The Scoping Opinion has been taken fully into account in the preparation of this Chapter, as set out in Table 20.1 below.

Transcription

1 20 NOISE AND VIBRATION 20.1 Introduction This Chapter provides an assessment of the potential impacts to human receptors caused by noise and vibration during construction, operation, dismantling and restoration and, if required, removal and reinstatement of the jetty development. Mitigation measures are proposed to address any potential adverse impacts that are identified to be of significance Predicted noise levels at rural public amenity locations are considered to be representative of ecological receptor locations. Discussion of the potential noise and vibration impacts to marine and terrestrial ecology is provided in Chapters 10 and 11. a) Scope of Assessment Scoping Environmental scoping has been carried out by EDF Energy and is presented in the Hinkley Point C Preliminary Works Development Temporary Jetty Environmental Scoping Report (Ref 20.1). The scoping report was presented to the MMO, which provided a formal Scoping Opinion in response (Ref. 20.2) (Appendix 5-1, Volume 4) The Scoping Opinion has been taken fully into account in the preparation of this Chapter, as set out in Table 20.1 below. Table 20.1 Scoping Opinion Noise and Vibration Issues Page of Scoping Opinion Issue Response Page 45 Sensitive receptors Assessed receptors are identified in Section 20.3 e). Page 45 Ecological receptors Discussion regarding the potential impacts to internationally designated ecological sites is included in Chapters 10 and 11. Page 45 Decommissioning An assessment of potential noise and vibration impacts during removal and reinstatement works (should the Hinkley Point C Project not be granted planning consent) is provided in Section An assessment of potential noise and vibration impacts during dismantling and restoration is provided in Section Page 45 Operational vibration impacts to residential receptors A qualitative assessment of operational vibration impacts is provided in Section Page 46 Road traffic impacts An assessment of potential road traffic noise and vibration impacts is provided in Section Hinkley Point C Preliminary Works 20-1 Environmental Statement

2 Page of Scoping Opinion Issue Response Page 46 Effects on biodiversity Discussion regarding the potential impacts to ecological receptors is included in Chapters 10 and 11. Page 46 Page 72 Construction vibration impacts along site access routes Impacts to marine ecological receptors A semi-qualitative assessment of road traffic vibration is provided in Section Discussion regarding the potential impacts to marine ecological receptors is included in Chapter 10. Page 72 Agreed noise limits Detailed derivation of proposed noise limits has been provided to West Somerset and Sedgemoor District Council (see Section 20.1 a)) In general, responses requested that consideration of particular potential impacts, such as road traffic noise and vibration be included in the ES (see Section 20.5). Consultation In undertaking this assessment, consultations have been undertaken with the Environmental Health Officer (EHO) of West Somerset Council. A scoping consultation meeting was held with West Somerset Council on 9 December During this meeting the specific requirements for the assessment of noise impacts were discussed. The meeting achieved agreement regarding the choice of noise sensitive reference positions to be used for determining noise impacts at residential locations closest to the application site It was also agreed that due to the significant separation distances between the proposed development and the nearest residential receptors (greater than 1.2km from the proposed aggregates storage area and 1.5km from the jetty), vibration due to construction activities is unlikely to be significant. It was therefore agreed that a baseline vibration assessment was not required, although a baseline vibration survey was undertaken at a single residential location in Shurton, before, during and after trial blasting tests were performed on site. This survey was undertaken on a precautionary basis; in the unlikely event that blasting is required (in the rock extraction area only). The results of the survey are presented in the survey report (15011/TR/00155 Blasting Test Noise and Vibration Monitoring Factual Report, AMEC, 2010) (Ref 20.3) (Volume 4, Section 20, Part B). It should be noted that annoyance due to vibration is not related to a comparison of pre and post-development vibration levels, rather an assessment of future predicted levels, if applicable, against absolute thresholds values. Baseline vibration levels are not therefore usually necessary to assess the likelihood of vibration damage or annoyance from any new vibration sources Advice and direction regarding the operational noise assessment was provided by WSC, and has been taken into account within this assessment. This included the preference for impacts of plant noise during the operational phase to be assessed in accordance Hinkley Point C Preliminary Works 20-2 Environmental Statement

