Lower Brown Hill Creek and Keswick Creek Upgrades

Concept Report

Brown Hill Keswick Creek Stormwater Project

March 2016

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Document History and Status

Rev Description Author Reviewed Approved Date

A Draft for Client Comment CLB MdeH December 2015 B Issued for final review CLB MdeH MdeH March 2016

© Tonkin Consulting 2015 This document is, and shall remain, the property of Tonkin Consulting. The document may only be used for the purposes for which it was commissioned and in accordance with the Terms of Engagement for the commission. Unauthorised use of this document in any form whatsoever is prohibited.

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Contents

1 Introduction 2 1.1 Background Information 4 1.1.1 Brown Hill and Keswick Creek Survey and Hydraulic Assessment, 2012, AWE 4 1.1.2 Stormwater Management Plan, 2012, WorleyParsons 4 1.1.3 Part B Report, BHKCSP WorleyParsons 4 1.2 Existing Channel Characteristics 5

2 Previous Investigations 6 2.1 LBHC Main Channel Upgrade (Anzac Highway to Watson Avenue) 6 2.1.1 Stage 1 Engineering Feasibility Report, Draft 2013/Interim 6 2.1.2 Stage 1 Limited Environmental Site History – LBHC, 2013 7 2.1.3 Lower Brown Hill Creek Channel Upgrade – Channel Assessment - Revised Hydrology, 2013, Tonkin Consulting 8 2.1.4 Revised Hydraulic Modelling (2015), WorleyParsons 8 2.2 Keswick Creek Diversions 10 2.2.1 Keswick Creek to Brown Hill Creek Diversions, Tonkin Consulting 10 2.2.2 Stormwater Management Plan, 2012, WorleyParsons 12 2.2.3 Keswick Creek Diversion – Options Report, 2013, Tonkin Consulting 12 2.2.4 Keswick Creek Bypass (City of West Torrens) Options Report, 2013, Tonkin Consulting 12 2.2.5 Lower Brown Hill Creek Channel Upgrade – Channel Assessment - Revised Hydrology, 2013, Tonkin Consulting 13 2.2.6 WorleyParsons Revised Hydraulic Modelling (2015) 13 2.2.7 Anzac Highway Culvert Review, 2015, Tonkin Consulting 14

3 Concept Plan 15 3.1 Engineering Survey and Project Chainages 15 3.1.1 Lower Brown Hill Creek Chainages 15 3.1.2 Keswick Creek Chainages 17 3.1.3 Chainage Discrepancies 17 3.2 Water and Sewer Services 17 3.3 Showgrounds Development 17 3.4 Workshop and Site Inspection 17 3.5 Concept Design 18

4 Cost Estimate 20 4.1 Scope 20

5 Recommendation 23 5.1 Preferred Concept 23 5.2 Recommendation 23

6 References 24

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Tables Table 4.1 Cost Estimate – March 2016 22

Figures Figure 1.1 Locality Plan 3 Figure 2.1 Extent Lower Brown Hill Creek Upgrades 9 Figure 2.2 Keswick Creek Diversion Options 11 Figure 3.1 Chainage Comparison 16

Appendices Appendix A Existing Creek Characteristics Appendix B Photos – Creek walkthrough December 2015 Appendix C Recommended design flow rates (Scenario #31, December 2015) Appendix D Concept Design Drawings Appendix E Cost Estimate (Costplan)

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1 Introduction Tonkin Consulting was engaged by the City of Unley on behalf of the Brown Hill Keswick Creek Stormwater Project (BHKCSP) for the catchment councils of Adelaide, Burnside, Mitcham, Unley and West Torrens, to undertake an options and feasibility study for the upgrade of lower Brown Hill Creek (LBHC) downstream of Anzac Highway. The project is required to contain a 100 year ARI stormwater flow within the main channel and the diversion of a portion of the Keswick Creek flow into lower Brown Hill Creek at Anzac Highway. Lower Brown Hill Creek extends for a length of 3300 metres from Anzac Highway to its confluence with Keswick Creek on the south eastern side of Adelaide Airport at Netley. Keswick Creek starts from the confluence of Parklands Creek and Glen Osmond Creek at Wayville and extends through the western suburbs until it joins Brown Hill Creek at Netley on the south eastern side of the Airport. The diversion of portion of the flow from Keswick Creek into lower Brown Hill Creek at Anzac Highway is an integral part of the overall flood mitigation solution proposed in the 2012 stormwater management plan (refer Section 1.1.1) and is included in this report. A number of reports have been prepared regarding the technical and broader impacts of the lower Brown Hill Creek upgrade including the Keswick Creek diversion. The intention of this report is to concisely summarise the historical reports produced to date and outline the current preferred solution (at concept planning level) for the Lower Brown Hill Creek and Keswick Creek upgrades to accommodate the 100 year peak flow from the combined catchments. The locality plan is presented in Figure 1.1.

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Figure 1.1 Locality Plan

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1.1 Background Information The Brown Hill and Keswick Creek catchment has been reported on for a number of years. A significant flood mitigation study was presented in the Brown Hill and Keswick Creeks Flood Mitigation Study Flood Management Master Plan (Hydro Tasmania, 2006) for the Patawalonga Catchment Water Management Board (now part of the Adelaide and Mount Lofty Ranges Natural Resources Management Board). Two further studies have been carried out on the catchment for the BHKCSP, as described below. In 2010, the BHKCSP engaged WorleyParsons to revise the 2006 Master Plan. The resulting report (dated August 2012) was approved by the Stomwater Management Authority (SMA) as the Stormwater Management Plan (SMP) for the catchment in 2013 (the ‘2012 SMP’). In developing the 2012 SMP WorleyParsons, in accordance with its brief, subcontracted the floodplain modelling to Hydro Tasmania Consulting (HTC). The two dimensional floodplain model used for the catchment investigations of the 2006 Master Plan and the 2012 SMP was developed and run by HTC using the Mike-FLOOD proprietary software. In mid-2013, the BHKC project had the model transferred to WorleyParsons with the role to upgrade and run the model for all investigations involving Brown Hill and Keswick Creeks.

1.1.1 Brown Hill and Keswick Creek Survey and Hydraulic Assessment, 2012, AWE A Channel Capacity Assessment report of lower Brown Hill Creek and Keswick Creek (including Parklands Creek and Glen Osmond Creeks as tributaries to Keswick Creek) was completed in 2012 by Australian Water Environments (AWE) for the Adelaide and Mount Lofty Ranges Natural Resources Management Board (AMLRNRMB). A comprehensive survey of the four creeks and channel capacity estimates were last undertaken in 1983 (by WBCM). A one dimensional hydraulic model was used to estimate the flows that could be contained within the banks of the creeks. The model used surveyed cross sections collected by Hennig and Co along with observations made through a series of field inspections to assign model parameters.

1.1.2 Stormwater Management Plan, 2012, WorleyParsons The 2012 SMP covers the whole of Brown Hill Creek. That report defines the design flow for Lower Brown Hill Creek main channel as 60m3/s, which includes stormwater flow diverted from the Keswick Creek. The proposed channel upgrade (for the purposes of capacity assessment and costing) was a vertical-sided concrete lined channel 8m wide by 2m high but it was noted that there are alternatives which may be more acceptable to the community. It also identified that property acquisition and bridge upgrades would be required.

1.1.3 Part B Report, BHKCSP WorleyParsons The 2014 Part B report describes the works essentially upstream of Anzac Highway (‘upper Brown Hill Creek’). A critical element of this report is that it describes the 2013 updated hydrology prepared by the Department of Planning Transport and Infrastructure (DPTI). The updated hydrology is an outcome of updates to the 1987 Australian Rainfall and Runoff IFD data (as used in the 2012 SMP) together with an allowance for storage in the catchment and has resulted in lower peak flows generally throughout the catchment, including peak flows in Brown Hill and Keswick Creeks arriving at Anzac Highway.

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1.2 Existing Channel Characteristics The characteristics of the existing LBHC downstream of Anzac Highway and Keswick Creek channel segments have previously been summarised and documented. This summary (updated to match the consistent project-wide chainages) is provided in Appendix A. A detailed creek walkthrough from Anzac Highway downstream to the Keswick Creek confluence was undertaken in December 2015 in which the concepts developed were reviewed against the channel characteristics. Appendix B includes a series of photos from the walkthrough.

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2 Previous Investigations

2.1 LBHC Main Channel Upgrade (Anzac Highway to Watson Avenue) As part of the feasibility study for the LBHC upgrade the following reports have been prepared:  Draft Channel Upgrade Stage 1 Engineering Feasibility (Tonkin Consulting 2013)  Stage 1 Limited Environmental Site History (Tonkin Consulting 2013)  Revised Hydrology Channel Options (Tonkin Consulting 2014)  Channel Upgrade Stage 1 Engineering Feasibility (Tonkin Consulting 2014)  Revised Hydraulic Modelling (Worley Parsons 2015)1  Lower Brown Hill Creek Channel Upgrade – Stage 1 Engineering Feasibility Report, Draft 2013/Interim 2014, Tonkin Consulting. The scope of the above reporting has included both technical and non-technical aspects of the upgrade of lower Brown Hill Creek.

2.1.1 Stage 1 Engineering Feasibility Report, Draft 2013/Interim The 2014 Interim report included a description of the existing creek including zoning, current land use, vegetation, services, transportation connectivity, amenity and channel treatment (natural earth, concrete, etc.), constructability, land ownership and easements. There are estimated to be about 21 significant or regulated trees within the study area, 10 of which are in Grassmere Reserve. Four local heritage features were identified: Ashford House School, Ashford Gum Tree Stump, Ashford Mature Oak and the Birdwood Terrace Railway Corridor. HEC-RAS one dimensional hydraulic modelling was used to determine the dimensions of various creek upgrades for the 60m3/s design flow. The upgrades proposed vertical-sided concrete channel, box culverts, gabion-lined stepped open channel and a trapezoidal earth-lined channel. A Multi-Criteria Analysis workshop was held as part of the study which ranked the earth channel as the higher preference, but with comparable scores for all options. A summary of the geometry of these options is presented in the following table:

Option Geometry Concrete Channel 7m wide x 2.1m high Culvert 9m wide x 1.8m high Gabion Channel 10m base width, 2m high Earthen Channel 6m base, 1:4 side slopes

Whilst the earth channel was ranked highest it was discounted due to the significant amount of property acquisitions and the social impact. Initial community engagement as part of the feasibility study included articles in the local papers and community newsletters, letters to nearby residents and community information displays. Feedback from local residents identified flood mitigation and improving water quality were preference outcomes of the upgrade.

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2.1.2 Stage 1 Limited Environmental Site History – LBHC, 2013 Tonkin Consulting undertook a Staged Environmental Site History (ESH) for the alignment of and the properties adjacent the proposed Lower Brown Hill Creek (LBHC) upgrade. At the time of the report there were approximately 243 individual adjacent land allotments. The objectives of the Stage 1 Limited ESH were to provide an assessment of potential site contamination concerns along the creek and develop an initial risk ranking for site contamination potential for the subject lands. This would be used to inform the scope of any potential future phases of the Staged ESH process. A site inspection and desktop assessment were undertaken. A risk rating for Potentially Contaminating Activities (PCA) was developed which included  Creek construction and bank construction (concrete lined sections and modified creek segments)  Filling  Stormwater outfalls  Waste dumping (soils, vegetation and rubbish)  Standing water. Contaminates of Potential Concern (COPC) were identified for the PCAs and include Petroleum hydrocarbons, (including PAHs, TPH, phenolics and VOC’s), Heavy metals, Solvents, Pesticides, Herbicides and Termidicides and Asbestos. The predominant land use of the 243 adjacent allotments along the 3.3 km alignment of LBHC subject to this investigation has been residential from the 1950s to current. It is assumed that for the majority of these residential properties the site contamination potential associated with their current and historic use is generally moderate to low. There are however a limited number of current and former commercial / industrial properties located adjacent to the creek which may represent locations where PCAs may have, or are currently occurring. Eleven allotments were identified as being of high site contamination potential (risk ranking ‘5’). These allotments are;  Allotment 752 –Located on the southern side of the LBHC alignment directly west of Marion Road  Allotments 826 & 827 – Located on the corner of Dudley Ave and Marion Road.  Allotments 342, 438, 439, 440, 441 and 1,075 - Six privately held properties located between Daly St and Gray Street  Allotments 476 & 477 – Located where Selby St intersects the alignment. A total of 121 of the 243 allotments along the creek were identified as being of medium site contamination potential as a result of observed fill (building material, bitumen, rubbish), stormwater outfalls or dumping of material The remainder of the allotments were ranked as low although in areas where the creek is concrete lined and there is a risk that uncontrolled filling may have occurred behind the concrete lining. The information gained during this investigation has identified the widespread presence of fill as the most dominate PCA at the site. As such the generation of waste soil (as defined by the SA EPA) from this fill material and its subsequent classification for suitable onsite (or offsite) reuse and / or offsite disposal in accordance with the SA EPA Waste Derived Fill (WDF) guidelines is considered to represent the greatest potential site contamination risk (financial, project timing, human health and ecological) to the successful completion of the LBHC Upgrade Project.

