Karangahape Station Early Works Air Quality Delivery Work Plan
CRL-KRD-RME-LKA-PLN-800009
Revision: Final Date: October 2019
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Air Quality Delivery Work Plan
Table of contents 1. Introduction ............................................................................................... 5 1.1
Karangahape Station ......................................................................................................... 5
1.2
Air Quality DWP Staging .................................................................................................... 6
1.3
Purpose of the Air Quality DWP ........................................................................................ 6
1.4
Relevant Conditions .......................................................................................................... 6
1.5
Sustainability..................................................................................................................... 9
1.6
DWP Review and updates ............................................................................................... 10
1.7
AQ DWP Author .............................................................................................................. 10
2. Karangahape Early Works .........................................................................11 2.1
Overview of Works .......................................................................................................... 11
2.2
Discharges to Air ............................................................................................................. 11
2.3
Sensitive Locations .......................................................................................................... 12
2.4
Key Personnel.................................................................................................................. 12
3. Environmental Standards ..........................................................................13 3.1
Environmental Performance Standards........................................................................... 13
4. Monitoring Requirements .........................................................................14 4.1
Dust Monitoring .............................................................................................................. 14
4.2
Visual Inspection and Monitoring Methods .................................................................... 14
4.3
Instrumental Monitoring ................................................................................................. 14
4.3.1.
Dust ............................................................................................................................ 14
4.3.2.
Meteorological Monitoring.......................................................................................... 15
4.3.3.
Dust Trigger Alerts....................................................................................................... 15
4.4
Monitor Locations ........................................................................................................... 15
4.5
Monitoring Data .............................................................................................................. 16
4.6
Monitoring Equipment Maintenance .............................................................................. 16
4.7
Monitoring for Hazardous Air Pollutants......................................................................... 16
4.8
Odour Monitoring ........................................................................................................... 16
5. Operating Procedures ...............................................................................18 5.1
General Methods of Dust Control.................................................................................... 18
5.2
Dusk Risk Index ............................................................................................................... 18
5.3
Dust Mitigation Measures ............................................................................................... 19
5.3.1. Page 3
Methods of Dust Control – All Areas (Low Risk) ........................................................... 19
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Air Quality Delivery Work Plan 5.3.2.
Further Methods of Dust Control – Moderate Risk ...................................................... 20
5.3.3.
Further Methods of Dust Control – High and Extreme Risk Conditions ......................... 20
5.3.4.
Equipment Malfunction ............................................................................................... 21
5.4
Review of Dust Mitigation ............................................................................................... 21
5.4.1.
Sources of Information ................................................................................................ 21
5.5
Dust Control during Contaminated Material Handling .................................................... 22
5.6
Odour Mitigation Measures ............................................................................................ 22
5.7
Control of Vehicle Exhaust Emissions .............................................................................. 22
5.8
Dust contingency measures............................................................................................. 23
6. Communication with Affected Parties ......................................................24 6.1
Complaints ...................................................................................................................... 24
7. Environmental Training .............................................................................25 7.1
Project Staff..................................................................................................................... 25
8. Record Keeping .........................................................................................26 8.1
Air Quality Diary .............................................................................................................. 26
Appendix A: Record of CLG, IPR and Auckland Council Comments .................27 A1. CLG Comments ..........................................................................................27 A2. IPR Comments ...........................................................................................27 A3. Auckland Council Comments.....................................................................27 Appendix B: ISCA Requirements......................................................................29 Appendix C: Beaufort Scale .............................................................................30 Appendix D: Dust Risk Index ...........................................................................31
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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 CRL also involves the construction of two new underground stations at Aotea and Karangahape and the redeveloped Mt Eden Station (refer to Figure 1-1). The design and construction of the CRL infrastructure between the Aotea and Mt Eden Stations is being delivered by the Link Alliance.
Figure 1-1: CRL Route and Location
This Air Quality Delivery Work Plan (AQ DWP) has been prepared in relation to construction of the new Karangahape Station.
1.1 Karangahape Station The Karangahape Station will consist of two entrances, one at Beresford Square / Pitt Street and the other at Mercury Lane, linked together by platforms with two mined tunnels approximately 32m below Pitt Street. The Station will also comprise equipment rooms, ventilation systems and emergency egress at both Mercury Lane and Beresford Square / Pitt Street. Given the nature and scale of the Karangahape Station construction, works will be undertaken in a staged manner, involving: · · ·
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Early works (demolition, network utility relocation and site establishment works) – to be undertaken from October 2019 through to early 2020; Main construction works (construction of the station and mined tunnels for the rail tracks) – to be undertaken from early 2020 through to late 2023; and Public realm reinstatement – likely to be undertaken from late 2022 to late 2024.
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1.2 Air Quality DWP Staging To reflect the staged construction approach for the Karangahape Station, this AQ DWP will be developed in stages. This AQ DWP addresses the Karangahape Station early works, which are described in detail in the Construction Environmental Management Plan (CEMP) and summarised in Section 2 of this AQ DWP. AQ DWPs will also be prepared for the main construction works and the public realm reinstatement.
1.3 Purpose of the Air Quality DWP This AQ DWP has been prepared to identify the measures that will be implemented to mitigate and manage the potential adverse effects on air quality during the Karangahape Station early works. The objective of the AQ DWP is to detail the best practicable options to avoid, remedy, or mitigate the adverse effects of discharges of dust, odour and hazardous air pollutants generated by construction activities for the works. Amongst other things, this AQ DWP includes procedures for ensuring that construction and earthworks activities do not result in the following effects beyond the boundary of the work site: ¡ ¡
Offensive or objectionable dust or odours; or Hazardous air pollutants that cause, or are likely to cause, adverse effects on human health, environment or property.
The CRL designation 2500-4 (Condition 59) requires the preparation of an AQ DWP, while condition 222 of discharge permit R/REG/2016/1899 require the preparation of an Air Quality Management Plan (AQMP). These two separate requirements have been combined and are addressed in this single AQ DWP. This AQ DWP has been developed to enable consultation with and feedback from the Karangahape Community and Business Liaison Group (CLG); and review by the Independent Peer Reviewer (IPR) prior to submission to Auckland Council (as per designation Conditions 7 and 11, and resource consent Condition 19). A record of consultation outcomes is included in Appendix A. This AQ DWP forms part of the CEMP for the Karangahape Station early works.
1.4
Relevant Conditions
Table 1-1 identifies the designation and resource consent conditions relevant to this AQ DWP and where they are addressed in the document. Table 1-1: Air Quality conditions and location in AQ DWP
Condition No.