3 with BS 4142:1997, with a target criterion of 5dB above the prevailing background not to be exceeded A second consultation meeting was held with West Somerset Council (represented by Arup consultants) on 1 October At this meeting, the progress of the impact assessment was described, along with presentation of a summary of the results of the baseline noise monitoring survey. The noise limits for the jetty development, as outlined in Table 20.1, were presented to the consultees Following the second consultation meeting, West Somerset Council requested further clarification on the derivation of the proposed noise threshold values (24 February 2010). Further detail on this was provided on 19 March Assessment Content The assessment of noise and vibration impacts arising from the jetty development has been undertaken for the study area, defined in Section 20.3, and uses the best practice and standard methodologies described in Section The baseline noise conditions described in Section 20.4 are based on a survey of existing noise levels undertaken between 27 April and 7 May The survey methodology and the identification of appropriate monitoring locations were agreed with West Somerset Council prior to it being undertaken. The baseline noise survey was undertaken to establish the existing acoustic climate at the nearest noise sensitive receptors. Full details of the survey are provided in the Noise Monitoring Factual Report (Ref 20.4) (Volume 4, Section 20, Part B) along with a complete set of monitoring data Potential noise and vibration impacts on human receptors are assessed in Section The assessment considers noise and vibration impacts at residential dwellings, as well as noise impacts to users of public footpaths and visitors to other local amenities such as Pixies Mound. Appropriate mitigation measures aimed at reducing the impact of the proposed jetty development are identified in Section The residual impacts following implementation of the mitigation measures are presented in Section A summary of the impact assessments in a tabulated form is also provided in Section Potential cumulative effects of the jetty development in conjunction with the site preparation works, the Hinkley Point C Project and other relevant plans and projects are provided in Chapter 25. b) Objectives of Assessment The objectives of the noise and vibration assessment were to: identify all potentially sensitive receptor locations that may potentially be affected by the jetty development; characterise the baseline acoustic climate at representative locations for identified noise sensitive receptors; assess the noise and vibration impacts on neighbouring dwellings; assess the noise impacts on users of nearby public footpaths and other local amenities, such as Pixies Mound; recommend mitigation measures, if considered necessary, to reduce the noise and vibration impacts on neighbouring dwellings; Hinkley Point C Preliminary Works 20-3 Environmental Statement

4 assess the residual noise and vibration impacts on neighbouring dwellings; and assess the residual noise impacts on users of nearby public footpaths and other local amenity (Pixies Mound) This assessment has considered the potential nuisance impacts of noise and vibration to human receptors only. Jetty construction and operational noise magnitudes have been included for receptor locations that are representative of marine ecology and ornithology; in particular, wintering birds using the intertidal zone. The potential impacts of predicted noise generation to both marine and terrestrial ecology are addressed in Chapters 10 and 11 respectively An introduction to the principles of noise and vibration is provided in Appendix 20-1, Volume Criteria against which predicted noise and vibration levels are assessed have been derived from recognised national and international guidance. The relevant guidance documents are referenced throughout the assessment and are included in the references listed in Section Legislation, Policy and Guidance a) International Legislation and Policy The scope of works is not affected by international legislation, including that arising from the European Union (however, see Section 20.3 a) below with respect to guidance). b) National Policy Planning Policy Guidance PPG 24 Planning and Noise PPG 24 (Ref 20.5) was published by the Department of the Environment in Paragraph 1 states that it was issued to: provide advice on how the planning system can be used to minimise the adverse impact of noise without placing unreasonable restrictions on development or adding unduly to the costs and administrative burdens of business It outlines some of the main considerations which local planning authorities should take into account in drawing up development plan policies and when determining planning applications for development which will either generate noise or be exposed to existing noise sources For new developments that will introduce noise into an area, PPG 24 confirms, in Annex 3, that it is appropriate to use previously established assessment methodologies (i.e. when assessing Noise from construction sites (Annex 3, paragraph 21)). The appropriate assessment methodologies are discussed in Section c) Regional and Local Policy On 6 July 2010 the Secretary of State for Communities and Local Government revoked all Regional Strategies with immediate effect under section 79(6) of the Local Democracy, Economic Development and Construction Act This includes Regional Planning Guidance for the South West (RPG10). Hinkley Point C Preliminary Works 20-4 Environmental Statement

5 Therefore, Regional Strategies no longer form part of the development plan for the purposes of section 38(6) of the Planning and Compulsory Purchase Act EDF Energy will have regard to development plan documents, saved policies and any old style plans that have not lapsed, as well as national policy where relevant Local policies relating to the control and management of noise, including pollution control and nuisance, have been identified below. Whilst Local Plans (LPs) are due to be superseded by Local Development Frameworks (LDFs), West Somerset Council is yet to publish and / or formally adopt its LDF. In April 2009, West Somerset Council published its Local Development Scheme (LDS); a document to help to steer production of their LDF. This document includes a list of policies saved from the West Somerset District Local Plan by the Secretary of State (Ref 20.6). These saved policies in relation to noise and vibration are identified below. West Somerset District Local Plan Policy PC/2: Proposals for developments involving potential noise nuisance to existing occupiers of land or buildings will only be permitted when measures to minimise the impact of noise likely to be generated are incorporated as part of the development Methodology a) Introduction The baseline noise survey and the noise and vibration impact assessments detailed in this Chapter have been conducted in accordance with all relevant best practice and standard methodologies. Generic international guidance is provided by the World Health Organisation (WHO), whilst methodologies specific to construction noise assessment are described in detail below. World Health Organisation Guidelines for Community Noise (1999) (Ref 20.7) This document provides health-based guidance on suitable noise levels intended to avoid or minimise community annoyance. The guidance provides guideline noise levels for both indoor and outdoor areas. Of significance to this assessment the guidance states: During the daytime, few people are seriously annoyed by activities with L Aeq levels below 55dB; or moderately annoyed with L Aeq levels below 50dB Table 4.1 of the WHO guidelines recommends environmental daytime and evening limits of 55dB L Aeq or less over the 16-hour daytime period ( ) to avoid minimal serious annoyance, and 50dB L Aeq,16hr to avoid minimal moderate annoyance However, the WHO recommendations represent noise levels at which it is possible to start detecting effects in humans and below which effects can be assumed to be negligible. Consequently, compliance with the WHO Guidelines for Community Noise criteria can be interpreted as being a conservative approach, as exceedance of the recommended noise levels is not necessarily indicative of significant adverse effects. Hinkley Point C Preliminary Works 20-5 Environmental Statement

