C1 erosion and sediment control plan

Auckland City Rail Link In association with:

ENABLING WORKS CONTRACT 1 EROSION AND SEDIMENT CONTROL PLAN

Document ref: CRL-BTM-ENV-DOW-PLN-000287

Revision: 6 FINAL June 2016

COMMERCIAL IN CONFIDENCE Erosion and Sediment Control Plan

FINAL

Version history Rev.

Date

Version details

Prepared by

Reviewed by

1

December 2015

Draft for Auckland Transport Review

Costas Chryssafis

J Urquhart, P Roan

2

January 2016

Draft for CLG Review

Costas Chryssafis

R Jenkins

3

April 2016

Draft incorporating Auckland Council comments

Costas Chryssafis

J Urquhart, R Purdy

4

May 2016

Draft incorporating CLG comments

Costas Chryssafis

J Urquhart, P Roan, R Jenkins

5

May 2016

Draft for Auckland Transport Review

Costas Chryssafis

J Urquhart, P Roan

6

June 2016

Final

Costas Chryssafis

J Urquhart, P Roan, R Jenkins

Distribution Date

Version

Issued to

Quantity & type

Approved for the DSBJV by

21 December 2015

Draft

Auckland Transport for review

1x Electronic

D Burtenshaw

22 January 2016

Draft

Community Liaison Group

1 x Electronic

D Burtenshaw

13 May 2016

Draft

Community Liaison Group

1 x Electronic

D Burtenshaw

20 May 2016

Draft

Auckland Transport for review

1 x Electronic

D Burtenshaw

2 June 2016

Final

Auckland Transport

1x Electronic 1 x Hard copy

D Burtenshaw

This document remains the property of DSBJV. Its contents are confidential and shall not be reproduced, destroyed or given away without express, written permission of DSBJV. The electronic version of this document in FULCRUM on designated serves(s) is the Master Copy and is a controlled document. Unless specifically noted, thereon, other copies of this document are uncontrolled. p:\30850\30850.0500 planning\30850.0512 (erosion and sediment)\workingmaterial\dwp\escp\crl-btm-env-dow-pln-000287 escp -final 30 05 16.docx

Erosion and Sediment Control Plan

June 2016

Table of contents 1

2

3

4

5 6 7 8 9

Introduction 1.1 Purpose of the Erosion and Sediment Control Plan 1.2 Relevant Conditions 1.3 Sustainability 1.4 ESCP review and updates Project Description 2.1 Overview 2.2 Active Construction Zones 2.3 Construction Support Areas 2.4 Staging of construction works and duration 2.5 Construction aspects 2.5.1 Site establishment 2.5.2 Excavation 2.5.3 Backfill 2.6 Site geology and groundwater 2.7 Catchment boundaries

1 1 2 6 6 7 7 7 8 11 11 11 11 12 12 13

Erosion and Sediment Control Approach 3.1 Key principles and approaches 3.2 General erosion and sediment control measures Specific erosion and sediment control measures 4.1 General 4.2 Perimeter controls 4.3 Vehicle access 4.4 Dewatering of excavation 4.5 Treatment plant 4.6 High risk spillage areas 4.7 Extreme weather events 4.8 Construction stormwater management 4.9 Stockpile management 4.10 Kerbside management 4.11 Specific erosion and sediment control measures 4.12 Certification of sediment control devices 4.13 Modification to structural controls Monitoring and Maintenance Roles and Responsibilities Environmental Training 7.1 Project staff Complaints 8.1 Complaints response ESCP Review 9.1 ESCP Review 9.2 ESCP Updates

14 14 15 16 16 16 16 17 18 18 18 19 19 19 19 22 22 23 25 26 26 27 27 28 28 28

Appendix A :

ISCA Requirements

Appendix B :

Chemical Treatment Management Plan

Appendix C :

Staging Plans

Erosion and Sediment Control Plan

June 2016

Appendix D :

Drawings

Appendix E :

CLG comments

Erosion and Sediment Control Plan

June 2016

Glossary of terms Term

Definition

ACZ

Active Construction Zone

AC

Auckland Council

ARI

Annual Return Interval

AT

Auckland Transport

BTC

Britomart Transport Centre

CEMP

Construction Environmental Management Plan

CLG

Community Liaison Group

CPO

Former Chief Post Office building

CRL

City Rail Link

CSA

Construction Support Area

CTMP

Chemical Treatment Management Plan

ECBF

East Coast Bays Formation

ESCP

Erosion and Sediment Control Plan

DSBJV

Downer Soletanche Bachy Joint Venture

DWP

Delivery Work Plan

IS

Infrastructure Sustainability

ISCA

Infrastructure Sustainability Council of Australia

TSS

Total Suspended Solids

TP90

Auckland Council Technical Publication No. 90, Erosion & Sediment Control: Guidelines for Land Disturbing Activities in the Auckland Region

Erosion and Sediment Control Plan

June 2016

1

1

Introduction

The City Rail Link (CRL) project comprises the construction, operation and maintenance of a 3.4 km underground passenger railway, running between Britomart Station and the North Auckland Rail Line in the vicinity of Mt Eden station. The works relating to this Erosion and Sediment Control Plan (ESCP) constitute part of the enabling works for the CRL. The works (the Project) involve the construction of an extension to the existing passenger rail network from the current termination point within the Britomart Transport Centre (BTC), westwards underneath the former Chief Post Office building (CPO) and Lower Queen Street. The Project footprint is shown generally by the blue shaded area in Figure 1.1 below.

LEGEND CRL alignment BTC designation CRL designation C1 worksite

Figure 1.1: Project Footprint

1.1

Purpose of the Erosion and Sediment Control Plan

This ESCP has been prepared to manage all bulk earthworks to minimise any discharge of debris, soil, sediment or sediment-laden water beyond the construction site to either land and/or stormwater drainage systems.

The ESCP is required under Condition 45 of the CRL Britomart to Wyndham Street land use consent R/REG/2014/5430 and addresses the requirements of Conditions 46 to 62 of this consent. It also addresses Conditions 99 to 101 of discharge permit R/REG/2014/5436.

This ESCP outlines: Relevant resource consent conditions; Identification of active construction zones (ACZ) and construction support areas (CSA); Specific erosion and sediment controls to be implemented for each ACZ, along with the transport of spoil; ESCP measures to be implemented to manage any contaminated soils or ground water encountered; Monitoring and maintenance requirements; and Methods for managing complaints and complaint response procedures.

Erosion and Sediment Control Plan

June 2016

2 If required to assist in the settlement and capture of sediment during the construction works, a chemical treatment plant will be established on site. A Chemical Treatment Management Plan (CTMP) is attached as Appendix B of this ESCP to address the relevant resource consent conditions (specifically Conditions 48(f) and 50 -53) relating to the operation and management of the on-site chemical treatment plant.

This ESCP has been prepared by Tonkin & Taylor Ltd (T+T) for the Downer Soletanche Bachy Joint Venture (the Contractor – DSBJV) and forms part of the Construction Environmental Management Plan (CEMP) for the Project.

1.2

Relevant Conditions

Table 1.1 outlines the resource consent conditions relevant to this ESCP and where they are addressed in the document.

Table 1.1: Condition No.

Relevant resource consent conditions and section where addressed in the ESCP Condition

Relevant section of the ESCP Land Use Consent R/REG/2014/5430

Erosion and Sediment Control Plan (“ESCP”) 45

At least 20 working days prior to the commencement of construction, a finalised ESCP which provides for the management of all bulk earthworks to minimise any discharge of debris, soil, sediment or sediment-laden water beyond the site to either land and/or stormwater drainage systems shall be prepared and submitted to the Council (Team Leader Central Monitoring) for certification.

This document

46

No construction activity shall commence until certification from Council is provided.

1.3 and 9

47

The Consent Holder shall request the Council’s (Team Leader Central Monitoring) determination as to whether the ESCP can be certified, in writing, within 10 working days of receipt of the ESCP.

1.3 and 9

48

The ESCP shall include, but not be limited to, the following matters: a. Identification of construction zones and construction support areas; b. Specific erosion and sediment control works for each Active Construction Zone (location, dimensions, capacity supporting calculations and design drawings), which should be in line with Industry Best Practice that will meet or exceed the performance of measures detailed in Auckland Council Technical Publication No. 90, Erosion & Sediment Control: Guidelines for Land Disturbing Activities in the Auckland Region (TP90); c. Catchment boundaries; d. The timing and duration of construction and operation of control works (in relation to the staging and sequencing of bulk earthworks); e. Details relating to the management of exposed areas; f. Reference to the Chemical Treatment Management Plan and confirmation of ESC measures necessary to give effect to that plan; g. Reference to the Contaminated Soils Management Plan and confirmation of ESC measures necessary to give effect to that plan;

Erosion and Sediment Control Plan

2.2 and 2.3 4 and 4.11

2.7 2.4 2.5 4.5 and Appendix B 3 and 5 5, 6, 7 and 8

June 2016

3 Condition No.

Condition

Relevant section of the ESCP

h. Monitoring and maintenance requirements, including information on complaint investigation and response procedures, training, and roles and responsibilities.

49

Any Change to the ESCP shall be submitted to the Council (Team Leader Central Monitoring) for certification. No activity reliant upon a change to the ESCP can be undertaken until the change has been certified. The Consent Holder shall request the Council’s (Team Leader Central Monitoring) determination as to whether the proposed change can be certified, in writing, within 10 working days of submission of the change.

1.3 and 9

Chemical Treatment Management Plan (“CTMP”) 50

At least 20 working days prior to the commencement of construction, a CTMP which confirms the measures that will be taken to ensure that construction of the Project or Project Stage will be generally consistent with the Water Quality Assessment and the Industrial and Trade Activities Assessment prepared by Golder Associates (NZ) Limited, both dated December 2014 shall be submitted to Council (Team Leader Central Monitoring) for certification.

Appendix B

51

The Consent Holder shall request the Council’s (Team Leader Central Monitoring) determination as to whether the CTMP can be certified, in writing, within 10 working days of receipt of the CTMP.

Appendix B

52

The CTMP shall include, but not be limited to, the following matters: a. Specific design details of the chemical treatment system based on a batch dosing methodology for the site’s settlement tanks, including the potential for use of non-chemical flocculants (e.g. chitin based flocculants such as Haloklear); b. Monitoring, maintenance (including post-storm) and contingency programme (including a record sheet); c. Details of optimum dosage (including assumptions); d. Results of initial chemical treatment trial; e. A spill contingency plan; and f. Details of the person or bodies that will hold responsibility for the long term operation and maintenance of the chemical treatment system and the organisational structure which will support this system.

Appendix B

53

Any change to the CTMP shall be submitted to the Council (Team Leader Central Monitoring) for certification. No activity reliant upon a change to the CTMP can be undertaken until the change has been certified. The Consent Holder shall request that the Council’s (Team Leader Central Monitoring) determination as to whether the proposed change can be certified, in writing, within 10 working days of submission of the change.

Appendix B

As-built Certification 54

Prior to construction (bulk earthworks) commencing, a certificate signed by a senior qualified person shall be submitted to the Council (Team Leader Central Monitoring) to certify that the erosion and sediment controls have been constructed in accordance with the certified ESCP(s) as required by Condition 45 of this consent.

4.12

55

Certified controls shall include diversion bunds, silt fences, and sumps.

The certification for these subsequent measures shall be supplied

3 and 4

Erosion and Sediment Control Plan

June 2016

4 Condition No.

Condition

Relevant section of the ESCP

immediately upon completion of construction of those measures.

Information supplied, if applicable, shall include: a. Contributing catchment area; b. Shape of structure (dimension of structure); c. Position of inlets/outlets; and d. Stabilisation of the structure General Performance Standards 56

The Consent Holder shall ensure that there shall be no deposition of earth, mud, dirt or debris on any road or footpath resulting from bulk earthworks on the subject site. In the event that such deposition does occur, it shall immediately be removed. In no instance shall roads or footpaths be washed down with water without appropriate erosion and sediment control measures in place to prevent contamination of the stormwater drainage system, watercourses or receiving waters.

