IN THE MATTER of the Resource Management Act 1991

Transcription

1 BEFORE A BOARD OF INQUIRY IN THE MATTER of the Resource Management Act 1991 AND IN THE MATTER of a Board of Inquiry appointed under section 149J of the Resource Management Act 1991 to consider an application for Notices of Requirement and Resource Consents made by the NZ Transport Agency, in relation to the Main South Road Four Laning (MSRFL) and Christchurch Southern Motorway Stage 2 (CSM2) Project STATEMENT OF EVIDENCE OF JEREMY WILLIAM TREVATHAN DATED 20 MAY INTRODUCTION 1.1 My name is Jeremy Trevathan. I am an Acoustic Engineer and Director of Acoustic Engineering Services Limited (AES), an acoustic engineering consultancy based in Christchurch. I hold the degrees of Bachelor of Engineering with Honours and Doctor of Philosophy in Mechanical Engineering (Acoustics) from the University of Canterbury. I am an Associate of the New Zealand

2 Planning Institute, and a Member of the Acoustical Society of New Zealand. 1.2 I have eight years experience in the field of acoustic engineering consultancy and have been involved with a number of environmental noise assessment projects throughout New Zealand. I have previously presented evidence at Council and Environment Court Hearings, and before Boards of Inquiry. I have acted on behalf of applicants, submitters and as a peer reviewer for Councils. 1.3 I have read and am familiar with the Code of Conduct for Expert Witnesses in the current Environment Court Practice Note. I agree to comply with this code of conduct in giving evidence to this hearing and have done so in preparing this written brief. The evidence I am giving is within my area of expertise, except where I state I am relying on the opinion or evidence of other witnesses. I have not omitted to consider material facts known to me that might alter or detract from the opinions expressed. I understand it is my duty to assist the Court impartially on relevant matters within my area of expertise and that I am not an advocate for the party which has engaged me. 2.0 BACKGROUND 2.1 On this occasion I have been engaged by J & S Shanks of 150 Trents Road, Christchurch, to provide acoustic engineering advice in relation to their submission regarding the MSRFL and CSM2 Project 2.2 My client operates Trent s Estate Vineyard, a function centre and wedding venue from 150 Trents Road. Outdoor wedding ceremonies are an integral part of the business and my client is particularly concerned about the impact of increased noise levels as a result of the CSM2 project. My client has also raised concerns about the increase in noise levels at their dwelling which is also located on the site. 2

3 2.3 I have reviewed the Assessment of Operational Noise Effects as prepared by Marshall Day Acoustics (MDA) and dated November 2012 as well as the statement of evidence of Mr Stuart Camp dated 18 April I have also reviewed the supplementary letters prepared by MDA dated 7 February and 5 March 2013 which respond to several queries from my Client and are appended as Appendix A to the Statement of Evidence of Mr Camp. 2.4 I note that my office has previously undertaken noise verification measurements on behalf of Opus International Consultants for Stage 1 of the Christchurch Motorway. We have not sought permission to use this data as part of this assessment. 3.0 AMBIENT NOISE LEVELS 3.1 MDA undertook noise monitoring using an unattended noise logger located at Trent s Vineyard over three consecutive days in October 2011 and conclude that an existing ambient 24 hour average noise level of 47 db L Aeq (24h) is representative of typical noise levels experienced at the site. 3.2 In response to our clients concerns that the measurement period did not reasonably characterize the ambient environment, we have undertaken additional noise monitoring at the site. 3.3 We installed an unattended noise logger at the MDA measurement position between Saturday the 20 th and Sunday 28 th of April and Saturday 11 th and Sunday 12 th of May Measurement periods which were outside the Meteorological window described in NZ6801:2008 Acoustics Measurement of Environmental Sound were disregarded. 3.4 As a result of this monitoring we have obtained measurement data for ambient levels over six days (being four weekdays and two weekend days) as presented in Appendix A of this evidence. The 3