6 b) Construction Construction Equipment Noise Noise emissions from the proposed jetty construction are assessed differently to noise from permanent installations, as it is recognised that the former are an inevitable byproduct of required works and their effects are temporary. They are controlled by guidelines and are subject to Local Authority control. Advice is contained within British Standard BS 5228:2009 Noise and vibration control on construction and open sites - Part 1 Noise (Ref 20.8). This document contains a database of the noise emissions from individual items of equipment and activities to predict the noise from demolition and construction methods to identified receptors. Guidance is given on the effects of different types of ground, barrier attenuation and how to assess the impact of fixed and mobile plant. Predictions of noise propagation in accordance with BS were undertaken using CadnaA proprietary modelling software. A full description of the inputs and assumptions used for this exercise is presented in Appendix 20-2, Volume Whilst not mandatory, Annex E of BS provides advice to assist the development of noise assessment criteria based on previous published guidance and methodologies adopted successfully for other planning applications In assessing the requirement for noise limits, or operating period controls relating to construction, Government Agencies and Local Authorities generally give consideration to the following aspects of the planned works, all of which have a bearing on the significance of the impact: duration of the planned activities (weeks, months, years); whether activities are planned for the night-time period; proximity of the development to residential areas; and predicted source-term noise levels and noise impacts at residential areas The proposed criteria for works on the application site (including temporary construction areas) offer tighter control over noise emissions than recommended in BS :2009 Annex E. This is in recognition of the proposed duration of the construction works. Recommended criteria for construction works are typically referenced to longer time periods (i.e. 12-hour daytime, 4-hour evening or 8-hour night), which allow for more intensive, and more noisy work over shorter periods if the working schedule is wellmanaged. The shorter reference period of 1 hour for all periods as proposed would provide better control on the construction noise emissions throughout the construction. This takes account of the recommendation, in BS :2009 Annex E, for a 1-hour reference period to be adopted for long-term earthworks. This is despite the duration of the proposed earthworks associated with the jetty development being scheduled to take less than six months to complete The proposed noise emission limits for construction activities are presented in Table 20.2 below. EDF Energy is proposing that there would be no onshore earthworks and construction activities during the evenings or night-time periods, on Saturday afternoons or on public holidays (see Chapter 6); however, offshore jetty construction activities could occur during these times since some of the construction works would have to take account of the tides. Hinkley Point C Preliminary Works 20-6 Environmental Statement

7 Table 20.2 Proposed Noise Emission Limits for Construction Assessment Period Construction Noise Threshold (free-field)* Day of Week Time of Day db LAeq,1hour Monday Friday # # 45 Saturday # # 45 Sunday and Bank Holidays # # 45 Notes: db re: 20 µpa, * Measured at a noise sensitive receptor location (free-field), # Offshore construction work only. Where L Aeq = the equivalent continuous A-weighted sound pressure level, being the single number that represents the total sound energy measured over that period. Noise levels may be permitted up to 75dB L Aeq,1hour for specific works of short duration (onshore works only) where best practicable means have been demonstrated to West Somerset Council and noise sensitive premises have been informed at least 48 hours in advance Based on these values, the noise magnitude scale for use in the prediction of potential impacts is presented in Table Construction Traffic Noise The Design Manual for Roads and Bridges (DMRB) Volume 11 Section 3 Part 7 (HA 213/08) Noise and Vibration (2008) (Ref 20.9) provides a method of evaluating both the immediate and long-term impact of changes in the 18-hour traffic flow ( ) in terms of future impacts on people and, principally, occupiers of residential property DMRB requires that an assessment is undertaken where an increase in a road traffic flow of 25% or greater is predicted (equivalent to an increase or decrease in road traffic noise of approximately 1dB), implying that road traffic flow increases of up to 25% offer no significant impacts in environmental noise terms Assuming the traffic flow characteristics (notably speed and HGV composition) remain constant, a road traffic flow increase or reduction of 100% would equate to a 3dB change. In this regard, the Department of Transport Transport Analysis Guidance (2007 update) (Ref 20.10) states: For freely flowing traffic, a difference of about 3dB in noise level is required before there is a statistically significant change in the average assessment of nuisance. The assessment of nuisance however could still be affected even if there is only a 1dB Hinkley Point C Preliminary Works 20-7 Environmental Statement