3, 4.3, 4.9, 4.10 and 4.11

57

The operational effectiveness and efficiency of all erosion and sediment control measures specifically required as a condition of resource consent, including the certified ESCP referred to in Condition 45, shall be maintained throughout the duration of bulk earthworks, or until the Project site is permanently stabilised against erosion.

3, 4, 5 and 6

58

The site shall be progressively stabilised against erosion at all stages of earthworks activity, and shall be sequenced to minimise the discharge of contaminants to groundwater or surface water.

3

59

The Consent Holder shall ensure that the erosion and sediment control measures shall be constructed and maintained in accordance with Auckland Council’s Technical Publication 90: Erosion and Sediment Control Guidelines for Soil Disturbing Activities in the Auckland Region, and any amendments to this document, except where a higher standard is detailed in the documents referred to in conditions above, in which case the higher standard shall apply.

3

60

Sediment control measures shall be inspected on a weekly basis and after a significant storm event to ensure effective operation. In the event that a discharge of debris, soil, silt, sediment or sediment-laden water occurs, the activity which resulted in the discharge shall cease immediately and the discharge shall be mitigated and/or rectified to the satisfaction of the Council (Team Leader Central Monitoring).

5

61

The Consent Holder shall ensure that all material removed from or delivered to the Project site shall be covered during transportation.

2.5.2

62

Upon completion or abandonment of bulk earthworks on the Project site all areas of bare earth shall be permanently stablished against erosion to the satisfaction of the Council (Team Leader Central Monitoring).

4.11

Washwater and Wastewater Discharges – Discharge Permit R/REG/2014/5436 Structural Controls 99

The Consent Holder shall ensure that the following structural controls are constructed for the following catchment areas and designed requirements and they are completed prior to discharges commencing from the site.

Appendix B1

Settlement tanks are located in Construction Support Area A (Galway Street) as opposed to Construction Support Area B / Construction Support Area 2 (Lower Queen Street) in order to create a more efficient CSA layout 11

Erosion and Sediment Control Plan

June 2016

5 Condition No.

100

Condition

Relevant section of the ESCP

Works

Device catchment area

Design requirements

Settlement Tanks (2X 12,000l tanks), located in CSAs 2 and 4

All ACZs

Discharge levels as per monitoring Condition 101

Bunding Environmentally Hazardous Substances

As required

110% of largest container

In the event that any minor modifications to the structural controls system are required, the following information shall be provided to Council: a. Plans and drawings outlining the details of the modifications; and b. Supporting information that details how the proposal does not affect the capacity or performance of stormwater management systems.

All information shall be submitted to, and the proposed modifications certified by the Council (Team Leader Central Monitoring), prior to implementation.

4.13 and Appendix B

Discharge Monitoring 101

Within 30 days of the installation of the water treatment system, and prior to operation, a discharge monitoring programme, to assess the ongoing adequacy of all management practices, shall be developed and submitted to the Council (Team Leader Central Monitoring) for certification. The monitoring programme shall include, but not be limited to: a. Sampling location for final discharge form the site(s); b. Sampling locations on site (i.e. swale inlets, outlets etc.); c. Methods and procedures for discharge sampling on a quarterly basis; d. Monitoring parameters for analysis, which shall include: Daily Turbidity (NTU) pH Weekly Total Suspended Solids mg/L Copper (total) mg/L Zinc (total) mg/L Lead (total) mg/L Total Petroleum Hydrocarbons mg/L e. Identified trigger levels for each of the above parameters. These trigger levels shall be developed with reference to the ANZECC Guidelines for water quality where applicable; and f. The methods and procedures for investigating and reporting stormwater discharge monitoring results to the Council (Team Leader Central Monitoring).

Erosion and Sediment Control Plan

5 and Appendix B

June 2016

6

1.3

Sustainability

AT is seeking an Infrastructure Sustainability Council of Australia (ISCA) Infrastructure Sustainability (IS) Rating. Further details can be found in the Project CEMP and Sustainability Rating Management Plan. Project sustainability requirements that relate directly to this ESCP are included in Appendix A. These requirements are imbedded within this ESCP to ensure that sustainability is a key focus and ‘the way we do things’.

In some cases the IS requirements and sustainability goals enhance the designation requirements.

1.4

ESCP review and updates

This ESCP is a live document that will be reviewed and updated if needed during the course of the Project to reflect material changes associated with construction techniques or the natural environment. Any material changes to the ESCP must be certified by Auckland Council (AC) prior to any on-site activity reliant upon the change commencing. A formal review process is described in Section 9 of this ESCP.

Erosion and Sediment Control Plan

June 2016

7

2

Project Description

2.1

Overview

The Project involves the construction of an extension to the existing passenger rail network from the current termination point within the BTC, westwards underneath the CPO and Lower Queen Street.

Separate works are being undertaken to continue the CRL tunnels from this point under the Downtown Shopping Centre site (which is to be redeveloped by Precinct Properties), and then up Albert Street.

Significant works beneath the CPO will be undertaken, with the construction of two new rail tunnels extending westwards beneath the basement floor level. In Lower Queen Street, sheet piling will be extended across the road corridor, excavation undertaken to form the tunnels followed by reinstatement of the road corridor following the completion of works. During construction, existing ticketing and retail functions and pedestrian access to the station will be accommodated in Station Plaza, at the rear of the CPO building.

Surface works will also be required in QEII Square associated with the Downtown Shopping Centre redevelopment, including construction of the CRL rail tunnels beneath this site (Precinct Properties scope of work).

All of the land within the Project area (at the surface) has been previously disturbed.

A detailed description of the construction works is provided in the CEMP.

2.2

Active Construction Zones

The Project will be divided into four discrete ACZ as shown in Figure 2.1.

Figure 2.1: Active Construction Zones

The referencing of Project ACZs adopted in this ESCP reflects that of the BTC designation in order to ensure consistency across all Project Delivery Work Plans and Environmental Management Plans. It

Erosion and Sediment Control Plan

June 2016

8 is noted that under the resource consents, the Project area is separated into two larger ACZ’s – ACZ A (CPO) and ACZ B (Lower Queen Street) – refer to Figure 2.3.

A summary of the works required in the four ACZs is outlined in Table 2.1 Table 2.1:

Summary of key construction activities within each ACZ2

Active Construction Zone

Key construction activities

A

Britomart Station modifications Modification of existing platforms and track lines Installation of temporary access stairs, station entry and egress

B

Accommodation within Station Plaza Construction of temporary accommodation buildings and facilities and relocation of ticketing, staff facilities, public amenities, retail/kiosk areas from the CPO building Installation of services.

C

CPO Building Works Removal of the CPO fixtures and fittings, including the timber floor Saw cutting and demolition of the concrete ground floor in the main ticket hall and processing concrete for use as backfill later Installation of guide walls, diaphragm walls and underpinning structures to provide support for the CPO Soil excavation Construction of the base slab, walls and roof for the new rail tunnels Backfill excavation Reinstatement and fit out of CPO building

D

Lower Queen Street Bentonite plant located adjacent to the south west corner of the CPO building on Lower Queen Street Carry out piling and underpinning works Soil excavation Construct base slab, walls and roofs for new rail tunnels Backfill excavation Reinstatement of Lower Queen Street

2.3

Construction Support Areas

Three construction support areas (CSA) will be established to support the ACZs as outlined in Table 2.2 and shown on Figure 2.2.

The three CSAs will support the ACZs and provide for general activities, such as site offices and construction personnel amenities, machinery parking and storage, loading/unloading and temporary storage of construction materials, waste storage and collection. Although unlikely, temporary storage of excavated spoil may be required in unforeseen circumstances (for example, breakdown of construction plant). Any temporary stockpiles shall not exceed 24 m³ per ACZ3 and shall be appropriately covered as outlined in the Project Air Quality DWP (Appendix L of the CEMP).

2 3

Note these activities are not in order of programme In accordance with Condition 71(e) of discharge permit R/REG/2014/5437

Erosion and Sediment Control Plan

June 2016

9 All yards and construction areas will be fully fenced at the perimeter and made secure for the safety of the general public. Signage will be placed near the entrances of all construction yards that will include Project information, including the Project Hotline number.

All storage of material and equipment associated with the construction works will take place within the boundaries of the Project area.

Table 2.2:

Construction Support Areas

Construction Support Area

Location

Construction zone supported

Area

A

Galway Street

Supports temporary accommodation works in Station Plaza

400 m2

Material storage Crane location and access to CSA A Stormwater and groundwater treatment tanks

B

Lower Queen Street

Supports CPO and Lower Queen Street construction

3,500 m2

Bentonite treatment plant Jet grout pump and mixing plant Material storage

C

Tyler Street

Provides construction access to the CPO

400 m2

Temporary site office during Stage 1 of the Project Material storage Crane location and access for CSA C Main vehicle entrance to the CPO building

Erosion and Sediment Control Plan

Key Plant/Activities

June 2016

10

Figure 2.2: Construction Support Areas

Note: Blue hatched areas on Figure 2.2 show the areas of the Lower Queen Street that will be maintained as traffic lanes in order to provide vehicle access from Lower Queen Street to Tyler Street and Galway Street into Lower Queen Street The referencing of Project CSAs adopted in this ESCP reflects that of the BTC designation to ensure consistency across all Project Delivery Work Plans and Environmental Management Plans. It is noted that under the resource consents, the Project area is separated into two CSAs – CSA 1 and CSA 2 – refer to Figure 2.3.

Figure 2.3: Resource Consent ACZ and CSA referencing

Erosion and Sediment Control Plan

June 2016

11

2.4

Staging of construction works and duration

The staging and expected duration of the Project works are summarised in Table 2.3. The construction works programme is anticipated to commence in July 2016 and be completed by June 2020 – a duration of 48 months.

Table 2.3:

Staging of construction works

Stage and ACZ

Dates

Approximate Duration

Stage 1 / ACZ B – Temporary station access, construction of temporary accommodation in Station Plaza and streetscape works.

July 2016 to January 2017

7 months

Stage 2 / ACZ C – CPO building works, piling, removal of CPO ground floor

January to May 2017

4 months

Stage 3 / ACZ C and D – piling, CPO underpinning excavation, tunnel construction and backfilling.

May 2017 to March 2020

34 months

Stage 4 / ACZ A, B, C and D – Reinstatement & station fit out.

April to June 2020

3 months

Refer to the staging plans provided at Appendix C for further details on Project staging and the main construction activities in each stage.

2.5

Construction aspects

2.5.1

Site establishment

Site establishment activities will include site clearance, establishment of temporary accommodation buildings within Station Plaza to the rear of the BTC, ground preparation, and the establishment of erosion and sediment control measures prior to any construction activities occurring. Once the construction sites are established, stormwater runoff from impervious areas of the construction sites will be captured and treated according to this ESCP. Section 2.2 of the CEMP provides further details on site establishment and temporary accommodation works.

2.5.2

Excavation

Excavation of both Lower Queen Street and beneath the CPO will be conducted concurrently. The area of the proposed excavations will extend to approximately 14 – 16 m below ground level (bgl).

The length of the excavation in Lower Queen Street will be approximately 26-28 m from the edge of the CPO building across Lower Queen Street, with the width approximately 22 – 25 m along the CPO frontage. Approximately 20,000 m3 of material will be excavated from the Lower Queen Street and CPO excavations.

Lower Queen Street will be excavated using long-reach excavators at road level excavating between props, which will be lowered into the excavation and installed using a mobile crane. Final trimming and pump station excavation will be undertaken by a small excavator lowered into the trench, feeding a long-reach at road level. Spoil will be loaded directly onto truck and trailers, covered and transported from the site.

Excavation beneath the CPO will take place in two phases. Initially, excavation will be conducted from inside the building, with two excavators excavating each rail tunnel. The spoil from the northern tunnel will be loaded out onto six wheeler trucks backed into the CPO through the northwestern door. The southern tunnel spoil may be loaded onto a conveyor belt, which will be installed

Erosion and Sediment Control Plan

June 2016

12 through one of the existing pedestrian doors, or placed into waiting trucks. Spoil will be covered before being transported from the site.

