STATEMENT OF EVIDENCE OF DR BRIAN STEWART (ECOLOGY PEER REVIEW AND TURBIDITY) 12 FEBRUARY 2018

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1 BEFORE THE NORTHLAND REGIONAL COUNCIL IN THE MATTER OF the Resource Management Act 1991 ( RMA ) AND IN THE MATTER OF APPLICATION NO. a resource consent application by The New Zealand Refining Company Ltd under section 88 of the RMA to deepen and realign the Whangarei Harbour entrance and approaches APP STATEMENT OF EVIDENCE OF DR BRIAN STEWART (ECOLOGY PEER REVIEW AND TURBIDITY) 12 FEBRUARY 2018 ChanceryGreen PO Box 47516, Ponsonby

2 INTRODUCTION Qualifications and experience 1. My name is Brian Stewart. I am a trained marine biologist and hold a BSc in Zoology from the University of Canterbury; a Post Graduate Diploma in Marine Science from the University of Otago; and a PhD in Marine Science, also from the University of Otago. 2. I am a senior environmental scientist at Ryder Environmental Limited, an environmental consulting business based in Dunedin. Ryder Environmental Limited is a new company comprising the ecological staff that were, up until recently, employed by Ryder Consulting Limited. Prior to this I have held lecturing positions at the University of Otago and the University of Canterbury. 3. During the past 26 years, I have worked on a wide variety of marine and freshwater projects involving the assessment of macroinvertebrates, fish and algae, sedimentation rates in marine environments, environmental monitoring, and general water and sediment quality throughout the North and South Islands. 4. I have been contracted by private companies, regional councils and government departments to provide detailed ecological assessments of inter-tidal and sub-tidal habitats along the Otago coastline, and within Otago Harbour. I have also undertaken estuary habitat mapping for the Otago Regional Council, investigated the effects of sewage and stormwater disposal into the marine environment for the Dunedin City Council and have been contracted to supply numerous resource and ecological surveys for fishing interests in Otago. 5. I was, for the four years from 1996 to 1999, the manager of the biological monitoring programme for Meridian Energy in Doubtful and Milford Sounds. The aim of this programme was to determine effects on the fiord ecosystems of any sediments released as a result of the Manapouri Second Tailrace Project, by undertaking extensive annual dive surveys at multiple control and impact sites in the fiords. 6. I have, on several occasions, prepared evidence on behalf of the Marlborough District Council and other parties relating to mussel farm applications at numerous sites in the Marlborough Sounds. 7. In 2009 and 2010 I was engaged to prepare evidence on behalf of submitters opposed to Port Otago Ltd s (POL) Project Next Generation dredging programme. Once the programme had been granted consent POL engaged me to carry out the ecological monitoring programme that was a condition of the consent. 1

3 8. In 2011 I was retained by the Environmental Protection Agency as an expert advisor on marine ecological matters pertaining to the Waterview Connection motorway project in Auckland. 9. I am familiar with the site that is the subject of the application (the Crude Shipping Project, and Proposal ) and the surrounding locality. I have read what I consider to be the relevant parts of: the application material; submissions; and the Section 42A Report. Scope of role/evidence 10. Given my experience with the similar Port Otago project, I was initially engaged by the New Zealand Refining Company, trading as Refining NZ, to peer review the various draft ecological reports prepared in support of the Crude Shipping Project. In that role I provided comment and suggestions to the respective authors to address what I perceived as issues requiring clarification, or suggested improvements, to the reports. Thus, I provided comment on: The general robustness of the ecological assessments undertaken in relation to a fitfor-purpose appraisal of ecological parameters; The appropriateness of the assessments and how they compare with national and international best practice, when applied to projects of similar nature; and Whether the findings and recommendations from the studies are soundly based and reasonable. 11. My recommendations were addressed in the ecological reports which were filed with the AEE. 12. My evidence provides a summary of the conclusions I reached with respect to each of the ecological reports and an appraisal of overall risk assessment. 13. As the person who carried out field trials on the relationship between suspended sediment concentration and turbidity, Refining NZ also requested that I comment on the nephelometric turbidity unit (NTU) trigger values proposed by Dr Brian Coffey for the protection of nearby ecologically significant habitats during the dredging programme, and that now forms an integral component of the proposed three tier turbidity response mechanism. 14. I have read and agree with the AEE reports and expert evidence of: 2

4 (a) (b) (c) (d) (e) (f) (g) (h) (i) Brian Coffey (marine ecology); Graham Don (avifauna); Matt Pine and Jon Styles (underwater noise); Deanna Clement (marine mammals); Geraint Bermingham (navigational risk); Gavin Kemble (planning); Richard Boyd (commercial fishing) Robert Greenaway (recreational fishing); and Kevin Oldham (environmental spill risk). 15. I have also seen and agree with the proposed conditions that are relevant to my area of expertise. Code of Conduct 16. I confirm that I have read the Code of Conduct for Expert Witnesses contained in the Environment Court Practice Note (2014) and I agree to comply with it. In that regard, I confirm that this evidence is written within my expertise, except where I state that I am relying on the evidence of another person. I have not omitted to consider material facts known to me that might alter or detract from the opinions expressed. EVIDENCE STRUCTURE 17. In my evidence, I: (a) provide an executive summary of my key conclusions; (b) (c) (d) (e) (f) (g) (h) briefly summarise the relevant aspects of the Crude Shipping Project; provide an overview of my independent peer review findings; address matters relating to potential turbidity effects; address relevant submissions; address the s42a Report; comment on proposed conditions of consent; and summarise my conclusions. 3