Condition
Relevant section of DWP
CRL Designation Conditions 59.1
An Air Quality DWP shall be prepared to avoid, remedy or mitigate the adverse effects on air quality during the construction of the City Rail Link or any part of it.
Whole Document
The objective of the Air Quality DWP is to detail the best practicable option to avoid dust and odour nuisance being caused by construction works and to remedy any such effects should they occur.
1.3
59.2 Page 6
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Condition No.
Condition
Relevant section of DWP
To achieve the above objective the following shall be included in the Air Quality DWP and implemented as required:
59.3
(a) The procedures to be implemented for the continuous monitoring of Total Suspended Particulate (TSP) concentrations and meteorology including, but not limited to, the establishment of two monitoring sites (to the north and south of the site);
4.3
(b) Identification of the sensitive locations, and the specific methods for monitoring, including trigger limits to determine whether further action (such as implementation of the mitigation measures discussed below or other mitigation measures) is required;
2.3, 5
(c) Procedures for responding to malfunctions with construction machinery or works causing accidental dust discharges including, but not limited to, the requirement to remedy any malfunction within 24 hours;
5.3.4
(d) Procedures for monitoring weather conditions and the requirement that water spray is used on soil stockpiles, any non-paved construction areas, and the wheels of trucks where dust may disperse beyond the site;
4.3
(e) Procedures for establishing when the covering of trucks will be required;
5
(f) Procedures for determining when hard surfaced areas in construction yards and active construction areas should be cleaned including, but not limited to, the requirement that such areas be cleaned whenever dust generation occurs due to traffic on these surfaces;
5
(g) Procedures for responding to discharges of odour (including in the event of excavation of contaminated sites) including, but not limited to, the requirement to address discharge of objectionable odour by immediately ceasing the activity causing the discharge;
4.7 ,5.6
(h) Procedures for equipment inspection (including timeframes for regular inspections), maintenance, monitoring and recording, including baghouses, pressure relief valves and high level alarms to mitigate dust emissions;
5
(i) Procedures for, where practicable, limiting dust and odour nuisance and the methods for monitoring these procedures including Identification of contingency measures to address identified and verified adverse effects on sensitive receptors.
5
Contingency measures may include options such as: (i) Cleaning of air filtration intakes; or
5.8
(ii) Cleaning of other buildings and infrastructure; and
5.8
(j) Procedures for responding to any complaints received and the timeframes for response to complaints and reporting;
5.8
(k) Cross references to the specific sections in the Communication and Consultation Plan which detail how the communities in the vicinity of construction works are to be communicated with on the management of the adverse effects relating to air quality.
6
Discharge Permit R/REG/2016/1899 Conditions 217
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This resource consent shall expire 15 years after the consent commences unless it has been surrendered or been cancelled at an earlier date pursuant to the RMA.
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Noted
Air Quality Delivery Work Plan
Condition No.
Condition
Relevant section of DWP
218
The Consent Holder shall ensure that all processes on the Project work site shall be implemented, operated, maintained, supervised, monitored and controlled so that any emissions authorised by this consent are maintained at the minimum practicable level.
This Document
219
Unless provided for by Condition 220, there shall be no dust or odour beyond the boundary of the Project work site caused as a result of on-site processes which, in the opinion of Council, is noxious, offensive or objectionable.
This Document
220
Any noxious, offensive or objectionable dust or odour beyond the boundary of the Project work site caused as a result of construction and earthworks activities associated with the Project shall be mitigated as soon as practicable in accordance with the requirements of the certified Air Quality Management Plan as required by Condition 222.
This Document
221
The Consent Holder shall ensure that beyond the boundary of the Project worksite, there shall be no hazardous air pollutant caused as a result of construction and earthworks activities associated with the Project that causes, or is likely to cause, adverse effects on human health, environment or property.
This Document
222
The Consent Holder shall review the draft Air Quality Management Plan – Aotea Station to North Auckland Line dated May 2016, and submit to Council (Team Leader Central Monitoring) a final AQMP/s which is generally consistent with the draft AQMP provided in support of the application.
This Document
223
The final AQMP/s shall be prepared by a Senior Qualified Person, provided to the Council (Team Leader Central Monitoring) for certification at least 20 working days prior to the commencement of construction and shall include: a. a clear identification of the type and location of the controls proposed; b. a detailed framework for the management, mitigation and monitoring of construction and earthworks activities associated with the Project; c. a focus principally on the sources of dust discharges, and d. an assessment of the risk of discharges from each ACZ and the associated CSA.
224
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The final AQMP/s shall also provide detailed methods including, but not limited to, the following matters: a. methods to ensure exposed surfaces remain dampened to minimise dust emissions (possible examples include a water spray system or other suitable system, water carts and other suppression methods); b. ensuring a 20 km/hr vehicle speed limit within the ACZs and CSAs; c. operation of wheel washes; d. regular sweeping of public roads around the exit points of ACZs and CSAs and sealed vehicle accessways within these areas; e. measures for supressing dust from any temporary stock piles (demonstrating how they are to be limited to no more than 24 mÂł of uncovered spoil at any one time in each ACZ); f. measures for the handling of cement associated with the forming of cement stabilised columns, including filter systems and high level alarms where a silo is used;
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This Document
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5.3.1 5.3.1 5.3.1 5.3.1 Not applicable
Air Quality Delivery Work Plan
Condition No.
225
Condition
Relevant section of DWP
g. covering of loads of material being delivered and removed from the site; h. instrument monitoring of dust concentrations (including identification of a monitoring methodology, monitoring network and appropriate alert thresholds) to ensure that any significant dust effects arising from the ACZs or CSAs are identified and remedied as soon as practicable throughout the Project; i. the locations of instrument dust monitoring sites, including at least three relocatable and/or fixed monitors to be associated with each of ACZs A, K and M, and the duration of this monitoring; j. measures for responding to continuous instrument dust monitoring trigger alarms, including contingency measures to reduce measured concentrations below the trigger thresholds and provisions for responding after standard operating hours; k. measures for undertaking meteorological observations and visual inspections of dust or other air discharges from the Project, to be completed at least on a daily basis, with all relevant information logged; and l. information regarding complaint logging, investigation and response procedures, training and roles and responsibilities.
5.3.1
Any change to the AQMP/ shall be submitted to the Council (Team Leader Central Monitoring) for certification. No activity reliant upon a change to the AQMP can be undertaken until the change has been certified. The Team Leader Central Monitoring shall be requested to respond to the proposed change within 10 working days from receipt of the change; otherwise the AQMP may be considered by the Consent Holder to be certified by the Council.
4.3
4.4
4.3.3
4.2 2.4, 6, 7
9
226
All works shall be undertaken in accordance with the certified AQMP/s.
