Comments on Noise and Vibration Assessment
SLR Consulting was hired by Westconnex to conduct an assessment of the noise and vibration impacts of the Westconnex. Its report can be found in Chapter 10 of Volume 1A from 10.1 onwards continued at 10-3 -10-47 [here](10-3 -10-47) and also in Volume 2C, Appendix I.
Noise could have a long term impact on those who would live beside the proposed M4 East or in local streets and roads carrying extra traffic nearer tunnel exits and on ‘rat runs’. Construction noise from demolition, thousands of truck movements a day and rock crushers would impact on local communities and businesses. In some situations this could occur for several years. In others, the impact would be over shorter periods. Research has shown that noise does have negative effects on health. Vibration from construction including tunneling could cause cracked walls. Westconnex has already begun warning residents of this risk.
The SLR report does recommend noise mitigation for some buildings, although only up to the first story. It recommends noise walls and other strategies that would reduce the noise. Some buildings on Parramatta Rd that would under normal circumstances be offered noise protection would be left exposed so that the land between these buildings and the motorway can later be developed.
In the absence of that we asked an environmental scientist to review the material in Chapter 10 in the EIS . For personal reasons to do with her employment, we cannot publish the environmental scientist’s name.
It’s worrying that there are many gaps in the EIS and much is also left to future decision making during the final design phase. There are many issues here that need following up.
The EIS reports are presented in ways that even make it difficult for residents to see whether their neighbourhoods would be affected by excessive noise levels or not. While it’s expected that technical data can be hard to understand, the summary chapter should be presented in a more accessible way. This is just one of the reasons why residents want more time for the consultation period so that they could hire their own independent consultants. We can safely say that the EIS shows that hundreds of homes and thousands of residents would be affected by noise either during the 3 year long construction period or after the opening of the tunnel should it be allowed to proceed.
If you are worried about this issue and cannot understand the EIS. we suggest asking your local Council to arrange for it to be fully explained.
Given the uncertainty raised in a range of areas of the noise and vibration assessment and the number of potentially impacted properties and people within the project area, further work needs to be done to ensure the local community and other affected stakeholders are provided with a fully informed assessment. This must occur as part of the EIS consultation process where further comment can be sought from the community, and not simply resolved through the Submissions Report which does not allow any further input from the community.
Gaps in Westconnex EIS analysis.
Deficiencies in reporting of noise monitoring results
Table 10.2 does not provide information on what times of day, evening or night the noise levels presented for the attended noise monitoring was undertaken. If the purpose of the attended monitoring was to support the data gathered through unattended monitoring, then attended noise monitoring results for each of these time periods should be provided.
Construction noise management levels
Table 10.3 states out that the noise management levels (NMLs) for construction works during standard hours should be the rating background level (RBL) +10dBA and the rating background level +5dBA for out of hours works (based on the Interim Construction Noise Guideline (INCG), however not all of the NMLS for the project have been accurately calculated in Table 10.4 when compared to the measured INCG RBLs in Table 10.2.
INCG RBLs for monitoring location L23 are 53dBA (day-time), 52dBA (evening) and 46dBA (night-time) which should make the out of hours NMLs for this location 58dBA (day-time), 57dBA (evening) and 51dBA (night-time), however the night-time NML in this table is shown as being 54dBA
INCG RBLs for monitoring location L22 are 53dBA (day-time), 53dBA (evening) and 49dBA (night-time) which should make the out of hours NMLs for this location 58dBA (day-time), 58dBA (evening) and 54dBA (night-time), however the NMLs shown in this table are 66dBA (day-time), 62dBA (evening) and 47dBA (night-time)
There are other inaccuracies in the calculations given and this whole section needs to be reviewed and amended as necessary. This would then need to be compared against the data predicting exceedences of the NMLs to ensure that these are based on accurate NMLs.
Given the significant predicted noise impacts discussed in later sections of the EIS, this is absolutely critical to get right so that the local community can make an informed decision about what the potential noise impacts are likely to be.
Sleep disturbance during construction
Page 10-11 states that a sleep disturbance NML of 55dBA LAFmax (internal) and 65DBA LAFmax (external) has been adopted, however Table 10.4 provides varying sleep disturbance NMLs for each noise catchment area and does not specify whether the sleep disturbance NML is internal or external.
** Page 10-29 summarises that Tables 10.14 to 10.19 show that sleep disturbance criteria are predicted to be exceeded during all construction scenarios that are proposed at night and notes that the INCG only requires consideration of maximum noise levels when more than two consecutive nights are proposed. More detail on how potential sleep disturbance would be managed must be included in the EIS given the proposal to conduct such extensive out of hours works as identified throughout this section of the EIS.**
In s10.3.2 on page 10-15 there is discussion about the application of blast vibration criteria with a statement:
“For projects such as this, with a shorter duration of blasting of 12 months or less, a higher vibration criterion may be reasonable. For this project, the location of the blast moves along the alignment such that any one receiver is affected for only a short period of time.”
