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Resource Consent Application

WCC’s Western Wellington Wastewater Treatment Plant (WWTP) Main Outfall Pipeline (Karori Stream to Makara Coast)

Karori Stream Main Outfall Pipeline Maintenance – Global Consent

Prepared for: Wellington Water

On behalf of Wellington City Council

October 2015

Cardno Ref: NZ01-14121 Wellington Water Ref: PO 0000008830

Resource Consent Application Karori Stream Main Outfall Pipeline Maintenance – Global Consent

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Contact Information Cardno Limited Trading as Cardno (NZ) Limited Company No: 036749 (Wellington / Head Office) 25 Victoria Street, Petone, Lower Hutt 5012 PO Box 38-098, Wellington Mail Centre, Petone Lower Hutt 5045, New Zealand Telephone: (04) 478-0342 International: +64-4 478-0342 [email protected] www.cardno.com

Document Information Prepared for Wellington City Council Project Name Karori Stream Main

Outfall Pipeline Maintenance – Global Consent

File Reference NZ0114121-PL-RP001 Global RC app-Karori MOP Maintenance-FINAL 5B Oct 27-v5-rfs.docx

Project Reference NZ01-14121 Date October 2015

Document Control

Vers

ion Date Description Author

Initials Author (Signature)

Reviewer

1 30/06/2014 Draft RC Application for Client Comment JKG 1a 16/07/2014 Draft RC Application for Client Comment JKG 1b 07/08/2014 Final Draft RC Application for client comment JKG 1c 19/08/2014 Revisions made after client input JKG 1d 25/08/2014 As above JKG 1e 03/10/2014 Final approved by client – report date changed JKG 1f 22/10/2014 Final approved by client after further input by

client colleagues – report date changed JKG Anna Hector

2 15/04/2015 Draft – Full Revision following GWRC and landowner consultation meetings

JKG

3 25/6/15 Draft for further consultation with GWRC, order of sections amended and some deleted or reduced, added methodology for fish rescue.

JKG Anna Hector/GWRC

4 16/8/15 Draft for further consultation – DOC Report dates amended, updated frequency of works to identify short duration in active flows.

JKG Anna Hector

5 24/8/15 Draft for further consultation – Landowners & DOC - Report dates amended, updated fish rescue following DOC and GWRC Comments.

JKG Anna Hector

5A 05/10/2015 Final (v5) Removed draft comments – for lodgement.

JKG Anna Hector

5B 27/10/15 Updated legal road and ownership JKG Anna Hector

© Cardno 2012. Copyright in the whole and every part of this document

belongs to Cardno and may not be used, sold, transferred, copied or reproduced in whole or in part in any manner or form or in or on any media to any person other than by agreement with Cardno.

This document is produced by Cardno solely for the benefit and use by the client in accordance with the terms of the engagement. Cardno does not and shall not assume any responsibility or liability whatsoever to any third party arising out of any use or reliance by any third party on the content of this document.


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Quick Reference Summary Applicant: Wellington City Council (C/- Wellington Water Limited)

To: Greater Wellington Regional Council (GWRC)

Consents Sought: Water Permit and Land Use Consent under Rules 16 and 49 of the Regional Freshwater Plan for diversions (mostly minor), works and structures in the bed of a stream (Refer Section 4.0). The proposal is a discretionary activity.

Location: The length of the Main Outfall Pipeline (MOP) between the Wellington City Council‘s Western Wastewater Treatment Plant (WWTP) and the pipe outfall at the mouth of the Karori Stream at Makara on Wellington’s South Coast.

Refer Location Plan, Addresses and Legal Descriptions on following pages.

The Proposal: Karori Stream Main Outfall Pipeline Maintenance – Global Consent.

This application seeks a “global resource consent” to enable Wellington Water’s contractors (on behalf of Wellington City Council (WCC)) to carry out maintenance and repairs for planned and unplanned work (including emergency works) along the length of the MOP where those works are not provided for under the Regional Freshwater Plan or existing consents.