Noted
227
Prior to the commencement of construction, and for the duration of excavation and construction associated with the Project which have the potential for significant dust emissions, the Consent Holder shall install, operate and maintain continuous dust monitoring undertaken using mobile instruments for the purposes of monitoring Total Suspended Particulates (TSP). The locations, durations and methods of TSP monitoring at each of ACZs A, K and M shall be in accordance with the details in the certified AQMP(s) required by Condition 222.
4.3
The dust monitoring instruments shall be fitted with an alarm system that sends a warning to the responsible person identified by the AQMP/s when dust concentrations exceed alert levels specified by the certified AQMP/s. The Consent Holder shall ensure that the responsible person, or other nominated person, is available at all times to take immediate action to reduce dust emissions from the site.
4.3
228
1.5
Sustainability
The Link Alliance is seeking an Infrastructure Sustainability Council of Australia (ISCA) Infrastructure Sustainability (IS) Rating. Further details can be found in the CEMP and Sustainability Rating Management Plan. Project sustainability requirements that relate directly to this AQ DWP are included
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Air Quality Delivery Work Plan in Appendix B. These requirements are imbedded within this AQ DWP 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 and consent requirements.
1.6
DWP Review and updates
This AQ DWP is a live document that will be reviewed at least annually, or as a result of a material change to the Project, or to address unforeseen adverse air quality effects arising from construction, or unresolved complaints. Any material changes to this AQ DWP must be certified by Auckland Council prior to any on-site activity reliant upon the change commencing. Refer to the CEMP for further detail on the review and updating process.
1.7
AQ DWP Author
This AQ DWP has been prepared by Andrew Curtis who is a Technical Director at AECOM specialising in air quality.
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2.
Karangahape Early Works 2.1 Overview of Works
Early works will be undertaken at the new Karangahape Station site to enable and provide for the subsequent main construction works. The early works are detailed in the CEMP. An overview of the work is provided in Table 2-1. Table 2-1: Overview of Karangahape Early Works
Works location
Overview of construction activities
Beresford Square / Pitt Street
· Relocation of network utilities located within the footprint of the new Karangahape Station in Beresford Square / Pitt Street; · Removal of street trees and the demolition of the café / toilet in Beresford Square; · Establishment of the Beresford Square Construction Support Area to provide site offices, construction vehicle parking, laydown areas and storage of plant and equipment etc.; · Closure of Beresford Square to vehicle traffic (other than construction traffic) while retaining pedestrian and cycle access; and · Removal of existing street furniture where required, such as seating and street lighting (to be replaced with temporary lighting).
Mercury Lane
· Relocation of network utilities located within the footprint of the new Karangahape Station in Mercury Lane; and · Establishment of the Mercury Lane Construction Support Area to provide site offices, construction vehicle parking, laydown areas and storage of plant and equipment etc. · Construction of the Mercury Lane temporary working platform.
It should be noted that the demolition of buildings and above ground structures within the Mercury Lane Construction Support Area is authorised by the CRL Enabling Work Outline Plan – Karangahape Road Demolition Works (Council reference OPW60339200), confirmed by Auckland Council in June 2019. Those works do not form part of this AQ DWP.
2.2
Discharges to Air
The main potential discharges to air arising from the construction activities discussed above is particulate matter (dust). The following dust generating activities from the Karangahape Station early works have been identified: · · · · · · · · Page 11
Dust associated with demolition of the Beresford Square café and toilets; Breaking up and excavating existing road surface concrete and asphalt; Excavation of trenches, and spoil removal; Excavation of launch and receiving pits for directional drilling; Storage of excavated spoil and imported fill (up to 24 m³, if necessary); Movement of vehicles in the work areas; Backfilling of the utility relocation trenches; Excavation contouring of Mercury Lane CSA and construction of Mercury Lane Station temporary work platform (including the importation / use of fill material); and | Karangahape Station Early Works
Air Quality Delivery Work Plan ¡
Contouring of Beresford Square CSA.
In addition, there will also be discharges of combustion related air pollutants from mobile plant and diesel generators. These include oxides of nitrogen (nitric oxide (NO) and nitrogen dioxide (NO2)), carbon monoxide (CO) and volatile organic compounds (VOC).
2.3
Sensitive Locations
Due to the proximity of pedestrians, and businesses to the works, all locations within 100 m of the areas of the designation in which the early works will be undertaken are considered sensitive1 to the effects of dust that have the potential to result from the works. In addition, any location within 100 m of the areas of the designation in which the early works will be undertaken where people live is considered a sensitive location, specifically the residences in 1 Beresford Square, the George Court building on Mercury Lane and the houses on East Street.
2.4
Key Personnel
The key personnel responsible for implementation of this AQ DWP are identified in Table 2-2. However, all site personnel are responsible for following the requirements of the AQ DWP. Refer to the CEMP for further detail on roles and responsibilities. Table 2-2: Key Personnel and Contact details
1
Role
Name
Karangahape Station Project Manager
Jonathan Hill
Karangahape Station Construction Manager
Dan Trotman
Environmental and Sustainability Manager
Sarah Sutherland
Link Alliance Karangahape Early Works Air Quality Specialist
Andrew Curtis
Link Alliance Communication and Engagement Manager
Rachel Blundell
The MfE has defined the sensitivity of different land uses in its Good Practice Guide for Assessing and Managing Odour in New Zealand. These definitions apply equally to the effects of dust, with both high density residential and commercial/retail areas considered to have high sensitivity. Page 12 | Karangahape Station Early Works
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3.
Environmental Standards 3.1 Environmental Performance Standards
As required by the CRL designation and resource consent conditions, the intention of this AQ DWP is to ensure that construction air quality effects are kept to a practical minimum, recognising the sensitivity of the environment within which the works are being undertaken. Generally, the compliance measure used in construction processes is that dust and other air discharges do not result in “off-site” nuisance, where off-site in this case is defined as being outside of the CRL designation. Because a “dust nuisance” cannot necessarily be identified until it has occurred, there are numerical guidelines that can be used in conjunction with Total Suspended Particulate monitoring to identify levels of dust that are likely to be considered a nuisance. These values, developed by the Ministry for the Environment (MfE), are set out in Table 3-1, together with additional values to deal with short term emissions that are most likely to result in effects. Table 3-1 also contains Trigger levels for odour, wind and dust deposition. Table 3-1: Environmental Trigger Levels for Air Discharges
Discharge
Trigger Level
Action
Dust Monitoring
Trigger values for Action 160 μg/m³ (1 hour average) 60 μg/m³ (24 hour average)
Implement requirements of Section 5.3.3 and any additional mitigation measures identified in Section 6.
