RESOURCE CONSENT APPLICATION
Army Bay Wastewater Treatment Reconsenting Project
1535 Whangaparaoa Road, Army Bay
Mitchell Daysh Ltd
WATERCARE SERVICES LIMITED
ARMY BAY WASTEWATER TREATMENT PLANT
Assessment of Environmental Effects
November 2018 TABLE OF CONTENTS
Part A: Resource Consent Application
Part B: Assessment of Environmental Effects 1. Introduction ______1
1.1 Overview 1 1.2 Project Rationale 1 1.3 Resource Consents Required 3 1.4 Technical Reports 4 1.5 Report Structure 5 2. Evaluation of Alternatives ______6
2.1 Introduction 6 2.2 The Process 6 2.3 Best Practical Option 18 2.4 Preferred Option Summary 18 3. Project Description ______20
3.1 Introduction 20 3.2 Existing Army Bay WWTP 20 3.3 Exisiting and Future Service Areas 23 3.4 WWTP Upgrades and Discharge Quality 25 3.5 Discharges to Air – Odour 33 4. Exisiting Environment ______35
4.1 Physical Setting 35 4.2 Existing Wastewater Infrastructure 38 4.3 Cultural Setting 41 4.4 Ecological Values of the WWTP Site 43 4.5 Ecological Values of the Receiving Environment 47 4.6 Landscape, Amenity and Natural Character Values 57 5. Assessment of Effects ______60
5.1 Introduction 60 5.2 Positive Effects 62 5.3 Effects on Cultural Values 62 5.4 Hydrodynamic Modelling and Salinity 63 5.5 Coastal Water Quality 64 5.6 Effects of Microbial Contaminants 66 5.7 Effects on Benthic Habitats and biological Communities 68 5.8 Effects on Fish and Marine Mammal 70 5.9 Effects on Birdlife as a Result of Discharge Activities 71 5.10 Effects of Odour 71 5.11 Effects of the WWTP Upgrade Works on Ecological Values 73 5.12 Overall Conclusion of the effects of the WWTP discharges 76 6. Monitoring and Management Framework ______78
Watercare Services Limited – Army Bay Wastewater Treatment Plan – Resource Consent Application and Assessment of Environmental Effects
6.1 Introduction 78 6.2 Management Plans 78 6.3 Wastewater Monitoring 81 6.4 Benthic Habitats in the CMA 81 6.5 Water Quality in the CMA 81 6.6 Shellfish 81 6.7 Emerging Contaminants 81 6.8 Enivronmental Management Plan 82 6.9 Review of Environmental Monitoring Data 82 6.10 Annual Reporting 82 6.11 On-Going Consultation 83 7. Consultation ______84
7.1 Introduction 84 7.2 Iwi Consultation 84 7.3 Stakeholder and Public Consultation 86 8. Statutory Considerations ______89
8.1 Introduction 89 8.2 Auckland Unitary Plan – Operative in part 89 8.3 Section 104 Assessment 91 8.4 Section 105 – Matters Relevant to Discharge Applications 104 8.5 Section 107 – Restrictions to Grant Certain Discharge Permits 105 8.6 Part 2 Matters 106 8.7 Summary 107 9. Concluding Statement ______108
LIST OF FIGURES
Figure 1: Army Bay and the surrounding area. 1
Figure 2: Projected growth within the Army Bay WWTP catchment. 2
Figure 3: Flow Chart of Preferred Option Consideration process. 10
Figure 4: Existing Army Bay WWTP service area (shown in green). 20
Figure 5: Aerial photo of the existing Army Bay WWTP. 22
Figure 6: Outfall pipeline route. 23
Figure 7: Army Bay WWTP service area and projected development population. 24
Figure 8: Army Bay WWTP Upgrades - Stage 1 Concept Design 28
Figure 9: Army Bay WWTP - Stage 2 Concept Design Layout. 29
Figure 10: Army Bay WWTP - Stage 3 Concept Design Layout. 31
Watercare Services Limited – Army Bay Wastewater Treatment Plan – Resource Consent Application and Assessment of Environmental Effects
Figure 11: Staged upgrading of the Army Bay WWTP. 34
Figure 12: Army Bay WWTP site and the outfall point. 36
Figure 13: Wind rose for Whangaparaoa Peninsula (2009-2012). 37
Figure 14: Army Bay WWTP Network Upgrades. 40
Figure 15: Archaeological sites within the Army Bay WWTP service area. 42
Figure 16: Distribution of vegetation across the site. 45
Figure 17: Vegetation ecological values of the site. 46
Figure 18: Residual currents of the receiving environment. 48
Figure 19: Peak ebb (outgoing) tidal velocities of the receiving environment. 49
Figure 20: Peak flood (incoming) tidal velocities of the receiving environment. 49
Figure 21: QMRA sites. 67
Figure 22: Vegetation clearance required to upgrade the WWTP. 74
LIST OF TABLES
Table 1: Sixteen potential options. 7
Table 2: Comparison of remaining Short List Options. 14
Table 3: Preferred Option 1 – Proposed Discharge Median Limits. 17
Table 4: Staged Discharge Quality. 26
Table 5: Proposed discharge volumes. 26
Table 6: Existing and Stage 1 - Short-term Discharge Limits. 28
Table 7: Stage 2 – Medium-term Discharge Limits 30
Table 8: Stage 3 - Long-term Discharge Limits 31
Table 9: Nutrient Loads 32
Table 10: Water quality monitoring around Whangaparaoa Head. 50
Table 11: Parameters for scenarios considered for the assessment of ecological effects. 60
Table 12: Predicted loads for population scenarios considered. 61
Watercare Services Limited – Army Bay Wastewater Treatment Plan – Resource Consent Application and Assessment of Environmental Effects
Table 13: Proposed Final Army Bay WWTP wastewater quality standards. 61
Table 14: Percentile of dilution over the outfall, 50 m from the outfall, and 100 m from the outfall. 64
Table 15: Separation distances to high sensitivity receptors. 73
VOLUME 2 – APPENDICES
A: Certificate of Title.
B: Preferred Option Consideration Process – Army Bay Wastewater Treatment Plant Reconsenting Project, Watercare Services Ltd (November 2018).
C: Army Bay WWTP Consenting - Treatment Options, C2HM Beca Ltd (November 2018).
D: Ecological Assessment of a Proposed Wastewater Treatment Plant Upgrade at Army Bay, Whangaparoa, Wildlands (November 2018).
E: Assessment of Ecological Effects on the receiving environment from the discharge of treated wastewater from the Army Bay WWTP, Aquatic Environmental Sciences Ltd (November 2018).
F: Desktop Ecological Assessment of a Proposed Wastewater Treatment Upgrade on Avifauna Values at Army Bay, Whangaparoa, Wildlands (November 2018).
G: Army Bay Wastewater Discharge: Benthic Ecology, Coast & Catchment Ltd (October 2018).
H: Army Bay Wastewater Discharge – Review of fish and mammal resources, Coast & Catchment Ltd (March 2018).
I: Quantitative Microbial Risk Assessment for the discharge of treated wastewater at Army Bay, Streamlined Environmental (November 2018).
J: Army Bay Outfall Modelling, DHI (October 2018).
K: Army Bay WWTP – Technical Odour Assessment, C2HM Beca (November 2018).
L: Consultation Summary Table.
M: Auckland Unitary Plan Statutory Analysis.
Watercare Services Limited – Army Bay Wastewater Treatment Plan – Resource Consent Application and Assessment of Environmental Effects
A
PART A
Resource Consent Application
FORM 9
APPLICATION FOR RESOURCE CONSENT
Sections 88 and 145, Resource Management Act 1991
To Auckland Council
1. Watercare Services Limited (“Watercare”) apply for the following type(s) of resource consent:
• A discharge permit for a discretionary activity for the discharge of treated wastewater to the Coastal Marine Area;
• A discharge permit for a discretionary activity for the discharge of contaminant to air from the operation of the Army Bay Wastewater Treatment Plant (“Army Bay WWTP”);
• A land use consent for a restricted discretionary activity for the clearance of vegetation;
• A land use consent for a restricted discretionary activity for the clearance of vegetation from within a Significant Ecological Area;
• A land use consent for a restricted discretionary activity for land disturbance; and
• A land use consent for a discretionary activity for land disturbance within a Significant Ecological Area.
A 35 year term is sought for each of the discharge permits, and a 10 year term is sought for each of the land use consents.
2. The activity to which the application relates (the proposed activity) is as follows:
The proposed activity will enable the ongoing operation of the Army Bay WWTP for 35 years, and comprises the discharge of treated wastewater from the Army Bay WWTP to the Whangaparaoa Passage, approximately 1.1 km east of Huaroa Point at 1765500E 5948700N, the discharge of contaminants to air from the operation of the Army Bay WWTP, and vegetation removal and land disturbance required to upgrade the Army Bay WWTP.
The discharge of treated wastewater will be via the recently constructed outfall, and has been selected by Watercare through an extensive Preferred Option assessment, which comprised 16 options (with further sub-options) at the outset. The Preferred Option assessment included input from Watercare’s project team, Watercare staff, and Mana Whenua parties.
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A discharge of contaminants to air will result from the operation of the Army Bay WWTP. To manage this, Watercare propose to implement an Operations Management Plan or Air Quality Management Plan. As a result of management measures implemented, the discharge of odour will be unperceivable at the boundary of the site.
While not part of the proposed activity, except for the enabling vegetation clearance and land disturbance, key to the discharge of treated wastewater is the proposed upgrade of the Army Bay WWTP. The proposed upgrades will be implemented in advance of the population of the service areas reaching identified population totals, being 100,000 and 140,000, which is projected to be in approximately 2032 and 2042 based on current growth projections. There will also be some initial upgrades to the WWTP to service the current population growth and these upgrades are expected to be implemented by 2024. The quality of the treated wastewater will be progressively improved as the Army Bay WWTP is upgraded, ensuring the loads of contaminants remain below those assessed as part of the Assessment of Environmental Effects.
The vegetation removal and land disturbance required to upgrade the Army Bay WWTP comprises approximately 4,000 m2 within two 2,000 m2 areas to the south-west and north of the WWTP. Of this area, approximately 2,185 m2 is located within a Significant Ecological Area overlay and approximately 265 m2 of this vegetation is indigenous. To mitigate the loss of vegetation, approximately 4,242 m2 of mitigation planting will be undertaken.
The Assessment of Environmental Effects is supported by extensive technical and scientific investigations, which were undertaken to examine the effects of discharge and associated activities on the receiving environments, both now and in response to future population growth. Additional technical reports also considered the effects of the vegetation disturbance associated with the proposed WWTP upgrade works.
3. The site at which the proposed activity is to occur is as follows:
The Army Bay WWTP site is located at 1535 Whangaparaoa Road, Army Bay, and is 17.47 ha in area. The details of the site are set out in the table below.
Address Legal Description Title Area
1535 Whangaparaoa Allotment 695 Parish of Waiwera and Part NA42C/1167 17.47 ha Road, Army Bay Allotment 248-249, 339 Parish of Waiwera and NA93C/482
The Certificate of Title is provided as Volume 2, Appendix A.
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4. The full name and address of each owner or occupier (other than the applicant) of the site to which the application relates are as follows:
The site of the Army Bay WWTP is owned by Watercare Services Limited.
The discharge outfall point in the Coastal Marine Area is owned by Her Majesty the Crown.
5. The other activities that are part of the proposal to which the application relates are as follows:
The conservation planting undertaken in accordance with the Ecological Management Plan to be prepared for the WWTP site is provided for as a permitted activity in accordance with Table E15.4.2, Rule A37. This planting is for ecological enhancement purposes in line with Standard E15.6.3 of the Unitary Plan.
6. The following additional resource consents are needed for the Project to which this application relates and have not been applied for:
• The Outline Plan of Works for the upgrades of the Army Bay WWTP; and
• Any consents required for works on the conveyance network or discharges from the conveyance network.
Any future applications required will be made for these activities, and any other necessary consents, on an as needed basis.
7. I attach an assessment of the proposed activity’s effect on the environment that—
(a) includes the information required by clause 6 of Schedule 4 of the Resource Management Act 1991; and
(b) addresses the matters specified in clause 7 of Schedule 4 of the Resource Management Act 1991; and
(c) includes such detail as corresponds with the scale and significance of the effects that the activity may have on the environment.
8. I attach an assessment of the proposed activity against the matters set out in Part 2 of the Resource Management Act 1991.
9. I attach an assessment of the proposed activity against any relevant provisions of a document referred to in section 104(1)(b) of the Resource Management Act 1991, including the information required by clause 2(2) of Schedule 4 of that Act.
10. I attach the following further information required to be included in this application by the district plan, the regional plan, the Resource Management Act 1991, or any regulations made under that Act:
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• Assessment of Environmental Effects.
• Certificate of Title.
• Preferred Option Consideration Process – Army Bay Wastewater Treatment Plant Reconsenting Project, Watercare Services Ltd (November 2018).
• Army Bay WWTP Consenting - Treatment Options, C2HM Beca Ltd (November 2018)
• Ecological Assessment of a Proposed Wastewater Treatment Plant Upgrade at Army Bay, Whangaparoa, Wildlands (November 2018).
• Assessment of Ecological Effects on the receiving environment from the discharge of treated wastewater from the Army Bay WWTP, Aquatic Environmental Sciences Ltd (November 2018).
• Desktop Ecological Assessment of a Proposed Wastewater Treatment Upgrade on Avifauna Values at Army Bay, Whangaparoa, Wildlands (November 2018).
• Army Bay Wastewater Discharge: Benthic Ecology, Coast & Catchment Ltd (October 2018).
• Army Bay Wastewater Discharge – Review of fish and mammal resources, Coast & Catchment Ltd (March 2018).
• Quantitative Microbial Risk Assessment for the discharge of treated wastewater at Army Bay, Streamlined Environmental (November 2018).
• Army Bay Outfall Modelling, DHI (October 2018).
• Army Bay WWTP – Technical Odour Assessment, C2HM Beca (November 2018).
• Consultation Summary Table.
• Auckland Unitary Plan Statutory Analysis.
Signature:
Date: 22 November 2018
Mark Bourne Head of Servicing & Consents Watercare Services Limited
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Address for Service: Watercare Services Limited Tanvir Bhamji Private Bag 92 521 Wellesley Street Auckland 1141
Contact person: Tanvir Bhamji
Telephone: (09) 539 7494 Email: [email protected]
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1. INTRODUCTION
1.1 OVERVIEW
Watercare Services Limited (“Watercare”) provides high quality water and wastewater services to approximately 1.4 million people in the wider Auckland region. In respect of wastewater treatment, Watercare operates three large wastewater treatment plants (“WWTP”) at Mangere, Rosedale and Army Bay that service metropolitan Auckland, as well as a number of smaller treatment plants throughout the region.
The Army Bay WWTP currently services the communities of Whangaparaoa, Hibiscus Coast and Orewa. Wastewater treatment currently comprises an inlet screen / channel, sequential Batch Reactors (“SBR”), decant ponds, and ultra-violet (“UV”) treatment. Treated wastewater is discharged to the coastal marine area (“CMA”) approximately 1.1 km off the end of the Whangaparaoa Peninsula into the Whangaparaoa Passage.
This Assessment of Environmental Effects (“AEE”) has been prepared to support resource consent applications under the Resource Management Act 1991 (“RMA”) to authorise the activities associated with the continued treatment and discharge of wastewater from the Army Bay WWTP (“the WWTP”) (“the Project”), and to undertake the enabling works required to upgrade the WWTP.
Figure 1 provides an overview of the Army Bay WWTP and surrounding area.
Army Bay WWTP
Figure 1: Army Bay and the surrounding area.
1.2 PROJECT RATIONALE
Auckland Council forecasts the population of Whangaparaoa, Hibiscus Coast and Orewa will experience significant growth during the proposed 35 year consent term to 2053, from approximately 59,000 population equivalent (“PE”) currently to around 188,500 PE. Watercare has a statutory obligation under section 58 of the Local Government (Auckland
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Council) Act 2009 to give effect to Auckland Council plans. As growth is provided for through the wider planning documents through future development zones and future urban zones, Watercare is required to plan and provide for new water and wastewater facilities to service growth throughout the region. An overview of the projected growth is shown in Figure 2 below and this is the service area that Watercare has considered for this application.
Figure 2: Projected growth within the Army Bay WWTP catchment.
Watercare’s existing discharge permit (Permit No. 34088) for the Army Bay WWTP expires on 31 December 2021 however, due to population growth within the current service area, Watercare needs to be proactive in terms of ensuring that there is an appropriate long-term plan in place to meet its servicing obligations.
On this basis, Watercare’s primary Project Objective is to:
• Provide environmentally sustainable wastewater services to the Whangaparaoa, Hibiscus Coast and Orewa for the next 35 years and beyond.
This will be achieved by:
• Undertaking a robust alternative options assessment to provide Watercare, Auckland Council and the communities with confidence in the wastewater treatment solution chosen;
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• Selection of the best practicable option (“BPO”) for servicing the communities, with an ultimate capacity to service a population of approximately 188,500 (based on the Auckland Residential Futures Model);
• Providing a level of service and capacity that will also meet the future needs of the different types of land use activities identified in the Auckland Unitary Plan – Operative in part (“Unitary Plan”);
• Allowing for future expansion and modernisation of the WWTP, beyond 2053;
• Being consistent with the provisions of the Unitary Plan and other relevant statutory directions;
• Providing for an improved level of treatment that is appropriate for the receiving environment, while providing for the inclusion of cultural considerations into the decision-making process; and
• Obtaining the resource consents that will provide for the operation of the WWTP and works required to upgrade the WWTP, which are necessary to service the projected population growth.
This process has resulted in the identification of the Preferred Option for servicing the Whangaparaoa, Hibiscus Coast and Orewa communities based on population projections to 2053 and it is this option that is the basis for this resource consent application.
The Preferred Option has been described in further detail in Section 2 of this AEE.
1.3 RESOURCE CONSENTS REQUIRED
A full description of the resource consents required is provided below and a description of the relevant rules are provided in Section 8.2 of this AEE.
Watercare seeks all necessary resource consents from Auckland Council to authorise the discharge of wastewater and odour from the Army Bay WWTP, including the following:
• A discharge permit for a discretionary activity for the discharge of treated wastewater to the Coastal Marine Area at or about NZTM Map Reference 1765500E 5948700N; and
• A discharge permit for a discretionary activity for the discharge of contaminants to air from the operation of the Army Bay WWTP at or about NZTM Map Reference 1762620E 5948065N.
Furthermore, Watercare also seeks consents that will enable the upgrade of the WWTP, including:
• A land use consent for a restricted discretionary activity for the clearance of 1,815 m2 of vegetation;
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• A land use consent for a restricted discretionary activity for the clearance of 2,185 m2 of vegetation from within a Significant Ecological Area (“SEA");
• A land use consent for a restricted discretionary activity for 1,815 m2 land disturbance; and
• A land use consent for a discretionary activity for 2,185 m2 of land disturbance within a SEA.
The overall activity status is a discretionary activity under the Unitary Plan.
The discharge permits are sought for a 35 year period. The land use consents are required for a term of 10 years in order to provide for the upgrade works.
Resource consents are being sought to enable the Project (as described in this AEE) and the application intends to include all necessary consents for those activities to occur. In the event that the list of reasons for consent is not an exhaustive list and if further consent matters are identified post lodgement of the application, these should also be considered as forming part of this application. Notwithstanding, additional activities for which resource consents have not been applied for as part of this Army Bay WWTP process include:
• An Outline Plan of Works for the building works associated with the upgrade of the Army Bay WWTP; and
• Any consents required for works on the conveyance network or discharges from the conveyance network.
Any future applications required will be made for these, and any other consents relating to the Army Bay WWTP, on an as needed basis.
1.4 TECHNICAL REPORTS
This AEE draws information from a number of technical reports, prepared by independent technical advisers, which have been provided as part of Volume 2 of the AEE. These include the following:
• Assessment of Ecological Effects on the receiving environment from the discharge of treated wastewater from the Army Bay WWTP, Aquatic Environmental Sciences Ltd (November 2018);
• Desktop Ecological Assessment of a Proposed Wastewater Treatment Upgrade on Avifauna Values at Army Bay, Whangaparoa, Wildlands (November 2018);
• Army Bay Wastewater Discharge: Benthic Ecology, Coast & Catchment Ltd (October 2018);
• Army Bay Wastewater Discharge – Review of fish and mammal resources, Coast & Catchment Ltd (March 2018);
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• Quantitative Microbial Risk Assessment for the discharge of treated wastewater at Army Bay, Streamlined Environmental (November 2018);
• Army Bay Outfall Modelling, DHI (October 2018);
• Ecological Assessment of a Proposed Wastewater Treatment Plant Upgrade at Army Bay, Whangaparoa, Wildlands (November 2018);
• Army Bay WWTP – Technical Odour Assessment, C2HM Beca (November 2018);
1.5 REPORT STRUCTURE
All matters required to be addressed under the RMA are contained in this AEE, which is set out in nine sections, as follows:
Section 1 Is this introduction.
Section 2 Provides an overview of the Preferred Option Selection Process, details how the selection of the Preferred Option was made, and summarises the Preferred Option and the BPO consideration.
Section 3 Provides a description of the Army Bay WWTP, including, an outline of the service area, the existing and upgraded treatment processes, quality and quantity of discharge at the existing treatment plant, and the quantity and quality to be discharged following the Army Bay WWTP upgrade.
Section 4 Describes the existing environment in which the Army Bay WWTP operates.
Section 5 Provides an assessment of the effects on the environment of the discharges from the Army Bay WWTP and the vegetation clearance and land disturbance required to upgrade the WWTP.
Section 6 Provides an outline of the proposed monitoring and management framework in relation to the operation of the Army Bay WWTP.
Section 7 Provides an overview of the consultation undertaken by Watercare as part of the application process.
Section 8 Sets out the RMA framework which this application is to be assessed within including a detailed description of the consents required, an analysis of section 104 requirements including the provisions of relevant planning documents, and analysis under sections 105 and 107.
Section 9 Provides a concluding statement on the Army Bay WWTP application.
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2. EVALUATION OF ALTERNATIVES
2.1 INTRODUCTION
As part of the investigations to determine the most appropriate, practical and sustainable long-term wastewater treatment servicing option for the Whangaparaoa, Hibiscus Coast and Orewa communities, Watercare has undertaken a comprehensive assessment of the alternative treatment and discharge options available (“the Process”). The Process has been outlined in detail in the ‘Preferred Option Consideration Process, Army Bay Wastewater Treatment Plant Reconsenting Project, October 2018’ Report provided in Volume 2, Appendix B, and is summarised here.
2.2 THE PROCESS
Description of the Preferred Option Selection Process
The Process included input from a range of technical experts (including science, engineering, cultural, and statutory / planning) and stakeholders to assess the viable long- term wastewater treatment and discharge options and determine the “Preferred Option” for the wastewater servicing needs of the communities.
As part of the Process, the Project Objective and goals (refer to Section 1.2) were also identified, as these play an important role in guiding the outcomes of the Process.