The proposed work is required to ensure the ongoing integrity of the pipeline – and is a specific requirement of one of the existing discharge permits for the WWTP (Discharge Permit WGN060283 [25226]), along with regular inspections to identify repairs and maintenance issues. Unfortunately the consent does not also permit maintenance and repair works to be undertaken where they involve works/structures in the bed of the stream – refer summary comments under “Background” heading on following page.

The proposed repairs and maintenance issues need to be addressed as and when they occur, following inspections, and will be subject to a Management & Monitoring Plan (MMP) – attached for approval with this application.

This application and the attached MMP set out the types of works for different parts of the pipeline and the methodologies and environmental protection measures that would be employed in each instance. Depending on what is observed during routine investigations of the pipeline, typical maintenance and repairs to be taken in and around the bed of the Karori Stream will include:

• Clearance of slip or flood debris (including fallen trees that have come down with slips);

• Repairing scoured sections of streambed and banks affecting the pipeline stability;

• Repairs to fords/river crossings;

• Disturbance and redistribution of bed material (including deposition of redistributed material) on the bed of the stream to

(i) Create stable access and works areas for machinery to safely access the pipeline; or

(ii) Divert scouring flows away from the pipeline or works areas (i.e. temporary and/or permanent diversions).

It is expected that this work will only be required 2-3 times a year (on average). The short term, temporary work can also be timed and managed through good practices to ensure negligible adverse effects on the stream environment (in particular water quality and freshwater aquatic habitat). The proposed works will only affect a relatively short section of the stream in each instance, and, unless it is unavoidable, take place in the dry bed as far as practicable. The actual and potential effects of the proposed works are limited to disturbance of the bed and banks of the stream and potential release of sediment and effects on freshwater aquatic habitat. No new structures are proposed, but the application includes reference to structures in the event replacement of existing pipeline structures is required. The benefits of the proposed work are the reduced risk of leaks of treated wastewater to the stream and the related impacts on the stream environment.


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Background

Discharge Permit [25226] referenced above is one of a suite of consents issued to Wellington City Council (GWRC reference: WGN060283 [25226], [25227], [25228], [25229] and [25230]) in 2010. These permit the discharge of fully (tertiary) treated effluent (by UV disinfected, secondary biological treatment) from the coastal outfall structure as well as air discharges of odour from the WWTP. They also allow for emergency discharges of fully treated effluent to the Karori Stream and milli-screened/settled effluent at the outfall in times of heavy rainfall.

Discharge Permit [25226] specifically acknowledges the age and condition of the approximately 6.2km pipeline, which was constructed in 1934, and includes conditions which require regular inspections, maintenance and reporting, and replacement of the 80 year old pipeline by 2023.

However, despite this clear direction in the consent, and the ability to provide for such direction in a bundle of consents of this type, formal permission to undertake those essential works was not included in the WGN060283 consent package. As a result, the consent holder and their representatives have been required to make ad hoc applications on a case by case basis with associated delays and costs.

This application for a Global Consent has been prepared to improve efficiency of consent administration for the Consent Holder and reduce associated delays and costs.

The approach presented for reporting is consistent with the reporting approach provided for in the existing consents and does not require a change of existing consent conditions.

Contact Details:

Address for Service: Invoicing Address:

Wellington City Council C/- Cardno PO Box 38-098 Wellington Mail Centre, Petone LOWER HUTT 5045 Attention: Jenny Grimmett, Consultant Planner Tel: (029) 200-3057 Email: [email protected] (Down to Earth Planning Ltd)

Wellington City Council C/- Wellington Water Ltd Private Bag 39804 Wellington Mail Centre, Petone LOWER HUTT 5045 Attention: Anna Hector Tel: (027) 285-6040 Email: [email protected]

Key Abbreviations used in this Report

AEE Assessment of Effects on the Environment

GWRC Greater Wellington Regional Council

MOP Main Outfall Pipeline

MMP Management & Monitoring Plan

RFP Regional Freshwater Plan

RMA Resource Management Act 1991

WCC Wellington City Council

WWTP Wellington City Council’s Western Wastewater Treatment Plant


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Location Information

This MOP is shown approximately as a red line in the aerial image (Figure 1-1) and Ownership Location Plan (Figure 1-2) below.

