Appendix D. Noise and Vibration Assessment · 2014. 6. 11. · Table 2-1 DMRB Noise Changes and...

A34 Chilton North Facing Slip Roads Environmental Assessment Report

Appendix D. Noise and Vibration Assessment

A34 Chilton North Facing Slip Roads Noise Assessment Oxfordshire County Council

April 2014

A34 Chilton North Facing Slip Roads Noise Assessment

Atkins A34 Chilton North Facing Slip Roads | Version 1.0 | March 20 2014 | 5126689

Notice This document and its contents have been prepared and are intended solely for Oxfordshire County Council’s information.

Atkins Acoustics Noise and Vibration assumes no responsibility to any other party in respect of or arising out of or in connection with this document and/or its contents.

This document has 39 pages including the cover.

Revision history Job number: 5126689 Document ref: 2014/Apr/05

Revision Purpose description Originated Checked Reviewed Authorised Date

1.0 Issue LM FR FR IE 15/04/14 2.0 Issue LM FR FR IE 17/04/14 3.0 Issue LM FR FR 23/04/14

Change Log

Rev Section Description

2.0 1 Updated the description of the Development to reflect the latest design

3.0 6 Updated the construction noise assessment to reflect changes to the under-bridge design

Hold List Rev Section Description



Table of contents Chapter Pages Executive summary 6

1. Introduction 8 1.1. Description of the Development 8

2. Consultation 9

3. Assessment Criteria 10 3.1. Operational Noise Assessment Criteria 10 3.2. Operational Vibration Assessment Criteria 11 3.3. Construction Noise Assessment Criteria 12 3.4. Construction Vibration Assessment Criteria 12

4. Baseline Noise Levels 14

5. Operational Noise Assessment 15 5.1. Short term assessment 16 5.2. Long term assessment 20 5.3. Assessment of permanent traffic induced vibration impacts 22

6. Construction Noise Assessment 23 6.1. Construction Noise Mitigation 28

7. Conclusions 29

Appendices 30

Appendix A. Maps of study area and sensitive receptors 31

Appendix B. Noise contours 33

Tables Table 2-1 DMRB Noise Changes and Magnitude of Opening Year Impacts (short term) 10 Table 2-2 DMRB Noise Changes and Magnitude of Design Year Impacts (long term) 11 Table 2.3 WHO recommended night noise guidelines values 11 Table 2-4 BS 5228 Significance Criteria 12 Table 2-5 BS 5228 Part 2 Guidance on Human Response to Vibration Levels 13 Table 2-6 Transient vibration guide values for structural damage 13 Table 4-1 Opening Year Impacts at Selected Receivers (DS1) 17 Table 4-2 Short term impacts (changes on scheme opening) DS1 18 Table 4-3 Opening Year Noise Impacts at Selected Receivers Including Cumulative Effects of Other

Developments (DS2 data) 18 Table 4-4 Short Term Road Traffic Noise Impact (DS2) 19 Table 4-5 Design Year ‘With Scheme’ Noise Impacts for Selected Receivers 20 Table 4-6 Design Year 'Without Scheme' Noise Impacts at Selected Receivers Error! Bookmark not defined. Table 4-7 Long Term Road Traffic Noise Impact 21 Table 4-8 Long Term Road Traffic Night Time Noise Impact 22 Table 5-1 Activity Noise Level - Earthworks 23 Table 5-2 Activity Noise Level - Road Construction 24 Table 5-3 Activity Noise Level - Retaining Wall 24 Table 5-4 Results for Earthworks 25



Table 5-5 Results for Road Construction 26 Table 5-6 Results for Retaining Wall 27

Figures Figure A-1 Map of study area 31 Figure A-2 Map of study area 32 Figure B-1 DMRB Opening Year Noise Change Contours (DS1 data) 34 Figure B-2 DMRB Opening Year Noise Change Contours (DS2 data) 35 Figure B-3 DMRB Design Year Noise Change Contours 36 Figure B-4 Design Year Noise Levels at Night (Lnight) 37

Atkins A34 Chilton North Facing Slip Roads | Version 1.0 | March 20 2014 | 5126689 6

Executive summary The Chilton Junction of the A34 is a grade-separated junction located approximately 15 miles south of Oxford where the A34 and A4185 Newbury Road intersect.

To improve transport links from the national road network to the Science Vale Enterprise Zone, it is proposed to add north-facing slip roads to Chilton Junction. This will involve developing a green field site in the North Wessex Downs Area of Outstanding Natural Beauty (AONB) to provide a new northbound on-slip, a new southbound off-slip, two new roundabouts connecting the slip roads to the A4185. A byway currently passes under the A34 and a new under-bridge is required adjacent, and to the wet of the existing structure to carry the proposed northbound on-slip over the existing byway.

Atkins Acoustics Noise and Vibration was commissioned to estimate the noise and vibration impacts at sensitive receptors in the surrounding area during the operational and construction phases of the Development. The guidance within the Design Manual for Roads and Bridges (DMRB) was followed to determine if a significant effect would arise once the Development is operation in the short term and the long term. The thresholds for triggering a detailed assessment are if there is a change in daytime traffic noise impacts of at least 1 dB LA10,18h in the short term (Opening Year 1) or 3 dB LA10,18h in the long term (typically 15 years after project opening). The effects of operational noise during the night time were also assessed, where a detailed assessment will be required if there is a change in night-time traffic noise impacts of 3 dB Lnight,outside in the long term where the Lnight,outside is predicted to be greater than 55 dB Lnight,outside in any scenario.

A construction noise assessment was carried out using the ABC methodology outlined in BS 5228-1:2009 + A1:2014 “Code of practice for noise and vibration control on construction and open sites – Part 1”. It is assumed that all of the residential and non-residential receptors in the study area are very noise sensitive and were assigned a noise threshold of 65 dB LAeq, where the potential exists for a potential significant effect to occur if this threshold level is exceeded.

The DMRB assessment identified a short-term minor adverse impact at the UK Atomic Energy Authority (UKAEA) and a garden centre located close to Chilton Junction, based on traffic data modeling that included changes to Chilton Junction and Milton Junction only. A minor adverse impact was also predicted at two dwellings located west of the Garden Centre, for which noise mitigation may be required.

An additional assessment of short-term impacts was completed that included the effects of other developments occurring close to the study area which that would be operational during the opening year. This assessment showed that no significant adverse impacts would occur at residential receptors. The traffic data for this assessment included changes associated with other developments at Harwell, Hagbourne Hill, Featherbed Lane, Wantage Eastern Link, Didcot North East Link, and Science Bridge.

A long-term minor adverse impact was identified at five residential receptors at Townsend Road as a result of the Development during daytime hours. No significant adverse impacts were highlighted in the night time noise assessment, however, this is based on an indicative assessment using a conversion factor from the 18 hour daytime traffic flows. Further investigation should be undertaken using hourly night-time traffic flows.