5 EXECUTIVE SUMMARY 18. I believe the ecological (and associated) AEE reports and statements of evidence briefs are of an appropriately robust nature. The authors are all well qualified to make their assessments and have, in my opinion, recognised and assessed all relevant risks/effects and potential risks/effects. 19. Based on experience gained during similar projects, I believe that the turbidity thresholds (and the associated management responses) developed and recommended by Dr Brian Coffey and myself are robust and will safeguard the ecologically significant areas that are adjacent to the areas that will be disturbed by the proposed dredging and disposal operations. Further, if they are implemented in the manner proposed in Conditions 80-85, I am confident any significant ecological areas adjacent, or in close proximity, to the proposed dredging and disposal activities will not experience adverse effects due to increased turbidity. In that respect, any effects will be avoided in accordance with the direction provided by Policy 11 of the New Zealand Coastal Policy Statement OVERVIEW OF INDEPENDENT PEER REVIEW Benthic Ecology 20. Benthic ecology is likely to be the most widely affected by the project, either directly, by removal through excavation or burial by deposition, or indirectly, by fallout of sediments. The number of investigations carried out to determine the current state of the benthos, and likely effects on benthic habitats, reflect the need to fully understand the ecology of the area. 21. Initially, to identify zones of particular interest, a comprehensive literature review was undertaken (Coffey 2016). 22. Based on the literature review, a series of comprehensive environmental impact assessments were carried out on areas of benthos potentially affected by the Project. These included baseline surveys of the area adjacent to the dredged channel, proposed disposal areas (Kerr and Grace 2016, Kerr 2016, West and Bell 2015, West 2016) and of areas able to be used as reference sites against which future surveys may be compared (Kerr 2016). Also included were surveys of reef habitats that are located adjacent to areas that will be dredged (Kerr 2016). 23. It should be noted that the dredge and disposal areas themselves are not within any significant ecological areas. However, it is acknowledged that there are areas proximate to the dredged channel that are recognised as being ecologically significant 4

6 in the Northland Regional Coastal Plan (Northland Regional Council 2004) and the Proposed Regional Plan for Northland (Northland Regional Council 2017). These include the Motukaroro Island Marine Reserve. 24. Overall, I am satisfied that the assessments were carried out using established and robust methods and were of sufficient rigor to provide a clear understanding of the benthic communities surveyed. 25. Dr Brian Coffey collated the results of the literature review and the various benthic surveys in his ecological Assessment of Environmental Effects (AEE) (Coffey 2017). Dr Coffey s assessment report summarises the findings of the various ecological studies and includes what I consider to be a full summary of likely ecological effects, avoidance and mitigation measures, and final significance (Table 1, Coffey 2017). 26. Dr Coffey categorises likely effects on the environment as effects on the water column, effects on plankton, fish and wildlife, and effects on the adjacent coastal habitats. He recognises that habitats in the immediate footprint of dredge operations and disposal of spoil will be adversely affected, but notes that they will recover over a relatively short timeframe (i.e. 6 to 12 months for most soft bottom habitats, 6 to 24 months for longlived bivalve soft bottom habitats). Further, Dr Coffey believes that the relocation and/or erection of navigational aids will have no discernible effect. Based on my work with Port Otago Ltd, which included assessment of dredged soft bottom channel areas, I agree with these estimates. 27. However, it is further recognised that, due to maintenance dredging and associated disposal, communities that re-establish, may be similar to, but not identical to those that currently exist. Overall, considering the species and habitats affected are neither rare nor significant on a wider regional scale, I agree with Dr Coffey s conclusion that effects, although initially moderate, are likely to be extremely localised, transitory, and will ultimately fall away to be less than minor. 28. A similar conclusion (i.e. that effects will be localised, transitory and initially minor but will quickly drop away to being less than minor) is reached for soft bottom benthos outside the immediate dredging and disposal areas that may be affected by sediment plumes. 29. For regionally significant and ecologically important hard substrate and reef habitat, Dr Coffey recognises that prolonged exposure to high sediment loads may have adverse effects. 5

7 30. Dr Coffey, at sections 4.1.2b and 4.1.2d of his technical report, advises that activities associated with the Proposal are not expected to compromise water quality standards of the operative Regional Coastal Plan for Northland (the RCP) and that there is not expected to be a compliance issue with any of the clauses of performance standards (c) or (c). I agree. The ability to achieve these standards is based on, in large part, the application of appropriate mixing zones. I return to the rationale behind Dr Coffey s proposed mixing zones shortly. 31. Mr Kemble s advice to me is that the water quality standards applying within the proposed Regional Plan for Northland ( the prp ) are principally set out in policies D.4.3 and D.4.4 of that document. The standards set out in both policies apply instantaneously (i.e. they do not apply after reasonable mixing). With this in mind, I have considered these standards against the various disturbance activities that are proposed. My conclusions follow: a. The installation of the five new aids to navigation, and potentially the relocated aids to navigation may not be able to meet the turbidity standard of Policy D.4.3 because the process of installing new structures may cause turbidity at the site to change from its natural state. The area impacted in this way will be very localised, and will not, in my opinion, extend outside of a 20 metre (radius) circle from the point of discharge. b. The dredging activity will likely cause turbidity at the work site to change from its natural state and will therefore also compromise the turbidity standard of Policy D.4.3. c. The disposal activity will likely cause turbidity at the work site to change from its natural state, which will also cause it to cut across that aspect of Policy D Given this, my advice to Mr Kemble has been that the Proposal cannot meet the criteria that are set by Policy D.4.3, but, given the relative cleanliness of the substrate being dredged, I expect it to achieve those set by D Dr Coffey has suggested a raft of monitoring (following best scientific practice), mitigation, and compensation measures that will, if adhered to, ensure that any effects on these sensitive areas are avoided and/or mitigated. These include a 100 m mixing zone for reef areas (300 m for soft substrate), and clearly defined turbidity limits beyond such mixing zones. I consider that the proposed monitoring will contribute the data required to satisfy Method of the operative Regional Coastal Environment 6

