft and purging structure including the pump station. Incorporated into these facilities will be a water level and flow monitoring system and the pump station will most likely be linked to ETP by SCADA. These assets will require civil, mechanical and electrical maintenance activities in addition to energy and consumables requirements for the pumping station. Odour control costs have not been estimated at this stage, but routine replacement of activated carbon and disposal costs could be substantial. Provisional cost estimates are as follows:

– Civil maintenance at 0.5% of works (shaft and purging structure) - $50,000 per year

– Mechanical and electrical maintenance including support contract for monitoring system - $100,000 per year

– Operation of purging pumps - $10,000 per year

Inspection of the diffusers. This will be undertaken using divers or a remotely operated vehicle (ROV). As the diffuser condition is critical to the operation of the outfall, this inspection will be carried out annually. Cost estimate is:

– Mobilisation, inspection (two weeks), demobilisation and reporting - $70,000 per inspection

Cleaning of the diffusers. Periodic cleaning around the diffuser ports may be necessary to remove marine growth depending on the extent to which it builds up. This could be undertaken by divers or ROV. It has been assumed this will be required every five years. Cost estimate is:

– Mobilisation, cleaning (three weeks), demobilisation and reporting - $200,000 per clean

Inspection of inlet shaft and outfall tunnel. The inlet shaft and outfall tunnel are assumed to generally be maintenance free. The tunnel will be inspected by ROV every three years to check the condition. Cost estimate for ROV inspection is :

– Set-up of specialist ROV team, inspection (one week) and reporting - $100,000 per inspection


Appendix A

Preliminary Environmental, Planning and Cultural Heritage Investigations

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Appendix A

Contents

A. Preliminary Environmental, Planning and Cultural Heritage Investigations 1

A.1 General Comments 1 A.2 Options 1 A.3 Terrestrial Environmental Issues 1 A.4 Relevant Environmental Approvals 9 A.5 Planning Approvals 12 A.6 Cultural Heritage Approvals 20 A.7 Works Approval and Licence to Discharge 24 A.8 Environmental Effects Act 1978 24 A.9 Conclusions Regarding Environmental Impacts and Permitting. 24 A.10 Estimated Cost of the Environmental, Planning and Cultural

Heritage Investigations 26

Table Index Table A-1 Ecological Vegetation Classes (EVCs) near the

proposed works. 5 Table A-2 Environmental Approval Requirements that may be

relevant to the proposed project. 9 Table A-3 Summaries of Relevant Policies and Strategies 11 Table A-4 Planning zones and overlays and planning permit

requirements. 16 Table A-5 Summary of legislation, which may result in the need for

approvals 25 Table A-6 Estimated Cost of the Environmental, Planning and

Cultural Heritage Approvals for both Options 1 and 2. 27

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Figure Index Figure A-1 Spray Zone Coastal Scrubland to the east of the

access road. 2 Figure A-2 The areas around the access road to the car park

showing the extensive shell middens that have previously been exposed. 2

Figure A-3 Coastal headland Scrub EVC in near the existing structures behind the dunes. 3

Figure A-4 Coastal Alkaline Scrub EVC alongside the existing access track to the site. 3

Figure A-5 Area surrounding the existing drop structure. 7 Figure A-6 Alkaline Coastal Scrub EVC in between the golf

course and the existing drop structure. 7 Figure A-7 Planning Zones 14 Figure A-8 Planning Overlays 15 Figure A-9 Cultural Heritage Sensitivity Map 21 Figure A-10 Protected Matters Search Results for Heritage 23

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A. Preliminary Environmental, Planning and Cultural Heritage Investigations

This section of the report outlines potential environmental impacts and the statutory approvals that may be required for the proposed works at the South Eastern Outfall Extension, which comprises a tunnel, risers, diffusers and pump station at Boags Rocks, Mornington Peninsula. The potential works assessed in section include the geotechnical investigations as described in Appendix B.

This section considers the following streams of approvals that may be required, including:

Environmental Approvals;

Planning Approvals; and

Heritage Approvals.

A.1 General Comments The southern coastal area of the Mornington Peninsula is environmentally sensitive and contains many areas of high conservation significance. There are a number of levels of protection relating to this area. The coastal fringe and some of the hinterland comprises part of the Mornington Peninsula National Park. There are also a number of planning controls that protect specific areas of environmental, archaeological and landscape significance in the area. Other natural and cultural assets in the area are protected via a range of legislation and policy.

The environmental impacts of the powerline to the site, which will be required, have not been considered at this stage. These impacts will need to be considered at the next stage.

A.2 Options There are two options assessed for this report. These are:

Option 1 Works, including the HCD for the geotechnical investigations located at the site of the existing drop structure immediately behind the dune area in the National Park.

Option 2 Works including the HCD for the geotechnical investigations located in the golf course with no surface works within the National Park.

A.3 Terrestrial Environmental Issues

The cliffs and dune system The cliffs and dunes are of high conservation significance and also of very high archaeological significance. The ecological vegetation community (EVC) that inhabit the cliff tops and the exposed dune areas is Spray Zone Coastal Scrubland (Figure A-1), a vegetation community that is considered rare.

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Figure A-1 Spray Zone Coastal Scrubland to the east of the access road.

The dunes contain aboriginal middens comprising extensive and stratified shell deposits (Figure A-2). Permission to disturb these highly sensitive areas would likely be extremely difficult if not impossible to obtain. Neither of the options have any construction proposed in the dune or foreshore areas.

Figure A-2 The areas around the access road to the car park showing the extensive shell middens that have previously been exposed.

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Figure A-3 Coastal headland Scrub EVC in near the existing structures behind the dunes.

Figure A-4 Coastal Alkaline Scrub EVC alongside the existing access track to the site.

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Between the dunes and the golf course Archaeological Issues

The large middens that are so conspicuous along the dunes extend some distance inland, the exact extent of which is unknown in the absence of a detailed survey. A detailed archaeological field survey would be required to establish the extent of the middens and indeed other archaeological sites that may be present in the area. Section A.6 outlines the requirements for a Cultural Heritage Management Plan and discusses the sensitivity in the area further.

Vegetation Removal

The construction of the tunnel is likely to require a construction area situated to the north of the immediate coastal strip. There are potential sites at either the location of the drop structure, immediately behind the dunal system, or in the golf course some 820 metres to the north. Both of these sites would require some clearance of vegetation. Any clearance of native vegetation would require a permit under Victoria’s Native Vegetation Management Framework (generally known as Net Gain), which is administered by DSE through the Planning and Environment Act 1987. This is discussed in more detail in Section A.5 – Planning Approvals.

Net Gain requires that any vegetation removal be offset by replacement with vegetation of greater quality and/or quantity. The unit of measurement for Net Gain is the habitat hectare, which in broad terms is the product of the quantity and quality of vegetation. Offsets can be gained through improving the habitat hectare score of vegetation such that the offset is of greater value in terms of habitat hectares than the vegetation that is proposed to be removed. Offsets can be gained by replanting (not generally acceptable), by management actions such as weed and pest removal and/or by reserving the vegetation community. Vegetation communities of high or very high conservation significance need to be offset by management actions rather than revegetation and suitable offsets would therefore need to be found.

The requirement for Net Gain is that the following steps are considered when assessing the development of projects:

1. To avoid adverse impacts, particularly through vegetation clearance;

2. If impacts cannot be avoided, to minimise impacts through appropriate consideration in planning processes and expert input to project design or management; and

3. Identify appropriate offset options.

There are three Ecological Vegetation Classes that are recognised for the local area of the proposed works including any investigative and geotechnical investigations that may be required, these are shown in Table A-1.

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Table A-1 Ecological Vegetation Classes (EVCs) near the proposed works.

EVC Bioregional Status Comment

Spray Zone Coastal Scrubland (Figure A-1)

Rare Clearing generally not permitted. Unlikely that this EVC on the cliff tops would be cleared as part of the current project.

Coastal Headland Scrub

(Figure A-3)

Depleted Clearing generally not permitted. This EVC is in the dune area and is not likely to be impacted by the proposed project.