The Process was characterised by:
• An approach that progressively provides a more detailed level of assessment by Watercare’s technical team as feasible options are identified;
• The application of evaluation criteria (“the Criteria”) based on applicable technical, environmental, planning, social and legal requirements; and
• Continued community, stakeholder and mana whenua engagement throughout the Process.
As a starting point Watercare’s Project Team identified the following 16 potential options for treatment and discharge of wastewater from the communities.
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Table 1: Sixteen potential options.
Option Treatment Discharge Option Description Number Location Location
1 Army Bay Army Bay outfall Continued use of the existing Army Bay Outfall WWTP pipeline for discharges of treated wastewater to the coastal marine environment.
2 New outfall The construction and use of a new outfall at alternative location/s to discharge treated wastewater from Army Bay WWTP.
3 Land Targeting suitable greenfield / land application sites application (5- within 5 - 10 km of the Army Bay WWTP (i.e. within 10km radius) Whangaparaoa Peninsula).
4 Land Targeting suitable greenfield / land application sites application (30 within 10 - 30 km of the Army Bay WWTP. km radius)
5 Non-potable The treated wastewater would be subject to reuse additional treatment to bring it to a suitable quality for non-potable reuse (e.g. industrial water use). The area to be considered is within reasonable pumping distance of the Army Bay WWTP (i.e. on the Whangaparaoa Peninsula).
6 Aquifer Treatment of wastewater to a quality suitable for recharge aquifer recharge requirements. The areas to be considered are known groundwater use aquifers within the growth areas.
7 New Army Bay outfall One or more new WWTPs would be built in a WWTP sensible location in proximity to the service population with continued use of the existing Army Bay outfall pipeline for discharges of treated wastewater to the coastal marine environment.
8 New outfall One or more new WWTPs would be built in a sensible location in proximity to the service population with the construction and use of a new
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Option Treatment Discharge Option Description Number Location Location
outfall at alternative location/s to discharge treated wastewater.
9 Rosedale outfall One or more new WWTPs would be built in a sensible location in proximity to the service population. Conveyance pipelines would be constructed to connect the new WWTP with the existing Rosedale outfall as a discharge location.
10 Land One or more new WWTPs would be built in a application sensible location in proximity to the service population. Targeting suitable greenfield / land application sites within a reasonable pumping distance of the WWTP (less than 10 km).
11 Potable reuse One or more new WWTPs would be built in a sensible location in proximity to the service population. The treated wastewater would be subject to additional treatment to bring it to a tertiary treatment quality. The area to be considered is within a reasonable pumping distance of the WWTP (less than 10 km).
12 Non-potable One or more new WWTPs would be built in a reuse sensible location in proximity to the service population. The treated wastewater would be subject to additional treatment to bring it to a suitable quality for non-potable reuse (e.g. industrial water use). The area to be considered is within a reasonable pumping distance of the WWTP (less than 10 km).
13 Aquifer One or more new WWTPs would be built in a recharge sensible location in proximity to the service population. Treatment of wastewater to a quality suitable for aquifer recharge requirements. The areas to be considered are known groundwater use aquifers within the growth areas.
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Option Treatment Discharge Option Description Number Location Location
14 Existing Rosedale outfall All or a portion of the wastewater from each WWTP catchment area would be pumped to Rosedale (either WWTP and discharged through the existing Rosedale, Rosedale outfall. Snells or 15 Helensville) Snells outfall All or a portion of the wastewater from each catchment area would be pumped to the proposed Snells Algies WWTP for treatment. Discharge would be as per the selected process for this WWTP, i.e. via the proposed Snells outfall
16 Helensville All or a portion of the wastewater from each outfall catchment area would be pumped to the existing Helensville WWTP and discharged as per the existing process, i.e. into the Kaipara River.
The overall objective of the Process was to progressively refine the sixteen potential options using an increasing level of assessment at each stage of the Process which comprised of the following stages (the references below are to the relevant section of the Report provided in Volume 2, Appendix B):
• Identification of Watercare’s Project goals and objectives (refer Section 1.2 and 1.3);
• Initial consultation with key stakeholders – late 2017 – early 2018 (Section 2);
• First Project Workshop (identification of potential servicing concepts) – October 2017 (Section 3.2);
• Second Project Workshop (Long-List Options Identification) – December 2017 (Section 3.3);
• First Mana Whenua focused hui / workshop – February 2018 (Section 2);
• First Public Open Days – February 2018 (Section 3.4);
• Third Project Workshop (Long List Options – Fatal Flaw Consideration) – February 2018 (Section 3.5);
• Stakeholder site visits – March 2018 (Section 3.4);
• Fourth Project Workshop (Short-List Options Consideration) – March 2018 (Section 4.2);
• Second Mana Whenua focused hui / workshop – April 2018 (Section 4.3);
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• Fifth Project Workshop (Preferred Option Consideration)– June 2018 (Section 5.3);
• Second Public Open Day – June 2018 (Section 5.4);
• Staging of the Preferred Option (Section 6); and
• Preferred Option Summary (Section 7).
This process is shown in Figure 3 below.
Figure 3: Flow Chart of Preferred Option Consideration process.
The detail within each section identified above has not been repeated here in the AEE however, a high level summary of the final stage has been provided below.
Final Process for Selection of the Preferred Option
2.2.2.1 Process Used
The final process for the selection of the Preferred Option included the following steps:
• Individual assessments from the BPO Workshop participants and technical experts against the Criteria relevant to their expertise;
• Incorporation of the community and iwi feedback;
• Preparation of the Comparison of Options table summarising all of the technical assessments and feedback;
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• Inclusion of financial considerations in terms of capital and operational costs with regard to the final three options; and
• Identification of the Preferred Option for the future discharge of wastewater from the three service areas (as referenced in Figure 2).
The general conclusions from this stage of the Process were:
• The construction of more than one new WWTP at locations in the vicinity of the Red and Yellow Zones was not a practical option as it was not realistic to request that ratepayers fund construction and operation of numerous additional WWTPs when there were existing assets available to provide the same services. There would also be additional consenting requirements (i.e. Notice of Requirements and Designations) for new plants and there is no certainty of the outcomes of such processes;
• The operation of multiple WWTPs and the associated conveyance network infrastructure does not equate to efficient and effective wastewater servicing due to the high capital and operational cost associated with building, operating and maintaining multiple WWTPs at different sites and the additional conveyance infrastructure required;
• Full land disposal is not possible given the total land area requirements, when considering the disposal option against the soil types, topography, existing land use and rainfall in the area. For the majority of each year (~ 7 months of each year), land disposal would not be possible, meaning that any such option would also require an alternative disposal method to provide for the discharge for the remainder of the year;
• The West Coast discharge option was not carried forward as it was not the preferred option of iwi who hold mana whenua over the West Coast receiving environment;
• There is potential for future re-use through managed aquifer recharge. However, there is not currently sufficient technical knowledge to support pursuing full or partial re-use at this time. This is a future option that Watercare is interested in investigating further along with potable reuse; and
• As the remaining options all discharged to the coastal environment, and the technical assessments have demonstrated that there will not be an adverse environmental effect as a result of discharging into this environment, the other factors relevant to each option are those which will direct which option is considered to be the Preferred Option.
2.2.2.2 Un-progressed Options
In terms of the short-list options, the following options were not progressed to the next phase:
• Option 8 (Development Plan C(i)) (Treatment at a new WWTP or WWTPs with a discharge to the West Coast) was not considered further as:
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• The construction of a new WWTP has the potential to have amenity and social impacts particularly if it is located within a residential area (which the yellow zone is earmarked for);
• Mana whenua were not entirely supportive of this as the preferred option particularly when there are already suitable discharge options available in the vicinity of the catchments where the wastewater was sourced from;
• The technical and operational aspects of the construction of an approximately 50 km conveyance line and additional outfall structure present significant costs and deemed unnecessary given the existing assets available;
• The construction of a long conveyance line to transfer treated wastewater limited future operational flexibility and new connections as, in the event that growth occurred between the new WWTP location and the outfall location, only treated wastewater could be connected to the line; and
• This option is inconsistent with Watercare's Project Objectives as follows:
• Objective iv) - As a new WWTP, conveyance line and outfall are required to be built for this option, there is uncertainty with regard to consenting a new WWTP location and associated infrastructure; and
• Objective vii) - This option is not entire supported by the iwi who hold mana whenua the West Coast, therefore, this option does not provide for mana whenua’s cultural objectives.
• Option 9 (Development Plan B(ii)) (Treatment at New WWTP and a discharge via the Rosedale outfall) was not considered further as:
• The construction of a new WWTP has the potential to have amenity and social impacts particularly if it is located within a residential area (which the yellow zone is earmarked for);
• It does not provide operational flexibility as the conveyance of treated wastewater to Rosedale means that any future developments between the new WWTP and Rosedale WWTP will not be able to connect to the conveyance line without receiving treatment first; and
• This option is inconsistent with Watercare's Project Objectives as follows:
• Objective iv) - As a new WWTP and conveyance line is required to be built for this option, and the Rosedale WWTP discharge consent expires in December 2030, there is uncertainty with regard to long-term consenting for this option, and
• Objective viii) This option does not provide for modernisation or flexibility as the construction of a conveyance line for treated wastewater only restricts any
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future connections to the line to be treated to the same level in order to avoid the need further doubling up of treatment.
• Option 10 (Development Plan B(iii)) (Treatment at a new WWTP or WWTPs with a discharge to land) was not considered further as:
• There is considerable difficulty acquiring enough land for full or partial disposal;
• Given the nature of the surrounding soils, topography and rainfall there will be and issues with discharging to land all year round;
• There is insufficient information on how long it would take for the discharge to reach groundwater or surface water, and what quality it would be by that point;
• It would create issues around discharges to land where the neighbouring land is Treaty settlement land and what impacts the use of land for wastewater irrigation may have on future uses of the Treaty land;
• While this option was not progressed, it was agreed that any preferred option should not preclude the potential for land disposal in the future; and
• This option is inconsistent with Watercare's Project Objectives as follows:
• Objectives iii) and iv) - As it will not provide a sufficient level of service to provide for the projected growth numbers and land use activities in the Red and Yellow Zone.
2.2.2.3 Progressed Options
The final two options that progressed to final comparison stage were:
• Option 1 (Development Plan A) – All zones (Blue, Red and Yellow) - expand and upgrade the Army Bay WWTP and continue to discharge through the Army Bay ocean outfall; and
• Option 14 (Development Plan E) - Blue and Red Zones - expand and upgrade the Army Bay WWTP and continue to discharge through the Army Bay ocean outfall. Yellow Zone – transfer untreated wastewater to Rosedale WWTP for treatment and discharge via Rosedale WWTP outfall.
2.2.2.4 Comparisons of Remaining Options
Following the above process, the two remaining options were subject to the next phase of the Process, which involved a comparison of the options against each other. The remaining options and a summary of the comparison are shown in Table 2 below.
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Table 2: Comparison of remaining Short List Options.
Annual Wastewater Total Major Option Operational Treatment Capital Cost Receiving Overall Summary Number Cost at Option to 2053 Environment 2053
1 All zones - $550 million $9.9 million Coastal Marine Enables Watercare to meet the long- Expand and Area - term wastewater servicing needs for (Development upgrade the Whangaparaoa the communities within the WWTP’s Plan A) Army Bay Passage catchment. WWTP and continue to This option provides an improved level discharge of treatment from the current through the consented limits. Army Bay ocean outfall; The effects of a discharge into the Whangaparaoa Passage are considered to be minor even under the 188,500 population figure.
The proposed 5 yearly technology and growth reviews will allow Watercare to respond to technology advances and growth and provide for operational flexibility during the proposed consent term and beyond.
While there is a higher capital cost for this treatment, a discharge into the Whangaparaoa Passage is a better discharge location due to the currents and flow environment of the Passage.
14 Blue and Red $487 million $8.9 million Blue and Red Blue and Red Zones are the same as Zones - Zone - Coastal for Option 1 above. (Development expand and Marine Area - Plan E) upgrade the Whangaparaoa Yellow Zone - While the effects of a Army Bay Passage discharge from the Rosedale Outfall WWTP and are consistent with the discharge continue to Yellow Zone - effects from the Army Bay outfall, a discharge Coastal Marine discharge into the Whangaparaoa through the Area -Mairangi Passage is considered the preferred Army Bay Bay discharge environment due to the ocean outfall. current and flow characteristics.
Yellow Zone – Rosedale WWTP’s current consents untreated are due to expire in December 2030 so wastewater this option does not provide long-term transferred to certainty for wastewater servicing Rosedale requirements as the Yellow zone is WWTP for targeted to come on line for treatment and development after 2030. discharge via Rosedale The lower capital cost for this aspect is WWTP outfall due to the conveyance line from the Yellow Zone to Rosedale being shorter than to Army Bay however, there are other factors that may affect this over time e.g. the construction of the Penlink Bridge.
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Considering the conclusions in respect of the matters in the table above, Option 1 (Development Plan 1) was selected as the ‘Preferred Option’.
In summary, as the two options both essentially discharge to the same receiving environment, the basis for the decision to select Option 1 is that it presents a more desirable discharge location, in terms of dilution and dispersal following discharge, from the existing Army Bay outfall within the Whangaparaoa Passage.
Further to the Preferred Option, Watercare’s position is that the selection of Option 1 as the Preferred Option does not preclude Option 14 (Development Plan E) being implemented in the future where it is determined that, through either growth requirements, technology improvements or changes to the receiving environments for the discharges (i.e. reuse or reinjection, etc), conveying wastewater to the Rosedale WWTP is appropriate.
Additionally, a primary driver for any future changes to Watercare’s operations is their commitment to continue to review their treatment and discharge process, and to explore alternative options regardless of the Preferred Option. To provide for this, Watercare propose to undertake technology and growth reviews at five yearly intervals. The purpose of such reviews will be to:
• Assess the actual population growth for the WWTP catchment areas against the forecasted growth and provide comparisons against the forecasted population growth the next five year period to assist in identifying the future upgrading timeframes for the WWTP; and
• Identify and assess any significant technological changes and advances in relation to wastewater management, inflow reduction, treatment, discharge and beneficial reuse technologies (including Managed Aquifer Recharge) that could be of relevance for possible future use including:
• options for wastewater reduction and/or reuse, including Managed Aquifer Recharge and industrial re-use, and any actions taken as a result of those investigations; and
• any discharge volume reduction that has been achieved as a result of any reuse or reduction actions.
It is considered that these reviews will ensure that the processes in place for wastewater treatment and discharge are consistent with the BPO considerations under the RMA and reflective of up to date technology for the duration of any resource consent. This will also enable Watercare to manage their wastewater servicing, treatment and discharges in an adaptive manner with a region-wide focus.
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Staging of the Preferred Option
Following the selection of the Preferred Option, Watercare subsequently held further focused workshops with its Project Team and mana whenua to inform the staged upgrade option selection process.
As part of these workshops C2HM Beca presented three separate technological options for the staging of the Army Bay WWTP upgrades as follows:
• Option A – Sequencing Batch Reactor (“SBR”) technology;
• Option B – SBR plus Ultrafiltration; and
• Option C – Membrane Bioreactor Reactor (“MBR”) technology.
For the purpose of this exercise Watercare considered the existing capacity of the WWTP (~60,000 PE) and identified four stages (based on growth projections) that would be the triggers for WWTP capacity upgrades. Key aspects of the consideration process were the:
• Extent of disturbance of the SEA within the WWTP site required for each option;
• Expected discharge quality limits provided for at each stage; and
• Concept design assumptions of each stage of the upgrades.
There was agreement from all parties that Option C, being the staged conversion of the Army Bay WWTP to MBR treatment technology, was the Preferred Option for the staged upgrade of the WWTP because:
• The construction footprint had the lowest area of SEA disturbance;
• It provides the best long-term effluent discharge quality limits; and
• It provides Watercare with some futureproofing and operational flexibility to service growth beyond the proposed 35 year consent term or in the event that growth increases faster than that which is forecasted.
In terms of proposed discharge limits, Option C provides for the limits in Table 3 below.
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Table 3: Preferred Option 1 – Proposed Discharge Median Limits.
Parameter Units Existing Consent Stage 1 – Serviced Stage 2 - Serviced PE Stage 3 - Serviced PE (Retained until PE ~60,000 – ~100,000 – 140,000 ~140,000 – 188,500 Stage 1 operational 100,00 ~ 5 years)
Median 92nd Median 92nd %ile Median 92nd %ile Median 92nd %ile %ile
3 cBOD5 g O2/m 20 35 5 20 5 20 5 20
TSS g/m3 35 75 15 30 15 30 5 20
3 NH4-N g N/m 15 N/A 5 15 5 15 5 15
Total N g N/m3 N/A N/A 15 30 10 20 10 20
E. Coli cfu/100 N/A N/A 10 150 10 150 10 150 mL
Enterococ cfu/100 100 1000 10 150 10 150 10 150 ci mL
The Preferred Option
As a result of the information presented and discussed at the workshops and through the consultation / engagement process, Option 1 is identified as the Preferred Option for the long-term treatment and discharge of wastewater from the Whangaparaoa, Hibiscus Coast and Orewa communities for the following reasons:
• The Preferred Option has been determined through a robust options assessment process which has included specific input from mana whenua, stakeholders and the public;
• Following the proposed site upgrades, the Army Bay WWTP will have the capacity to provide for the servicing needs of the anticipated 188,500 population based on the Council’s growth forecasts and will also service the range of land uses identified within the WWTP’s service areas;
• The proposed discharge limits will provide an improvement in the discharge quality from what is currently consented;
• In the event that it is determined to be practicable and appropriate, the proposed MBR upgrades within the Army Bay WWTP site footprint provide for further expansion beyond the proposed consent term;
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• The involvement of mana whenua in the selection process ensured that the Process recognised, and to the greatest extent practicable, provided for cultural values and interests;
• The proposed MBR upgrades provide a modern treatment option, while the proposed growth and technology reviews will enable Watercare to appropriately respond to advancements in technology, which may affect the need for wastewater to be directed to the Army Bay WWTP for discharge to the coastal environment.
2.3 BEST PRACTICAL OPTION
Finally, when considering the Preferred Option against section 105 of the RMA, which sets out matters relevant to discharge applications, it was found that:
• With regard to section 105(1)(a) – the final discharge limits proposed are an improvement on those which are currently consented at the Army Bay WWTP and as such, minimise potential effects on the CMA. While there will be an increase in loads as the population increases, the effects of this increase have been identified as not having an adverse effect on the receiving environment due to improvements in treatment technology and the significant dilution experienced at the discharge location. Additionally, when compared against the current discharge quality, there will an improvement in discharge concentrations over the proposed consent term particularly as the total nitrogen (“TN”) concentration limit becomes 10 g N/m3 (Median limit) and total suspended solids (“TSS”) becomes 5 g/m3 (Median limit);
• With regard to section 105(1)(b) – When compared against Option 14, which has a slightly lower capital cost for construction, the financial implication on Watercare of spending marginally more money for Option 1 is justifiable as the technical assessments (dilution modelling and ecological assessments) have demonstrated that, while discharges to each of the receiving environments is are environmentally acceptable and comparable, a discharge to the Whangaparaoa Passage is preferred due to the flow rates / currents present which provide for marginally better dilution following the discharge particularly given that there is an existing conveyance network in place to the Army Bay WWTP for the majority of the catchment areas; and
• With regard to section 105(1)(c) – Current WWTP technology is sufficient to enable Watercare to operate a high quality WWTP at Army Bay that will produce treated wastewater of sufficient standard / quality that it will have no adverse effect on the receiving environment.
2.4 PREFERRED OPTION SUMMARY
Watercare considers that a robust and transparent process has been followed with regard to determining the preferred wastewater treatment and discharge options for the Whangaparaoa, Hibiscus Coast and Orewa communities. This has led to the selection of an
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overall Preferred Option for the Army Bay WWTP which is consistent with the BPO as defined under the RMA and meets Watercare’s Project Objectives.
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3. PROJECT DESCRIPTION
3.1 INTRODUCTION
This section provides a description of the existing Army Bay WWTP and also the proposed upgrades to the WWTP over the proposed 35 year consent term. This section provides a high-level summary of the technical details provided in the CH2M Beca Report ‘Army Bay WWTP Consenting – Treatment Options’ (“Beca Treatment Options Report”) provided as Volume 2, Appendix C.
3.2 EXISTING ARMY BAY WWTP
Army Bay WWTP and Service Area
The Army Bay WWTP was commissioned in 1982 to serve the communities of Whangaparaoa, Hibiscus Coast and Orewa with Hatfields Beach being connected shortly after. Currently, the WWTP has capacity for approximately 60,000 PE.
The 17.47 ha site is located at 1535 Whangaparaoa Road, Army Bay (“the site”) and is designated (Designation #9362) for “Wastewater Purposes – Sewerage Treatment and Disposal, Watercare Services Ltd” under the Unitary Plan.
The service area and wastewater network are shown in Figure 4 below.
Figure 4: Existing Army Bay WWTP service area (shown in green).
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3.2.1.1 Current Wastewater Treatment and Discharge
A detailed description of the current treatment process are provided in Section 4 of the Beca Treatment Options Report. As a summary, the Army Bay WWTP currently comprises the following treatment processes:
• Inlet chamber;
• Inlet screen and screenings handling;
• Grit removal and grit handling;
• Flow splitting;
• Sequencing Batch Reactors (“SBR”);
• Decant Ponds;
• Outfall pump station;
• UV Treatment; and
• Coastal outfall pipeline.
Outside of the treatment process, the WWTP also features:
• Waste activated sludge (“WAS”) storage tanks;
• Gravity belt thickeners for thickening WAS;
• Thickened waste activated sludge (“TWAS”) storage tanks;
• Centrifuges for dewatering TWAS;
• Dewatered sludge bins; and
• Biofilters for treatment of foul air from the inlet works and sludge handling areas.
The Average Dry Weather Flow (“ADWF”) provided for under the current discharge permit is approximately 32,147 cubic metres per day (“m3/d”) however, the current discharge capacity of the WWTP is 350 litres per second (“L/s”) (due to the flow restrictions of the current outfall) which equates to approximately 30,200 m3/d. Treated wastewater is discharged to the coastal marine area (“CMA”) approximately 1.1 km off the end of the Whangaparaoa Peninsula in the Whangaparaoa Passage.
An aerial photo the existing Army Bay WWTP is shown in Figure 5 below.
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Figure 5: Aerial photo of the existing Army Bay WWTP.
Since 2014 the WWTP has demonstrated compliance with its discharge quality limits.
3.2.1.2 Discharge to Air
The operation of the WWTP results in the discharge of odour to air. Processes at the existing WWTP with the greatest potential to give rise to odour effects are:
• The inlet screening and collection area plant odour control unit;
• The solids handling and dewatering building, and WAS storage tank odour control unit; and
• SBR units.
Foul air from the screens and the sludge handling processes are extracted and passed through biofilters. The biofilters remove the compounds that result in nuisance odour emissions. There are no specific odour controls in place for the SBR ponds.