Initial indications for the wider area road network are that the Chilton Slips scheme, in isolation, would have minimal effect on roadside noise levels. When taking into account the Chilton Scheme in combination with other proposed small road schemes, the beneficial changes on the wider area road network are likely to outweigh the adverse changes in both the short and the long term; however this is subject to further investigation taking into account the locations of the affected routes and the numbers of properties affected in each scenario

The Vale of White Horse District Council informed Atkins that a plot of land opposite UKAEA may be released for a housing development. Assuming that the housing development is approved in future, the


noise contours produced in this assessment suggest that there will be minor to moderate adverse noise impact at the housing development in the short term and a negligible adverse to moderate adverse impact was predicted in the long term. The severity of the range of impacts in the short and the long term will depend on the layout of the houses within the plot of land under consideration.

The Development is situated within an AONB, with a public byway intersecting Chilton Junction. Noise levels exceeding the threshold for a potentially significant effect were predicted at the sections of the public byway closest to earthworks and retaining wall construction. However, the public byway will be closed during the construction phase of the scheme which negates the necessity for screening specifically for the public byway.

During the construction phase of the Development, a potential temporary significant effect was predicted at residential receptors at Manor Close during the construction of the eastern roundabout to accommodate the north-facing off-slip road. The addition of a temporary noise barrier to the southern perimeter of these works should remove the significant effect at Manor Close. However, best practice, considerate working hours as well as frequent and open communications with stakeholders will help to reduce the residual impact of construction noise.


1. Introduction 1.1. Description of the Development The Chilton Junction of the A34 is a grade-separated junction located approximately 15 miles south of Oxford where the A34 and A4185 Newbury Road intersect. At present, this junction consists of south-facing slip roads only, so that no access or egress is possible to the north of the junction.

To improve transport links from the national road network to the Science Vale Enterprise Zone, it is proposed to add north-facing slip roads to Chilton Junction. The proposal consists of the following alterations to Chilton Junction:

A new A34 northbound on-slip, A new A34 southbound off-slip, Two new roundabouts connecting the slip roads to the A4185, and A new under-bridge adjacent and to the west of the existing structure to carry the proposed

northbound on-slip over the existing byway.

The length of new slip roads will be approximately 850m.

The nearest centres of population to Chilton Junction are the villages of Chilton (500m) and Upton (2.3 km). However, the nearest residential receptors are located at Manor Close which is approximately 55m south of the new eastern roundabout connecting the proposed southbound off-slip road. There is a commercial property located approximately 65m away from the site and a primary school located to the south west of Chilton Junction.

Chilton Junction is located within the North Wessex Downs Area of Outstanding Natural Beauty (AONB), which is designated as an environmentally sensitive area. The proposal would involve the development of a green field site and a change in usage of an existing agricultural area.


2. Consultation Atkins Acoustics Noise and Vibration was commissioned to undertake an assessment of the likely noise impacts arising during the operational and construction phases of the Development. Prior to undertaking this assessment, the Environmental Health Officer at Vale of White Horse District Council (VWHDC) was contacted to agree the assessment methodology and to discuss and identify any issues regarding the Development. The information gained through consultation is presented in Table 2-1.

Table 2-1 Consultation with VWHDC

Contact Details Assessment Type Comment Alec Natton at (VWHDC), 02/04/2014

Baseline Noise Survey

Atkins proposed to undertake a CRTN shortened measurement procedure survey for one day and this was accepted by VWHDC.

Operational Noise Atkins was informed of a recently built development to the south west of Chilton Junction that should be considered in the assessment. Scattered housing around the south facing slip roads was also mentioned by VWHDC and it was acknowledged that these were less likely to be adversely impacted. VWHDC commented that there is pressure to release land for housing in the general area and it is likely that a new housing development will come forward for the parcel of land on the opposite side of the A4185 from the UK Atomic Energy Authority (UKAEA) offices. This particular area of land is not committed for development and Atkins stated that a qualitative comment would be made about this. Atkins confirmed the traffic data that would be used for this assessment took into account the growth due to future developments.

Construction Noise VWHDC explained that there are no particular policies relating to construction noise, however, they do not usually enter into S61 prior consent agreements. The use of BS 5228 as an assessment methodology and a source of advice on noise and vibration management (e.g. piling methods) was agreed. VWHDC requested the opportunity to discuss and comment on construction proposals.


3. Assessment Criteria 3.1. Operational Noise Assessment Criteria The operational impact of the Development in this report is determined following the Simple Assessment methodology as outlined in the Design Manual for Roads and Bridges Volume 11, Section 3, Part 7, HD 213/11 (2011). DMRB provides guidance on the significance of changes in road traffic noise, identifying that changes in noise smaller than 1 dB(A) are not perceptible. Assuming no changes to the proportion of heavy vehicles or traffic speeds, an increase in traffic volume of 25% is required to alter the noise levels by 1 dB(A).

A Simple Assessment requires a calculation of the short term and long term impacts of the Development at noise-sensitive receptors through a comparison of the following design scenarios, based on projected baseline and design year traffic data:

1) Do-Minimum scenario in the baseline year against the Do-Something scenario in the baseline year (short term assessment)

2) Do-Minimum scenario in the baseline year against Do-Something in the future assessment year (long term assessment).

The noise change is determined using the calculation method provided in the Department for Transport Memorandum, Calculation of Road Traffic Noise (1988). This document assesses road traffic noise over an 18 hour period from 06:00 to 24:00, using annual average weekday traffic (AAWT) flows. The basic noise level for a road segment can be calculated using the traffic flow, traffic speed and percentage heavy vehicles for a road segment. Additional guidance on calculation, which updates the CRTN methodology, is provided in Annex 4 of DMRB.

DMRB sets out threshold criteria, which, where it is possible that they will be met or exceeded, trigger the requirement for a detailed traffic noise assessment. The threshold criteria are as follows:

Change in daytime traffic noise impacts in the short term of 1 dB LA10,18h (Opening Year 1). Change in daytime traffic noise impacts in the long term of 3 dB LA10,18h (typically 15 years after

project opening). Change in night-time traffic noise impacts of 3 dB Lnight,outside in the long term where the Lnight,outside

is predicted to be greater than 55 dB Lnight,outside in any scenario.

The magnitude of the changes in noise level at each noise sensitive receptor is categorised according to the criteria displayed in Table 3-1 and Table 3-2.