Coastal Alkaline Scrub (Figure A-4, Figure A-6)

Vulnerable Clearing generally not permitted. This EVC is the ti-tree scrub that ends at the golf course. Much better if the works do not involve clearing this vegetation as project delays and additional expense may be caused through the need for Net Gain offsets which may be difficult to obtain.

If there were to be any disturbance of the Coastal Alkaline Scrub EVC then significant Net Gain liabilities may arise.

A.3.1 Net Gain Liabilities

As indicated above clearing of native vegetation would likely require offsets under Victoria’s Native Vegetation Management Framework (Net Gain) administered through the Mornington Shire Planning Scheme. The vegetation clearance and offset strategy that has been assumed for the project is consistent with MWC and DSE requirements for native vegetation management.

The three steps to undertake the process of management of clearance of native vegetation is as follows:

1. Avoidance. The EVCs in the dune area, Coastal Headland Scrub and Spray zone Coastal Scrubland are unlikely to be impacted by the proposed works and as such avoidance of these EVCs is possible. Avoidance of any clearance of the Coastal Alkaline Scrub EVC is likely to be much more difficult for Option 1 than Option 2, the latter likely requiring little or no clearance of this EVC. For Option 1 the existing access track to the outfall site will likely need to be widened and this will require clearance of some Coastal Alkaline Scrub. Other clearance may also be required for Option 1 for other activities such as establishing power to the site.

2. Minimise clearance. It is assumed that every effort would be made to minimise any clearance that may be necessary. Again some clearance of the Coastal Alkaline Scrub appears unavoidable for Option 1 and potentially avoidable for Option 2.

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3. Offset. As clearance appears unavoidable it is assumed that there will be some offsets required. The extent of these offsets remains unclear though some broad estimates can be made.

The conservation significance of any EVC that may be cleared has a considerable influence on the amount and nature of any offsets required. Conservation significance is determined by a range of factors including the bioregional status of the EVC, condition, weediness, patch size, structure, land tenure and overall relationship to conservation values in the area. A detailed field investigation is required before the exact conservation significance of the EVC is known and the impact on the offsets can be large, potentially up to four or five times the habitat hectares.

The Alkaline Coastal Scrub will likely be either rated as high or very high conservation significance. Such a rating puts constraints on the actions that can be taken to achieve offsets. For example the amount of revegetation required to achieve an offset is limited to 10% for very high conservation significance vegetation and 25% for high conservation significance vegetation. The amount of offset required is also high with very high conservation significance vegetation requiring at least twice the number of habitat hectares lost to be offset and high conservation significance vegetation requires at least 150% of the amount of loss to be offset.

It is clear therefore that the conservation significance of the vegetation to be offset is important in the determination of the actual amount of offsets required, whether this is by revegetation or other means of offsetting. As the conservation significance cannot be determined until a full field investigation of the vegetation to be cleared is undertaken, the amount of offsets required will remain unknown even if the exact area of vegetation to be cleared is known.

Some revegetation can be applied to the gaining of offsets for the Coastal Alkaline Scrub but the majority of the offsets need to be obtained through reservation or better management of existing vegetation on the Mornington Peninsula. Revegetation may be possible onsite but most of the offsets are likely to be required to be obtained offsite. This means finding vegetation that can either have its habitat hectare score improved or purchasing Alkaline Coastal Scrub from private landholders. In either case at least ten years of care and maintenance of the vegetation would be required.

Negotiations with landholders, DSE and other parties will be required to identify and obtain these offsets. These costs have been considered in the budgetary estimate presented in Table A-6.

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Figure A-5 Area surrounding the existing drop structure.

Figure A-6 Alkaline Coastal Scrub EVC in between the golf course and the existing drop structure.

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A.3.2 Marine Environment

Extensive surveys of the marine environment have been undertaken for the previous Works Approval Application (WAA) and monitoring. There is the potential for localised but high level disturbance to subtidal marine habitats, the only real impacts on the intertidal environment will be those that result from the cessation of flows from the existing outfall. With the cessation of discharges into the intertidal area the benthic communities in area surrounding the existing outfall should revert to a composition and structure similar to those that inhabit neighbouring reefs. The process of re-establishing the community may take around five years with some external assistance potentially being required to establish macroalgae such as Hormosira and Durvillaea due to the low dispersal capabilities of these algae. The approvals that will be likely to be required are those associated with the EPA works approval.

Fish There are commercial fisheries in Bass Strait for species such as Whiting, Flathead, Ling and Gummy Shark. The commercial rock lobster fishery operates in areas around Cape Schanck and Abalone is also taken from around inshore reefs. A number of these fishes are listed as rare or threatened such as the Great White Shark. There is potential for construction works to impact upon the ecology of a range of these fishes although this would be expected to be a limited impact that is relatively short-lived (ie for the duration of the construction period only).

Marine Mammals The Action Plan for Australian Cetaceans lists 23 species whose distribution includes southern Australia. Many of these are likely to be found in Bass Strait. Of particular importance are the migrating Southern Right Whales, and Blue Whales, which have been raised in other areas subject to construction in the Bass Strait. At the Nobbies on Phillip Island to the east of the construction area, the largest colony of Australian Fur Seals exists. These animals are likely to forage for fish in the area of the proposed outfall construction. Noise from construction activities such as blasting and the use of sonar are the main concerns in terms of impacts on marine mammals. In particular the use of seismic surveys for geotechnical investigations would be required to be undertaken using EPBC Act Policy No 2, which sets guidelines for the conduct of seismic investigations when cetaceans are potentially present.

Seabirds The impact of construction on seabirds is likely to be localised and may not impact many birds apart from the Little Penguin. This bird feeds on pelagic fishes, particularly pilchards, in Bass Strait. Construction activities may disturb the feeding of the penguin in a localised area and this disturbance may persist for the duration of the construction.

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A.4 Relevant Environmental Approvals A number of statutory environmental approvals may be required for this project, these are summarised in Table A-2 below.

Table A-2 Environmental Approval Requirements that may be relevant to the proposed project.

Legislation Description Approval Requirements

Environment Protection and Biodiversity Conservation Act 1999

The Environment Protection and Biodiversity Conservation Act, 1999 (EPBC Act) provides that certain actions – in particular, actions that are likely to have a significant impact on a matter of national environmental significance – are subject to a rigorous assessment and approval process. Unless an exemption applies, the matters of National Environmental Significance identified in the Act as triggers for the Commonwealth assessment and approval regime are: World Heritage Properties; Ramsar Wetlands; Nationally threatened species and ecological communities; Migratory species; Commonwealth marine areas; Nuclear actions (including uranium mining) and National Heritage places.

There are unlikely to be major EPBC Act issues concerning terrestrial ecology for either option, though a referral under the Act is likely to be required. There are unlikely to be any impacts on Commonwealth marine areas therefore any investigations are likely to be confined to Victorian waters.

Targeted survey and assessment is, however, likely to be required for the EPBC-listed Leafy Greenhood Pterostylis cucullata (would need to be undertaken in September/October as this is the time when the orchids are flowering and identification, which is based on the flower, is possible).

Additional survey would be needed to provide information for a referral to the Commonwealth under the EPBC Act.

Victorian Planning and Environmental Act 1987

The Planning and Environmental Act, 1987 (P&E Act) ensures integrated land use planning decision-making. Planning authorities and responsible authorities must adhere to the general principles and the specific policies contained in the P&E Act. The Victorian Planning Provisions are the standard planning provisions that every municipality must adhere to in their Planning Schemes.

Victoria’s Native Vegetation Management Framework (Net Gain) is administered through the Planning and Environment Act. DSE is a referral authority under this provision. Detailed discussion of potential impacts of Net Gain on the project are discussed in Section A.3.1

The relevance of this Act has been discussed in Section A.5, including planning permit triggers under the Mornington Planning Scheme.