Once the second level of struts have been installed within the CPO, the CPO excavators will be demobilised. Eight tonne excavators and tracked skid-steer loaders will be lowered into the excavation at the interface of the Lower Queen Street excavation and CPO. Working beneath the props, the excavators will progress eastwards beneath the CPO, feeding the tracked skid-steer loaders, which will move the material to long-reach excavators waiting on Lower Queen Street.

The expected earthwork volumes and areas for each ACZ are outlined in Table 2.4.

Table 2.4:

Earthwork volumes

ACZ

Earthwork volume (cut) m3

Earthwork volume (fill) m3

Earthwork area (exposed) m2

A

N/A

N/A

N/A

B

N/A

N/A

N/A

C

10,000

4,000

1,000

D

10,000

7,000

1,500

2.5.3

Backfill

Approximately 11, 000m³ of material will be required for the Project, primarily to backfill the CPO and Lower Queen Street excavations. Crushed concrete from the CPO internal ground floor demolition will be used as backfill, where practicable, in order to reduce the quantity of imported fill required.

In Lower Queen Street, backfill material will be placed over the tunnels by a loader at road level, spread and compacted by plant in the trench.

Within the CPO, the material will carted by skid-steer loader from the Lower Queen Street façade to the eastern end of the building, progressively filling towards Lower Queen Street.

Material will be compacted in layers as it is placed.

Props will be removed progressively as backfill progresses. The props will be re-used or recycled off site.

2.6

Site geology and groundwater

The geology of the Project area has been established by earlier investigations for the CRL Britomart to Wyndham Street enabling works. The general stratigraphic sequence comprises fill overlying Tauranga Group overlying East Coast Bays Formation (ECBF) within the Waitemata Group. A brief description of the stratigraphic units for the Project area is provided below: Fill – asphalt or concrete pavement underlain by granular basecourse and/or sub-base. Fill materials may comprise re-worked natural soils (silts, sands and gravels) or waste materials such as ash, clinker and demolition rubble.

Auckland Volcanic Field – the Albert Park Volcano, located east of Queen Street is close to the Britomart to Wyndham Street section of the CRL project.

Tauranga Group – alluvial and marine sediments comprising peat, mud, silt, sand and gravel.

ECBF – alternating sandstone and siltstone beds with a completely weathered (residual soil) upper surface.

Erosion and Sediment Control Plan

June 2016

13 The Waitemata aquifer is the dominant hydrogeological unit in the central and southern part of the Auckland Central Business District. Key aspects of the hydrogeological model for the Britomart to Wyndham Street enabling works are: Localised/perched groundwater heads in un-weathered ECBF and weathered ECBF of 1 to 2 m are recorded. Seasonal groundwater level variations are likely to be about 2 m and responses to rainfall events can result in a 0.4 m variation. The perched groundwater is not hydraulically connected to the underlying regional ECBF (lower) groundwater level.

The groundwater level in the Fill, Tauranga Group and ECBF in the reclaimed area is close to sea level and groundwater flow is north towards the harbour. The groundwater in the Fill is complex due to the mixture of materials present and is highly dynamic, being controlled principally by tidal effects close to the sea and the drainage-recharge influences of the stormwater drainage system. Together with other network utility service lines (many over a century old and potentially ‘leaky’), the backfill in these service trenches is considered to form rapid flow conduits for groundwater movement.

2.7

Catchment boundaries

Stormwater runoff will be controlled and managed throughout the Project. Only limited stormwater inflow into the cut and cover excavation within Lower Queen Street (ACZ D) is expected. The volume of stormwater inflow into this area will be reduced by the majority of the excavation in Lower Queen Street taking place under a canopy and with a barrier wall around the perimeter of excavations.

Excavations within the CPO (ACZ C) will be contained within the CPO building and hence not subject to external weather conditions. The total Project catchment area contributing to stormwater inflow into the excavations will be approximately 600 m2.

The catchment boundaries and associated information are shown on Figure 1 in Appendix D.

Erosion and Sediment Control Plan

June 2016

14

3

Erosion and Sediment Control Approach

3.1

Key principles and approaches

Erosion and sediment control measures will be implemented in order to minimise the extent of soil erosion and sediment yield from the Project site during the works. The erosion and sediment control measures will be designed, implemented and monitored in accordance with Auckland Council Technical Publication 90 (TP90) “Erosion and sediment control guidelines for land disturbing activities in the Auckland Region”. In some circumstances, and where appropriate, measures exceeding the requirements of TP90 will be used where there is a greater risk of erosion and sediment runoff effects associated with undertaking the works. All sediment control measures will be fully established within each ACZ before physical works commence in that area.

Key principles underpinning this ESCP include: Viewing the Project works holistically, such that all construction activities, and the full effects of these construction activities, are considered as a whole.

Implementing a team approach for design, implementation, maintenance and disestablishment of erosion and sediment control measures. This will ensure “ownership” of the erosion and sediment control measures and therefore better implementation and maintenance.

Undertaking pre-construction meetings for each specific package of works and having regular weekly meetings (toolbox meetings) on site with relevant personnel and AC officers.

Preparing a detailed schedule of construction activities, with monthly updates, and providing these to AC. Maintaining a register of control measures and “As Built” information to allow for quick referencing and understanding of erosion and sediment control measures.

Including both physical and non-physical elements within the methodologies to be employed such as: Pre-construction investigation and testing to confirm the nature of the ground materials and to identify the presence of any contamination.

Providing interceptors to minimise the ingress of rainfall and surface runoff into the construction zones and thus minimise the erosion and sediment generation process to be dealt with during construction.

Protecting the construction zones from flooding and ensuring that the protection measures do not lead to increased flood risk of adjacent properties.

Providing a sediment settling and retention device to manage and treat sediment laden water collected during construction and discharge it at an acceptable quality into the receiving environment4.

Isolating, treating and disposing of any contaminated materials encountered (refer also to the Project Contamination Delivery Work Plan).

Providing measures which prevent spillage from higher risk construction activities such as bentonite processing and concrete production areas.

Identifying and managing risk at high risk areas.

Responding to weather patterns.

Water quality in the receiving environment is outlined in Section 4.6.3 of the Auckland City Rail Link Britomart to Wyndham Water Quality Assessment dated December and prepared by Golder Associates 4

Erosion and Sediment Control Plan

June 2016

15 Ensuring construction workers are aware of the erosion and sediment controls employed and do not remove them without seeking appropriate approval.

3.2

General erosion and sediment control measures

The following general erosion and sediment control measures will be employed: Provide silt fences, silt capture at catchpits and bunding at surface works to prevent dirty water ingress into the public stormwater system. Silt capture at catchpits will be managed to ensure that it does not exacerbate flooding during rainfall events.

Provide bunding around excavations to a level above the design flood plain in order to protect the excavations from flood inundation via surface runoff and flood plains during extreme rainfall events, recognising that any inundation could flood the BTC and place the rail service at risk.

Undertaking as much work as possible “under roof� to limit the amount of water to be managed in the excavations.

Minimising groundwater ingress into the excavations.

Provision of a settling tank to receive water pumped from the excavations for settling and capturing sediment, enabling water of suitable quality to be discharged into the receiving stormwater drainage system.

Provision of assisted sediment settlement if required, using chemical or non-chemical flocculants, the latter being preferred if effective. A batch dosing methodology will be deployed.

The Project’s water quality discharge goal is consistent with standards set out in the Water Quality Assessment report prepared by Golder Associates (dated December 2014), namely, minimum water clarity of 10 cm measured with a black disk, TSS concentration of less than 50 g/m3 for 95% of the time, pH between 5 and 9, and no visible TPH (refer to CTMP in Appendix B for further details).

It is assumed that there will be no stormwater capacity limitations for discharging the treated water from the site.

All material removed from or delivered to the Project site shall be covered during transportation.

Stabilised entrance ways will be established at ingress and egress points of the site. Road vehicles carting to and from the site will remain on sealed accesses while within the site boundaries. The roads and footpaths will be cleaned regularly and maintained to ensure that they remain free from soil and material, which could be tracked off the site.

High risk spillage areas will be bunded for the containment and management of any spilled materials.

Any contaminated soils encountered will be managed as described in the Contamination Delivery Work Plan (DWP) provided at Appendix K to the CEMP. The general intent is to isolate any contaminated materials from the rest of the excavated materials and dispose of them as outlined in the Contamination DWP. Dust control measures will be applied to construction activities including stockpiles, concrete cutting, demolition work, earthmoving, general construction activities, and bentonite powder handling. Details of the measures to be implemented are outlined in the Project Air Quality DWP provided at Appendix L to the CEMP.

Erosion and Sediment Control Plan

June 2016

16

4

Specific erosion and sediment control measures

4.1

General

The erosion and sediment control measures that will be implemented for the Project are based on the principles outlined in Section 3.2. Table 4.3 in Section 4.11 of this ESCP outlines specific erosion and sediment control measures applicable to each construction activity and ACZ.

4.2

Perimeter controls

Perimeter controls will be provided for the works in ACZ D (Lower Queen Street). These will take the form of a barrier wall around the excavations (within the construction area), of sufficient height to provide flood protection against high return period rainfall events as well as keeping clean runoff out of the site. Given the importance of avoiding flooding of the rail service, protection against rainfall events with an Annual Return Interval (ARI) of at least 1 in 200 years will be adopted.

Council flood hazard maps show 1 in 100 year ARI flood depths of up to 0.2 m in the vicinity of the works in Lower Queen Street. The barrier wall will be no higher than 0.5 m. The barrier wall will be constructed with blockwork or reinforced concrete and bonded at its base to the road surface. A ramp will be constructed to allow vehicular access into and out of the site over the top of the wall.

Design checks will be made to confirm that the formation of the barrier wall will not create increased flood risk for adjacent properties.

In addition, a canopy will be constructed over most of the excavation area in Lower Queen Street in order to minimise the amount of rainfall to be managed within the excavations. The canopy will initially cover approximately 60% of the open excavation and increase to approximately 80-90% cover after the main excavations are completed. The critical case for exposed earthworks is therefore 500 m2 for ACZ D, i.e. 40% of the 1,500 m2 total earthwork area. If practicable, water will be collected from the canopy for reuse in the Project area.

With the barrier wall and canopy in place, diaphragm walls installed to significantly reduce the groundwater ingress, and subsurface work below the CPO contained within the building footprint, only limited volumes of water will need to be managed within the excavations. As such, the construction methodology minimises the ESCP measures required for the cut and cover excavation and tunnel construction.

4.3

Vehicle access

Vehicle access for the transport of excavated materials from the site and delivery of materials to the site will be via sealed access ramps on the northern and southern sides of the Lower Queen Street excavation (ACZ D). Vehicles transporting material to and from the site will not be passing over excavated ground.

The expected construction traffic volumes are outlined in Table 4.1

Erosion and Sediment Control Plan

June 2016

17 Table 4.1:

Expected construction traffic volumes

Construction Stage and ACZ

Light Vehicles Per Day

Trucks Per Day

Total Vehicles Per Day

Stage 1 (ACZ B) – Temporary western station access

30

4 to 10

34 - 40

Stage 2 (ACZ C) – CPO under pinning & tunnel excavation

40

20 to 35

60 – 75

Stage 3 (ACZ A and D) – Tunnel construction

40

20 to 35

60 – 75

Stage 4 (All ACZ) – Reinstatement & station fit out

30

4 to 10

34 - 40

4.4

Dewatering of excavation

The rainwater and groundwater inflow rates expected to enter the excavations within the Project area are summarised in Table 4.2.

