WESTHAVEN MARINA EXTENSION ACOUSTIC ASSESSMENT Rp December 2017

Transcription

1 WESTHAVEN MARINA EXTENSION ACOUSTIC ASSESSMENT Rp December 2017

2 84 Symonds Street PO Box 5811 Wellesley Street Auckland 1141 New Zealand T: F: Project: WESTHAVEN MARINA EXTENSION Prepared for: Panuku Development Auckland PO Box Victoria Street West Auckland 1010 Attention: Phil Wardale Report No.: Rp Disclaimer Reports produced by Marshall Day Acoustics Limited are based on a specific scope, conditions and limitations, as agreed between Marshall Day Acoustics and the Client. Information and/or report(s) prepared by Marshall Day Acoustics may not be suitable for uses other than the specific project. No parties other than the Client should use any information and/or report(s) without first conferring with Marshall Day Acoustics. The advice given herein is for acoustic purposes only. Relevant authorities and experts should be consulted with regard to compliance with regulations or requirements governing areas other than acoustics. Copyright The concepts and information contained in this document are the property of Marshall Day Acoustics Limited. Use or copying of this document in whole or in part without the written permission of Marshall Day Acoustics constitutes an infringement of copyright. Information shall not be assigned to a third party without prior consent. Document control Status: Rev: Comments Date: Author: Reviewer: Issued - For Resource Consent 22 Dec 2017 Ben Lawrence Craig Fitzgerald

3 TABLE OF CONTENTS 1.0 INTRODUCTION PROJECT DESCRIPTION PERFORMANCE STANDARDS Operational Noise Construction Noise (Airborne) Construction Noise (Underwater) EXISTING ENVIRONMENT Overview Airborne Noise Underwater Noise CONSTRUCTION ASSESSMENT Methodology Airborne Noise Underwater Noise Underwater Noise from Dredging Construction Noise Management OPERATIONAL NOISE CONDITIONS OF CONSENT CONCLUSIONS APPENDIX A GLOSSARY OF TERMS APPENDIX B AUP OIP PLANNING MAP APPENDIX C HYDROPHONE AND RIGGING DETAILS Rp BL (Westhaven Marina Extension - Acoustic Assessment).docx 3

4 1.0 INTRODUCTION Figure 2: Artists Representation of Project Marshall Day Acoustics (MDA) has been engaged by Panuku Developments Auckland to undertake an assessment of acoustic effects for the proposed extension to the Westhaven Marina breakwater and causeway. This report assesses potential airborne and underwater noise associated with the construction and ongoing operation of the marina. The proposed activities are assessed against the relevant legislation, planning rules and existing environment. Vibration has not been addressed in detail because it is predicted to be negligible, and generally not perceptible, at nearby sensitive receivers during the construction and operation of the facility. A glossary of acoustic terminology is included in Appendix A. 2.0 PROJECT DESCRIPTION The proposal includes an extension of the north-western breakwater and causeway (via reclamation) to connect to the north-eastern breakwater (refer Figure 1 and Figure 2), as well as conversion of many existing moorings into new accessible berths. The project is to provide: Approximately 6,300m2 of new reclamation: o 60% will be hardstand used for access ways and 103 additional car parks o 40% will be used for cultural elements, landscaping and open space 117 new marina berths The reclamation is proposed to be constructed from mudcrete (a mixture of concrete and material dredged from a barge). New berths and promenade piles will likely be drilled, but allowance for vibro and impact piling methods is necessary. The piles are proposed to be either timber or concrete with steel casings. The site is bordered by harbour to the north and east, and the northern motorway (SH1) to the south and west. The St Marys Bay residential area is located approximately m south of the site. The Wynyard Quarter business district is located a similar setback to the east. 3.0 PERFORMANCE STANDARDS 3.1 Operational Noise Under the Auckland Unitary Plan Operative in Part (AUP OIP), Westhaven Marina is located in the Coastal Marina Zone (refer Appendix B for planning map). Land to the south is zoned Residential, and to the east is zoned Business. Figure 1: Aerial Map of Project Auckland Unitary Plan Operative in Part (AUP OIP) rule E requires that activities in the Coastal Marina Zone must not exceed 60 db LAeq at all times within the boundary of any other site in this zone. Site AUP OIP rule E requires that activities on land in the Coastal Marina Zone must not exceed the following noise limit within a residential zone: Monday to Saturday, 7am 10pm Sunday, 9am 6pm 55 db LAeq At all other times 45 db LAeq 60 db Leq (63 Hz) and 55 db Leq (125 Hz) 75 db LAFmax There are no applicable noise limits for activities in the Coastal Marina Zone received in nearby Business zones (e.g. Business City Centre Zone and Business Mixed Use Zone in Wynyard Quarter). However, the noise limits applying within the Business zones are generally lenient and accommodating of the marine industry activities. 3.2 Construction Noise (Airborne) AUP OIP rule E reproduces the construction noise limits from Tables 2 and 3 of New Zealand Standard NZS 6803: 1999 Acoustics - Construction Noise. Construction of this nature usually exceeds 20 weeks duration and the normal working hours are usually between 7.30am and 6pm, Monday to Saturday. Therefore, the relevant daytime construction noise limits are 70 db LAeq and 85 db LAFmax. Rp BL (Westhaven Marina Extension - Acoustic Assessment).docx 4