No odour nuisance complaints have been received by Watercare or Auckland Council regarding the operation of the WWTP.
Coastal Outfall Pipeline
The existing coastal outfall pipeline currently discharges approximately 1.1km (the pipeline length is approximately 1.3km but due to the kink in the line it discharges closer to the coast) off the Whangaparaoa Peninsula into the Whangaparaoa Passage. The Army Bay WWTP outfall pipeline is currently being replaced with a new outfall pipeline, which is scheduled for completion in December 2018. This work is authorised by Auckland Council consents LAN-67051, REG-67054, REG-67055, COA-67056 and REG-67058. Figure 6 shows the route of the pipeline.
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Figure 6: Outfall pipeline route.
Once completed, the new outfall pipeline will provide a flow capacity of 1,400 L/s. The outfall can be further upgraded to a maximum capacity of 1,900 L/s, which can be achieved by increasing the diameter of the diffuser section of the pipeline or adding a second diffuser section. Any future works associated with an outfall upgrade that require additional consents will be sought at the time.
3.3 EXISITING AND FUTURE SERVICE AREAS
The Army Bay WWTP currently serves the communities of Whangaparaoa, Orewa and Silverdale, and in the future will also serve the communities of Hatfields Beach, Wainui, Dairy Flat, Stillwater, Okura Bush and Redvale as development in these areas occurs. Projected development in these areas is shown in Figure 7.
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Figure 7: Army Bay WWTP service area and projected development population.
As shown in Figure 7, the service area will expand over the proposed consent term (35 years) generally as follows:
• The WWTP service area through to 2030 will comprise the existing Whangaparaoa, Orewa, Silverdale and Stillwater communities (shown in blue in Figure 7), and the eastern Wainui / northern Dairy Flat community that is currently being progressively developed from north to south (shown in red in Figure 7). The population in these areas is anticipated to grow from approximately 59,000 to 100,000 by 2032;
• Following 2032, the WWTP service area will add the southern Dairy Flat and Redvale communities to the Army Bay WWTP (shown in yellow in Figure 7). Development in these areas is currently scheduled for beyond 2030 and will comprise and mixture of residential (currently zoned Future Urban Zone) and Business Light Industry. The development of this area along with the ongoing development of the blue and red areas
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in Figure 7 is projected to increase the Army Bay WWTP serviced population from 100,000 to 188,500.
3.4 WWTP UPGRADES AND DISCHARGE QUALITY
Overview
Watercare propose that the existing Army Bay WWTP be upgraded in a staged manner to provide sufficient capacity to service the forecasted growth within the Hibiscus Coast, Whangaparaoa and Orewa communities over the requested 35 year consent term. It is proposed that the WWTP will be upgraded using modern technology to produce high-quality treated wastewater suitable for discharge to the coastal environment off the Whangaparaoa Peninsula.
Ultimately the WWTP will comprise of an MBR Plant with UV treatment, with the conversion from the existing SBR process undertaken in a staged approach consistent with population growth. To provide for this, Watercare seek to operate the WWTP under four timeframes being:
• Existing WWTP – the WWTP will have to operate under the existing treatment capacity and discharge quality until the Stage 1 upgrades can be implemented being ~ 5 year from the granting of consent;
• Stage 1 (short-term) – from when the Stage 1 upgrades are operational until the inflow to the WWTP reaches an average dry weather flow (“ADWF”) of 22,500 m3/d;
• Stage 2 (medium term) – from when the Stage 2 upgrades are operational until the inflow to the WWTP reaches an ADWF of 31,500 m3/d; and
• Stage 3 (long-term) - from when the Stage 3 upgrades are operational until end of the consent term.
Watercare propose that each of these stages are subject to different discharge limits, as outlined in Table 4 below, as these limits reflect the performance of the staged upgrades. Watercare note that this approach is consistent with that which was authorised under recent Warkworth / Snell-Algies WWTP consents granted in July 2017.
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Table 4: Staged Discharge Quality.
Parameter Units Existing Consent Stage 1 – Serviced Stage 2 - Serviced PE Stage 3 - Serviced PE (Retained until PE ~60,000 – ~100,000 – 140,000 ~140,000 – 188,500 Stage 1 operational 100,00 ~ 5 years)
Median 92 %ile Median 92 %ile Median 92 %ile Median 92 %ile
3 cBOD5 g O2/m 20 35 5 20 5 20 5 20
TSS g/m3 35 75 15 30 15 30 5 20
3 NH4-N g N/m 15 N/A 5 15 5 15 5 15
Total N g N/m3 N/A N/A 15 30 10 20 10 20
E. Coli cfu/100 N/A N/A 10 150 10 150 10 150 mL
Enterococ cfu/100 100 1000 10 150 10 150 10 150 ci mL
The proposed discharge volumes are based on Auckland Council’s forecasted population numbers and would be the trigger for when each staged upgraded would need to be operational by. These volumes are shown in Table 5 below.
Table 5: Proposed discharge volumes.
Population ~60,000 PE ~100,000 PE ~140,000 PE ~188,500 PE Estimate
Average Dry 13,275 m3/d 22,000 m3/d 31,000 m3/d 42,410 m3/d Weather Flow
Peak Dry 39,825 m3/d 65,400 m3/d 92,000 m3/d 129,000 m3/d Weather Flow
Peak Wet 615 L/s 1,010 L/s 1,417 L/s 1,964 L/s Weather Flow
It is proposed that each discharge volume will apply up until Watercare can certify the implementation of the following stage’s upgrades. It is noted that the actual discharge volumes will only increase as a result of the inflow of wastewater from the population increase over time.
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The WWTP upgrades and discharge quality has been described in detail in the CH2M Beca Technical WWTP Report (Volume 2, Appendix C) and has been summarised below. It should be noted that the upgrades described are still only concept designs and will be subject to final design considerations in the event that consent is granted.
Existing Treatment and Stage 1 - Short-Term Wastewater Treatment
In order to provide sufficient time for the final design, consenting, construction and implementation of the Stage 1 WWTP upgrade, Watercare propose to continue to operate the WWTP under its current discharge quality limits for a period of up to 5 years from the date of commencement of the resource consents granted for the Project. This will enable Watercare to continue to meet the needs of the population within the serviced area until Stage 1 is operational (approximately 2024).
The CH2M Beca concept design outlines that the proposed Stage 1 upgrades, to provide for up to 100,000 PE, would include the following:
• Retention of the existing three SBRs operating as they currently are and treating 60% of the total inflow to the WWTP;
• Installation of a new MBR plant constructed adjacent to the SBRs to treat the remaining 40% of the inflows. The MBR will be constructed to achieve a TN concentration of ~10 g/m3 and, with the membrane filtration used for solids/liquid separation, would achieve a TSS concentration of ~5 g/m3; and
• If not achieving the required treatment, the UV Plant will be upgraded to meet 3-Log reduction in viruses; and
• The discharges from the SBR and MBR would be combined in the decant pond prior to being pumped to the UV disinfection and discharged via the upgraded outfall.
Figure 8 below shows the Stage 1 concept design layout for the WWTP upgrade.
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Figure 8: Army Bay WWTP Upgrades - Stage 1 Concept Design
Table 6 sets out the wastewater quality parameters the Army Bay WWTP would be operated under for the existing operations and then those following the implementation of the Stage 1 upgrade. It is proposed that the Stage 1 limits apply up to the point where the inflows to the WWTP reach an ADWF of 22,000 m3/d.
It is noted that the current consent does not contain limits for Total N or E.coli, but based on Watercare’s current monitoring, the Army Bay WWTP is currently achieving median values of 15 g N/m3 and 10 cfu/100 mL, and 92nd percentile limits of 25 g N/m3 and 150 cfu/100 mL therefore, it is proposed that these values are applied from the commencement of consent.
Table 6: Existing and Stage 1 - Short-term Discharge Limits.
Parameter Units Existing Consent Stage 1 up to 22,000m3/d. Limits (~100,000 PE)
3 cBOD5 g O2/m 20 (35) 5 (20)
TSS g/m3 35 (75) 15 (30)
3 NH4-N g N/m 15 (N/A) 5 (15)
Total N g N/m3 15 (30) 15 (30)
E. Coli cfu/100 mL 10 (150) 10 (150)
Enterococci cfu/100 mL 100 (1000) 10 (150) Note 1: Number in brackets is the 92nd percentile limit. Note 2: Underlined limits are new proposed limits
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As shown in Table 6 above, following the implementation of the Stage 1 upgrades, there will be an immediate improvement to the discharge quality limits when compared against the currently consented discharge limits.
Stage 2 - Medium-Term Wastewater Treatment
Prior to the ADWF reaching 22,000 m3/day (~100,000 PE at approximately 2032), Watercare propose to implement the Stage 2 Army Bay WWTP upgrades. The CH2M Beca concept design outlines that the proposed Stage 2 upgrades would include the following:
• Implementation of additional membrane trains to increase the proportion of flow treated by the MBR, giving it a capacity of 80,000 PE (~80% of the inflow); and
• Upgrading of the existing SBRs to improve the nitrogen removal process, with the aim of achieving an effluent TN concentration below 10 g/m3 (median).
• The discharges from the SBR and MBR would be combined in the decant pond prior to being pumped to the UV disinfection and discharged via the upgraded outfall.
Figure 9 below shows the Stage 2 concept design layout for the WWTP upgrade.
Figure 9: Army Bay WWTP - Stage 2 Concept Design Layout.
Table 7 sets out the proposed wastewater discharge limits following the completion of the Stage 2 upgrades. These limits would apply until the serviced population reaches an ADWF of 31,000 m3/d.
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Table 7: Stage 2 – Medium-term Discharge Limits
Parameter Units Stage 1 - Stage 2 – Medium-term Limits up to Short- 31,000m3/d (~140,000 PE) term Limits
3 cBOD5 g O2/m 5 (20) 5 (20)
TSS g/m3 15 (30) 15 (30)
3 NH4-N g N/m 5 (15) 5 (15)
Total N g N/m3 15 (30) 10 (20)
E. Coli cfu/100 mL 10 (150) 10 (150)
Enterococci cfu/100 mL 10 (150) 10 (150) Note 1: Number in brackets is the 92nd percentile limit. Note 2: Parameter shown in BOLD indicates an improvement in discharge quality.
The key change from the short-term to the medium-term discharge quality limits is a reduction in the median and 92nd percentile of TN from 15 and 25 g N/m3 respectively, to 10 and 20 g N/m3.
Stage 3 – Long-Term Wastewater Treatment
Prior to the ADWF reaching 31,500 m3/day (~140,000 PE at approximately 2042), Watercare will implement further upgrades (Stage 3) at the Army Bay WWTP to enable it to service the long-term wastewater needs of the communities. The CH2M Beca concept design outlines that the proposed Stage 3 upgrades would include the following:
• Conversion of the existing SBRs to flow through activated sludge reactors; and
• Implementation of additional membrane trains to increase the proportion of flow treated by the MBR to 100%.
Figure 10 below shows the Stage 3 concept design layout for the WWTP upgrade.
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Figure 10: Army Bay WWTP - Stage 3 Concept Design Layout.
Table 8 sets out the wastewater discharge limits the completion of the Stage 3 upgrade which would apply until the end of the proposed 35 year consent term.
Table 8: Stage 3 - Long-term Discharge Limits
Parameter Units Medium-term limits Stage 3 - Long-term limits (up to ~188,500 PE) (see Table 7)
3 cBOD5 g O2/m 5 (20) 5 (20)
TSS g/m3 15 (30) 5 (20)
3 NH4-N g N/m 5 (15) 5 (15)
Total N g N/m3 10 (20) 10 (20)
E. Coli cfu/100 mL 10 (150) 10 (150)
Enterococci cfu/100 mL 10 (150) 10 (150) Note 1: Number in brackets is the 92nd percentile limit. Note 2: Parameter shown in BOLD indicates an improvement in discharge quality.
The key change from the medium-term to the long-term discharge quality is a reduction in the median and 92nd percentile TSS from 15 and 30 g N/m3 respectively to 5 and 20 g N/m3.
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Nutrient Loads
As the inflows to the WWTP increase (as a result of the growing population being serviced) there will be an increase in the nutrient loads discharged from the WWTP. The estimated nutrient loads are as follows:
Table 9: Nutrient Loads
Parameter ~2018 Existing ~2032 100,000 ~2042 ~2054 60,000 PE PE 140,000 PE 188,500 PE
cBOD5 (t/yr) 12 40 56 77
TSS (t/yr) 31 40 56 77
Ammoniacal 12 40 56 77 Nitrogen (t/yr)
Total N (t/yr) 53 96 112 155
Discharge Quality Summary
Overall, when comparing the existing limits to those proposed following the implementation of Stage 3, the TN limit will decrease from a median of 15 g N/m3 and 92nd percentile limit of 25 g N/m3 to 10 g N/m3 and 20 g N/m3 respectively.
Additionally, the TSS limits decrease from a median of 15 g/m3 and a 92nd percentile of 30 g/m3 to 5 g/m3 and 20 g/m3respectively. There will also be the provision of set limits for both E. Coli and Enterococci.
Further, the increased flows into the WWTP will result in an increase in the nutrient loads being discharged.
An assessment of the actual and potential effects of these discharge to the receiving environment, and also the land-based activities associated with the installation of the WWTP Upgrades, is provided for in Section 5 below.
The Upgraded Army Bay WWTP
Overall, Watercare proposes to progressively upgrade the WWTP in three stages as described above. When fully upgraded, it is proposed that the Army Bay WWTP will provide for:
• A design population of approximately 188,500 PE;
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• A design ADWF 42,410 m3/d;
• A design peak wet weather flow of 1,964 L/s; and
• Have the ability to add further capacity to provide for future growth.
It is important to note that the actual timing of the upgrades will be driven by population growth and servicing demand and not a fixed date (i.e. Stage 2 by ~2032). Additionally, any upgrades would need to be operational prior to the population being serviced reaching the targeted treatment capacity.
The concept design of the fully commissioned WWTP upgrades (each stage is colour-coded) is provided in Figure 11 below.
As a result of the increased flows to the WWTP, due to the production of biosolids requiring disposal offsite from the solids thickening and dewatering process, the number of truck movements from the site is expected to increase from three (3) to eight (8) per day once the WWTP is servicing a 188,500 PE.
3.5 DISCHARGES TO AIR – ODOUR
The processes at the upgraded WWTP with the highest potential to give rise to odour effects are expected to be:
• WAS and TWAS storage tanks;
• Solids handling and dewatering facility; and
• Inlet screening works.
The existing WWTP will continue to capture odorous air discharges at each of the locations above and treat them through the biofilters onsite.
For the WWTP upgrades, the concept designs have provided for further cover and ventilation of air from the inlet works headspace, the WAS storage tank, sludge thickening and dewatering equipment and the biosolids processing building. The air extracted will be treated in biofilters to achieve the required treatment to eliminate nuisance odours.
To manage odour, Watercare proposes to monitor the operation of the WWTP in accordance with an Operations Management Plan or Air Quality Management Plan (“OMP” or “AQMP”). The OMP / AQMP will set out methods to minimise the generation of odour and has been described further in Section 6.
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Figure 11: Staged upgrading of the Army Bay WWTP.
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4. EXISITING ENVIRONMENT
4.1 PHYSICAL SETTING
The Army Bay WWTP is located at the tip of the Whangaparaoa Peninsula, approximately 50 km north of the Auckland CBD. It is surrounded by Shakespear Regional Park to the south, and New Zealand Defence Force (“NZDF”) occupied land to the north and east. The Army Bay WWTP is located at approximately 30 m above sea level (“ASL”) in a natural valley that is aligned east-west, with hill slopes rising to 60 m ASL to the north and south. The hill slopes are steep with a slope of approximately 1 in 3 and are generally vegetated with low- lying shrub.
The site is located in the high air quality area under the Unitary Plan and the Auckland Rural Airshed, and is not considered to be polluted under Regulation 17 of the National Environmental Standards for Air Quality (“NESAQ”). However, the Auckland Urban Airshed boundary is located approximately 750 m from the WWTP site and this is defined as being polluted under Regulation 17 of the NESAQ.
The Army Bay WWTP outfall discharges to the Whangaparaoa Passage approximately 1.1 km east of Huaroa Point (Figure 12). The outfall point is located in waters approximately 25 m deep.
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Figure 12: Army Bay WWTP site and the outfall point.
Communities Serviced
The communities currently serviced by the Army Bay WWTP comprise Whangaparaoa, Red Beach, Orewa and Hatfields Beach, Silverdale and Stillwater, and the communities to be connected to over the proposed consent term comprise Waiwera, parts of Wainui, Dairy Flat, Redvale and Okura Bush. Together these communities make up the Hibiscus Coast.
Neighbouring Land Use
The Army Bay WWTP is surrounded by Shakespear Regional Park to its south-east, NZDF occupied land to the north-east, and Army Bay to west.
Shakespear Regional Park is an open sanctuary that provides a pest free habitat and a safe home for wildlife. The park integrates conservation, recreation and farming.
The NZDF site to the north-east of the Army Bay WWTP is designated under the Unitary Plan for Defence Purposes. Approximately 70% of its 157 ha area is SEA. The Army Bay WWTP shares an accessway with this site.
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Meteorological Conditions
The closest meteorological monitoring station to the WWTP is the Whangaparaoa EWS monitoring station, which is located approximately 1.2 km to the east of the site. The monitoring station is located on the summit of a hill towards the eastern end of the peninsula at a terrain elevation of approximately 89 m above sea level.
The wind flows observed at the monitoring station are expected to be broadly indicative of wind flows at the WWTP. However, wind flows at both the monitoring station and WWTP will be influenced by the topography, surrounding each site, such as the channelling effect of nearby hills, observed either side of the WWTP.
Figure 13 shows the distribution of hourly average wind speeds and wind directions observed at the EWS monitoring site for the period January 2009 to December 2012. The average wind speed for the three year period of 2009 - 2012 of 5.4 m/s is comparatively high and is likely to be due to the exposed costal location of the monitoring station on the hill summit. Lower average wind speeds would be expected at the WWTP which is located in a more sheltered gully location.
Note: The label refers to the percentage of hours the wind occurs in each direction.
Figure 13: Wind rose for Whangaparaoa Peninsula (2009-2012).
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4.2 EXISTING WASTEWATER INFRASTRUCTURE
The existing Army Bay SMA wastewater collection system is a fully separated drainage type, and due to the undulating terrain of the catchment, is a highly pumped system with a total of 45 pump stations. The trunk network incorporates three main pump stations (Orewa, Stanmore and Hobbs Bay) and associated rising/gravity mains which progressively pump wastewater 16 km from Orewa along the Whangaparaoa Peninsula to the WWTP.
Conveyance Network
4.2.1.1 Connected Wastewater Network and Transmission Capacities
The Army Bay WWTP wastewater transmission network comprises the following:
• The Orewa to Stanmore pump station and trunk sewer, which has a capacity of 190 L/s;
• The Stanmore to Hobbs pump station and trunk sewer which has a capacity of ~450 L/s
• Hobbs PS to Army Bay WWTP, which has a capacity of ~650 L/s;
• The Wainui tunnel alignment;
• Three trunk pump stations; and
• 42 network pump stations.
4.2.1.2 Works Undertaken
Watercare is constantly seeking to proactively manage their wastewater network to optimise its performance and ensure it does not give rise to any nuisance effects to neighbours. In this regard, provided below is a summary of the work undertaken over the past two years on the Army Bay WWTP network:
• Shakespear carbon filter installation – no odour complaints received since the installation of carbon units;
• Lining of manholes along Alec Craig Way and replacement of lids to remove odour;
• Community liaison with affected the residents of Millwater, Stanmore Bay and Shakespear;
• Installation of carbon unit at Stanmore pump station to allocate odour affecting neighbours; and
• A trial into dosing the wastewater to reduce odour.
4.2.1.3 Programmed Upgrades of the Network
As set out above, Watercare operates four trunk pump stations, and five network pump stations on the Army Bay WWTP system. To service the projected inflows for the system and the Army Bay WWTP, Watercare have programmed the following upgrades for the pump stations and network:
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• Wainui wastewater servicing – 2018 – this is currently being completed as development of Wainui occurs.
• Orewa-West pump stations and associated network upgrade – 2019.
• New Stanmore pump stations rising main and additional storage capacity – 2023.
• Bay Street trunk pump station upgrade – 2030.
• Orewa pump stations and trunk network upgrade – 2032.
With regard to these upgrades, the following assumptions have been made:
• Population figures have been derived from the Auckland Council ART Growth Model v i11 in conjunction with the Auckland Unitary Plan – Operative in part land use zonings;
• Non-residential population densities have been derived using a medium commercial loading rate of 0.7 ls/ha and a peak wet weather flow rate of 1,500 litres/person/day; and
• The rate of non-residential density is the same as residential density increase.
Figure 14 provides a map showing the works and upgrades to occur, and further detail on the work to occur.
The upgrades to the Army Bay WWTP conveyance network are required regardless of whether any new development areas are serviced by the Army Bay WWTP, and as such do not comprise part of the resource consent application. The description here is provided to complete the overall understanding of the Army Bay WWTP network.
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Figure 14: Army Bay WWTP Network Upgrades.
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4.3 CULTURAL SETTING
In preparing the application, Watercare undertook consultation with mana whenua groups in order to understand the cultural landscape in while the Project area is present. Mana whenua who accepted Watercare’s consultation offer were:
• Ngāti Manuhiri;
• Ngāti Whanaunga;
• Te Kawerau a Maki;
• Ngāi Tai; and
• Ngāti Maru.
Of the mana whenua groups identified above, Ngāti Manuhiri and Ngāti Whanaunga chose to undertake cultural values assessments (“CVA”) with regard to the Project. While the CVAs have been provided to Watercare on a confidential basis, both Ngāti Manuhiri and Ngāti Whanaunga have agreed to the general descriptions of their associations with the Project area as described below.
Ngāti Manuhiri
Ngāti Manuhiri identify that they have cultural, ancestral, historic and spiritual association with the entire north-eastern coastline of Auckland, including tributaries and inland catchments. Ngāti Manuhiri occupied strategic places throughout their rohe, both seasonally and/or permanently, particularly adjacent to areas rich with marine resources. Inland areas were also utilised for forest birds, trees, and rongoā. This is evidenced by the multiple identified archaeological sites within their rohe (Figure 15).
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Figure 15: Archaeological sites within the Army Bay WWTP service area.
Ngāti Manuhiri identify the seaway to the north and east of Whangaparaoa Te Moana Nui ō Toi (The Great Sea of Toi), named after Toi Te Huatahi, a famous early Māori ancestor and voyager, to who Ngāti Manuhiri whakapapa. Te Moana Nui ō Toi, and its mauri, kaitiaki, biodiversity, seaways, islands and traditions lie at the heart of Ngāti Manuhiri. Te Moana Nui ō Toi is associated with the arrival of the Tainui and Aotea waka in the regional, and the renowned ancestors Rakataura and Turi, from who Ngāti Manuhiri’s founding ancestor, Manuhiri, descends. Te Moana Nui ō Toi provided a vast source of food to Ngāti Manuhiri over generations.