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In order to gain a greater understanding of the extent of actual contamination at the site and to allow an effective refinement of the current site contamination risk ranking (including the establishment of a potential financial risk ranking based upon SA EPA WDF guidelines complying soil disposal options), it is recommended that a targeted intrusive classification of soils within the creek invert and banks be undertaken at all high risk and selected medium risk areas of the creek.

2.1.3 Lower Brown Hill Creek Channel Upgrade – Channel Assessment - Revised Hydrology, 2013, Tonkin Consulting In response to the revised hydrologic modelling, the technical aspects of the Stage 1 feasibility report were revised to reflect the new design flow in the main channel which had been decreased to 45.9m3/s. Indicative geometry for the LBHC main channel upgrade to meet this capacity was determined as follows:

Option Geometry Concrete Channel 5.5m wide x 1.8m high Culvert 2 units x 3.3m wide x 1.8m high Gabion Channel 7m base width, 2m high

The earth-lined channel was not considered as the property acquisition required to accommodate the top width of the channel would likely be met with significant opposition from the community. A number of “sub-options”, i.e. hybrids of other options, were also investigated.

2.1.4 Revised Hydraulic Modelling (2015), WorleyParsons WorleyParsons updated the hydraulic modelling based on sub-catchment inflows from DPTI (hydrologic modelling) and provided estimated peak flows in Lower Brown Hill Creek and Keswick Creek based on two dimensional Mike 21 flood modelling and one dimensional Mike 11 hydraulic modelling have been undertaken for both Keswick Creek and LBHC. The most recent design peak flows (December 2015) are presented in Appendix C for the ‘mitigation case’. That is, with all the upstream flood mitigation works of the 2012 SMP, the Part B Report and the proposed Keswick Creek diversion works (Section 2.2 below). The Keswick Creek diversion design flows have been calculated by WorleyParsons to reduce flooding in Keswick Creek downstream of Anzac Highway. WorleyParsons prepared plans showing the extent of works (February 2015) and cross sections documenting the anticipated scope of creek upgrades based on a design flow in LBHC of 46.9m3/s (reference WorleyParsons scenario #31 23/12/2015). In the modelling by WorleyParsons, approximately 70% of the total length is proposed to be increased in capacity (some involving only very minor widening of the base of the channel). Figure 2.1 shows the proposed extent of lower Brown Hill Creek upgrades.

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Figure 2.1 Extent Lower Brown Hill Creek Upgrades

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2.2 Keswick Creek Diversions At the upstream end of the original study area, flow from Keswick Creek is intended to be diverted into LBHC at Anzac Highway because, from the 2006 Master Pan and the 2012 SMP it is more feasible to increase the capacity of LBHC than Keswick Creek downstream of Anzac Highway. During the original feasibility investigation it was proposed that the study area be extended to the intersection of Le Hunte Street with Keswick Creek in Wayville, which is the furthest upstream Keswick Creek is diverted. The following reports have been prepared regarding Keswick Creek diversions:  Keswick to Brown Hill Creek Diversion Stage 1 and 2 (Tonkin Consulting, 2009 & 2010)  Keswick Creek Diversions Options Report (Tonkin Consulting, 2013)  Keswick Creek Bypass (City of West Torrens) Options Report (Tonkin Consulting, 2013)  Channel Assessment - Revised Hydrology (Tonkin Consulting, 2013)  Channel Upgrade Stage 1 Engineering Feasibility (Tonkin Consulting, 2014)  Anzac Highway culvert review (email, Tonkin Consulting, 2015)  Revised Hydraulic Modelling (WorleyParsons 2015).

2.2.1 Keswick Creek to Brown Hill Creek Diversions, Tonkin Consulting The 2006 Master Plan recommended two diversions along Goodwood Rd and the Railway corridor connecting Keswick Creek to Brown Hill Creek. The purpose of this was to reduce flows in Keswick Creek downstream of Anzac Highway to reduce flooding in the western suburbs. The scope of the following Stage 1 and Stage 2 reports was to investigate those proposed diversions, any alternative diversions and prepare preliminary designs for the preferred diversion alignments.

Stage 1 Report 2009 The Stage 1 Report investigated the feasibility and alignment selection of the Keswick Creek diversions. It reports on the unique landholders in the area, i.e. railway corridor, the showgrounds and the Army barracks, and the availability of land. The report presents alternative alignments for each of the diversions required by the Hydro Tasmania Master Plan, i.e. an offtake in Le Hunte St as an alternative for the Goodwood Rd Diversion and an offtake in Anzac Hwy as an alternative to the Railway corridor diversion. The report recommends that in both cases the alternative alignments are adopted for the following reasons:  Extending the diversion a short distance upstream of Goodwood Road to Le Hunte Street will address periodic inundation issues at Le Hunte Street and Joslin Street, and also ensures that the full 100 year ARI peak flow is able to be contained within this ‘limited capacity’ creek reach  A diversion at Anzac Highway is considerably shorter (520m) than the railway diversion (1000m) and hence should be considerably cheaper to implement  The capacity of the channel through the Keswick Barracks is close to the 100 year ARI flow (assuming the Le Hunte Street diversion is implemented). A diversion at the railway line, above the Barracks site, is not a requirement for protection of the barracks site, but rather for Keswick, Mile End and beyond. The required design capacity of the Goodwood/Le Hunte diversion is reported as 14m3/s; the required design capacity of the Railway/Anzac diversion is reported as 11m3/s. Figure 2.2 shows the key alignments investigated.

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Figure 2.2 Keswick Creek Diversion Options

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Stage 2 Report 2010 This stage of the investigation included hydraulic modelling (using DRAINS software) and identification of services using Dial Before You Dig. The services identified for relocation were a DN650 water main in Goodwood Rd and a DN150 gravity sewer. At Anzac Highway adjacent Keswick Creek shallow depth box culverts were proposed to avoid a DN 650 mm water main. The report discussed using a jacking method to install the culvert or pipe under the Leader St level crossing. As part of this investigation, boreholes were drilled on Anzac Hwy and the Showgrounds. Testing of soil samples from these boreholes identified contamination associated with traces of bitumen. The Anzac diversion culvert was designed as a 3.0x1.5m box culvert. The Le Hunte diversion culvert ranged in size but was primarily designed as a 3.3x1.5m box culvert. The report also included a project risk assessment which identified disruption to properties along the alignment as the highest risk to the project.

2.2.2 Stormwater Management Plan, 2012, WorleyParsons The 2012 SMP presented an abridged version of the 2009 and 2010 reports produced by Tonkin Consulting.

2.2.3 Keswick Creek Diversion – Options Report, 2013, Tonkin Consulting The purpose of this study was to investigate the Le Hunte diversion culvert alignment in light of (then) proposed works by the Department of Planning, Transport and Infrastructure (DPTI) at the Leader St level crossing. At the time it was envisaged that the section of culvert crossing the railway could be constructed in 2013 during a planned railway shut down. An analysis of hydrology, an analysis of hydraulics, the culvert alignment within Anzac Hwy and the culvert alignment upstream of the Showgrounds were all outside the scope of the investigation. The study investigated four different options for the diversion alignment:  Option 1: alignment along Maple Ave (i.e. further north) instead of Leader St, crossing the railway further north and passing through an existing building on the Showgrounds  Option 2: upgrade of Keswick Creek through the barracks, crossing the railway further north than Option 1 and again passing through an existing building on the Showgrounds  Option 3: alignment along Leader St mostly as per the 2010 Tonkin Consulting report with the railway crossing moved approximately 30m to the north to avoid a planned grade separated junction and a planned grade separated bike path  Option 4: adopting the 2010 alignment but with an inverted syphon underneath the Leader St level crossing to allow for the DPTI works. The report concluded that all options investigated are feasible, but Option 3 was preferred at that stage because it minimises disruption to residents, negotiations with major property owners and service relocations, whilst not introducing the maintenance and safety issues that would be associated with Option 4. No cost estimates were prepared as part of this study. Further site investigations and discussions with utilities would be required in order to confirm the assumptions regarding the required service relocations. Option 2 was identified as the second preferred option, the main disadvantage being that the extent of channel augmentation within the Keswick Army Barracks was unknown at the time.

2.2.4 Keswick Creek Bypass (City of West Torrens) Options Report, 2013, Tonkin Consulting The construction of a new bypass culvert (Keswick Creek Bypass – City of West Torrens) within the road network was proposed by the City of West Torrens (CWT) as an alternative to a full- scale upgrade of LBHC. The new bypass could receive flows from Brown Hill Creek and

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Keswick Creek at Anzac Highway to be discharged back into Brown Hill Creek downstream of Marion Road. Tonkin Consulting carried out a high level feasibility analysis of the proposed alignment. The main advantage of this option was that the existing LBHC main channel would not need to be upgraded except for sections with an existing capacity of less than 25 m3/s. A 4.2m x 1.8m bypass culvert was found to have a capacity of approximately 28m3/s. The total cost to provide a bypass culvert solution and upgrade LBHC to 24 m3/s capacity was estimated to be slightly higher than the estimated cost to upgrade LBHC alone to a 60 m3/s capacity. It was recommended that the bypass culvert option be further investigated if the total LBHC design flow is lowered to less than 52 m3/s. The cost estimate for the bypass culvert was considered to be pre-feasibility only and to determine a more accurate cost it was recommended that preliminary design be undertaken to confirm capacity and determine impact on services including liaison with service authorities. The bypass culvert would need to be constructed in its entirety to provide some flood protection benefit.

2.2.5 Lower Brown Hill Creek Channel Upgrade – Channel Assessment - Revised Hydrology, 2013, Tonkin Consulting As the hydrological study was evolving, the original LBHC feasibility study scope was extended to include Keswick Creek upstream of LBHC to Le Hunte St. The hydraulic modelling for the entire area was revised to address the lower design flows. The study investigated the Anzac Highway diversion, the 2010 Leader St alignment for the Le Hunte diversion and the barracks alignment (i.e. Option 2 from the previous 2013 study). The Anzac Hwy diversion was sized as a 2.7x1.5m box culvert to accommodate a capacity of 9.9m3/s. The report stated that to achieve adequate grade and avoid services, the upstream invert of this culvert in Keswick Creek should be raised and the downstream invert lowered which will require a portion of LBHC from Anzac Highway to Farnham St, Wayville to be lowered. The Le Hunte St diversion through the Showgrounds and along Leader Street, was sized as a 3.3x1.5m box culvert to accommodate a capacity of 12.6m3/s. The diversion alignment through the Barracks was also investigated and the culvert from Le Hunte via the Showgrounds to the Barracks was sized as a 3.0x1.5m box culvert to accommodate a 12.6m3/s design flow. The open channel within the barracks was found to have a capacity comparable to the design flow of 34.4m3/s, with bridge upgrades, mounding either side of the channel and other minor modifications required to accommodate the design flow.

2.2.6 WorleyParsons Revised Hydraulic Modelling (2015) Within the scope of its floodplain modelling brief with the BHKCSP, WorleyParsons determined the extent to which the open channel section of Keswick Creek through the Army Barracks needed to be upgraded to contain the peak 100 year ARI flow – with Le Hunte Street diversion feeding back into the channel (as shown in the plan layout of works). WorleyParsons also carried out a series of modelling simulations to optimise peak flows as between:  The transfer of flow through the proposed twin diversion culverts (along Anzac Highway) from Keswick to lower Brown Hill Creek  The residual flow continuing into lower Keswick Creek compared with its capacity at potential break-out areas along its length

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 The resulting peak flow in lower Brown Hill Creek, combining the diversions flow with the peak flow entering from upper Brown Hill Creek, contained to the creek’s upgraded capacity. A 2.0 metre diameter ‘choke’ is proposed by WorleyParsons in Keswick Creek downstream of the Anzac Highway diversion to limit flow into Keswick Creek. This would need to be modelled to ensure the correct split of flows between Keswick Creek and the Anzac Highway diversion. The revised hydraulic modelling is described in Section 2.1.4.