Victorian Flora and Fauna Guarantee Act 1988

The Flora and Fauna Guarantee Act, 1988 is the primary overarching statute dealing with biodiversity conservation and sustainable use of native flora and fauna in Victoria. State government, public authorities, statutory authorities as well as private landholders must have regard to the objectives of the FFG Act.

A flora and fauna assessment is required to determine whether any approvals may be required under this Act.

Victorian Environment Effects Act 1978

The Environment Effects Act 1978 provides for the assessment of proposed public and private projects (works) that are capable of having a significant effect on the environment. The Act does this by enabling the Minister administering the Environment Effects Act to decide that an Environment Effects Statement (EES) should be prepared.

In order to conclusively determine whether the project has any significant adverse effects on the environment, an assessment of environmental effects needs to be undertaken using the ‘Ministerial Guidelines for Assessment of Environmental Effects under the Environmental Effects Act 1979’.

There are specific triggers identified in the Act and a referral would need to be undertaken so that the Minister could determine the requirement or otherwise for

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Legislation Description Approval Requirements an EES.

Based on discussions with MWC an appropriately conservative position has been taken that an EES may be required for the project and as such consideration has been given to the conduct of an EES in the costs prepared.

Catchment and Land Protection Act 1994 (CALP Act)

Under Section 20 of the Act, a landowner has a general duty to take all reasonable steps to manage the landscape of the construction site.

Melbourne Water, as the landowner must observe its general duties under Section 20 of the Act.

Water Act 1989 This Act has the following purposes to provide for the integrated management of all elements of the terrestrial phase of the water cycle and to provide a framework for the environmental management and enhancement of waterways.

No approvals are considered to be likely under this Act.

National Parks Act 1975

This Act makes provision for National and other parks and for their management, the appointment of a Director of National Parks and the appointment of a National Parks Advisory Council and park advisory committees. This Act also provides for specialised uses and activities, including those of a non-conforming nature.

Any works undertaken in the Mornington Peninsula National Park which comprises land to approximately 300 metres from the shoreline would trigger a permit from Parks Victoria under the National Parks Act. Option 1 requires works in the National Park and as such the environmental impacts and management would need to be demonstrated to Parks Victoria.

Crown Land (Reserves Act) 1978

This Act provides for reservation of Crown land for a variety of public purposes, the appointment of committees of management to manage those reserves and for leasing and licensing of reserves for purposes approved by the Minister.

Confirmation from DSE is required as to whether the proposal will require a licence under Section 17B of the Act to use any reserved portions of Crown land, where the purpose differs from the purpose for which the land is reserved.

Land Act 1958 This Act makes provision for sale and occupation of unreserved Crown lands, and authorises the issue of various types of leases and licences.

Confirmation from DSE is required as to whether the proposal will require any approvals under the Act to use any unreserved portions of Crown land. Some of the seabed of Bass Strait is unreserved Crown Land.

Environment Protection Act 1970

This Act provides the legislative framework for environment protection in Victoria, including the principles of environment protection. State Environment Protection Policies and Waste Management Policies are made under this Act.

The proposed works may require an additional works approval from the EPA. Clarification will need to be sought from the EPA to establish whether this is the case or not.

Clarification will also be needed as to whether the extended outfall is considered a new discharge or not as there are different requirements for new and existing discharges under the SEPP (WoV).

In any case substantial work will be required to determine the potential environmental impacts of the discharge of wastes at a new location.

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Legislation Description Approval Requirements

Coastal Management Act 1995

The purposes of this Act are

To establish the Victorian Coastal Council;

To provide for the establishment of Regional Coastal Boards;

To provide for co-ordinated strategic planning and management for the Victorian coast

To provide for the preparation and implementation of management plans for coastal Crown land; and

To provide a co-ordinated approach to approvals for the use and development of coastal Crown land.

The Coastal Management Act 1995 defines coastal Crown land as:

Any land reserved under the Crown Land (Reserves) Act 1978 for the protection of the coastline;

Any Crown land within 200 metres of the high water mark of the coastal waters of Victoria; or any sea within the limits of Victoria;

The sea-bed of the coastal waters of Victoria; and

The sea-bed of any sea within the limits of Victoria.

Under the Act, consent is required to use and develop coastal Crown land. This includes day-to-day maintenance activities. The definition of development under the Act includes the ‘construction or carrying out of works’. ‘Works’ include any change to the natural or existing condition or topography of land including the removal, destruction or lopping of trees and the removal of vegetation or topsoil. The project will hence require written consent under the Act from the Department of Sustainability and Environment (DSE). If the project proposes to dredge coastal Crown land, a specific application form must be completed. Copies of this form can be found in the EPA Best Practice Management Guidelines for Dredging or by contacting DSE. If consent is not given, a planning permit application must be refused. There is no right to apply to the Victorian Civil and Administrative Tribunal for a review of a decision by the responsible authority to refuse to grant a permit where Coastal Management Act consent has been denied.

Pollution of Waters by Oil and Noxious Substances Act 1986 (27/1986)

This Act seeks to protect the sea and certain waters from pollution by oil and other noxious substances and to implement the MARPOL Convention.

There are unlikely to be an implication of this Act on either of the proposed options.

A.4.1 Relevant Policies, Strategies and Guidelines

In assessing the potential impacts and benefits of the project, a range of national and state level policies and strategies must be considered. A summary of the relevant documents is provided in Table A-3 below.

Table A-3 Summaries of Relevant Policies and Strategies

Policy /Strategy Description Relevance to Project

State Environment Protection Policy (Waters of Victoria)

SEPP (Waters of Victoria) and its Schedules provide for the protection of Victoria’s surface water environment and associated beneficial uses.

The project will be required to meet the water quality objectives described within the SEPP(WoV). That the project is likely to meet these requirements will need to be demonstrated to the EPA in order to obtain a licence to discharge. Demonstration of the ability to meet the guidelines will likely require detailed hydrodynamic modelling, ecological assessment and ecotoxicological investigations.

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Policy /Strategy Description Relevance to Project A construction and operational EMP specific to the project will need to be be prepared to manage any potential risks to surface waters.

State Environment Protection Policy (Groundwaters of Victoria)

SEPP (Groundwaters of Victoria) was developed to protect and, where necessary, improve groundwater quality to protect the beneficial uses of groundwaters. The SEPP outlines beneficial uses according to concentration of Total Dissolved Solids (TDS) and groundwater quality indicators and objectives for each beneficial use.

Investigations will be needed to demonstrate that the project will not compromise the objectives of the SEPP (GoV).

A construction EMP specific to the project should be prepared to manage any potential risks to groundwater.

State Environment Protection Policy (Air Quality Management)

The SEPP (Air Quality Management) provides a framework for the management and monitoring of emissions to air. This SEPP aims to enable the achievement of the environmental air quality objectives as outlined in the SEPP (Ambient Air Quality).

Investigations will be needed to demonstrate that the project will not compromise the objectives of the SEPP (AQM).

A construction EMP specific to the project should be prepared to manage any dust emissions arising from the works.

State Environment Protection Policy (Control of Noise from Commerce, Industry and Trade) N1

SEPP (Control of Noise from Commerce, Industry and Trade) provides for the protection of sensitive residential areas from noise emissions arising from Commerce, Industry and Trade. The SEPP also outlines the methods to be used for calculating noise limits and measuring noise emissions.

A construction EMP specific to the project should also be prepared to manage any issues of site contamination.

EM 021-2005: Coastal Engineering Guidelines for Working with the Australian Coast in an Ecologically Sustainable Way

The issues covered within the Guidelines include government policy, professional ethics, the nature of the coastal environment and development within it, coastal engineering methodology including recommended investigation procedures and project planning for economic sustainability.

The Guidelines are not designed to dictate the detailed procedures to be followed, but rather identify the types of processes and relevant considerations.

Victorian Native Vegetation Management Framework 2002

Victoria’s Native Vegetation Management – A Framework for Action and the regional Native Vegetation Plans are incorporated documents under the provisions of the Planning and Environment Act 1987.