Ngāti Whanaunga
Ngāti Whanaunga identify that the Army Bay WWTP and its outfall are located within an area that has been occupied by Mana Whenua groups dating back to the arrival of the original waka from Hawaiiki. Accounts explain how the Tamaki Isthmus was used for extensive gardens due to fertile soils, mahinga kai from the harbours and waterways, pā sites on the numerous maunga, and coastal settlements.
Ngāti Whanaunga recognise nine mana whenua principles as follows:
• Kaitiakitanga – responsibilities including a duty to protect and preserve ancestral lands and water, and to hand them on to succeeding generations in a healthy condition.
• Mauri – the vital energy force that gives being and form to all things in the universe providing the interconnection between humans and the environment. A responsibility of tribal kaitiaki is the maintenance of mauri.
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• Tapu – untouchable, sacred and associated with the gods. Linked to a code for social conduct based on keeping safe and avoiding risk relative back to environmental responsibilities.
• Wāhi Tapu – sacred places of great spiritual significance to tangata whenua, requiring that inappropriate activities are not undertaken in their vicinity.
• Rāhui – a closure of a certain area or restriction of the taking of particular resources.
• Mātauranga Māori – māori knowledge, a way of knowing or conceptualising the māori world.
• Taunahanaha – the practice of naming places thereby, over time imbuing the landscape with significance.
• Papakainga – the original home. Ngāti Whanaunga have numerous Papakainga along the coast of Tīkapa Moana and in Tāmaki
• Tauranga Waka – dedicated waka landing places.
4.4 ECOLOGICAL VALUES OF THE WWTP SITE
Introduction
Wildlands Consultants Ltd undertook an assessment of the terrestrial ecological values of the Army Bay WWTP site. This report is appended as Volume 2, Appendix D. The following section provides a description of WWTP site’s ecological values, including the flora, aquatic habitat, and fauna. The overall vegetation ecological values of the site are set out in Figure 17.
Flora / Vegetation – Significant Ecological Areas
The Army Bay WWTP site is located within a located within the predator-proof fence that defines the boundary of the Shakespear Open Sanctuary. The site occupies a broad gully, with the WWTP itself occupying the central gully floor. The majority of the site (~79%) is subject to the SEA_T_6999m overlay, with the exception of the existing footprint of the WWTP and some small margins adjacent to the WWTP footprint. SEA_T_6999m comprises 14 blocks of vegetation. The block located within the WWTP site extends beyond the site boundary, and is approximately 34 ha in area.
SEA_T_4208 also overlays the site along its south-west and north-west margins respectively.
SEA_T_6999m meets the following SEA factors:
2 Threat status and rarity; 3 Diversity; and 4 Stepping-stones, migration pathways and buffers.
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SEA_T_4208 meets factors two and four.
The gully floor and sides comprise the following vegetation types:
• Mānuka forest and scrub; • Machaerina articulate-pōhuehue reedland; • Tī kouka-mānuka-māpou forest; • Pampas – Machaerina articulate • Pampas tussockland; – raupō tussockland; • Exotic grassland; • Ngaio forest; and • Ponga treefernland; • Pampas-māpere tussockland (Figure 16).
Wildland’s survey of the flora on the site recorded 43 species of indigenous plants and 28 species of naturalised plants. Three of these are defined as being ‘at-risk’ or ‘threatened’, being:
• Mānuka – at risk;
• Kānuka – threatened; and
• Pōhutukawa – threatened.
Vegetation on the site is part of a much larger contiguous tract of high quality indigenous vegetation that extends into neighbouring properties. This large area provides a critical stepping stone for fauna species moving between the gulf islands and mainland. Overall, most of the vegetation at the site is of a high ecological value (Figure 17).
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Figure 16: Distribution of vegetation across the site.
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Figure 17: Vegetation ecological values of the site.
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Aquatic Habitat
There is a wetland habitat at the eastern end of the site, in vegetation area seven, which receives water from a permanent stream that flows through the vegetated catchment on the neighbouring site. At the downstream end of the wetland, the stream is piped below the WWTP and discharged at the western boundary with Shakespear Regional Park.
Wetlands are a nationally and regionally uncommon ecosystem type. These afford important ecological services including providing habitat and improving water quality. These areas are considered to be of a high ecological value.
Fauna
4.4.4.1 Avifauna
Eight indigenous bird species were recorded at the site:
• Fantail; • Riroriro / Grey warbler;
• Pūkeko; • Tīeke / North Island saddleback;
• Tūi; • Pied stilt; and
• Silvereye; • Pūtangitangi / paradise shelduck.
Tīeke are classified as ‘at risk – recovering’ and were reintroduced to the Shakespear Open Sanctuary from Tiritiri Matangi Island in May 2018.
Due to the absence of mammalian predators in the Shakespear Open Sanctuary, bird numbers have significantly increased as birds from Tiritiri Matangi become established on the mainland. Those species known to be dispersing from Tiritiri Matangi include korimako / North Island bellbird, kākā, kakariki, and occasionally hihi. Furthermore, 20 little spotted kiwi were released in May 2017, and a further 20 in March 2018. As the WWTP site is located within the sanctuary, comprises potential habitat for these birds.
4.4.4.2 Herpetofauna
No lizards were observed during the survey however, suitable habitat for several indigenous lizard species does occur at the site. Seven species of indigenous lizards have been recorded within the Shakespear Open Sanctuary, including copper skink, ornate skink, shore skink, moko skink, elegant gecko, Pacific gecko and forest gecko.
4.5 ECOLOGICAL VALUES OF THE RECEIVING ENVIRONMENT
Introduction
Aquatic Environmental Sciences (“AES”) undertook an assessment of the ecological values of the treated wastewater receiving environment (“the AES Report”) (Volume 2, Appendix E), which was informed by technical investigations undertaken by Coast & Catchment Ltd,
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DHI Water & Environment, Streamlined Environmental Ltd, and Wildlands Consultants Ltd, which are appended as Volume 2, Appendices F-J.
The following sub-sections provide a description of the existing ecological environment as well as the ecological values of the Whangaparaoa Passage.
Hydrodynamics
The water depth in the Whangaparaoa Passage gradually increases towards the east, reaching approximately 30 m depth 700-800 m from Tiritiri Matangi, before rising sharply towards the island. The water depth at the outfall is approximately 25 m.
Modelling indicates that the constrictions created be the Whangaparaoa Peninsula headland and Tiritiri Matangi generate relatively high current flow through the passage, with the strongest currents associated with ebb flows.
4.5.2.1 Currents
Currents around the Whangaparaoa Peninsula headland, Whangaparaoa Passage, and Tiritiri Matangi are relatively complex, with small residual currents and a dominance of tidal flows. Ebb and flood tide currents are relatively symmetrical within the Whangaparaoa Passage, and to the south of the peninsula (Figure 18 - Figure 20).
Figure 18: Residual currents of the receiving environment.
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Figure 19: Peak ebb (outgoing) tidal velocities of the receiving environment.
Figure 20: Peak flood (incoming) tidal velocities of the receiving environment.
Water Quality
Auckland Council carry out monthly marine water quality monitoring at 31 sites across the region. Along the east coast, six sites have been monitored since the early 1990s however, none are located on the Whangaparaoa Peninsula. The nearest to the receiving environment are at Mahurangi Heads and Orewa to the north, and at Browns Bay to the south.
The current water quality for these sites is ‘excellent’, as has been the case for the past three years.
Water quality monitoring of the Whangaparaoa Passage has not been required under the current consent, as such AES requested samples be taken and compared to the ANZECC guidelines as set out in Table 10.
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Table 10: Water quality monitoring around Whangaparaoa Head.
Date Site Amm-N Nitrate-N TN Chl a
26/4/2018 1 km off Whangaparaoa Head <0.005 <0.002 0.081 0.0009
Near discharge point <0.005 <0.002 0.080 0.0018
1 km off Huaroa Point <0.005 <0.002 0.083 0.0016
16/5/2018 1 km off Whangaparaoa Head 0.021 0.0079 0.10 0.0022
Near discharge point 0.011 0.0073 0.081 0.0017
1 km off Huaroa Point 0.013 0.016 0.083 0.0017
18/9/18 1 km off Whangaparaoa Head <0.005 0.003 0.068 0.0018
Near discharge point 0.016 0.0032 0.06 0.0017
1 km off Huaroa Point 0.011 <0.002 0.057 0.00078
ANECC 2000 0.015 0.015 0.300 0.004 guideline
Sediment Quality
Sediment samples have been collected from four sites in the Whangaparaoa Passage to inform this assessment:
1. Near the outfall; 2. Approximately 1.8 km north of the outfall; 3. Approximately 2.2 km south of the outfall; and 4. Approximately 1.5 km east of the outfall.
Sediments were measured for total metals cadmium, chromium, copper, lead, mercury, nickel and zinc (“Cd, Cr, Cu, Pb, Hg, Ni and Zn”), grain size and total organic carbon.
Auckland Council Environmental Response Criteria (“ERC”) (Auckland Regional Council, 2004) were used for Cu, Pb and as they are more conservative (protective) than ANZECC
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(2000) sediment quality guidelines and provide a traffic light type assessment of water and sediment quality: Green (low risk to the biology so the site is unlikely to be impacted); Amber (medium impacted site, possible impact on biology); Red (high impact site, biology of the site is probably impacted). ANZECC/ARMCANZ recommended Sediment Quality Guideline Values were used for Cd, Cr, Hg and Ni.
Sediment metal concentrations were consistently higher at the north site in comparison to the outfall, south and east sites. This was consistent with relatively elevated mud and TOC at the north site relative to the others. However, all sediment metal concentrations were less than 50% of either ERC-Green or SQGV, suggesting low risk to the biology at all sites.
Microbial Characteristics
4.5.5.1 Pathogens
Historical data (2006-2009) for the receiving marine environment around the outfall indicate that the enterococci concentrations in the receiving water do not exceed the ‘Microbiological Water Quality Guidelines for marine and freshwater recreational areas’ (MfE/MoH, 2003) threshold of 280 CFU/100 mL under dry weather flows and only occasionally under wet weather flows. Above this threshold, water is considered unacceptable for swimming or other forms of contact recreation. For most of the years for which monitoring data was collected for these sites as part of compliance monitoring, median enterococci and E. coli concentrations were not more than 10 CFU/100mL
Annual monitoring between 2010 and 2017 found that faecal indicator bacteria concentrations were generally low (<20 CFU/100 mL) in the receiving environment. On occasion, rainfall of more than 10 mm (in the previous five days) appeared to result in peaks in faecal indicator bacteria concentrations; however apart from one occasion in May 2015 at Te Haruhi Bay, when the E. coli concentration was 600 CFU/100 mL, the concentrations of faecal indicator bacteria remained below the MfE/MoH thresholds. Overall, the microbiological water quality over the period monitored was considered to be very good and compliant with the MfE/MoH guidelines (2003) for contact recreation.
4.5.5.2 Shellfish
Monitoring data from shellfish tissue collected within the receiving environment between 2009 and 2017 indicate that there has been little or no change of any practical significance in ‘average’ E. coli concentrations in shellfish tissue over time.
The New Zealand Microbiological Reference Criteria (FSANZ 2002) provides bacteriological guideline values for shellfish gathering, as follows:
• The median faecal coliform content of samples taken to meet the guideline standards should not exceed 14 per 100 mL, and not more than 10 percent of samples should exceed 43 per 100 mL.
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• The E. coli median MPN of the shellfish samples must not exceed 230 E. coli per 100 g and not more than 10 percent of the samples must exceed an MPN of 700 per 100 g.
Analysis of the shellfish tissue E. coli concentrations shows that this standard was exceeded only on a few occasions, which as shown for water quality, were usually related to increased rainfall in the days preceding sampling. The only exception to this was at Huaroa Point (the site closest to the discharge) in November 2016, when shellfish tissue E. coli levels were well in exceedance of the FSANZ (2002) guidelines with no obvious correlation to rainfall. The proportion of samples exceeding the FSANZ (2002) guidelines for faecal coliform content of shell fish samples collected in the receiving environment was low. At least 92% of the 150 shell fish samples collected from the receiving environment from 2006 until 2017 complied with the FSANZ (2002) guideline.
Emerging Contaminants
Two samples of the Army Bay WWTP discharge were collected and analysed for emerging contaminants. The results of the analysis were compared with the Waiuku and Omaha WWTPs, 13 WWTPs around New Zealand, and WWTPs around the world. Generally, concentrations of emerging contaminates in the Army Bay WWTP discharge were markedly higher than Waiuku and Omaha WWTPs, more in line with concentrations from the 13 WWTPs around New Zealand, but generally lower than WWTPs worldwide (primarily EU and US). Of note:
• The polycyclic musk galaxolide a synthetic fragrance had an average concentration from Army Bay WWTP discharge (1332 ng/L) was well above Waiuku/Omaha (30/60 ng/L), NZ (243 ng/L) and worldwide (850 ng/L). This concentration was approximately half the maximum reported worldwide (2,770 ng/L);
• Five of eight organophosphate flame retardant (TiBP, TBP, TCEP, TCPP, TDCP) average concentrations from the Army Bay WWTP discharge were markedly higher than from Waiuku/Omaha and New Zealand WWTPs, with TCPP and TDCP markedly higher than worldwide average concentrations. In contrast two (TPP and TBEP) were present at lower concentrations in Army Bay WWTP discharge relative to Omaha, New Zealand and worldwide average concentrations;
• Aspirin average concentrations from the Army Bay WWTP discharge (2720 ng/L) was markedly higher than other pharmaceutical concentrations. There was no literature data for comparison with New Zealand or worldwide WWTPs. Salicylic acid (breakdown product of aspirin) was present in low concentrations relative to those reported worldwide, which is possibly a reflection of low WWTP removal efficiency for aspirin from the Army Bay WWTP relative to other WWTPs;
• The carbamazepine (used for treatment of epilepsy and neuropathic pain) average concentration from the Army Bay WWTP discharge (1001 ng/L) was approximately double worldwide average concentration (540 ng/L);
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• Diclofenac and naproxen (non-steroidal anti-inflammatory drugs) average concentrations from Army Bay WWTP discharge (540 and 240 ng/L, respectively) were around the average worldwide WWTP concentrations (454 and 227 ng/L).
The risk of EOCs to the receiving environment is summarised in 5.5.2.2.
Significant Ecological Areas
The ecological values of the environment surrounding the outfall point are identified as being of a high quality. The outfall discharge point itself is not within a SEA however, there are SEAs situated around the end of the Whangaparaoa Peninsula. The outfall pipeline passes through one of these SEAs, the boundary of which extends approximately 400 m from the coastline, with the outfall approximately 600 m from outer edge of the SEA.
The SEAs attributed to the coastline near the outfall include the following:
Whangaparaoa Peninsula, Whangaparaoa Headland cliffs and intertidal platforms
The Whangaparaoa Headland provides a valuable ecological linkage between the Auckland mainland and Tiritiri Matangi Island. Native bird species dispersing from the island include bellbirds, kaka and kakariki. The large, restored freshwater and saline wetlands within Shakespear Regional Park and bays surrounding the headland provide habitat for threatened native birds including spotless crake, fernbird, New Zealand dotterel, white-faced heron and pied stilt. The cliffs and intertidal platforms of the rocky coastline at the end of the Whangaparaoa Peninsula are made up of sedimentary Waitemata Group rocks that were deposited during the Miocene. The rocky shores and the intertidal and subtidal sediments on the southern side of the peninsula offer a complex of habitats for a variety of plant and animal communities. The rocky shores support large populations of reef-fish, kina and other invertebrates, and a rich variety of marine algae. On one part of the shore platform the marine ecosystem grades into a significant area of natural terrestrial vegetation; a small area of complex shrubland on a headland or peninsula. The sediments of the bays on the south of the peninsula is the habitat of extensive beds of molluscs and in the north- eastern corner of Okoromai Bay grade into a saltmarsh which is a significant migration pathway for native freshwater fishes. Remnant coastal forest has been enhanced by restoration plantings within Shakespear Regional Park and large scrubland areas on the headland provide habitat for the threatened Moko and ornate skink. An Open Sanctuary has been created on the Whangaparaoa Headland with the installation of a predator proof fence in 2010.1
Benthic Habitats and Communities
4.5.8.1 Overview
Three benthic habitats have been identified within the vicinity of the outfall:
• Intertidal sandstone reef;
1 Auckland Unitary Plan – Schedule 4 - Significant Ecological Areas – Marine Schedule
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• Subtidal sandstone reef; and
• Subtidal channel.
Each of these is discussed below.
4.5.8.2 Intertidal Habitats
The intertidal community is fairly similar throughout the surveyed area, with the greatest change in species abundance and diversity due to position on the shoreline (tidal zonation).
In the high shore, splash zone sandstone surfaces were predominantly bare, with patches of a moss-like algae present in some places. However, it is noted that there was the presence of barnacles, plicate barnacles, periwinkles and black nerite were scattered over the rocks.
Along the upper shore, patches of coralline turf covered the depressions where water pools. Rock oysters and black nerita were abundant and common, while spotted black top shells, snakeshin chitons, limpets and crabs, were occasionally present. Dense patches of tube worms were occasionally observed.
The mid shore is covered in coralline turf, with patches of Neptune’s necklace and blue green algae present in the depressions where water pooled. Rock oysters and plicate barnacles were abundant on the ridges. Tube worm beds were patchily distributed, Black nerita were abundant, Snakeskin chitons, spotted top shells, oyster borers , black sea slug, horn shells, Codium convolutum, and red-mouthed whelks were all occasionally observed.
The lower shore is almost completely covered in coralline turf and Neptune’s necklace to the south of Whangaparaoa Head and west of Huaroa Point. Rock pools contained a variety of seaweeds. Hermit crabs, glass shrimps, kina, cat’s eyes and triplefins were also present in the rock pools.
Various birds were seen in the intertidal area including red-billed gulls, variable oystercatchers and shags.
4.5.8.3 Subtidal Habitats
The Whangaparaoa Passage contains a heterogenous mix of subtidal habitats, with considerable variation in substrates and associated biota.
The central passage area and north of the outfall contained sediments with little or no visible shell and low habitat complexity. Visible shell content increased, with an associated increase in habitat complexity, towards the shores of Whangaparaoa Head and Huaroa Point west of the outfall, and towards Tiritiri Matangi Island in the east.
Sediments towards the south of the outfall were a mixture of those with and without low levels of visible shell. The areas of highest habitat complexity were associated with areas of shell gravel/hash containing biogenic species. The only reefs encountered within the survey
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area were those along the Whangaparaoa shoreline and the habitats here were also considered to be ‘complex’.
Benthic epifauna were recorded in 45% of drop the camera images, including four species, or species groups, that form sensitive biogenic habitats, as follows:
• Macroalgae (10% of images);
• Horse mussels (5% of images); and
• Various sponges (15% of images);
Scallops were recorded in 4% of images, and scallop shell in 7% of images, generally in water depths of around 25-35 m along the eastern margin of the Whangaparaoa Passage, as well as to the south of the survey area and to the west of the outfall.
4.5.8.4 Shellfish
Shellfish species present in the vicinity of the outfall include scallop beds and green-lipped mussels, and on the western side of the Whangaparaoa Passage scallop beds and green- lipped mussels, New Zealand rock oysters, cat’s eyes, sea urchin, and black nerita.
Coastal Avifauna
The establishment of the Shakespear Open Sanctuary has resulted in a significant increase in bird numbers, with birds from neighbouring Tiritiri Matangi becoming established on the mainland. A total of 72 indigenous bird species have been recorded in the outer Whangaparaoa Peninsula and Whangaparaoa Passage. The area supports at least 14 ‘Threatened’ species, 31 ‘At Risk’ species, and four migratory species.
The wetlands of the Whangaparaoa headland provide habitat for threatened indigenous birds, including spotless crake, fernbird, banded rail, New Zealand dotterel, and Australasian bittern.
The coastline also provides extensive intertidal feeding habitat for wading birds such as pied stilt and oystercatchers. While seabirds such as the grey-faced petrel, Cook’s petrel, and sooty shearwater are frequently seen foraging in the waters of the Whangaparaoa Passage.
Fish
An analysis of data from trawl catches around the inner Hauraki Gulf (including the Peninsula) found the ten most abundant species in shallow waters over muddy substrate, in decreasing order were; yellow-eyed mullet, kahawai, yellow-belly flounder, spotty, snapper, rig, sand flounder, eagle ray, trevally and spotted stargazer.
As discussed in previous sections, the tip of Whangaparaoa Peninsula and Tiritiri Matangi Island are fringed with shallow rocky reefs, and these areas have a moderately high species
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richness of reef fishes. The most common fish observed in these habitats are variable triplefins, spectacled triplefins, parore, leatherjackets, sweep, jack mackerel and goatfish.
The most prevalent demersal fish species caught in trawls around the Whangaparaoa Peninsula were snapper, red gurnard and John dory. The Whangaparaoa Passage also appears to be a moderately important area for snapper reproduction, with a moderate abundance of snapper eggs collected from the passage during egg surveys. The abundance of biogenic habitats in and around the Passage suggests that this area is also likely to be attractive to juvenile snapper.
4.5.10.1 Commercial Fishing
The area around the Whangaparaoa Peninsula is of a low importance for commercial fishing, as trawling and Danish seining are prohibited in this area. Very low levels of commercial longlining do occur, with less than 10 longline sets/3 km2 conducted between 2014 and 2016. Commercial fishers are likely to be mainly targeting snapper, which is the primary fish caught in the inner Hauraki Gulf.
4.5.10.2 Recreational and Customary Fishing
Aerial surveys indicate that the area around the Whangaparaoa Peninsula is subject to relatively low recreational boating pressure, but the area west of Tiritiri Matangi Island is subject to high fishing pressure. The main forms of fishing are likely to be line fishing from boats. Shore based fishing around the peninsula is likely deterred by the prohibition of public access around the coastline of the NZDF land.
The main fish species likely to be targeted by recreational fishers in the vicinity of the outfall are snapper and kahawai. Species such as kingfish, John dory, parore, gurnard, trevally, blue moki, porae and various sharks and rays will potentially be caught by line fishers, but in lower numbers. Reef species, such as red moki, butterfish and silver drummer may also be targeted by fishers and divers using set nets or spears.
There are no rohe moana areas, mātaitai reserves or areas of significant cultural value identified in the Unitary Plan around the Whangaparaoa Peninsula. Tiritiri Matangi Island is, however, of cultural important to iwi, and Te Kawerau a Maki and Ngāti Paoa have traditional guardianship (mana whenua) over the island.
Marine Mammals
The most commonly seen marine mammals in the vicinity of Whangaparaoa Peninsula are common dolphins and Bryde’s whales. However, southern right whales, humpback whales, sei whales, blue whales, beaked whales, bottlenose dolphins and killer whales have also been recorded around the Whangaparaoa region.