Table 3-1 DMRB Noise Changes and Magnitude of Opening Year Impacts (short term)

Noise change, LA10,18h Magnitude of Impact

0 No change

0.1 – 0.9 Negligible

1.0 – 2.9 Minor

3.0 – 4.9 Moderate

5+ Major


Table 3-2 DMRB Noise Changes and Magnitude of Design Year Impacts (long term)

Noise change, LA10,18h Magnitude of Impact

0 No change

0.1 – 2.9 Negligible

3.0 – 4.9 Minor

5.0 – 9.9 Moderate

10+ Major

The World Health Organisation’s (WHO) Night Noise Guidelines for Europe published in 2009 sets out a recommended Night Noise Guideline (NNG) to protect the public, including most vulnerable groups such as children, the chronically ill and the elderly, from the adverse health effects of night noise. It also provides an Interim Target (IT) for situations where the achievement of the NNG is not feasible in the short term. The two target noise levels are set out below in Table 3.3.

Table 3.3 WHO recommended night noise guidelines values

Target Lnight,outside dB a Interim Target (IT) 55

Night Noise Guideline (NNG) 40 a) The A-weighted long-term average free-field sound level as defined in ISO 1996-2:1987, determined over all the night periods of a year; in which: the night is eight hours (usually 23:00 – 07:00 hours).

3.2. Operational Vibration Assessment Criteria Traffic vibration can either be ground-borne or airborne. Ground-borne vibration arising from the interaction between vehicles’ wheels and the road surface can be perceptible in nearby buildings if heavy vehicles pass over irregularities in the road. Extensive research on a wide range of buildings of various ages and types has found no evidence to indicate that traffic induced vibrations are a source of significant damage to buildings1. As significant ground-borne vibrations are only likely to be generated where there are irregularities in the road surface, this is not generally an important consideration for new roads.

It is stated in DMRB that an adverse impact from ground-borne vibration is achieved if either of the following occurs:

The level of vibration at a receptor increases to, or exceeds, a level of 0.3 mm/s, or An existing level of vibration above 0.3 mm/s is predicted to increase.

Airborne vibration can be produced by low frequency sound emitted by vehicle engines and exhausts and can occur to some extent along any type of road. Airborne vibration may result in detectable vibrations in building elements (e.g. windows and doors). The disturbance produced by airborne vibration is closely linked to traffic noise levels and can therefore be assessed based on noise predictions.

1 Watts, G.R. (1990). Traffic induced vibration in buildings. TRRL RR246. Transport and Road Research Laboratory.


3.3. Construction Noise Assessment Criteria Annex E of BS 5228-1:2009 + A1:2014 “Code of practice for noise and vibration control on construction and open sites – Part 1” presents various methods of determining the significance of noise effects due to construction works. In this assessment, the ABC method detailed in Annex E.3.2 has been used, where for the appropriate period (night, evening/ weekends or day), the measured ambient noise level is rounded to the nearest 5 dB. This is then compared with the estimated construction noise level. If the construction noise level exceeds the appropriate category value, then there is potential for a significant effect to occur. The example threshold for significant effects at dwellings is shown below in Table 3-4.

Table 3-4 BS 5228 Significance Criteria

Assessment category and threshold value period (LAeq)

Threshold value, in decibels (dB)

Category A Category B Category C

Night-time (23:00-07:00) 45 50 55

Evenings (19:00-23:00 weekdays) and weekends (13:00-23:00 Saturdays

and 07:00-23:00 Sundays)

55 60 65

Daytime (07:00-19:00) and Saturdays (07:00-13:00)

65 70 75

The values in Category A, B and C are the threshold values to be used to determine the potential for significance at a noise sensitive receptor, based on ambient noise levels rounded to the nearest 5 dB. A receptor is categorised by comparing its rounded ambient noise level with the values assigned to Category A for the relevant time period, and is then categorised depending on whether the rounded ambient noise levels are less than, equal to, or higher than the values in Category A column, respectively. For example, if the rounded daytime ambient noise level is below 65 dB(A), then it is a Category A receptor and the threshold for potential significance is 65 dB(A). If the rounded daytime ambient noise level is equal to 65 dB(A), then the receptor is assigned to Category B and the threshold level is 70 dB(A).

The response of the human hearing system is logarithmic rather than linear in behaviour, and able to detect a noise level difference of about 1 dB between two steady sounds, when presented in rapid succession under controlled laboratory conditions. The smallest change in environmental noise that is generally noticed by an individual over a period of time is about 3 dB. A 10 dB change approximates to a subjective doubling or halving of loudness.

BS 5228 provides generic source noise data for various items of plant used on open sites along with methods for calculating the effects of these activities and their respective noise levels at nearby noise sensitive properties. It also provides methods for calculating the noise levels of plant and vehicles moving along haul roads. The calculation method takes into account distance, ground effects, reflections from surfaces, and screening by obstacles.

3.4. Construction Vibration Assessment Criteria BS 5228-2:2009 “Code of practice for noise and vibration control on construction and open sites – Part 2”, gives guidance on vibration levels that could be used to assess the likely impacts of construction activities, including piling, on the environment and people. The main vibration impacts could arise from piling activities or heavy construction vehicle movements near sensitive receivers (typically within 20m).

Annex B of BS 5228 Part 2 gives guidance on the significance of vibration effects in terms of human response to vibration and structural response to vibration. This information is displayed in Table 3-5 and Table 3-6 respectively.


Table 3-5 BS 5228 Part 2 Guidance on Human Response to Vibration Levels

Vibration Level Effect 0.14 mm/s Vibration might be just perceptible in the most sensitive situations for most

vibration frequencies associated with construction. At lower frequencies, people are less sensitive to vibration

0.3 mm/s Vibration might be just perceptible in residential environments 1.0 mm/s It is likely that vibration of this level in residential environments will cause

complaint, but can be tolerated if prior warning and explanation is given to residents

10 mm/s Vibration is likely to be intolerable for any more than a brief exposure at this level

Table 3-6 Transient vibration guide values for structural damage

Type of building Peak component particle velocity in frequency range of predominant pulse

4 Hz to 15 Hz 15 Hz and above Reinforced or framed structures,

industrial or heavy commercial buildings 50 mm/s at 4 Hz and above 50 mm/s at 4 Hz and above

Unreinforced or light framed structures, residential or light commercial buildings

15 mm/s at 4 Hz increasing to 20 mm/s at 15 Hz

20 mm/s at 15 Hz increasing to 50 mm/s at 40 Hz and

above

Note 1: Values referred to are at the base of the building.

Note 2: For line 2, at frequencies below 4 Hz, a maximum displacement of 0.6mm (zero to peak) is not to be exceeded.


4. Baseline Noise Levels A baseline noise survey is not a requirement of a DMRB Simple level assessment and one has not been undertaken as part of this assessment. However, it is proposed that a baseline noise survey will be carried out in order to provide information on existing noise levels in the area, which are not readily picked up from predictions alone and in order to provide a baseline for assessing construction noise impacts. The following procedure is proposed.