2.2.7 Anzac Highway Culvert Review, 2015, Tonkin Consulting In order to mitigate overflows from Keswick Creek downstream of Anzac Hwy, WorleyParsons proposed to increase the size of the Keswick Creek diversion (to Brown Hill Creek) along Anzac Highway in their modelling to twin 3.6m x 1.8m box culverts with redefined upstream and downstream elevations. Tonkin Consulting was engaged to comment on the feasibility of constructing these larger culverts in Anzac Highway. The investigation concluded that the construction of twin 3.6x1.8m box culverts was possible although with some risks. The investigation raised the following issues and observations:  The design requires lowering and flattening of LBHC from Anzac Highway downstream to Farnham Road (as a minimum). This section of creek has been identified as requiring a capacity upgrade regardless and the regrading and flattening of the grade will increase overall depth of the channel  At the Keswick Creek/Anzac Highway intersection, the available cover from natural surface to the top of the culvert would be approximately 100mm in the footpath and decreasing to no cover at the water table which is undesirable as would not allow an overlaid asphalt surface without road shaping  An existing DN650 water main at Keswick Creek crossing would result in the top of any new culvert sitting approximately 1.7 m below natural surface (without relocation of the water main), which is not considered to be feasible. The water main will need to be lowered at an approximate cost of $215,000-$275,000 (2015 estimate – Costplan) and due to the size, will likely need to be undertaken in winter. The 2010 concept design included a shallow depth transition structure to avoid the watermain. As part of preliminary design it is recommended that this water main is located and depthed and all culvert options reviewed to determine most cost effective solution  Numerous other services cross the proposed culverts and these will need to be adjusted to suit the new levels. Subject to the design at Keswick Creek, some services will need to be diverted under the new culverts at a depth of approximately 3m  The twin culverts entering LBHC at Anzac Highway will require land acquisition. The original concept included the diversion of the existing Anzac Highway culvert to the west to reduce the required land acquisition  There are a large number of trees in the median which will need to be removed. It is understood that some trees that would require removal may be memorial trees planted by the RSL  The works will require the intersection of Anzac Highway / Leader Street including traffic lights to be managed during site investigations and construction.

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3 Concept Plan

3.1 Engineering Survey and Project Chainages An engineering survey of the base of the Lower Brown Hill Creek was undertaken by Civil Surveys and Design in 2015. This survey identified the approximate centre line and the left and right bottom of bank which provides an overall creek base width and accurate centre line alignment.

3.1.1 Lower Brown Hill Creek Chainages Creek chainages were updated based on the survey and the updated chainages adopted in upper Brown Hill Creek. Currently there are three chainage systems in use being for lower Brown Hill Creek.  AWE (2012) – commencing at downstream end (CH 00 at Tapleys Hill Road) and increasing upstream. Chainage at Anzac Highway (D/S) is approximately 6689  WorleyParsons (WP) – commencing at CH 00 upstream (approximately Brown Hill Creek Road Mitcham) and increasing downstream. Chainage at Anzac Highway (D/S) 7063. Cross sections and extent of works based on this plan  Civil Surveys and Design (CSD) - commencing at CH 00 upstream (approximately at the Freeway) and increasing downstream. Chainage at Anzac Highway (D/S) 13570. Cost estimates are based on these chainages. The CSD chainages are based on some survey and also reference property boundaries which will be useful long term as a more reliable reference point. They also overcome the possibility of negative chainages. As the AWE chainages increase upstream and the WP and CSD chainages increase downstream there are two points that are identical in both chainage systems and range of points that are similar and may cause confusion if a standard chainage system is not used. These points are around Third Avenue Forestville (AWE/ WP) and Hampton Street Hawthorn (AWE/CSD). The AWE chainages reference existing surveyed cross sections which are used in the WorleyParsons report with updated chainages. The WorleyParsons chainages are used in the modelling and also in preparing extent of upgrades on cross sections for lower brown Hill Creek. There is a risk that the WorleyParsons chainages will be negative if works extend upstream of the CH 00 (Brown Hill Creek Rd Mitcham), although this is not a concern for Lower Brown Hill Creek The WP and CSD chainages can be adjusted as they are a constant distance apart as they both run in the same direction (approximately 6500 metres difference). The CSD chainages have been adopted as they are based on ground survey in Lower Brown Hill Creek will provide the most certainty, have no possibility of negative chainages and referenced to property boundaries.

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Figure 3.1 Chainage Comparison

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3.1.2 Keswick Creek Chainages WorleyParsons have developed chainages along Keswick Creek from a start point upstream near the confluence of Parklands Creek and Glen Osmond Creek and extend downstream past Anzac Highway. Separate chainages for the Le Hunte Street diversion, the Barracks and Anzac Highway diversion have been proposed by Worley Parsons.

3.1.3 Chainage Discrepancies Based on the CSD survey, the length of lower Brown Hill Creek from Anzac Highway to the end of the concrete channel at Watson Street is approximately 3300 metres. The length of the Keswick Creek diversion from Le Hunte Street to Anzac Highway is approximately 2170 metres. There are some variations in segment lengths between the Tonkin Consulting chainages, the AWE chainages and the Worley Parson Chainages. The overall discrepancy is that the Worley Parsons lengths are around 2% less (91 metres). For the purposes of the cost estimate the longer length has been adopted.

3.2 Water and Sewer Services There have been no significant upgrades of water or wastewater services in the study area since previous reports were produced, according to SA Water’s Aquamap database.

3.3 Showgrounds Development It has been confirmed with staff at the Royal Agricultural and Horticultural Society (RAHS) that the development concept plan as previously provided to BHKCSP (confidentially in 2013) has not been updated or revised.

3.4 Workshop and Site Inspection On 7 November 2015 a workshop was facilitated by Tonkin Consulting and attended by representatives of BHKCSP, West Torrens Council, DPTI and Costplan. The purpose of the workshop was to review the LBHC main channel upgrade extent proposed by WorleyParsons as a result of the updated hydraulic modelling. On 8 December 2015, the project team undertook a walkthrough of the LBHC from Anzac Highway to the outfall at the Keswick Creek confluence. The following issues were raised during the workshop and walkthrough:  The current design needs to consider the current LBHC flows as well as the additional flows from Keswick Creek. Based on the WorleyParsons peak 100 year ARI flows (23/12/2015), LBHC will receive 21.6 m3/s additional flow to 46.9 m3/s in a 90 minute storm and an additional 15.5 m3/s increase to 42.2 m3/s in a 36 hour storm . This additional flow and the shorter duration storm will increase peak velocities resulting in increased deterioration of the existing channel sections, and water levels above existing concrete channels with associated erosion potential.  Key design challenge will be the diversion from Keswick Creek to Brown Hill Creek, due to splitting of flows and design of levels (i.e. the Keswick Creek diversion channel at Anzac Highway is lower than LBHC at Anzac Highway)  Some creek banks may need to be upgraded for stability/erosion reasons, rather than for capacity upgrades

Ref No. 20120679-R5B Lower Brown Hill Creek and Keswick Creek Upgrades Concept Report 17

 The section of creek parallel to Daly St will require more efficient design (i.e. concrete channel or culvert) to limit the extent of property acquisition. A potential alternative is to divert some of the flow in a culvert along Garfield Ave, then along the railway corridor back to the creek  The existing concrete channel downstream of South Road is in poor condition and whilst has satisfactory capacity, may require replacement. West Torrens Council is concerned about the structural stability and therefore service life of this section of concrete channel which is within Council’s care and control. This section was not identified as requiring capacity upgrades, but due to the poor condition, and increased peak flows it was agreed that the cost estimate should account for the replacement of this section of channel  The latest hydrological and hydraulic modelling produced by WorleyParsons has not been formally documented. Further explanation is required to fully understand the inputs, objectives and assumptions associated with the results  Most road bridges except Anzac Highway, South Road and Birdwood Terrace require upgrade for capacity reasons. All pedestrian bridges will require widening or adjustment  Approximately 80 metres upstream of South Road there are two large gum trees on opposite sides of the creek which will need to be considered as part of any upgrade  There are many ash trees and other non-native vegetation to be removed, although removal should be managed carefully to prevent bank destabilisation until upgrade works are underway  Between Selby Street and Warwick Street, the creek bank is very close to the northern property boundary. A recent unit development has house footings close to the top of bank with a (poorly constructed) rock wall down to the creek invert  The creek alignment and width is variable and options to partially upgrade segments may be difficult as there will be transition works between segments. For the purposes of the cost estimate, a conservative approach is recommended.

3.5 Concept Design The concept design in Appendix D has been prepared following the workshop and site walk through. The design cross sections are based on the WorleyParsons cross section sketches (20150729 XSect Sketches CH 7063-10335 Anzac-Keswick_Upgrade XS) and (20150118 XSect Sketches Keswick CH11405-1718 Railway-AnzacHwy), modified based on the site walkthrough and workshop. Key changes include:  Chainage 14000 – CH 14260 – West of South Road Whilst the WorleyParsons report does not require upgrade of Lower Brown Hill Creek west of South Road, this section of channel is in poor condition and the water flow level is above the top of concrete lining which is considered to have high potential to erode. A new widened trapezoidal concrete channel is proposed  Chainage 14320 – 14500 – West of Selby Street This section of channel is biased towards the north side of the creek reserve and some realignment will be required to construct a widened creek  Chainage 14500 – 14720 – Grassmere Reserve A high amenity section of creek is proposed although this will need to be developed around the large existing trees. The City of West Torrens would like to investigate a road realignment of Daly Street and the Daly Street bridge  Chainage 14740 – 14960 – Down stream of Daly Street A gabion section is proposed to provide consistent flow cross section from the upstream Grassmere Reserve in place of a concrete trapezoidal channel

Ref No. 20120679-R5B Lower Brown Hill Creek and Keswick Creek Upgrades Concept Report 18

 Chainage 15580 – 16460 – Marion Road to Watson Avenue Concrete channel under care and control of SA Water to be widened. Options include widening on one side, both sides or widen one or both sides with a benched cross section. The City of West Torrens would like to investigate a road realignment at the intersection of Watson Avenue / Beare Avenue including the road bridge  Chainage 16460 – Keswick Creek Concrete channel has sufficient capacity. The concrete channel widens from 1.3 to 2.6 metres for the last 160 metres of channel reflecting the slightly flatter channel grade.

Ref No. 20120679-R5B Lower Brown Hill Creek and Keswick Creek Upgrades Concept Report 19

4 Cost Estimate

4.1 Scope A cost estimate has been prepared by Costplan based on the concept drawings in Appendix D and the walkthrough. The cost estimate report including methodology is included in Appendix E Key risks and accordingly cost contingencies include:  Replacement of road bridges and bridges within the barracks  Culvert transition structures at Le Hunte Street, Keswick Creek at the Barracks, Anzac Highway at Keswick Creek and LBHC  Works through the Royal Adelaide Showgrounds and timing of this work around major events  Culvert/pipe crossing under the railway adjacent Leader Street (multiple passenger rail and freight line)  Availability of access to the creek and manoeuvrability of large equipment within the creek (i.e. cranes delivering and placing culverts)  Requirements for land acquisition, whether it be easements, whole properties, partial properties and ability to sell surplus land.  Extent of upgrade works where an existing section has adequate capacity but is near the end of its useful life  Responsibility to fund and upgrade sections of the culvert under the care and control of SA Water or Commonwealth Government (Army Barracks)  Community consultation and community expectations on the finished product including extent of amenity works such as shared paths, water sensitive design, revegetation etc.  Impact and realignment of underground services, in particular the two DN650 mm water mains and telecommunications cables  Management of base flows and flood flows  Contamination within the worksite. A construction contingency has been added based on the risk of each component. Costs for land acquisitions including easements and disruption costs have been estimated based on a valuation prepared by Maloney Field Services in 2013 with an allowance for escalation to 2016. An allowance for property acquisitions and/or creation of easements has been made in the following locations due to insufficient creek corridor width:  Private property on either the northern or southern side of lower Brown Hill Creek fronting Anzac Highway  Approximately a 10 metre wide strip of land from up to eleven private properties between Daly and Gray Streets  Boundary correction where the creek has encroached into the property at Warwick Avenue  Approximately a 2 metre strip of land from two private properties between Marion Road and Harvey Avenue (the estimate conservatively allows for full acquisition less residual value)  Disruption to properties due to works within existing easements and creation of new easements – downstream side of Harvey Avenue  Other potential boundary corrections between the creek corridor (drainage reserve) and private and state owned properties

Ref No. 20120679-R5B Lower Brown Hill Creek and Keswick Creek Upgrades Concept Report 20

 Property on southern side of Le Hunte Street adjacent Keswick Creek. The properties identified for acquisition and precise land areas need to be confirmed following survey, further investigations and detail design. Most of the land areas involved are part of the existing creek and are of little benefit to the properties concerned. Other land in Government ownership including the Keswick Army Barracks, Adelaide Showgrounds and the rail corridor will be required for the works whilst land adjacent South Road and Herbert Road at Ashford may be required for construction and maintenance access.