The pipeline from Wellington City Council’s Western Wastewater Treatment Plant (WWTP) and extends to the mouth of the Karori Stream on Wellington’s South Coast.

It follows the Karori Stream and is largely parallel with a forestry track formation that extends south from the end of the formed public road.

Aerial Location Plan – Annotated Extract from Google Earth Online Maps Figure 1-1

The Ownership Location Plan (Figure 1-2) shows the pipeline route in red, with land parcels coloured to depict landownership in vicinity of the pipeline and/or areas required for access to it.

Ownership Location Plan Figure 1-2– Provided by Wellington Water

Section 2 provides more detail on the stream and ownership of adjacent land.

Figure 1-2 is also attached in A4 format at Appendix C.


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Table of Contents Quick Reference Summary ii

1. Introduction 1 1.1 Introduction 1 1.2 Summary of Consents Required 1

2. Site Description 2 2.1 Overview 2 2.2 Ownership, Address & Legal Description 2 2.3 Physical Description 2 2.4 Access 7

3. Background 8 3.1 Overview of WCC’s Western Wastewater Treatment Plant Operations 8 3.2 Existing Consents 9

4. Proposal 10 4.1 Reasons for Seeking Global Resource Consents for Repairs & Maintenance 10 4.2 Overview of Proposed Maintenance & Repairs Works 10 4.3 Clearance of Flood or Slip Debris 11 4.4 Deposition of Gravel to Address / Repair Scour 11 4.5 Diversions 11 4.6 Works in the Streambed 13 4.7 Frequency of Inspections and Maintenance/Repair Works 14 4.8 Ecological Considerations 14 4.9 Erosion and Sediment Controls 18 4.10 Proposed Management & Monitoring Plan (MMP) 19 4.11 Duration of Consent 21

5. Regional Plan Assessment 22 5.1 Regional Freshwater Plan 22 5.2 Discretionary Activity Status 22 5.3 Regional Plan Objectives and Policies 22

6. Assessment of Effects on the Environment 27 6.1 Relevant AEE Assessment Criteria 27 6.2 Existing Stream Environmental Values 27 6.3 Water Quality 31 6.4 Ecological Effects 32 6.5 Flooding Effects 33 6.6 Erosion & Scour 33


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6.7 Mitigation and Monitoring Measures 34 6.8 Positive Effects 34 6.9 Overall Effects of Proposal 35

7. Consultation 36

8. Statutory Assessment 38 8.1 Overview 38 8.2 Part 2 of the Resource Management Act 1991 38 8.3 Section 104 39 8.4 Notification and Affected Persons Assessment 41

9. Summary & Conclusions 42

Figures Aerial Location Plan – Annotated Extract from Google Earth Online Maps ........ iv Figure 1-1 Ownership Location Plan – Provided by Wellington Water ................................. iv Figure 1-2 Summary of Access to Pipeline (Plan provided by Wellington Water) ................ 3 Figure 1-3 A section of pipeline encased in concrete with deep pool below (2400m) .......... 4 Figure 1-4 A section of Pipe Bridge No. 2 (before and after repair works) ........................... 4 Figure 1-5 A section of Pipe Bridge No. 2 (900m-1500m) .................................................... 5 Figure 1-6 Example of risk to pipeline from slips above stream, some of which dislodge Figure 1-7

trees (pipeline is out of view) ............................................................................... 5 View of Karori Stream showing braided channel formation (pipeline out of view)Figure 1-8