8 change in the noise level if the change is associated with changes in the view of traffic, or if the change occurs suddenly. Table 20.3 Noise Magnitude Scale for Construction Assessment Period Construction Noise Magnitude db LAeq,1hour (free-field) Day of Week Time of Day Very Low Low Medium High < >70 Monday Friday # < > # < > < >70 Saturday # < > # < >50 Sunday and Bank Holidays # < > # < >50 Note: db re: 20µPa, # Offshore construction work only In order to assess the level of community disturbance from potential changes in local road traffic characteristics during the construction works, an assessment was undertaken based on the principles of the DMRB (Ref 20.9) guidance The change in basic noise level (BNL), calculated according to the methods given in Calculation of Road Traffic Noise (CRTN) (Ref 20.11), for each road section affected, has been used to assess the potential impacts. The definitions of noise impact magnitude in Table 20.4 have, therefore, been adopted (the change can be an increase or decrease of noise). Vibration during Construction Guidance on the assessment of the potential vibration impacts associated with construction activities is provided within British Standard BS 5228: 2009 Noise and vibration control on construction and open sites - Part 2 Vibration (Ref 20.12). This document refers to measurement and assessment guidance provided in BS 6472 Guide to evaluation of human exposure to vibration in buildings - Part 1: 2008 Vibration sources other than blasting (Ref 20.13) and BS 7385 Evaluation and measurement for vibration in buildings - Part 1: 1990 Guide for measurement of vibrations and evaluation of their effects on buildings (Ref 20.14) and, Part 2: 1993 Guide to damage levels from ground borne vibration (Ref 20.15) For the type of development proposed, plant such as bulldozers, excavators and heavy goods vehicles (HGVs) are likely to be the most significant sources of low frequency Hinkley Point C Preliminary Works 20-8 Environmental Statement

9 noise with the potential to cause resonance in nearby buildings, which is often perceived as vibration by occupants. Table 20.4 Guidelines for the Assessment of Magnitude for 18-hour Traffic Noise Magnitude High Medium Low Guidelines Considerable increase in the perceived noise levels typified as a difference of more than 5dB LA10,T from the existing ambient level. Noticeable change in the perceived noise levels, typified as a difference of 3 to 4.9dB LA10,T from the existing ambient level. Perceptible change in the perceived noise levels, typified as a difference of 1 to 2.9dB LA10,T from the existing ambient level. Very low Generally imperceptible change in the perceived noise levels typified as a difference of 0.1 to 0.9dB LA10,T from the existing ambient level In the marine environment, operations such as dredging and, in particular, piling have the potential to generate vibration of the seabed, underlying geology and the water Construction works such as those associated with the jetty development may cause sudden but intermittent vibration. In such events, it is necessary to be able to quickly compare levels against criteria to give an immediate evaluation of the likelihood of a problem without recourse to complex post-processing of results. Under these conditions, assessment criteria based on Peak Particle Velocities (PPV) are most appropriate Based on Table B.1 of BS (Ref 20.12), the proposed PPV significance criteria for typical construction activities (excluding blasting), measured at a sensitive receptor location, are presented in Table Although it is unlikely to be necessary during the jetty development, blasting of the bedrock may be required within the rock extraction area to source engineering fill material for levelling the aggregates handling platform. An assessment was therefore undertaken to determine the potential vibration impacts of blasting events should this process be required Assessment of the potential impacts of blasting has been undertaken in accordance with British Standard BS 6472 Guide to evaluation of human exposure to vibration in buildings - Part 2: 2008 Blast-induced vibration (Ref 20.16). This document provides a methodology for the prediction of the likely vibration magnitude based on the Maximum Instantaneous Charge (MIC) in kg, and the slant distance from the blast to the receptor in metres. In order to ensure that there are no adverse effects on both existing buildings and fresh concrete, a vibration monitoring scheme would be put in place during this phase of works. Hinkley Point C Preliminary Works 20-9 Environmental Statement

10 Table 20.5 Vibration Magnitude Assessment Criteria Applicable to Residual Receptors (Excluding Blasting) Magnitude Vibration Level (mm/s PPV) Effect High 10 Vibration is likely to be intolerable for any more than a very brief exposure to this level. Medium 1.0 It is likely that vibration of this level in residential environments will cause complaint, but can be tolerated if prior warning and explanation has been given to residents. Low 0.3 Vibration might be just perceptible in residential environments. Very Low 0.14 Vibration might be just perceptible in the most sensitive situations for most vibration frequencies associated with earthworks. At lower frequencies, people are less sensitive to vibration Based on Table 1 of BS (Ref 20.16), the proposed PPV significance criteria for blasting operations, measured at a residential receptor location, are presented in Table Table 20.6 Vibration Magnitude Assessment Criteria Applicable to Residential Receptors (Blasting Operations) Magnitude High Medium Low Very Low Guidelines Generation of PPV in excess of 24mm/s Generation of PPV in the range of >10 to <24mm/s Generation of PPV in the range of >6 to <10mm/s Generation of PPV below 6mm/s The above assumes that blasting and ripping of bedrock would only be undertaken during daytime hours (08:00 to 18:00 Mon to Fri, 08:00 to 13:00 Sat), and that that there would be no more than three blast events per day. c) Operation Operational Noise British Standard BS 4142:1997 (Ref 20.17) details a method of rating the likelihood of complaints about increases in the background noise level L A90 at noise-sensitive receptors affected by noise from existing or proposed fixed developments, such as the aggregates conveyor systems which would be used in the operation of the jetty In Section 9 of BS 4142:1997 Assessment Method it is stated that an increase above the existing background noise level L A90 of up to 5dB due to the rating noise level from Hinkley Point C Preliminary Works Environmental Statement