Ref No. 20120679-R5B Lower Brown Hill Creek and Keswick Creek Upgrades Concept Report 21

Table 4.1 Cost Estimate – March 2016

Keswick Creek bypass / upgrade

BROWN HILL CREEK Section 1, Section 4, ITEM Section 2 Section 3 Sub Total STORMWATER UPGRADE Le-Hunte - Lower BHC Barracks Anzac Hwy Barracks Design and Documentation, Project 1.1 $2,330,940 $830,222 $1,503,322 $4,203,927 $8,868,411 management etc. 1.2 Services relocations and alterations $573,985 $157,556 $1,503,322 $1,548,815 $3,783,678 1.3 Land Acquisition $350,000 $0 $0 $3,820,000 $4,170,000 TOTAL CLIENTS COSTS $3,254,925 $987,778 $3,006,643 $9,572,742 $16,822,089 2.1 Preliminaries and Onsite Overheads $1,597,078 $511,152 $1,251,837 $1,938,154 $5,298,220 Traffic management and 2.2 $371,807 $114,699 $771,001 $611,794 $1,869,301 environmental requirements 2.3 Contract Direct Costs $11,186,885 $2,989,131 $6,610,679 $17,564,536 $38,351,231 2.4 Contractor Overheads and margin $1,193,855 $323,909 $762,243 $2,011,448 $4,291,456 TOTAL CONTRACTOR COSTS $14,349,625 $3,938,890 $9,395,760 $22,125,933 $49,810,208 1+2 TOTAL WITHOUT RISK $17,604,550 $4,926,668 $12,402,404 $31,698,675 $66,632,297 3 RISK ALLOCATION $4,080,196 $1,115,011 $2,950,269 $7,371,520 $15,516,996 1+2+3 GRAND TOTAL $21,684,746 $6,041,679 $15,352,672 $39,070,196 $82,149,293

SUMMARY NOTES 1 Based on Tonkin drawing set (figures 1-18) issued Dec 2015 2 Costs exclude GST 3 Excludes any escalation, costs based on Q1, 2016 $ 4 3 x 1500 Dia RCP allowed to be micro tunnelled and installed under Rail corridor and Goodwood Road in lieu of open cut RCBC installation 5 Quantities of Lower Brown Hill Creek: creek treatments derived by joint site inspection 6 Council bridge replacements at Daly: Harvey and Watson roads included 7 DPTI bridge replacement at Marion road included 8 Bridge widening at Farnham (allows for the addition of a culvert adjacent to the existing structure) 9 Includes footbridge removal and replacement 10 Costs include an allowance of approx. $1m for the disposal of Low level and Intermediate level contaminated soils 11 Keswick barracks section adopted as 6m base width widened trapezoidal open channel rather than vert sided RC channel 12 Open rectangular channel option used for ANZAC - Farnham section

Ref No. 20120679-R5B Lower Brown Hill Creek and Keswick Creek Upgrades Concept Report 22

5 Recommendation

5.1 Preferred Concept In order to document the proposed upgrade extent, concept design drawings for the entire extended study area have been developed by Tonkin Consulting based on work completed by WorleyParsons and are provided in Appendix D. This design includes:  Le Hunte to the Barracks concept culvert sizes  Brief description of different treatment types for Lower Brown Hill Creek and Keswick Creek in the Barracks  The Keswick Creek to Anzac Highway diversion including upstream and downstream transition structures  Bridge upgrades  Land acquisition.

5.2 Recommendation To progress the concept design to preliminary design suitable for stakeholder and community consultation and more detailed cost estimates, Tonkin Consulting recommends as follows:  If the hydraulic modelling by WorleyParsons is used as the basis for a more detailed level of design by others, the modelling should be peer reviewed, particularly in terms of the methodology and assumptions, in order to minimise potential design interface risk  The preferred concept is suitable for incorporation into the stormwater management plan for the BHKC catchment (i.e. for concept planning purposes)  Detailed survey and services investigations are carried out. Preferably the removal of the ash trees (to stump level) and other non-native vegetation would be undertaken prior to the survey. The survey should include finished floor levels of houses so that a realistic freeboard to houses are provided. This could reduce the extent of works by allowing some flooding of private property in a major event  Boundary survey is undertaken at key areas where encroachments are possible  Key underground services are identified and measured for depth and location as necessary.

Ref No. 20120679-R5B Lower Brown Hill Creek and Keswick Creek Upgrades Concept Report 23

6 References Hydro Tasmania, 2006, Brown Hill and Keswick Creeks Flood Mitigation Study Flood Management Master Plan Tonkin Consulting, 2009, Stage 1 Report - Feasibility & Alignment Selection - Diversions from Keswick Creek to Brown Hill Creek, Adelaide, Reference 20090878RA2C Tonkin Consulting, 2010, Stage 2 Report - Preliminary Design- Diversions from Keswick Creek to Brown Hill Creek, Adelaide, Reference 20090878RA4B WorleyParsons, 2012, Brown Hill Keswick Creek Stormwater Project, Stormwater Management Plan 2012, Adelaide Tonkin Consulting, 2013, Keswick Creek Diversion – Options Report, Adelaide, Reference 20121231FR1B Keswick Creek Bypass (City of West Torrens) Options Report (Tonkin Consulting, 2013) 20120679 FR1C Stage 1 Limited Environmental Site History (Tonkin Consulting 2013) 20121254FR1A Tonkin Consulting, 2013, Lower Brown Hill Creek Channel Upgrade - Channel Assessment - Revised Hydrology, Adelaide, Reference 20130679DR4A Tonkin Consulting, 2013, Lower Brown Hill Creek Channel Upgrade - Stage 1 - Engineering Feasibility Report - Draft, Adelaide, Reference 2012.0679FR2B Tonkin Consulting, 2014, Lower Brown Hill Creek Channel Upgrade - Stage 1 - Engineering Feasibility Report - Interim Report, Adelaide, Reference 2012.0679FR2D Tonkin Consulting, 2015, email 17 July, RE: Diversions modelling by WorleyParsons - Anzac Highway culverts

Ref No. 20120679-R5B Lower Brown Hill Creek and Keswick Creek Upgrades Concept Report 24

Appendix A

Existing Creek Characteristics

Ref No. 20120679-R5B Lower Brown Hill Creek and Keswick Creek Upgrades Concept Report

Segment Invert * Channel Current Manning's Reserve Vegetation Land Care and Segment Location Chainage* Channel Description Grade Planning Zone Length (mAHD) Depth* Capacity* Roughness* Width Description Ownership Custody DS US M DS US m % m3/s m Federal Keswick Creek Government Confluence to Concrete lined channel, 3 m No vegetation SA BH1 16860 16450 410 4.9 6.9 2 0.48 40 0.014 Airport Land Airport (Leased to Watson Ave/ base , 1 in 1.5 batters within creek Water Adelaide Beare Ave Airport Ltd) Watson Ave Vehicle bridge over concrete Airport/ SA BH2 16450 16440 10 6.9 7.1 2 5.00 20 0.014 N/A N/A CWT Bridge lined channel Residential Water Some trees Watson Ave to Concrete lined channel, 2m Residential/Small SA BH3 16440 16035 405 7.1 9 2 0.48 20 0.014 10m overhanging CWT Harvey Ave wide base, 1:1.1 batters Section Private Water channel Vehicle bridge over concrete SA BH4 Harvey Ave Bridge 16035 16025 10 9.1 9.2 2.1 1.67 25 0.014 N/A N/A Residential CWT lined channel Water

Segment Location Chainage* Segment Invert * Channel Description Channel Grade Current Manning's Reserve Width Vegetation Description Planning Land Care and Length (mAHD) Depth* Capacity* Roughness* Zone Ownership Custody DS US m DS US m % m3/s m

Concrete-lined channel, NE side lined with pine BH5 Parallel to Debra Ct 16025 15865 160 9.2 9.9 2 0.44 25 0.014 10 Residential CWT SA Water 1.8m wide base, 1:1 batters trees.

Some vegetation on Debra Ct to Marion Concrete-lined channel, BH6 15865 15760 105 9.9 10.2 2.3 0.30 35 0.014 10 northern side of Residential CWT SA Water Rd 1.8m wide base, 1:1 batters channel. Vehicle bridge over BH7 Marion Rd Bridge 15760 15740 20 10.2 10.4 1.7 2.50 15 0.014 N/A N/A Residential CWT DPTI concrete lined channel Minimal within Concrete Channel US Concrete-lined channel, BH8 15740 15575 165 10.4 11.1 2 0.42 15 0.014 12m channel reserve, some Residential CWT SA Water of Marion Rd 1.9m wide base, 1:1 batters overhanging trees. Rock-lined base 3.2m wide, End of Concrete to 0.045 base, BH9 15575 15415 160 11.1 11.6 1:1 earth/rock/retaining 2.2 0.31 20 12m Some smaller trees Residential CWT CWT Packard St 0.07 sides wall batters Pedestrian bridge over 0.045 base, BH10 Packard St Bridge 15415 15413 2 11.6 11.6 2.1 0.00 15 N/A N/A Residential CWT CWT earth/rock channel 0.08 sides

Segment Location Chainage* Segment Invert * Channel Description Channel Grade Current Manning's Reserve Vegetation Description Planning Land Care and Length (mAHD) Depth* Capacity* Roughness* Width Zone Ownership Custody DS US m DS US m % m3/s m

Packard St to Rock-lined base 1.6m wide, 0.045 base, 2 significant trees. Some BH11 15413 15200 213 11.6 12.8 2.5 0.56 15 12m Residential CWT CWT Birdwood Tce 1:2.5 earth/rock batters 0.08 sides areas of dense vegetation.

2 x 3.6m wide x 2.22m high BH12 Birdwood Tce Bridge 15200 15180 20 12.8 12.9 - 0.53 30 0.014 N/A N/A Residential CWT CWT culverts Birdwood Tce to Rock-lined base 5m wide, 0.045 base, Some areas of dense BH13 15180 15005 175 13.1 13.9 3 0.45 35 12.5m Residential CWT CWT Gray St 1:2 earth/rock batters 0.06 sides vegetation. Pedestrian bridge over 0.045 base, BH14 Gray St Bridge 15005 15000 5 13.9 14 3 2.00 40 N/A N/A Residential CWT CWT earth/rock channel 0.06 sides Gray St to Private Rock-lined base 2m wide, 0.045 base, BH15 15000 14940 60 14 13.8 3.5 -0.35 25 12 Moderately vegetated Residential CWT CWT Property 1:1 earth batters 0.12 sides Parallel to Daly St Rock-lined base 2.5m wide, Moderately vegetated BH16 14940 14860 80 13.8 14.45 3 0.81 20 0.06 0 Residential CWT CWT (Private Property) 1:0.6 earth batters (exotic), 3 significant trees

Segment Location Chainage* Segment Invert * Channel Description Channel Grade Current Manning's Reserve Vegetation Description Planning Land Care and Length (mAHD) Depth* Capacity* Roughness* Width Zone Ownership Custody DS US m DS US m % m3/s m

12.5 East- Private Property to Rock-lined base 2m wide, 0.045 base, West Section, Private BH17 14860 14740 120 14.45 15.4 3 0.88 20 Vegetation on banks Residential CWT Daly St 1:1.5 earth/rock batters 0.08 sides 28 North- (Various) South Section Corrugated domed tunnel 0.045 base, BH18 Daly St Bridge 14740 14730 10 15.4 15.5 - 1.00 20 N/A N/A Residential CWT CWT 2.3m high 3.7m wide 0.08 sides 10 significant trees. 4.5m wide earth/ rock-lined 34m 0.045 base, Heavily vegetated in BH19 Grassmere Reserve 14730 14500 230 15.5 16.7 base width, 1:2.5 earth 3 0.53 15 (excluding Residential CWT CWT 0.06 sides channel and Council batters road reserve) reserve. Pedestrian bridge over 0.045 base, BH20 Warwick Ave Bridge 14500 14495 5 16.7 16.7 2.8 0.00 35 N/A N/A Residential CWT CWT earth/rock channel 0.06 sides 1 significant tree. Areas Warwick Ave to Rock-lined base 3.5m wide, 0.045 base, BH21 14495 14220 275 16.7 18.1 3.3 0.50 20 12 of dense vegetation on Residential CWT CWT Concrete Lining 1:1.5 earth/rock batters 0.08 sides creek banks. Start of Concrete to Concrete/rock base 1m 0.02 base, Some vegetation in BH22 14220 14140 80 18.1 18 4.3 -0.13 >40 12 Residential CWT CWT Beauchamp St wide, 1:1 concrete batters 0.018 sides creek reserve

Segment Location Chainage* Segment Invert * Channel Description Channel Grade Current Manning's Reserve Width Vegetation Description Planning Land Care and Length (mAHD) Depth* Capacity* Roughness* Zone Ownership Custody DS US m DS US m % m3/s m

Pedestrian bridge over Beauchamp St 0.02 base, BH23 14140 14138 2 18 18 concrete channel, some local Unknown 0.00 N/A N/A N/A Residential CWT CWT Footbridge 0.018 sides rocks Beauchamp St Concrete/rock base 1m 0.02 base, BH24 14138 14000 138 18 20.8 3.2 3.73 40 12 Sparse vegetation Residential CWT CWT to South Rd wide, 1:1.5 concrete batters 0.018 sides South Rd 2 x 4.2m wide x 2.44m high BH25 14000 13945 55 20.8 21.1 - 0.56 40 0.015 12 N/A Residential CWT DPTI Bridge culverts 5 significant trees. 3.5m wide earth base, South Rd to 0.045 base, Relatively dense BH26 13945 13700 245 21.1 22.6 mostly 1:1 earth batters. 2.9 0.51 25 12 Residential CWT CWT Farnham Rd 0.08 sides vegetation, some large Some retaining walls. trees rooted in banks. Farnham Rd 4.6m wide x 2.53 high 0.045 base, BH27 13700 13690 10 22.6 22.8 - 5.00 25 N/A N/A Residential CWT CWT Bridge culvert 0.08 sides 4m wide earth/rock channel, 12 (except short Relatively dense Farnham Rd 0.045 base, BH28 13690 13550 140 22.8 23.2 1:0.7 batters. Some retaining 2.6 0.29 20 wider section vegetation, some large Residential CWT CWT to Anzac Hwy 0.08 sides walls. adj Farnham Rd) trees rooted in banks.