The Framework requires the three step approach to ensure Net Gain:

Avoid adverse impacts, particularly through avoiding vegetation clearance.

If impacts cannot be avoided, minimise impacts through appropriate consideration in planning processes.

Identify appropriate offset options.

Since it is likely that vegetation removal will be required during construction of the pipeline, the project will need to comply with the requirements of this Framework.

A.5 Planning Approvals Planning approval is likely to be required for the proposal, including the removal of native vegetation, pursuant to the Planning and Environment Act 1987(P&E Act). The proposed works are subject to the Mornington Peninsula Planning Scheme.

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A.5.1 Planning and Environment Act 1987 (P & E Act)

The P&E Act establishes the framework for integrating policies and environmental considerations into planning decisions affecting land across Victoria. In doing so, the P & E Act:

Establishes a system of planning schemes with local and state sections into which appropriate controls for the use, development and protection of land can be incorporated;

Establishes duties, powers and responsibilities for key authorities in the system; and

Sets out the process by which an applicant must follow to ensure accordance with the P & E Act and associated mechanisms.

A.5.2 Victorian Planning Provisions

Pursuant to Clause 74 of the Mornington Peninsula Planning Scheme, the proposed works, may be defined as a ’ Utility Installation’.

A utility installation is defined as:

Land Used:

C) To collect, treat, or dispose of storm or flood water, sewerage, or sullage.

The planning permit requirements for the defined use and buildings and works are triggered by the zones and overlays and related provisions of the Mornington Peninsula Planning Scheme.

The zones and overlays that may apply to the area of works on the land are shown in Figure A-7 and Figure A-8. The purpose of the zones and overlays and the planning permit requirements for each option are discussed in Table A-4 below.

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Figure A-7 Planning Zones

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Figure A-8 Planning Overlays

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Table A-4 Planning zones and overlays and planning permit requirements.

Zone/Overlay/ Clause

Purpose Comment Planning permit requirements

Green Wedge Zone 4

Clause 35.04

To recognise, protect and conserve green wedge land for its agricultural, environmental, historic, landscape, recreational and tourism opportunities, and mineral and stone resources. To encourage use and development that is consistent with sustainable land management practices. To encourage sustainable farming activities and provide opportunity for a variety of productive agricultural uses. To protect, conserve and enhance the cultural heritage significance and the character of open rural and scenic non-urban landscapes. To protect and enhance the biodiversity of the area.

This zone applies to the landward side of the National Park including the golf course.

Applies to Option 2

Pursuant to Clause 35.04-1 a planning permit is required for the use. Pursuant to Clause 34.04-5, a planning permit is required for buildings and works.

Public Use Zone 1

Service and Utility

Clause 36.01

To recognise public land use for public utility and community services and facilities. To provide for associated uses that are consistent with the intent of the public land reservation or purpose.

The existing pipeline is located within the PUZ1.

Applies to Option 2

Pursuant to Clause 36.01-6 a planning permit is not required for the use as the use is for a ‘service and utility’.

Road Zone 2 (RDZ2)

Clause 36.04

To identify significant existing roads. To identify land which has been acquired for a significant proposed road.

The road is in close proximity to the works.

May apply to Option 2

Pursuant to Clause 36.04-1, a planning permit is required for the use. Pursuant to Clause 36.04-2, a planning permit is required for buildings and works.

Public Conservation and Resource Zone (PCRZ)

Clause 36.03

To protect and conserve the natural environment and natural processes for their historic, scientific, landscape, habitat or cultural values. To provide facilities which assist in public education and interpretation of the natural environment with minimal degradation of the natural environment or natural processes. To provide for appropriate resource based uses.

The zone applies to the area contained within the Mornington Peninsula National Park.

Applies to Option 1

Pursuant to Clause 36.03-1, a planning permit is not required for the use if the following applies:

A use conducted by or on behalf of a public land manager or Parks Victoria under the relevant provisions of various Acts including the Water Industry Act 1994, the Water Act 1989, and the Marine Act 1988.

If none of the above applies, then a planning permit would be required.

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Environmental Significance Overlay 15

The Cups

Clause 42.01

To identify areas where the development of land may be affected by environmental constraints. To ensure that development is compatible with identified environmental values.

Schedule 15 to ESO - This area is formed from semi-consolidated sand dunes and extends to the coastline of Bass Strait, adjoining the Point Nepean National Park. It is a major catchment area for the ground water resources of the Nepean Peninsula. It is also an area of strategic landscape importance, providing a distinctive landscape experience and forming the rural edge to the townships of Rye and St Andrews.

This overlay covers all of the areas that may be considered for works in this project.

Applies to Option 2

Pursuant to schedule 15 of Clause 4.01 a planning permit is not required to remove, destroy or lop vegetation that is not native vegetation.

Other exemptions are listed however evidence will need to present to demonstrate that the values of the area are protected.


Active Dunes

Clause 42.01


Schedule 22 to ESO -The stability of coastal areas is critical to coastal management and the maintenance of environmental values. Active dune areas are exposed to primarily to wind erosion and may be destabilised by buildings and works, including the removal of vegetation.

This overlay covers all of the areas that may be considered for works in this project.

Applies to Option 1

Pursuant to Clause 42.01-2 a planning permit is required to remove vegetation.

Any exemptions listed in Clause 52.17 do not apply on an ESO.


Semi Stabilized Dunes Clause 42.01


Schedule 22 to ESO - The stability of semi-stabilised dunes is critical to sustainable land management and the maintenance of environmental values. These areas may become unstable if the top surface is removed in steeper sections and exposed to wind erosion

Applies to Option 2 Pursuant to Clause 42.01-2 a planning permit is required to remove vegetation.

Any exemptions listed in Clause 52.17 do not apply on an ESO.


Site Of Scientific Significance Clause 42.01


Schedule 22 to ESO states that there are a number of sites of scientific significance have been identified. These include:

Sites of archaeological significance relating to the pre European history of the Peninsula.

Sites of botanical significance.

Sites of geological significance- these sites are of cultural, scientific and educational value to current and future generations.

This overlay is located around the outfall itself and extends approximately 250 metres inland.

Applies to Option 1

Pursuant to Clause 42.01-2 a planning permit is required to remove vegetation.

Schedule 24 of Clause 42.01 states that: an application must include a report from a suitably qualified person or persons, demonstrating that the archaeological, botanical, geological and zoological values of the site have been addressed.

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Significance Landscape Overlay 2

Coastal Landscape

Clause 42.03

To identify significant landscapes. To conserve and enhance the character of significant landscapes. Schedule 2 to SLO states that Coastlines and coastal hinterland areas have been identified as key landscape features. These areas have an open rural character, and are often cleared, with a history of broad scale grazing. They act as a landscape foreground to coastlines and seascapes, with transitional areas ranging from extensive dune and beach areas to abrupt high basalt and limestone cliffs. The open landscape character makes these areas susceptible to visual intrusion from inappropriate development and the use of landscaping to screen buildings and works must be balanced with maintaining extensive viewlines.

Construction activities will present a visual impact to the surrounding areas.

Applies to Option 1

Pursuant to schedule 2 of 42.03, a planning permit is required to remove vegetation within this overlay.

Significance Landscape Overlay 3

Scenic Roads

Clause 42.03

To identify significant landscapes. To conserve and enhance the character of significant landscapes.

Schedule 3 to the SLO states Scenic roads have been identified as key landscape features. Scenic drives on the Mornington Peninsula are major recreational resource and development adjacent to scenic roads may substantially effect the perception of landscape quality and the associated recreational value.

Construction activities will present a visual impact to the surrounding areas.

Applies to Option 2

Pursuant to schedule 4 of 42.03, a planning permit is required to remove vegetation within this overlay.

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A.5.3 Vegetation Removal

It is likely that vegetation removal will be required during the geotechnical investigations as well as the construction of the shaft, diversion structure and purging structure, therefore the provisions of Clause 52.17 - Native Vegetation, of the Mornington Peninsula Planning Scheme apply. Discussion of the potential impacts of vegetation clearance is in Section A.3.