Common dolphins are widely distributed, both within New Zealand and internationally, and are thought to live to at least 25 years old. They are present in the Hauraki Gulf year-round,
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moving closer inshore during winter and spring, and further offshore in summer and autumn. In the Hauraki Gulf, pods typically comprise less than 50 individuals, but can reach over 500 dolphins. Common dolphins are opportunistic feeders, feeding on a range of species including arrow squid, jack mackerel, kahawai, yellow-eyed mullet, flying fish, parore and garfish.
Bryde’s whales occur along the entire north-eastern coast of New Zealand from Hauraki Gulf to North Cape but are most common in the Hauraki Gulf where there are about 50–200 resident/semi-resident individuals. They are listed as ‘Nationally Critical’ because of their limited distribution and small population size. Bryde’s whales feed by gulping up large volumes of water along with their prey, which is then filtered through their baleen combs. In New Zealand, potential prey items include krill, saury, anchovy, garfish, jack mackerel, pilchard and sprat.
4.6 LANDSCAPE, AMENITY AND NATURAL CHARACTER VALUES
Under the Unitary Plan the Whangaparaoa Passage, Whangaparaoa Peninsula head and Tiritiri Matangi Island are subject to planning overlays that identify them as having particular landscape, amenity and natural character values. While it is noted that the discharge point is not located in any of these overlays, the following provides outlines those within the vicinity of the outfall.
Outstanding Natural Landscape: Area 50
Coastal Wild nature (Coastal) Wild nature/cultured nature (Lowland) Wild nature/cultured nature (Hill country)
Combination of strongly defined peninsula headland landform and remnant forest intermixed with pasture descending to wetlands and gently shelving coastal margins around Army Bay and Okoromai Bay while the eastern and northern coastlines of the headland are emphatically defined by very steep cliffs and shoals.
Comprises ‘high’ and ‘high/moderate’ natural science factors, aesthetic values, expressiveness and transient values.
Outstanding Natural Landscape: Area 74
Islands Wild nature (coastal) Wild nature/cultured nature (hill country)
Iconic Hauraki Gulf Island landscapes – strongly identified with the Auckland Region as a whole - that include two major volcanic features and other sedimentary island landforms that are highly distinctive and provide the focus for a multitude of views toward the Hauraki Gulf
Comprises ‘high’ and ‘very high’ natural science factors, aesthetic values, expressiveness and transient values.
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Outstanding Natural Feature: Area 224
Tiritiri Matangi Island shore platform
An excellent example of a well- developed shore platform cut in greywacke surrounds most of Tiritiri Matangi.
Outstanding Natural Feature: Area 248
Whangaparaoa Peninsula Waitemata Group deformation
The cliffs and intertidal platforms of the rocky coastline at the end of the Whangaparaoa Peninsula are made up of sedimentary Waitemata Group rocks that were deposited during the Miocene. Together the cliffs and shore platform in the northern part of the area are one of several sites on the Whangaparaoa Peninsula that display a regionally important three dimensional exposure of folds and faults in these rocks. The shore platform is extensive and is considered to be a landform of regional geological importance. Whangaparaoa Head has two significant geological features, a vertically tilted strata and an area of Parnell Grit with huge blocks of displaced basalt forming the point east of Army Bay.
High Natural Character: Area 88
Shakespear Regional Park
An extensive unit comprising headlands, steep cliffs and rocky shoals with sheltered bays and beaches. The coastal edge is extensively vegetated in mature and remnant coastal forest with the hinterlands being a mix of pasture, regenerating scrublands and remnant coastal forest. This natural character unit enjoys a dynamic interaction with the open waters of the Hauraki Gulf, forming the terminus of the Whangaparaoa Peninsula, and gesturing at the historic connection between the main land and Tiritiri Matangi Island. Although nearby, the Army Bay sewage treatment plant and army barracks are slightly removed from the coastal environment, and by in large the unit is free of development. That said, the regional park does inject a large number of visitors to the area in general, but particularly to Te Haruhi, Okoromai and Army Bays where some ancillary structures have been located to service the concentration of visitors.
With regard to High Natural Character: Area 88, it is noted that the Army Bay WWTP is recognised within the description of the area, and can therefore be accepted as part of the high natural character area.
High Natural Character: Area 97
Tiritiri Matangi Island
An extensive unit comprising craggy headlands, sedimentary escarpments and sheer cliffs, rocky shoals, exposed ocean beaches and craggy bays, with some sheltered bays and beaches on the western side of the island. The majority of the island is extensively vegetated in areas of remnant and regenerating forest cover, with development and vegetation clearance, limited to the south of Chinaman Bay. The patterns of vegetation connect vast assemblages of coastal vegetation, descending from mature inland forests to the beachfront species that cling to the exposed eastern beaches and headlands. As such, this coastal
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environment directly engages with, and is a product of, the interplay between its elevated landforms and the open, and sometimes violent, waters of the Hauraki Gulf.
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5. ASSESSMENT OF EFFECTS
5.1 INTRODUCTION
Along with the description of the existing environment, the AES report also provides an assessment of the actual and potential environmental effects that may result from the discharge of treated wastewater to the Whangaparaoa Passage.
The discharge quality parameters and loads to which the effects assessment has been undertaken are as set out in Table 11 - Table 13 which are taken from Tables 5-1, 5-2 and 5- 3 of the AES Report.
It should be noted that the AES Report uses scenarios against which the effects have been considered, which is a different approach to the stages described in the CH2M Beca Technical Report that has informed Section 3 of this AEE. Scenarios 1 and 2 were based on flow volume estimates from previous Auckland Council population growth forecast number than those used in the proposed staged upgrades described in Section 3.4 thus explaining why there are some inconsistencies in the numbers.
Further, it should be noted that Scenario 3 used a 190,000 PE figure to ensure that the assessment of effects at the final stage was representative of a population greater than that which the Auckland Council growth forecasts provided. This has resulted in the effects conclusions to be conservative in comparison to those that would be experienced under the actual forecasted population figures of 188,500 PE.
Finally, the Scenario 3 will only realistically be reached at the end of the proposed 35 year consent term therefore, the output of the AES assessment further represents a conservative effects conclusions which will only likely to be experienced to the full extent towards the end of the proposed consent term.
Table 11: Parameters for scenarios considered for the assessment of ecological effects.
2018 ~2031 ~2041 ~2053
Existing Scenario 1 Scenario 2 Scenario 3
Average Dry Weather 12,960 21,600 30,240 42,336 Flow (ADWF) m3/d
Peak Dry Weather Flow 39,825 65,475 91,800 127,238 (PDWF) m3/d
Peak Wet Weather Flow 53,100 87,300 122,400 169,650 (PWWF) L/s 615 1,010 1,417 1,964
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Table 12: Predicted loads for population scenarios considered.
Parameter Median 2018 ~2031 ~2041 ~2053 Concentration Existing Scenario 1 Scenario 2 Scenario 3
cBOD5 (t/yr) 5 12 40 56 77
TSS (t/y) 5 31 40 56 77
Ammoniacal 5 12 40 56 77 Nitrogen (t/yr)
Total Nitrogen 10 53 96 112 155 (t/yr)
Table 13: Proposed Final Army Bay WWTP wastewater quality standards.
Parameter Units Existing Consent Stage 1 – Serviced Stage 2 - Serviced PE Stage 3 - Serviced PE (Retained until PE ~60,000 – ~100,000 – 140,000 ~140,000 – 188,500 Stage 1 operational 100,00 ~ 5 years)
Median 92 %ile Median 92 %ile Median 92 %ile Median 92 %ile
3 cBOD5 g O2/m 20 35 5 20 5 20 5 20
TSS g/m3 35 75 15 30 15 30 5 20
3 NH4-N g N/m 15 N/A 5 15 5 15 5 15
Total N g N/m3 N/A N/A 15 30 10 20 10 20
E. Coli cfu/100 N/A N/A 10 150 10 150 10 150 mL
Enterococ cfu/100 100 1000 10 150 10 150 10 150 ci mL
Sections 5.4 - 5.9 provide a high-level summary of the findings of the AES report with regard to effects on the receiving environment of the discharge of wastewater from the Army Bay WWTP at Scenario 3 (Table 11 and Table 12), as the ‘maximum’ population scenario, and the discharge quality limits set out in Table 13.
C2HM Beca’s Technical Odour Assessment (Volume 2, Appendix K) assesses the potential effects of odour discharged from the WWTP and is summarised in Section 5.10.
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Finally, Wildlands’ assessment of the ecological values of the WWTP (Volume 2, Appendix D) assesses the effects of the SEA vegetation clearance and land disturbance associated with the WWTP upgrade works and is summarised in Section 5.11.
5.2 POSITIVE EFFECTS
As outlined in Section 1.1, the communities of Whangaparaoa, Orewa, Silverdale, Hatfields, Wainui, Dairy Flat, Stillwater, Okura Bush and Redvale are identified as being subject to significant population growth as the Auckland region continues to expand to the outer areas. When considering the forecasted growth, the existing Army Bay WWTP does not have the sufficient capacity to treat increased amounts of wastewater associated with increased population beyond approximately 2021, nor are there any suitably located alternative WWTPs available to provide for the servicing needs of these communities.
The discharge of treated wastewater from the Army Bay WWTP to the Whangaparaoa Passage will secure the immediate and long-term future of wastewater management for these communities, which are projected to grow to a population of ~188,500 over the lifetime of the consents applied for here. The consenting of the discharges will enable the ongoing operation of the Army Bay WWTP, thus resulting in the continued positive social, public health, environmental and economic benefits for these communities.
Watercare propose a staged approach to implementing upgrades at the Army Bay WWTP, which will be undertaken in line with population growth in the service area. The proposed discharge parameters provide for an improvement in the maximum load of nutrients discharged from the Army Bay WWTP in the short-term and the discharge quality will also improve in the long-term as the upgrades are implemented.
Due to the upgrades proposed for the WWTP, outlined in Section 3.4.4, the discharge quality will be improved, which is reflected in the proposed discharge parameters of the resource consent. Finally, while outside the scope of this consent application, when considering Watercare’s planned network improvements in conjunction with the Army Bay WWTP upgrades, the potential for overflows and adverse effects from the transmission network will decrease, resulting in an overall positive effect for the Whangaparaoa Peninsula.
5.3 EFFECTS ON CULTURAL VALUES
As a result of their extensive involvement in the Process, Watercare understands that Te Kawerau and Ngāti Manuhiri have, in principle, provided their support for the Project.
Further, based on discussions with iwi as part of the Process (see Section 2 and Section 7.2), Watercare understand that Project specific Cultural Impact Assessments (“CIA”) will not be provided.
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Overall, based on the feedback received from mana whenua who have chosen to be involved in the Project to date, Watercare understand that that the effects of the Project on cultural values will be minimised to the greatest extent practicable for the following reasons:
• There will be an improvement in the discharge quality over time as a result of the proposed WWTP upgrades;
• The discharge is occurring from an existing outfall structure;
• The enabling works for the WWTP upgrades at the site have the smallest available footprint within the surrounding SEA; and
• Watercare’s ongoing commitment to continue to engage with mana whenua parties.
It is also noted that Watercare notified those parties who currently have active customary marine title applications under the Marine and Coastal Area (Takutai Moana) Act 2011 of the application. This process and the feedback received has been summarised in Section 7 below.
5.4 HYDRODYNAMIC MODELLING AND SALINITY
To understand the potential impacts of the discharge of treated wastewater, it is necessary to understand the effect of dispersal and dilution on the discharges within the receiving environments. These effects were identified through hydrodynamic modelling of the Whangaparaoa Passage.
Potential effects on the hydrodynamics of the receiving waters include the impact of salinity, as the majority of biota have a salinity tolerance range, and the effects of dilution and mixing processes directly influences this. Furthermore, the intrusion of freshwater can form a layer of lower salinity water over seawater, which can result in a stratification of the water column.
Currently, the discharge does not result in any effects with regard to salinity. The maximum modelled salinity is 0.24 PSU, occurring directly over the outfall. The mean change in salinity (averaged over all states of tide and wind conditions) over the outfall even with the future discharge under Scenario 3 is less than 0.02 PSU. The area where the average change in salinity is more than 0.01 PSU extends approximately 2 km south of the outfall and 3 km north of the outfall.
AES conclude that the modelled increases in salinity will not cause any change in the salinity of the receiving environment, which has a salinity of 32 – 36 PSU due to the Whangaparaoa Passage’s strong currents, resulting in a dynamic and highly dispersive environment, and rapid dilution of the discharge.
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5.5 COASTAL WATER QUALITY
Dilution
The amount of dilution of the discharged wastewater is critical to the impact of the discharge on the receiving environment. Table 14 sets out the levels of dilution predicted at the outfall, and 50 and 100 m from the discharge point for Scenario 3 (which represents the maximum flow scenario). Using these values, the effects on coastal water quality have been assessed.
Table 14: Percentile of dilution over the outfall, 50 m from the outfall, and 100 m from the outfall.
Percentile Dilution over the Dilution 50 m from the Dilution 100 m from the outfall outfall outfall
5 71 164 363
10 98 207 506
20 153 292 689
30 210 378 847
40 261 462 1030
50 314 549 1262
60 366 643 1580
70 419 766 2439
80 479 975 4887
90 556 1275 7896
Nutrients
For all flow volumes set out in Table 11, nitrogen and phosphorus concentrations in the receiving waters were rapidly diluted to background levels within a few metres of the discharge point. At the outfall itself, 95% of the time dilution of 70 times occurs, and 360 times within 10s of metres from the outfall.
Using the proposed discharge median of <10 mg TN/L, dilution would need to be 1,000 times to reduce concentrations to background levels of <0.010 mg/L. This level of dilution would occur at the 50th percentile within 100 m of the discharge.
Standards utilised to classify coastal water quality include the ANZECC (2000) guidelines, the pilot Estuary National Objectives Framework (which have been developed but are not yet published), and Auckland Council’s own classification system.
The ANZECC (2000) guidelines are most commonly used in New Zealand but are generally considered to be too conservative for New Zealand environments. The Auckland Council
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classification system uses an index representing the deviation from “natural” conditions. As set out in Section 4, the level of nutrients measured off Orewa and Browns Bay are classified as “excellent” under this system. AES consider that with the proposed improvement in concentrations of most parameters of the Army Bay WWTP discharge the water quality at these sites would remain “excellent”. In the case of TSS and TN, levels will be reduced resulting in an improvement in discharge quality, and be indistinguishable from background levels.
Modelling has shown that the immediate dilution will be at least 500 times for 90% of the time within 100 m of the outfall, this results in a reduction of the nutrient concentrations below:
• TN to below <0.02 mg/L and 92nd percentile levels to below 0.04 mg/L;
• Ammonia-N to <0.01 mg/L and 92nd percentile levels to below 0.03 mg/L; and
• Biochemical oxygen demand to <0.02 mg/L under the 50th percentile dilution prediction for the 92nd percentile limit
With regard to nutrient loads, despite the improvement in the discharge concentrations, loads will increase over time as population increases due to increased inflow into the WWTP. The current TN load is 53 tonnes/year (“t/yr”), and is predicted to increase as follows:
• Scenario 1 – approximately 2031 – TN = 96 t/yr;
• Scenario 2 – approximately 2041 – TN = 112 t/yr; and
• Scenario 3 – approximately 2053 – TN = 155 t/yr.
AES do not anticipate that these loads will result in a change in the overall water quality status or increased risk of algal blooms, even when considered cumulatively with the Snells Beach and Rosedale WWTPs. Furthermore, AES note that the TN load at the end of Scenario 3 (~2053) would comprise <1% of the total Hauraki Gulf annual total TN load.
5.5.2.1 Phytoplankton
Phytoplankton are controlled by a number of factors including light availability, flushing rate, supply of macronutrients (nitrogen and phosphorus), and micronutrients (such as silica and iron), and grazing pressure by benthic and pelagic species. Nutrient availability is considered to be the major factor leading to enrichment and increased growth of nuisance macroalgae and phytoplankton in coastal systems like the receiving environment with nitrogen being the limiting nutrient in New Zealand coastal waters.
As set out above, despite the total nutrient loads increasing over time as population increases, AES do not anticipate that there will be any discernible change in the nutrient concentrations therefore, the additional loads as a result of the discharge will not directly result in a change in trophic status or the increased risk of nuisance macroalgae and phytoplankton blooms.
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5.5.2.2 Rick of Emerging Contaminants in the Water Column
AES anticipate that the concentration of emerging contaminants in the discharge will be the same as they are currently, with a corresponding increase in flows. Currently, of the emerging contaminants measured, 22 emerging contaminants are present in the discharge, at less than 10% of the applicable guideline, six are present at between 10 and 99%, seven are present at or above the applicable guideline, and three have no guideline to compare to.
Those emerging contaminants above their applicable guidelines were between 100% of the guideline and 1158% of the guideline. The concentration of β-estradiol, which was 1158% of the guideline, suggests that the minimum dilution needed to reduce emerging contaminates below the applicable guideline is 12 times. The minimum (5th percentile) dilution over the outfall under Scenario 3 will be 71 times, while the median (50th percentile) is 314 times. Therefore, the risks from emerging contaminants in the discharge are very low and are not considered to result in any adverse effects in the receiving environment.
5.5.2.3 Summary of Effects on Water Quality
The concentrations of TN and TSS will decrease as a result of the staged WWTP upgrades however, ammonia-N and nitrate-N will not change. Therefore, AES consider that there will be no increased risk of eutrophication, nuisance phytoplankton, or macroalgal blooms.
Levels of ammonia-N and nitrate-N in the discharge are well below those that would cause toxicity in marine biota, while metals and emerging contaminants will be rapidly diluted to levels below the accepted guidelines.
Overall, due to the dynamic and dispersive receiving environment, AES expect that the “excellent” quality of the receiving environment will be maintained despite TN and phosphorus loads increasing over time.
5.6 EFFECTS OF MICROBIAL CONTAMINANTS
Pathogens in wastewater influents include protozoans, viruses and bacteria, which affect the digestive system, and can present a serious health risk if ingested, in particular through the consumption of shellfish. The Army Bay WWTP was upgraded in 2006 to improve the UV treatment system, and the discharge now has comparatively low levels of enterococci and faecal coliforms such that microbial contaminants and viral concentrations are in the range reported for other WWTPs. Despite this, some pathogens potentially survive the treatment process and present a risk for recreation and shellfish consumption
As such, a quantitative microbial risk assessment (“QMRA”) has been carried out for enterovirus, adenovirus, and norovirus using a typical range of influent values, and calculating the likely wastewater effluent concentrations as a consequence of different treatment levels, being:
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1. No treatment – a complete failure of the WWTP; 2. Two log reduction – 100 fold removal; 3. Three log reduction – 1,000 fold removal; and 4. Four log reduction – 10,000 fold removal.
The QMRA was undertaken for five sites within the receiving environment (site numbers 1, 2, 5, 6 and 7, in Figure 21) and undertaken for five scenarios, being:
1. A baseline case; 2. A population equivalent of 116,000; 3. A population equivalent of 160,000; 4. A population equivalent of 192,000; and 5. A population equivalent of 192,000 and extreme peak wet weather flows.
It is noted that these population equivalents are greater than the scenarios used for the rest of this AEE, and are therefore the QMRA outputs are conservative.
Figure 21: QMRA sites.
Results of the QMRA indicate the following:
• Risks increase with increased population and wastewater flows;
• Risks during winter are generally higher than risks during summer due to increased potential for UV based inactivation in summer months;
• Recreational health risks under the four treatment levels at all five sites are as follows:
• No treatment – high risk, with levels often exceeding the “no observable effects level” of 1% for enterovirus, adenovirus and norovirus;
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• Two log treatment – low risk, and always below a “no observable effects level” of 1% when there was a 100-fold removal of enterovirus, adenovirus and norovirus at the Army Bay WWTP prior to discharge;
• Three log treatment – very low risk, and always fell below a “no observable effects level” of 1% when there was 1,000-fold removal of enterovirus, adenovirus and norovirus at the Army Bay WWTP prior to discharge; and
• Four log treatment – practically zero and always fell below a “no observable effects level” of 1% when there was 10,000-fold removal of enterovirus, adenovirus and norovirus at the Army Bay WWTP prior to discharge.
• The risks associated with the consumption of raw shellfish harvested at the five sites under the four treatment levels are as follows:
• No treatment – high risk and often exceeded the “no observable effects level” of 3% for enterovirus and norovirus;
• Two log treatment – reasonably high, i.e. >2.0, although the predicted recreational health risks was still below the 3% threshold when there was a 100-fold removal of enterovirus and norovirus at the Army Bay WWTP prior to discharge;
• Three log treatment – low, and always fell below a “no observable effects level” of 3% when there was a 1,000-fold removal of enterovirus and norovirus at the Army Bay WWTP prior to discharge; and
• Four log treatment – practically zero and always fell below a “no observable effects level” of 3% when there was a 1000-fold removal of enterovirus and norovirus at the Army Bay WWTP prior to discharge.
• Analysis for high levels of consumption of shellfish (up to 800 g/day) showed that at this level and with peak flows three log reductions would be required for Scenario 3 to reduce risks to acceptable levels.
In summary, due to the very high dilution levels, two log removal is sufficient to reduce the risk of illness to swimmers to negligible levels, while three log removal will reduce the risk to those consuming raw shellfish from around the discharge to negligible and acceptable levels.
5.7 EFFECTS ON BENTHIC HABITATS AND BIOLOGICAL COMMUNITIES
Benthic habitats and biological communities could be affected by the discharge through a potentially increased risk of toxic effects, organic enrichment of sediments, or eutrophication. The risk of each of these is assessed below.
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Toxicity
Key heavy metals with the potential to adversely affect benthic species are arsenic (“As”), cadmium (“Cd”), chromium (“Cr”), copper (“Cu”), mercury (“Hg”), lead (“Pb”), nickel (“Ni”) and zinc (“Zn”).
Currently the only metals exceeding the ANZECC 95% marine trigger value are Cu and Zn. To reduce these to below trigger values, Cu requires two fold dilution, and Zn requires three fold dilution.
These levels of dilution will be comfortably achieved in the immediate vicinity of the outfall under Scenario 3, and therefore as there will be little change in the concentration of these metals in the discharge, AES consider the toxicity effects on benthic habitats and biological communities will be negligible.
Organic Enrichment of Sediments
Increases in organic matter can result in deoxygenation of sediments and hydrogen sulphide build up however, this is unlikely under any of the scenarios due to the following:
• Sediments around the existing discharge were found to have a similar total organic matter concentration to three reference sites, and lower total organic carbon concentrations than two of the three reference sites; and
• Improvements to the treatment process are expected to reduce loads of TSS and particulate organic matter.
Nutrient Enrichment Effects on the Benthic Environment
The effects of nutrient enrichment on the benthic environment manifest themselves through increases in algal productivity, which if significant can decrease water clarity, effect dissolved oxygen concentrations, enrich sediments through increased organic loads, and change biochemical processes, which can all lead to alterations in the structure and functioning of benthic communities and habitats. Associated benthic effects can include:
• the promotion of nuisance macroalgal blooms;
• effects on subtidal seagrass and macroalgal beds if an increase in phytoplankton productivity reduces water clarity; and
• the alteration of benthic infaunal communities due to nutrient-driven organic enrichment, including reductions in species richness and diversity.