Dust Deposition
Evidence of dust on windows (a finger run down the glass leaves a clear line) Dirt on clean washing
Implement any required mitigation set out in Section 5.
Odour
Presence of odour that is out of character with environment (e.g. smell of refuse in a residential area)
Implement any monitoring in Section 4.7 and mitigation set out in Section 5.
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4.
Monitoring Requirements 4.1 Dust Monitoring
The overall approach to dust control is primarily based on visual monitoring in combination with targeted ambient dust monitoring; good management of the construction areas; and a rapid response to any of the triggers outlined in Table 4-1 and/or to any complaints received. Good practice focusing on pre-emptive measures will aid in the avoidance of significant dust emissions, or if dust emissions occur, the subsequent mitigation or remediation of any adverse effects.
4.2 Visual Inspection and Monitoring Methods General visual monitoring of all early works construction areas will be undertaken on a daily basis or potentially more frequently, if conditions change. This type of monitoring relates to the control measures described in Section 5 of this AQ DWP and will include pre-emptive measures to avoid dust emissions. Table 4-1 below describes the monitoring programme. Table 4-1: Visual Dust Monitoring Programme
Monitoring Activity
Frequency
Check weather forecasts for strong winds and rainfall to plan appropriate work schedule and dust management response.
Daily
Inspect construction exits and adjoining roads for the presence of dust deposition.
Twice daily
Observe weather conditions including wind and rain via observations and data outputs from weather stations.
Daily and as conditions change
Inspect all exposed surfaces for dampness.
Daily and as conditions change
Inspect stockpiles to ensure enclosure, covering, stabilisation or dampness. Ensure stockpile height is less than 3 m where possible or appropriate.
Daily and as conditions change
Inspect dust generating activities to ensure dust emissions are effectively controlled.
Daily and as new activities are commenced
Inspect watering systems (sprays and water carts) if used, to ensure equipment is maintained and functioning to effectively dampen exposed areas
Weekly
Monitor dust generating activities and water application rate (as required).
In winds over 5.5 m/s (11 knots or Beaufort Scale 3) at 1.5 m above the ground
Check for dust on local roads being used to access the site.
Daily
Inspect any wheel wash equipment to ensure effective operation.
Weekly
4.3 Instrumental Monitoring 4.3.1.
Dust
While the Karangahape early works are relatively minor in nature and scale, and in general instrumental dust monitoring is not required, the proximity of residential properties to the Mercury Lane CSA, particularly those on East Street, means that continuous dust monitoring at this location is Page 14
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Air Quality Delivery Work Plan required. It is proposed to monitor Total Suspended Particulate (TSP) concentrations at only one location (specific monitor location to be confirmed prior to the commencement of these works). The TSP monitor will be easily re-locatable, able to run without mains power supply and will employ optical nephelometry that works by directing a laser beam through a sample of air containing particulate and measuring the light scattered by the particles in the sample.
4.3.2.
Meteorological Monitoring
Meteorological monitoring for the early works will be based on visual observations, with site engineers considering the weather conditions on a daily basis or as conditions change, and not undertaking activities when wind speeds are greater than 11 m/s or 6 on the Beaufort force scale that might carry dust beyond the site boundary. The Beaufort Scale (Appendix C) will be used to determine wind speed.
4.3.3.
Dust Trigger Alerts
The section below identifies how dust trigger alerts will be managed when that type of monitoring does occur. The monitoring equipment will be set up with text alerts to key personnel in the relevant work zone, when dust concentrations exceed the Trigger values set out in Table 3-1, namely 160 µg/m³ as a 1hour average and 60 µg/m³ as a 24-hour average. At a minimum this will include: · · · ·
The Karangahape Station Project Manager; The Karangahape Station Construction Manager; The Environmental and Sustainability Manager; and The Karangahape Station Site Supervisor.
If personnel change then the Instrument Technician will be contacted to update the alerts. If a dust trigger alert is sent, one of the above staff members will immediately (within 30 minutes) respond and investigate the cause of the alert. This investigation will: · · ·
determine if the alert is real and not caused by equipment malfunction; identify the source of dust; and check to see that all of the required mitigation measures are being implemented.
If it is determined that construction activities are the cause of dust and that mitigation measures are not effective at controlling dust, the Dust Contingency Measure outlined in Section 5.8 of this DWP shall be implemented. If these measures fail to effectively manage dust to acceptable levels, works will be halted until it can be determined why dust emissions are occurring and what additional mitigation measures are required to control ambient dust to acceptable levels. The findings of the investigation shall be recorded in the Air Quality Diary (refer Section 8.1 of this AQ DWP).
4.4 Monitor Locations The TSP monitor will be located on the eastern boundary of the Mercury Lane CSA, potentially in the same location as that proposed during the demolition works (which are subject to a separate AQ DWP). However, the final location will be determined once the demolition works are complete.
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4.5 Monitoring Data All monitoring data from the TSP monitor will be available to project staff on-line, once that equipment is installed.
4.6 Monitoring Equipment Maintenance When installed, the TSP monitoring equipment will require periodic maintenance. The monthly maintenance of the equipment will be carried out by either site personnel, who have received appropriate training, or an Instrument Technician. Maintenance and calibration will be carried out on the schedule specified by the equipment supplier by an Instrument Technician familiar with the equipment installed. In the event that there is an equipment malfunction, or the equipment needs to be relocated for some reason, then the Instrument Technician will attend to this.
4.7 Monitoring for Hazardous Air Pollutants While no specific areas of contaminated material have been identified near to the early works area, should this material be encountered (refer to the Contamination DWP), the procedures provided in the Contamination DWP will be followed, which may necessitate the requirement for air monitoring.
4.8 Odour Monitoring Odour monitoring will be undertaken when it is considered likely that odorous material will be encountered (such as the excavation of contaminated materials). The decision to undertake monitoring will be made by the Environmental and Sustainability Manager. The frequency of monitoring will be dependent on the nature / scale of the source, location in relation to sensitive receptors, and meteorological conditions during exposure. Odour scouting will occur: · ·
If potentially contaminated material is excavated and loaded into trucks for off-site disposal; and/or If odour complaints have been received.