4.1. Measurement Procedure The baseline noise survey will be undertaken at approximately four to six locations following the shortened measurement procedure described in CRTN. This requires all measurements to be completed over three consecutive hours between 10:00 and 17:00. The measurements will be at least 15 minutes in duration to fulfill the sampling requirements stipulated in Paragraph 41.2 of CRTN.

During the baseline noise survey, the following acoustic parameters will be recorded as a minimum:

LAeq,T – The A-weighted equivalent continuous sound pressure level over a period of time T. Representative of the ‘average’ sound pressure level over a given period.

LAmax – The maximum sound pressure level occurring within the measurement period LA10,T – The 10th percentile level or the noise level exceeded for 10% of the measurement period. LA90,T – The 90th percentile level or the noise level exceeded for 90% of the measurement. This

indicator is representative of the background noise level.

The noise survey will be performed during favourable meteorological conditions, i.e. when no precipitation is occurring and when the road surfaces are dry. Where possible the noise survey will be carried out when wind conditions meet those prescribed in CRTN; where this is not practicable, full details of the wind speed and direction will be recorded. In any case, the wind speed at the microphone will not exceed 10 m/s during the measurement from any direction.

The noise measurements will be conducted at a height of 1.2m above ground level using a field-calibrated integrating sound level meter. Where possible, traffic counts will be undertaken concurrently with noise measurements.


5. Operational Noise Assessment DMRB 11:3:7 defines the total study area as being that which is within 1km of any new, improved or any existing routes which are being bypassed between the start and end points of the physical works relating to the road scheme. Within this 1km boundary noise predictions are required within 600m of the carriageway edges of the identified routes and within 600m of any other affected routes within the 1km boundary (this is termed ‘the calculation area’). An affected route is one where the threshold criteria are likely to be exceeded. Any routes outside of the 1km boundary that are likely to experience increases above the threshold criteria also need to be identified and a 50m boundary from the carriageway edge defined for these routes.

The calculation procedure of CRTN has been implemented for the assessment of roads within a 1km area of the physical works by the use of Noisemap Five environmental noise modelling software, which calculates fully in accordance with the methodologies of CRTN and DMRB.

For affected routes outside of this area a basic noise level (roadside) noise level calculation has been undertaken to ascertain the magnitude of changes on the wider road network. At this stage, full property counts for affected routes in the wider area have not been undertaken and therefore only a qualitative assessment of these changes is reported here.

The Noisemap software builds a three dimensional model of features which may affect the generation and propagation of noise. These features have been captured from the following data sources:

Ordnance Survey Mastermap® data to define the alignments of existing roads and locations of houses and other structures; and,

Three-dimensional topographical survey data for details of cuttings, embankments and existing and proposed road heights as a result of the Development.

Other inputs into the programme also include:

Type of intervening ground between each road segment and each receiver; 18 hour annual average weekday traffic flow (AAWT); Percentage of heavy goods vehicles (HGV); Annual average speed; and, Nature of the road surface.

The traffic data for this assessment was provided by Atkins Highways and Transport and based on an opening year of 2016 and a future assessment year of 2030. The future assessment year in this assessment is therefore a year earlier than the usual 15 year design period required by DMRB; however any differences due to traffic growth over an additional one year period would be negligible.

The traffic data included two different ‘Do-Something’ scenarios for the opening year and only one ‘Do-Something’ scenario for the future assessment year, as described below:

1. Do-Something 1 2016 (DS1) – The traffic data is based on the commissioning of the north-facing slip roads at Chilton Junction and the completion of the Milton Slip Roads scheme2 in time for the opening year of the Development.

2. Do-Something 2 2016 (DS2) – The traffic data in this scenario models the changes associated with the completion of the Milton and Chilton Slip Road schemes (as described above for DS1), but also includes traffic changes relating to other proposed local developments at Harwell, Hagbourne Hill, Featherbed Lane, Wantage Eastern Link, Didcot North East Link, and Science Bridge.

2 The construction of the Milton slip roads scheme will commence in October 2014 and will be a completed scheme by the opening year of the Chilton Junction Development.


3. Do-Something 2030 – The traffic data in this scenario models the changes associated with the completion of the Milton and Chilton Slip Road schemes and the following proposed local developments: Harwell (including employment developments), Hagbourne Hill, Featherbed Lane, Wantage Eastern Link, Didcot North East Link, Didcot Western Extension, and Science Bridge.

The Do-Minimum traffic data for the opening year and the future assessment year was based on following assumptions regarding local developments:

1. Do-Minimum 2016 – The traffic data assumed that the Milton Slip Roads scheme was complete 2. Do-Minimum 2030 – The traffic data was included changes associated with Milton Slip Roads,

Harwell (including employment developments), Hagbourne Hill, Featherbed Lane, Wantage Eastern Link, Didcot North East Link, Didcot Western Extension, and Science Bridge.

To complete this assessment, the DS1 data was used to establish the short term noise impacts of the design in the opening year, independent of other road schemes or developments in the area. An additional short term noise impact assessment using the DS2 data has also been completed to understand the likely impact of other developments occurring concurrently on the opening year noise levels and to facilitate a comparison with the long term assessment as the traffic data for DS2 2016 and DS 2030 are based on similar assumptions.

At this stage of the assessment, estimates of property counts have been made from available mapping resources3. Currently, no mapping is available to ascertain the quantity of dwellings at the new development at Chilton Field located west of the Development near the Garden Centre and Chilton Primary School. As a result of this, these properties are not included in the DMRB assessments although the predicted noise levels at the new development are reported for indicative purposes. Furthermore, it is assumed that all of the buildings at Harwell (A4185 between Perimeter Road and Fermi Avenue) are non-residential and are not included in the DMRB assessment, however, the predicted noise levels at the peripheral buildings located close to the A4185 Newbury Road are reported for each scenario (Frome Road, Library Avenue, Gemini Building).

5.1. Short term assessment The noise levels presented are the predicted levels at the worst affected floor and facade for each property (1.5m or 4m above ground level) or at 1.5m above ground level for open spaces. All comparisons take a ‘worst case scenario’ i.e. the highest adverse or least beneficial change has been reported.

5.1.1. Do-Something 1 2016 A representative selection of the modelling results is presented in Table 5-1. The locations of these properties are shown in Figure A-1 and Figure A-2.