Results from monitoring at Auckland Council’s east coast sites from 2009-2016 show there is no relationship between instantaneous measurements of TN and total inorganic nitrogen concentrations up to 0.16 and 0.12 mg/L respectively, and chlorophyll a concentrations (a proxy for phytoplankton productivity). Therefore, while nutrient loads will increase as
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population increases, nutrient concentrations in the receiving environment are unlikely to change to the point where a measurable effect in phytoplankton productivity occurs.
5.8 EFFECTS ON FISH AND MARINE MAMMAL
The discharge of wastewater to the marine environment has the potential to effect fish and marine mammals by:
• Reducing dissolved oxygen concentrations through the effects of oxygen demanding substances and eutrophication;
• Reducing water clarity by promoting phytoplankton productivity and increasing suspended solids concentrations; and/or
• Introducing toxic contaminants into the receiving environment.
Each of these is discussed below.
Dissolved Oxygen
Median dissolved oxygen levels in the discharge are predicted to be similar to the current levels under all future scenarios (3.5 mg/L). Once discharged to the receiving environment, mixing will quickly increase dissolved oxygen concentrations in the discharged wastewater, with the 40th percentile dilution for Scenario 3 exceeding 1000 times within 100 m of the outfall. Using this dilution and the average minimum concentration reported at Auckland Council’s east coast monitoring sites between Mahurangi Heads and Browns Bay in 2015 (6.8 mg/L), dissolved oxygen concentrations beyond the mixing zone will be at least 6.8 mg/L for all scenarios. This is considered to be ecologically indistinguishable from ambient concentrations.
Furthermore, recommended BOD limits for the treated discharge are lower than the current limits and BOD effects are likely to be within the range of natural daily variability. Consequently, effects in relation to dissolved oxygen are not expected to extend beyond the mixing zone.
Changes in Water Clarity and Suspended Solids
Changes in water clarity can occur due to increased suspended solids in the water column. Information on the effects of this on fish species is limited to snapper, which are visual feeders and small juveniles require good water clarity to feed on pelagic prey.
TSS concentrations of 32 mg/L were found to cause a ≤20% mortality in snapper larvae after 12 hours, concentrations of 157 mg/L were found to cause ≤50% mortality, and concentrations of >23 mg/L were correlated with a higher level of gill deformation. Turbidity was also found to affect feeding choices of snapper, as they would primarily consume pelagic prey in clear estuaries, but primarily consume benthic prey in estuaries with total suspended solid concentrations of more than 23 mg/L.
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At the outfall, TSS concentrations will be <0.1 mg/L, therefore the effects of changes in water clarity and suspended solids will be negligible.
Toxicity
The key heavy metals with the potential to adversely affect fish and marine mammals are considered to be As, Cd, Cr, Cu, Hg, Pb, Ni, and Zn. As set out in Section 5.7.1, the only metals exceeding the ANZECC marine trigger values in the current discharge are Cu and Zn. While these two metals are essential for fish and marine mammals, they are toxic at high concentrations as they can accumulate in marine mammals with concentrations increasing with age.
Existing copper concentrations in the discharge require around 2-fold dilution, and existing zinc concentrations require around 3-fold dilution to fall below their respective ANZECC (2000) guidelines. This dilution level is predicted to be achieved in the immediate vicinity of the outfall with levels for 95% of the time being at least 70 times at the discharge point. Therefore, the effects of discharged metals on fish and mammals are considered to be negligible.
The ANZECC 95% toxicity guideline for Ammonia-N in slightly to moderately disturbed systems is 0.91 mg/L, which is well above concentrations in the proposed discharge in the near-field after immediate dilution (as is the 99% guideline value of 0.5 mg/L. The effects of ammonia-N will therefore be negligible.
Overall, given the relatively low concentration of nutrients and contaminants in the treated wastewater, and the rapid dilution of the discharge, the effects of the discharge on fish and marine mammals are considered to be negligible.
5.9 EFFECTS ON BIRDLIFE AS A RESULT OF DISCHARGE ACTIVITIES
Effects on birdlife due to the proposed discharge of wastewater are linked to the benthic invertebrates, macroalgal community and fish community that birds feed on. This prey can be impacted through the bioaccumulation of contaminants, including pathogens and heavy metals.
Heavy metals will be rapidly diluted to well below ANZECC (2000) guidelines beyond the outfall, and faecal coliform levels in the discharge are low, often below detection levels. As outlined in the preceding sections, effects on benthic invertebrates, macroalgal community and fish communities are expected to be negligible, therefore AES do not anticipate there being any flow on effects to birdlife.
5.10 EFFECTS OF ODOUR
To inform the assessment of effects on odour from the Project, Watercare engaged CH2M Beca to prepare a ‘Technical Odour Assessment’ of the upgraded WWTP (Volume 2, Appendix K).
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Under normal operating conditions, the processes at the upgraded plant with a high odour potential are expected to be:
• WAS and TWAS storage tanks;
• Solids handling and dewatering facility; and
• Inlet screening works.
To manage the emission of odour from these processes, the inlet screening works will be enclosed and solids handling and dewatering processes will be in an enclosed building. The treatment processes and the building space will be force ventilated to the atmosphere through biofilters. While the WAS and TWAS tanks will also be enclosed and force ventilated through biofilters.
To assess the effects of odour, the following must be considered:
• The sensitivity of the receiving environment;
• Consideration of separation distances and meteorological influences on pollutant dispersion;
• A review of the odour complaint register; and
• The strength and character of the odour emitted from the WWTP and the odour control methods.
In the vicinity of the WWTP, the following high sensitivity receptors have been identified:
• Okoromai Bay picnic area;
• Okoromai Bay Homestead;
• YMCA Shakespear Lodge;
• Te Haruhi Bay campground;
• Te Haruhi Bay beach and picnic area;
• The NZDF building complex; and
• Whangaparaoa residential areas to the west of the site.
Separation distances to, and the sensitivity of these receptors are set out in Table 15.
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Table 15: Separation distances to high sensitivity receptors.
Receptor Odour Sensitivity Minimum Separation Distance
Okoromai Bay picnic area High (daytime) 820 m Low (night-time)
Okoromai Bay Homestead High 1640 m
YMCA Shakespear Lodge High 1410 m
Te Haruhi Bay campground High 1700 m
Te Haruhi Bay beach and picnic area High (daytime) 1520 m Low (night-time)
NZDF building complex High 660 m
Whangaparaoa residential areas High 810 m
Waterfall Gully Track Moderate (daytime) 300 m Low (night-time)
Carparks (two carparks) at the Moderate (daytime) 290m & 390m entrance to the Shakespear Regional Low (night-time) Park
Based on the expected low odour emissions from the WWTP due to the management measures set out above, the separation distances between the WWTP and high sensitivity receptors, the channelling effect of the intervening hills on wind flows, and the low occupancy of these areas, the risk of people using the walking track and carparks being exposed to adverse odour is considered to be low.
5.11 EFFECTS OF THE WWTP UPGRADE WORKS ON ECOLOGICAL VALUES
To enable the proposed WWTP upgrades to occur, up to 4,000 m2 of the surrounding vegetation requires removal. This will occur in two areas, comprising approximately 2,000 m2 per area, with approximately 2,185 m2 of the works to occur within the SEA overlay as shown in Figure 22.
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Figure 22: Vegetation clearance required to upgrade the WWTP.
Wildlands were commissioned to undertake an ecological assessment of the WWTP site, and the effects of the vegetation clearance and land disturbance to upgrade the WWTP, as outlined in Section 3. The vegetation clearance required for the upgrade has the potential to give rise to effects with regard to:
• The loss of vegetation;
• Effects on avifauna;
• Injury to and/or mortality of indigenous fauna; and
• Effects on stream habitat.
Each of these is assessed in the subsections below.
Loss of Vegetation
As outlined above, up to 4,000 m2 of vegetation requires removal to upgrade the WWTP with approximately 2,185 m2 located within the SEA overlay.
Of the 4,000 m2 ~2,770m2 (of which ~1,920 m2 is classified as SEA) contains either exotic grassland or pampas tussockland, and while these species offer good habitat for indigenous skinks they are of low botanical value. Pampas and kikuyu are both classified as ‘Surveillance’ pest plants under the Regional Pest Management Strategy (Auckland Regional Council 2007). As such, Wildlands do not consider it necessary to provide mitigation for the loss of these vegetation types.
The maximum clearance footprint contains ~1,197 m2 of ngaio forest and ~33 m2 of mānuka scrub. All of the mānuka scrub and ~230 m2 of the ngaio forest within the clearance footprint
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also falls within the SEA overlay, resulting in ~263m2 of indigenous vegetation clearance within the SEA overlay. Overall, the maximum area of indigenous vegetation that may be removed is ~1,230 m2 over the entire WWTP site is.
Overall, the vegetation proposed for removal represents a very small proportion (~1.5%) of the overall SEA at the WWTP site and the works footprint area has also been carefully selected to minimise SEA clearance and to include areas of lowest ecological value.
To offset this loss of vegetation, both within the SEA and the other areas, Watercare proposes to plant ~4,242 m2 in accordance with an Ecological Management Plan (refer to Section 6.2.1). The Wildlands SEA report states that this planting would represent a mitigation ratio of approximately 1:3.4. As there is no standard guideline available that prescribes the quantum of mitigation required for a given area of vegetation loss, each site must be assessed on its own merits. Factors that are taken into account include the age and ecological values of the vegetation to be removed, and the potential ecological benefits provided by the planting.
In this case most of the vegetation proposed for removal was originally planted as a shelter belt and includes exotic species and several planted ngaio that are in decline. The additional buffering effect and habitat provided by the proposed planting areas will result in a net ecological gain at the site. As such, Wildlands consider the proposed mitigation ratio is appropriate.
Further to the proposed planting, Wildlands also recommends that any woody vegetation that is cleared should be retained on site in areas outside of the construction footprint to provide habitat for indigenous fauna. Woody debris plays an important ecological role in ecosystems by providing habitat for a wide range of biota.
Overall, this planting will result in a net increase in the availability of high value habitat within the WWTP site, therefore resulting in an overall ecological improvement within the wider SEA, which extends beyond the WWTP into the Shakespear Regional Park and wider Whangaparaoa Peninsula headland.
Adverse Effects on Avifauna
Noise and movement in association with vegetation clearance and land disturbance have the potential to temporarily disturb or displace bird species, which needed to be considered particularly in light of the site’s potential to provide habitat for ‘threatened’ species.
Wildlands do not consider the presence of ‘threatened’ species within the clearance footprint can be ruled out, as such an Avifauna Management Plan will be prepared and implemented in consultation with staff from the Shakespear Open Sanctuary. The content of the Avifauna Management Plan is outlined in Section 6.2.2.
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Effects on Indigenous Lizards
The clearance of vegetation will result in the loss of habitat suitable for indigenous lizards, and could result in injury to and/or mortality of individuals.
To mitigate this, a Lizard Management Plan (“LMP”) will be prepared and implemented prior to the commencement of works. The LMP will guide works to capture indigenous lizards and relocated them to other suitable habitat on the site, and is outlined in Section 6.2.1.
Sedimentation and Contamination of Aquatic Receiving Environments
Land disturbance associated with the upgrade of the WWTP has the potential to result in a sediment discharge into downstream environments. Soils at the site are predominantly clays, which are easily mobilised during rain events.
To avoid potential effects, an Erosion and Sediment Control Plan prepared in accordance with GD2016/005 - Erosion and Sediment Control Guide for Land Disturbing activities in the Auckland Region’ will be prepared and implemented prior to clearance and disturbance activities commence.
Summary of Effects of the WWTP Upgrade Works
Overall, subject to the proposed mitigation planting, the retention of woody debris and the implementation of the various management plans, it is considered the effects the vegetation clearance and disturbance will be avoided or mitigated. Additionally, the provision of the planting within low value areas at the WWTP, including within the surrounding SEA, will have a net-positive effect on the ecological values at the WWTP site and in the SEA.
5.12 OVERALL CONCLUSION OF THE EFFECTS OF THE WWTP DISCHARGES
With regard to the overall effect’s conclusions relating to discharge of treated wastewater to the coastal environment from the staged upgrade of the Army Bay WWTP, the following conclusions are particularly relevant:
• The Whangaparaoa Passage has strong currents, is dynamic and highly dispersive with rapid dilution at the site of the proposed discharge;
• Proposed improvements to the WWTP will lead to reduced discharge concentrations (including nutrients, pathogens, heavy metals and emerging contaminants) which ensures, as a minimum, that the discharge maintains the water quality of the receiving coastal waters of the CMA off the Whangaparaoa Peninsula;
• Improvements to the treatment of wastewater will lead to improved water quality in the discharge which combined with the rapid dilution and dispersion at this site means there will not be any detectable or ecologically significant change in the receiving environment including trophic state, risk of algal blooms, and there would be no effects on fish resources, mammals or birds.
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• The levels of NH4-N and nitrate-N are well below levels that would cause toxicity to marine biota and emerging contaminants and metals would be rapidly diluted to levels below accepted guidelines;
• There will be a small improvement in the quality of the discharge for TN and TSS at each of the short to medium upgrade steps and then a significant improvement when the population reaches 100,000 and 140,000 respectively;
• The proposed discharges will not result in any change to the salinity of the receiving environment;
• Based on the improved discharge quality and the dilution of the receiving environment, any effects associated with the discharges on the benthic environment are expected to be negligible;
• With regard to nutrient loads, the increased loads as a result of the discharges under Scenario 3 will not result in any adverse effects, nor significant cumulative effects, due the small percentage of the TN inputs into the Hauraki Gulf catchment;
• Due to the high dilution and proposed 3-Log treatment, any microbial effects (health risks) associated with contact recreation and shellfish consumption are considered to be at negligible levels;
• Given the relatively low concentration of nutrients and contaminants in the treated wastewater, and the rapid dilution of the discharge, the effects of the discharge on fish and marine mammals are considered to be negligible;
• Changes to the benthic fauna that provides the food resource for fish and bird life are also not predicted to occur and thus flow on effects would not be expected.
With regard to the effects of the proposed earthworks and vegetation clearance at the WWTP site, including in the SEA overlay, to provide for the WWTP upgrade, the following conclusions are relevant:
• The proposed WWTP expansion has been configured to retain as much SEA vegetation as possible and avoid the need to infill the remaining stream and wetland habitats at the site;
• The suite of proposed mitigation measures will ensure that any adverse effects are minimised; and
• The additional buffering effect and habitat provided by the proposed planting areas will result in a net ecological gain at the WWTP site.
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6. MONITORING AND MANAGEMENT FRAMEWORK
6.1 INTRODUCTION
The following section outlines the overall approach that Watercare proposes for environmental management and monitoring programmes for the short and long term operation of the WWTPs. The approaches identified below will be the basis on which Watercare will propose conditions for the various resource consents that are being sought.
In particular, an Environmental Management Plan will be developed as part of this consent application that will address both the short and long term situations. The following is the type of monitoring that Watercare anticipates being included in the Environmental Management Plan, and where appropriate, provided for in resource consent conditions.
6.2 MANAGEMENT PLANS
Wildlands’ ecological assessment included a series of management plans, which are to be implemented to avoid or mitigate the potential effects of the upgrades of the WWTP. These management plans include:
• A Lizard Management Plan;
• An Avifauna Management Plan;
• An Erosion and Sediment Control Plan; and
• An Ecological Management Plan.
C2HM Beca’s Technical Odour Assessment proposes that the WWTP be operated in accordance with an Operations Management Plan or Air Quality Management Plan (“OMP” or “AQMP”).
Watercare propose that each of these plans is provided for through any consent conditions for the activities, and their proposed contents are outlined in the subsections below.
Ecological Management Plan
Wildlands consider that the planting to undertaken at the WWTP site be guided by an Ecological Management Plan that includes as a minimum:
• Recommended site preparation methodologies;
• Recommended plant schedules for all planting areas that specify the species, number and grade of plants to be planted;
• Recommended plant maintenance actions to be carried out to ensure that the plants establish successfully;
• Timeline for works; and
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• Reporting requirements to Auckland Council.
Further, Wildlands recommends that the plants should mainly comprise early successional species, with a small proportion of secondary species. Overall, plants should be planted at spacings of approximately 1.4 metres and following site preparation and planting, the planted trees and shrubs would need to be maintained for five years to ensure they establish successfully and replanted where they do not become established.
All plants should, to the greatest extent practicable, be eco-sourced from the Rodney Ecological District and sourced from a nursery that implements the New Zealand Plant Producers Incorporated Myrtle Rust Nursery Management Protocol. A signed Myrtle Rust Nursery Management Declaration should be requested from the nursery at the time of planting.
Avifauna Management Plan
To avoid the potential effect of the works required to upgrade the WWTP on avifauna, it is proposed that an Avifauna Management Plan be prepared in consultation with the Shakespeare Open Sanctuary. The Avifauna Management Plan shall address, as a minimum, the following:
• Recommended methodology and timing for vegetation removal to minimise risk to kiwi and other birds;
• Recommendations for the installation of fences to prevent kiwi access to the works sites and other parts of the site (if necessary);
• Timeline for works;
• Protocols for actions if kiwi are found within the works footprint; and
• Reporting requirements to both Auckland Council and the Department of Conservation.
Lizard Management Plan
To avoid the potential effects of the works required to upgrade the WWTP on lizards, it is proposed that a Lizard Management Plan be prepared and implemented to guide a program of capture and relocation. The Lizard Management Plan shall, as a minimum, contain:
• Details of the survey techniques used to assess habitat values and mitigation requirements;
• Recommended methodology for lizard search and rescue prior to clearance;
• Recommended methodology for lizard salvage during clearance;
• Timeline for works including timing of applications for appropriate permissions from the Department of Conservation;
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• Details of release location for any relocated lizards;
• Recommendations for the installation of fences to prevent lizard access to the works sites during the construction phase of the project (if necessary); and
• Reporting requirements to both Auckland Council and the Department of Conservation.
Lastly, it is noted that in order for the lizard salvage works to be carried out, the vegetation removal will occur within the approved lizard salvage season (September to April inclusive).
Erosion and Sediment Control Plan
Any Erosion and Sediment Control Plan for the WWTP upgrade works shall be prepared and implemented in accordance with GD2016/005 - Erosion and Sediment Control Guide for Land Disturbing activities in the Auckland Region’.
Operations Management Plan / Air Quality Management Plan
Watercare currently implements a Management Plan for odour at most of its WWTP sites. The primary objective of the plans is to control and reduce the potential for odour generation to occur, which could give rise to off-site effects.
For the Army Bay WWTP, Watercare propose to prepare the OMP / AQMP prior to the first upgrade of the WWTP becoming operational. The OMP / AQMP will describe the following methods to minimise the generation of odours:
• Housekeeping procedures at the WWTP;
• Inspections and maintenance of all odour containment and ventilation systems (e.g. biofilters, fans, ducting, tanks);
• Contingency methods for plant malfunctions;
• Odour monitoring methodology;
• Complaints investigation, follow up and resolution procedures;
• Testing and maintenance programmes for standby generators;
• Training procedures for operators regarding the methods to be used to control odours; and
• A requirement for an annual review.
The OMP / AQMP will be revised within six months of the each upgrade to the WWTP.
Further, six months prior to the operation of Stage 1 WWTP upgrade, the OMP / AQMP will be prepared and provided to the Council for approval.
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6.3 WASTEWATER MONITORING
Prior to the discharge of treated wastewater, Watercare undertakes flow and quality monitoring to ensure that all quantity, rate and quality limits are being met.
6.4 BENTHIC HABITATS IN THE CMA
With regard to the benthic environment, at present there are no monitoring requirements of the benthic habitat near the outfall. Because of the increased loads (but decreased concentrations) that will arise as populations expand some ecological and sediment quality periodic monitoring will be undertaken near the outfall. Monitoring will include:
• Sediment grain size (which goes with ecology);
• Sediment, organic carbon content, and TN and TP concentrations;
• Benthic infauna and epifauna;
• Heavy metals; and
• Macroalgal cover and extent.
The monitoring will include a site near the outfall and two further afield. This monitoring will be undertaken at two year intervals for the first 10 years and then reviewed.
The surveys will be undertaken over a gradient away from the outfall every 2 years for the first 10 years following the Stage 1 WWTP upgrades and discharge becoming operational.
6.5 WATER QUALITY IN THE CMA
Further to the wastewater discharge monitoring at the WWTP prior to discharge, Watercare also propose to undertake water quality monitoring at one site within the coastal receiving environment. This site will be within the Whangaparaoa Passage and will subject to monthly monitoring for nutrients and chl-a.
6.6 SHELLFISH
Shellfish will be monitored at least annually at the inshore site adjacent to the outfall for E.coli and viruses.
6.7 EMERGING CONTAMINANTS
While the environmental risk from emerging contaminants is currently considered low (Section 5.5.2.2), the risk could change over time as new chemicals come into usage. It is proposed that this risk be reassessed every five years through an Emerging Contaminants Risk Assessment that would:
• Review changes in the state of knowledge of emerging contaminants;
• Undertake measurements if required; and
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• Consider the risks to the environment from emerging contaminants in the treated wastewater discharged from the WWTP.
6.8 ENIVRONMENTAL MANAGEMENT PLAN
To integrate operational practices at the WWTP, the environmental monitoring, and the reporting of results, an Environmental Management Plan will be prepared. It is proposed that this contain information on:
• The area served by the treatment plant;
• Inspection and maintenance undertaken;
• Monitoring and reporting of:
• Wastewater flow
• Treated wastewater quality
• Surface water monitoring
• Ecological monitoring
• Sampling processes and methodologies
• Complaints procedures; and
• Contingency and Incident Management.
The intention would be for the Environmental Management Plan to be a ‘live’ document that could be updated, subject to approval by Auckland Council. The Environmental Management Plan would be submitted to Auckland Council within six months of the resource consents commencing.
6.9 REVIEW OF ENVIRONMENTAL MONITORING DATA
Following the implementation of the Stage 1 WWTP upgrade, it is proposed that the environmental monitoring data be reviewed every five years to assess any trends over time and whether there is any evidence that nutrients sourced from the WWTP are causing a deterioration of coastal water quality. The results of these reviews and any proposed amendments to the monitoring programmes or the Environmental Management Plan shall be provided to the Auckland Council for approval.
6.10 ANNUAL REPORTING
Watercare proposes to prepare a report each year to Auckland Council providing information on all monitoring data collected for that year, including analysis of it, comment on plant performance and trends in changes in discharge volume or quality, discussions on compliance, and in the event of any non-compliance, discussion of the reasons for this and a timetable to rectify any non-compliance.
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6.11 ON-GOING CONSULTATION
Watercare is committed to ongoing consultation with all stakeholders and anticipates sharing the information described in this section with them.
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7. CONSULTATION
7.1 INTRODUCTION
Watercare has undertaken a targeted consultation process in relation to the Project and Watercare has engaged with iwi, community groups, key stakeholders and the wider public. In addition to the consultation already undertaken, Watercare is committed to maintaining an on-going relationship with iwi and key stakeholders through the application process and beyond.