5 3.3 Construction Noise (Underwater) Overview Section F2.18 of the AUP OIP includes objectives and policies relating to the management of the adverse effects of underwater noise on marine mammals. Table F (A114) classifies underwater blasting, impact and vibratory piling, and marine seismic surveys as restricted discretionary activities. Therefore, an assessment of underwater noise effects is required for this project due to the use of impact and/or vibratory piling. The assessment would also need to address effects from any capital dredging works, but the rule specifically excludes underwater noise generated by the operational requirements of vessels (including cargo vessels, tugs, passenger liners, naval vessels and commercial fishing vessels), use of sonar, and temporary activities other than construction. Although there are no underwater noise standards, F (c) identifies specific matters for discretion and F includes various matters for assessment as follows: The health and well-being of marine fauna (including threatened and at-risk species) and people from the noise associated with the proposal The practicability of being able to control the noise effects The social and economic benefits to the community of the proposal The extent to which the adverse effects of the noise will be mitigated There is no New Zealand guidance on underwater noise effects. However, the US Department of Commerce National Oceanic and Atmospheric Administration has provided guidance for assessing the effects of anthropogenic (human-made) sound on marine mammals 1 (referred to as the NOAA Guidelines ). This US statute does not apply in New Zealand, but the NOAA Guidelines are provided to give context to the underwater noise assessment Species of Interest Based on our experience from other projects in the Waitemata Harbour, and in consultation with the project marine ecologist 2, bottlenose dolphins, common dolphins and orca have been identified as the primary species of interest. These species are all classified as mid-frequency (MF) cetaceans for the purposes of underwater noise sensitivity. We also understand, through anecdotal sightings, that a leopard seal is currently resident in Westhaven Marina. Leopard seals are classified as Phocid pinnipeds (PW) for the purposes of underwater noise sensitivity Marine Mammals Physiological Impacts The NOAA Guidelines identify the received levels above which individual marine mammals are predicted to experience changes in hearing sensitivity. These changes are either temporary ( Temporary Threshold Shift or TTS), or permanent ( Permanent Threshold Shift or PTS) 3. Auditory threshold shifts can be caused from peak exposure (high-level impulsive events such as pile strikes) or from cumulative exposure (lower noise levels over an extended period such as from vibro-piling or multiple pile strikes). The NOAA Guidelines provide TTS and PTS onset thresholds for mid-frequency cetaceans using peak and SEL cum assessment descriptors. The peak level is the highest un-weighted instantaneous pressure level recorded during the measurement period, whereas SEL cum is the species-weighted cumulative sound exposure level over a 24-hour period. The criteria are summarised in Table 1. Table 1: Summary of NOAA TTS and PTS Thresholds Thresholds 4 Species Threshold Type Impulsive (e.g. impact piling) Non-Impulsive (e.g. vibro piling) Mid-Frequency Cetaceans TTS 224 db Lpeak 170 db SELcum (mf) PTS 230 db Lpeak 185 db SELcum (mf) Phocid Pinnipeds TTS 212 db Lpeak 170 db SELcum (ow) PTS Marine Mammals Behavioural Impacts 218 db Lpeak 185 db SELcum (ow) 178 db SELcum (mf) 198 db SELcum (mf) 181 db SELcum (ow) 201 db SELcum (ow) Behavioural responses to underwater noise can vary significantly depending on species, the noise environment, and the frequency content of the noise source. These effects can range from temporary avoidance of the noisy area to disorientation or impeded communication. Relatively little is known about the thresholds above which there are likely to be behavioural impacts. As interim guidance, NOAA states that behavioural impacts can occur at levels of 160 db re. 1 Pa rms for impact piling, and as low as 120 db re. 1 Pa rms for vibratory driven piles depending on the noise environment. However, it should be noted that these thresholds are recognised by NOAA to be conservative, and are only interim criteria until formal guidance is available Criteria for Divers The US Navy (US Federal Register, 2002) states there are no adverse noise effects below 145 db re 1 Pa rms. However, changing heart rates or breathing frequency have been found to occur above 154 db re 1 Pa rms. Safety guidelines for human divers published in a NATO Undersea Research Centre (NURC) publication 5 recommends military divers should avoid areas where noise levels exceed 160 db re 1 μpa rms (125Hz 4kHz). This is considered an acceptable threshold for experienced divers near the proposed works and aligns with the marine mammal behavioural response threshold for impulsive sources (impact piling) above. 1 National Oceanic and Atmospheric Administration: Technical Guidance for Assessing the Effects on Anthropogenic Sound on Marine Mammal Hearing (July 2016) 2 Simon West, Bioresearches Group Ltd 3 TTS in humans can be likened to the muffled effect on hearing after being exposed to high noise levels such as at a concert. The effect eventually goes away, but the longer the exposure, the longer the threshold shift lasts. Eventually, the TTS becomes permanent 4 SEL thresholds are in db re 1 μpa 2 s and peak SPL thresholds are in db re 1 μpa 5 NATO Undersea Research Centre Human Diver and Marine Mammal Risk Mitigation Rules and Procedures, NURC-SP , September 2006 Rp BL (Westhaven Marina Extension - Acoustic Assessment).docx 5