Removal of native vegetation would need to follow the principles of Victoria’s Native Vegetation Management Framework, which Melbourne Water follows in its guidelines for dealing with Net Gain issues. These principles require a three-step process of decisions when dealing with potential removal of native vegetation.

Avoid adverse impacts, particularly through avoiding vegetation clearance;

If impacts cannot be avoided, minimise impacts by careful planning, design and management; and

If clearing must occur, the clearing must be offset.

The framework and Melbourne Water’s guidelines require that offsets be found within the impacted site if possible and only if no offsets are available onsite should offsite offsets be considered.

It is required that the process of considered avoidance, minimisation and the consideration of offsets be adequately demonstrated.

A.5.4 Summary of Planning Permit Requirements

The proposed works may be defined as a ‘Utility Installation’. A planning permit for the use, buildings and works and vegetation removal will be required for the project, triggered by the following Zones and Overlay:

Green Wedge Zone;

Road Zone;

Environmental Significance Overlay; and

Significant Landscape Overlay.

A Planning Permit may also be required to remove native vegetation pursuant to the requirements of Clause 52.17 of the Mornington Shire Planning Scheme.

Our interpretation of the definition of the proposed works and the planning permit requirements should be confirmed in writing by the Shire of Mornington Peninsula.

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A.6 Cultural Heritage Approvals This section provides a preliminary qualitative assessment of both post-contact built heritage and Aboriginal cultural heritage for the proposed study area. A review of existing public databases was conducted as part of this preliminary assessment.

A.6.1 Aboriginal Heritage Act 2006

The Aboriginal Heritage Act 2006 commenced on 28 May 2007, replacing the previous Aboriginal cultural heritage regime in Victoria, governed by the Aboriginal and Torres Strait Islander Heritage Protection Act 1984 (Comm.) and the Archaeological and Aboriginal Relics Preservation Act 1972 (Vic.).

Key features of the Aboriginal Heritage Act 2006 include:

The creation of the Aboriginal Heritage Council, with membership of traditional owners who will advise on the protection of Aboriginal heritage;

The use of Cultural Heritage Management Plans (CHMPS) for certain development plans or activities;

The ability for registered Aboriginal parties (‘RAPs’) to evaluate management plans, advise on permit applications, enter into cultural heritage agreements and negotiate the repatriation of Aboriginal human remains; and

Alternative dispute resolution procedures.

A Cultural Heritage Permit may be required to disturb an aboriginal site or relic, particularly if no Management Plan is in Place. A CHMP is required for high impact activities in areas of cultural heritage sensitivity as discussed below.

A.6.2 Aboriginal Cultural heritage Mapping

The Victorian Aboriginal Heritage Register is maintained by Aboriginal Affairs Victoria (AAV) and contains details of all known Aboriginal Cultural Heritage features in Victoria. This Register is not publicly accessible due to the sensitivity of information contained within it. Aboriginal Affairs Victoria has also produced maps indicating areas of cultural heritage sensitivity as defined under the Aboriginal Heritage Regulations 2007. This mapping can be viewed on the AAV website and in more detail on the Department of Primary Industries website -within the Minerals and Petroleum Division's website.

A review of the mapping indicates that shell middens have been found within or in close proximity of the site. These sites are protected and there are significant fines for causing harm to protected heritage places. The existing pipeline is located within an area that has been identified as being culturally sensitive (coastal Crown land and all areas within 200 metres of the high water mark of the coastal waters of Victoria or any sea within the limits of Victoria is an area of cultural heritage sensitivity). The cultural Heritage Sensitivity Map is shown in Figure A-9 below.

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Figure A-9 Cultural Heritage Sensitivity Map

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Pursuant to Section 43 division 5 of the Aboriginal Cultural Heritage Regulation 2007 a ‘utility installation’ is defined as a ‘High Impact Activity’ (i.e. projects which cause significant ground disturbance). Projects which are considered to be ‘high impact activities’ within areas of Cultural heritage sensitivity will require the preparation of a Cultural Heritage Management Plan (CHMP) in accordance with the Aboriginal Cultural Heritage Act 2006 and the Aboriginal Heritage Regulations 2007.

The areas surrounding the proposed works, including the geotechnical investigations, are also located within Cultural heritage sensitivity as identified on the Aboriginal Affairs Victoria (AAV) mapping.

It is noted that there is no accepted Registered Aboriginal Party for the area within which the proposed works will be located.

A.6.3 Native Title

‘Native title’ is defined under Section 223 of the Native Title Act, 1993, to mean the communal group or individual rights and interests of Aboriginal people or Torres Strait Islanders in relation to land or waters where those rights and interests are those possessed under traditional laws and customs, those laws and customs give a connection with the land or waters and the rights and interests are recognised by common law.

In summary, native title will exist in an area where, in accordance with their laws and customs, indigenous people have maintained their connection with the area and their title has not been extinguished. Extinguishing acts include the grant of freehold and the grant of a lease that grants exclusive possession. The decision of the High Court in Wik indicates that not all leases will necessarily be seen as granting exclusive possession.

A search of the Applications and Determinations of Native Title in Victoria must be carried out to establish whether native title has been extinguished.

A.6.4 Post-Contact Built Heritage

The following databases were searched to identify post-contact built heritage items:

National Heritage places, Commonwealth Heritage places and places on the Register of the National Estate (RNE) searched using the EPBC Act Protected Matters Search Tool;

The Victorian Heritage Register; and

Heritage Overlays for the Mornington Shire Planning Scheme.

The search results are shown below in Figure A-10. The search indicated that no World Heritage Places, Commonwealth Heritage Places or National Heritage Places have been recorded within the study area. However the site and surrounding area is on the Register of the National Estate. This area applies to the ‘Cup County’ the ‘Cape Schanck Coastal Park and the Cape Schanck Landscape area’. The coast is also identified as a ‘protected area’, which applies to the Mornington Peninsula National Park. No heritage overlays are within are area.

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Figure A-10 Protected Matters Search Results for Heritage

A.6.5 Summary of Cultural Heritage Issues

The proposed works including the geotechnical investigations, defined as a high impact activities, are located within an area of Culturally heritage sensitivity, which is likely to contain shell middens, therefore a mandatory Cultural Heritage Management Plan will be required for the project. At present there is no

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Registered Aboriginal Party (RAP) for the locality, therefore a CHMP would be determined by Aboriginal Affairs Victoria (AAV).

An assessment by a suitably qualified heritage consultant should be carried out, to determine the potential impact of the proposal on cultural heritage.

A.7 Works Approval and Licence to Discharge In order to obtain a licence to discharge waste a number of additional investigations will be required. The potential mixing zone will need too be defined and this will likely require additional near field and mid field modelling of the new discharge location. This modelling will need to accommodate seasonal differences in currents and weather patterns as well as the local topography of the sea floor. There will likely be a program of collection of field measurements required by the EPA to calibrate and validate the models.

Additional toxicity testing may also be required to establish the potential impacts of the discharge on the local marine life.

A.8 Environmental Effects Act 1978 The Environmental Effects Act 1978 provides for an assessment of major projects that have the potential to have a significant impact on the environment. The Act does this by enabling the Minister for Planning and Community Development to decide that an Environment Effects Statement should be prepared. An EES may typically be required when:

There is a likelihood or regionally is State significant environmental effects;

There is a need for integrated assessment of potential environmental effects, including social and economic impacts, or a project and alternatives; and

Normal statutory processes would not provide a sufficiently comprehensive, integrated and transparent assessment.

Based on discussions with MWC and a preliminary assessment of potential impacts of the proposed project, an appropriately conservative position is to allow for the possibility that an EES will be required for this project.

A.9 Conclusions Regarding Environmental Impacts and Permitting. Option 1 would likely require the disturbance of areas surrounding the existing drop structure some 80 to 90 metres from the sea. This is an area of high environmental sensitivity from an archaeological point of view although the existing level of disturbance that exists would perhaps mean that vegetation clearance at this actual site may be manageable. Access for both transport and power may require additional vegetation clearance along the existing access track. The archaeological issues at this site may make permits very difficult to obtain.