The Environmental and Sustainability Manager will ensure that at least one person in each work area is trained as an odour scout. This monitoring will involve the odour scout being downwind of the works and assessing odours on the intensity scale set out in Table 4-2. Where odours are identified as being “Distinct” and above, and the odour characteristic unpleasant, mitigation measures will be implemented (refer Section 5.6 of this AQ DWP). All observations shall be recorded in the daily Air Quality Diary (refer Section 8.1 of this AQ DWP). Table 4-2: Odour Intensity Scale
Intensity Scale
Criteria
0
No Odour
1
Very Weak
2
Weak
3
Distinct
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Intensity Scale
Criteria
4
Strong
5
Very Strong
6
Extremely Strong
The odour scout will reassess the level of odour once the mitigation measures have been implemented. If the odours are still ‘Distinct’, further mitigation will be implemented, and / or the works halted until more conducive meteorological conditions are present, i.e. not blowing towards the sensitive receptor. If it is suspected that sources upwind of the works are responsible for any odour then the odour scout will make appropriate observations and document this also.
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5.
Operating Procedures
There are a range of routine measures that will be used on the site to manage and mitigate the effects of discharges of dust, odour or construction vehicle exhaust emissions. Additional mitigation may also be required in the event that: · · ·
Monitoring indicates that abnormal discharges of dust are occurring; Weather conditions are changing such that dust or odour discharges are more likely as determined using the Dust Risk Index; and / or Complaints are received regarding discharges of dust, odour or construction vehicle exhaust emissions.
All processes on the worksite will be implemented, operated, maintained, supervised, monitored and controlled so that any emissions authorised by the resource consent are maintained at the minimum practicable level. If the available mitigation methods are unsuccessful in controlling discharges (i.e. dust and odour) that cause significant adverse effects on receptors beyond the works boundary, then activities causing the discharge will be suspended until adequate mitigation can be put in place.
5.1 General Methods of Dust Control Dust control methods are generally associated with either reducing the potential for dust generation and transport associated with the activities described in Section 2 of this AQ DWP. General measures that will be employed during the early works to control dust from construction activities include: · · · · · · · ·
Controlling dust from any excavation by placing material directly into trucks where possible; If material being excavated is very dry, using water sprays to increase surface moisture; If materials are placed in temporary stockpiles, use water in dry windy conditions to control the dust potential prior to removal off-site; Controlling dust from exposed surfaces: Placing limits on vehicle speeds; Limiting disturbance of soil or dusty materials: Reduction in vehicle movements and speeds and the use of lighter vehicles will also reduce disturbance and dust generation; Limiting area of exposed materials: Staging of works and minimisation of material exposure in works areas will reduce the potential for wind erosion; Maintenance of surface moisture content: Watering or wet suppression is used to dampen dry or dusty exposed areas; and Removing excavated spoil from site on a regular basis.
5.2 Dusk Risk Index One of the main potential air quality impacts comes from dust associated with the construction process. To provide better guidance to the Environmental and Sustainability Manager, Karangahape Station Construction Manager and Site Supervisor on the implementation of dust mitigation, the works will use a Dust Risk Index (DRI). The DRI process is described in Appendix D. A simple “traffic light” indication of dust risk will be posted in each work area, so that site staff are aware of the dust risk. Note for the early works the DRI is considered Low Risk. Page 18
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5.3 Dust Mitigation Measures The dust prevention methods recommended in Table 5-1 are methods that have been found to be effective for many sites across New Zealand. These methods can be used alone or in combination depending on the circumstances. Alternate methods may be employed after the effectiveness of those methods is demonstrated and this AQ DWP updated accordingly. The scale of dust prevention methods required in a particular area will be dependent on the degree of risk that the dust would cause adverse effects on the surrounding area. The dust control methods for the various degrees of risk are described below.
5.3.1.
Methods of Dust Control – All Areas (Low Risk)
The dust prevention methods outlined in Table 5-1 will be used, as applicable, in all areas of the Project. The list is not exhaustive and additional methods may be found to be effective. Table 5-1: Dust management measures for all areas (Low Risk)
Source of Dust
Control
Stockpiles
·
Limit the height of uncovered stockpiles to reduce wind entrainment. Stockpiles exceeding 3 m in height have a higher risk of discharging dust;
· ·
Ensure that stockpiles do not exceed 24 m3 in size; Orientate stockpiles where possible in order to maximise wind sheltering as much as possible; Maximise shelter from winds as far as practicable; Keep active stockpiles damp at all times or bunker or cover stockpiles of fine materials; Dampen or bunker or cover inactive stockpiles if they are producing visible dust emissions.
· · · Unpaved Surfaces such as Roads and Yards
· · · ·
Sealed surfaces
· ·
Vehicles
· · · · · ·
Limit the amount of exposed surfaces as much as possible; Keep exposed surfaces damp. Typical water requirements for most parts of New Zealand are up to 1 litre per square metre per hour; Cover surfaces with coarse materials where practicable (e.g. ballast); Stabilise cleared areas not required for construction, access or for parking if liable to cause excessive dust during windy conditions. Methods may include placing metal on surfaces. Regular removal of dust through washing or vacuum sweeping – the frequency determined by visual inspection; Clear all spillages on sealed surfaces as soon as practicable. Limit vehicle speeds to 20 km/h through the works areas; Limit load sizes to avoid spillages; Cover loads of fine materials; Minimise travel distances through appropriate site layout and design; Minimise mud and dust track out from unsealed areas to sealed areas by using wheel cleaning facilities at site exits to sealed roads; Where necessary sweep public roads to remove any tracked dust.
Importation and Placement of Fill
·
Use water sprays as required during the placement and compaction of fill material to prevent dust generation;
Miscellaneous
·
Ensure sufficient water is available on site;
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Air Quality Delivery Work Plan
Source of Dust
Control · · ·
Earthmoving and Construction
· · ·
5.3.2.
Take account of daily weather forecast wind speed, wind direction and spoil conditions before commencing an operation that has a high wind potential; Install hoardings around CSAs sooner rather than later to assist by acting as wind breaks; Minimise the area of surfaces covered with fine materials. During periods of extreme dust risk, dampen areas that are to be earth-worked prior to any earthwork commencing. Allow time for penetration of the soil; Employ additional measures as practicable where dropping material from height, such as the use of water sprays; Stabilise exposed areas not required for construction, access or parking, along with completed fill and spoil areas as soon as practicable.
Further Methods of Dust Control – Moderate Risk
Moderate risk conditions require a greater level of dust control and attention to dust suppression. The methods outlined in Table 5-2 will be implemented in addition to the methods outlined in Table 5-1 during conditions presenting a medium risk. As above, this list is not exhaustive and other methods may also be employed to control dust. Table 5-2: Potential dust sources and control methods for moderate risk areas
Source of Dust
Controls (in addition to Low Risk Controls)
Vehicle Movements on unsealed surfaces
· ·
·
Loading, unloading and transport of dusty materials
Stockpiling
5.3.3.