6 4.0 EXISTING ENVIRONMENT 4.1 Overview Noise levels were measured in the project vicinity to quantify the existing noise environment. An airborne measurement was carried out at the closest residential receiver (MP1 on Figure 3), and underwater noise measurements were carried out in the harbour area surrounding the marina (MP2 MP4 on Figure 3). Figure 3: Existing Noise Environment Measurement Locations MP2 - Hydrophone MP3 - Hydrophone 4.3 Underwater Noise Underwater noise levels were measured at the three locations for a period of two weeks (17 November 1 December 2017). The locations are considered representative of the receiving environment near the marina. See Appendix C for hydrophone and rigging details. The existing underwater noise environment was generally controlled by vessel movements during the daytime. The measurements were also affected by tidal movements at low frequency (63Hz and below). Figure 4 presents a spectrogram of a typical day at MP3, with the controlling noise sources labelled. Figure 5 presents the measured RMS levels in 15 minute periods over the survey period, and Figure 6 presents the same results with noise below 63Hz excluded (i.e. tidal flow noise excluded). A summary table of the results including average levels, ranges and peak levels is shown in Table 3 overleaf. Figure 4: Spectrogram of a Typical Day at MP3 (db re. 1 μpa rms (1sec) in 1/3 octave bands) Vessel movements Tidal Flow Snapping shrimp Site MP4 - Hydrophone Figure 5: Measured Noise Levels over Survey Period (db re. 1 μpa rms (15 min)) MP1 - Airborne 4.2 Airborne Noise An airborne noise measurement was undertaken adjacent to 12 Amaria Street, St Mary s Bay, which was the closest accessible receiver location. Weather conditions were fine during the survey, with little to no wind and 4/8 okta cloud cover. The noise environment was dominated by road traffic on State Highway 1, located between the Marina and the closest residential areas. The measurements are summarised in Table 2. Table 2: Summary of Measured Airborne Noise Levels Figure 6: Measured Noise Levels over Survey Period 63Hz and below excluded (db re. 1 μpa rms(15 min)) Measured Levels (db) Time Duration LAmax LAeq LA90 Noise Sources 2:27pm 2:44pm 15 min Traffic on SH1 (dominant), birds, traffic on Amiria St Rp BL (Westhaven Marina Extension - Acoustic Assessment).docx 6