8 Plan. Dr Coffey and I also proposed an undertaking to establish and support a Stream Care Group for Blacksmith s Creek and Estuary to compensate for the temporary reduction in benthic productivity due to the proposed works. This undertaking has since been embodied within the proposed Conditions With the proposed mixing zones in place, I believe that the activities associated with the Proposal will not cause coastal water quality standards, as specified in Policy D.4.3 of the proposed Regional Plan, to be exceeded. 35. I appreciate that the application is for a discretionary activity, and that, while neither policy D.4.3 nor Policy D.4.4 of the prp establish mixing zones, the RCP does. 36. I also note that rules C (b) and C.6.9.5(4) of the prp, which Mr Kemble advises apply to the installation of the aids to navigation, contain additional water quality considerations. Rule C (b), which applies to the act of installing the aids to navigation and is in addition to the requirement to comply with the standards set out in Policy D.4.3, does not stipulate sizes for mixing zones for permitted activities. It merely states: any activity must not: b) cause any conspicuous change in the colour of water in the receiving water or any change in horizontal visibility greater than 30% (after reasonable mixing) for more than 24 hours after the completion of the activity. 37. Rule C.6.9.5(4), which applies to the discharges associated with the installation of the aid to navigation, includes a mixing of 20-metre radius from the point of discharge. I have assessed the likely discharges associated with the aids to navigation against these standards, and am of the opinion that the criteria can be achieved in this instance. 37. I note, also that Policy D.4.8 of the prp states When determining what constitutes a reasonable mixing zone, use the smallest zone necessary to achieve the required water quality in the receiving water and ensure that the mixing zone is free from contaminant concentrations and levels of dissolved oxygen that cause acute toxicity. 38. I am of the opinion that when assessing the environmental effects of a discharge, it is appropriate to apply the criteria set out in Policy D.4.8 and have considered the mixing zones proposed by Dr Coffey accordingly. 39. In my experience, given the hydrodynamics of the areas being worked, the relative sensitivity of the habitats likely to be affected, and the general cleanliness of the substrate being dredged, the proposed mixing zones are the smallest practicable and 7

9 entirely appropriate. As a consequence, I am of the opinion that they comply with Policy D.4.8 of the prp. I also consider the 20-metre radius mixing zone that applies in Rule C.6.9.5(4) meets the criteria set out in Policy D.4.8, and therefore have recommended that it be applied to the consideration of the discharges and disturbances associated with the installation of the aids to navigation. 40. I also believe, given the general cleanliness and coarse nature of the substrate being dredged, that waters at the disposal sites will be maintained within their natural range outside the mixing zones. 41. Consequently, I am of the opinion that the threshold values and recommended responses proposed by Dr Coffey will be sufficient to protect sensitive areas beyond mixing zones and do not expect them to be adversely affected by the proposal. I am also of the opinion that the turbidity values and contaminant or dissolved oxygen concentrations within the mixing zone will not cause acute toxicity such that the lifesupporting capacity of coastal waters, as outlined in Policies (d), and (b) of the RCP, is jeopardised. 42. It is also my opinion that conditions outside the mixing zones will meet the criteria outlined in Rule C (b) of the proposed Regional Plan for Northland and sections 15B(1)(b) and15b(2)(b) of the Resource Management Act, and will be maintained within their natural range. Lastly, I note that Dr Coffey discusses the Resource Management (Marine Pollution) Regulations 1998 in section 6.4 of his technical report. I agree with his conclusion that the Proposal is expect to achieve the standards and criteria that are contained within these regulations. 43. Further, it is my opinion that any environmental effects within the mixing zones recommended by Dr Coffey for the dredging and disposal activities, and within a 20- metre radius of the aids to navigation will be very localised, of short duration, and will not adversely affect existing beneficial water quality dependant values. As a consequence, I am confident that the discharges are aligned with the outcome that is set out within Policy D.4.5 of the prp. I return to the proposed turbidity limits later in my evidence. 44. With respect to the relocation and/or construction of navigation aids, Dr Coffey concludes that any effects will be localised and of a temporary nature and will, ultimately, be less than minor. I agree with this assessment. 45. Lastly, Dr Coffey recognises that there may be overarching effects due to climate change, but that such effects are not expected to have any measurable effect on the 8