Option 2 requires considerably less vegetation clearance than Option 1 and the vegetation to be cleared in of much lower conservation significance as the site is already cleared for the construction of the golf course. There may still be a requirement for Net gain offsets but these are likely to be small compared to those for Option 1. The potential impacts on local archaeology of a construction site at the golf course are likely to be less than at the site immediately behind the dunes (Option 1).

A summary of legislation, which may result in the need for approvals, is listed in Table A-5

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Table A-5 Summary of legislation, which may result in the need for approvals.

Legislation Likely Action Required Comment

Commonwealth

EPBC Act 1999 Referral will be required to Commonwealth.

It is unlikely that any additional actions may be required under the EPBC alone but the Commonwealth may require some involvement in any Victorian EES process. Applies to both options.

Victoria

Environment Effects Act 1978 Referral to Minister of Planning likely to be required to determine whether an EES may be required or not.

There are several triggers that may require an EES that may apply to this project. Applies to both options.

Coastal Management Act 1995 Consent will be required under the Act for works to be undertaken.

Applies to both options.

Planning and Environment Act 1987

A planning permit is likely to be required.

Under Victoria’s Native Vegetation Management Framework, administered through the P&E Act, a Net Gain assessment will be required.

A Net Gain assessment will be required. Applies to both options.

Environment Protection Act 1970

A licence to discharge will be required. This is in addition to any existing or new works approval that may be in place or obtained.

In order to obtain a licence to discharge, MWC will need to establish that the discharge will comply with the requirements of SEPP (WoV).

Compliance with the requirements of the SEPP (WoV) will require ecotoxiocology investigations, detailed hydrodynamic modelling and investigations of the marine ecology and fisheries of the area. The hydrodynamic modelling will require calibration and validation. Applies to both options.

Aboriginal Heritage Act 2006 A Cultural Heritage Permit (CHP) will be required for any works on land.

The permit will require detailed investigations including potentially sub-surface investigations. Applies to both options.

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A.10 Estimated Cost of the Environmental, Planning and Cultural Heritage Investigations

A cost estimate for the approvals phase of the project is presented in Table A-6. This cost estimate does not include the costs of:

Compliance monitoring after the Outfall Extension has been constructed;

The costs of a panel or other inquiry should an EES be required including legal fees.

A.10.1 Costs of Net Gain Offsets

The vegetation to be removed is almost entirely Alkaline Coastal Scrub, this EVC is considered vulnerable in the Gippsland Plains Bioregion and as such any habitat score of 0.5 or greater will result in the vegetation being considered to be of Very high Conservation Significance. It is very likely that this vegetation will have a habitat score in excess of 0.5. Vegetation of Very high Conservation Significance requires “like for like” offsets, that is the same EVC in the same Bioregion. Very High Conservation Significance vegetation also allows only 10% of the offset to be achieved through revegetation.

Offsets will need to be found through the purchase or reserving of land upon which Alkaline Coastal Scrub is found. Improvement in the condition of this EVC on the offset land will need to occur to provide the offsets required for the project. As there is a limited supply of land with Alkaline Coastal Scrub in the Gippsland Plains Bioregion and as most of this EVC which remains is in relatively good condition the opportunity for finding offsets is limited.

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Table A-6 Estimated Cost ($) of the Environmental, Planning and Cultural Heritage Approvals for both Options 1 and 2.

Activity Option 1 Option 2

Review Existing Information 50,000 50,000

Assess feasibility of Approvals 10,000 10,000

Negotiations with Approval Agencies 50,000 30,000

Terrestrial Flora and Fauna Survey 65,000 35,000

Net Gain Prelimiary Assessment of Liabilites 45,000 25,000

Marine Ecology Survey 250,000 250,000

Archaeology Survey 150,000 80,000

Referral to DPCD to determine whether EES is required 250,000 250,000

EPBC Referral 65,000 65,000

Production of EES (excluding panel) 2,200,000 1,600,000

Planning Permits Application 100,000 60,000

Water Quality Sampling to support WAA 250,000 250,000

Hydrodynamic modelling to support WAA 750,000 750,000

Cultural Heritage Management Plan 250,000 120,000

Works Approval Application 200,000 200,000

Fee for Works Approval Application (Standard EPA fee) 50,000 50,000

Net Gain Offsets - identification of offset locations 100,000 45,000

Net Gain - negotiations with insitutional stakeholders 35,000 35,000

Net Gain - development of offset plans 50,000 30,000

Purchase of Net Gain offsets 350,000 100,000

Management of Net Gain Offsets 150,000 80,000

Development of Environmental Management Plans 100,000 80,000

TOTAL 5,520,000 4,195,000

Allow say 5,500,000 4,200,000


Appendix B

Geotechnical Investigations

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Contents

B. Geotechnical Investigations 1

B.1 General 1 B.2 Aims and Objectives 2 B.3 Stage 1: Onshore Geotechnical Investigation 3 B.4 Stage 2: Horizontal Core Drilling (HCD) Investigation 3 B.5 Stage 3: Offshore Geotechnical Investigation 5 B.6 Proposed Offshore Methodology 5 B.7 Investigation Constraints 8 B.8 Key Outputs 9 B.9 Cost Estimate of the Geotechnical Investigations – Option 1 and

2 9

Figure Index Figure B-1 Diagram of a combined sub-bottom profiling system

and side-scan sonar 6 Figure B-2 Offshore Seismic Data Acquisition Procedure 7 Figure B-3 Jack-up barge in operation 8

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B. Geotechnical Investigations

B.1 General The identified geotechnical investigations for the SEO Extension, including cost estimates, are presented below.

The essential elements of the identified geotechnical investigations for the two options are listed in the table below. The reasons for the adopted approach are discussed below.

Type of Geotech Investigation

Option 1 Option 2

Stage 1 Onshore Geotechnical

Limited to one borehole at the location of the Option 1 shaft, i.e. in the National Park.

Limited to one borehole at the golf course for the shaft.

Stage 2 HCD Investigations. 2000 m is identified, but may not be achieved.

HCD starts at the last existing drop structure, i.e. in the National Park. Requires 1 ha construction site.

HCD starts at the golf course. Requires 1 ha construction site at golf course, which will become the construction site for the works.

Stage 3 Offshore (common to both Option 1 and 2)

Activities such as geophysics, boreholes obtained form a jack-up barge, bathymetric chart.

In order to reduce the risk associated with tunnelling, it is highly desirable to obtain horizontal cores. This type of information can identify areas of broken rock that may not identified up by a series of vertical boreholes.

For Option 1, one construction site will be required at the last existing drop structure, which is in the Mornington Peninsular National Park, i.e. where the shaft will be constructed. On this basis, starting a HCD exercise at this location does not impose any additional disturbance to the vegetation.

However Option 2, which has the advantage of not undertaking permanent works between the coast and the golf course, starting a HCD investigation at the Option 1 shaft location would involve additional vegetation clearance in the National Park. GHD does not recommend undertaking tunnelling without horizontal cores, however, on the basis that the environmental approvals may be difficult to obtain, the HCD exercise starting in the National Park has not been identified for Option 2. Instead, the starting point is at the golf course. The Option 2 HCD investigation alignment will not be able to extend the full length of the tunnel, even if it attains the identified length of 2000 m.

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Scope of Investigation

For both options, it is considered that a staged geotechnical investigation will be the most cost effective investigation approach for this project. Dividing the works into a number of consecutive stages also aids in achieving consistency between the various investigation methodologies. The scope of the proposed geotechnical investigation shall be divided into three stages:

Stage 1: Onshore Geotechnical Investigation

Stage 2: Horizontal Core Drilling (HCD) Investigation

Stage 3: Offshore Geotechnical Investigation

The scope of works and investigation methodology for these stages are outlined in Section B.3 to B.5 below.

