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Acacia Bay Water Treatment Plant Options Assessment May 2017 Taupō District Council Mott MacDonald Level 1, 23 Union Street Auckland Central Auckland 1010 PO Box 37525, Parnell, 1151 New Zealand T +64 (0)9 375 2400 mottmac.com Taupō District Council 72 Lake Terrace Private Bag 2005 Acacia Bay Water Treatment Taupō Mail Centre 363167 1 B Taupō 3352 Plant P:\Auckland\NZL\01 Projects\363167 Acacia Bay WTP\04 Working\02 Documents\Options Study Report\2017-05-15_Acacia_Bay_Options_Assessment.docx Mott MacDonald Options Assessment May 2017 Mott MacDonald New Zealand Limited Taupō District Council Registered in New Zealand no. 3338812 Mott MacDonald | Acacia Bay Water Treatment Plant Options Assessment Issue and Revision Record Revision Date Originator Checker Approver Description A 10/5/2017 E. Wisniewski J. Ewert J. Ewert Draft for Client Review T. Ruland-Marsters B 15/05/2017 E. Wisniewski J. Ewert J. Ewert Final T. Ruland-Marsters Document reference: 363167 | 1 | B Information class: Standard This document is issued for the party which commissioned it and for specific purposes connected with the above- captioned project only. It should not be relied upon by any other party or used for any other purpose. We accept no responsibility for the consequences of this document being relied upon by any other party, or being used for any other purpose, or containing any error or omission which is due to an error or omission in data supplied to us by other parties. This document contains confidential information and proprietary intellectual property. It should not be shown to other parties without consent from us and from the party which commissioned it. This report has been pr epared sol el y for use by the party which commissi oned it (the ‘Client’) i n connecti on with the capti oned proj ect. It should not be used for any other purpose. N o person other than the Client or any party who has expressl y agreed ter ms of r eliance with us (the ‘Reci pient(s)’) may rel y on the content, i nformati on or any views expressed i n the repor t. We accept no duty of care, responsi bility or liability to any other r eci pient of thi s document. T his r eport is confi denti al and contains pr opri etar y intell ectual property. No representati on, warranty or under taking, expr ess or i mplied, is made and no responsi bility or liability is acc epted by us to any party other than the Cli ent or any Reci pient(s), as to the accuracy or completeness of the i nformati on contai ned i n this r eport. For the avoidance of doubt this r eport does not in any way purport to i nclude any legal , insur ance or fi nanci al advice or opi nion. We disclai m all and any liability whether arising i n tort or contract or other wise which it might otherwise have to any party other than the Cli ent or the Reci pient(s), in r espect of this report, or any infor mation attri buted to i t. We accept no r esponsibility for any error or omission i n the r eport which is due to an error or omission i n data, infor mation or statements supplied to us by other par ties incl udi ng the client (‘D ata’). We have not i ndependentl y verified such D ata and have assumed it to be accurate, complete, reli abl e and current as of the date of such infor mation. Forecasts presented i n this document were pr epared usi ng Data and the report is dependent or based on D ata. Inevitabl y, some of the assumptions used to develop the for ecasts will not be realised and unantici pated events and circumstances may occur. C onsequentl y M ott MacDonal d does not guarantee or warr ant the concl usi ons contained i n the repor t as there are li kel y to be differ ences between the for ecasts and the actual results and those di ffer ences may be material. Whil e we consi der that the infor mation and opini ons gi ven i n this r eport are sound all parti es must rel y on their own skill and j udgement when making use of it. Under no circumstances may this report or any extr act or summar y ther eof be used in connection with any public or pri vate securities offering i ncluding any rel ated memorandum or prospectus for any securities offering or stock exchange listing or announcement. 