10 impacts of the capital works dredging programme or maintenance dredging programmes. Consequently, they do not alter the conclusions he has reached. I agree with this assessment. Avifauna 46. Graham Don, of Bioresearches, was engaged to assess avifauna in areas likely to be affected by the Proposal and to predict likely effects on the avifauna as a result of the dredging programme. Mr Don was also asked to recommend appropriate mitigation measures, if and where deemed necessary. 47. To this end a literature search was carried out (Bioresearches 2015) and extensive field surveys of bird populations, including little penguins, were undertaken around Whangarei Harbour and Bream Bay during 2015 and 2016 (Don 2016a,b) and, I understand, a further survey has been carried out more recently with respect to little penguins. 48. The literature review and surveys revealed a healthy and diverse avifauna with a number of the 34 species identified being listed as threatened or nationally at risk. 49. Breeding in Whangarei Harbour and Bream Bay edge habitat was reported for both threatened and at risk species comprising a wide range of bird groups including waders, gulls, terns, penguin, shags and shearwaters. 50. Overall it was concluded that there will be no loss of feeding or roosting habitat as a result of either the capital dredging programme, including relocation of navigational aids, or the maintenance dredging. 51. However, a number of potential adverse effects were identified. These included increases in turbidity, deposition of sediment on subtidal and intertidal habitats, increased vessel movements, an increase in vessel lighting, and generation of underwater noise, each of which may affect bird feeding, behaviour, and/or navigation. 52. The adverse effects from the above were considered less than minor in all instances apart from turbidity and lighting effects. In those cases, measures to mitigate these effects have been suggested. Such measures include: (a) (b) a lighting audit of dredge vessels in order to minimise effects on pelagic birds and in particular grey-faced petrel; targeted predator control programmes; and 9

11 (c) augmenting already existing breeding enhancement programmes (e.g. that run by the Bream Head Conservation Trust) by providing funding and/or materials for nesting boxes for, and monitoring of, appropriate species (i.e. little penguins, grey faced petrels); and 53. It is my understanding that predator control will commence not less than 6 months prior to the commencement of capital works dredging and will continue for 5 consecutive years and thus, effects of breeding enhancement will extend well beyond the period of capital works dredging. 54. Overall, I found the literature review and avifauna surveys to be carried out to an acceptable level of rigour and to provide a sound basis for assessing possible effects of the project on local bird populations. I agree with Mr Don s conclusions that with the proposed mitigation measures in place, any effects of the Proposal on avifauna will be less than minor. I also agree with his conclusions that the Proposal would not cut across any of the avifauna based policies that Mr Kemble traverses in his evidence. Acoustic Effects 55. Acoustic effects were assessed to inform Dr Clement s assessment of effects on marine mammals. Acoustic modelling is beyond my area of expertise, but has been assessed by Dr Matthew Pine, an underwater acoustics expert with 6 years experience in such matters, employed by Styles Group, Dr Pine identified that the three likely dredger types proposed will each have a different noise signal, and that will, in turn, be dependent on the type of substrate being excavated. 56. The noise generated will likely affect marine mammals, and, with low frequency sound expected to travel some distance from the point of generation, low-frequency sound sensitive cetaceans may be affected over a wide area. 57. With the detail such as specific type of dredge vessel yet to be confirmed, Dr Pine took the precautionary approach of using medium to large dredges as the basis for his modelling. Such dredges are expected to yield the loudest noise signatures, thus resulting in more conservative recommendations being made. I agree this approach is appropriate. 58. Likely effects on marine mammals were classified as permanent injury, temporary loss of hearing sensitivity, masking of usual sound perception, and behavioural changes. 10

12 59. Dr Pine concluded that injury from dredging associated sounds was unlikely, irrespective of dredger type or size. For temporary loss of hearing sensitivity, masking, or behavioural changes to occur, the critical distances to avoid effects ranged from 1 metre to 14.7 km, depending on species affected, type of dredge, substrate being worked, and location. 60. Noise from transport and disposal of excavated material was expected to be of short duration and not expected to exceed noise generated by large commercial vessels entering and leaving the harbour. 61. The general findings of the modelling were that the dredging works would have a potential short-term masking and/or behavioural impact within a limited radius of the operations. Marine Mammals 62. Clement and Elvines (2015, 2017) recognise that Whangarei Harbour and nearby waters are not considered ecologically significant in terms of feeding, resting or breeding habitats for any marine mammal species. Having considered these reports, and the rationale they express, I agree with their conclusions. 63. Nevertheless, the 2017 report outlines and assesses the potential effects of dredging and disposal activities on the relevant marine mammals in context of the Proposal and suggests a monitoring plan and possible mitigation measures. Dr Clement addresses these matters in her statement of evidence and these have been included in the proposed consent conditions. 64. Potential direct effects are identified as potential vessel strikes, increased underwater sound production, and possibly the risk of entanglement. Potential indirect effects are considered to include exposure to contaminants released in dredge spoil and changes in turbidity and to habitat that may affect feeding. A useful table (their Table 2, reproduced below) is provided that summarises effects and their likelihood. 11