Segment Invert * Channel Current Reserve Chainage* Grade Manning's Vegetation Care and Segment Location Length (mAHD) Channel Description Depth* Capacity* Width Planning Zone Land Ownership Roughness* Description Custody DS US m DS US m % m3/s m Barracks Concrete-lined channel 1.5m base width, Federal Federal K1 1745 1640 105 23 24.9 3.6 2.1 20 0.013 N/A None Excluded Channel DS 3:2 batters. Government Government

Concrete-lined channel, 2.5m base width, Barracks Federal Federal K2 1640 1310 330 24.9 26.6 1:1 batters (becoming vertical sides at 2 0.5 20 0.013 N/A None Excluded Channel US Government Government railway). Span includes 4 private bridges.

Keswick Rail Rectangular concrete open channel, 4m Excluded/ K3 1310 1280 30 26.6 26.7 3 0.3 30 0.015 N/A None DPTI/ARTC DPTI Corridor wide base overlaid with rail bridge. Showgrounds

Segment Invert * Channel Current Reserve Chainage* Grade Manning's Vegetation Care and Segment Location Length (mAHD) Channel Description Depth* Capacity* Width Planning Zone Land Ownership Roughness* Description Custody DS US m DS US m % m3/s m State Showgrounds 2x3.2mx1.8m box K4 1280 1275 5 26.7 Unknown N/A Unknown 25 0.015 N/A N/A Showgrounds Government TBC Shared Path culverts (brick walls) (Leased to RAHS) State 2x3.0mx1.6m box K5 Showgrounds 1275 800 475 Unknown Unknown N/A Unknown 25 0.015 N/A N/A Showgrounds Government TBC culverts (brick walls)† (Leased to RAHS)

2x2.4mx1.6m box Showgrounds/ K6 Goodwood Road 800 780 20 Unknown 29.6 N/A Unknown 25 0.015 N/A N/A City of Unley DPTI culverts† Mixed Use 2

†Information provided by RAHS

Segment Invert * Channel Current Reserve Chainage* Grade Manning's Vegetation Care and Segment Location Length (mAHD) Channel Description Depth* Capacity* Width Planning Zone Land Ownership Roughness* Description Custody DS US m DS US m % m3/s m Overhanging Goodwood Road 3.7m wide concrete base, vertical (at vegetation 0.015 base, K7 to Wayville 780 655 125 29.6 29.8 Goodwood Rd) to 1:1 concrete 2.3 0.2 25 N/A on channel Mixed Use 2 Private TBC 0.02 sides Reserve batters with overgrown vegetation banks and batters. 4 3.4m wide concrete base, 1:0.5 Banks quite 0.015 base, (upstream RB300 K8 Wayville Reserve 655 525 130 29.8 30.2 concrete batters. Includes pedestrian 2.2 0.3 35 densely City of Unley City of Unley 0.02 sides of main (Residential) bridge (not in HECRAS). vegetated. reserve) Banks quite Wayville Reserve 3.4m wide concrete base, 1:0.5 0.015 base, RB3000 K9 525 470 55 30.2 30.3 2.2 0.2 15 N/A densely Private TBC to Joslin St concrete batters 0.02 sides (Residential) vegetated. RB3000 K10 Joslin St Bridge 470 450 20 30.3 30.4 4.9m wide x 1.5m high box culvert N/A 0.5 20 0.015 N/A N/A City of Unley City of Unley (Residential) Banks Joslin St to Le 3m wide concrete base, near vertical RB300 Private/City of K11 450 300 150 30.4 30.9 2.3 0.3 15 0.015 9 moderately City of Unley Hunte St concrete sides (Residential) Unley vegetated.

Appendix B

Photos – Creek walkthrough December 2015

Ref No. 20120679-R5B Lower Brown Hill Creek and Keswick Creek Upgrades Concept Report

Chainage 13540: ANZAC Highway culvert, Chainage 13540: Typical creek section south of facing upstream ANZAC Highway, facing downstream

Chainage 13700: Farnham Road culvert, Chainage 13750: Typical creek section facing downstream downstream of Farnham Road, facing downstream

Chainage 13850: Gabions placed to prevent eroding of the bank at bend 100 metres upstream of South Road and large native tree, facing upstream Chainage 13860: Large native tree on the south bank 100 metres upstream of South Road

Ref No. 20120679-R5B – Appendix B 1

Chainage: 13950: South Road culvert with gabions and permeable concrete mass block on the banks in the 50 metres approaching the culvert, facing downstream. 600 mm rock in base to limit erosion

Chainage 14020: Concrete channel and large native tree just downstream of South Road, facing downstream

Chainage 14060: Damage to the concrete Chainage 14100: Further damage to the channel, consistent along the length of the concrete channel. 75 mm thick lightly channel in the straight downstream of South reinforced concrete. Large void behind wall Road

Ref No. 20120679-R5B – Appendix B 2

Chainage 14130: Beauchamp Street Chainage 14250: Sediment and rubbish pedestrian bridge, facing upstream deposit near the end of the concrete channel downstream of the Beauchamp Street pedestrian bridge, facing downstream

Chainage 14310: Possible vehicle entry Chainage 14380: Loose concrete brick point from Selby Street on the north bank, retaining wall midway between Selby Street facing downstream and Warwick Avenue

Ref No. 20120679-R5B – Appendix B 3

Chainage 14410: Recently installed rock retaining wall on the north bank, midway between Selby Street and Warwick Avenue, facing downstream Chainage 14390: Large native tree on the south bank midway between Selby Street and Warwick Avenue, facing downstream

Chainage 14410: Building foundations 6‐7 Chainage 14480: Typical creek section metres from the centre of the creek, upstream of Warwick Avenue, facing midway between Selby Street and Warwick downstream Avenue, facing downstream

Ref No. 20120679-R5B – Appendix B 4

Chainage 14490: Warwick Avenue pedestrian Chainage: 14740: Daly Street culvert, facing bridge, facing upstream downstream

Chainage 14750: Possible vehicle entry point Chainage 14770: Site of creek realignment from Daly Street on the south bank, facing 20 metres downstream of Daly Street on upstream the south bank, facing downstream

Chainage 14940: Site of creek realignment Chainage 14900: Damaged concrete embankment in the straight between the 60 metres upstream of Gray Street on the two creek realignments, facing downstream north bank, facing upstream. Council has recently purchased this property

Ref No. 20120679-R5B – Appendix B 5

Chainage 14980: Existing concrete bank in Chainage 15010: Gray Street pedestrian the straight upstream of Gray Street on the bridge, facing upstream south bank, facing downstream

Chainage 15070: Recently constructed Chainage 15170: Birdwood Terrace culvert gabions downstream of Gray Street, the and heritage concrete retaining wall, facing gabions have been undermined by erosion, downstream facing downstream

Chainage 15170: General creek section Chainage 15320: General creek section upstream of Birdwood Terrace, facing between Birdwood Terrace and Packard upstream Street, facing downstream

Ref No. 20120679-R5B – Appendix B 6

Chainage 15410: Possible vehicle entry Chainage 15410: Packard Street pedestrian point from Packard Street on the north crossing, facing downstream bank, facing downstream

Chainage 15410: Service pipe crossing the Chainage 15420: Culverts and permeable river at Packard Street, facing upstream concrete mass blocks lining the banks just downstream of Packard Street, facing downstream

Chainage 15570: Sediment trap prior to Chainage 15580: Concrete channel concrete channel beginning just upstream of beginning just upstream of Wyatt Street, Wyatt Street, facing downstream facing downstream

Ref No. 20120679-R5B – Appendix B 7

Chainage 15610: Marion Road culvert, Chainage 15830: Damage to the concrete facing downstream channel at the curve after Marion Road, facing upstream

Chainage 15870: Large native trees on the south bank just downstream of the curve

following Marion Road, facing downstream

Chainage 15870: Large native tree on the north bank just downstream of the curve

following Marion Road, facing downstream

Ref No. 20120679-R5B – Appendix B 8

Chainage 15910: Trees that may be Chainage 16020: Harvey Avenue culvert, removed with council approval on both facing downstream sides of the bank running parallel to

Fletcher Street, facing downstream

Chainage 16450: Watson Avenue culvert Chainage 16540: Damage to the concrete with low service pipes crossing the channel, channel running parallel to Watson Avenue facing upstream

Chainage 16580: Flow reading apparatus? Chainage 16860: Confluence of Brown Hill

Running parallel to Watson Avenue and Keswick Creeks, facing downstream

Ref No. 20120679-R5B – Appendix B 9

Appendix C

Recommended design flow rates (Scenario #31, December 2015)

Ref No. 20120679-R5B Lower Brown Hill Creek and Keswick Creek Upgrades Concept Report FIGURE 6.1 Keswick Creek Additional Inflow at DRAFT Keswick Creek 90 minute – 20.2 m3/s Goodwood Road 3 3 90 minute – 11.2 m /s 6 hour – 15.4 m3/s 90 minute – 9.3 m /s

3 3 6 hour – _5.9 m3/s 6 hour – 7.7 m /s 36 hour – 12.6 m /s 36 hour – 5.8 m3/s 36 hour – _2.5 m3/s Keswick Creek

90 minute – 31.3 m3/s

6 hour – 24.6 m3/s

3 36 hour – 20.5 m /s

Anzac North Diversion

3 90 minute – 10.7 m /s 3 6 hour – 9.0 m /s 36 hour – 7.7 m3/s Keswick Creek

3 Anzac South Diversion Le Hunte Diversion 90 minute – 25.5 m /s

3 3 90 minute – 10.9 m3/s 90 minute – 11.7 m /s 6 hour – 21.2 m /s 3 3 6 hour – 9.3 m3/s 36 hour – 18.4 m /s 6 hour – 9.1 m /s 36 hour - 7.8 m3/s 36 hour – 8.0 m3/s

Additional Inflow at Anzac Highway

90 minute – 5.8 m3/s 3 6 hour – 4.4 m /s 36 hour –_2.4 m3/s

Brown Hill Creek Brown Hill Creek 3 3 90 minute – 20.8 m /s Note 90 minute – 46.9 m /s The results of the modelling demonstrate that the 90 minute is 3 6 hour – 37.6 m3/s 6 hour – 16.6 m /s the critical storm for all sections of the Brown Hill – Keswick

3 Creek system, with the exception of Brown Hill Creek 36 hour – 42.2 m3/s 36 hour – 30.3 m /s upstream of Anzac Highway, where the 36 hour storm is critical. The Peak flow is highlighted for each case.

PEAK 100 YEAR ARI FLOWS FOR MITIGATION SCENARIO FOR 90 MINUTE, 6 HOUR AND 36 HOUR STORMS BHCK Stormwater Management Plan fg02356arm151219 - Figure 1 MItigation #31 Flows_v2.doc [23-12-2015]

Appendix D

Concept Design Drawings

Ref No. 20120679-R5B Lower Brown Hill Creek and Keswick Creek Upgrades Concept Report

BROWNHILL CREEK BROWNHILL KESWICK CREEK KESWICK

WATSON AVE

16861

16500 AVE BEARE FLETCHER ST FLETCHER

LOWER BROWN HILL CREEK AND KESWICK UPGRADES 16000 CRT DEBRA

BROWN HILL KESWICK CREEK STORMWATER PROJECT MARION ROAD MARION

BROWNHILL CREEK 15500

BIRDWOOD TCE

15000 DALY ST DALY

14500

14000 RD SOUTH KESWICK CREEK KESWICK

13500

ANZAC

BROWNHILL CREEK HIGHWAY

K2000

K1500 RAIL

SHOWGROUNDS

ADELAIDE

ROYAL

K1000 GOODWOOD RD GOODWOOD LOCATION PLAN

KESWICK CREEK

K500 FIGURE 1 K280 16863.93 4.24 16860 4.90

16860 16840 4.97

16840

CHANNEL BASE WIDTH WIDENS TO 2.4m 16820 5.06

16820 16800 5.12 LOWER BROWN HILL CREEK AND KESWICK UPGRADES

16800 16780 5.21 BROWN HILL KESWICK CREEK STORMWATER PROJECT 16780 16760 5.26

16760 16740 5.32

16740 RETAIN AS IS 16720 5.38 16720 16700 5.47 16700

16680 5.56 SURVEY JUNE 2015 16680 16660 5.72 16660 16640 5.83 16640 16620 5.96 16620 16600 6.08 16600 16580 6.21 16580 16560 6.32 16560 16540 6.46 WATSON AVE 16540