3 Google Maps and Bing Maps, accessed 14/04/2014.


Table 5-1 Opening Year Impacts at Selected Receivers (DS1)

Location Worst affected floor

DM2016 (LA10,18h, dB)

DS2016 (LA10,18h, dB)

Difference (dB)

Impact significance

UKAEA 0 60.4 61.8 1.4 Minor Adverse 2 Manor Close 1 62.1 62.8 0.7 Negligible 5 Manor Close 1 62.2 63.1 0.9 Negligible 8 Manor Close 1 62.8 63.4 0.6 Negligible 5 Limetrees 1 56.5 57.0 0.5 Negligible 8 Limetrees 1 56.7 57.1 0.4 Negligible 10 Limetrees 1 56.7 57.2 0.5 Negligible Garden Centre 1 58.6 59.6 1.0 Minor Adverse White Road 1 66.5 66.4 -0.1 Negligible Chilton Primary School 1 58.9 58.9 0.0 No change Severn Road 1 51.4 51.6 0.2 Negligible Frome Road 1 50.6 50.8 0.2 Negligible Gemini Building, Fermi Avenue

0 54.6 54.6 0.0 No change

Library Avenue 1 45.9 46.1 0.2 Negligible Chilton House Apartments and Cottages

1 62.9 63.6 0.7 Negligible

Village Hall 1 59.5 59.4 -0.1 Negligible The Paddock 0 61.3 61.2 -0.1 Negligible Building near SB on slip 1 74.0 73.8 -0.2 Negligible Lower Road 1 59.5 58.8 -0.7 Negligible New Development 1 58.1 58.7 0.6 Negligible Sports Pitch 0 57.7 57.2 -0.5 Negligible Ambulance and Fire Station 1 65.2 64.7 -0.5 Negligible Byway 1 0 63.3 64.0 0.7 Negligible Byway 2 0 62.8 63.4 0.6 Negligible

Table 5-2 shows the noise changes at 410 receptors in the 1km study area, categorised into the noise change bands following the magnitude impact ratings as required by DMRB. Noise contours indicating the short term change in noise levels in the opening year are shown in Figure B-1 in Appendix B4.

4 Please note that the noise change contours are representative of LA10,18h noise levels at 4m above ground (first floor height), calculated on a 25m grid and therefore it is possible to get small discrepancies between the modelled receptor noise levels and the graphical display in the noise contours .


Table 5-2 Short term impacts (changes on scheme opening) DS1

Change in noise level Number of dwellings

Number of other sensitive receptors

Increase in noise level, LA10, 18h

0.1 - 0.9 129 5 1 - 2.9 2 2 3 - 4.9 0 0

≥5 0 0

No Change = 0 22 1

Decrease in noise level, LA10, 18h

0.1 - 0.9 239 10 1 - 2.9 0 0 3 - 4.9 0 0

≥5 0 0

Table 5-2 shows that of the 410 receptors considered in this assessment, 406 were predicted to experience a negligible change or no change on the opening of the Development. A minor noise increase was calculated at 2 dwellings positioned immediately west of the Garden Centre and 2 non-residential receptors (UKAEA and the Garden Centre).

Effects on the Wider Area Road Network – DS1

The effect of opening the Chilton north facing slip roads has a minimal effect on the wider area road network in terms of noise, with only Chilton Road, situated just outside of the 1km zone, showing a minor increase in noise whilst a small number of other links show minor decreases.

5.1.2. Do-Something 2 2016 A representative selection of the modelling results is presented in Table 5-3. The locations of these properties are shown in Figure A-1 and Figure A-2.

Table 5-3 Opening Year Noise Impacts at Selected Receivers Including Cumulative Effects of Other Developments (DS2 data)


DM2016 (LA10,18h, dB)

DS2016 (LA10,18h, dB)

Difference (dB)

Impact significance

UKAEA 1 62.4 63.8 1.4 Minor Adverse 2 Manor Close 1 62.1 62.8 0.7 Negligible 5 Manor Close 1 62.2 63.1 0.9 Negligible 8 Manor Close 1 62.8 63.6 0.8 Negligible 5 Limetrees 1 56.5 57.0 0.5 Negligible 8 Limetrees 1 56.7 57.3 0.6 Negligible 10 Limetrees 1 56.7 57.5 0.8 Negligible Garden Centre 1 58.6 59.2 0.6 Negligible White Road 0 64.2 64.2 0.0 No change Chilton Primary School 1 58.9 58.8 -0.1 Negligible



DM2016 (LA10,18h, dB)

DS2016 (LA10,18h, dB)

Difference (dB)

Impact significance

Severn Road 1 51.4 51.5 0.1 Negligible Frome Road 1 50.6 50.6 0.0 No change Gemini Building, Fermi Avenue

0 54.6 54.2 -0.4 Negligible

Library Avenue 1 45.9 45.5 -0.4 Negligible Chilton House Apartments and Cottages

1 62.9 63.6 0.7 Negligible

Village Hall 1 59.5 59.4 -0.1 Negligible The Paddock 1 63.5 63.3 -0.2 Negligible Building near SB on slip 1 74.0 73.8 -0.2 Negligible Lower Road 1 59.5 58.7 -0.8 Negligible New Development 1 58.1 58.5 0.4 Negligible Sports Pitch 0 57.7 55.9 -1.8 Minor Beneficial Ambulance and Fire Station 1 65.2 63.4 -1.8 Minor Beneficial Byway 1 0 63.3 64.1 0.8 Negligible Byway 2 0 62.8 63.4 0.6 Negligible

Table 5-4 shows the noise changes at 410 receptors in the 1km study area, categorised into the noise change bands following the magnitude impact ratings as required by DMRB. Noise contours indicating the short term change in noise levels in the opening year are shown in Figure B-2 in Appendix B.

Table 5-4 indicates that of the 410 sensitive receptors considered in this assessment, a no change or negligible impact was predicted at 390 receptors in the opening year of the Development. A minor adverse impact was predicted at one receptor (UKAEA) and minor benefits were forecasted at 19 receptors located in the region of A4185 Newbury Road between Curie Road and Perimeter Avenue.

Table 5-4 Short Term Road Traffic Noise Impact (DS2)




0.1 - 0.9 131 4 1 - 2.9 0 1 3 - 4.9 0 0

≥5 0 0

No Change = 0 34 1


0.1 - 0.9 210 10 1 - 2.9 17 2 3 - 4.9 0 0

≥5 0 0


Effects on the Wider Area Road Network – DS2

The effect of the DS2 traffic scenario, which includes a number of other small road schemes, is to give rise to some minor increases and minor decreases in noise on a number of routes in the wider study area, and, in a small number of cases, moderate increases or decreases. Early indications are that the beneficial changes outweigh the adverse changes, however, the actual impact will depend on the locations of the changes and the numbers of affected receptors.

5.2. Long term assessment

5.2.1. Daytime assessment The noise levels presented are the predicted levels at the worst affected floor and facade for each property (1.5m or 4m above ground level) or at 1.5m above ground level for open spaces. All comparisons take a ‘worst case scenario’ i.e. the highest adverse or least beneficial change has been reported.