A Consultation Summary Table has been included as Volume 2, Appendix L and the consultation process is summarised below.
7.2 IWI CONSULTATION
An established process is in place for iwi engagement on all Projects initiated by Watercare. This process includes early notification of works to be undertaken which do or are likely to require a resource consent, and the provision for clear and open communication.
Six iwi entities have been identified through the pre-application process as potentially having an interest in the Project. These parties were:
• Ngāti Whanaunga;
• Ngāti Maru;
• Te Kawerau a Maki;
• Te Rūnanga o Ngāti Whātua;
• Ngāi Tai Ki Tāmaki; and
• Ngāti Manuhiri.
The engagement process commenced with a Project information package being sent out in September 2017.
Of the parties notified, the following provided a request to be involved in the pre-application phase of the Project:
• Ngāti Whanaunga;
• Ngāti Maru;
• Te Kawerau a Maki;
• Ngāi Tai Ki Tāmaki; and
• Ngāti Manuhiri.
Further, Te Rūnanga o Ngāti Whātua deferred their position on the Project to Ngāti Manuhiri.
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As outlined in Section 4.3, Ngāti Manuhiri and Ngāti Whanaunga prepared CVAs for the Project which have been used to inform this AEE. The CVAs have been provided are confidential documents for Watercare’s use only and the specific iwi should be contacted directly if other parties would like to view them.
As summarised in Section 2 and explained in detail in the Preferred Options Report (Volume 2, Appendix B), the five iwi parties participated extensively in the Preferred Option selection process with the input received playing a fundamental part in the Process.
Following the selection of the Preferred Option, Ngāti Manuhiri, Ngāti Whanaunga and Te Kawerau a Maki confirmed that they did not wish to provide a CIA for the discharge aspect of the Project. The other parties were silent on the need for a CIA but Watercare leave the opportunity open to these parties.
Watercare has conveyed to iwi the importance of a meaningful and ongoing relation with mana whenua following lodgement of the application and Watercare is committed to ensuring that these relationships are provided for and maintained.
Marine and Coastal Area (Takutai Moana) Act 2011
In addition to the mana whenua engagement outlined above, section 62(3) of the Marine and Coastal Area (Takutai Moana) Act 2011 (“MACA Act”) requires that before an application is lodged under the RMA that relates to a right conferred by a customary marine title order or agreement, the applicant must notify the applicant group about the application and seek the views of the group on the application.
Watercare notified and sought the views of the following parties on 2 November 2018:
• Mahinepua Reserve Ririwha Trust;
• Ngāi Tai ki Tāmaki Trust;
• Ngapuhi Nui Tonu;
• Ngapuhi Nui Tonu-Kota-toka-tutaha-moana o whaingaroa;
• Ngāti Kawau te Kōtuku, Te Uri o Te Aho, Ngāti Kuri, and Te Waiariki Korora nga Hapū o Ngāpuhi-Nui-Tonu;
• Ngāti Manuhiri;
• Ngati Rongo o Mahurangi;
• Ngati Te Ata;
• Ngāti Whanaunga;
• Te Hikutu whanau and hapu;
• Te Kaunihera Maori o Te Tai Tokerau;
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• Te Kawerau a Maki; and
• Te Uri Taniwha.
Following the notification, Watercare have received the following feedback to date:
• Ngati Rongo o Mahurangi – 2 November 2018 via email – Advised that the group objects to any discharges into their ancestral water and identified themselves as mana whenua.
Watercare acknowledge the position from Ngati Rongo o Mahurangi;
• Ngapuhi Nui Tonu – 2 November 2018 via email – Requested a site visit, introductory consultation, time to review reports and prepare a CIA, Project sign off and possible provision for cultural monitors.
Watercare is currently in the process of arranging a site visit and introductions for Ngapuhi Nui Tonu and will provide updates to Council on any further progress;
• Ngāti Kawau te Kōtuku, Te Uri o Te Aho, Ngāti Kuri, Te Waiariki Korora nga Hapū o Ngāpuhi-Nui-Tonu – 8 November via email – Parties cannot currently review the application as it is awaiting funding from the Crown and until such a time it objects to the application and progressing with the application runs contrary to their MACA Act application.
Watercare acknowledge the position of the parties and note that it will be requesting the application be publicly notified which will enable parties who wish to lodge a submission to become formally involved in the application process.
7.3 STAKEHOLDER AND PUBLIC CONSULTATION
Local Board and Councillors
As part of the preapplication process, Watercare directly engaged with the members of both the Hibiscus and Bays Local Board and also the Auckland Council Councillors for the area. This engagement was through a mix of email correspondence and provision of Project information presentation, presentations, site visits and face to face meetings which occurred between September 2017 – June 2018 to reflect the progression of the preapplication process.
Overall, feedback from the Board and Councillors was generally supportive of Watercare’s approach to the Project in particular the Preferred Option Selection process and the early and ongoing involvement of mana whenua in the Project. Concern was expressed over the amount of population growth and ability for the wastewater network to handle this growth and Watercare outlined that there was also complimentary work streams going on to upgrade the conveyance network and also looking into the stormwater inflows and
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infiltration into the network and that through these work streams Watercare expects to see significant improvements in the network operations.
Public Consultation
As outlined in Section 2 and detailed in the Preferred Option Report (Volume 2, Appendix B), Watercare held three Open Days on:
• 14 and 15 February 2018 – presenting the Long-List Options for wastewater treatment and discharge; and
• 20 June 2018 – presenting the final two wastewater treatment and discharge options and providing an overview of the process to reach the final two options.
The purpose of these open days was to inform the community on the alternative options that Watercare were investigating and to provide the communities with the opportunity to provide feedback and ask questions. Watercare staff and their technical experts were available to discuss the Project with members of the public.
Attendance at these open days was limited only six (6) individuals / groups attending in total. Feedback received was both positive and negative with a range of comments on the water quality at beaches on the Whangaparaoa Peninsula, funding of any improvements and network overflows issues, as well as supporting the thorough process that Watercare had undertaken in the options consideration process.
In addition to these Open Days, Watercare also had direct engagement in the form of emails and meetings with the following local residents:
• 20 March 2018 - Tom Parsons and Windsbury White –The meeting included introductions to Project team, a summary of the BPO process, and what had been done to date, where we are now, and what’s next. General feedback received was that they were happy with the work which was done and had no concerns that needed to be addressing; and
• 4 July 2018 – Brian Sharplin – The meeting included a summary of the Project and a detailed overview of the Preferred Option Selection Process and general discussion about Brian’s informal submission in opposition to the expansion of the Army Bay WWTP and the conveyance network. Watercare agreed to notify Brian directly once the application was lodged.
Additionally, Watercare also had a Project specific website through which it provides updates and notice of Open Days, shared information about the Project and provided an email address for parties that had any questions. The website can be found at the following link: https://www.watercare.co.nz/About-us/Projects-around-Auckland/Wastewater- servicing-project-for-Whangaparaoa-and
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Stakeholder Consultation
Watercare also undertook targeted stakeholder consultation as part of the preapplication process. This involved:
• 4 and 12 December 2017 - Emailing a Project overview flyer to 41 local stakeholders consisting of community groups, business associations, golf clubs and the Shakespear Regional Park and Open Sanctuary;
• 6 December 2017 – Attendance at the monthly Shakespear Regional Park and Open Sanctuary meeting to discuss future potential to use TSE for land application on Shakespeare Park and briefed the group on the Watercare consultation process regarding the consent application for treated WW discharge as well as outlined the several options for discharges of the treated effluent to land including within the Park;
• 2 February 2018 – Further Project update flyer provided to the 41 local stakeholder and informing parties of the February Open Days to be held;
• 27 February 2018 – Gulf Harbour Country Club – Meeting to explore the future potential for land application of treated wastewater for irrigation of the golf course and greens however, it was communicated that they had sufficient water to meet their irrigation requirements;
• 8 March 2018 – Wainui Golf Club - Meeting to explore the future potential for land application of treated wastewater for irrigation of the golf course and greens however, it was communicated that they had sufficient water to meet their irrigation requirements but there may be potential opportunities in the future; and
• 29 May 2018 - Further Project update flyer provided to the 41 local stakeholder and informing parties of the 20 June Open Day to be held.
The Consultation Summary Table (Volume 2, Appendix L) also provides a detailed list of when the Project newsletters and flyers that were circulated to the public and stakeholders.
Further to the above, Watercare has also maintained on-going consultation with the Auckland Council throughout the pre-application process and pre-application discussions have been held with Auckland Council Parks Major Infrastructure Projects Team, and the Planning Team.
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8. STATUTORY CONSIDERATIONS
8.1 INTRODUCTION
The RMA is the principal statutory document governing the use of land, air and water. The purpose of the RMA, as set out in section 5, is to “promote the sustainable management of natural and physical resources”. This section of the AEE sets out the framework under the RMA that applies to the resource consents that are being sought from Auckland Council for the Project.
8.2 AUCKLAND UNITARY PLAN – OPERATIVE IN PART
The Unitary Plan is the sole statutory planning document that contains rules relevant to operational aspects of the Army Bay WWTP. In this regard, there are no remaining appeals on the Unitary Plan that affect the status of the rules that apply to this Project.
Zoning and Overlays
The site is zoned Open Space - Informal Recreation Zone, and subject to Designation 9362 for wastewater purposes being sewerage treatment and disposal in Watercare’s name. The site is located in the high air quality area. The majority of the site is subject to SEA_T_6999m, with the exception of the existing footprint of the WWTP. SEA_T_4208, and Outstanding Natural Landscapes Overlay – Area 50 (“ONL – Area 50”) also overlay the site along its south-west and north-west margins respectively however, no works applied for here are within SEA_T_4208 and ONL – Area 50.
The Unitary Plan sets out that the Open Space – Conservation Zone applies to open spaces with natural, ecological, landscape, and cultural and historic heritage values.
SEA_T_6999m meets the following SEA factors:
2 Threat status and rarity;
3 Diversity; and
4 Stepping-stones, migration pathways and buffers.
SEA_T_4208 meets factors two and four.
ONL Area 50 comprises high values when assessed against the WESI criteria utilised by Auckland Council in terms of geographical and topographical, ecological, dynamic, memorability, expressiveness, and transient value factors, and high/moderate values in terms of naturalness.
The wastewater discharge point is located in the General Coastal Marine Zone, and is not subject to any overlays.
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Permitted Activities Relied Upon
The conservation planting undertaken in accordance with the Ecological Management Plan to be prepared for the WWTP site is provided for as a permitted activity in accordance with Table E15.4.2, Rule A37. This planting is for ecological restoration purposes in line with Standard E15.6.3 of the Unitary Plan.
Resource Consent Requirements and Activity Status
Watercare are seeking the all necessary resource consents for the operation of the Army Bay WWTP, and discharge of wastewater from the Army Bay WWTP.
An analysis of the relevant rules from the Unitary Plan is provided in the sections below.
8.2.3.1 Discharge to Air
The discharge of contaminants to air from wastewater treatment processes is provided for as a discretionary activity in accordance with Table E14.4.1, Rule A163.
8.2.3.2 Discharge of Wastewater
The discharge of treated wastewater from a wastewater treatment plant to the General Coastal Marine Zone is provided for as a discretionary activity in accordance with Table F2.19.7, Rule A69.
8.2.3.3 Vegetation Removal
With regard to the vegetation removal and earthworks associated with the WWTP upgrades, Chapter E26 of the Unitary Plan provides for these activities on the basis of the Auckland- wide provisions. Therefore, where appropriate, resource consent is required under the rules in Chapter E26.
Of the 4,000 m2 of vegetation removal required to upgrade the WWTP, up to 2,185 m2 of is within SEA_T_6999m, this comprises the areas shown in Figure 22. The clearance of vegetation in SEA_T_6999m is provided for as a restricted discretionary activity in accordance with Table E26.3.3.1, Rule A77.
The remaining vegetation removal, approximately 1,815 m2, which is located outside of a SEA and in the Open Space zone is provided for as a restricted discretionary activity in accordance with Table E15.4.1, Rule A10 as Table E26.3.3.1 .does not provide for vegetation removal in the Open Space zone that is associated with infrastructure.
8.2.3.4 Earthworks
Further to the vegetation removal set out above, to upgrade the WWTP the same areas will require earthworks. Earthworks are provided for as a restricted discretionary activity in accordance with Table E26.5.3.1, Rule A97 and Rule A97A. However, as approximately
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2,185 m2 of earthworks will occur within SEA_T_6999m they also require resource consent for a discretionary activity in accordance with Table E26.6.3.1, Rule A118.
8.2.3.5 Summary
The overall activity status for the Project is a discretionary activity under the Unitary Plan.
8.3 SECTION 104 ASSESSMENT
Overview
Section 104 of the RMA lists the matters that a consent authority must have regard to in determining whether a resource consent application should be granted. It states:
1) When considering an application for a resource consent and any submissions received, the consent authority must, subject to Part 2, have regard to– a) any actual and potential effects on the environment of allowing the activity; ab) any measure proposed or agreed to by the applicant for the purpose of ensuring positive effects on the environment to offset or compensate for any adverse effects on the environment that will or may result from allowing the activity; and b) any relevant provisions of— i) a national environmental standard: ii) other regulations: iii) a national policy statement: iv) a New Zealand coastal policy statement: v) a regional policy statement or proposed regional policy statement: vi) a plan or proposed plan; and c) any other matter the consent authority considers relevant and reasonably necessary to determine the application. 2) When forming an opinion for the purposes of subsection (1)(a), a consent authority may disregard an adverse effect of the activity on the environment if a national environmental standard or the plan permits an activity with that effect. 2A) When considering an application affected by section 124 or 165ZH(1)(c), the consent authority must have regard to the value of the investment of the existing consent holder.
Section 104 of the RMA does not give any of the matters to which a consent authority is required to have regard primacy over any other matter.
All of the relevant matters are to be given such weight as the consent authority sees fit in the circumstances, and all provisions are subject to Part 2 of the RMA.
Actual and Potential Effects
With respect to section 104(1)(a) of the RMA, the actual and potential effects on the environment in respect to the discharge of wastewater to the CMA, discharge of contaminants to air from the treatment of wastewater at the Army Bay WWTP, and vegetation clearance and land disturbance within a SEA are set out in Section 5 of this AEE. By way of summary, it is concluded that all adverse effects can be appropriately avoided, remedied or
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mitigated such that the activities will achieve the sustainable management purpose of the RMA.
Relevant Statutory Planning Documents
In terms of section 104(1)(b) of the RMA, the following sub-sections provide an assessment of the activities associated with the construction, operation, and maintenance of the retirement village against the:
• New Zealand Coastal Policy Statement 2010 (“NZCPS”)
• National Policy Statement on Urban Development Capacity 2016 (“NPS UDC”); and
• Auckland Unitary Plan – Operative in Part.
New Zealand Coastal Policy Statement 2010
The NZCPS contains seven objectives and 29 policies that seek to achieve the purpose of the RMA in relation to the coastal environment. The following objectives and policies are relevant to the Project:
Objective 1
To safeguard the integrity, form, functioning and resilience of the coastal environment and sustain its ecosystems, including marine and intertidal areas, estuaries, dunes and land, by:
• maintaining or enhancing natural biological and physical processes in the coastal environment and recognising their dynamic, complex and interdependent nature;
• protecting representative or significant natural ecosystems and sites of biological importance and maintaining the diversity of New Zealand’s indigenous coastal flora and fauna; and
• maintaining coastal water quality, and enhancing it where it has deteriorated from what would otherwise be its natural condition, with significant adverse effects on ecology and habitat, because of discharges associated with human activity.
Objective 2
To preserve the natural character of the coastal environment and protect natural features and landscape values through:
• recognising the characteristics and qualities that contribute to natural character, natural features and landscape values and their location and distribution;
• identifying those areas where various forms of subdivision, use, and development would be inappropriate and protecting them from such activities; and
• encouraging restoration of the coastal environment.
The ongoing discharge of wastewater will be to the coastal environment. The operation of the Army Bay WWTP and subsequent discharge of wastewater will be undertaken in a manner which will safeguard the integrity, form, functioning and resilience of the coastal
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environment and sustain its ecosystems, including marine and intertidal areas, estuaries, dunes and land, and which protects the natural features of the coastal environment. This will be achieved through the implementation of high quality wastewater treatment at the WWTP prior to any discharges into the coastal environment. Discharges from the Army Bay WWTP will have minimal and localised effects on coastal water quality due to the improved discharge quality, as described in Section 5.
Objective 3
To take account of the principles of the Treaty of Waitangi, recognise the role of tangata whenua as kaitiaki and provide for tangata whenua involvement in management of the coastal environment by:
• recognising the ongoing and enduring relationship of tangata whenua over their lands, rohe and resources;
• promoting meaningful relationships and interactions between tangata whenua and persons exercising functions and powers under the Act;
• incorporating mātauranga Māori into sustainable management practices; and
• recognising and protecting characteristics of the coastal environment that are of special value to tangata whenua.
As outlined in Section 7, Watercare recognises the role of mana whenua as kaitiaki, has involved iwi in this consent process through a robust consultation process. To further provide for this, Watercare has also made commitments to mana whenua parties to continue to engage with parties following the lodgement of the application and in the event that the applications are granted.
Objective 4
To maintain and enhance the public open space qualities and recreation opportunities of the coastal environment by:
• recognising that the coastal marine area is an extensive area of public space for the public to use and enjoy;
• …
Objective 6
To enable people and communities to provide for their social, economic, and cultural wellbeing and their health and safety, through subdivision, use, and development, recognising that:
• the protection of the values of the coastal environment does not preclude use and development in appropriate places and forms, and within appropriate limits;
• some uses and developments which depend upon the use of natural and physical resources in the coastal environment are important to the social, economic and cultural wellbeing of people and communities;
• functionally some uses and developments can only be located on the coast or in the coastal marine area;
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• the coastal environment contains renewable energy resources of significant value;
• the protection of habitats of living marine resources contributes to the social, economic and cultural wellbeing of people and communities;
• the potential to protect, use, and develop natural and physical resources in the coastal marine area should not be compromised by activities on land;
• the proportion of the coastal marine area under any formal protection is small and therefore management under the Act is an important means by which the natural resources of the coastal marine area can be protected; and
• historic heritage in the coastal environment is extensive but not fully known, and vulnerable to loss or damage from inappropriate subdivision, use, and development.
The continued operation of the Army Bay WWTP will enable people and communities to provide for their social, economic and cultural wellbeing, health and safety through the provision of immediate and long-term wastewater management for the service areas.
This objective clearly anticipates that some use and development of the coastal environment will occur, provided (for example) it occurs in appropriate places and forms, and operates within appropriate limits. As described in Section 2, Watercare undertook a thorough alternative options evaluation process which demonstrates the treatment of wastewater at the Army Bay WWTP and discharge to the Whangaparaoa Passage represents the BPO as defined in the RMA therefore, it was determine that the discharge activity has a functional need to be located within the coastal environment.
Policy 2 The Treaty of Waitangi, tangata whenua and Māori heritage In taking account of the principles of the Treaty of Waitangi (Te Tiriti o Waitangi), and kaitiakitanga, in relation to the coastal environment: (a) recognise that tangata whenua have traditional and continuing cultural relationships with areas of the coastal environment, including places where they have lived and fished for generations; … (d) provide opportunities in appropriate circumstances for Māori involvement in decision making, for example when a consent application or notice of requirement is dealing with cultural localities or issues of cultural significance, and Māori experts, including pūkenga2, may have knowledge not otherwise available; … Policy 2 outlines a range of methodologies for taking into account the principles of the Treaty of Waitangi and kaitiakitanga in relation to the coastal environment. As outlined in Section 7, Watercare has, and will continue to, actively engage with mana whenua in respect of these resource consent applications. Through this process, input from mana whenua into the Project considered and provided for where possible, including an assessment of additional option in the Process, and fatal flawing of potential options based on mana whenua input.
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Policy 6 Activities in the coastal environment (1) In relation to the coastal environment: (a) recognise that the provision of infrastructure, the supply and transport of energy including the generation and transmission of electricity, and the extraction of minerals are activities important to the social, economic and cultural well-being of people and communities; (b) consider the rate at which built development and the associated public infrastructure should be enabled to provide for the reasonably foreseeable needs of population growth without compromising the other values of the coastal environment; (c) encourage the consolidation of existing coastal settlements and urban areas where this will contribute to the avoidance or mitigation of sprawling or sporadic patterns of settlement and urban growth; … (h) consider how adverse visual impacts of development can be avoided in areas sensitive to such effects, such as headlands and prominent ridgelines, and as far as practicable and reasonable apply controls or conditions to avoid those effects; … (2) Additionally, in relation to the coastal marine area: (a) recognise potential contributions to the social, economic and cultural wellbeing of people and communities from use and development of the coastal marine area, including the potential for renewable marine energy to contribute to meeting the energy needs of future generations: (b) recognise the need to maintain and enhance the public open space and recreation qualities and values of the coastal marine area; (c) recognise that there are activities that have a functional need to be located in the coastal marine area, and provide for those activities in appropriate places; (d) recognise that activities that do not have a functional need for location in the coastal marine area generally should not be located there; and (e) promote the efficient use of occupied space, including by: … (ii) requiring the removal of any abandoned or redundant structure that has no heritage, amenity or reuse value; and … Policy 6 recognises that the provision of infrastructure is important to the social, economic and cultural wellbeing of people and communities. The Project has been developed based on long-term population growth rates in the Whangaparaoa, Orewa, Red Beach, Hatfields, Silverdale, Wainui, Dairy Flat, Stillwater, Okura Bush and Redvale communities. The assessment of effects provided in Section 5 conclude that the effects of the Project have been minimised and will not compromise the values of the coastal environment.
Policy 23 Discharge of contaminants (1) In managing discharges to water in the coastal environment, have particular regard to: (a) the sensitivity of the receiving environment; (b) the nature of the contaminants to be discharged, the particular concentration of contaminants needed to achieve the required water
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quality in the receiving environment, and the risks if that concentration of contaminants is exceeded; and (c) the capacity of the receiving environment to assimilate the contaminants; and: (d) avoid significant adverse effects on ecosystems and habitats after reasonable mixing; (e) use the smallest mixing zone necessary to achieve the required water quality in the receiving environment; and (f) minimise adverse effects on the life-supporting capacity of water within a mixing zone. (2) In managing discharge of human sewage, do not allow: (a) discharge of human sewage directly to water in the coastal environment without treatment; and (b) the discharge of treated human sewage to water in the coastal environment, unless: (i) there has been adequate consideration of alternative methods, sites and routes for undertaking the discharge; and (ii) informed by an understanding of tangata whenua values and the effects on them. …
The discharge from the Army Bay WWTP takes place within the coastal environment. Section 4 describes the sensitivity of the receiving environment (Policy 23(1)(a)).