16520 6.56 16520

16500 6.70 16500 16480

16480 6.83

16460 1) SECTION (REFER PLAN AND LONG SECTION

ANSETT AVE

REALIGNMENT 16460 6.90

16440 ROAD POSSIBLE

10m SPAN, 10m WIDE 10m SPAN, 10m ROAD BRIDGE UPGRADE BRIDGE ROAD

16420 16440 7.04

16400 AVE BEARE

2a, 2b, 2c 2b, 2a,

SECTIONS 16420 7.20 16380 REFER

16360 16400 7.31 DATUM R.L. = 2.000 INVERT LEVEL CHAINAGE

FIGURE 2 16340

16320

16300

16280 16400 16400 7.31 ANSETT AVE 16380 16380 7.44

16360 16360 7.56

16340 16340 7.68

LOWER BROWN HILL CREEK AND KESWICK UPGRADES 16320 16320 7.79

16300 16300 7.91 BROWN HILL KESWICK CREEK STORMWATER PROJECT

16280 16280 8.04

16260 CREEK RESERVE NARROWS TO 10m APPROX 16260 8.15 (REFER SECTION 2a, 2b, 2c) 16240 16240 8.24

16220 16220 8.38

16200 16200 8.43 SURVEY JUNE 2015

16180 16180 8.48

16160 16160 8.56

16140 16140 8.65 BELTRAME CRT BELTRAME 16120 8.74 16120

16100 8.83 16100 OR BOX CULVERT UNDER DRIVEWAY

POSSIBLE BRIDGE EXTENSION 16080 8.91 16080 EXISTING EASEMENT HARVEY AVE 16060 8.99 16060 16040 9.07 10m SPAN, WIDE 16040 BRIDGE UPGRADE

ROAD 16020 9.15 16020 16000 9.26 16000 15980 9.33 15980 15960 9.43 15960

(WIDEN 1 SIDE ONLY AS CREEK DEBRA CRT DEBRA (REFER SECTION 2b)

BIASED SOUTH SIDE) 15940 9.50 SUBJECT TO COUNCIL APPROVAL SELECT TREES TO BE REMOVED 15940 15920 9.54

PLAN AND LONG SECTION 15920 15900 9.69 15900

15880 9.75 15880

15860 9.83 15860 RETAINED IF POSSIBLE LARGE GUMS TO BE 15840 9.92

15840 15820 10.03 FIGURE 3 15800 10.11 15820 DATUM R.L. = 5.000 INVERT LEVEL CHAINAGE

15800

15780

15760 (REFER SECTION 2b) 15800 10.11 CHANNEL UNDER CARE AND CONTROL OF SAWATER CH15580 TO KESWICK CREEK CH16860 CONCRETE NOTE: 15800 15780 10.20 UPGRADE 8m SPAN 20m MARION ROAD BRIDGE PRIVATE PROPERTY SIGNIFICANT GUM TREE ON 15760 10.25 15780 EXISTING SEDIMENT TRAP PRIOR TO CONCRETE CHANNEL 15740 10.38

15760 MARION ROAD MARION 15720 10.41 15740 LOWER BROWN HILL CREEK AND KESWICK UPGRADES 15700 10.49 15720 AT MARION ROAD TO SECTION 3 (REFER SECTION 2a,2b,2c TRANSITION STRUCTURE 15680 10.57 BROWN HILL KESWICK CREEK STORMWATER PROJECT

15700 OVER 20m) 15660 10.66 15680 15640 10.74 15660 15620 10.83 15640

15600 10.91 WYATT ST 15620WYATT 15580 10.98

15600 15560 11.24 SURVEY JUNE 2015

15580 15540 11.35

15560 TRANSITION TO CONCRETE KIETH AVE KIETH

CHANNEL OVER 20m 15520 11.32 DUDLEY AVE DUDLEY

SECTION 4

DAVIES ST DAVIES 15500 11.38 EDWARD 15540

15520 15480 11.35

15500 15460 11.52

15480 15440 11.74 PEDESTRIAN BRIDGE

15460 12m SPAN 15420 11.53

15440 15400 11.36

15420 15380 11.49

15411 ST PACKARD 15360 11.48 15400

15340 11.59 15380 MINOR REGRADING

15320 11.53

15360 (REFER SECTION 5)

15300 11.72 15340 PLAN AND LONG SECTION

15280 12.00 15320 15260 12.24 15300 15240 12.55 15280 15220 12.69 15260

15200 12.97 DATUM R.L. = 8.000 INVERT LEVEL BIRDWOOD TCE CHAINAGE FIGURE 4 15240

McARTHUR 15220 AVE 15200 TO BE RETAINED ROAD BRIDGE 15200 12.97

15180 12.91

15160 13.18 SURVEY JUNE 2015

15140 13.08 ALLOW 80% OF LENGTH (EACH SIDE) WITH GABIONS TO

STABILISE WALLS AS PER SECTION 4 15120 13.04 NEW ROCK INVERT LOWER BROWN HILL CREEK AND KESWICK UPGRADES 15100 13.00 15200 RETAIN 15080 13.05

BROWN HILL KESWICK CREEK STORMWATER PROJECT 15180 15060 13.13 15160 15040 13.03 15140 BIRDWOOD TERRACE 15020 13.41

15120 PEDESTRIAN BRIDGE GRAY STREET 15000 13.69 15100

14980 13.61

TILDEN AVE TILDEN 15080 MC ARTHUR AVENUE 14960 13.66 15060 REINFORCED CONCRETE WALL OUTSIDE OF BENDS CH 14920-14960 (40m) 14760-14840 (80m). 14940 13.89 15040

POSSIBLE LAND ACQUISITION SO CREEK IN COUNCIL OWNERSHIP. 14920 13.79 15020 (SECTION 4) SOME MINOR CREEK REALIGNMENT

GRAY ST GRAY 14900 14.29 15000 PROVIDE NEW FENCES. 14880 14.56 14980 MINOR REGRADING

14860 14.39 14960

14840 14.62

14820 14.94

14940

14900

14920 14880 14860 14820

14840 14760 14800 14.97

14740 14780 15.10 DALY ST DALY POSSIBLE ROAD REALIGNMENT CREEK REALIGNMENT 14720 14760 15.04 BRIDGE UPGRADE

14700 7m SPAN ROAD 14740 15.38

14680

14720 15.39 CROSS TCE CROSS 14660 GRASSMERE RESERVE - HIGH AMENITY WORKS 14700 15.67

PLAN AND LONG SECTION GARFIELD AVE GARFIELD

14640 (REFER SECTION 6) 14680 15.92

14620 14660 15.83

14600 14640 15.82

14620 15.97

14600 16.01 DATUM R.L. = 11.000 CHAINAGE INVERT LEVEL FIGURE 5 14600 16.01

14580 16.31

(SECTION 6) 14560 16.26

14600 14540 16.45

14580 14520 16.58

14560 PEDESTRIAN BRIDGE WARWICK AVENUE

LOWER BROWN HILL CREEK AND KESWICK UPGRADES 14500 16.51 14540 14520 14480 16.64 14500 SURVEY JUNE 2015 BROWN HILL KESWICK CREEK STORMWATER PROJECT

14480 AVE WARWICK 14460 16.75 ALLOW 60% LENGTH (EACH SIDE) GABION BANK STABILISATION. NEW ROCK RETAINING WALL SOME REALIGNMENT MAY BE REQUIRED TO AVOID 14440 16.80 14460 ENCROACHMENT ENCROACHMENT ON NORTHERN SIDE

14420 16.96 NEW ROCK INVERT. 14440 RETAIN 14420 14400 17.11

14400 14380 17.39

14380 14360 17.48 SIGNIFICANT GUM 14360 14340 17.49 SELBY STREET 14340 14320 17.60

14320 SELBY ST SELBY

14300 17.89 SEDIMENT DEPOSIT 14300

14280 17.92 14280

14260 17.82

BASNETT ST BASNETT 14260

14240 14240 18.08

14220

GARFIELD AVE GARFIELD 14220 18.00

14200 TRANSITION TO EXISTING CHANNEL OVER 50m SELBY STREET. NEW CONCRETE TRAPEZOIDAL CHANNEL (REFER SECTION 7) 14200 17.88

14180 MATCH TO SOUTH ROAD CULVERT OUTLET 14180 17.84

14160 BEAUCHAMP STREET PEDESTRIAN BRIDGE 14160 17.95

14140 ST BEAUCHAMP EXISTING POOR CONDITION CONCRETE CHANNEL. 14140 18.04 14120 LIFT INVERT TO REDUCE DEPTH

14100 14120 18.20

14080 14100 18.46 PLAN AND LONG SECTION 14060 14080 18.75

14040 14060 19.14

14020

SIGNIFICANT TREE 14040 19.47 14000 14020 19.88 SOUTH ROAD CULVERT

TO BE RETAINED 14000 20.78 DATUM R.L. = 14.000 CHAINAGE INVERT LEVEL FIGURE 6 14000 20.78 CULVERT TO BE RETAINED EXISTING SOUTH ROAD

13980 20.94

13960 21.08

13940 21.03

13920 20.98 LOWER BROWN HILL CREEK AND KESWICK UPGRADES 14000 13900 21.17

13980

BROWN HILL KESWICK CREEK STORMWATER PROJECT SOUTH RD SOUTH 13880 21.34

13960 CH13840 - 13880 (40m) CONCRETE WALL OUTSIDE OF BEND

13860 21.29 13940 DESIGN TO AVOID SIGNIFICANT TREES

13840 21.70

13920 (SECTION 5) SURVEY JUNE 2015

13900 13820 21.57

1388013840 LARGE GUM TREES

13800 21.74 HERBERT RD HERBERT 13820 13800 13780 22.01

13780 13760 22.19

TYSON ST TYSON 13760 13740 22.18 13740

13720 13720 22.62 FARNHAM ROAD CULVERT EXISTING 4.6W x 2.4H TO BE REPLACED

FARNHAM RD FARNHAM 13700 13700 22.90 OF NEW CULVERT. POSSIBLE CULVERT ADJACENT WITH LOWER INVERT. 13680

13680 22.81 NOTE: FARNHAM ROAD CULVERT INVERT 22.9 IS ABOVE

HERITAGE STUMP TO REMAIN 13660 13660 22.93 13640 NEW BOX CULVERTS FROM KESWICK CREEK AND ANZAC HIGHWAY

(REFER SECTION 7) 13640 23.27 13620 13600 K2477 13620 23.16 K2477

13600 23.40 REFER ENLARGEMENT FIGURE 11

PLAN AND LONG SECTION SYME ST SYME 13580 23.62 INV 22.64

13560 23.44 ANZAC HIGHWAY CULVERT EXISTING BROWN HILL CREEK KESWICK CREEK DIVERSION EXISTING 3.9W x 2.4H K2400 TO BE RETAINED

K2400 13540

13520

13501.96 FIGURE 7 CHAINAGE

K2300 DATUM R.L. = 19.000 INVERT LEVEL

K2300 13640

13600 13620

K2477

K2477 LOWER BROWN HILL CREEK AND KESWICK UPGRADES

K2400K2400 BROWN HILL KESWICK CREEK STORMWATER PROJECT

REFER ENLARGEMENT FIGURE 11 SYME ST SYME

K2300K2300

ANZAC HIGHWAY LEADER ST LEADER

K2200K2200

2x3.6 x1.5 RCBC

K2100K2100

Ø650 WATERMAIN TO BE LOWERED

REFER ENLARGEMENT FIGURE 11 PLAN AND LONG SECTION

K2000K2000

K1900 K1900 EXISTING KESWICK CREEK

REFER SECTION 10 FIGURE 8 CONCRETE CHANNEL. REFER SECTION 10. RECTANGULAR 7.5m WIDE

K1800K1800

MAPLE AVENUE MAPLE

BARRACKS KESWICK LOWER BROWN HILL CREEK AND KESWICK UPGRADES BROWN HILL KESWICK CREEK STORMWATER PROJECT 6.3m WIDE RECTANGULAR CONCRETE CHANNEL

K1700K1700

WIDEN EXISTING CONCRETE CHANNEL REFER SECTION 9.