A representative selection of the modelling results is presented in Table 5-1. The locations of these receptors are shown in Figure A-1 and Figure A-2.

Table 5-5 Future Assessment Year ‘With Scheme’ Noise Impacts for Selected Receivers


DM2016 (LA10,18h, dB)

DS2030 (LA10,18h, dB)

Difference (dB)

Impact significance

UKAEA 1 62.4 63.7 1.3 Negligible 2 Manor Close 1 62.1 63.1 1.0 Negligible 5 Manor Close 1 62.2 63.3 1.1 Negligible 8 Manor Close 1 62.8 63.8 1.0 Negligible 5 Limetrees 1 56.5 57.3 0.8 Negligible 8 Limetrees 1 56.7 57.3 0.6 Negligible 10 Limetrees 1 56.7 57.6 0.9 Negligible Garden Centre 1 58.6 59.8 1.2 Negligible White Road 1 66.5 66.3 -0.2 Negligible Chilton Primary School 1 58.9 58.7 -0.2 Negligible Severn Road 1 51.4 51.5 0.1 Negligible Frome Road 1 50.6 50.7 0.1 Negligible Gemini Building, Fermi Avenue

0 54.6 54.4 -0.2 Negligible

Library Avenue 1 45.9 45.8 -0.1 Negligible Chilton House Apartments and Cottages

0 62.0 65.3 3.3 Minor Adverse

Village Hall 1 59.5 59.2 -0.3 Negligible The Paddock 1 63.5 63.1 -0.4 Negligible Building near SB on slip 1 74.0 73.4 -0.6 Negligible Lower Road 1 59.5 58.6 -0.9 Negligible New Development 0 58.1 58.6 0.5 Negligible Sports Pitch 0 57.7 55.9 -1.8 Negligible Ambulance and Fire Station 1 65.2 63.4 -1.8 Negligible



DM2016 (LA10,18h, dB)

DS2030 (LA10,18h, dB)

Difference (dB)

Impact significance

Byway 1 0 63.3 63.8 0.5 Negligible Byway 2 0 62.8 63.3 0.5 Negligible

The results in Table 5-5 generally indicate a negligible impact in the design year of the Development. The most significant impact was predicted at Chilton House Apartments and Cottages on Townsend Road, where a minor noise increase of 3.3 dB was forecasted.

Table 5-6 shows the noise changes between the Do-Something design year and the Do-Minimum opening year at 410 receptors in the study area, categorised into the noise change bands following the magnitude impact ratings as required by DMRB. Noise contours indicating the long term change in noise levels in the design year are shown in Figure B-3 in Appendix B.

Table 5-6 Long Term Road Traffic Noise Impact (DS 2030 compared with DM 2016)




0.1 - 2.9 139 5 3 - 4.9 5 0 5 - 9.9 0 0

≥10 0 0

No Change = 0 0 1


0.1 - 2.9 248 12 3 - 4.9 0 0 5 - 9.9 0 0

≥10 0 0

Table 5-6 indicates that of the 410 receptors considered in this assessment, 405 were predicted a negligible impact or no change in the design year of the Development. A minor increase was forecasted at Chilton House Apartments and Cottages and 4 other residential receptors located on Townsend Road.

Effects on the Wider Area Road Network – DS 2030 vs DS 2016

The DS scenario in the design year gives rise to a number of minor adverse impacts in the wider road network and a smaller number of moderate ones. There are also a large number of minor beneficial changes forecast. Early indications are that the beneficial changes outweigh the adverse changes however the actual impact will depend on the locations of the changes and the numbers of affected receptors.

5.2.2. Night time assessment Table 5-7 presents the noise levels at all sensitive receptors categorised in terms of the DMRB long term noise change magnitude levels for night-time. Night-time noise levels have been calculated in the Noisemap


software from the 18 hour traffic flows based on Method 3 of the 2006 Defra/TRL report5. Night-time impacts are only reported where the predicted noise level is greater than 55 dB Lnight,outside in any scenario.

Facade noise contours indicating the absolute noise levels and the change in noise levels, at night-time, in the design year are shown in Figure B-4 and Figure B-5 respectively in Appendix B.

Only one receptor was predicted free-field noise levels at night exceeding 55 dB, which is a potential dwelling located near the southbound on-slip. A negligible decrease in noise was predicted at this receptor. This assessment is based on a simple assessment using a conversion factor from the 18 hour daytime traffic flows. Further investigation should be undertaken using hourly night-time traffic flows.

Table 5-7 Long Term Road Traffic Night Time Noise Impact



Increase in noise level, Lnight

0.1 - 2.9 0 0 3 - 4.9 0 0 5 - 9.9 0 0

≥10 0 0

No Change = 0 0 0

Decrease in noise level, Lnight

0.1 - 2.9 1 0 3 - 4.9 0 0 5 - 9.9 0 0

≥10 0 0

5.3. Assessment of permanent traffic induced vibration impacts It is stated in Annex A1.22 of DMRB that calculations or measurements of vibration at the foundations of typical buildings considered to be high risk may be taken if ground-borne vibration on existing routes is considered to be a potential problem. This includes locations where traffic is expected to pass very close to buildings.

At the time of writing, there are no known existing ground-borne vibration issues on existing routes in the study area, and a vibration assessment is therefore not considered necessary.

5 Defra/TRL/Casella Stanger (2006). Method for Converting the UK Road Traffic Noise Index LA10,18h to the EU Noise Indices for Road Noise Mapping”.


6. Construction Noise Assessment The following construction activities are likely to be required to complete the proposed alterations at the A34 Chilton Interchange:

Earthworks and road building for the north-facing slip roads, Earthworks to extend the restricted byway passing beneath the new north-facing northbound on-slip

road, Construction of two north-facing slip roads and a roundabout to accommodate each slip road, Retaining wall construction adjacent to the north-facing southbound on-slip road and the roundabout

close to the north-facing northbound on-slip road, and Construction of an under-bridge at the north-facing northbound slip road to accommodate the public

byway operating beneath it.

It is assumed that all of the construction works for this Development will take place during the day time. At the present time, an indicative construction programme and duration of works has not been established. It is assumed in this assessment that each of the three construction activities will take place separately without an overlap, and will take place during normal daytime working hours. Furthermore, it is also assumed that all of the plant required for an activity would be operating simultaneously in the same location.

In absence of a plant list provided by the construction contractor, indicative plant lists based on similar construction works for other projects have been formed to estimate the construction activity noise levels generated at Chilton Junction. Generic noise data for each activity has been taken from BS 5228, and used along with the prediction methodology. The acoustic data for the plant that is expected to be used during the construction period have been provided in Table 6-1, Table 6-2, and Table 6-3. It is assumed that the plant list for the construction of the under-bridge will be similar to that for the retaining wall provided in Table 6-3.