Table 4.2:

Water inflow rates

Rainfall event annual return interval (ARI)

24 hour rainfall depth (mm)

Rainfall ingress in 24 hour rainfall event5 (m3)

Groundwater inflow6 (m3/day)

Total water ingress in 24 hours during design rainfall event + groundwater (m3)

1 in 2 year

76

45

250

295

1 in 5 year

99

60

250

310

1 in 20 year

145

90

250

340

1 in 100 year

188

110

250

360

No more than 5 m3/day of groundwater ingress is expected through the temporary perimeter cut-off walls. This means that the majority of the predicted groundwater ingress will be through the bottom of the excavations prior to casting of concrete base slabs for the new rail tunnels.

Excavations within the CPO and in Lower Queens Street will be sloped towards a low point on the eastern side of the Lower Queen Street excavations. A pump sump/sediment pit will be constructed at the drainage low point for the capture of coarse sediment before pumping to a treatment system at street level that will be located outside the south east corner of the CPO, adjacent to the glasshouse (within CSA A). The pump system will comprise two pumps in order to handle low and high inflows into the excavations.

5

Based on 600 m2 exposed excavation area in Lower Queen Street.

6

Based on predicted maximum short term tunnel inflow rates given in Table 10 of PDP groundwater effects assessment – Britomart to Wyndham report, December 2014. Of the amount shown, 84% (210 m3/day) is estimated to be contributed from the excavations within the CPO.

Erosion and Sediment Control Plan

June 2016

18

4.5

Treatment plant

A settlement based treatment plant will be located in CSA A, adjacent to the south east corner of the CPO building and next to the glasshouse (refer to Figure 2.2). The plant will include chemical treatment capability to assist the settlement process when required. A CTMP is provided in Appendix B of this ESCP and outlines the specific design of the treatment plant including: Treatment design flow; Header tank; Dosing system; High capacity lamella type proprietary settlement unit; Water reuse tank; Temporary storage tank; Monitoring of water quality; Spill contingency plan; and Responsibilities for the operation and maintenance of the CTP. The high capacity settlement unit will be located in CSA A in Galway Street and will receive and treat contaminated water from the excavations in ACZ C and ACZ D and from the supporting CSAs. The unit will have an effective settlement area of 50 m2, with a volume of approximately 7 m 3. It will be designed, with chemical dosing if necessary, to achieve an effluent discharge water quality complying with standards set out in resource consent condition 101. The temporary storage tank will be located beside the settlement unit and will receive water for recycling through the treatment plant if the effluent quality is unsatisfactory. The tank will have a volume of 35 m 3.

4.6

High risk spillage areas

High risk spillage areas within the construction site include: The bentonite treatment plant, located adjacent to the south west corner of the CPO building on Lower Queen Street; Jet Grouting Plant, located adjacent the north western corner of the CPO building on Lower Queen Street; and Other areas around the work site where concrete production is required.

Areas around these activities will be bunded as appropriate to prevent any spillages escaping from the site. The containment works will include collection sumps and possible pumps and storage tanks for transferring contaminated fluids to trucks for disposal off site at suitable facilities. Refer to the Industrial and Trade Activities Environmental Management Plan (ITA EMP) provided at Appendix N to the CEMP for more detail on the management of the above construction activities.

4.7

Extreme weather events

A large portion of the work will be contained within the CPO building or under the canopy that will be constructed over a large proportion of the works within Lower Queen Street. In addition, flood protection measures will be put in place around the perimeter of the Lower Queen Street works. As such, extreme weather events are not expected to influence the construction activity.

Contingency measures for the Project will address inundation of the excavations.

All erosion and sediment control devices will be inspected after a storm event to ensure they are still operating effectively.

Erosion and Sediment Control Plan

June 2016

19

4.8

Construction stormwater management

Once the Projects ACZs and CSAs are established, stormwater runoff from impervious areas will be captured and treated according to this ESCP. Design of the temporary stormwater management facilities for the yards will be provided to AC as they become available to comply with the relevant resource consent conditions.

4.9

Stockpile management

Only limited, temporary stockpiling of material will take place during construction of the Project.

Generally, excavated material will be sorted into contaminated material, managed fill and clean material and directly loaded on to trucks for disposal off site. Backfill material delivered to site will be placed directly in the backfill zones.

Any temporary stockpiles of excavated or construction materials will not exceed 24 m 3 of spoil at any one time in each ACZ in accordance with Condition 71(e) of the Projects discharge to air permit R/REG/2014/5437. Stockpiles will be managed to prevent sediment runoff or airborne dust from them by applying one or more of the following measures: Use of covers.

Light compaction of stockpile surfaces.

Light wetting for dust suppression.

Bunding.

Refer to the Project Air Quality DWP for further detail on the management of dust from any stockpiles.

4.10

Kerbside management

The Project includes kerbside management changes (including footpath widening) that will require cutting and laying of concrete along Tyler and Galway Streets.

Erosion and sediment controls measures to manage this activity will include: Dust management measures outlined in the Air Quality DWP. Continuous cleaning of kerbside and sidewalks.

Avoidance of placing materials and equipment on or near footpaths.

Effective reinstatement and site tidying.

4.11 Table 4.3:

Specific erosion and sediment control measures Construction activities and related erosion and sediment control approach

Construction Activity

Approx.

Duration

Specific ESC measure(s)

Stage 1 – Site establishment, temporary accommodation and streetscape works Site establishment and temporary site office

7 months

Install filter socks around plant storage yards.

Install and manage geotextile and filter socks under and around nearby stormwater catchpit grates in such a way as to avoid exacerbated flooding during rainfall events.

Stage 2– CPO building works

Erosion and Sediment Control Plan

June 2016

20 Construction Activity

Approx.

Duration

Specific ESC measure(s)

Removal of raised floor in former banking chamber Protection of heritage features in the CPO

Up to 3 months

Apply dust control measures specified in Air Quality DWP.

Saw cutting and demolition of CPO concrete ground floor Processing of concrete for backfill use

3 months

Apply appropriate dust control measures specified in the Air Quality DWP. Any water used for concrete saw cutting or from processing of existing concrete is to be collected and disposed of off-site.

Stage 3 – CPO and Lower Queen Street Works – CPO diaphragm wall construction and underpinning, piling, excavation, tunnel construction, backfilling and reinstatement CPO Works Construction of diaphragm walls using bentonite slurry and cement

6 months

Form a containment bund or similar around bentonite processing facility to contain any spillages escaping from site. Bentonite spillage to be collected for reuse or transfer to bentonite plant.

Collection of all cement and bentonite slurry washings/spillage during pouring is to be reused or disposed of off site.

Underpinning of CPO

4 months

Apply dust control measures set out in Air Quality DWP. Capture contaminated water and discharge into treatment plant or dispose of off-site.

Excavate and backfill beneath the CPO building

8- 10 months

Dewatering of excavation by sloping excavations to a low sump/sediment pit for coarse sediment capture.

Captured water will then be pumped to a settling tank, assisted with chemical treatment if required, at ground surface. Water to be quality checked prior to discharging into stormwater system.

Excavator loading directly to waiting trucks for immediate transfer of spoil off-site for disposal at an approved landfill.

Cleaning up of any spillage of ground materials. Water from the excavation is to be collected and pumped to settling tanks.

All concrete washings/spillage during pouring is to be collected at a low point in the excavation and disposed of off-site.

Construction of concrete tunnel base slabs and walls

6- 7 months

Collection of all contaminated washings/ spillage during pouring is to be collected and disposed of offsite.

CPO concrete floor reinstatement Reinstatement of CPO fixtures and fitting

Up to 15 months

Clean any concrete spillage immediately.

Capture contaminated water and discharge into treatment plant or dispose offsite as appropriate depending on nature of the contamination.

Erosion and Sediment Control Plan

June 2016

21 Construction Activity

Approx.

Duration

Specific ESC measure(s)

Lower Queen Street Works Remove Lower Queen Street concrete asphalt road surface and utilities

3 months

Install geotextile and filter socks under and around nearby stormwater catchpit grates.

Piling under Lower Queen Street using anger procedure

3- 4 months

Immediate transfer of spoil into trucks for off-site disposal.

Collection of soil contaminated water into settling tanks, assisted with chemical treatment if required, prior to stormwater network discharge.

Excavate below Lower Queen Street for tunnels

3 months

Form a barrier wall around the excavation to prevent clean water entering the work site and provide protection against flooding risk.

Construct canopy over at least 60% of the exposed excavation area to minimise the amount of rainfall within the excavation area. Runoff from canopy to be conveyed into street kerb and channel.

Dewatering of excavation by sloping excavations to a low sump/sediment pit for coarse sediment capture.

Captured water will then be pumped to a settling tank, assisted with chemical treatment if required, at ground surface. Water to be quality checked prior to discharging into stormwater system.

Excavator loading directly to waiting trucks for immediate transfer of spoil off-site for disposal at an approved landfill.

Cleaning any spillage of ground materials will be required especially when loading disposal trucks.

Contaminated water to be collected and transferred to settling tanks prior to discharge.

Construction of concrete tunnel base slabs and walls

6 months

Collection of all contaminated washings/ spillage during pouring to be collected and disposed off site.

Backfilling and reinstatement of Lower Queen Street

12 months

Apply dust control measures in accordance with the Air Quality DWP Leave all ESC measures in place until all Lower Queen Street works are complete.

All Stage 3 Works

Collection of groundwater during construction of tunnel walls

Up to 12 months

Collection of all water runoff at a low sump/sediment pit for coarse sediment capture. Captured water will then be pumped to a settling tank at ground surface.

Water to be quality checked prior to discharging into stormwater system.

Backfill to underside of structures

3 months

Apply dust control measures in accordance with the Air Quality DWP. Monitor conveyer belt spillage when transporting backfill into CPO building. All washings to be collected and transferred to onsite setting tank.

Leave all ESC measures in place until all CPO building works are complete.

Erosion and Sediment Control Plan

June 2016

22 Construction Activity

Approx.

Duration

Specific ESC measure(s)

Stage 4 – Reinstatement Backfilling and reinstatement Station Plaza and Streetscape in Project area

4.12

3 months

Apply dust control measures in accordance with the Air Quality DWP.

Certification of sediment control devices

Prior to construction (bulk earthworks) commencing, a certificate signed by a senior qualified person shall be submitted to AC (Team Leader Central Monitoring) to certify that the erosion and sediment controls relevant to the enabling works have been constructed in accordance with the certified ESCP. Certification details of diversion bunds and sumps will be supplied immediately upon completion of construction. Information supplied (if applicable) will include: a b

contributing catchment area; shape of structure (dimensions of structure);

c d

position of inlets/outlets; and stabilisation of the structure.

4.13

Modification to structural controls

In the event that any minor modifications to the structural controls system (treatment tanks) are required during the Project, the following information shall be provided to AC: a b

Plans and drawings outlining the details of the modifications; and Supporting information that details how the proposal does not affect the capacity or performance of stormwater management systems.

All information shall be submitted to, and the proposed modifications certified by AC (Team Leader Central Monitoring), prior to implementation.

Erosion and Sediment Control Plan

June 2016

23

5

Monitoring and Maintenance

As part of the erosion and sediment control measures, on-going monitoring will be undertaken for the full duration of the works. This will ensure that all of the control measures detailed in this ESCP have been properly implemented and are functioning effectively.

Monitoring and maintenance activities will include: a

Seven day weather forecast. Works will be programmed in accordance with weather predictions.

b

Monitoring the turbidity or clarity distance and pH values of the water exiting the settlement tank will be undertaken regularly with a checklist recorded and kept on site.

If assisted settlement is required using non-chemical or chemical coagulants/flocculants, monitoring of dosing rates will be included. The application of the coagulants/flocculants will be carried out in accordance with best practice principles and the CTMP in Appendix B. Sediment accumulation in the settlement tank. When the volume reaches 20% of the storage volume, the tank will be desilted by sucker truck.

c

d e

Daily monitoring of the containment measures at the high risk spillage areas and undertaking maintenance of these as required.

Daily monitoring and cleaning of the vehicle access ramps.

f g h

i

Regular monitoring of the surface silt control measures (silt fences, catchpit silt capture and bunding) for silt capture effectiveness and non-exacerbation of flooding during rainfall events.