The contaminants in the discharges and their effects are described in Section 3 and Section 5. As discussed in Section 5, due to the rapid dilution and dispersion that will occur in the Whangaparaoa Passage combined with an improved level of treatment, there will not be any detectable or ecologically significant change in the receiving environment
The wastewater to be discharge to the CMA, in the long-term, will be of an improved quality in comparison to that currently being discharged. Modelling demonstrates that the long- term discharge will not have an adverse effect on the water quality of the receiving environment, and be indistinguishable from background levels. The Project is therefore considered to be consistent with Policies 23(1)(b) and (c).
Any adverse effects of the discharge are confined to within very close proximity of the discharge point, beyond which mixing will occur. The effects assessment undertaken in support of this application concludes that there will be no adverse effects on ecosystems and habitats from the discharge, and the effects on the life-supporting capacity of water within the mixing zone will be minimal. Therefore, it is considered that the outcomes sought by Policies 23 (1)(d)-(f) will be achieved by the Project.
This application does not include discharges of human sewage directly to water in the coastal environment without treatment, and therefore satisfies Policy 23(2)(a).
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The discharges of treated wastewater proposed in this application were arrived at following an extensive assessment of alternatives as described in Section 2 and the consultation as described in Section 7. This process is consistent with the direction of Policy 23(2)(b)(i).
NZCPS Summary
The Project will be consistent with the overarching direction of the objectives and policies in the NZCPS.
In particular, the discharge of treated wastewater from the existing outfall, will not result in significant adverse effects on the CMA. Furthermore, the decision to continue to discharge treated wastewater to the CMA was the outcome of a robust and transparent alternative options analysis, informed by mana whenua values.
Overall, the Project is considered to be consistent with the provisions of the NZCPS.
National Policy Statement on Urban Development Capacity 2016
The NPS UDC provides direction on planning for urban environments and recognises the significance of well-functioning urban environments. With regard to the Project, the NPS UDC notes that development capacity must be supported by infrastructure and that urban development is dependent on the development of infrastructure. Policies PA1 to PA4 apply to any urban environment that is expected to experience growth, and of these policies, the Project assists Auckland Council in achieving the outcomes sought by policies PA2 and PA3.
…
PA2: Local authorities shall satisfy themselves that other infrastructure required to support urban development are likely to be available.
PA3: When making planning decisions that affect the way and the rate at which development capacity is provided, decision-makers shall provide for the social, economic, cultural and environmental wellbeing of people and communities and future generations, whilst having particular regard to:
a) Providing for choices that will meet the needs of people and communities and future generations for a range of dwelling types and locations, working environments and places to locate businesses;
b) Promoting the efficient use of urban land and development infrastructure and other infrastructure; and
c) Limiting as much as possible adverse impacts on the competitive operation of land and development markets.
…
PA2 seeks that infrastructure is available to support development, in this regard the Project will ensure wastewater treatment and disposal for the service areas is available through to 2053 with the potential to expand the Project beyond 2053 and/or as required.
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PA3 provides direction regarding planning decisions that affect the way and rate at which development capacity is provided. In this regard, the treatment and disposal of wastewater has a direct impact on the ability for development to occur within the service areas. The Project will provide for the social, economic, cultural and environmental wellbeing of people and communities and future generations through the treatment and discharge of wastewater throughout the consent timeframe, whilst also maintaining potential to do so beyond the consented timeframe or population estimates if required.
In light of the above, the Project is considered to assist Auckland Council with achieving the outcomes sought be the NPS UDC.
Auckland Unitary Plan – Operative in part
As noted in Section 8.2 of this AEE, the Army Bay WWTP site is zoned Open Space – Informal Recreation, subject to Designation 9362 for wastewater, and located in the high air quality area. The wastewater discharge point is located in the General Coastal Marine Zone, and is not subject to any overlays.
The relevant objectives and policies of the Unitary Plan are assessed in detail in Volume 2, Appendix M to this AEE, and a summary is provided below.
8.3.6.1 Mana Whenua
Chapter B6 of the Unitary Plan contains provisions relating to Mana Whenua that seek the recognition of the provisions of the Treaty of Waitangi, Mana Whenua participation in the resource management process, sufficient weighting of Mana Whenua values in decisions, overall enhancement of the mauri and Mana Whenua relationships with natural and physical resources, and that Mana Whenua cultural heritage is protected.
Conclusions in relation to the Mana Whenua objectives and policies are:
• Mana Whenua has been extensively involved in the pre-application phase of the Project and participated throughout the Preferred Option selection process and their values and relationships with the natural and physical resources, communicated by way of Cultural Values Assessments, have been considered, and where necessary provided for, throughout this Project.
• While Mana Whenua have expressed that it is their preference that treated wastewater be discharged to land, those who have participated in the Project to date have indicated that they accept the preferred option as a coastal discharge as they have been part of the selection process.
• Watercare will maintain an on-going relationship with mana whenua following lodgement of the applications and granting of any resource consents and this will further enable Mana Whenua to exercise their kaitiakitanga over the Project area.
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8.3.6.2 Discharge of Wastewater
The key outcomes sought by the provisions with regard to the discharge of treated wastewater to the General Coastal Marine Zone are:
• Development, operation, maintenance, and upgrading of infrastructure is enabled, while managing adverse effects, and the benefits of infrastructure are recognised;
• Avoid or minimise significant bacteria contamination, adverse effects on coastal water quality, and adverse effects on Mana Whenua values;
• Adoption of the best practicable option for discharges from wastewater treatment plants;
• Adopt a precautionary approach towards proposed activities whose effects on the coastal environment are uncertain, unknown or little understood, but could be significantly adverse;
• Maintain water and sediment quality;
• Wastewater networks protect public health and safety by preventing or minimising the adverse effects of contaminants on the coastal water quality; and
• For the discharge of wastewater to the coastal marine area, require:
• Consideration of alternative methods, sites and routes for the discharge;
• Consultation with Mana Whenua;
• Consultation with the affected community; and
• Consideration of the extent to which adverse effects on recreational and shell fishing gathering, maintenance dredging, high ecological value, and marine farm areas are avoided, remedied or mitigated.
Conclusions in relation to the objectives and policies relevant to the discharge of treated wastewater to the General Coastal Marine Zone are:
• That water quality in the Whangaparaoa Passage is considered to be “excellent” and there is no indication that the existing discharge impacts on water and microbial quality;
• Modelling has shown that there will be a negligible and undetectable change in salinity, water quality will continue to be “excellent”, and the risk of algal blooms will not increase;
• Watercare has undertaken a detailed alternative options consideration process which has involved technical experts, stakeholders, mana whenua and the public.
• Watercare is undertaking further ‘inflow and infiltration’ investigations into the into the current network within the Whangaparaoa Peninsula. The findings of this work will
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enable Watercare to identify where flows are entering the network which will allow inflows to the WWTP to be managed more efficiently.
• The Ecological Assessment (Volume 2, Appendix E) notes that the Whangaparaoa Passage is a dynamic and well flushed coastal environment with high currents and strong flows. It also notes that water quality is considered to be “excellent” and that there is no indication that the existing discharge impacts on water and microbial quality.
• The overall quality of the wastewater discharge will be improved over time as the WWTP is upgraded to an MBR system with appropriate limits consented to reflect this;
• The WWTP will contribute less than 1 % of the total annual load of nitrogen to the Hauraki Gulf, including the loadings from the Snells Beach WWTP and Rosedale WWTP, it is not expected that the water quality status will change or the risk of algal blooms increase; and
• It is not anticipated that the discharge will give rise to adverse effects on Tiritiri Matangi Island.
8.3.6.3 Discharge to Air
The key outcomes sought by the provisions with regard to the discharge to air are:
• That air quality is maintained;
• Significant adverse effects on human health, and offensive and objectionable effects from odour discharges and avoided;
• Reverse sensitivity effects are minimised;
• The best practicable option for emission control is used; and
• The adverse effects on air quality beyond the boundary of the premises where the discharge of contaminants to air is occurring are avoided, remedied or mitigated.
Conclusions in relation to the objectives and policies relevant to the discharge to air are:
• The WWTP will produce low odour emissions;
• Due to the separation distances between the WWTP and high sensitivity receptors, and the channelling effect of hills on wind flows, the risk of people being exposed to adverse odour is low; and
• The WWTP will be managed in accordance with an Operations Management Plan or Air Quality Management Plan.
8.3.6.4 Vegetation Clearance and Land Disturbance
The key outcomes sought by the provisions with regard to vegetation clearance and land disturbance seek to:
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• Protect areas of significant indigenous biodiversity value from the adverse effects of development;
• Enhance indigenous biodiversity values;
• Consider the appropriateness of offsetting adverse effects;
• Recognise that it is not always practicable to locate and design infrastructure to avoid significant ecological areas;
• Sediment generation from land disturbance is minimised; and
• Land disturbance is controlled to achieve soil conservation.
Conclusions in relation to the objectives and policies relevant to the vegetation clearance and land disturbance are:
• Wildland Consultants consider that the effects of the clearance of 1,230 m2 of planted ngaio and manuka (of which ~263 m2 is within the SEA overlay), some of which is in decline, can be mitigated by the planting of approximately 4,242 m2.
• The proposed construction footprint for the WWTP upgrades account for approximately 1.5% of the existing SEA block with the majority of the disturbed area being identified as having low ecological value in the Wildland Assessment;
• The upgrades to the WWTP to increase its treatment capacity will occur generally within the existing footprint of the WWTP site and there will not be any expansion into the coastal environment as part of these works nor will the works expand into the neighbouring Shakespear Regional Park land;
• The proposed planting will therefore result in a net increase in the availability of high value habitats within the WWTP site; and
• Planting will be guided by an Ecological Management Plan.
While the adverse effects of the vegetation removal cannot be avoided, it is considered that the proposed mitigation planting will provide a net positive benefit to the ecological values and functions of the surrounding SEA once it is established.
Mana Whenua have highlighted that they have an interest in being involved in the mitigation planting and remediation works within the SEA, and Watercare is committed to ensuring the appropriate offer are presented to Mana Whenua to be involved.
Watercare propose that an ESCP be prepared as part of the conditions of consent for the WWTP upgrade works. The ESCP will establish appropriate protocols for the management of sediment runoff during construction, in accordance with GD2016/005 - Erosion and Sediment Control Guide for Land Disturbing activities in the Auckland Region.
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Other Relevant Matters
Hauraki Gulf Marine Park Act 2000
The purpose of the Hauraki Gulf Marine Park Act 2000 (“HGMPA”) includes the integration and management of the natural, historic and physical resources of the Hauraki Gulf, its islands, and catchments. The HGMPA is relevant to the Project as involves works within, and discharges to, the Hauraki Gulf and its catchments. Further, section 9(4) of the HGMPA states that a consent authority, when considering an application for a resource consent, must have regard to sections 7 and 8. These sections must be treated as a New Zealand coastal policy statement (section 10(1)).
Section 7 makes the interrelationship between the Hauraki Gulf, its islands and catchments and the ability of that interrelationship to sustain the life supporting capacity of the environment of the Hauraki Gulf a matter of national significance.
Section 8 provides objectives for the management of the Hauraki Gulf, its island and catchments. Namely, its protection, and where appropriate its enhancement. With regards to these objectives, the Project:
• Does not adversely affect the life supporting capacity of Hauraki Gulf, its island and catchments, and through the improvements in the discharge quality the amount of nutrients otherwise entering the Hauraki Gulf will be reduced (section 8(a)). Adverse effects of the treated wastewater discharges will be negligible beyond the mixing zones;
• Has been informed by mana whenua consultation and does not adversely affect the natural, historic or physical resources of the Hauraki Gulf, its islands and catchments (sections 8(b) and (c)); and
• Does not adversely affect the cultural or historic associations of people and communities in and around the Hauraki Gulf and provides social and economic benefits through enabling growth to occur in the communities served by the Army Bay WWTP (sections 8(d), (e), and (f)).
The Project is therefore considered consistent with the provisions of the HGMPA.
8.3.7.1 The Auckland Plan 2050
The Auckland Plan 2050 sets out six outcomes for the Auckland region through to 2050. Relevant to the Project are:
• Māori Identity and Wellbeing; and
• Environment and Cultural Heritage.
The directions and focus areas relevant to each of these outcomes are assessed below.
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Māori Identity and Wellbeing
The relevant directions and focus areas relating to māori identity and wellbeing state:
Direction 1: Advance Māori wellbeing.
Direction 3: Recognise and provide for te Tiriti o Waitangi outcomes.
Focus area 5: Advance mana whenua rangatiratanga in leadership and decision-making and provide for customary rights.
With regard to advancing māori identity and wellbeing, recognising and providing for te Tiriti o Waitangi outcomes, and advancing mana whenua decision making, Watercare consider that the extensive consultation process undertaken with Te Kawerau a Maki, Ngāi Tai Ki Tāmaki, Ngāti Manuhiri and Ngāti Maru, including their involvement in the BPO process has provided consistency with these direction and focus area.
Environment and Cultural Heritage
The relevant directions and focus areas relating to the environment and cultural heritage state:
Direction 1: Ensure Auckland’s natural environment and cultural heritage is valued and cared for.
Direction 2: Apply a Māori world view to treasure and protect our natural environment (taonga tuku iho).
Direction 3: Use Auckland’s growth and development to protect and enhance the natural environment.
Direction 4: Ensure Auckland’s infrastructure is future-proofed.
Focus area 3: Account fully for the past and future impacts of growth.
Watercare’s primary Project Objective is to provide environmentally sustainable wastewater services. This guides Watercare’s approach to discharging treated wastewater to the Coastal Marine Area. Section 5 of this AEE concludes that due to the rapid dilution and dispersion at this site combined with an improved level of treatment, there will not be any detectable or ecologically significant change in the receiving environment even under the conservative assessments used for Scenario 3.
A Māori worldview has informed the Process through which the Preferred Option was selected through their significant involvement in this process (Direction 2).
Watercare have taken the opportunity as part of this consenting process to improve the discharge quality on a staged basis over the proposed term of the consent as growth and development occur. The improved discharge quality provides, in turn protects the natural receiving environment over the term of the consent (Direction 3).
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Direction 4 seeks that Auckland’s infrastructure is future-proofed, the proposed discharges will ensure that the Army Bay WWTP is future-proofed for the maximum 35 year consenting term. The proposed upgrades set out in Section 3.4.4 further provide for the future-proofing of the Army Bay WWTP as they utilise the most advanced technology available to Watercare at this time. Additionally, the Army Bay WWTP site allows Watercare, in the event that it is deemed suitable, to further expand beyond the proposed 35 year due the land area available. Lastly, Watercare will propose a consent condition that provides for regular technology reviews that may identify options to further future-proof the Army Bay WWTP.
Focus area 3 seek to fully account for the past and future impacts of growth. In this regard Watercare have been guided by the Auckland Council ART Growth Model v i11 to ensure that the proposed discharges are able to service population growth in the service areas, and that the proposed upgrades to the Army Bay WWTP are also able to cater for this growth. Further, to account for the past and future impacts, Watercare plan to progressively upgrade the transmission network, as set out in Section 4.2.
8.4 SECTION 105 – MATTERS RELEVANT TO DISCHARGE APPLICATIONS
In addition to the matters which a consent authority must have regard to under s104, s105 sets out additional matters which must be considered when considering discharge applications. Section 105(1) states:
105 Matters relevant to certain applications
If an application is for a discharge permit or coastal permit to do something that would contravene section 15 or section 15B, the consent authority must, in addition to the matters in section 104(1), have regard to—
(a) the nature of the discharge and the sensitivity of the receiving environment to adverse effects; and
(b) the applicant's reasons for the proposed choice; and
(c) any possible alternative methods of discharge, including discharge into any other receiving environment
These matters are addressed in Sections 2 and 4 of this AEE.
The proposed upgrades of the Army Bay WWTP to provide for population growth take into account the nature of the discharge and the sensitivity of the receiving environment by providing an immediate improvement in the quality of the treated wastewater being discharged. Throughout the consent term the Army Bay WWTP will produce a treated wastewater quality that minimises the potential for adverse effects on the receiving environment.
The effects of the discharge of treated wastewater to the Whangaparaoa Passage has been assessed on the basis of a figure higher than the maximum modelled population during the
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consent term (190,000 PE compared to 188,500 PE forecast), and therefore the conclusions represent a conservative effects assessment. Therefore, given that:
• The effects will be minimised to the extent practicable:
• The need for an improved wastewater service for the current and future service area;
• The significant increase population based on the modelled population growth beyond the current service area; and
• The recent investment in the discharge pipeline,
the continued discharge of wastewater to the receiving coastal environment into the Whangaparaoa Peninsula is considered to be appropriate.
Overall, the Project provides an appropriate option for both short and long-term discharge in terms of the requirements of s105 of the RMA.
8.5 SECTION 107 – RESTRICTIONS TO GRANT CERTAIN DISCHARGE PERMITS
Section 107(1)(b) of the RMA places restrictions on a consenting authorities’ ability to grant certain discharge permits. It states:
107 Restriction on grant of certain discharge permits
(1) Except as provided in subsection (2), a consent authority shall not grant a discharge permit or a coastal permit to do something that would otherwise contravene section 15 or section 15A allowing—
(a) the discharge of a contaminant or water into water; or
(b) a discharge of a contaminant onto or into land in circumstances which may result in that contaminant (or any other contaminant emanating as a result of natural processes from that contaminant) entering water; or
(ba) the dumping in the coastal marine area from any ship, aircraft, or offshore installation of any waste or other matter that is a contaminant,—
if, after reasonable mixing, the contaminant or water discharged (either by itself or in combination with the same, similar, or other contaminants or water), is likely to give rise to all or any of the following effects in the receiving waters:
(c) the production of any conspicuous oil or grease films, scums or foams, or floatable or suspended materials:
(d) any conspicuous change in the colour or visual clarity:
(e) any emission of objectionable odour:
(f) the rendering of fresh water unsuitable for consumption by farm animals:
(g) any significant adverse effects on aquatic life.
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The proposed discharges of treated wastewater to the coastal environment will not result in any of the effects outlined in (c) – (g) at any time regardless of any mixing that may occur follow the discharge.
8.6 PART 2 MATTERS
The Court of Appeal has recently confirmed (in the R J Davidson Family Trust v Marlborough District Council decision) that when undertaking the section 104 evaluation the Council “must have regard to the provisions of Part 2 when it is appropriate to do so”. In this situation, given that the Unitary Plan has only recently been made operative (so it contains provisions prepared having regard to Part 2 and a coherent set of policies to achieve clear environmental outcomes) and does not add anything to the evaluative exercise, it is not considered necessary to undertake an assessment of the proposal against Part 2.
However, for completeness, this AEE provides a brief assessment which concludes that the application satisfies Part 2 of the RMA.
The purpose of the RMA is to promote the sustainable management of natural and physical resources. In this regard, the Project will provide for the operation of the Army Bay WWTP and discharge of wastewater for the 35 year consent term, and provide for the social, economic, and cultural wellbeing of the current and future people and communities served by the Army Bay WWTP.
The discharge of treated wastewater, and of contaminants to air from the Army Bay WWTP will not affect the safeguarding of the life-supporting capacity of air, water, soil and ecosystems. Likewise, Sections 5 and 6 of this AEE provide details on the measures proposed by Watercare to avoid, remedy or mitigate the actual and potential effects of the project on the environment and to manage effects on the wellbeing of people in accordance with section 5 of the RMA.
With respect to the key matters in sections 6, 7 and 8 of the RMA, the following points are pertinent:
• Appropriate consideration has been given to the discharge point in locating it outside of area of outstanding and high natural character, and SEAs, such that these values around the Whangaparaoa Peninsula will be preserved (sections 6a and 6c);
• The intrinsic values of the Hauraki Gulf and Whangaparaoa Passage ecosystems have been had particular regard to in setting the discharge volume and concentrations, such that the discharge of treated wastewater as set out in Section 3 is not able to be detected beyond 100 m of the outfall point (section 6(d)); and
• The relationship of Maori and their culture and traditions has been considered through the extensive consultation undertaken with Mana Whenua parties (sections 6(e) and 7(a)).
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Overall, and based on the technical assessments that have been commissioned by Watercare, it is considered that the discharges will be consistent with the sustainable management of natural and physical resources in accordance with Part 2 of the RMA (noting that Part 2 of the RMA is not being explicitly relied upon given the full coverage of relevant resource management issues provided in the Unitary Plan ).
8.7 SUMMARY
After considering all those matters relevant under Part 2 and s104, 105 and 107, granting the resource consents with appropriate conditions consistent with those applicable to the existing Watercare consents for the discharges would promote the purpose of the Act and would constitute sustainable management of natural and physical resources for the following reasons:
• It allows the use of natural and physical resources in a way which enable people and the community to provide for their social, cultural and economic wellbeing;
• It sustains the potential of natural and physical resources (excluding minerals) to meet the reasonably foreseeable needs of future generations;
• It safeguards the life-supporting capacity of air, water and soil, and ensures that adverse effects are appropriately avoided, remedied or mitigated; and
• It is demonstrably consistent with the relevant planning documents, including the NZCPS and the Unitary Plan.
The Project will meet the municipal wastewater needs of the local area has significant and have demonstrable positive effects in terms of sustaining the social and economic wellbeing of the community. Any adverse effects are appropriately avoided, remedied or mitigated and can be appropriately managed through the implementation of consent conditions.
Overall, it is considered that the granting of the resource consents, subject to the imposition of appropriate conditions, would promote the sustainable management of natural and physical resources and ensure that adverse effects on the environment are less than minor and / or appropriately avoided, remedied or mitigated.
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9. CONCLUDING STATEMENT
Watercare are seeking resource consent for the discharge of treated wastewater to the Whangaparaoa Passage and discharge to air from the Army Bay WWTP for a 35 year term, and land use consents to enable vegetation removal and land disturbance required to upgrade the Army Bay WWTP. The Army Bay WWTP will continue to service the communities of Whangaparaoa, Orewa and Silverdale, and also serve the communities of, Hatfields, Wainui, Dairy Flat, Stillwater, Okura Bush and Redvale as development in these areas occurs.
This AEE, supported by Volume 2, sets out in considerable detail how the Army Bay WWTP will be progressively upgraded to align with population growth over the proposed 35 year consent term.
The actual and potential effects associated with the discharge of wastewater to the Whangaparaoa Passage and discharge to air from the Army Bay WWTP have been considered in accordance with sections 104, 105 and 107 of the RMA. It is concluded that any potential adverse effects generated by the discharges will be appropriately avoided, remedied or mitigated such that they are limited in scale and extent and because of the rapid dilution and dispersion at this site combined with an improved level of treatment there will not be any detectable or ecologically significant change in the receiving environment. The discharges have also been assessed to be consistent with the relevant objectives and policies of the Unitary Plan.
Watercare is grateful for the input of stakeholder feedback into the process thus far, and records its commitment to ongoing consultation during the period when the resource consents are being considered by the Auckland Council and once resource consents are granted and being implemented.
Overall, it is considered that reconsenting the Army Bay WWTP to provide for the ongoing discharges to air and the coastal environment, will be consistent with the purpose of the RMA and that there are no impediments to the grant of the resource consents sought by Watercare.
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