7 Table 3: Summary of Measured Underwater Noise Levels Figure 7: Impact Piling Noise Contours Position Period Measured Levels (db re 1 μpa) RMS (15min) (10 Hz 24 khz) RMS (15min) (63 Hz 24 khz) Lpeak (1 sec) MP2 Day ( ) Night ( ) MP3 Day ( ) Night ( ) MP4 Day ( ) Night ( ) CONSTRUCTION ASSESSMENT 5.1 Methodology The marina extension is predicted to be constructed over a 12-month period. The main construction activities are shown in Table 4 below. Table 4: Summary of Construction Activities Activity Dredging Mudcrete mixing Placement of mudcrete and armour rock Piling Description Approximately 75,000m 3 of material will need to be dredged for the reclamation Dredged material is mixed with cement, likely on a floating barge 13,000m 2 mudcrete foundation will be formed on the sea bed, with armour rock placed on the sloping faces Installation of piles for berths, pontoons and promenade using either drilled, impact or vibropiling methods 5.2 Airborne Noise The closest occupied building within the Marina is the Royal New Zealand Yacht Club facility to the west of the breakwater extension. The closest noise sensitive receivers outside the Marina is in St Mary s Bay, approximately 600m to the south of the works area. Impact piling is predicted to be one of the loudest, and the most intrusive, construction activity. Noise contours for impact piling are included as Figure 7. In summary, construction noise is predicted to readily comply with the relevant daytime noise limits, Monday To Saturday. Furthermore, construction would rarely be audible in residential areas due to the high ambient noise levels generated by State Highway 1 road traffic noise. Rp BL (Westhaven Marina Extension - Acoustic Assessment).docx 7