Monitoring of excavated materials and groundwater quality for any evidence of contamination requiring special management measures (refer to the Contamination DWP for details).

Other on-site activities such as storage of chemicals, refuelling facilities and practices, site offices, temporary stockpiles, dust control, noise control, etc. will be monitored and maintained in accordance with the specified standards outline in the relevant DWPs and the CRL and BTC designation and resource consent conditions.

The monitoring activity items and frequency proposed are summarised in Table 5.1.

Table 5.1:

Summary of monitoring activity

Aspect

Frequency

Location

Monitoring details

Influent water quality entering the treatment plant

Details provided in the CTMP (provided at Appendix B)

Reporting Monthly compliance reports sent to AC consent officer

Effluent water quality exiting the settlement process Seven day weather forecast

Daily

From two or more reliable forecast sources

Record daily

Sediment accumulation in settlement tank

Monthly

In settlement tank

Use staff with round plate on bottom to rest on silt surface, or other effective means

Bentonite processing area

Daily

At processing area

Check for spillages, effective containment

Erosion and Sediment Control Plan

June 2016

24 Aspect

Frequency

Location

Monitoring details and need for off-site disposal of contaminated fluids

Concrete production areas

At production areas

Vehicle access ramps

At access ramps

Clean up spilled ground material during truck filling and wash surface of ramps if required

Surface silt control measures

Daily

At silt control measures

Clean, adjust and replace control measures as required

Check excavated materials and groundwater for any contamination

Daily initially during excavations, then less frequent if safe to do so

At points of excavation

Testing of soil and water samples

Clean water diversions (bunds), barriers (sediment) and overland flow paths

Weekly and before forecast rain events

In Lower Queen Street

Visual check that the bunds and barriers are intact and clean

Stockpiles

Daily

Within excavations and possibly Lower Queen Street

Visual check that dust control and sediment runoff prevention measures are effective

Drains and sumps / pumps

Daily

Within excavations

Visual check that drains and pumps are not blocked and are operating satisfactorily

Other site activities

Weekly

At respective site activities

Visual inspection

Erosion and Sediment Control Plan

Reporting

June 2016

25

6

Roles and Responsibilities

The key management roles in relation to environmental management during construction are outlined in the Project CEMP. Specific roles relating to this ESCP are detailed in Table 6.1.

Table 6.1:

Roles and responsibilities

Role

Responsibilities

Construction Manager

Inspection of works to assess compliance with the ESCP and sub-plans – including operation and maintenance of the Chemical Treatment System and daily monitoring.

Environmental and Sustainability Manager

On-site compliance with designation and resource consent conditions and other requirements, and tracking compliance information.

Report to AT changes to construction techniques or natural environmental changes which require alterations to approved ESCP or new resource consents.

Prepare, review and update the ESCP and CTMP. Facilitate and oversee environmental monitoring -– including daily Chemical Treatment System monitoring.

Erosion and Sediment Control Engineer

Ensure all erosion and sediment control measures are constructed and implemented in accordance with the ESCP and industry standards.

Hold ongoing weekly or fortnightly meetings with Site Supervisors and other necessary personal to review the effectiveness of the erosion and sediment control measures that have been implemented.

Site Supervisors

Hold preconstruction meeting prior to the commencement of work in each ACZ and advise all staff of erosion and sediment control measures to be put in place.

Attend ongoing weekly or fortnightly meetings to review the effectiveness of the erosion and sediment control measures that have been implemented.

All staff

Undergo erosion and sediment control training. Not relocate or alter erosion and sediment control devices without appropriate authority.

Erosion and Sediment Control Plan

June 2016

26

7

Environmental Training

7.1

Project staff

All Project staff (contractors and subcontractors) will undergo general environmental awareness training and training about their responsibilities relating to this ESCP. Training requirements are described in full detail within the CEMP. Specific training requirements relating to this ESCP are outlined in Table 7.1.

Table 7.1:

ESCP training requirements

Training requirements

Frequency

Attendance

Training on ESCP requirements and resource consent conditions. Record to be kept of all training material and attendees.

As required and during new staff induction

All new staff members

Tool box meetings on site to include erosion and sediment control as a standard agenda item. Record to be kept of all training material and attendees.

Weekly tool box meetings, or as required (e.g. start of new substantial activity)

Erosion and Sediment Control Engineer, Site supervisors, delegated staff member and duty managers

Construction, maintenance and inspections of erosion and sediment control devices

As required

Erosion and Sediment Control Engineer, Site supervisors, and delegated staff members

Responding to complaints regarding erosion and sediment control and water discharges.

As required and during new staff induction

Site manager, delegated staff member and duty managers

Erosion and Sediment Control Plan

June 2016

27

8

Complaints

Procedures for investigating and responding to complaints are set out in Section 12 of the Project Communication and Consultation Plan and Section 5.3 of the CEMP. It is important to ensure that any complaints are recorded and promptly investigated to identify and resolve the cause of the complaint. The requirements and procedures relating to complaints are detailed below. The requirements and procedures relating to consultation with neighbouring sensitive receivers is otherwise set out in the Communication and Consultation Plan.

8.1

Complaints response

The Project Hotline will be clearly included in any written Project notifications and on signage located in proximity to the Project area.

Any erosion and sediment control complaints received by the Project Hotline will be recorded in a complaints file, and investigation will be undertaken as outlined in the CEMP and the Project Communication and Consultation Plan. The investigation will involve the following: Information about the incident as described by the complaint.

Acknowledge receipt of the concern or complaint. An initial response shall be undertaken within 24 hours of receiving a complaint, and resolved as soon practicable.

Weather conditions at the time of the complaint.

Reporting the findings and recommendations.

Actions and time taken to close-out complaint.

Communication with the complainant.

Reporting of the investigation in the complaints file.

A record of all concerns and / or complaints received will include, where applicable: The name of the person(s) who raised the concern or complaint (unless they elect not to provide this) and details of the concern or complaint.

Weather conditions at the time of the concern or complaint, including wind direction.

Details of any observed discharge coming from the site by the person investigating the complaint.

Known construction activities at the time and in the vicinity of the complainant during the concern or complaint period.

Remedial actions undertaken (if any) and the outcome of these, including monitoring of the activity.

An investigation of the complaint will require the site supervisor or delegated staff member to go around the whole site and make visual observations about activities occurring on site. This may also include going to the location where the complainant observed the impact.

At all times during the complaints investigation, appropriate health and safety procedures must be followed.

Erosion and Sediment Control Plan

June 2016

28

9

ESCP Review

This ESCP has undergone a review process with the Community Liaison Group (CLG) established for the Project and a suitably qualified independent peer reviewer. An explanation of how any comments from the CLG and Peer Reviewer are addressed in this ESCP is provided in Appendix E.

9.1

ESCP Review

This ESCP will be reviewed throughout the course of the Project: a

To reflect material changes associated with changes to construction techniques, the natural environment or due to unresolved complaints; and

b

As part of the annual management review of the ESCP.

A management review of the ESCP will be undertaken by the Project Management Team and AT representatives. The management review will be organised by the Environmental and Sustainability Manager and the Project team will be informed of any changes to this ESCP through the regular Project communications processes. The review will take into consideration: Compliance with the resource consent conditions, the CEMP, DWPs and EMPS (including site specific plans) and material changes to these plans Any significant changes to construction activities or methods Key changes to roles and responsibilities within the Project team Changes in industry best practice standards Changes in legal or other requirements (social and environmental legal requirements, consent conditions, AT objectives and relevant policies, plans, standards, specifications and guidelines) Results of inspections, monitoring and reporting procedures associated with the management of adverse effects during construction Comments or recommendations from AC regarding the CEMP, DWPs and EMPs Unresolved complaints and any response to complaints and remedial action taken to address the complaint.

9.2

ESCP Updates

The process for updating this ESCP as a result of material changes to the Project or the annual review, is as follows (refer to CRL designation Condition 23 for further information): Any material change to this ESCP must be consistent with the purpose and objective of the relevant conditions listed in Table 1.1 of this document.

Affected parties and the CLG must be notified of the review and any material change proposed to this ESCP. This ESCP must clearly document the comments and inputs received from affected parties in relation to any material changes, along with a clear explanation of where any comments have not been incorporated, and the reasons why not.

Any material change proposed to this ESCP shall be subject to an independent peer review as required by CRL Condition 11.

Any material change proposed to this ESCP relating to an adverse effect shall be submitted for approval to Auckland Council Compliance and Monitoring Officer, at least 10 working days prior to the proposed changes taking effect. If any changes are not agreed, the relevant provisions of the RMA relating to approval of outline plans shall apply.

Erosion and Sediment Control Plan

June 2016

29 A copy of the original ESCP document and subsequent versions will be kept for the Project records, and marked as obsolete. Each new / updated version of the ESCP documentation will be issued with a version number and date to eliminate obsolete ESCP documentation being used.

A summary of the review process will be provided annually to AC and otherwise be made available on request.

Erosion and Sediment Control Plan

June 2016

Appendix A:

ISCA Requirements

Table A identifies the ISCA Credit Requirements relevant to this ESCP and the CTMP and where they are addressed in the document.

Table A: ISCA Requirements Credit

Requirement *

Relevant section

Comments

WAT-2 Level 1

Opportunities to reduce water use identified

Section 4.2

Project Sustainability Opportunities Register

WAT-3 Level 1

Identify non-potable sources that match demand

Section 4.2

Project Sustainability Opportunities Register

LAN-1 Level 3

>75% of the land used for the project is on previously disturbed land

Sections 2.1 and 2.2

LAN-2 Level 1

Conservation of topsoils, subsoils etc. has been considered

Section 4.9

Also refer to the Waste Avoidance and Resource Recovery Management Plan

LAN-2 Level 2

Subsoil and top soil is separated and protected from erosion etc.

Sections 4.2, 4.9

Also refer to the Waste Avoidance and Resource Recovery Management Plan

LAN-2 Level 2

95% of topsoil retains its productivity and is beneficially reused on or nearby to the project

LAN-3 Level 3

Assessment of contamination and remediation measures

Sections 3.1, 3.2, 5

Refer also to the Contamination DWP

LAN-4 Level 1

Run-off, flood risk and potential to increase flood risk have been included so there is no increase in flood risk

Sections 3.1, 3.2 4.2, 4.7

Refer also to the Industrial and Trade Activities Environmental Management Plan

DIS-1 Level 1

Baseline studies of existing receiving water environment have been carried out for the project

Sections 2.6, 3.1

Also refer to the Water Quality Assessment Report by Golder Associates, dated Dec 2014 and the Chemical Treatment Management Plan (Appendix B)

DIS-1 Level 1

Predictions for receiving water quality impacts have been developed for construction

Sections 2.7, 4.4 Appendix B: Chemical Treatment Management Plan Section 1.1, 2.1.1, 2.3

Also refer to the Water Quality Assessment Report by Golder Associates, dated Dec 2014 and the Chemical Treatment Management Plan (Appendix B)

DIS-1 Level 1

Measures to minimise adverse impacts to local receiving water quality

Sections 2.5.2, 2.5.3, 2.7, 3.1, 3.2, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 4.10, 4.11, 4.12, 5, 6

Also refer to the Chemical Treatment Management Plan (Appendix B) and Contaminated Soils DWP

Note – Topsoil is limited to garden/planted areas as the remainder has been developed.