With no detail given about how long ‘a short period of time’ is, there is no way to determine whether it is appropriate that a higher vibration criterion be permitted, irrespective of whether or not the referenced standard was developed for mining operations rather than road tunnel construction. Given the range of sensitivities to vibration within any one community, it would be more appropriate to apply a conservation measure in the first instance.**
In s10.3.2 the control of damage from air blast is discussed and there is a statement that:
“Nominating appropriate criteria for heritage buildings generally require site inspections; this would be confirmed during detailed design.”
The SEARs state that the EIS must “include an environmental risk analysis to identify the potential environmental impacts associated with the infrastructure” and “where relevant…must include…measures to avoid, minimise and if necessary, offset the predicted impacts, including detailed contingency plans for managing any significant risks to the environment.”
If nominating appropriate criteria for the control of damage from air blast requires further site inspection then this should be conducted as part of the EIS process in order to meet the requirements of the SEARs as referenced above. Delaying this until detailed design, the completion of which would realistically occur some time after the commencement of construction should the project be approved, is not adequate given the potential impacts to the heritage and the concerns about this in the community.
Table 10-23 shows a total of 203 residential and light commercial buildings, 238 typical buildings, 11 heritage listed and 13 structurally unsound buildings are within safe working distances of highest vibration plant for cosmetic damage. 493 buildings are within the human response criteria for vibration. Additionally, three more properties are within the safe working distance for human response due to proposed tunneling activities.
This is a large number of buildings that are going to be placed at risk of cosmetic damage and an even more significant number of buildings within which people would be at risk of experiencing adverse effects from vibration. The number of buildings predicted to be impacted by vibration is worrying, particularly for the human response criteria as this impacts on the health and wellbeing of residents.
Page 10-35 refers to a detailed analysis of the potential vibration impacts needing to be undertaken for locations where the predicted and/or measured vibration levels are greater than the nominated screening levels, but no timeframe is supplied for this. Similarly, s10.4.5 discusses the need for further investigation into predicted noise and vibration levels after confirmation of the scope of blasting to determine whether or not the cosmetic damage and human comfort criteria would be met.
Given the significant numbers that are predicted to experience vibration impacts, both of these analyses should be undertaken as part of the EIS process so that the local community and potentially impacted residents can make a fully informed opinion on the proposed project.
The proposed management measures in this EIS are also not adequate to mitigate the potential vibration impacts on such large numbers of receivers as they do not discuss ways to reduce or eliminate vibration impacts or provision of respite. More rigor should be applied to determining the exact extent of potential impact and what would be done in a practical sense to ensure that people and buildings are not exposed to potentially damaging levels of vibration.
Demolition of buildings
Table 10-13 shows that in 13 NCAs exceedences of the NMLss are predicted to be up to or more than 25dBA during day-time works. Given the RBLs are 10dBA less than the NMLs, then this means that over half of the NCAs would experience noise levels of up to or more than 35dBA above the existing background level during demolition. The Transport for NSW Construction Noise Strategy referenced on page 10-5 of the EIS categorises this level of noise impact to be “highly intrusive” as it uses the rating background level as the starting point for determining exceedences.
What is proposed to mitigate noise impacts associated with demolition? As a minimum, highly affected receivers should be offered respite (accommodation elsewhere paid for during construction period.)
Work area establishment
Table 10-14 shows exceedences of up to or more than 25dBA above the NMLs are predicted for work areas establishment in 14 NCAs during standard daytime hours, with exceedences of more than 25dBA predicted for all but two sets of receivers during out-of-hours works. These exceedences are excessive and would have a significant impact on nearby receivers.
Table 10-16 shows that operation of construction facilities is predicted to significantly exceed NMLs during night-time operations, including exceedences of 50dBA or more in 4 NCAs and 11 NCAs that are predicted to exceed night-time NMLs by 30-50dBA. This represents a significantly intrusive impact to residents and night-time operations should not be considered reasonable for residents to have to endure in these locations.
The opening paragraph on road construction states that new road works would be undertaken within the construction footprint, however out of hours works would be likely to minimise impacts to traffic and reduce safety risks for workers. If the works are being conducted entirely within the construction footprint, then why would there be potential impacts to traffic and workers safety? Does this actually mean that new road works would be undertaken within areas that are currently in use for road operations?