Table 6-1 Activity Noise Level - Earthworks

Plant BS 5228 reference

Quantity LAeq at 10m (dB)

On time (%)

Corrected LAeq (dB)

22T Excavator C.2.21 1 71.0 50 68.0 40T Dumper truck C.6.26 2 79.0 75 80.8 Delivery lorry C.2.30 1 79.0 25 73.0 Bomag/vibratory roller D.3.16 1 78.0 10 68.0 20T Dozer C.2.12 1 81.0 25 75.0 Activity noise level (LAeq, dB) 82.7


Table 6-2 Activity Noise Level - Road Construction



On time (%)

Corrected LAeq (dB)

Hiab C.4.53 1 77 25 71.0 Pick up C.6.21 1 80 25 74.0 Lorry delivery C.2.30 1 79 25 73.0 22T Excavator C.2.21 1 71 50 68.0 Compressor and pneumatic breaker

D.8.8 1 87 10 77.0

Asphalt spreader D.8.26 1 80 10 70.0 Activity noise level (LAeq, dB) 80.9

Table 6-3 Activity Noise Level - Retaining Wall or Under-bridge



On time (%)

Corrected LAeq (dB)

30T excavator C.2.16 1 75 50 72.0 Excavated material lorry tipper C.2.30 1 79 25 73.0 Crawler crane C.3.29 1 70 50 67.0 Handheld air tools D.8.8 1 87 25 81.0 Concrete pump C.3.26 1 75 50 72.0 Concrete mixer truck C.4.20 1 80 25 74.0 Water pump C.2.46 1 62 75 60.8 CFA piling rig C.12.42 1 83 50 80.0 40T dumper truck C.6.26 1 79 75 77.8 Compressor D.7.9 1 74 25 68.0 Generator C.6.39 1 65 50 62.0 Activity noise level (LAeq, dB) 85.8

The construction noise levels have been calculated at the closest noise-sensitive receptors to the Development, taking into account ground type, screening from nearby buildings, and distance from each construction activity. The results of these calculations are shown in Table 6-4, Table 6-5, and Table 6-6. In absence of baseline noise levels at the time of writing, it was assumed that the baseline daytime ambient noise level throughout the area was 55 dB(A) and that all of the receptors were classified as Category A receptors. This assumes a worst-case scenario where the potential for a significant effect is realised where the construction noise level exceeds 65 dB(A).

The plant list for retaining wall or under-bridge construction includes a continuous flight auger (CFA) piling rig. In general terms, piling is considered to have the potential to give rise to vibration impacts at buildings less than 20m from piling locations. Maps of the area indicate that all of the closest residential and commercial receptors are located at least 100m from the retaining wall and under-bridge construction sites, and therefore a vibration assessment is not required.



Table 6-4 Construction Noise Results for Earthworks

Receptor Baseline noise level (LAeq, dB)

BS 5228 Category

Distance to activity (m)

Ground type

Construction noise level (LAeq, dB)

BS 5228 Threshold

Value

Potential for a Significant

Effect? UKAEA 55 A 50 Soft 67.2 65 Yes 2 Manor Close 55 A 60 Soft 65.2 65 Yes 5 Manor Close 55 A 53 Soft 66.6 65 Yes 8 Manor Close 55 A 47 Soft 67.9 65 Yes 5 Limetrees 55 A 97 Soft 55.0 65 No 8 Limetrees 55 A 98 Soft 54.9 65 No 10 Limetrees 55 A 96 Soft 55.1 65 No Garden Centre 55 A 40 Soft 69.6 65 Yes White Road 55 A 128 Hard 55.6 65 No Chilton Primary School

55 A 250 Hard 49.7 65 No

Chilton House Apartments and Cottages

55 A 135 Hard 55.1 65 No

New Development 55 A 140 Hard 54.8 65 No Byway 55 A 7 Soft 85.8 60* No

* The 5 dB(A) Change method outlined in BS 5228 Annex E.3.3 is more appropriate for the assessment of construction noise impacts in public open spaces. If the pre-construction baseline noise level plus construction noise level exceeds the pre-construction baseline noise level by 5 dB(A), a potential significant effect is deemed to have occurred.

Table 6-4 shows that the a potential significant effect would be expected at noise sensitive receptors within 65m of earthworks. This mainly affects residential receptors at Manor Close, which overlook the construction of the new roundabout to accommodate the north-facing off-slip road. A potential significant effect was also predicted for UKAEA and a Garden Centre, both of which are non-residential receptors located close to Chilton Junction. A public byway, located within an AONB, will also experience a significant increase in noise close to the construction works, however, the byway will be closed for the duration of the construction works and will not impact human receptors using the Byway.



Table 6-5 Construction Noise Results for Road Construction


BS 5228 Category


Ground type


BS 5228 Threshold

Value


Effect? UKAEA 55 A 15 Soft 61.5 65 No 2 Manor Close 55 A 40 Soft 47.5 65 No 5 Manor Close 55 A 53 Soft 48.9 65 No 8 Manor Close 55 A 49 Soft 37.2 65 No 5 Limetrees 55 A 97 Soft 37.3 65 No 8 Limetrees 55 A 98 Soft 37.2 65 No 10 Limetrees 55 A 96 Soft 37.4 65 No Garden Centre 55 A 58 Soft 49.7 65 No White Road 55 A 200 Hard 34.0 65 No Chilton Primary School

55 A 350 Hard 29.1 65 No


55 A 135 Hard 37.4 65 No



Table 6-5 indicates that a significant effect would not be expected at any receptors during road construction. This includes the construction of the slip roads, the roundabouts, and any new access roads.



Table 6-6 Construction Noise Results for Retaining Wall


BS 5228 Category


Ground type


BS 5228 Threshold

Value


Effect? UKAEA 55 A 147 Soft 37.8 65 No 2 Manor Close 55 A 245 Soft 32.3 65 No 5 Manor Close 55 A 235 Soft 32.7 65 No 8 Manor Close 55 A 225 Soft 33.2 65 No 5 Limetrees 55 A 280 Soft 25.8 65 No 8 Limetrees 55 A 277 Soft 25.9 65 No 10 Limetrees 55 A 273 Soft 26.1 65 No Garden Centre 55 A 100 Soft 45.0 65 No White Road 55 A 250 Hard 32.0 65 No Chilton Primary School

55 A 335 Hard 29.5 65 No


55 A 310 Hard 35.2 65 No



Table 6-6 shows that construction noise arising from the construction of the retaining walls is not expected to cause a significant effect at residential and commercial receptors located in the study area. However, a significant effect is expected at sections of the public byway located close to the construction activity, which may affect ecological receptors. The byway will be closed during the construction works and will not affect the public’s enjoyment of the AONB during this time.