Note, because of the exploratory nature of the geotechnical investigation, it is probable that some modification to the scope of work will be required as data acquisition proceeds and results are reviewed.

B.2 Aims and Objectives The staged investigation is designed to provide the following information:

Cores along the alignment of the tunnel. However, for Option 2 this will not be possible for the entire length because the HCD drilling technique will not be able to progress for the approximately 3 200 m length of tunnel. Even for Option 1, it may not be possible to achieve the identified objective of 2000 m of HCD drilling, particularly if adverse ground conditions are encountered.

Distribution of subsurface formations.

Strength and engineering characteristics of subsurface formations.

Presence of structures within subsurface formations that may present geological hazards to tunnel construction.

Permeability of rock mass in formations.

Onshore geological plan.

3-D geological model with offshore projection along the alignment of the outfall extension.

Hydrogeological model.

Water depth and Bathymetry.

Near surface soil conditions and their lateral variation.

Debris or man-made hazards across the proposed site.

The objective of the onshore geotechnical investigation (Stage 1) would be to extend knowledge of the subsurface profile to allow 3-dimensional geological and geotechnical modelling of the shaft site, onshore tunnel alignment and ancillary structure footprints.

The objective of the HCD (Stage 2) and offshore (Stage 3) geotechnical investigations would be to obtain sufficient reliable seabed information on the site conditions to permit the safe and economic design of installation and permanent works.

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Unexpected or poorly defined site conditions are one of the most commonly re-occurring causes of construction delays and cost escalations. By undertaking a detailed site investigation – as part of an integrated seabed risk management process - the risk of delays and increased costs would be reduced.

Offshore projects can be particularly exposed to seabed risk due to the relatively wide spacing of individual structures and the increased influence of metocean conditions in shallow water. In addition, projects are often located in areas where there is little or no existing knowledge of the seabed or environment.

B.3 Stage 1: Onshore Geotechnical Investigation The onshore investigation scope may include the following:

A desktop study to review the existing available geotechnical information in the vicinity of the proposed outfall extension.

A single 70 m onshore borehole to be drilled at the proposed location of the shaft in the national park (Option 1 only).

A single 70 m onshore borehole to be drilled at the proposed location of the shaft in the golf course (Option 2 only).

Downhole testing, including geophysical logging, groundwater level monitoring and packer testing.

Laboratory testing of the recovered core to recover basic rock strength parameters.

Laboratory testing of the recovered soil samples to recover basic soil characteristics and strength parameters.

Laboratory testing of the recovered soil samples to recover exposure classification and waste soil disposal parameters.

A limited amount of geological mapping of the surface exposures in the vicinity of Boags Rocks.

It is suggested that the borehole be drilled by a local drilling contractor.

The issue of vegetation clearance for undertaking the boreholes is addressed in Appendix A of this report.

B.4 Stage 2: Horizontal Core Drilling (HCD) Investigation The purpose of the proposed investigation program is primarily to provide information to tunnel designers and assist tunnelling contractors and to assess the need for sidewall support. Information on the rock mass that would be collected along the tunnel horizon includes:

Hardness and abrasivity.

The degree of weathering.

The presence, orientation and nature of jointing and faulting.

Rock mass permeability.

The presence and characteristics of basaltic dykes encountered during shoreline mapping.

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The scope of the HCD program would include:

Drilling one (1) borehole along the proposed outfall extension alignment. The hole is proposed to commence at the future site of Option 1, i.e. approximately 85 m from the coast, and progress to a total length of 2000m, if attainable. The diameter of the hole would be up to 100mm.

Alternatively, Drilling one (1) borehole along the proposed outfall extension alignment. The hole is proposed to commence at the future site of Option 2, i.e. in the golf course, and progress to a total length of 2000m, if attainable. The diameter of the hole would be up to 100 mm.

Laboratory testing of the recovered core to recover basic rock strength parameters and parameters specific to tunnel design and construction.

Laboratory testing of the recovered soil samples to recover basic soil characteristics, strength parameters and deformation characteristics.

Downhole testing, including geophysical logging and packer testing.

Geotechnical HCD drilling involves the establishment of a drill rig on a works site of approximately 100 by 100 metres, which includes the land to feed the drilling pipe into the drilling machine and drill hole. Photographs of typical HCD works sites are shown in Figure B-1. The drill rig will be located at the same site of the future Option 1 or Option 2 construction works.

Figures B-1: Horizontal Directional Drilling Equipment

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The cost estimate is based upon relevant and recent experience.

B.5 Stage 3: Offshore Geotechnical Investigation It is suggested that the offshore site investigation would comprises :

1. Offshore Geophysical Survey (Refractive).

2. Offshore Geotechnical Borehole Investigation.

Details of the offshore geophysical survey and offshore geotechnical borehole investigation are provided in Section 6.6.1 and Section 6.6.2, respectively.

B.5.1 Offshore Geophysical Survey

The prime objectives of undertaking a geophysical survey are as follows:

To provide an accurate bathymetric chart of the development area and tunnel routes.

To chart natural seabed features and any obstructions, debris or wrecks.

To produce isopach charts to show sediment thickness of the upper, loose, and any mobile material, and of any other significant reflector levels, which might impact on the engineering design.

To locate any structural complexities or geohazards within the shallow geological succession such as faulting, accumulations of shallow gas, buried channels etc.

To provide detailed geological interpretation to show facies variations and structural feature changes via appropriate maps and sections.

To allow for the design of a geotechnical sampling and testing programme following the completion of the geophysical survey.

To enable the production of a comprehensive interpretative report on the survey results obtained to assist in the design of the offshore outfall sewer and associated foundations / structures.

The geophysical survey to be undertaken would depend upon the requirements of the survey, water depths and any other physical restrictions. Typically for an echo sounder, side scan sonar, and a sub bottom profiler data would be recorded along survey lines spaced at 50m intervals with cross lines every 250m. Swathe data would be recorded along lines spaced no less than 3 times water depth. It is also advised that magnetic, resistivity and electromagnetic data be recorded along lines as closely spaced as is feasibly possible.

B.6 Proposed Offshore Methodology

Sub-bottom Profiling In order to provide further information on layers above bedrock, it is suggested the investigations use an acoustic reflection method to provide information on the layers above bedrock and to assist correlation of geological layers between boreholes.

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Sub-bottom profiling systems identify and measure various sediment layers that exist below the sediment/water interface. These acoustic systems use a technique that is similar to simple echo sounders. A sound source emits a signal vertically downwards into the water and a receiver monitors the return signal that has been reflected off the seabed. Some of the acoustic signal will penetrate the seabed and be reflected when it encounters a boundary between two layers that have different acoustical properties (acoustic impedance). The system uses this reflected energy to provide information on sediment layers beneath the sediment-water interface.

Acoustic impedance is related to the density of the material and the rate at which sound travels through the material. When there is a change in acoustic impedance, such as the water-sediment interface, part of the transmitted sound is reflected. However, some of the sound energy penetrates through the boundary and into the sediments. This energy is reflected when it encounters boundaries between deeper sediment layers having different acoustic impedance. The system uses the energy reflected by these layers to create a profile of the sub-bottom sediments Figure B-1

Bottom Seismic Refraction Data Acquisition Method Seismic refraction testing is also suggested for offshore.

A schematic diagram of the data acquisition methodology suggested for the survey is presented below in Figure B-2.

The shots would be acquired using a seismic airgun. Seismic airguns generate sound impulses by expelling bubbles of air. For survey work at this site a single 20-cubic inch air gun would probably be used as a seismic source at an operating pressure of 600 to 1000 psi. Shots would be fired at a rate of up to 10 shots an hour.

Single airguns used in geological surveys to map sea floor profiles typically expel 30 to 800 cubic inches of air per shot. For oil and gas exploration, air gun arrays are used. These arrays consist of 12-48 individual airguns synchronized to create a simultaneous pulse of sound, outputting a total of 3000-8000 cubic inches of air per shot. Shots are typically fired every 10 to 15 seconds.

From the above it will be apparent the energy source suggested for the investigation is many magnitudes smaller than that used in oil well exploration.