Table 10-17 shows that exceedences of over 25dBA above the NMLs are predicted for the majority of NCAs for all time periods during road construction works. Given the significance of this level of exceedence, more detail should be provided about exactly how much over 25dBA predicted exceedences are for each of these time periods. The information presented in the table indicates that the majority of the NCAs would experience high noise impacts (at the higher end of “moderately intrusive” as defined by the TfNSW CNS) for the duration of road works. This represents a significant burden on the local community, particularly during out of hours works when sleep disturbance is likely.
Tunneling is proposed to be carried out 24 hours a day, seven days a week and some above ground tunnel construction ancillary facilities would also be in use 24 hours a day, seven days a week to support tunneling works. Page 10-28 states that:
“NMLs for residential properties located close to the tunnel construction ancillary facilities are predicted to be exceeded by more than 25dBA during the night-time periods. These exceedences would be restricted to residential properties directly adjacent to tunneling sites. Where exceedences are expected, properties would be considered for construction mitigation.”
Even with the proposed installation of acoustic hoarding and the assumption that this would afford a 10dBA reduction in noise levels, there would still be residential receivers who would experience exceedences of more than 25dBA above the NML, as shown in Table 40 of Appendix I.
It is unacceptable to expect residents to be subjected to such potentially high noise levels 24 hours a day, seven days a week as this provides no respite from noise, light, dust and traffic impacts. It is also noted that the statement above gives no certainty about whether or not mitigation would actually be implemented, merely considered.
Highly noise affected residential receivers
Table 10.21 shows more highly noise affected receivers after acoustic hoarding is installed in NCA 13 and NCA 21– why is this? Installation of acoustic hoarding should reduce the numbers of impacted receivers, not increase.
Section 10.4.2 indicates that there are a number of locations within 40 metres of tunneling works where the criteria for ground-borne noise would be exceeded in both the evening and night-time. While it is mentioned that the duration of these impacts would be a relatively short period of time at each location, there is no discussion on what mitigation would be implemented to reduce the impacts on the directly impacted residents. Given exceedences are predicted for the time periods that people are more likely to be at home and trying to sleep, this is not adequate.
Construction traffic noise
Given that spoil removal and concrete delivery are proposed during the night in s10.4.3, with potential impacts at Short Street East, the fact that detailed assessment of potential maximum night-time noise events on local roads has not yet been undertaken is inadequate and does not allow affected residents in this area to be able to determine what the potential impacts on them are.
The reference to sleep disturbance in s10.4.3 is disingenuous as it only refers to light vehicles whereas sleep disturbance is more likely to be caused by heavier vehicles that would be undertaking night-time spoil removal and concrete delivery.
Operational noise and vibration impacts from ventilation facilities
Table 10-28 and the text below it shows that modelling has not been undertaken to predict potential operational impacts from the three proposed ventilation facilities. This does not allow potentially affected receivers to be able to make an informed opinion on what the impacts may be.
Is it known whether or not the proposed maximum allowable sound power level for these facilities is achievable? What is the process if it is not?
Operational noise impacts and mitigation
Page 10-37 states that:
“…the project is predicted to result in an overall reduction in the number of receivers where exceedences of the noise criteria are experienced….This reduction is a result of reductions in the numbers of vehicles using some surface roads…
Large reductions in noise levels (up to 8dBA) have been identified…due to a reduction in the number of vehicles using the surface M4…”
A reduction of up to 8dBA while noticeable, would not necessarily be clearly audible, and as such is better described as a moderate reduction rather than large. The predicted “increases in noise levels (up to 16dBA)” are however more accurately described as large when they are at the upper end of being clearly audible.
The predicted reductions are based on the traffic modelling for the project undertaken on behalf of a proponent with a vested interest in undertaking road projects and as has been seen in a number of other large road infrastructure projects in Sydney in recent years, inaccuracies in traffic modelling can have disastrous impacts on the viability of a project on completion and on the community who are left shouldering the burden of such infrastructure in their local environment. This, combined with the fact that predicted increases in operational noise impacts are significantly higher than the predicted reductions in other areas, does not provide ample evidence that the project is justified.
Seven new or increased height noise barriers are proposed as part of the project. Some of the new noise walls are proposed to be 5m or 6m high which has the potential to significantly impact on the amenity (visual impact and overshadowing) of residential properties that are immediately adjacent to the proposed noise walls. Even with construction of these noise walls and the installation of low noise pavement, a large number of receivers (310) would still need consideration of additional mitigation. At-property treatment for noise mitigation, while being able to help achieve operational noise goals, also means that people are restricted in being able to open their windows without experiencing noise impacts, so can have a significant impact on the amenity of their property. The number of receivers that may need further at-property treatment is very high and further work should be done on the design and/or alignment of the proposal to reduce this number to a more acceptable level.