Construction noise levels during the construction of the under-bridge are assumed to be equivalent to the predicted noise levels for the retaining wall construction. It is evident from Table 6-6 that a potential significant effect is unlikely at receptors greater than 100m from the works. At the site of the new under-bridge, the nearest noise sensitive receptors are at UKAEA (230m) and 8 Manor Close (320m). On this basis, construction noise relating to the new under-bridge is not expected to cause a potential significant effect.



6.1. Construction Noise Mitigation To mitigate the significant effect arising from construction noise at Manor Close, it is recommended that a temporary noise barrier is installed for the duration of the construction works. A noise barrier is expected to mitigate construction noise levels by 5-10 dB, which would decrease the predicted noise levels at Manor Close below 65 dB(A) and reduce the potential for a significant effect to occur. For the noise barrier to be effective, it should be continuous, break line of sight with the receptor and must not contain any holes or gaps.

Good stakeholder relations are often the most effective way to manage potential noise impacts on site. Therefore, the Contractor ought to keep local residents and other receptors informed of the progress of the works, including when and where the noisiest activities will be taking place and how long they are expected to last. All noise complaints should be effectively recorded, investigated and addressed.

In addition, the Contractor ought to consider general good working practices including:

All vehicles and plant should be fitted with effective exhaust silencers which should be maintained in good and efficient working order.

All compressors and generators should be ‘sound reduced’ models fitted with properly lined and sealed acoustic covers which should be kept closed whenever the machines are in use.

All ancillary pneumatic percussive tools should be fitted with mufflers or suppressors as recommended by the manufacturers which should be kept in a good state of repair.

Machines in intermittent use should be shut down when not in use or where this is impracticable, throttled down to a minimum.

The site compound and static machines should be sited as far as is practicable from noise sensitive buildings.

Where practicable, plant with directional noise characteristics should be orientated to minimise noise at nearby properties.

Concrete mixers should not be cleaned by hammering the drums. When handling materials, care should be shown not to drop materials from excessive heights.

Even with appropriate mitigation in place it may not be possible to eliminate all noise impacts. However, best practice, considerate working hours as well as frequent and open communications with stakeholders will help to reduce the residual impact of construction noise.



7. Conclusions The assessment has identified a short-term minor adverse impact at four receptors as a result of the proposed Development at Chilton Junction (DS1 scenario). These receptors are UKAEA and a Garden Centre, both located close to Chilton Junction, and two residential receptors located immediately west of the Garden Centre. Noise mitigation, in the form of a noise barrier, may be required adjacent to the new roundabout connecting the northbound on-slip road to the A34 to reduce the road traffic noise levels at the residential receptors.

In the DS2 traffic scenario, which takes into account a number of other small road schemes within the wider area, a minor short-term adverse effect was forecast at UKAEA only. A minor benefit was identified to the west of the Development at receptors positioned in proximity to A4185 Newbury Road between Curie Avenue and Perimeter Road.

A long-term minor adverse impact was identified at 5 residential receptors a result of the Development at Chilton Junction. The affected receptors are located at Townsend Road and were predicted a minor increase in noise levels of 3.3 dB(A).

Initial indications for the wider area road network are that the Chilton Slips scheme, in isolation, would have minimal effect on roadside noise levels. When taking into account the Chilton Scheme in combination with other proposed small road schemes, the beneficial changes on the wider area road network are likely to outweigh the adverse changes in both the short and the long term; however this is subject to further investigation taking into account the locations of the affected routes and the numbers of properties affected in each scenario.

No long-term significant adverse impacts were predicted in the night time noise assessment, however, this is based on an indicative assessment using a conversion factor from the 18 hour daytime traffic flows. Further investigation should be undertaken using hourly night-time traffic flows.

The Vale of White Horse District Council informed Atkins that a plot of land opposite UKAEA may be released for a housing development in the future. Assuming that proposals for the housing development are approved, the noise contours produced in this assessment suggest that there will be minor to moderate adverse noise impact at the housing development in the short term and a negligible adverse to moderate adverse impact was predicted in the long term. The severity of the range of impacts in the short and the long term is dependent on the arrangement of the houses within the plot of land under consideration.

The Development is situated within an AONB, with a public byway intersecting Chilton Junction. Noise levels exceeding the threshold for a potentially significant effect were predicted at the sections of the public byway closest to earthworks and retaining wall construction. However, the public byway will be closed during the construction phase of the scheme which negates the necessity for screening specifically for the public byway.

During the construction phase of the Development, a potential temporary significant effect was predicted at residential receptors at Manor Close during earthworks associated with the new eastern roundabout to accommodate the north-facing off-slip road. The addition of a noise barrier to the southern perimeter of these works should be sufficient to remove the potential for a significant effect at Manor Close. However, best practice, considerate working hours as well as frequent and open communications with stakeholders will help to reduce the residual impact of construction noise.

Appendices



Appendix A. Maps of study area and sensitive receptors

Figure A-1 Map of study area

Contains Ordnance Survey data © Crown copyright and database right 2014

Ambulance and Fire Station

Sports Pitch Public Byway

Severn Road

Frome Road

Gemini Building, Fermi Avenue

Library Avenue



Figure A-2 Map of study area

Contains Ordnance Survey data © Crown copyright and database right 2014

UKAEA

Public Byway

Chilton Village Hall

Chilton Primary School

Garden Centre

Lower Road

5 Limetrees

2 Manor Close

8 Manor Close

5 Manor Close

Chilton Apartments and Cottages

8 Limetrees

10 Limetrees

The Paddock

White Road

Eastern Edge of New Development

Unspecified Receptor Near Southbound On-Slip



Appendix B. Noise contours This section presents noise contour maps indicating the changes in noise level between the Do Minimum 2016 scenario and each of the Do Something scenarios in the opening and design years.

Additional maps are presented to indicate receivers where Lnight noise levels are expected to exceed 55 dB Lnight, to fulfill the requirements of a DMRB Simple Assessment.



Figure B-1 DMRB Opening Year Noise Change Contours (DS1 data) at 4m Height Above Ground



Figure B-2 DMRB Opening Year Noise Change Contours (DS2 data) at 4m Height Above Ground



Figure B-3 DMRB Future Assessment Year Noise Change Contours at 4m Height Above Ground



Figure B-4 Future Assessment Year Noise Levels at Night (Lnight) at 4m Height Above Ground



Figure B-5 DMRB Future Assessment Year Night-Time Noise Change Contours at 4m Height Above Ground

© Atkins Ltd except where stated otherwise. The Atkins logo, ‘Carbon Critical Design’ and the strapline ‘Plan Design Enable’ are trademarks of Atkins Ltd.

Louise Morris Atkins Woodcote Grove Ashley Road Epsom KT18 5BW

[email protected] 01372 752791

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