Refer to the Waste Avoidance and Resource Recovery Management Plan

Credit

Requirement * identified and implemented

Relevant section Appendix B: Chemical Treatment Management Plan Section 1.1, 2.1, 3, 4, 6

DIS-1 Level 1

Monitoring of water discharges and receiving waters is undertaken at appropriate intervals and at times of discharge during construction

Section 3.2, 4.11, 5 Appendix B: Chemical Treatment Management Plan Section 3

DIS-1 Level 2

Modelling demonstrates no exceedances of water quality goals

Section 3.2 Appendix B: Chemical Treatment Management Plan Section 2.3

DIS-1 Level 2

All stormwater leaving the site is treated or filtered in accordance with appropriate urban stormwater guidelines unless it occurs during a 6 hour 1 in 5 year storm event

Section 3.2, 4.2, 4.4, 4.5, 4.8, 4.9, 4.10, 5 Appendix B: Chemical Treatment Management Plan Sections 2 and 3

* Refer to ISCA Rating Tool for full details of the requirement

Comments

Appendix B:

Chemical Treatment Management Plan

Auckland City Rail Link In association with:

ENABLING WORKS CONTRACT 1 CHEMICAL TREATMENT MANAGEMENT PLAN

Document ref: CRL-BTM-ENV-DOW-PLN-000344 Revision: 4 FINAL June 2016

COMMERCIAL IN CONFIDENCE CHEMICAL TREATMENT MANAGEMENT PLAN

June 2016

Version history Rev.

Date

Version details

Prepared by

Reviewed by

1

December 2015

Draft for Auckland Transport review

C Chryssafis

P Roan

2

January 2016

Draft for CLG review

C Chryssafis

R Jenkins

3

April 2016

Draft incorporating Auckland Council Comments

C Chryssafis

P Roan

4

June 2016

Final

C Chryssafis

P Roan, R Jenkins

Distribution Date

Version

Issued to

Quantity & type

Approved for the DSBJV by

21 December 2015

Draft

Auckland Transport

1x Electronic

D Burtenshaw

22 January 2016

Draft

Community Liaison Group

1x Electronic

D Burtenshaw

21 May 2016

Draft

Auckland Transport

1x Electronic

D Burtenshaw

2 June 2016

Final

Auckland Transport

1x Electronic 1 x Hard copy

D Burtenshaw

This document remains the property of DSBJV. Its contents are confidential and shall not be reproduced, destroyed or given away without express, written permission of DSBJV. The electronic version of this document in FULCRUM on designated serves(s) is the Master Copy and is a controlled document. Unless specifically noted, thereon, other copies of this document are uncontrolled. p:\30850\30850.0500 planning\30850.0512 (erosion and sediment)\workingmaterial\dwp\ctmp\crl-btm-env-dow-pln-000344 ctmp final 30 05 16.docx

CHEMICAL TREATMENT MANAGEMENT PLAN

June 2016

Table of contents 1

Introduction 1.1 Sediment laden water 1.2 Purpose of the Chemical Treatment Management Plan 1.3 Relevant Conditions 1.4 CTMP review and updates

1 1 2 2 5

2

Chemical treatment plant 2.1 Treatment system overview 2.1.1 Treatment design flow 2.1.2 Settlement unit 2.2 Assisted settlement 2.3 Water discharge quality 2.4 Modification to structural controls

6 6 6 7 7 7 8

3

Water Quality Monitoring 3.1 Monitoring 3.2 Daily record sheets 3.3 Weekly records 3.4 Monitoring reports 3.4.1 Initial monitoring report 3.4.2 Non-conforming result report 3.4.3 Regular monitoring reports

9 9 9 9 10 10 10 10

4

Storage and Handling of Chemicals

11

5 6

Emergency Spill Response Plan Responsibilities for Operation and Maintenance

12 13

Appendix A :

Flocculant testing

Appendix B :

Flocculant details

Appendix C :

Dosing system details

Appendix D :

Safety data sheets

Appendix E :

ISCA requirements

CHEMICAL TREATMENT MANAGEMENT PLAN

June 2016

Glossary of terms Term

Definition

ACZ

Active Construction Zone

AC

Auckland Council

ANZECC

Australian and New Zealand Environment Conservation Council

ARI

Annual Return Interval

AT

Auckland Transport

BTC

Britomart Transport Centre

CEMP

Construction Environmental Management Plan

CPO

Former Chief Post Office building

CRL

City Rail Link

CSA

Construction Support Area

CTMP

Chemical Treatment Management Plan

CTP

Chemical Treatment Plant

DSBJV

Downer Soletanche Bachy Joint Venture

ECBF

East Coast Bays Formation

ESCP

Erosion and Sediment Control Plan

ESRP

Emergency Spill Response Plan

ITA EMP

Industrial and Trade Activities Environmental Management Plan

PAC

Polyaluminium Chloride

TPH

Total Petroleum Hydrocarbons

TSS

Total Suspended Solids

CHEMICAL TREATMENT MANAGEMENT PLAN

June 2016

1

1

Introduction

The City Rail Link (CRL) project comprises the construction, operation and maintenance of a 3.4 km underground passenger railway, running between Britomart Station and the North Auckland Rail Line in the vicinity of Mt Eden station. The works relating to this Chemical Treatment Management Plan (CTMP) constitute part of the enabling works for the CRL. The works (the Project) involve the construction of an extension to the existing passenger rail network from the current termination point within the Britomart Transport Centre (BTC), westwards underneath the former Chief Post Office building (CPO) and Lower Queen Street. The Project footprint is shown generally by the blue shaded area in Error! Reference source not found. below.

Further details on the Project description, Active Construction Zones (ACZ), Construction Support Areas (CSA) and physical works are set out in Section 2 of the Erosion and Sediment Control Plan (ESCP).

LEGEND CRL alignment BTC designation CRL designation C1 worksite

Figure 1.1: Project Footprint

1.1

Sediment laden water

It is expected that sediment laden water will be generated during construction of the Project. Most of the water will be generated within ACZ D during Stage 3 of the work - cut and cover excavations in Lower Queen Street (refer Section 2.4 of the ESCP). The majority of Stages 1, 2 and 4 (works with ACZ A, B and C) will predominantly be undertaken under roof, with no rainfall contribution. Rainfall ingress from the works in Lower Queen Street (Stage 3) will also be reduced by the construction of a roof canopy over of the majority of the works (refer to Sections 2.2 and 2.5 of the ESCP for further details).

A settlement based treatment plant will be located on-site within CSA A, adjacent to the south east corner of the CPO building and next to the glasshouse. The treatment plant is a key component of the erosion and sediment control measures to be implemented for the Project as outlined in the ESCP. The treatment plant will remove sediment from contaminated water generated from the excavation works in order to achieve an acceptable water quality for discharge into the stormwater system. Assisted settlement (through use of a flocculant) may be required at times for the removal

CHEMICAL TREATMENT MANAGEMENT PLAN

June 2016

2 of small particles, such as fine silt and clay. The treatment plant will include capability to assist the settlement process with the use of flocculant when required.

The need for chemical treatment, along with the type of treatment, will be confirmed when soil samples from the Project area become available and bench testing of settlement and flocculants has been undertaken. The necessary soil samples will be collected during future site investigations and pile installation, approximately 5 months before commencement of the main excavations in the CPO and Lower Queen Street. The CTMP will be updated when more site specific information becomes available.

The treatment plant, including the chemical treatment facility, is hereafter referred to as the chemical treatment plant (CTP).

This CTMP has been prepared by Tonkin & Taylor Ltd (T+T) for the Downer Soletanche Bachy Joint Venture (the Contractor – DSBJV) and forms part of the Construction Environmental Management Plan (CEMP) for the Project.

1.2

Purpose of the Chemical Treatment Management Plan

This CTMP is required under Condition 50 of the CRL Britomart to Wyndham Street land use consent R/REG/2014/5430 and Conditions 99 to 104 of discharge permit R/REG/2014/5436.

This CTMP outlines: Specific design details of the chemical treatment system, including details of the optimum dosage; Water discharge quality; Monitoring, maintenance and contingency programme; Results of initial chemical treatment trial; Spill contingency plan; and Responsibilities for the long term operation and maintenance of the chemical treatment system.

1.3

Relevant Conditions

Table 1.1 outlines the resource consent conditions relevant to this CTMP and where they are addressed in the document.

Table 1.1: Condition No.

CTMP resource consent conditions Condition

Relevant section of the CTMP Land Use Consent R/REG/2014/5430

Chemical Treatment Management Plan (“CTMP”) 50

At least 20 working days prior to the commencement of construction, a CTMP which confirms the measures that will be taken to ensure that construction of the Project or Project Stage will be generally consistent with the Water Quality Assessment and the Industrial and Trade Activities Assessment prepared by Golder Associates (NZ) Limited, both dated December 2014 shall be submitted to Council (Team Leader Central Monitoring) for certification.

CHEMICAL TREATMENT MANAGEMENT PLAN

This document

June 2016

3 51

The Consent Holder shall request the Council’s (Team Leader Central Monitoring) determination as to whether the CTMP can be certified, in writing, within 10 working days of receipt of the CTMP.

52

The CTMP shall include, but not be limited to, the following matters: a. Specific design details of the chemical treatment system based on a batch dosing methodology for the site’s settlement tanks, including the potential for use of non-chemical flocculants (e.g. chitin based flocculants such as Haloklear); b. Monitoring, maintenance (including post-storm) and contingency programme (including a record sheet); c. Details of optimum dosage (including assumptions); d. Results of initial chemical treatment trial; e. A spill contingency plan; and f. Details of the person or bodies that will hold responsibility for the long term operation and maintenance of the chemical treatment system and the organisational structure which will support this system.

53

Any change to the CTMP shall be submitted to the Council (Team Leader Central Monitoring) for certification. No activity reliant upon a change to the CTMP can be undertaken until the change can be certified. The Consent Holder shall request that the Council’s (Team Leader Central Monitoring) determination as to whether the proposed change can be certified, in writing, within in 10 working days of submission of the change.

This document

2

3 an d 5 Appendix C Appendix A 5 6

1.4

Washwater and Wastewater Discharges – Discharge Permit R/REG/2014/5436 Structural Controls 99

100

The Consent Holder shall ensure that the following structural controls are constructed for the following catchment areas and design requirements and they are completed prior to discharges commencing from the site.

Works

Device catchment area

Design requirements

Settlement Tanks (2X 12,000l tanks), located in CSAs 2 and 4

All ACZs

Discharge levels as per monitoring Condition 101

21

Bunding of Environmentally Hazardous Substances

As required

110% of largest container

4

In the event that any minor modifications to the structural controls system are required, the following information shall be provided to Council: a. Plans and drawings outlining the details of the modifications; and b. Supporting information that details how the proposal does not affect the capacity or performance of stormwater management systems.

All information shall be submitted to, and the proposed modifications certified by the Council (Team Leader Central Monitoring), prior to implementation.

2.4

Settlement tanks are located in Construction Support Area A (adjacent to Galway Street) as opposed to Construction Support Area B / Construction Support Area 2 (Lower Queen Street) in order to create a more efficient CSA layout 11

CHEMICAL TREATMENT MANAGEMENT PLAN

June 2016

4 Discharge Monitoring 101

Within 30 days of the installation of the water treatment system, and prior to operation, a discharge monitoring programme, to assess the ongoing adequacy of all management practices, shall be developed and submitted to the Council (Team Leader Central Monitoring) for certification. The monitoring programme shall include, but not be limited to: a. sampling location for final discharge from the site(s); b. sampling locations on site (i.e. swale inlets, outlets etc); c. methods and procedures for discharge sampling on a quarterly basis; d. monitoring parameters for analysis, which shall include: Daily Turbidity (NTU) pH Weekly Total Suspended Solids mg/L Copper (total) mg/L Zinc (total) mg/L Lead (total) mg/L Total Petroleum Hydrocarbons mg/L e. Identified trigger levels for each of the above parameters. These trigger levels shall be developed with reference to the ANZECC Guidelines for water quality where applicable; and f. The methods and procedures for investigating and reporting stormwater discharge monitoring results to the Council (Team Leader Central Monitoring).

2 and 3

The discharge monitoring programme shall be implemented upon completion of works set out in Condition 99.

3

103

Within five working days of receipt of sample results showing contaminants exceeding the agreed trigger levels (Condition 101(e)): a. an investigation shall be undertaken to determine why exceedances were detected and to identify any additional source controls or treatment required; and b. the results of the investigation shall be reported to the Council (Team Leader Central Monitoring).