Table 10.24 shows number of receivers still affected operational traffic noise with mitigation installed in a number of scenarios. As this table uses different terminology to that of the scenarios at the beginning of the noise and vibration assessment on page 10-6 of the EIS, a direct comparison is made more difficult and it can only be assumed that the four scenarios presented in Table 10.26 are meant to mirror those given on page 10-6. There is also confusion caused by the explanatory text above this table that refers to data about numbers of affected receivers in scenarios without mitigation that is not shown in the table. The EIS should clearly communicate what the predicted operational impacts are likely to be and it does not do that.
The assessment of maximum noise levels discussed on page 10-42 indicates that there are a number of locations where the maximum noise level would increase but that not all of these potentially affected receivers would be eligible for property treatments. As some of these receivers would also be in line of sight to elevated vehicle exhausts, this is not an adequate response to a potential increase in maximum noise levels and impacts to health, wellbeing, visual amenity and air quality.
Environmental management measures
A number of environmental management measures for noise and vibration are proposed in the EIS. Of particular concern are the following:
“Permanent noise barriers will be scheduled for completion as early as possible in order to minimise construction noise”
“Property treatments identified for the operational phase of the project will be considered for installation before or early in the construction period, where they would improve noise levels”
Given the number of areas where the EIS delays the detailed assessment of noise and vibration impacts, presumably until after project determination, it is most likely that construction would commence well before information is available to base noise barrier design on, let alone construct them. Detailed noise and vibration assessment should be included in the EIS rather than deferred to after the project has been assessed and determined so that a more accurate picture of what is proposed is presented to the community for consideration and so that management measures such as these can be realistically implemented.
“Night works will be programmed to minimise the number of consecutive nights that work affects the same receivers, where feasible. This would not apply to civil and tunnel sites.”
The proposal to undertaken tunneling activities 24 hours a day, seven days a week is inconsistent with this management measure, particularly given the need for supporting tunneling facilities to be utilized at the same time. The exemption of civil and tunnel sites covers a significant portion of the project works, making this exemption almost universal.
Out of hours/night works should only be undertaken when it can be demonstrated that no other options are safe or the impacts to the surrounding receivers are absent or minimal. This is not the case being presented in this EIS and therefore more stringent limits on out of hours works should be applied, rather than more lenient as being proposed here.
“When working adjacent to schools, particularly noisy activities will be scheduled outside normal school hours, where practicable.”
While this proposed management measure is positive for schools, it also has the potential to increase the need for out of hours works and therefore must be considered in conjunction with other proposed management measures that relate to out of hours works. Given there are areas within the project’s influence that may be subjected to prolonged and/or noise out of hours works, a balance needs to be struck between impacts to schools and impacts to residential receivers.
“Respite periods (eg one hour respite for every three hours of continuous construction activity) will be scheduled for high noise impact works where appropriate”
The EIS does not state that respite periods will be used for properties impacted by 24 hour, seven day a week tunneling activities, however these are likely to be the most highly impacted due to predicted noise levels and duration of works.
“As far as practicable, construction vehicle movements along local roads at night will be restricted to light vehicles only, subject to further investigation of potential night-time maximum noise levels during detailed design.”
“Spoil removal will be undertaken during the day as far as practicable”
These measures are inconsistent with information discussed above, and NV28 below, which states that spoil removal and concrete delivery will occur at night. Spoil removal and concrete delivery will be undertaken with heavy vehicles so statements about restricting night-time movements to light vehicles is
“As far as practicable, heavy vehicle movements outside of standard construction hours associated with tunnel support works (spoil removal, concrete delivery and other heavy vehicle movements) will be limited to access and egress directly to and road network”
This needs further discussion on the numbers and location of potentially affected receivers within the EIS itself rather than this imprecise management measures.
“The safe working distances will be complied with where feasible and reasonable. This will include the consideration of smaller equipment when working close to existing structures.”
As outlined above, it is already known that there is a large number of buildings that would fall within the safe working distances, making the commitment to comply where feasible and reasonable meaningless in these areas. Smaller equipment should be specified, not just considered.
“If vibration intensive works are required within the safe working distances, vibration monitoring or attended vibration trials will be undertaken at the outset of these works to ensure that levels are within the relevant criteria.”
This management measure gives no assurance that vibration intensive works would not be carried out within safe working distances. Vibration monitoring once vibration intensive works have commenced is not appropriate given this in itself could cause damage and/or human discomfort.
“Once plant items within the ventilation building are confirmed during detailed design, impacts will be assessed with consideration of the INP modifying factors. Where modifying factors are found to be applicable they will be added to the assessment, and compliance with the INP criteria checked at all receivers.”
This management measure is specified as to be undertaken during pre-construction, however given it references detailed design, there is more likelihood that it would occur well after construction has commenced. As discussed above, there should be a specified process for how to manage non-compliances with the criteria prior to commencement of operation.