11 fixed plant at a new development is of 'marginal significance'. A limit of a 5dB increase from new, fixed plant noise sources was therefore recommended by WSC for use in this study Based on this, the proposed significance criteria for mechanical plant associated with the jetty development once fully operational, are presented in Table Table 20.7 Operational Plant Noise Magnitude Assessment Criteria Magnitude High Medium Low Very low Guidelines Specific noise level from operating mechanical plant more than 10dB above the existing LA90,T background noise level. Specific noise level from operating mechanical plant between 5 and 10dB above the existing LA90,T background noise level. Specific noise level from operating mechanical plant between 0.1 and 5dB above the existing LA90,T background noise level. Specific noise level from operating mechanical plant below the existing LA90,T background noise level. d) Study Area The geographical extent of the area under consideration is illustrated in Figure 20-1, Volume 3. The purpose of the assessment is to determine the worst-case impacts. Therefore, given the open nature of the surrounding land, it is reasonable to assume that the closest receptor locations to proposed works are those likely to experience the greatest noise and vibration impacts During the baseline assessment, ambient noise measurements were undertaken at locations that represented groups of residential receptors in Shurton. The nearest residential receptor (Knighton Farm) is approximately 1.2km south of the proposed aggregates storage area, and 1.55km south of the proposed jetty In addition, baseline noise measurements were undertaken at locations that were representative of public footpaths, both to the north of Shurton and on the coastal footpath at the northern boundary of the proposed aggregates handling facility. e) Definition of the Baseline Environment Noise Sensitive Receptors A noise sensitive receptor is identified as a location where significant changes in environmental noise levels have the potential to cause either detrimental or beneficial impacts. Recognised effects typically include impact on the amenity of an area, potential disturbance to sleep, effects on conversation or entertainment; degradation of an educational environment; or, interruption of a religious ceremony Noise sensitive receptors in the vicinity of the proposed development have principally been selected according to the likelihood of the impacts to occur, and also to represent a group of locations, on a worst-case basis, where similar impacts may occur. The Hinkley Point C Preliminary Works Environmental Statement

12 location of each baseline noise monitoring points, relative to the proposed jetty, are identified in Figure 20-1, Volume Receptor locations are free-field (i.e. greater than 3.5m from any reflecting surface other than the ground) at the three residential and four public amenity receptor locations. These positions are defined in Table 20.8 below, and shown in Figure 20-2, Volume 3. Table 20.8 Assessed Noise Sensitive Receptors Receptor location Type Ref Ordnance Survey co-ordinates x y z (relative to local ground level), m Knighton Farm Bishops House Farm Doggets Benhole Lane (south) - public footpath Benhole Lane (north) - public footpath Coastal footpath Pixies Mound Private residential Private residential Private residential Outdoor amenity - Public footpath/prow Outdoor amenity - Public footpath/prow Outdoor amenity - Public footpath/prow Outdoor amenity - Historical feature R R R R R R R The coastal footpath (West Somerset Coast Path; see Chapter 17) baseline noise monitoring location is also considered representative of the intertidal zone for assessment of the potential impacts to ecological receptors at that location. The potential impacts are discussed in Chapters 10 and 11. Baseline Noise Survey A baseline noise survey was undertaken between 27 April and 7 May The survey methodology and the identification of appropriate monitoring locations were agreed with West Somerset Council prior to the survey. Hinkley Point C Preliminary Works Environmental Statement

13 The baseline noise survey was undertaken to establish the existing acoustic climate at the nearest noise sensitive receptors. Full details of the survey are provided in the Noise Monitoring Factual Report (Ref 20.4) (Volume 4, Section 20, Part B) along with a complete set of monitoring data All measurements were carried out in accordance with BS 7445: 2003 Acoustics - Description and measurement of environmental noise (Ref 20.18) and all staff involved with noise measurements were either Members of the Institute of Acoustics or held the IoA Certificate of Competence in Environmental Noise Measurement. f) Impact Assessment Methodology Within this Chapter, the generic descriptions used to define the level of significance and the likelihood of occurrence are the same as those given in Chapter 5, where a matrix is presented which compares the magnitude of an impact with the sensitivity of the receptor to determine level of impact significance. Assessment criteria for definition of magnitude and sensitivity for noise and vibration are presented below The assessment of impact significance is the most important step in the EIA process, since it is this which is used to assess whether mitigation is required and also to determine whether mitigation measures have reduced the impact to an acceptable residual impact rating. It is only those impacts assessed as being more than minor which require mitigation. Consequently, impacts rated as negligible or minor are considered to be generally acceptable without the requirement for further mitigation. g) Uncertainties, Limitations and Assumptions Baseline noise surveys were undertaken at a limited number of monitoring locations identified as being representative of groups of sensitive receptors, e.g. residential dwellings in a certain area Assumptions have been made about the type of equipment and machinery to be used during the construction of the jetty and onshore aggregates facility based upon likely methods to be adopted, and previous development project experience but contractors may adopt different working methods to reach the same goals. The assessment presented herein has, therefore, adopted a worst-case scenario wherever possible Baseline Environmental Characteristics a) Existing Noise Levels The dominant noise sources identified during the baseline noise survey included local road traffic, birdsong and surf movement (at a coastal monitoring location). The ambient noise levels were typical of a rural environment (see Table 20.9), dropping to low levels during the night time Baseline noise measurements were undertaken at a height of between 1.2m and 1.5m above ground level, in free-field conditions, in accordance with BS :2003 (Ref 20.18). All measurements were undertaken during suitable meteorological conditions, conducive to obtaining reliable and accurate baseline data, in accordance with the relevant guidance documents. Hinkley Point C Preliminary Works Environmental Statement