REFER ENLARGEMENT FIGURE 11 K1600K1600

K1500

K1400

K1400

RAILWAY

AND FREIGHT LINES)

CULVERTS UNDER

RAIL (PASSENGER

K1300K1300

K1200K1200

NEW 3.3x1.5 RCBC

PLAN AND LONG SECTION

SHOWGROUNDS

ADELAIDE ROYAL

K1100K1100 FIGURE 9

K1000 K900

K900 K1000 Ø650 WATERMAIN TO BE LOWERED

K800K800 GOODWOOD RD GOODWOOD LOWER BROWN HILL CREEK AND KESWICK UPGRADES BROWN HILL KESWICK CREEK STORMWATER PROJECT

K700K700

LE HUNTE ST

NEW 3.3x1.5 RCBC

K600K600 RHYL AVE RHYL

K500K500 JOSLIN ST JOSLIN

REFER ENLARGEMENT FIGURE 11

K400 K400 CREEK KESWICK PLAN AND LONG SECTION

K300 K300

K280

K280

TRAMWAY FIGURE 10 ENLARGEMENT 1 - ANZAC HIGHWAY/BROWN HILL CREEK

NEW OPEN CHANNEL LOWER BROWN HILL CREEK AND KESWICK UPGRADES

ANZAC HIGHWAY

ENLARGEMENT 3 - KESWICK

BROWN HILL KESWICK CREEK STORMWATER PROJECT

RCBC K1500 EXISTING

CREEK/RAILWAY EXISTING CHANNEL EXISTING

NEW RCBC 3.3 x 1.5m

2x3.6x1.5 RCBC ANZAC

EXISTING 2x3.2x1.8

BRICK CULVERT HIGHWAY

RAILWAY

K2400 ENLARGEMENT 4 - KESWICK CREEK/LEHUNTE STREET ENLARGEMENT 2 - ANZAC HIGHWAY/KESWICK CREEK

LE HUNTE

STREET

RCBC NEW 3.3x1.5 CREEK

KESWICK ANZAC HIGHWAY

RCBC

2 x 3.6 x 1.5 EXISTING KESWICK CREEK KESWICK EXISTING K300 PLAN AND LONG SECTION

EXISTING CULVERT

TO BE DIVERTED

K280

LOWER Ø650

WATERMAIN KESWICK CREEK KESWICK

BARRACKS

KESWICK FIGURE 11 9.00 1.00

1 1 2.00 8.00 1 1 1.00 1.00 3.00 1.00 1.00 2.50 TYPICAL SECTION 1 1.00 1.00 CONCRETE LINED CHANNEL 7.50 - 2.00 1.00

2.00 6.00 7.00 TYPICAL SECTION 9 1 1 1 1 TYPICAL SECTION 5 TYPICAL SECTION 4 (CH K1550-K1800) - - GABION CHANNEL, - GABION CHANNEL, CONCRETE LINED ROCK LINED BASE ROCK LINED BASE RECTANGULAR CHANNEL 5.00

TYPICAL SECTION 2A 1 CONCRETE LINED CHANNEL 1 5 1 - 5 5 1.00 1.00 1.50 2.00

5.00

1 2.00 6.30 1 TYPICAL SECTION 6 TYPICAL SECTION 6 - LANDSCAPED CHANNEL, - ALTERNATE NATURAL ROCK TYPICAL SECTION 10 5.00 ROCK LINED BASE (CH K1800-K1950) -

TYPICAL SECTION 2B 9.00 CONCRETE LINED RECTANGULAR CHANNEL - CONCRETE LINED CHANNEL

1 1 9.0 1 1 NOTE: 3.00 3.00 1. TYPICAL CROSS SECTIONS BASED ON MODEL AND PLANS 1 1

1.00 PROVIDED BY WORLEYPARSONS BASED ON PEAK FLOWS 1 1 SCENARIO #30 6/10/2015

1.00 2. ROCK BASE 300mm THICK OF Ø200-Ø400mm ROCK. 3. CONCRETE WALLS - 300mm THICK STEEL REINFORCED. 2.00 EXIST TYPICAL SECTION 7 4. ASH TREES TO BE REMOVED. TYPICAL SECTION 2C - CONCRETE LINED CHANNEL - CONCRETE LINED CHANNEL 3.90 1 1 1 1 3.60 3.00 7.00 2.00 3.00 2.40

6.50 1.50

TYPICAL SECTION 3 TYPICAL SECTION 8 NOTE: TYPICAL SECTION 8 CULVERT DIMENSIONS - CONCRETE LINED CHANNEL - BOX CHANNEL ARE INTERNAL - CONCRETE LINED CHANNEL (ALTERNATIVE)

BROWN HILL KESWICK CREEK STORMWATER PROJECT TYPICAL SECTIONS LOWER BROWN HILL CREEK AND KESWICK CREEK UPGRADES FIGURE 12 BROWN HILL KESWICK CREEK STORMWATER PROJECT SECTIONS LOWER BROWN HILL CREEK AND KESWICK CREEK UPGRADES FIGURE 13 CH 14590

BROWN HILL KESWICK CREEK STORMWATER PROJECT SECTIONS LOWER BROWN HILL CREEK AND KESWICK CREEK UPGRADES FIGURE 14 CH 14241 CH 14215

BROWN HILL KESWICK CREEK STORMWATER PROJECT TYPICAL SECTIONS LOWER BROWN HILL CREEK AND KESWICK CREEK UPGRADES FIGURE 15

Appendix E

Cost Estimate Report (Costplan)

Ref No. 20120679-R5B Lower Brown Hill Creek and Keswick Creek Upgrades Concept Report

Lower Brown Hill Creek Upgrade and Keswick Creek Diversions

Costplan Pty Ltd ABN 50 103 731 371 – U2 459 Morphett Street Adelaide SA 5000 08 82120202

Lower Brown Hill Creek and Keswick Creek Bypass – Revision 2. 4th March 2016 Page 1 of 14

Contents

1. Summary

1.1 Scope of report 1.2 Estimate summary 1.3 Approach and methodology 1.4 Main assumptions 1.5 Moving forward

2. Scope of Project

2.1 Project description 2.2 Documents reviewed 2.3 Limitations of estimate

3. Project Cost

3.1 Principals costs including Land acquisition 3.2 Construction Estimate 3.2.1 Estimate methodology 3.2.2 Box culvert supply 3.2.3 Construction Methodology 3.2.4 Estimate data & assumptions 3.3 Risks & Opportunities 3.4 Program & Procurement

4. Appendices

A. Estimate for Section 1 - 1 Lehunte Street to Keswick Barracks B. Estimate for Section 2 – Keswick Barracks channel upgrade C. Estimate for Section 3 – ANZAC Highway culvert diversions D. Estimate for Section 4 – Lower Brown Hill Creek upgrade

5. Revision Status

Revision No. 1 – 11th February 2016 Revision No. 2 – 4th March 2016

Lower Brown Hill Creek and Keswick Creek Bypass – Revision 2. 4th March 2016 Page 2 of 14

1. Summary

1.1 Scope of Report

Costplan Pty Ltd has been engaged by Mr. Michael Salkeld (Project Director, Brown Hill Keswick Creek Stormwater Project) to prepare updated estimates for this project in line with the most current hydrology and design.

This report is one in a series of that review and update previous estimates prepared. A key objective is to provide a consistent approach to the cost estimates for all elements of the project.

This report details development of the construction and project costs associated with two sections of the overall project. These are as follows- • The Keswick Creek Bypass/ Upgrade • The upgrade of Lower Brownhill creek

The report also explains Costplan’s view for the risk adjusted project costs based on the following parameters:

• Base date for the estimate is quarter one, 2016 • The project battery limits and scope are those described above and elsewhere in this report. • A traditional construct only tendering process and contract delivery • A risk allowance appropriate for a construction contract at a conceptual level of design. These allowances include both inherent risk and contingent risk to both the contractors and clients costs • The concept design detail is approximately 10% documented. The risk adjusted construction costs to include all allowances that a contractor would make in a competitive tender process for a construct only contract. • The estimates include previous expenditure on the design development to date

1.2 Estimate summary

Four estimates were prepared, three of which make up the Keswick Creek bypass option and the fourth includes the upgrade of Lower Brown Hill creek. These are as follows- • An additional culvert from Keswick creek at Le Hunte Street, across Goodwood road through the Adelaide show grounds, across the rail line and up Maple Avenue to Keswick barracks open channel immediately downstream of the Rail reserve. • The upgrade of the existing concrete lined channel of Keswick creek through the Keswick barracks through to ANZAC Highway. • The supply and installation of twin Reinforced concrete box culverts along ANZAC Highway linking Keswick Creek to Brown Hill creek • Lower Brown Hill Creek Channel upgrade from ANZAC Highway through to the downstream extent just west of Watson Avenue, Netley.

Lower Brown Hill Creek and Keswick Creek Bypass – Revision 2. 4th March 2016 Page 3 of 14

The estimated project costs for each of these cost centres are as follows-

Project Costs

Section 1 Lehunte – barracks $21.7m Section 2 Barracks $ 6.0m Section 3 ANZAC Bypass $15.4m Total for sections 1-3 (Keswick Creek bypass/ $43.1m upgrade)

Section 4 Lower Brown Hill Creek upgrade $39.1m

These estimates are divided into three major cost centres to assist with future cash flow predictions, risk assessment and procurement strategies. These cost centres are as follows; • Client’s costs: This cost centre includes the design development, project and contract management, community liaison requirements, services relocations and land acquisition requirements. • Contractor costs: This cost centre includes contractor’s preliminaries, onsite overheads, traffic management and environmental works, the supply and Installation of the upgrades, reinstatement works and the contractors overhead and profit allowances. • This includes project inherent and contingent risk.

Table 1.

Keswick Creek bypass / upgrade BROWN HILL CREEK Section 4 ITEM Sub Total STORMWATER UPGRADE Section 1, Le Section 2 Section 3 Lower BHC Hunte - Barracks Barracks ANZAC Design and Documentation, Project 1.1 $2,330,940 $830,222 $1,503,322 $4,203,927 $8,868,411 management etc. 1.2 Services relocations and alterations $573,985 $157,556 $1,503,322 $1,548,815 $3,783,678 1.3 Land Acquisition $350,000 $0 $0 $3,820,000 $4,170,000 TOTAL CLIENTS COSTS $3,254,925 $987,778 $3,006,643 $9,572,742 $16,822,089 2.1 Preliminaries and Onsite Overheads $1,597,078 $511,152 $1,251,837 $1,938,154 $5,298,220 Traffic management and environmental 2.2 $371,807 $114,699 $771,001 $611,794 $1,869,301 requirements 2.3 Contract Direct Costs $11,186,885 $2,989,131 $6,610,679 $17,564,536 $38,351,231 2.4 Contractor Overheads and margin $1,193,855 $323,909 $762,243 $2,011,448 $4,291,456 TOTAL CONTRACTOR COSTS $14,349,625 $3,938,890 $9,395,760 $22,125,933 $49,810,208

1+2 TOTAL WITHOUT RISK $17,604,550 $4,926,668 $12,402,404 $31,698,675 $66,632,297

3 RISK ALLOCATION $4,080,196 $1,115,011 $2,950,269 $7,371,520 $15,516,996

1+2+3 GRAND TOTAL $21,684,746 $6,041,679 $15,352,672 $39,070,196 $82,149,293

Lower Brown Hill Creek and Keswick Creek Bypass – Revision 2. 4th March 2016 Page 4 of 14

Client costs attributable to the Principal and design costs have been determined by Costplan Consulting based on benchmarked historical data and current trends. The costs for services and utility relocations have been calculated by both first principles and historical data. It should be noted that there can be considerable variance in predicting South Australian Power Networks and Telstra relocation costs. A major difficulty of this project will be working with limited access and in narrow residential streets. In particular the limited airspace available when excavating trenches and placing culvert units needed when restricted by wire and tree canopies.

1.3 Approach and Methodology

The scheduled item costs have generally been created and generally estimated from first principles. There are numerous services that cross (or run next to) the proposed works, in particular the bypass culvert routes that run down Le Hunte Street, the Goodwood Road crossing, across the rail reserve and down ANZAC Highway. The intent is to retain if possible all services where possible. Gravity Sewer mains, rail signalling / catenaries and trunk water mains will present the biggest challenges.

With this in mind we have allowed for 2 micro tunnelling operations so as to avoid some of these services clashes. These would include the jacking of three 1500 diameter pipes and associated transition structures to the proposed adjacent reinforced concrete box culverts.

The first location is adjacent the end of Le Hunte Street and across Goodwood Road to the showgrounds. A high volume of vehicles per day (in excess of 28,000) utilise this road, this combined with an adjacent service station and a SA Water trunk water main will all add to the projects risk.

The Rail Reserve (adjacent to Leader Street) which carries three metro rail tracks and the ARTC controlled freight line to Melbourne will also present considerable challenges if an open cut solution is adopted, particularly now as the metro lines are electrified and notwithstanding the political sensitivity of closing these lines.

Risk has been addressed by way of percentage on cost for the various elements and groups. Where our estimators believe there is greater risk for some elements than others they have reflected this as a greater percentage. For example, the supply cost for culverts has a much lower risk profile than the potential relocation of Telstra services.

Lower Brown Hill Creek and Keswick Creek Bypass – Revision 2. 4th March 2016 Page 5 of 14

1.4 Main assumptions

The key assumptions to which these estimates rely include the following:

• Undertaking the works to provide minimal practical disruption as possible. • Undertake the works during daylight hours and limiting night works to critical activities (e.g. ANZAC Highway works). • Costs are current as at January 2016 and escalation has been excluded. • Costs are inclusive of previous design development expenditure. • All costs are exclusive of the Goods and Services Tax.

1.5 Moving forward

When further development work is undertaken, we would recommend a number of actions that will have a large effect on the accuracy of the cost estimates, these include -

• Confirmation of culvert / wall sizes and location requirements. • Confirmation of the vertical alignments of the works. • Verification of existing service locations and seeking service authority’s requirements and quotations for relocations. • Completion of topographical surveys • Further design Development

Lower Brown Hill Creek and Keswick Creek Bypass – Revision 2. 4th March 2016 Page 6 of 14

2. Scope of Project

2.1 Project description

This project is for the construction of bypass culverts of various sizes between Brown Hill Creek (Downstream) and Keswick Creek / Le Hunte Street (Upstream). It also includes the widening of the existing channel and bridge replacements of Lower Brown Hill Creek from ANZAC highway down to Watson Avenue in Netley.