·
Further limit vehicle speeds on unsealed surfaces; If wind speeds at the level of the unsealed surface are predicted in excess of 8 m/s (16 knots or Beaufort Scale factor 5), maintain unsealed surfaces in regular use in damp condition through surface watering (e.g. with water carts or fixed irrigation); Where a suitable water supply is not available for surface watering, synthetic dust suppressants may be used as an alternative. The use of recycled oil-based suppressants is expressly prohibited.
·
Limit loading or unloading during windy conditions that cause dust to be emitted beyond the site boundary; Use water sprays to dampen material prior to and during unloading to minimise dust generation if unloading needs to occur; Limit vehicle speeds on unsealed surfaces.
·
Bunker or cover stockpiles of fine, dry materials.
·
Further Methods of Dust Control – High and Extreme Risk Conditions
The greatest attention to dust control will be paid in extreme risk conditions and this is reflected in the further control measures outlined in Table 5-3. These methods should be employed in addition to the measures outlined in Table 5-1 and Table 5-2 during high and extreme risk conditions. As above this list is not exhaustive and other methods may also be employed to control dust.
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Air Quality Delivery Work Plan Table 5-3: Potential dust sources and control methods for high and extreme risk areas
Source of Dust
Controls (in addition to Low and Moderate Risk Controls)
Vehicle Movements on unsealed surfaces
·
Maintain regularly used unsealed road surfaces in damp condition through surface watering in all wind conditions.
Earthmoving, excavation and construction
·
Maintain surfaces of active earthworks areas in damp condition. This should include pre-watering of earthworks surfaces, prior to excavation allowing enough time for moisture to penetrate the soil;
Stockpiling
· ·
Maintain active stockpiles in damp condition with regular watering; Dampen or bunker or cover inactive stockpiles if they are producing visible dust emissions; Utilise windbreak fences or temporary bunkers if they are producing visible dust.
·
5.3.4.
Equipment Malfunction
If construction equipment fails and causes accidental dust discharges, it will be shut-down immediately and the fault repaired and tested prior to being allowed to continue operation. If equipment associated with dust control fails the activities reliant on the equipment will be suspended until the fault can be repaired. The location, duration and time of any dust discharge caused by equipment failure will be recorded in the environmental dairy.
5.4 Review of Dust Mitigation When site staff are alerted to a potential off-site dust nuisance through any of the monitoring techniques described in Section 5 of this AQ DWP, or as a result of a complaint from a third party, the Construction Manager / Site Supervisor will immediately undertake a review of site activities to determine the source of the dust and implement such further mitigation as may be required in order to reduce the dust generation to acceptable levels. The Construction Manager / Site Supervisor will notify the Environmental and Sustainability Manager as appropriate. In general, the additional mitigation will be those measures set out in Tables 5-1 to 5-3. Once the additional mitigation has been implemented the Construction Manager / Site Supervisor will review the monitoring data to ensure that it has been effective.
5.4.1.
Sources of Information
The following are locations where information necessary for determining the DRI and general dust control can be obtained: · ·
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Site specific monitoring web site where TSP and meteorological data can be accessed (to be established); and, Met Service: http://www.metservice.com/towns-cities/auckland/auckland-central
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Air Quality Delivery Work Plan
5.5 Dust Control during Contaminated Material Handling While no areas have been identified that are expected to contain contaminated material, the Contamination DWP (Appendix O of the Karangahape early works CEMP) sets out in detail how contaminated material will be dealt with should it be discovered. Set out below is further clarification on the specific mitigation measures that can be used to minimise the potential for any effects associated with discharges to air from contaminated material. In general it is considered that the dust generation, monitoring and control procedures described above are also suitable for use during the excavation, handling and transportation of any contaminated soils encountered during the works. Because of the increased potential for effects associated with dust from contaminated material, it is assumed that there is an extreme dust risk associated with these works, and all appropriate mitigation measures will be implemented to minimise effects. Dependent on the location and the size of the excavation and nature of the contaminant this may include: · · · ·
Pre-wetting the area to eliminate the potential for dust generation, while taking care not to overwater and cause contaminated run-off; Where practical, directly loading contaminated soils into trucks for transport to off-site disposal locations, and ensuring that all trucks are covered; If stockpiling is necessary, ensuring they are damped or otherwise covered, particularly in dry windy weather conditions; and Carrying out ambient dust monitoring to assess the effectiveness of the control measures.
5.6 Odour Mitigation Measures Discharges of odour are most likely to occur from any contaminated material encountered during the works (refer to the Contamination DWP for further detail in this regard). Odour emissions will be monitored by the odour scout during the excavation of such material and the following techniques utilised if necessary: · · ·
Limiting the time that the odorous material in the excavation is exposed; Removing excavated odorous material from site as quickly as possible in covered trucks; and The use of odour masking agents, chemical counteractants or digestive deodorant sprays.
If significant odour is detected and the odorous material cannot be removed quickly, and odour masking agents, chemical counteractants or digestive deodorant sprays are not immediately available, the odorous material will be covered, and work in that area suspended until suitable mitigation measures can be put in place. Section 4.7 sets out the odour monitoring procedure.
5.7 Control of Vehicle Exhaust Emissions Further to operational controls mentioned in Section 5.2 , the following key actions will be carried out to minimise emissions from vehicle exhausts: ·
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All construction machinery used on the site will be maintained in accordance with manufacturers’ requirements;
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Air Quality Delivery Work Plan ¡
¡
Where excessive exhaust smoke is identified from any construction vehicle that vehicle will be serviced as soon as is practicable and taken out of use until such maintenance has been completed; and Unless warm-up or turbo maintenance procedures require it, construction vehicles will not be left idling while parked or unattended.
5.8 Dust contingency measures In the event that there is a significant dust emission that results in either complaints or concentrations of dust that are significantly greater than the trigger values set out in Table 3-1, the Link Alliance will implement contingency measures, dependent on the nature of the complaint. These measures would be undertaken as a last resort if the source of the dust cannot be eliminated, in order to prevent build up. Measures may include the following options as appropriate (dependent on the level of dust emissions and adverse effects on a sensitive receiver): 1. Dust inside buildings or at a level which prevents windows being opened Following discussions with the building owner and/or occupiers, arrange to fit or retrofit dust filters to any building/apartment air supply systems. Where a building or specific apartment does not have an existing air supply system, then such a system will be installed, and all reasonable costs associated with the installation, operational and maintenance costs while the project is occurring. 2. Dust on the outside of buildings Arrange for the exterior of the building to be cleaned.
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6.