14 Table 20.9 Summary of the Range in Baseline Noise Measurements (Baseline Noise Survey April May 2009) Receptor location (refer to Figure 20-1, Volume 3 and the Noise Monitoring Factual Report1) Sound pressure level, db Day Evening (07:00-23:00) (19:00 23:00) Night (23:00 07:00) L Aeq,16hr LA 90,16hr L Aeq,4hr LA90,4hr L Aeq,8hr LA90,8hr Northern application site boundary (coast path) Knighton Farm (residential) Doggets (residential) Wick Farm (residential) Southern boundary of the Southern Construction Phase Area Hinkley Point B Site Induction and Training Centre Notes: # Arithmetic mean of the measured baseline ambient daytime noise levels (L Aeq,15min) at receptor locations between 07:00 and 18:00: Knighton Farm = 46dB L Aeq,T; Doggets = 45dB L Aeq,T; Bishops Farm House = 40dB L Aeq,T; Benhole Lane (S) = 40dB L Aeq,T; Benhole Lane (N) and coastal footpath = 42dB L Aeq,T; and Pixies Mound = 49dB L Aeq,T Monitoring locations were selected as representative of the nearest noise sensitive receptors, which are primarily residential dwellings. In addition, baseline noise measurements were also undertaken at a location in proximity to the coastal public footpath immediately to the north of the application site. It should be noted that baseline noise monitoring was not undertaken at the exact location of the all of the sensitive receptor locations used for the noise impacts assessments. The coastal baseline noise monitoring location is also considered representative of the intertidal zone for assessment of the potential impacts to ecological receptors at that location (considered in Chapters 10 and 11) Further details of baseline noise levels and existing localised noise sources can be found in the Noise Monitoring Factual Report (Ref 20.4) (Volume 4, Section 20, Part B). Hinkley Point C Preliminary Works Environmental Statement

15 b) Sensitivity For each assessment methodology, the overall sensitivity and value relates to human receptors living in proximity to either the application site or affected highways The potential for noise nuisance has also been considered in outdoor public places, such as footpaths or historical features (such as Pixies Mound, south of the Hinkley Point Power Station Complex). Table below provides a summary of the sensitivity of receptors to predicted noise levels, used to determine the significance of potential impacts during jetty construction, operation, dismantling and restoration and, if required, removal and reinstatement. Table Summary of Receptor Sensitivity Receptor Exposure Sensitivity Permanent Residents at Doggets (private dwelling) Continuous long term Medium Residents of Shurton Village Continuous long term Medium Non-Permanent Users of footpaths and PRoWs (Casual walkers and hikers) Transient short term Low Visitors to Pixies Mound Transient short term Low Private residential properties were categorised as having Medium sensitivity, with High sensitivity reserved for locations where very good communication and resting conditions are essential (schools, hospitals, care homes for the elderly or people with learning disabilities). Outdoor public amenity receptor locations were categorised as Low due to the transient nature of human receptors in these locations and the options available to select other locations at any given time The sensitivity of both marine and terrestrial ecology receptors is discussed in Chapters 10 and 11 respectively. c) Do Nothing Scenario The baseline noise and vibration levels at all assessed receptor locations is not expected to change should the development not proceed. The onshore application site would continue to be used for primarily agricultural purposes and as non-operational land of the existing Hinkley Point Power Station Complex; with the activities associated with this and other identified local noise sources persisting (foliage movement, birdsong and surf). Hinkley Point C Preliminary Works Environmental Statement