Table 2. Below summarises the various segments of these works.

LEG TREATMENT LENGTH (M) Keswick Creek Bypass Culvert Lehunte- Goodwood Road Single RCBC, 3300 x 1500mm 547 Goodwood Road crossing Micro tunneled 3 x 1500 RCP 25 Adelaide showgrounds Single RCBC, 3300 x 1500mm 593 Rail reserve Micro tunneled 3 x 1500 RCP 30 Mabel Street Single RCBC, 3300 x 1500mm 128 Keswick Barracks RC Channel widening 440 ANZAC Highway Twin RCBC 3600 x 1500mm 490 TOTAL M = 2253 Lower Brown Hill Creek upgrade RC open channel and ANZAC Highway - South Road Gabion structures 360 RC open channel and South Road - Grassmere reserve Gabion structures 520 Grassmere reserve - Birdwood Terrace Gabion walled structures 660 RC open channel and Birdwood Terrace - Marion Road Gabion structures 540 Marion Road - Watson Ave RC open channel and RCBC 660 TOTAL M = 2740

Lower Brown Hill Creek and Keswick Creek Bypass – Revision 2. 4th March 2016 Page 7 of 14

For the upgrade of Lower Brown Hill Creek there are five bridges of insufficient size that will be required to be upgraded along with a number of footbridges that will need to be removed and replaced to facilitate construction access.

Table 3. Bridge Works

LEG TREATMENT LENGTH Lower Brown Hill Creek upgrade addition of adjacent 1 Farnham Bridge addition 20 RCBC 2 Daly Road Bridge replacement Twin 3300 x 1800 RCBC 20

3 Marion Road Bridge replacement Major DPTI road 20 Twin 3300 x 1800 RCBC ( 4 Harvey Road Bridge replacement to extend 20m 40 downstream) 5 Watson Avenue Bridge replacement Twin 3300 x 1800 RCBC 20

120

We have adopted the various treatments for creek widening as shown in Tonkin Consulting’s figure 12. It should be noted that we have adopted the concrete lined alternative for section 8 (between ANZAC and Farnham) rather than the closed multi cell culverts as this treatment would incur a significant cost penalty.

The hydraulic modelling design assumes the insertion of a ‘choke’ in the existing Keswick Creek culvert immediately downstream of the diversions take-off point. The modelled choke is a 2m diameter orifice. In practice, the orifice could be a short length of pipe cast into a block inside the culvert (approximately 3 m wide x 2.9 m) with streamlining of the entry and exit ends.

2.2 Documents reviewed

This particular report is based on the routes and culvert sizes as presented in the Tonkin Consulting drawings set Plan No: 20120679_PLAN-001 (figures 1 -18) as received. A detailed site inspection was undertaken for the Lower Brown Hill Creek channel upgrade works by representatives from the Brown Hill Creek Project, the city of West Torrens, DPTI, Tonkin Consulting and ourselves in December 2015. From this draft creek widening treatments were discussed and proposed.

2.3 Limitations of estimate

The Estimate is limited by the detail provided in the documents which we believe are currently in the order of 5-15% design complete.

Numerous assumptions have been made where details were not shown on the drawings or drawings were not provided.

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3. Project Costs

3.1 Principal’s costs.

The principal’s costs include the following-

• Design and documentation. • Investigations (Survey, geotechnical, contamination etc). • Services locations and potholing. • Design verification and construction inspection. • Dilapidation surveys. • Project management and planning, • Community engagement and liaison. • Land acquisition.

For these estimates we have assumed that the majority of services relocations, street tree removals and pruning and culvert supplies will be undertaken by the principal.

Land acquisition costs are based on elemental data as previously prepared by Maloney Field Services. These have been amended to reflect the current route and escalated to reflect today’s dollars.

3.2 Construction estimate

3.2.1 Estimate methodology

These estimates were generally prepared from first principles in a manner similar to the development of a tender by an experienced construction contractor.

Construction costs are split into two main groups, Direct Costs and Preliminaries.

The first group, Direct Costs (DC’s) include the following sections: 1. Traffic and pedestrian management (typically 2-4 men required) 2. Environmental controls (mainly street sweeping duties). 3. Existing service relocations and protection (generally limited to service connections, existing stormwater modifications and relaying of top stones etc). 4. Culvert clearing, excavation, laying and backfilling. 5. Major structures and pits. 6. Road and street reinstatement works. 7. Miscellaneous works including tree root pruning, tree replacements, fencing etc.

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The second group, Contractors Preliminaries include the onsite overheads that cover the recurring and fixed costs required to deliver the project. These typically include the following:

• Supervision and staff allowances. • FIFO and LAHA allowances for staff if applicable. • Site vehicles. • Site equipment, small tools and general cranage. • Offices, site accommodation and statutory amenities. • Mobilisation of plant, equipment and men. • Insurances and fees. • The SA construction industry training levy. • Site service installations, removals and usage. • Training, safety requirements and inductions. • Survey. • Testing. • Demobilisation and site clean-up.

For these project options the total onsite overheads represent approximately 12% - 16% of the direct costs (DC’s). This is appropriate for this style of project.

As it is envisaged that this project will be delivered under a construct only model, allowances for design are included in the Principals cost section of the estimate.

An allowance of 10% (of both direct and indirect costs) for the contractor’s offsite overhead and margin has been allowed for, this is in line with recently benchmarked construction projects of similar size, complexity and with similar risk profiles.

Costs associated with the Contractors risks and opportunities (Inherent risk) are likely to be in the order of 5%.

Our estimates have been prepared using the guidelines of the Federal Government’s ‘Best practice cost estimation standard for publicly funded road and rail projects’ document as published in May 2011 by the Department of Infrastructure and Transport.

3.2.2 Box culvert supply.

A large portion of the cost for this project is the manufacture and supply of the culverts. The estimates allow for the supply and delivery of precast reinforced concrete box culverts that meet the requirements of AS 1597.1,2010 for small box culverts and AS 1597.2,1996 for large box culverts.

Budget rates for the manufacture, testing and delivery of these culverts were supplied by Humes, South Australia.

We would envisage a separate supply contract(s) for the box culvert crown and base units. This is easily managed, would alleviate any supply issues as manufactures only have so many moulds for any given size, it would also prevent the effect of margin on margin. Temporary stockpile locations would need to be carefully considered.

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3.2.3 Construction Methodology

The following methodology was subsequently adopted to be priced in the estimates: • Excavation: by conventional hydraulic excavators in the order of 25 – 30 tonnes. Material is to be carted to temporary stockpile sites for environmental testing and certification prior to being loaded and carted to appropriate off site dumps. • Bedding: An 80-100mm layer of sand supplied, laid and screeded to grade in order to receive culvert base units. • Placement of precast base slabs and crown units: dependent upon size, these units will generally weigh well in excess of the lifting capability of an excavator (used for excavation). Therefore a hydraulic crane up to 90 tonnes capacity will be required to install the majority of the units. A tractor crane will be required as it is unlikely that coordination of delivery truck can be timed exactly to when the units are scheduled to be installed. A security guard will also be required for nights to safeguard expensive cranes against vandalism. • Densopol tape is subsequently applied to the crown unit joints and the floor pockets grouted up. • We have allowed backfill to the sides of the units and to 200mm over the crown units to be with 1.5mpa CLSM. This facilitates speedy installation and assists in waterproofing the culvert units. • Backfill to the upper level to the existing pavement surface shall be with crushed rock. It is envisaged that once the main laying gang moves sufficient distance away then the top layer of the crushed rock can be excavated and reinstated with asphaltic concrete. • The leading edge of the main trench will need to be sandbagged/ plated over at the end of each day to act as end formwork and to maintain street access out of hours. • Service connections that are above the overt of the culvert will need to be either temporarily disconnected or removed and re-laid. Where these just under the invert of the culverts base slab protection may also be required. • Existing stormwater systems will also need to be reconfigured to discharge into the culverts.

It is expected that overall production rates of 5-15LM per day will be achieved. This is dependent upon culvert sizes, obstacles both underground and overhead, access, traffic and train management, dewatering and ground conditions.

When preparing first principal estimates of this nature due consideration should be given to ensuring production rates and plant adopted for individual tasks work within a daily cycle. That is trenching, bedding, placing units and backfilling all need to proceed at the same lineal metre rate per day in order to be trafficable after hours.

Due allowance has been made for the construction of the pits as shown on the drawings. These are significant structures in themselves and will take a considerable duration to construct. We would envisage that skewed box culvert units would be considered during the design development so as to both expedite the programme and increase the hydraulic efficiency of the design. In the absence of any preliminary designs inlet and outlet structures are “best guesses” based on previous experience.

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It is expected that final reinstatement will be undertaken once the main construction has advanced to a reasonable distance. For the larger sized culverts we have generally allowed for full road width reconstruction (150mm crushed rock, prime and a 40mm layer of asphaltic concrete) with the assumption that 50% of kerbing will be required to be replaced. This gives the option to slightly shift the horizontal alignment to avoid potential costlier service relocations.

3.2.4 Estimate data and assumptions

Estimate Data

During the preparation of the estimate the following materials and subcontractor budget prices were sought for the precast culvert units, micro tunnelling and shotcrete works with rates for ancillary materials being adopted and updated from other recent estimates Costplan has undertaken in this area.

Reinstatement costs include Kerbing, footpaths, landscaping and pavements to council or DPTI specification requirements.

A full suite of insurances and fees has been allowed for. This includes Contractors All Risk, Public Liability, Professional Indemnity, Work Place Health & Safety, Insurance Excesses and Security.

The statutory South Australian Construction Industry Training Board levy (CITBL) at 0.25 %( +GST) has also been allowed for. ` The labour rates calculated for the Project are as follows: Skilled labour $55 per hour Concrete workers $70 per hour Steel fixers and form workers $75 per hour, Trades personnel are based on $80 per hour

Plant rates adopted are based on competitive and current civil construction industry direct costs.

Estimate Assumptions

Given the conceptual nature of the design, numerous assumptions have been made during the preparation of these estimates. Whilst too lengthy to list in this report they appear as scope elements and notes in the body of the estimate proper. One such example is the shape, size and details of the junction box’s and inlet and outlet structures

Key assumptions are as follows:

• That the works will be carried out during normal daylight construction hours ( where possible) • We have utilised precast base slabs to expedite construction. • An allowance of one metre from the edge of the culvert to the edge of the trench to facilitate working space and edge forms if necessary • Backfilling the sides and to 200mm over the top of the trench with CLSM (as discussed above).

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3.3 Risks and opportunities

Risks

Risks are categorised as either inherent or contingent. Inherent risks are those that are known to occur but difficult to quantify. Risks such as slower production rates, dewatering, quantity inconsistencies etc are inherent.

Contingent risks are those that are generally unknown (and or unmeasurable) in nature. Risks such as unknown services, changes in standards and design development are contingent risks.

During the preparation of our estimates we have endeavoured to identify scope omissions and to quantify the obvious inherent risks. We have also included in the contractor’s scope an allowance of 5% for this.

In determining contingent risk we have placed differing contingent risk percentages on elements with different risk profiles. For example, existing service relocations at 35% to culvert supply at 10%. This equates to approx. 20 – 25% average contingent risk allowance.

These values are typical in terms of the current status of the concept design. As the design becomes more developed and certainties grow, this percentage will drop. At this stage of development we consider these levels appropriate.

Opportunities

Major opportunities have not been treated in any detail for these estimates. This is primarily due to the conceptual nature of the current design. These should be considered in more detail as the design develops and progresses.

3.4 Programme and Procurement

Although no detailed programme works have been prepared for these estimates, we envisage that these sections of the works will take in the order of three - five years to complete.

Due consideration needs to be given to approvals timeframes, design and investigation durations, Land acquisition, Service authorities constraints, cash flow constraints, industry resourcing availability and that the majority of works in existing channels be undertaken in the drier months to limit construction risk.

We would recommend that a draft programme be developed in parallel to the next stage of design development and budget updates so a more accurate cash flow can be developed.

Our current overview on procurement packaging would be to group the works into three discreet categories, these would include - • Supply and delivery of Precast Culverts and base units. • Minor works such as the micro tunnelling, smaller bridge widenings and reconstructions etc. • Major works in $5- $10m packages undertaken by tier 2 contractors.

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When determining project packaging due consideration needs to be given to clear battery limits so as minimise risk between both packages and flood risk.

Table 4 below details potential work packages

Work Packages Package 1 Culvert supply Package 2 Small bridge replacements Package 3 Marion Road bridge replacement Package 4 LBHC, Watson to Grassmere Package 5 LBHC Grassmere - ANZAC Package 6 ANZAC culverts Package 7 Micro tunnelling Package 8 Maple Avenue - Rail reserve Channel/ Culverts Package 9 Adelaide showgrounds Culverts Package 10 Le Hunte Street Culverts

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