6 Views of Pipe Bridge No. 2 Scouring Examples (900-1500m) ............................ 6 Figure 1-9 View of Karori Stream showing diversion works to protect pipeline .................. 7 Figure 1-10 The Karori Wastewater Scheme ....................................................................... 8 Figure 1-11 Location of Diversions A and B undertaken in 2009 on the Karori Stream to Figure 1-12

protect the MOP .............................................................................................. 12 Diversion Works Completed in 2009 (Area A) ................................................. 12 Figure 1-13

Appendices APPENDIX A: Management & Monitoring Plan

APPENDIX B: Computer Freehold Registers (Title Documents)

APPENDIX C: A4 Format Copy of Figures 1-2 and 1-3 – Summary Access Plan and Ownership Plan

APPENDIX D: Suggested Conditions

APPENDIX E: Consultation Information


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1. Introduction 1.1 Introduction Pursuant to section 88 of the Resource Management Act 1991 (the Act), Wellington City Council (C/- Wellington Water) applies to Greater Wellington Regional Council for a global resource consent to undertake planned and unplanned ‘in-stream” repairs and maintenance activities along Wellington City Council’s Western Wastewater Treatment Plant Main Outfall Pipeline (MOP). The pipeline runs between the Treatment Plant (WWTP) and the mouth of the Karori Stream.

This application has been prepared in accordance with Form 9 and Schedule 4 of the Act, and incorporates all information required by those documents.

Wellington Water acts on behalf of Wellington City Council (WCC, the owner of the WWTP and MOP infrastructure) and is responsible for the ongoing management and maintenance of the infrastructure. This application has been prepared to enable Wellington Water (and its contractors) to undertake its responsibilities for the MOP and, in doing so, address the associated requirements of existing consent WGN 060283 [25226] (Discharge Permit for the MOP). This will not require a change of conditions to the existing consents.

The proposed “in-stream” maintenance works include: clearance of gravels and slip or flood debris, deposition of gravel, river crossings, construction of safe access and works areas, disturbance of bed material or deposition of material on the bed of the stream during the works, and diversions using redistributed material to keep flows away from structures and works areas. All activities will be undertaken in accordance with methodologies and environmental protection measures set out in a Management & Monitoring Plan (MMP).

This application solely relates to the existing pipeline until it is fully replaced by a new pipeline. Resource Consent [25226] requires a new pipeline to have been constructed and commissioned by 31 December 2023 (via a separate future consent process).

Descriptions of the Karori Stream environments (the site) where works are proposed are provided, as well as details the proposed repairs and maintenance works and methodologies for undertaking them in different parts of the Karori stream environment.

Sufficient information has been provided to ensure that any person can determine the likely outcome of the proposal, any adverse environmental effects that may arise, solutions to avoid, remedy or mitigate these effects on the environment, and suggested consent conditions.

The information contained in this application demonstrates the proposed works are appropriate for the locations proposed (based on timing of works and methods involved) and will contribute positively to the ongoing sustainable management of Wellington City’s public wastewater infrastructure. In this respect, the proposal balances the competing responsibilities of the applicant to ensure the ongoing health and safety of Wellington’s community and protection of relevant natural and physical environment values.

1.2 Summary of Consents Required As set out in Section 4, the proposal requires a Water Permit and a Land Use Consent under Rules 16 and 49 of the Regional Freshwater Plan for diversions, works and structures in the bed of a watercourse. The proposal is a discretionary activity overall. No consents from other authorities are required and there are no applicable National Environmental Standards.


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2. Site Description 2.1 Overview The application site comprises all land required to access and maintain/repair the Wellington City Council’s Western Wastewater Treatment Plant (WWTP) Main Outfall Pipeline (MOP).

This includes land either side of the Karori Stream between the WWTP in South Karori and its mouth at Makara on Wellington’s South Coast, as well as land required for vehicle and equipment access from legal roads to the different parts of the MOP within and beside the stream channel. The flows within the Karori Stream are also affected by the proposal fro time to time when it is not possible to work “in the dry”.