4 24 hour average noise level was consistent over the measurement periods, with ambient noise levels for individual days of 42 to 44 db L Aeq (24h). 3.5 Mr Camp has confirmed in his evidence that MDA have used the quietest day as a basis for their noise assessment. I note that the quietest 24 hour average ambient noise level which we observed was 42 db L Aeq (24h). This level was measured on Tuesday the 23rd of April and is 5 db lower than the quietest day during the MDA assessment. 3.6 On the highest day the average ambient noise level at the site is 44 db L Aeq (24h) which is still 3 db lower than the ambient noise level presented by MDA. 3.7 I therefore conclude that the MDA monitoring results are not representative of the ambient noise environment at the Trent s Vineyard site and overstate typical ambient levels by some margin. 4.0 EXPECTED CHANGE IN NOISE LEVELS 4.1 In the original Assessment of Operational Noise Effects, MDA predicted that noise levels of less than 53 db L Aeq(24h) may be expected in outdoor function areas of the Trent s Estate site due to noise from the CMS2 project. 4.2 Specific noise levels have been presented in further correspondence between MDA and my client. In particular a 1 hour average noise level of 51 db L Aeq(1h) is predicted for the Wedding Venue site as a result of traffic noise between the hours of 4 and 6 pm. At the first floor of the dwelling a noise level of 53 db L Aeq(1h) is predicted during the peak traffic period between the hours of 7 and 9 am. This correspondence has been included as Appendix A in the Statement of Evidence of Mr Camp. 4

5 4.3 When considering the average 24 hour noise level as predicted by MDA, in conjunction with the average ambient environment at the site as previously discussed, I conclude that the ambient environment at the site will typically increase by between 9 db and 11 db at Trent s Estate as a result of the CSM2 project. 4.4 A noise level increase in the order of 10 db is typically described as a subjective doubling in loudness. I consider this to be a significant increase in the noise levels received at the site. 4.5 This is confirmed in Table 17 of the MDA Assessment of Operational Noise Effects in which MDA outline that a noise level change of between 9 and 11 decibels will result in a significant impact and a substantial RMA effect. A change of greater than 11 db is a severe impact. 5.0 EFFECTS ON OUTDOOR WEDDING CEREMONIES 5.1 As outlined in the evidence of Mr Camp, since commercial premises such as wedding venues are not specifically noted as noise sensitive receivers under NZ6806, section of the standard states that it does not apply to these locations. However I do not consider the fact that this standard doesn t apply to wedding venues to mean that the effects on this property should not be assessed. It appears that the authors of NZS6806 have limited the scope to the most-commonly encountered noise sensitive receivers. 5.2 Mr Camp has proposed a level of 55 db L Aeq(1hr) as an appropriate target for construction noise at outdoor wedding ceremonies. This is significantly lower than the construction noise limit outlined in NZS 6803 which is 75 db L Aeq for commercial premises and residential zones during relevant daytime periods. I consider that Mr Camp s position regarding construction noise reflects the fact that the wedding venue is a unique case. I agree. 5

6 Effects of elevated average traffic noise 5.3 While in general terms I consider that a noise limit of 55 db L Aeq(1hr) is an appropriate level for both construction and operational noise to protect against activity interference at outdoor wedding ceremonies for a greenfield site, in this case the predicted noise levels represent a significant increase over the existing ambient environment. While this will not prevent outdoor wedding ceremonies being undertaken, it will significantly change the character of the ambient acoustic environment. 5.4 Other than direct interference with communication, effects on outdoor weddings are difficult to quantify using traditional acoustic measures. Guests will be in the area for the purpose of undertaking a specific outdoor activity which involves particularly noise sensitive aspects. It is likely that they will have chosen the function venue with the perception that it embodies a certain set of values, such as rural character. 5.5 Several studies have been undertaken in order to investigate the response of people to noise in outdoor rural recreational environments 1. In such environments these studies conclude that the level of annoyance is not purely dependent on the absolute sound level. There are several factors which influence how noise levels are perceived, including socio-psychological aspects such as the appropriateness of the noise in the setting and the character of the noise. Particular weight is placed on whether the noise source is manmade or natural. 5.6 As an example of the reduction of the quality in the ambient environment which will be experienced at Trent s Estate, I expect that the distance in the outdoor venue area at which speech at 1 Kariel, H Factors Affecting Response to Noise in Outdoor Recreational Environments Kariel, H Noise in Rural Recreational Environments Chau, K; Lam, K and Marafa, L, Visitors response to extraneous noise in countryside recreation areas 6