Manufacturers data shows that the maximum noise output from the suggested airgun is rated at 173 dB re 1 µPa at 2000 psi. It is likely the airgun would be operated at less than half this rated pressure.

B-1 Diagram of a combined sub-bottom

profiling system and side-scan sonar

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The air gun would only be used when positioned near the seabed floor and the test array would be essentially static during each test. Shots would be progressively ramped up to mitigate adverse effects on marine life. A visual survey would be carried out before testing commences to check for the presence of whales within 1km of the survey location.

It is likely the data acquisition would be performed using two boats - a bigger one - to carry heavy survey equipment: and a smaller boat for the acquisition system.

It is likely the geophones / hydrophones would be precisely positioned using GPS Trimble Pro XRS navigation unit (System claimed lateral accuracy: + /_ 0.50 m.

B-2 Offshore Seismic Data Acquisition Procedure

B.6.1 Offshore Geotechnical Borehole Investigation

The offshore geotechnical borehole investigation would provide additional sub-seabed data to allow detailed design of the project including tunnelling, and associated foundations and riser protection. To add maximum value to the seabed risk management process the geotechnical investigation data would be correlated with the preliminary site assessment (desk study) and the findings of the geophysical survey. The aim of the investigation is to confirm the geological / geophysical model for the site, determine the vertical and lateral variation in seabed conditions and to provide the relevant geotechnical data for design.

The scope of the offshore geotechnical borehole investigation may include:

Drilling ten (10) vertical boreholes to a maximum depth of 50m below the seabed utilising a jack up barge. The holes may be positioned along the proposed outlet tunnel alignment, at riser locations, and any anomalies identified from the regional geological maps. The bores would be designed to recover core samples (PQ wire line - 83 mm diameter) to full depth.

Laboratory testing of the recovered core would be undertaken to recover basic rock strength parameters and parameters specific to tunnel design and construction.

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Laboratory testing of the recovered soil samples would be undertaken to recover basic soil characteristics, strength parameters and deformation characteristics.

Down hole testing, including geophysical logging, groundwater level monitoring and packer testing would be undertaken.

Jack-up barges are three or four legged mobile platforms (or barges) that can be towed into place offshore, with legs that are then lowered to the ocean floor. An indication of the type of barge that could be used is shown in Figure B-3 below. Once in place, the barge performs the roll of a drilling rig to construct bores to take samples and perform seismic and other geotechnical investigations.

B-3 Jack-up barge in operation

Jack up movements can be significantly affected by waves. Scheduling offshore drilling when wave heights are lowest (between 2 and 3m) with a large jackup rig would maximise the chances of completing the proposed drilling programme successfully. Availability of such rigs is generally low and, as such the rig would need to be ordered well in advance of the proposed drill date.

B.7 Investigation Constraints A number of key logistical and technical constraints have been identified. These include:

Permits to access coastal area for drilling.

Surface geophysics access to beach.

Drilling site controls and site clean-up issues.

Stability of investigation bores for conducting borehole geophysics and permeability testing to the desired standards.

Well completion procedures.

Cultural heritage issues within coastal zone.

Flora and Fauna Issues within the coastal zone.

Availability of the HCD rig and suitable Jack up Barge.

Weather conditions producing swells in excess of the tolerable limit of the Jack up Barge.

Delays caused by community and environmental objection to the proposed outfall extension.

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Additional onshore investigation may include further drilling, or further onshore seismic refraction and/or reflection testing. It is anticipated that the requirement and design of this further drilling and seismic testing would be assessed following review of the onshore investigation results.

B.8 Key Outputs The key outputs from the geotechnical investigation described above would typically comprise:

Definition of key geological processes and their status (e.g. active, dormant etc).

Estimated met ocean conditions.

Refined geological model including the determination of the variability and lateral extent of any variation in ground conditions.

Idealised ground profile along the proposed tunnel alignment location.

Geotechnical parameters to allow detailed design.

Identification of geotechnical hazards and quantification of risk.

B.9 Cost Estimate of the Geotechnical Investigations – Option 1 and 2 It should be noted that the estimated cost of the identified geotechnical investigations is the same for both Options. This is because the only difference is the location of the HCD investigation, i.e. for Option 1 it would start in the National Park, and for Option 2, it would start at the golf course.

B.9.1 Borehole and Field Mapping

Activity Description Cost Estimate ($)

1. Geological Mapping 1.1 Field Mapping and Reporting $ 4 600

SUBTOTAL $ 4 700

2. Shaft Investigation (Includes GHD Logging and Overseeing)

2.1 Drill 1 Borehole to 70m Depth $ 42 300

2.2 Field and Laboratory Testing $ 5 700

2.3 Borehole Geophysical Logging $ 20 700

2.4 Permeability Testing $ 11 600

SUBTOTAL $ 80 300

3. Reporting 3.1 Provide Draft Results at Completion of Field Work

$ 100 000

3.2 Provide One Copy Each of Draft Interpretative and Factual Reports for Review

$ 200 000

3.3 Provide Three Copies of Final Interpretative and Factual Report

$ 65 000

SUBTOTAL 365 000

TOTAL $ 450 000

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B.9.2 Cost Estimate – HCD Geotechnical Investigation


1. Drilling 1 Borehole to 2000m using Horizontal Coring Technique

1.1 Preparation and Mobilisation $ 1 600 000

1.2 Operational Drilling Costs (Including Standby, Accommodation and Daily Travel)

$ 7 900 000

1.3 Insitu Testing and Consumables $ 2 700 000

SUBTOTAL $ 12 200 000

2. GHD Logging and Overseeing 2.1 GHD Time and Expenses $ 500 000

SUBTOTAL $ 500 000

3. Laboratory Testing 3.1 Soil and Rock Laboratory Testing $ 200 000

SUBTOTAL $ 200 000

4. Reporting 4.1 Provide Draft Results at Completion of Field Work

$ 150 000


$ 225 000


$ 75 000

SUBTOTAL $ 450 000

TOTAL $ 13 350 000

B.9.3 Cost Estimate - Offshore Geotechnical Investigation


1. Drilling 10 Borehole to 50m off a Jack Up Barge along Outfall Tunnel Alignment

1.1 Preparation and Mobilisation $ 700 000

1.2 Operational Drilling Costs (Including Standby, Accommodation and Daily Travel)

$ 4 100 000

1.3 Insitu Testing, Consumables and Third Party Services

$ 1 000 000

SUBTOTAL $ 5 800 000 2. GHD Logging and Overseeing

2.1 GHD Time and Expenses $ 600 000

SUBTOTAL $ 600 000

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3. Laboratory Testing 3.1 Soil and Rock Laboratory Testing $ 200 000 SUBTOTAL $ 200 000 4. Offshore Geophysics 4.1 Sub-bottom profiling and Bottom Seismic

Refraction $ 850 000

SUBTOTAL $ 850 000 5. Reporting 5.1 Provide Draft Results at Completion of Field

Work $ 150 000


$ 225 000


$ 75 000

SUBTOTAL $ 450 000 TOTAL $ 7 950 000

The estimated geotechnical investigation costs for both options with sub-totals for each of these stages is presented below:

Stage 1 : Onshore Investigations $0.45 million

Stage 2: HCD Geotechnical Investigations $13.35 million

Stage 3 : Offshore Geotechnical Investigations $7.95 million

Total $21.75 million


GHD

180 Lonsdale Street Melbourne, Victoria 3000 T: (03) 8687 8000 F: (03) 8687 8111 E: [email protected]

© GHD 2009

This document is and shall remain the property of GHD. The document may only be used for the purposes for which it was commissioned and in accordance with the Consultancy Agreement for the commission. Unauthorised use of this document in any form whatsoever is prohibited.

Document Status

Reviewer Approved for Issue Rev No. Author

Name Signature Name Signature Date

G Mallory G Mallory

S Young

18/3/09

Report for South Eastern Outfall Extension · 2. Description of the South Eastern Outfall 2 3....

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