Communication with Affected Parties
Communication and consultation with affected parties and the wider community in vicinity of the early works will be regular and ongoing. Methods to facilitate communication will be through the Karangahape Community and Business Liaison Group, which will meet at least every three months during construction works, and through the methods discussed in Sections 6 and 7 of the Karangahape early works Communication and Consultation Plan (CCP) (Appendix G of the CEMP). These measures include engagement tools such as publications, phone calls, use of the CRL website to provide updates, signage, and advertising material. One on one engagement may also be used to engage with affected parties.
6.1 Complaints Although the measures described in this AQ DWP are aimed at avoiding complaints regarding discharges to air, complaints may still be received from members of the public during the works. Complaints shall be recorded and promptly investigated to identify and resolve the cause of the complaint in accordance with the complaints response protocol detailed in Section 7 of the CCP.
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Air Quality Delivery Work Plan
7.
Environmental Training 7.1 Project Staff
To achieve effective implementation of this AQ DWP and ensure works are undertaken in accordance with this AQ DWP and the designation and resource consent requirements, all site staff (contractors and subcontractors) will undergo general environmental awareness training and training about their responsibilities relating to the activities under this AQ DWP. Training requirements are described in detail within the CEMP. Specific training requirements relating to this AQ DWP are outlined in Table 7-1. Table 7-1: Specific Training requirements in relation to AQ DWP
Training requirements
Frequency
Attendance
Introduction to the on-site monitoring equipment
As required & during new staff induction
All new staff members
Responding to complaints regarding dust and air quality concerns
As required & during new staff induction
Karangahape Station Construction Manager, delegated staff member and duty managers
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8.
Record Keeping 8.1 Air Quality Diary
Construction activities can be affected by a number of different external and internal factors, such as weather conditions or equipment malfunction, which can contribute to an increase of dust emissions. Various control and mitigation measures are to be carried out on the site in order to prevent such effects, and monitoring and inspection procedures will be used to assess the level of dust emissions both within the works site and beyond its boundary. Recording relevant monitoring and inspection results, as well as the conditions of external and internal factors, can help to assess if control measures are being effective and to define appropriate corrective or preventive actions in case any undesirable effects are detected. The procedures for recording a daily Air Quality Diary are detailed below: · ·
The Site Engineer will fill out the daily diary each day and maintain the record on site. The following information will be recorded in the daily diary: · · · · ·
Any dust control equipment malfunctions and any remedial action(s) taken; Results of the visual observations / inspections of dust emissions; General weather conditions during the day (i.e., windy, calm, warm, rain, etc.); The frequency of watercart and/or water sprinkling system use; and The date and signature of the person entering the information.
A copy of the daily Air Quality Diary will be kept on-site for the duration of works.
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Appendix A: Record of CLG, IPR and Auckland Council Comments A1. CLG Comments A Karangahape CLG meeting was held on 17th September to discuss the Karangahape early works and for the CLG to provide comments / feedback on the CEMP and sub-plans, including this AQ DWP. No comments were received in relation to this AQ DWP.
A2. IPR Comments The IPR comments were as follows: DWP section
Paragraph/ sentence
Comment
Resolution
4.3.2
The IPR suggested a change the following change to the wind speed trigger “greater than 11 m/s or 6 on the BS”.
Change accepted
4.3.3
The IPR requested confirmation of trigger levels and inclusion of the trigger level in the text.
Change accepted
4.2
IPR comment “If it is contaminated material there needs to be some assessment to establish if there are likely to be health effects for sensitive receptors. (What is the source of the contamination? Is it only a “ nuisance odour effect” or a public health effect. The odour intensity scale is not appropriate in this instance”
No specific areas of contamination have been identified. However, a new section has been added to deal with the potential for hazardous air pollutants associated with contaminated materials.
5.6
IPR question “What has the contaminated land report said about the possibility of finding material here?”
No specific sources of contamination have been identified.
A3. Auckland Council Comments The Auckland Council review comments were as follows: DWP section Table 3-1 and Section 4.3.3
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Paragrap h/ sentence
Comment
Resolution
There is a discrepancy in Table 3-1 and section 4.3.3 relating to the instrumental dust monitoring 24-hour average trigger value. This would be most appropriate at 60 µg/m³ as proposed in section 4.3.3, being in accordance with the recommendation of the Good Practice Guide for Assessing and Managing Dust (GPG:Dust, Ministry for the Environment,
Table 3-1 has been modified to remove any confusion over the trigger values.
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Air Quality Delivery Work Plan
DWP section
Paragrap h/ sentence
Comment
Resolution
2016). The proposed 1-hour average trigger value (160 µg/m³) is lower than the recommendation of the GPG:Dust, but is appropriate. I consider this discrepancy could be remedied by a minor edit to the AQDWP following certification if appropriate. Section 4.2
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Only a single instrumental dust monitor is currently proposed for the Mercury Lane CSA to comply with Conditions [designation] 59.3(a) and [air discharge consent] 227. I consider this acceptable for this early works package, but note that further instrumental dust monitors will be required for more significant dust generating activities at the Active Construction Zone in future (to be addressed in future by the ‘Main Construction Works’ package). During this early works package, visual dust monitoring will need to be carefully undertaken at the Beresford Sq area; section 4.2 of the AQDWP is adequate for this requirement.
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Air Quality Delivery Work Plan
Appendix B: ISCA Requirements Table B identifies the ISCA Credit Requirements relevant to this Air Quality DWP and where they are addressed in the document. Credit
Requirement*
Relevant Section of AQ DWP
DIS-4 Level 1
Measures to minimise adverse impacts to local air quality during construction have been identified and implemented
3, 4, 5, 6, 7, 8
DIS-4 Level 1
Monitoring of air emissions and/or air quality is undertaken at appropriate intervals and in response to complaints during construction
4
DIS-4 Level 2
Monitoring and modelling demonstrates no recurring or major exceedances of air emission or air quality goals
4, 5
Refer to the ISCA Rating Tool for full details of the requirement
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Other relevant Information / Comments
Also refer to Monitoring Results and Reports
Air Quality Delivery Work Plan
Appendix C: Beaufort Scale Beaufort Force
Specification on Land
Speed Knots
km/h
m/s
Less than 1
Less than 1
Less than 1
Calm
Smoke rises vertically.
Very Light
Direction of wind shown by smoke drift but not by wind vanes
1–3
1–5
0.3 – 1.4
Light Breeze
Wind felt on face, leaves rustle, ordinary wind vane moved by wind.
4–6
6 – 11
1.67 – 3
Gentle Breeze
Leaves and small twigs in constant motion, wind extends light flag.
7 – 10
12 – 19
3.3 – 5.3
Moderate Breeze
Wind raises dust and loose paper, small branches move.