16 20.5 Assessment of Impacts For the assessment of the impact of increased noise levels, the point of reference is the existing noise environment at existing noise sensitive receptor locations. This has been described above and detailed in the Noise Monitoring Factual Report (Ref 20.4) For the jetty development, the impact of noise and vibration on the existing environment covers the following potential scenarios: potential increase in noise during construction of the offshore and onshore jetty elements and aggregates storage area; potential increase in road traffic noise during construction of the jetty and aggregates storage area; potential vibration generation during construction of the jetty and aggregates storage area; and potential increase in noise during operation of the jetty and aggregates area. a) Impacts during Construction Assessment Scenarios In order to evaluate the noise generation during the jetty development it is necessary to define the various activities that would be undertaken. The different contractors who could be appointed for the jetty development may use different working methods and plant. However, it is possible to undertake a generic assessment of potential construction noise impacts based upon expected methods of working gained from experience with previous similar developments Works associated with construction of the jetty and aggregates handling facility would comprise the following operations that have the potential to generate noise at neighbouring sensitive receptors: ground preparation earthworks (topsoil strip; earthworks; platform development); excavation of fresh rock for surfacing of the aggregates storage area; construction of the aggregates storage area (aggregate stores and cement silos); construction of the jetty bridge onshore; and construction of the jetty bridge and jetty head offshore Construction of the jetty and aggregates storage area is scheduled to take approximately 15 months, during which time specific activities would vary. As a worstcase assessment, three scenarios have been assessed. These represent two distinct points in time when multiple construction activities are expected to be ongoing, as well as possible evening and night-time activities associated with offshore jetty construction (dictated by the tides). In each case, the entire site has been considered, however, the operating machinery that is the shortest distance to the respective receptor location is likely to be the dominant noise source Details of each scenario (including numbers of assumed plant and machinery, and dump truck movements on the service road) are provided in Tables and A description of each assessed scenario is provided below. Hinkley Point C Preliminary Works Environmental Statement

17 Table Construction Works Machinery Assumed for Each Assessed Scenario Machinery Number of Operating Plant Onshore earthworks and onshore jetty construction Onshore aggregates storage area and offshore jetty construction Offshore jetty construction 17t Scraper t Dozer Mini excavator with hydraulic breaker t Tracked excavator t Vibratory roller t mobile telescopic crane Vibratory compactor (Wacker plate) Diesel water pump Pulverizer mounted on excavator (rock breaker) Tracked semi-mobile crusher Dredging ship Piling rig (jack-up platform / land-based) Crane (barge mounted / land-based) Concrete pump and cement mixer truck Forklift truck Scenario 1 Onshore Earthworks and Onshore Jetty Construction At this stage, access to the aggregates storage area would be via a temporary east to west service road. Topsoil stripped from the site would be stockpiled on land to the northeast of the aggregates handling facility. The site would be levelled, and a platform would be formed at +20m AOD using suitable material extracted from a rock extraction area at the south-east corner of the main EPR site. Onshore installation of steel tubular piles would be underway using either drill and drive or pre-drill and concreting the piles in place techniques. These operations would be carried out by onshore piling plant. Scenario 2 Construction of the Aggregates Storage Area and Offshore Jetty Bridge Onshore, preparation of service roads, hardstandings, drainage systems and building foundations would be underway. Construction of the cement silos would also have Hinkley Point C Preliminary Works Environmental Statement

18 commenced. Offshore installation of steel tubular piles would be underway using either drill and drive or pre-drill and concreting the piles in place techniques. These operations would be carried out by offshore (jack-up barge) piling plant. Table Dump Truck Movements on Service Roads Assumed for Each Assessed Scenario Ref Service road Number of Movements per Hour (40t Articulated dump truck) Onshore earthworks and onshore jetty construction Onshore aggregates storage area and offshore jetty construction Offshore jetty construction H1 Temporary Service Road - E- W H2 H3 Temporary Service Road - link to topsoil storage area 1 Temporary Service Road - link to topsoil storage area Scenario 3 Offshore Construction of the Jetty This scenario assumes that only offshore jetty construction activities would be taking place in order to assess the potential noise impacts outside of onshore working hours (i.e. evening and night-time working - dictated by the tides). Offshore installation of steel tubular piles would use either drill and drive or pre-drill and concreting the piles in place techniques. These operations would be carried out by offshore (jack-up barge) piling plant Each of the scenarios described above were taken to represent the typical worst-case scenarios during the proposed jetty and aggregates storage area s construction Octave band noise emission data for each type of construction machinery were obtained from the Appendices of BS :2009 (Ref 20.8). The octave sound power levels for equipment assumed in each model scenario (see Table 20.11) are presented in Table 3, Appendix 20-2, Volume 4. Table identifies the number of vehicle movements on each service road during the assessed scenarios, based upon earthworks volumes calculations For each assessed scenario, it is assumed that the appropriate standard good construction practice outlined in BS :2009 (Ref 20.8) would be followed. This includes: continuous noisy plant to be housed in acoustic enclosures (as practical); use of electrical items of plant instead of diesel plant in especially sensitive locations (as practical); exhaust silencing and plant muffling equipment to be maintained in good working order; Hinkley Point C Preliminary Works Environmental Statement