3.1

104

Within eight weeks following the start of the monitoring required by Conditions 101 and 102, a monitoring report shall be submitted to the Council (Team Leader Central Monitoring). The monitoring report shall include, but not be limited to, the following: a. a summary of the monitoring results to date; b. an interpretation of those results and suggestions for improvement to the site operations; c. a programme for ongoing monitoring including the reporting of results; and d. a programme for the ongoing maintenance of the discharge water management and treatment system.

3.1

102

3.1 3.1 3.1 3.1

3.1

3.4

Reporting

CHEMICAL TREATMENT MANAGEMENT PLAN

June 2016

5

1.4

CTMP review and updates

This CTMP is a live document that will be reviewed and updated once soil samples have been obtained and sedimentation tests have been undertaken. Appendices B to D of this CTMP will be populated after soil testing has been undertaken. Further updates, if needed, during the course of the Project to reflect material changes associated with construction techniques or the natural environment may also be undertaken. Any material changes to the CTMP will be certified by Auckland Council (AC) prior to any on-site activity reliant upon the change commencing.

CHEMICAL TREATMENT MANAGEMENT PLAN

June 2016

6

2

Chemical treatment plant

2.1

Treatment system overview

The CTP will be located in CSA A, adjacent to the south east corner of the CPO building and next to the glasshouse (refer to Section 2.3 of the ESCP for further detail on the Project CSAs). The CTP will comprise: Header/stilling tank to receive, homogenise and still the influent water; Influent water quality monitoring point; Automated chemical dosing system and mixing point to introduce dosing chemicals if chemically assisted settlement is required (to be confirmed when bench testing of settlement and flocculants has been undertaken); Provision to allow manual dosing in case of malfunction of the automated system or a need to interrupt the automated dosing; Proprietary lamella type settlement unit for the settlement, capture and disposal of sediment and resulting in a compliant effluent water quality; Effluent water quality monitoring point; Effluent water discharge into a storage tank to supply water reuse activity of the construction works. The tank will have an overflow for discharging surplus water into the public stormwater system; Isolating valve upstream of the reuse tank to enable closure of the flow to the reuse tank and stormwater system if the effluent water quality is not fully compliant; Temporary storage tank to receive the effluent water on closure of the valve and until the water quality problem has been resolved and the valve reopened. A pump will recycle the water back to the header tank/stilling tank while a sump pump in the excavations continues to operate; and If poor effluent water quality is experienced such that it should not be recycled, the effluent water will be piped to a connection point from which it can be discharged into water tankers for disposal off site.

To minimise the space occupied by the treatment system, the header/stilling tank and chemical dosing equipment will be installed on top of the temporary storage tank. An indicative layout of the treatment system is shown on Figure 2 in Appendix A of the ESCP.

2.1.1

Treatment design flow

The pumping system from the excavations will have capacity to pump a maximum of 250 m3/day (2.9 l/s) of groundwater inflow plus 110 m3/day (1.3 l/s) of inflow from a 24 hour, 1 in 100 year Annual Return Interval (ARI) rainfall event. The latter inflow will be pumped over an 8 hour period, which will increase the required flow rate to 3.9 l/s. Thus, the total pumping capacity required will be at least 6.8 l/s.

To cater for the above flows, a pumping capacity of 8.0 l/s will be provided by two pumps, each with a capacity of 4.0 l/s. One operating pump will be able to handle all the groundwater inflow plus the inflow from normal rainfall events. Both pumps operating will handle the increased inflow during high rainfall events.

2.1.1.1

Temporary storage tank

A half-length steel shipping container will be used for the temporary storage tank with approximate dimensions of 6.1 m x 2.5m x 2.5 m, with an effective storage volume of approximately 35 m 3.

CHEMICAL TREATMENT MANAGEMENT PLAN

June 2016

7 Assuming the predicted maximum groundwater inflow rate of 250 m3/day and no rainfall, the tank would provide a storage period of approximately 3.5 hours during which the treatment process can be reviewed and adjusted to achieve the required water quality.

If the groundwater inflow is significantly less than the predicted maximum (see below), the storage tank volume would provide a 24 hour storage period for the inflow plus rainfall ingress during a 1 in 12 month ARI rainfall event.

2.1.1.2

Lower design flow

The predicted maximum short term groundwater inflow of 250 m3/day given in Table 10 of the Pattle Delamore Partners report, Auckland City Rail Link – Groundwater Effects Assessment – Britomart to Wyndham, December 2014, is understood to be conservative. Significantly lower inflow rates are expected, however the value will be reviewed as further groundwater modelling and site investigations are undertaken to inform the Project Groundwater and Settlement Contingency Monitoring Plan.

A lower inflow rate could allow a reduction in the pumping capacity from the excavations. For example, if the inflow rate was of the order of only 10 m3/day, the pumping capacity could be halved to a total of 4.0 l/s. In this case, two pumps each with a capacity of 2.0 l/s, would be sufficient.

The size of the settlement unit will not be reduced even if lower design flows are encountered. At a lower flow rate with the same unit size, particles of smaller size can be settled without chemical dosing (refer to Section 2.1.2 below).

2.1.2

Settlement unit

A Siltbuster HB 50 lamella type settlement unit will be used to provide the required settlement levels. The unit will be able to handle flow rates of up to 50 m3/hr (14 l/s). At an inflow rate of 4.0 l/s or 8.0 l/s, particle sizes down to less than 1 micron are expected to be captured without chemical dosing. Assisted settlement using chemical dosing, if required, will enable smaller particle sizes to settle out.

At a lower design flow rate of 4.0 l/s, particles less than 0.5 micron could be settled in the HB 50 unit, which could further reduce the need for chemical dosing.

2.2

Assisted settlement

Assisted settlement via coagulation and flocculation of the water from the excavations may be required if simple sedimentation does not provide the required discharge quality. Commonly used chemicals for this process include polyaluminium chloride (PAC) or a chitin based flocculant, which can assist with both processes.

Sedimentation tests will be conducted on soil samples retrieved from test boreholes as soon as the soil samples become available during further site investigations. Bench sedimentation tests using non-chemical flocculants (such as Haloklear) and chemical flocculants (such as PAC) will be undertaken on soil samples taken from the Project area when material becomes available from site investigations and pile construction. As mentioned in Sections 1.1 and 1.4 of this CTMP, Appendices B to D of this CTMP will be populated after the testing has been undertaken.

2.3

Water discharge quality

The discharge water quality to be attained was established in the Water Quality Assessment prepared by Golder Associates (NZ) Limited, dated December 2014 and is:

CHEMICAL TREATMENT MANAGEMENT PLAN

June 2016

8 A minimum water clarity for all discharges of 10 cm or greater measured with a black disc and Total Suspended Solids (TSS) less than 50 g/m3 for 95% of the time; pH between 5 and 9; and No visible total petroleum hydrocarbons (TPH) - sheen or odour.

Non-chemical flocculants will be used unless the required water quality cannot be achieved.

2.4

Modification to structural controls

In the event that any minor modifications to the structural controls system are required, the following information shall be provided to AC: a b

Plans and drawings outlining the details of the modifications; and Supporting information that details how the proposal does not affect the capacity or performance of stormwater management systems.

All information shall be submitted to, and the proposed modifications certified by AC (Team Leader Central Monitoring), prior to implementation.

CHEMICAL TREATMENT MANAGEMENT PLAN

June 2016

9

3

Water Quality Monitoring

3.1

Monitoring

The purpose of the water quality monitoring is to confirm the water being discharged meets the required discharge quality targets.

Effluent water quality monitoring will include testing for key contaminants (Copper, Zinc and Lead) cited in the Australian and New Zealand Environment Conservation Council (ANZECC) Guidelines for Fresh and Marine Water Quality (2000) for the protection of 95 percent of marine water species (refer to Table 3.1 below).

Table 3.1:

ANZECC (2000) Trigger Values for copper, lead and zinc

Chemical

95% Trigger Value for Marine Water (ug/L)

50 times 95% Trigger Value for Marine Water (ug/L)

Copper

1.3

65

Zinc

15

750

Lead

4.4

220

The test results for these contaminants will determine whether the effluent water will be discharged into the stormwater system after treatment or tankered off-site.

Water quality visual checks and water clarity tests will be conducted at the inlet and outlet points of the settlement unit. TSS and pH will be recorded using an automated instrument system, which will sample the effluent water prior to entry into the reuse storage tank. Testing for other contaminants will be done by drawing samples manually from the same location.

3.2

Daily record sheets

Daily record sheets will be completed by site staff to record the following information: Visual check of influent and effluent water clarity, pH, presence/absence visible TPH (e.g. conspicuous oil or grease film, sheen or odour), flocculant type and volume used, dosing system operation; Carry out a water clarity test of effluent: 10cm or greater measured with a black disk; Check pH results from datalogger to confirm pH is between 5 and 9; Record any notes for maintenance or additional information (e.g. ordering additional flocculant supplies); and Record of daily volume of chemicals used.

3.3

Weekly records

In addition, weekly samples of effluent will be taken and sent to an accredited laboratory and tested for: TSS mg/L; Copper mg/L; Zinc mg/L; Lead mg/L; and TPH mg/L.

CHEMICAL TREATMENT MANAGEMENT PLAN

June 2016

10

3.4

Monitoring reports

The monitoring reports outlined in Sections 3.4.1-3.4.3 below will be prepared and forwarded to AC (Team Leader Central Monitoring).

3.4.1

Initial monitoring report

Within eight weeks of monitoring commencing an initial report outlining: A summary of the monitoring results to date; An interpretation of those results and suggestions for improvement to the site operations were required; A programme for ongoing monitoring including the reporting of results; and Water treatment plant maintenance programme.

3.4.2

Non-conforming result report

Within five working days of receipt of sample results showing contaminants exceeding the trigger levels set out in Section 3 of the CTMP, an investigation will be undertaken to determine why exceedances were detected and to identify any additional source controls or treatment required.

The results of this investigation will be sent in a report format to AC (Team Leader Central Monitoring).

3.4.3

Regular monitoring reports

The frequency and content of the regular monitoring reports will be determined in the initial monitoring report.

CHEMICAL TREATMENT MANAGEMENT PLAN

June 2016

11

4

Storage and Handling of Chemicals

The water treatment chemicals (if assisted settlement is required) will be stored in CSA A in the vicinity of the treatment plant. The chemicals will be stored within bunded enclosures in order to contain any spillage or failure of container vessels or pipe connections.

The storage and monitoring of the chemicals will be undertaken by trained personnel in accordance with the requirements of the Project Industrial and Trade Activity Environmental Management Plan (ITA EMP). These personnel will be the same as those responsible for managing the chemical dosing of the influent water.

Monitoring will ensure all chemicals used on site are accounted for, and the daily volumes used will be captured on the daily record sheets.

CHEMICAL TREATMENT MANAGEMENT PLAN

June 2016

12

5

Emergency Spill Response Plan

Should chemical treatment be required during the Project, the chemical substances to be used will be in liquid form. A Project Emergency Spill Response Plan (ESRP) has been developed to set out the project spill management procedures. The ESRP is included in the Project CEMP as Appendix C to the ITA EMP.

CHEMICAL TREATMENT MANAGEMENT PLAN

June 2016

13

6

Responsibilities for Operation and Maintenance

The Construction Manager and the Environmental and Sustainability Manager will be responsible for the implementation of the CTMP, including the operation and maintenance of the treatment system, as outlined in Table 6.1.

Table 6.1:

Responsibilities for implementation of CTMP

Party

Responsibility

Construction Manager

Implements environmental protection measures in accordance with the contract, CEMP and sub-plans including CTMP. Inspection of works to assess compliance with the CTMP and sub-plans – including operation and maintenance of the Chemical Treatment System and daily monitoring.

Environmental and Sustainability Manager

Develops, implements and reviews environmental management systems including the CTMP On-site compliance with designation and resource consent conditions and other requirements, and tracking compliance information.