363167 | 1 | B | May 2017 P:\Auckland\NZL\01 Projects\363167 Acacia Bay WTP\04 Working\02 Documents\Options Study Report\2017-05- 15_Acacia_Bay_Options_Assessment.docx Mott MacDonald | Acacia Bay Water Treatment Plant Options Assessment Contents 1 Introduction 1 1.1 Background 1 1.2 Scope of Report 1 1.2.1 New Acacia Bay WTP (Option 1) 1 1.2.2 Connection to Taupō Water Supply (Option 2) 2 1.2.3 Assumptions 2 2 Design Criteria 3 2.1 Current and Projected Water Demands 3 2.2 Water Quality Requirements 6 3 Options Analysis 7 3.1 Option 1 – New Acacia Bay WTP 7 3.2 Option 2 – Connection to Taupō Water Supply 9 3.2.1 Effect on Lake Terrace WTP Upgrade Timeframes 11 4 Cost Comparison 14 4.1 Capital Cost Comparison 14 4.2 Operational Cost Comparison 15 4.3 Project Schedule Comparison 15 5 Identification of Risks 17 5.1 New Acacia Bay WTP 17 5.2 Connection to Existing Infrastructure 17 6 Conclusions 19 7 References 20 Appendices 21 A. MCA Analysis 22 A.1 Description of Parameters, Scoring and Weighting 22 A.2 Scoring Summary 23 A.3 MCA Matrix 24 B. Layout Drawings 25 363167 | 1 | B | May 2017 P:\Auckland\NZL\01 Projects\363167 Acacia Bay WTP\04 Working\02 Documents\Options Study Report\2017-05- 15_Acacia_Bay_Options_Assessment.docx Mott MacDonald | Acacia Bay Water Treatment Plant Options Assessment C. CAPEX and OPEX Costing 26 363167 | 1 | B | May 2017 P:\Auckland\NZL\01 Projects\363167 Acacia Bay WTP\04 Working\02 Documents\Options Study Report\2017-05- 15_Acacia_Bay_Options_Assessment.docx Mott MacDonald | Acacia Bay Water Treatment Plant 1 Options Assessment 1 Introduction 1.1 Background The Taupō District Council (TDC) is investigating options for providing the Acacia Bay community with a treated drinking water supply that complies with the requirements of the New Zealand Drinking Water Standard (NZDWS). TDC is considering two potential options to upgrade the existing Acacia Bay water supply to achieve compliance with the DWSNZ: the construction of a new water treatment plant (WTP) in Acacia Bay or connection of the Acacia Bay water supply to the existing water supply for Taupō. Both options have advantages and disadvantages to the Taupō and Acacia Bay communities in terms of meeting the water demand for both communities and ease in implementation of infrastructure and therefore a thorough comparison between the two options has been conducted to assist TDC to decide on the option to pursue. 1.2 Scope of Report The following report details an options comparison conducted between two options: construction of a new Acacia Bay WTP or connection to the existing water supply infrastructure for Taupō. To assist TDC with informing their LTP budgets and to assist in decision making, a high-level cost comparison has been conducted between the two options which includes concept capital cost estimates and high level operations cost estimates based on projected future water demand requirements for Acacia Bay and Taupō. 1.2.1 New Acacia Bay WTP (Option 1) The scope of this report includes the results of a location options study undertaken by Mott MacDonald in collaboration with TDC. This study involved the identification and comparison of several potential locations for a new WTP in the Acacia Bay area. A desktop mapping assessment initially identified a wide range of potentially suitable locations. A shortlist of locations was then determined based on a desktop assessment of agreed social acceptability criteria, technical issues, and planning restrictions to eliminate potential sites that were deemed to be fundamentally flawed in terms of: cultural and social aspects, environmental impacts, regulatory acceptance, or cost. The shortlist of potential WTP site locations were then visually assessed on-site with a TDC staff member to identify risks and challenges at each site and to score each site against pre-selected evaluation criteria. To compare and quantify engineering, monetary and non-monetary factors (e.g. cultural and social aspects, environmental impacts, regulatory acceptance etc.), a multi-criteria analysis (MCA) was completed for the shortlist of potential WTP site locations to generate a measurable outcome to identify the preferred Acacia Bay WTP location option for consideration and comparison against the alternative option of supplying Acacia Bay with NZDWS compliant water from the existing Taupō water supply. A high-level capital cost estimate was prepared for the preferred Acacia Bay WTP location option as part of this options assessment. This cost estimate was to a concept level of accuracy only and includes allowance for reticulation infrastructure (raw water pipeline to the WTP site, treated water pipeline to the existing reticulation system and backwash pipeline to sewer) and includes a project schedule (setting out the estimated spend profile over time). 363167 | 1 | B | May 2017 P:\Auckland\NZL\01 Projects\363167 Acacia Bay WTP\04 Working\02 Documents\Options Study Report\2017-05- 15_Acacia_Bay_Options_Assessment.docx Mott MacDonald | Acacia Bay Water Treatment Plant 2 Options Assessment 1.2.2 Connection to Taupō Water Supply (Option 2) The existing Lake Terrace WTP has a capacity of approximately 25 ML/d and was designed with the provision to increase capacity to 30 ML/d and 35 ML/d in two upgrade stages to accommodate growth and the potential connection of nearby communities such as Waitahanui and Acacia Bay.