19 avoid unnecessary revving of engines and switch off equipment; keep internal service routes well maintained and avoid steep gradients where possible; minimise drop height of materials; soft-start piling operations (gradual increase in piling intensity in order to forewarn marine fauna); start up plant and vehicles sequentially rather than all together; and loading / unloading sites to be located away from residential properties and shielded from those properties where practicable. IMPACT: Noise during Construction Table summarises the construction noise levels, predicted using CadnaA modelling in accordance with BS (see Appendix 20-2, Volume 4), at each selected receptor location during each phase of works. Table Summary of Predicted Construction Noise Levels at Identified Sensitive Receptor Locations (Excluding Existing Ambient Noise) Ref Receptor Type Predicted LAeq,T Sound Pressure Level, db (Free-field) Onshore earthworks and offshore jetty construction Onshore aggregates storage area and onshore jetty construction Offshore jetty construction R1 R2 Knighton Farm Bishops House Farm Private residential Private residential R3 Doggets Private residential R4 Benhole Lane (south) Outdoor amenity - Public footpath/prow R5 Benhole Lane (north) Outdoor amenity - Public footpath/prow R6 Coastal footpath Outdoor amenity - Public footpath/prow R7 Pixies Mound Outdoor amenity - Historical feature Figures 20-3 to 20-5, Volume 3 show CadnaA noise contour plots, excluding existing ambient noise levels, for each assessed scenario. Noise prediction modelling was undertaken at a height of 1.8m above ground level for scenarios 1 and 2 (daytime Hinkley Point C Preliminary Works Environmental Statement

20 activities) and, at a height of 4m above ground level for scenarios 3, in order to consider the potential impacts to first floor bedrooms The predicted construction noise levels in the above table do not include existing ambient noise levels at the respective receptor locations and are, therefore, not comparable with the proposed noise magnitude values in Table Tables and 20.15, below, show the effect of adding measured ambient noise levels to these values and therefore provides an indication of potential impacts. Table Summary of Predicted Daytime Ambient Noise Levels at Identified Sensitive Receptor Locations during Construction Works (Including Existing Ambient Noise) Ref Receptor Type Predicted LAeq,T Sound Pressure Level #, db (Free-field) Onshore earthworks and offshore jetty construction Onshore aggregates storage area and onshore jetty construction R1 Knighton Farm Private residential R2 Bishops House Farm Private residential R3 Doggets Private residential R4 Benhole Lane (south) Outdoor amenity - Public footpath/prow R5 Benhole Lane (north) Outdoor amenity - Public footpath/prow R6 Coastal footpath Outdoor amenity - Public footpath/prow R7 Pixies Mound Outdoor amenity - Historical feature Notes: # Predicted construction noise levels include the arithmetic mean of the measured baseline ambient daytime noise levels (L Aeq,15min) at receptor locations between 07:00 and 18:00. Ambient daytime noise levels: Knighton Farm = 46dB L Aeq,T; Doggets = 45dB L Aeq,T; Bishops Farm House = 40dB L Aeq,T; Benhole Lane (S) = 40dB L Aeq,T; Benhole Lane (N) and coastal footpath = 42dB L Aeq,T; and Pixies Mound = 49dB L Aeq,T. Hinkley Point C Preliminary Works Environmental Statement

21 Table Summary of Predicted Evening and Night-time Ambient Noise Levels at Identified Sensitive Receptor Locations during Construction Works (Including Existing Ambient Noise) Ref Receptor Type Predicted LAeq,T Sound Pressure Level#, db (Free-field) during Offshore Jetty Construction Evening Night-time R1 Knighton Farm Private residential R2 Bishops House Farm Private residential R3 Doggets Private residential R4 Benhole Lane (south) Outdoor amenity - Public footpath/prow R5 Benhole Lane (north) Outdoor amenity - Public footpath/prow R6 Coastal footpath Outdoor amenity - Public footpath/prow R7 Pixies Mound Outdoor amenity - Historical feature Notes: # Predicted construction noise levels include the arithmetic mean of the measured baseline ambient noise levels (L Aeq,15min) at receptor locations between 18:00-23:00 (evening) and 23:00-07:00 (night). Ambient noise levels: Knighton Farm = 36dB L Aeq,evening, 34dB L Aeq,night; Doggets = 39dB L Aeq,evening, 37dB L Aeq,night; Bishops Farm House = 36dB L Aeq,evening, 34dB L Aeq,night; Benhole Lane (S) = 36dB L Aeq,evening, 34dB L Aeq,night; Benhole Lane (N) and coastal footpath = 44dB L Aeq,evening, 44dB L Aeq,night; and Pixies Mound = 49dB L Aeq,evening, 49dB L Aeq,night In Table it can be seen that, at the assessed residential receptor locations, the highest predicted noise level during daytime construction works is 47dB L Aeq, 1hr at Knighton Farm and Doggets. By comparison with the criteria in Table 20.3, this equates to a very low magnitude noise level, on a receptor of medium sensitivity (see Table 20.10). This equates to a minor adverse impact at Knighton Farm and Doggets. The predictions indicate that the proposed normal working daytime noise threshold criteria of 65dB L Aeq, 1hr would not be exceeded at any residential receptor location Offshore construction of the proposed jetty would continue outside of the proposed onshore working hours, including night-time working (dependent upon suitable tides). The predicted ambient noise levels, at the assessed residential receptor locations (see Table 20.15), are of very low magnitude when compared with the criteria in Table This equates to a minor adverse impact at the nearest residential dwellings. Hinkley Point C Preliminary Works Environmental Statement