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14 65. The monitoring programme recommended, and the proposed mitigation measures are, in my opinion, well-reasoned and sensible and, as far as I can ascertain, follow international best practice. 66. Dr Clement believes that any direct effects on marine mammals, such as vessel strike, entanglement and underwater sound will be low to de minimis. Given that a conservative approach was used by Dr Pine in modelling acoustic effects, I believe the mitigation measures recommended in the marine mammal report (Clement and Elvines 2017), and discussed by Dr Clement in her evidence, are appropriate. 67. Further, she concludes that indirect effects, such as turbidity and effects on prey species, will be minimal, of relatively short duration, and are not expected to be detrimental to marine mammals in the region. I agree with those conclusions. Summary/Conclusion 68. I have considered the current proposal against two other recent examples of dredging projects which have received resource consent, those being Port of Tauranga (PoT) and Port Otago Ltd (POL). 69. While Port of Tauranga undertook an ecological assessment for their dredging programme, it did not address marine mammals or birds. 70. Thus, the approach taken for the Proposal by Refining NZ is more aligned to that taken by Port Otago Ltd (POL) for their Next Generation dredging project (i.e. a number of appropriately qualified experts have been engaged to identify likely environmental effects of the project, as they relate to the particular author's area of expertise, in a broad range of ecological fields). 71. The overall conclusions reached are that for seabirds and marine mammals, effects are likely to be avoided in some instances, and less than minor, or of short duration in the vast majority of others. 72. For benthic communities there will be an unavoidable loss of a small percentage of soft bottom community within the dredged footprint and within the footprint of the disposal area. However, Dr Coffey points out the organisms found within this community are neither rare nor significant on a wider New Zealand scale and will recover within a relatively short (6 to 24 month) timescale, depending on substrate and fauna. I agree with this observation. 13

15 73. Rocky bottom reef communities are more significant ecologically, but, provided recommended trigger suspended solid concentrations are not exceeded, adverse effects on such communities are expected to be avoided. Indeed, where similar projects have taken place, (i.e. Port Otago and Port of Tauranga) monitoring has demonstrated that ecological effects have been negligible. 74. An overall risk assessment (e.g. Stewart 2011) is occasionally prepared for projects such as this. However, I am of the opinion that further risk assessment is unnecessary, given that the authors of the ecological reports have, in my opinion, recognised all the potential ecological risks and have suggested appropriate avoidance and/or mitigation measures, or have recommended a suitably precautionary approach. 75. Overall, I believe the ecological and associated reports submitted for review are of a comprehensive and robust nature. Each author has identified likely risks to organisms and or habitats within their area of expertise, assessed the likelihood of adverse effects occurring and suggested possible management practices that will avoid, remedy or mitigate those effects. 76. I agree with the conclusions reached by Drs Clement and Elvines (marine mammals), and Dr Coffey (benthic ecology) that neither Policy 11 (a) or (b) of the New Zealand Coastal Policy Statement (NZCPS) nor Policy of the Northland Regional Policy Statement (NRPS) will be contravened. 77. For avifauna Mr Don states that he believes NZCPS Policy 11 (a) and (b) would not be triggered at a population or regional level and, if triggered at a local level, can be mitigated to a point that any adverse effects are less than minor. Again, I agree with this conclusion. 78. Although the reviewed reports were written before Policy D.2.7 of the proposed Regional Plan for Northland was notified, I believe the conclusions reached by each of the experts meet the expectations outlined in Policy D.2.7 (3) b) and c) and D.2.7 (4) and (5). 79. Overall, based on the conclusions of the various ecological experts engaged, it is expected that cumulative effects from the Proposal on the ecology of Bream Bay and Whangarei Harbour will, in the long term (i.e. >24 months), be negligible. 14

16 TURBIDITY 80. Potential sediment plume effects within the dredging footprint between Home Point and the Motukaroro Island Whangarei Marine Reserve are, in my opinion, of greater significance than in the outer dredging footprint and at the two disposal areas. This is because the dredging footprint is immediately adjacent to high conservation value hard-bottom habitat, while the outer dredging footprint is surrounded by a less sensitive (soft-bottomed) receiving environment. 81. To protect adjacent communities from potential sedimentation effects, it is necessary to establish what their tolerance is to suspended solids concentrations, and the duration elevated suspended solids concentrations are likely to be present within the habitat those communities are occupying. 82. To determine this, historic records, proved by the Northland Regional Council (NRC), covering a period from 2005 to 2016 were examined to establish likely ambient turbidity within the lower Whangarei Harbour. However, these data are limited to just 72 data points over a 10-year period. 83. To more robustly record ambient turbidity in the area of the Proposal Refining NZ has deployed a series of four turbidity meters that recorded turbidity at two sites every 15 minutes since May See Figure 1 for example. 84. Results show that there is an ambient turbidity within the harbour of around 3 to 5 nephelometric turbidity units (NTU) with relatively regular fluctuations associated with tidal flows reaching up to 10 NTU. Causes of occasions when NTU levels exceed 10 are not always clear, but are often associated with rainfall and/or wind events. 85. The observed good health of benthic communities on rocky reef areas within Whangarei Harbour, despite occasional high turbidity (up to >120 NTU), demonstrates that such communities are relatively resilient. 15

17 Figure 1 Ambient turbidity (NTU) at near surface depths recorded adjacent to Motukaroro Island Marine Reserve during May, June and July High points generally coincide with heavy rainfall events. 86. To establish a relationship between NTU and total suspended solids (TSS) I undertook a series of laboratory and field trials using actual substrate that will be dredged during the Project (Stewart 2017). 87. The trials I carried out established that the overall relationship between NTU and SS was very close to 1:1, with some slight variability according to where cores used in the trial were collected (Figure 2). 16