8 5.3 Underwater Noise Overview Piling is predicted to produce the highest levels of underwater construction noise. Noise levels are dependent on the installation method (impact, vibro or drilled), pile type (steel, concrete or timber), pile size and mitigation. Noise propagation underwater is dependent on the bathymetry in the project vicinity and seafloor properties (rock, sand, mud etc.) Source Levels Comparable reference measurements 6 for the different pile sizes are summarised in Table 5. The equivalent species-weighted cumulative SEL 7 has also been calculated in each case. Table 5: Pile driving underwater noise levels Size and Method Source Levels (db re 1μPa at 10m) Vibratory driven 600mm steel Impact driven 600mm steel * Based on installation of 6 piles per day Noise Modelling Details Peak RMS SELSS SELcum (MF) SELcum (PW) 2 hours of driving/day* N/A strikes/day* Modelling of impact piling noise levels has been undertaken using dbsea, which is a 3D underwater noise software that enables spatial visualisation for the various zones of influence. The model inputs are summarised as follows: Bathymetry provided by BECA and supplemented by data from LINZ Source spectrums based on in-water measurements of impact driven steel piles 8 between 20Hz 20kHz, scaled to the levels provided in Table 5 The noise contours are calculated using a Parabolic Equation ( PE ) solver for frequencies below 2kHz and a Ray Trace solver above 2kHz. The cross over is considered suitable for depths of between 5 and 20m found in Waitemata Harbour Seafloor is assumed to be mud with sandstone beneath, and the speed of sound is assumed to be constant in the water column Predicted Zones of Influence The predicted zones of influence for the proposed piling works are presented in Table 6. These zones are based on the criteria provided in the NOAA guidelines (refer Section 3.3.3). The zones of influence have been provided as distances from the pile being installed. Table 6: Zones of Influence Species Threshold Vibro-piling (600mm steel piles) Zones Impact piling (600mm steel piles) All species PTS peak Below criteria Below criteria TTS peak Below criteria Below criteria Behavioural response 180m 230m Mid-frequency cetaceans TTS cumulative exposure 100m 70m Phocid pinnipeds PTS cumulative exposure <10m 60m TTS cumulative exposure 200m 230m Noise levels from the proposed piling works are predicted to be below the thresholds for peak PTS for both midfrequency cetaceans and phocid pinnipeds, and the PTS cumulative exposure is not predicted to be exceeded for mid-frequency cetaceans. For phocid pinnipeds (i.e. the leopard seal), the cumulative PTS threshold is predicted to be exceeded within 60m of the impact piling rig. The TTS thresholds for peak levels are not predicted to be exceeded. However, there is a potential for TTS from cumulative exposure if a marine mammal is within 100m of any vibro-piling or 70m of any impact piling, and for a phocid pinniped within 200m of vibro piling and 230m of impact piling. Potential behavioural response is expected within 180m 230m of the piling location, beyond which masking and audibility effects may also be apparent. However, the it is understood that the Waitemata Harbour is not a critical habitat for the identified species of interest. They are transient occupants rather than permanent residents of the harbour. Furthermore, the piling activities are of a temporary nature. Figure 8 graphically illustrates the underwater noise management zones for both types of piling. Overall, the underwater noise effects from piling activities are considered reasonable with the application of a suitable construction noise management plan (refer Section 5.5). 5.4 Underwater Noise from Dredging Underwater noise from backhoe dredging is primarily produced by the barge engine and propeller cavitation during transit to and from the dredging and disposal areas. There is also noise generated by excavation activities, such as the excavator bucket striking the seabed, however, this is negligible and not considered further. Measurements of dredging vessels 9 indicate that source levels can range from db re 1 μpa rms at 1m. These source levels would be similar to the majority of medium to large size vessels currently travelling in the Waitemata Harbour, and while the dredging would operate for longer periods in the same location, it is considered that the overall level and character would be generally comparable to existing vessel movements. The potential noise effects are considered to be local, behavioural (as opposed to physical trauma) and comparable in scale to existing marina vessel activities. 6 Impact driven concrete and timber piles California Department of Transportation: Technical Guidance for Assessment and Mitigation of the Hydroacoustic Effects of Pile Driving on Fish (Nov 2015), Table VI-1 7 The cumulative sound exposure level is the total sound energy over a 24-hour period normalized to 1 second. This parameter removes the duration component from the noise level, allowing impulsive and non-impulsive noise sources such as impact and vibratory piling to be compared. 8 ITAP Institut für technische und angewandte Physik GmbH: Spektren der Vibrationsramme beim Umspannwerk (2011) 9 Terra et Aqua, Number 144, September 2016: Dredging Sound Levels, Numerical Modelling and EIA Rp BL (Westhaven Marina Extension - Acoustic Assessment).docx 8

9 Figure 8: Underwater Management Zones Piling location Rp BL (Westhaven Marina Extension - Acoustic Assessment).docx 9

10 5.5 Construction Noise Management The following procedure should be implemented to manage the effects of underwater noise on marine mammals and divers: Undertake visual monitoring 30 minutes prior to commencing piling operations to ensure there are no marine mammals and divers in the area Use a wooden (preferable) or plastic dolly for the steel piles Use soft starts (gradually increasing the intensity of impact piling) and minimise duty cycle Undertake visual monitoring during piling operations to identify any marine mammals that enter the area Implement low power or shut down procedures when a marine mammal is identified within the TTS zones (based on the current methodology, Table 6 identifies a zone of up to 230m) This procedure is included as a proposed condition of any consent granted in Section OPERATIONAL NOISE Westhaven Marina is a large development consisting of around 2,000 berths and moorings, car parking and several commercial businesses. The proposed extension to the north of the existing marina is to provide 117 berths and 103 car parks, which would account for around 5% of the overall marina activities. The change in noise level associated with this increase in intensity of use is negligible. Furthermore, the nearest receivers are a significant distance away and their noise environment is dominated by SH1 road traffic movements. Noise from the marina extension is unlikely to be discernible above the existing noise levels in the vicinity. 7.0 CONDITIONS OF CONSENT The following conditions of consent are proposed: 1. To manage underwater noise effects on marine mammals and divers: Undertake visual monitoring 30 minutes prior to commencing piling operations to ensure there are no marine mammals and divers in the area Use a wooden (preferable) or plastic dolly for the steel piles Use soft starts (gradually increasing the intensity of impact piling) and minimise duty cycle Undertake visual monitoring during piling operations to identify any marine mammals that enter the area Implement low power or shut down procedures when a marine mammal is identified within the TTS zones MDA report ( Rp , dated 22 December 2017) identifies TTS zones of up to 230m. The zones must be updated prior to piling commencing and in response to monitoring results (refer condition 2). 2. Monitoring of underwater noise levels is to be undertaken during the first impact or vibratory pile driving works to confirm the predicted underwater noise levels and management zones. 8.0 CONCLUSIONS MDA has undertaken an acoustic assessment of the proposed Westhaven Marina Extension. In summary: The existing noise environment is generally controlled by SH1 road traffic Marina noise is predicted to comply with the relevant limits and the noise effects are negligible Construction noise is predicted to comply with the relevant airborne noise limits Underwater noise effects should be managed by implementing low power or shut down procedures for the piling works when a marine mammal and diver is identified within the TTS zones Conditions for any consent granted are proposed in Section 7.0 Rp BL (Westhaven Marina Extension - Acoustic Assessment).docx 10