Undertakes regular site inspections and audits to ensure compliance with the CEMP and sub-plans, including the CTMP and consent conditions Manages maintenance and monitoring of the effectiveness of the Chemical Treatment System.

CHEMICAL TREATMENT MANAGEMENT PLAN

June 2016

Appendix A:

Flocculant testing

[To be completed after bench testing]

Appendix B:

Flocculant details

[To be completed after bench testing]

Appendix C:

Dosing system details

[To be completed after bench testing]

Appendix D:

Safety data sheets

[To be completed after bench testing]

Appendix E:

ISCA requirements

Appendix C:

Staging Plans

N

QUAY ST

STAGE 1 CONSTRUCTION ACTIVITIES JULY 2016 TO JANUARY 2017

100

CONSTRUCT TEMPORARY FACILITIES (INCLUDING NEW STAIRS) REMOVE EXISTING STAIRS AND ESCALATORS REMOVE/RELOCATE PUBLIC ARTWORK ROAD AND FOOTPATH ALIGNMENTS MODIFIED

80

90

EMERGENCY EGRESS MAINTAINED WHILE UPPER CPO IS TENANTED

70

TRAFFIC DIRECTION REVERSED ON TYLER ST

SITE ACCESS

SITE EGRESS REMOVE CANOPIES

50

60

QUEEN ELIZABETH II SQUARE

40

LAYDOWN AREA

PRECINCT

SITE EGRESS

10

20

30

(NOT PART OF WORKS)

ORIGINAL SCALE OF MM.

0

CONSTRUCTION ZONE WORK PHASED TO ALLOW EMERGENCY ONLY PUBLIC ACCESS DURING OPERATING HOURS SITE ACCESS

CPO TO REMAIN OPEN. UPPER FLOORS REMAIN TENANTED LAYDOWN AREA

SITE EGRESS

SITE ACCESS COMMERCE ST

QUEEN ST

GALWAY ST

REMOVE CANOPIES

REV

AMENDMENT

BY NAME

DATE

CITY RAIL LINK ENABLING WORKS CONTRACT 1 STAGE 1 OVERVIEW TEMPORARY STATION ENABLING WORKS

CONTRACT No.

880201-250

DWG. SCALE (A3 Original)

1:500 @ A3 DRAWING No.

REVISION

STAGE 1 CONSTRUCTION

09.05.2016

N

QUAY ST

STAGE 2 CONSTRUCTION ACTIVITIES JANUARY 2017 TO MAY 2017

100

CONSTRUCT DUST/NOISE BARRIERS STRIP OUT CPO CPO GROUND FLOOR DEMOLITION CPO DIAPHRAGM WALL CONSTRUCTION (BEGIN) B2 TEMPORARY ACCOMMODATION WORKS

80

90

MAIN CONSTRUCTION ACCESS INTO CPO. BUS SHELTERS REMOVED. SITE FENCED AND GLASSHOUSE PROTECTED. SITE PARKING PROVIDED ALONG TYLER ST

70

TRAFFIC DIRECTION REVERSED ON TYLER ST

TYLER ST

PRECINCT

CONSTRUCTION ZONE ALL PUBLIC ACCESS TO CPO CLOSED. UPPER FLOORS VACATED BY TENANTS AND USED AS SITE OFFICES AND STORAGE UNDERTAKE CPO WORKS AND COMMENCE DIAPHRAGM WALL INSTALLATION

WORK AREA SECURELY FENCED

ORIGINAL SCALE OF MM.

0

10

20

30

(NOT PART OF WORKS)

DRYWALL BENTONITE TREATMENT AREA

PUBLIC ACCES NEW STATION LAYOUT IN OPERATION

NOISE/DUST BARRIER BETWEEN CONSTRUCTION AND PUBLIC AREAS

PUBLIC ACCESS

GALWAY ST COMMERCE ST

40

50

60

QUEEN ELIZABETH II SQUARE

QUEEN ST

GALWAY AND COMMERCE STREETS UNAFFECTED

REV

AMENDMENT

BY NAME

DATE

CITY RAIL LINK ENABLING WORKS CONTRACT 1 STAGE 2 OVERVIEW CPO DEMOLITION AND PILING WORKS

CONTRACT No.

880201-250

DWG. SCALE (A3 Original)

1:500 @ A3 DRAWING No.

REVISION

STAGE 2 CONSTRUCTION

09.05.2016

N

QUAY ST

STAGE 3 CONSTRUCTION ACTIVITIES MAY 2017 TO MAR 2020 B2 ACCOMMODATION WORKS & B1-B2 ESCALATOR COMPLETE QUEEN ST PILING CPO AND QUEEN ST EXCAVATION UNDERPINNING CPO BREAK-THROUGH INTO PRECINCT WORKS TUNNEL CONSTRUCTION BACKFILL QUEEN ST REINSTATEMENT STATION BOH B2 WORKS CPO REBUILD

100

SITE BOUNDARY EXTENDED TO QUAY ST

80

90

AUXILIARY SITE ACCESS

70

TRAFFIC DIRECTION REVERSED ON TYLER ST

TYLER ST

40

50

60

QUEEN ELIZABETH II SQUARE

PRECINCT

CONSTRUCTION ZONE PUBLIC ACCESS TO CPO REMAINS CLOSED. UPPER FLOORS USED AS SITE OFFICES AND STORAGE COMPLETE UNDERPINNING, EXCAVATION AND CONCRETE WORKS READY TO CPO OPEN

ORIGINAL SCALE OF MM.

0

10

20

30

(NOT PART OF WORKS)

PEDESTRIAN ACCESS MAINTAINED VIA TEMPORARY FOOTBRIDGE OVER EXCAVATION

QUEEN ST CLOSED TO VEHICLES BETWEEN TYLER AND GALWAY. PEDESTRIAN ACCESS MAINTAINED

PUBLIC ACCES

CONSTRUCTION ZONE (BACK OF HOUSE AREA)

NEW STATION LAYOUT IN OPERATION

PUBLIC ACCES

DEMOLISH OFFICES AND CUT THROUGH SECANT PILE WALL

GALWAY ST

REV

AMENDMENT

GALWAY AND COMMERCE STREETS UNAFFECTED

QUEEN ST

SITE BOUNDARY AT QUEEN ST / CUSTOM ST INTERSECTION (EXTENDED TO CUSTOM ST)

COMMERCE ST

SITE ACCESS

BY NAME

DATE

CITY RAIL LINK ENABLING WORKS CONTRACT 1 STAGE 3 OVERVIEW PILING, EXCAVATION, CONCRETE WORK AND BACKFILL

CONTRACT No.

880201-250

DWG. SCALE (A3 Original)

1:500 @ A3 DRAWING No.

REVISION

STAGE 3 CONSTRUCTION

09.05.2016

N

QUAY ST

STAGE 4 CONSTRUCTION ACTIVITIES APR 2020 TO JUN 2020

70

80

90

100

CPO OPEN REINSTATEMENT OF QUEEN, TYLER & GALWAY & STATION PLAZA TIE IN RAIL TUNNELS TO EXISTING RAIL AT STATION LINE REMOVE TEMPORARY ACCOMMODATION

NEW PUBLIC REALM REINSTATEMENT

60

QUEEN ELIZABETH II SQUARE

TRAFFIC DIRECTION REVERSED ON TYLER ST

TYLER ST

40

50

REMOVE TEMPORARY ACCOMMODATION BUILDING

PRECINCT

10

20

30

(NOT PART OF WORKS)

0

CPO OPEN ORIGINAL SCALE OF MM.

PUBLIC ACCESS CONSTRUCTION ZONE TIE INTO EXISTING RAIL ALIGNMENT AT STATION LEVEL

QUEEN ST REOPENED

GALWAY AND COMMERCE STREETS UNAFFECTED

QUEEN ST

REV

AMENDMENT

COMMERCE ST

GALWAY ST

BY NAME

DATE

CITY RAIL LINK ENABLING WORKS CONTRACT 1 STAGE 4 OVERVIEW UNDERPINNING REMOVAL AND CPO FIT-OUT

CONTRACT No.

880201-250

DWG. SCALE (A3 Original)

1:500 @ A3 DRAWING No.

STAGE 4 CONSTRUCTION

REVISION

09.05.2016

Appendix D:

Drawings

Figure 1

Catchment Boundaries

Figure 2

ESCP Treatment Plant Layout Plan

Figure 3

ESCP Treatment Plant Sections

ACZ-D CSA-B

CSA-C

Extent of works

\\albtpfile\data\rep\Auckland\live\tt\CAD\30850\30850.0512\CAD\FIG\30850.0512-F1.dwg, F01, 18/12/2015 12:11:25 p.m., mra

ACZ-C ACZ-B CSA-A

Legend ACZ CSA

Active Construction Zone Construction Support Area Open Trench Piled Walls Clean Water Runoff Barrier Clean Water Runoff Direction

Aerial photo sourced from Auckland Council GIS Website

Note:Clean water runoff diverted around excavation by way of footpath or pedestrian footbridge

105 Carlton Gore Road, Newmarket, Auckland www.tonkintaylor.co.nz

L:\30850\30850.0512\CAD\FIG\30850.0512-F2.dwg, F02, 17/12/2015 12:28:23 p.m., kah

105 Carlton Gore Road, Newmarket, Auckland www.tonkintaylor.co.nz

L:\30850\30850.0512\CAD\FIG\30850.0512-F3.dwg, F03, 17/12/2015 12:29:47 p.m., kah

105 Carlton Gore Road, Newmarket, Auckland www.tonkintaylor.co.nz

Appendix E:

CLG comments

Community Liaison Group Comments Comments received from the CLG are as follows: Date

CLG Member

Comment

Response

19 January 2016

Tim Coffey

Will the flood barrier around the Lower Queen Street excavation impede pedestrian access?

No, the barrier will be inside the construction area. Pedestrian access along Lower Queen Street will be maintained at all times during the construction works, however during works in Lower Queen Street (Stage 3), access will be directed to the western side of the street.

Section 4.2 of the ESCP updated to clarify location of bund.

4 May 2016

Coopers and Company

Section 9, ESCP Review, sets out the formal review process and mentions taking into account comments or recommendations of Council but doesn’t mention the CLG. Condition 19 states that the consent holder is required to consult with the CLG upon the review of this plan. Reference should be included here of this obligation.

Section 9 text has been updated to reference Condition 19 requirement to consult with the CLG upon the review of the ESCP.

4 May 2016

Coopers and Company

It should be noted that Appendix B - Chemical Treatment Management Plan is in response to Condition 50.

Section 1.1 text updated to specifically reference Conditions 48 (f) and 50 -53 which sets out the requirement for Chemical Treatment Management Plan.

Appendix B, Section 12 states that the CTMP is required under Condition 50 of the CRL Britomart to Wyndham Street land use consent R/REG/2014/5430 and Conditions 99 to 104 of discharge permit R/REG/2014/5436.

4 May 2016

Coopers and Company

Appendix C – Staging Plans are dated 14/11/14 and refer to the possibility of the upper floors of the CPO remaining tenanted in stage 1 (May to October 2016) and vacated for Stage 2 (October to June 2017). Need to ensure these dates marry with dates advised through Public Works Act process. Our understanding is that they currently do but have not yet seen final Public Works Act proposal.

Also the plans refer to the upper levels of the CPO as

The Staging Plans dates are not supposed to correspond with the tenancy of the upper floors of the CPO building. Dates and plans detailing the tenancy of the CPO upper floors as site office and for storage will be agreed with Cooper and Company through the Public Works Act process.

th

No amendments made to this ESCP.

being used as a site office and for storage. Cooper and Company would like details of what areas are proposed to be used for - given their interest in receiving the upper floors of the CPO back in the same high quality fit-out as they were at the time AT takes possession.

4 May 2016

Coopers and Company

Appendix D -CLG comments, no comments are included.

Does this mean none were received?

One CLG comment was received and is referenced above in this table.

13 May 2016

Coopers and Company

Section 4.9 has a typo ““will not be exceed”

Section 4.9 text updated to correct typo.