2.2 Ownership, Address & Legal Description Details of the landowners who provide access over their land to the pipeline are set out in the table below along with land owned by the Applicant. Figure 1-3 shows these properties.

Registered Landowner Legal Description & Title Reference Address

Wellington City Council

(The Applicant)

Section 1 SO 37211

WN46C/762

WWTP Site, South Karori Road

Erin Go Bragh Limited (Directors: ME & JM Warren & R Downes)

Lots 2 & 3 DP 422854

489165

509 South Makara Road

Clement Stephen & Patricia Anne Griffiths

Lot 2 DP 414390

453964

555, 567 South Makara Road

NZ Forestry Group Limited

(*Kinnoull Station)

Lot 1 and Pt Lot 20 DP 414390, Lots 17 & 18 DP 366070

613806


Terawhiti Farming Company Limited

Secs 4 & 17 and Pt Secs 13-15, 19, 33 & 50 Terawhiti District, Lot 3 DP 5864, Lot 13 DP 366070

467/199, 321565, 267889


Copies of relevant title documents are attached at Appendix B, with a letter by Cardno dated 13 October 2015 covering the legal status of the access (as part may not be legal road).

Note: Land owned by NZ Forestry Group (* Kinnoull Station) includes 10 lifestyle blocks (Lots 3-12 for sale) and separately held streamside titles (Lots 1, 14 and 20 DP 425554).

2.3 Physical Description

The single 375mm diameter, concrete pipeline is approximately 6.2 kilometres long. The MOP largely follows the alignment of the Karori Stream and the non-public extension of South Makara Road to the coastal outfall structure. It passes through a varied environment, which ranges among steep sided, narrow gorges and open braided gravel channels.

The pipeline construction features pipe bridges that span parts of the stream, or burial in the stream banks, or encasement in concrete. It also passes through tunnels and areas clear of the stream. The pipe bridges located in the upper reaches of the stream are quite short


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structures. Two larger pipe bridges occur in areas further downstream (refer Figure 1-3). In these downstream locations gravel sometimes needs to be redistributed to protect the pipeline structure from stream flow impacts, scouring of the streambed around pipe-bridge foundations or the stream banks where the pipe is buried and can become unstable.

A track from the terminus of the public South Makara Road formation to the Outfall provides 4WD access (mainly over NZ Forestry Group Land) to the banks of the stream and the MOP. Walking-only access is available to the stream upstream from the terminus of South Makara Road (via Erin Go Bragh and WCC owned land) as indicated approximately on the access plan at Fig 1-3. Wellington Water has, however, advised that vehicle access to the upper sections of pipeline has sometimes been possible. Note: PC Avins’ land shown on the plan in pale blue is not required for access to the pipeline.

Summary of Access to Pipeline (Plan provided by Wellington Water) Figure 1-3


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The following photographs illustrate some of the range of forms the pipeline takes along the Karori Stream alignment and its relationship to the watercourse bed and banks.

A section of pipeline encased in Figure 1-4

concrete with deep pool below (2400m)

A section of Pipe Bridge No. 2 (before Figure 1-5and after repair works)

Figure 1-4 shows a section of pipeline encased in concrete with deep pool below, approximately 2400m upstream from the outfall.

Figure 1-5 shows a section of Pipe Bridge Number 2 before and after repair work, 900m-1500m upstream from the outfall. The repaired section has gravel mounted behind the support structures to protect them from erosion by stream flows.

Figure 1-6 shows another view of Pipe Bridge Number 2 in the area 900m-1500m upstream of the outfall.

Figure 1-7 shows the upper reaches of the stream where damage by falling trees has been a problem for the pipeline in the past (refer Figure 1-3 for location).

Figure 1-8 shows the lower reaches of stream nearer the coast (refer Figure 1-3 plan for location).

Figure 1-9 shows more examples of scouring on Pipe Bridge number 2 that require repairs, 900m-1500m upstream from the outfall.