18 Figure 2 Relationship between NTU and SS for all cores used in trial. 88. The trials also revealed that the vast majority of sediment was relatively coarse and dropped rapidly out of the water column within 25m of the release point. This is consistent with Tonkin and Taylor s (2017a) finding that dredged material will contain less than 6% of fine silts. 89. Based on my trial results, results from turbidity sonds deployed by Refining NZ, and results from similar situations (e.g. Port of Tauranga dredging monitoring and Port Otago Ltd dredging monitoring) Dr Coffey has suggested a series of turbidity thresholds for the proposed operations (Table 1) and recommended responses as below: Level 1: the reason for elevated suspended solids concentrations down-current of the operational dredge need to be investigated, Level 2: operational changes are required by the dredge to reduce down-current suspended solids concentrations, and Level 3: suspended solids concentrations down-current of the operational dredge result in dredge activities being stopped. 17

19 Table 1 Recommended turbidity thresholds (NTU) for the dredging programme. A and D relate to 6-hour average of one-minute interval records from fixed turbidity meters. B, C and E relate to hand-held turbidity meter readings as per Figure 17 of the AEE. (Adapted from Coffey 2017) * Provisionally based on RNZ data for location A between May and July ** based on Tables 3-4 of Tonkin and Taylor 2017b. 90. Given the ambient level of turbidity experienced near the most sensitive areas likely to be affected by sediment plumes, the suggested thresholds are, in my opinion, entirely reasonable and will ensure that the adjacent ecologically significant communities are protected from adverse effects. 91. It is expected that outside of the mixing zones suggested by Dr Coffey, and outside a 20-metre radius from the aids to navigation, water quality will be maintained within its natural range. Therefore, I do not expect activities associated with the Proposal will result in water quality outside those mixing zones that will fall outside the CA standard specified in Appendix 4 of the RCP, nor will they result in water quality that contravenes the water quality standards set in policies D.4.3 and D.4.4. Further, and as I have also noted, any effects within the mixing zones are not expected to cut across the policy direction that is set out within both the prp and the RCP. 92. It should be noted that the threshold levels suggested by Dr Coffey fall well below the maximum NTU levels experienced on regular occasions in Whangarei Harbour. 93. My support for the suggested thresholds is also based on the fact that such threshold levels are consistent with those used in monitoring at the Port of Tauranga (PoT) and in Otago Harbour where similar dredging programmes have been undertaken. 94. Indeed, the thresholds used by PoT have ensured that the communities at the entrance to Tauranga Harbour have not sustained any observable adverse effects after 18

20 exposure to dredge generated sediment plumes Warren et al. (2016). This is despite the dredging being much closer to the rocky habitats in Tauranga than what is proposed here, where at least a 100 metre separation will exist. 95. It is understood that should any of the thresholds be exceeded during the course of dredging and/or disposal associated with the Crude Shipping Project, Refining NZ will examine rainfall and wind data, along with data on dredge activity to determine the likely cause of exceedance, as specified in the Level 1 response above. 96. It is also my understanding that, should the exceedence not be attributable to extrinsic factors (e.g. high wind event, heavy rainfall event), Refining NZ will take appropriate action to ensure NTU values fall below the threshold level (i.e. Level 2 exceedence will likely involve an operational change to restore NTU levels to below the Level 2 threshold; for Level 3 exceedence dredging will be stopped and not resumed until NTU values fall below the Level 3 threshold).. RESPONSE TO SUBMISSIONS 97. I have read and considered the submissions relating to ecology/turbidity and set out my response below: (a) Mere Kepa has opposed the application on a number of grounds, including increased turbidity in the sea and contamination causing loss of seafood. As already pointed out, I am confident that the proposed mitigation measures and responses, and the particle size of the dredged substrate will ensure that effects on the benthos, and on shellfish will likely be less than minor. Additionally the very low levels of heavy metals in the substrate to be dredged mean contamination of seafood will be highly unlikely. (b) (c) Bream Head Conservation Trust (BHCT) supports the application predicated upon the imposition of a number of conditions that they outline in their submission. It is my understanding that the proposed mitigation and offset measures go some way toward meeting the BHCT s proposed conditions, particularly Condition 6a and b and Condition 7, by requiring Refining NZ establish and support conservation initiatives such as the establishment of a Blacksmith s Creek Care Group, and contributing towards predator control and breeding enhancement for pelagic birds. Bream Bay Coastal Care Trust has asked that consent be refused on the grounds that the Trust is concerned that there will be effects on the ecology of the 19