11 – 16
20 – 29
5.6 – 8
Fresh Breeze
Small trees in leaf start to sway, crested wavelets on inland waters.
17 – 21
30 – 39
8.3 – 10.8
6
Strong Breeze
Large branches in motion, whistling in telegraph wires, umbrellas used with difficulty.
22 – 27
40 – 50
11.1 – 13.9
7
Near Gale
Whole tress in motion, inconvenient to walk against wind
28 – 33
51 – 61
14.2 – 16.9
8
Gale
Twigs break from trees, difficult to walk.
34 – 40
62 – 74
17.2 – 20.6
41 – 47
75 – 87
20.8 – 24.2
48 – 55
88 – 101
24.4 – 28
0 1
2
3
4
5
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Description
Slight structural damage occurs, chimney pots and slates removed. Trees uprooted, considerable structural damage occurs.
9
Strong Gale
10
Storm
11
Violent Storm
Widespread damage.
56 – 63
102 – 117
28.3 – 32.5
12
Hurricane
Widespread damage.
> 64
> 119
> 33
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Appendix D: Dust Risk Index One of the main potential air quality impacts comes from dust associated with the construction process The AQ DWP sets out some of the mitigation measures that can be used to control this. However there are work activities and locations where the need for dust mitigation is minimal and others where it is extremely important. To provide better guidance to the Karangahape Station Construction Manager, and site staff on the implementation of dust mitigation, a Dust Risk Index (DRI) may be used during the Karangahape Station early works, when deemed necessary by the Link Alliance Environmental and Sustainability Manager. This is a technique recently developed for the construction phase of the NZ Transport Agency Cambridge Expressway and Transmission Gully projects. The full Transport Agency version of the DRI is detailed below; however the Link Alliance may develop a simplified, works specific version going forward. The objectives of using the DRI are to highlight those areas and activities that are of higher risk of generating dust issues by: ¡ ¡
A systematic and consistent approach to risk identification in relation to dust generation; A simplification of decision making in relation to the application of dust mitigation techniques and procedures; and Improved Stakeholder satisfaction and a reduction of dust related complaints from them.
¡
Factors and Weighting Assumptions The DRI uses a simple approach to generate a number that identifies the risk of dust generation and potential issues. The greater the number, the higher the likelihood of dust related issues. The formula involves combining a number of factors together in the following ways: DRI = Sum(E+S+M+WS+D+A)*R*WD Where: E = Surface exposure. S = Stabilisation. R = Rainfall. M = Month of the Year. WS = Wind Speed. WD = Wind Direction D = Distance to nearest receiver. A = Construction Activity.
Surface Exposure This factor recognises that where material has been removed from the surface of the ground that dust is more likely to be generated than if the original surface is still in place. As such a value of 0 is used where the surface remains untouched and a value of 10 is used where the surface has been exposed and the vegetation removed, and a value of 50 is used when the exposed surface has been significantly disturbed. Page 31
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Stabilisation This factor recognises that surfaces that have been exposed, in the manner referred to above and then subsequently stabilised are less likely to generate dust. Stabilisation measures associated with this project include: · · ·
Water; Chemical dust suppressant; and Aggregate covers such as Gap TNZ40, Gap 65, Drainage 200.
As such a value of 0 is used where the surface is fully stabilised in a manner described above, 5 when there is some degree of stabilisation and a value of 10 when no form of stabilisation has been used.
Rainfall This factor recognises that dust issues are neutralised by the presence of sufficient rainfall, or the receipt of sufficient rainfall within the previous 24-48 hours. As such a value of 0 has been assigned where it is currently raining and 1 where 5 mm or more of rainfall has been received in the previous 24 hours. A value of 1.5 has been assigned where 5 mm or more of rainfall has been received in the previous 48 hours. A value of 2 is assigned when it has not rained for more than 2 days.
Month of the Year This factor recognises that certain periods of the year are more likely to be periods of higher risk due to low soil moisture levels or higher wind speeds. As such the winter and spring months of June to September are assigned a value of 0; a value of 5 is used for April, May, October and November; and a value of 10 for the months of December to March.
Wind Speed Wind speed is recognised as a significant factor. Increases in dust issues coincide with an increase in wind speed. The following weightings have been applied to the wind speed groupings: · · · · ·
0-9 km/h 0 10-18 km/h 10 19-27 km/h 50 28-36 km/h 200 Greater than 36 km/h 500
Wind Direction This factor recognises that the degree to which a stakeholder or sensitive receiver adjacent the Project is effected by dust is strongly influenced by the direction of the wind in relation to their position. Where the wind direction is such that the receiver is downwind of the works then a value of 1 has been assigned to the factor. However where the wind is blowing away from the sensitive receiver then the value assigned is 0. Given the narrow nature of the Project alignment it is accepted that a value of 0 is highly unlikely for most areas due to the close proximity of sensitive receptors.
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Distance to the nearest Sensitive Receptor Closely related to the direction and speed of wind, as determining factors for dust issues, it is recognised that the distance to the nearest sensitive receiver also contributes to the risk involved. As such a value of 100 has been assigned to this factor.
Construction Activity The final factor recognises that certain construction activities are more or less likely to contribute to dust related issues. As such the following groups of construction activities have been assigned differing values. Where there are other activities occurring, choose the most similar activity or contact the Environment Manager for guidance. · · · · · ·
No Activity Piling Operations Excavator cutting and shaping of natural ground Handling of Spoil Pavement Construction Fill Placement
0 1 5 5 5 20
Overall DRI Value Once the DRI has been calculated for a particular location it needs to be assigned to a risk value using Table E-1 Table E-1 Conversion Values for DRI to Dust Risk
DRI Value
Risk
0 to 250
Low
250 to 350
Moderate
350 to 500
High
Greater than 500
Extreme
Forecasting At the beginning of each week on a Monday morning a DRI forecast will be carried out in order to assist with planning of dust management mitigation measures for that week. The forecast will identify the likely DRI for each day Monday through Saturday. The forecast will then be disseminated to the construction teams and staff responsible for dust mitigation such as supervisors and water cart drivers. The information will allow a more focussed and proactive approach to dust control and mitigation.
DRI Review Process At the conclusion of each month, as part of the monthly environmental reporting the Environmental and Sustainability Manager will review the performance the works in terms of dust management. As part of this review, the effectiveness of the DRI will be assessed and any amendments to the DRI advised and commented on.
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Communication of the DRI One means of communicating the DRI to construction staff is via a warning board similar to that used to convey fire danger in rural areas. Therefore each work area will have a board in a prominent location such as beside the site office or canteen where the current DRI value is displayed.
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