11 APPENDIX A GLOSSARY OF TERMS db dba L Aeq (t) L A90 (t) L Amax L peak SEL TTS PTS Ambient Special Audible Characteristics NZS 6801:2008 NZS 6802:2008 Decibel (db) is the unit of sound level. Expressed as a logarithmic ratio of sound pressure (P) relative to a reference pressure (Pr), where db = 20 x log(p/pr). The convention is a reference pressure of Pr = 20 Pa in air and Pr = 1 Pa underwater. The unit of sound level which has its frequency characteristics modified by a filter (Aweighted) so as to more closely approximate the frequency bias of the human ear. A-weighting is used in airborne acoustics. The equivalent continuous (time-averaged) A-weighted sound level. This is commonly referred to as the average noise level. The suffix "t" represents the time period to which the noise level relates, e.g. (8 h) would represent a period of 8 hours, (15 min) would represent a period of 15 minutes and ( ) would represent a measurement time between 10 pm and 7 am. The A-weighted noise level equalled or exceeded for 90% of the measurement period. This is commonly referred to as the background noise level. The A-weighted maximum noise level. The highest noise level which occurs during the measurement period. The peak instantaneous pressure level recorded during the measurement period (normally not A-weighted). Sound exposure level (SEL) is the constant sound level acting for a reference period (typically a one second period in air and a 24 hour cumulative period underwater denoted by the addition of subscript cum ). It is the time-integrated, soundpressure-squared level. SEL is typically used to compare transient sound events having different time durations, pressure levels and temporal characteristics. Temporary Threshold Shift (TTS) is the temporary loss of hearing as a result of exposure to sound over time. Exposure to high levels of sound over relatively short time periods will cause the same amount of TTS as exposure to lower levels of sound over longer time periods. The mechanisms underlying TTS are not well understood, but there may be some temporary damage to the sensory hair cells. The duration of TTS varies depending on the nature of the stimulus, but there is generally recovery of full hearing over time. Permanent Threshold Shift (PTS) is the permanent loss of hearing caused by some kind of acoustic or trauma. PTS results in irreversible damage to the sensory hair cells of the ear, and thus a permanent loss of hearing The ambient noise level is the noise level measured in the absence of the intrusive noise or the noise requiring control. Ambient noise levels are frequently measured to determine the situation prior to the addition of a new noise source. Distinctive characteristics of a sound which are likely to subjectively cause adverse community response at lower levels than a sound without such characteristics. Examples are tonality (e.g. a hum or a whine) and impulsiveness (e.g. bangs or thumps). NZS 6801:2008 Acoustics Measurement of environmental sound NZS 6802:2008 Acoustics Environmental Noise APPENDIX B AUP OIP PLANNING MAP APPENDIX C HYDROPHONE AND RIGGING DETAILS Soundtrap 201 hydrophones were used for the underwater noise measurements. The hydrophones measured over a frequency range of 10Hz 48kHz. The figure below shows the rigging arrangement. >5m Surface buoy Residential Zones >5m Sub-surface buoy 1 2m Site Coastal Marina Zone Hydrophone 2 10m (approximately half water depth) Anchors / weights Antenna Business City Centre Zone Hydrophone Rp BL (Westhaven Marina Extension - Acoustic Assessment).docx 11