21 proposed dredge site and the greater Bream Bay marine environment; kai moana; on birdlife; on marine mammals, from lighting, and on marine reserves. As already stated, I believe proposed thresholds for turbidity and response actions will protect sensitive areas adjacent to the project site. Further, Dr Clements has pointed out that effects on marine mammals are likely to be de minimis. Mr Don is of the opinion that effects on avifauna, too, will be less than minor, but has recommended mitigation measures that will enhance local bird populations. Refining NZ recognises that there will be some short term effects on benthic productivity and has proposed a number of mitigation and offset measures that will compensate for this loss. It needs to be re-iterated that recovery to similar levels of diversity and abundance is expected within 6-24 months. (d) The Department of Conservation (DoC) opposes the granting of consent unless conditions are imposed that address the following concerns; known feeding and breeding habitat for birds, marine mammals and other wildlife monitoring of sediment rates; turbidity levels and contaminants within the Marine Reserve; monitoring benthic indicator species; monitoring of intertidal and subtidal algal and sessile invertebrate assemblages within the Marine Reserve; and appropriate baseline monitoring, triggers, and adaptive responses if adverse effects are detected within the Marine Reserve. The reports and evidence of Mr Don and Drs Clement and Coffey conclude that effects on birds, marine mammals and benthic communities adjacent to the dredging footprint and disposal areas will be less than minor. Sedimentation rates will be monitored and measures are proposed whereby if NTU thresholds are exceeded dredging will be modified or stalled such that thresholds are again met, ensuring that effects on ecologically significant areas are avoided. 20

22 I believe that baseline monitoring already carried out is robust and gives a good indication of the current state of health of the local benthic communities. I also believe the proposed mitigation measures and the proposed responses and monitoring, as outlined in the proposed conditions inclusive, address DoC s concerns. As for other DoC concerns such as avoiding the penguin breeding season and the orca stingray-hunting season, Mr Don and Dr Clement state in their ecological reports that they are of the opinion that the proposed programme does not pose any undue threat to penguins and/or marine mammals. I agree with their conclusions. (e) Whangarei Harbour Marine Reserve Advisory Committee has sought that the application be declined on the grounds of unknown and potential impacts on Whangarei Marine Reserve, particularly at Motukaroro. The Committee believes that there may be potential changes to turbidity and hydrology that may have a deleterious effect on the marine reserve. In my opinion the threshold turbidity values proposed by Refining NZ, and the recommended responses should those thresholds be exceeded, will afford sensitive areas near the dredging footprint, including Motukaroro, sufficient protection from harm such that I would expect there will be no observable adverse effects. (f) The Northland Scallop Enhancement Company Limited opposes the application. It voices a number of concerns, including that the proposal will adversely affect scallop beds, marine life and fisheries; and concern that excess dredge water will have adverse effects on scallops and related marine life. Once again, I believe the proposed mitigation measures and responses address these concerns and expect that overall effects on the scallop fishery and related marine life will be less than minor, with recovery of benthos to similar levels of diversity and abundance expected within 6 to 24 months. Further, Mr Richard Boyd, director of Boyd Fisheries Consultants Ltd, states in his evidence that there are no known commercial shellfish beds (that presently operate) within or immediately adjacent to either the dredging or disposal footprints. He also states that, in his opinion, following the completion of dredging and disposal, fishery habitats will recover from any temporary and localised impacts of the project. I agree with his conclusions. 21

23 (g) Fisheries Inshore New Zealand Limited opposed the granting of consent as it is concerned, among other things, that the proposal will have adverse effects on local inshore fisheries and the associated marine life and adverse effects on Three Mile Reef. It is expected that any effects on local inshore fisheries will be temporary and of very short duration. Overall effects are expected to be less than minor. It is also my opinion that Three Mile Reef is sufficiently removed from dredging and disposal activities that it will not be affected With respect to the proposed disposal sites, I once again refer to Mr Boyd s evidence in which he states that he believes any effects on the future potential use of the proposed disposal sites for commercial fishing will be negligible. (h) Barry Hubert Pyle has submitted in opposition to the granting of consent on the grounds that he has a number of concerns, including the possible introduction of undesirable exotic marine species and that echolocation and navigation by large marine mammal species would be affected. The introduction of invasive species is considered a real, but low risk. Proposed monitoring and agreement to work with MPI should such invasive species occur gives me confidence that this risk can be appropriately and robustly managed. Dr Clement, in her evidence, states that the area is not considered ecologically significant in terms of feeding, resting or breeding habitats for any marine mammal species and that underwater noise generated by the proposal is unlikely to affect marine mammals travelling through the area. Her overall assessment is the effects from the Proposal on marine mammals will be low to de minimis. (i) Patuharakeke Te Iwi Trust Board opposes the application. Among their concerns are that the pipi biomass on Mair Bank has declined in recent years, providing evidence of adverse effects. While this appears to be true there is no evidence (nor any suggestion) that the activities of Refining NZ have been a contributing factor in this decline. It is expected that the proposal will have a less than minor adverse effect on the pipi population. In my opinion it is likely that the proposed measures, such as enhancement of the Blacksmith s Creek estuary, will go some way toward reducing sediment input to the harbour and thus improving harbour water quality. As a consequence the health of benthic communities within Bream Bay, including the pipi beds, may ultimately be improved. 22