7 typical conversational levels will be considered satisfactorily intelligible would reduce from 12.5 metres with the current ambient environment to 5.5 metres with a background noise contribution of 51 db L 2 Aeq(1hour). I understand that there are periods during a ceremony where speech at these levels is typical, such as when vows are read. 5.7 At raised voice levels, the distance at which speech would be considered to be satisfactorily intelligible would reduce by 13.5 metres with the CSM2 contribution. 5.8 I understand that the use of voice amplification for outdoor wedding ceremonies is based on the personal preference of the guests. Even at larger wedding ceremonies where guests may be located up to 8-10 metres from the speaker, guests may choose not to use voice amplification. With the significant increase in noise levels at the site, I expect that the use of voice amplification may be required in situations where it is not currently used. Effects of maximum noise levels 5.9 Both construction and operational noise may contain discrete noise events which have the potential to be intrusive, even when the average noise level is appropriately controlled In this particular situation, I expect it to be the construction phase of the project where such events have the greatest potential to disrupt wedding ceremonies. Such events are best quantified using the L max noise metric. This approach is consistent with the methodology adopted in NZS 6803:1999 Acoustics Construction Noise which provides limits in terms of average (L eq ) and maximum 2 U.S. Environmental Protection Agency Information on Levels of Environmental Noise Requisite to Protect Public Health and Welfare with an Adequate Margin of Safety, Appendix D Noise Interference with Human Activities and Resulting Overall Annoyance/Health effects 7

8 (L max ) limits Mr Camp has proposed a revision to draft condition DC.17 with the intent of limiting construction noise at Trent s Vineyard to 55 db L Aeq(1hr) within 50 metres of the wedding venue on Friday, Saturday and Sunday afternoons after 2 pm during the wedding season. I generally agree with this approach, however I also propose that draft condition DC.17 is modified to include a 70 db L Amax limit to account for impulsive noise events during construction With regard to noise generated by individual loud vehicles once the motorway is operational, I consider that it is not appropriate to compare maximum events in the existing ambient environment with the noise levels generated by maximum traffic events. In correspondence between the MDA office and my client, appended to Mr Camp s evidence as Appendix A, MDA has stated that noise from environmental events such as birdsong will be up to around 70 db L Amax. While I agree that there will be environmental events of this magnitude on occasion at the Trent s site, I consider that these events are significantly different in character and therefore the subjective response will be markedly different. However as described above, I consider that it is the marked increase in average traffic noise levels which has the greatest potential to effect wedding ceremonies. 6.0 NOISE MITIGATION 6.1 If a 3 metre high noise barrier were incorporated close to the motorway just south of the cut/batter area it would be expected to reduce the noise levels received at Trent s Estate by in the order of 5 db. 6.2 With this mitigation in place, noise levels as a result of the CSM2 proposal would represent an increase of only 4 to 6 db over the existing ambient environment. 8

9 6.3 While on quieter days this would still represent an appreciable increase over the current ambient environment, generally this mitigation would provide a meaningful benefit for Trent s Estate compared to the situation currently proposed. 6.4 I note that alongside the motorway is the most effective position for a noise barrier. A barrier of equivalent height constructed along the northern boundary of the Trent s site would not be as effective in mitigating noise to the wedding venue area. 6.5 If this barrier were constructed during the early stages of motorway construction it may also serve to mitigate noise from construction received at Trent s Estate, and as a result may allow the contractor to continue works on this part of the motorway, when otherwise they may not have been able to. 7.0 CONCLUSIONS 7.1 I consider that based on my own noise monitoring at Trent s Estate, MDA has overstated the existing ambient noise environment at the site by up to 5 db. 7.2 It follows that the predicted noise levels due to traffic noise from CSM2 will be in the order of 9 to 11 db higher than the current ambient environment. This is a significant increase in noise levels. 7.3 Any increase in noise levels as a result of the CSM2 proposal will have an increased effect on guests and operation of the wedding venue which is not well captured using traditional acoustics measures. An example of this effect is that the use of voice amplification for outdoor wedding ceremonies will be required in situations where it may not have been required previously. 7.4 The inclusion of a 3 metre high noise barrier alongside the motorway would provide a meaningful reduction in the noise levels 9

10 expected at Trent s Estate including noise from construction activities. Jeremy William Trevathan 20 May

11 70 Sound Pressure Level db LAeq15min Monday 22/04/13 Tuesday 23/04/13 Wednesday 24/04/13 Thursday 25/04/13 Saturday 11/05/13 Sunday 12/05/ Time (hours:mins)