24 The Board also expresses concerns that the plume generated by dredging may have adverse effects and that disruption of benthic communities and inshore fisheries will be significant. Dr Coffey recognises that there will be some temporary loss of benthic communities and longer-term disruption of benthic productivity. However, he concludes that such effects will be localised and relatively short term, and I agree. Effects on inshore fisheries are expected to be less than minor. The proposed mitigation measures for Blacksmith s Creek and Estuary and monitoring, as outlined in the proposed Conditions will, I believe, more than compensate for the minor loss in benthic productivity. (j) Whanau of Henare Maki and Tuihau Elizabeth Pirihi have concerns that the material disposed of may create a foreign mound that may disrupt habitats and that there will be adverse effects on the scallop fishery. As Mr Reinen-Hamill explains in his evidence, there will indeed be a mound formed at the disposal site(s). However, such a mound will be made up of clean sediment dredged from just a few kilometres away, and will be comprised of similar sized particles. Thus, like will be deposited on like. As both Dr Coffey and I note in our evidence, we expect that recolonisation of the benthic substrate, by a similar faunal assemblage, will occur within 6 to 24 months at the disposal sites. (k) Mark Joseph Modrich opposes the application because he believes, among other things, that effects on fishing have not been adequately addressed. He also believes that insufficient consideration has been given to the duration of the works and the potential for the destruction of habitat. Dr Coffey, Mr Boyd and Mr Greenaway have, I believe, adequately considered likely effects on recreational and commercial fishing in the project area and concluded that effects will be less than minor. Dr Coffey has also, correctly in my opinion, concluded that habitat loss will be confined to a relatively small area and that will recovery to a similar state will be complete within 6 to 12 months for fine substrate and 6 to 24 months for some shell-hash areas. (l) The Ngatiwai Trust Board also believes that effects on fishing have not been adequately addressed and fear that the inshore fishery will be adversely affected. As stated in the previous paragraph Dr Coffey, Mr Boyd and Mr Greenaway have, I believe, adequately considered likely effects on fishing in the project area and concluded that effects will be less than minor. 23

25 (m) Adrian Ellis Tonks opposes the application for a number of reasons, including a belief that fine material disturbed by the dredging and disposal process will smother benthic communities. The suggestion is made that land based disposal would be preferable. It is also suggested that mitigation measures that reduce sedimentation elsewhere in the harbour should be explored. The threat posed by suspended sediments is well recognised. However, it should be pointed out that very fine sediment comprises only a very small percentage of the material that will be dredged. I believe that the threshold turbidity values proposed, and the recommended responses should those thresholds be exceeded, will afford sensitive areas near the dredging footprint sufficient protection from harm. The proposed measures centred around Blacksmith Creek will, I believe, go some way towards achieving the aim of reducing harbour sedimentation. 98. Overall, I have considered the submissions that relate to ecology/turbidity issues and consider that the Proposal design and recommended consent conditions appropriately address the issues raised. Further, nothing in the submissions causes me to change my opinions in relation to the Proposal, or my support for the opinions expressed by Drs Clement and Coffey, and Mr Don. RESPONSE TO THE SECTION 42A REPORT 99. I have read and considered the Section 42A report and annexes and provide the following response At paragraph 218 of the Report it is stated that water clarity at the harbour entrance is very good, with levels generally less than 1 NTU and even maxima well within the ANZECC guideline of 10 NTU. However, it must be pointed out that this conclusion is based on relatively few data points. Continuous monitoring carried out by Refining NZ at the Motukaroro Marine Reserve, opposite Marsden Point, in (for example) May-June 2017 has shown that, while surface water clarity is generally good, it is less clear than the stated generally less than 1 NTU would indicate. During the monitoring period by Refining NZ, the mean ambient NTU was 5.1, with maxima occasionally exceeding 100 NTU, especially in association with rain events However, assuming ambient levels, recorded by Refining NZ during the later half of 2017 are indeed representative, the thresholds proposed for environmental 24

26 management during dredging operations are considered conservative enough to ensure the protection of adjacent benthic communities I agree with Mr Mortimer at his paragraphs 278 and 279 regarding his assessment of recovery of benthic communities at disposal sites 1.2 and 3.2. i.e. that recovery back to, or close to, pre-existing conditions is expected While concern is expressed at paragraph 290 that the proposal may exacerbate or prolong the recent decline in shellfish biomass on Mair Bank, I agree with the author that such effects are more likely to result from changes to coastal processes than from effects of the proposal. The evidence of Dr Coffey, Dr Beamsley and Mr Reinen-Hamill is that Mair Bank will not be adversely affected by the proposal, and I agree Further, I agree that ecological effects on Calliope Bank are likely to be no more than minor Lastly, given that the habitat in the dredging and disposal areas is considered neither rare nor significant on a regional or national basis, I am in agreement with the Section 42A Report author at their paragraph 640. This states that it can be assumed, based on the investigations that have been done in and around the locality and the known sandy seabed within most of the bay (excluding Three Mile Reef), that the area affected is only a small part of a much larger habitat area within which fish can and do feed. Therefore, while there will be a localised adverse effect within the channel area during dredging campaigns, if the "ecological site" is taken to be the more or less contiguous area of seabed with the same or similar characteristics within Bream Bay then, at that level, the level of effect would not be adverse Lastly, Mr Mortimer seems to question (at his paragraphs 639 and 640) if the area to be dredged would qualify as being significant if it is assessed against Policy of the partially operative Regional Policy Statement for Northland. As I noted in paragraph 76, I have considered the dredged area (and indeed all of the ecological habitat/ecology that could be impacted by the Proposal) in light of Policy and conclude that the dredged area is not ecologically significant on either a regional or national basis, and the Proposal will not be in conflict with Policy I note that Dr Coffey confirms this in his evidence also. PROPOSED CONDITIONS 107. I have read the proposed Conditions and believe they are generally well reasoned and appropriate. I recognise that the Conditions are of a draft nature and are yet to be confirmed. Having reviewed the conditions I have made a number of 25