APPENDIX C - ENVIRONMENTAL APPRAISAL METHODOLOGY
APPENDIX C - ENVIRONMENTAL APPRAISAL METHODOLOGY
Environmental Topic |
Methodology |
Comment |
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Air Quality |
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Cultural Heritage |
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HS would be happy with any sub-option which had no more impact on Orrock House than the route agreed in 1996. AC would look unfavourably on any sub-option that would sever Menie House from the gatehouse |
Disruption due to Construction |
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Property estimates are included in Appendix B: Environmental Appraisal Table. The counts include properties common to all routes Covered in appropriate sections Sub-option’s 1, 2 and 3 may require additional vehicle movement to dispose of excess cut material. Sub-option 5 provides best earthworks balance thus reducing vehicular movements. |
Ecology and Nature Conservation |
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Comments from SNH the same for all sub-options |
Landscape Effects |
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Walk-over focussed on the differences between the route sub-options |
Land Use and Agriculture |
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None Sub-option 3 in close proximity to one property, ‘Seaview’ No parks or recreation grounds affected, however informal footpaths and bridleways may be affected. There are no major water bodies or rivers, the majority of the watercourses within the study area are small burns and drain eastwards towards the coast. Those in the north drain to the Ythan which is designated for its European nature conservation interests |
Traffic Noise and Vibration |
An assessment was undertaken in general accordance with DMRB Stage 2. Given the similarities of the proposed sub-options and the project specifics (e.g. common junction designs and common start and finish points for the scheme), the adopted assessment method was based on DMRB Stage 2 but tailored to highlight the differences in noise impact that would result from each sub-option and facilitate direct comparison. The following methodology was adopted:
1. the numbers of residential receptors within each individual distance band (0 to 100m, 100 to 200m and 200 to 300m) and the total number of receptors within 300m, for each sub-option and the baseline scenario. 2. the number of receptors particularly sensitive to noise within each distance band and within 300m 3. the number of receptors subject to an increase of greater than 1 dB, a decrease of greater than 1 dB and a neutral change of less than 1 dB
In addition to the above, an assessment in full accordance with DMRB Stage 2would require the following:
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Comments on Adopted Methodology: DMRB Stage 2 requires that 100, 200 and 300m distance bands are drawn from the ‘centre line’. The guidance does not provide advice on whether the bands should consider the centre of just the primary route section, or all affected local routes. To highlight differences in the sub-options, it was considered most robust to include all new routes and realigned routes that were not common between the sub-options. The DMRB states that property numbers can be estimated. In the interests of accuracy, property numbers were based on detailed counts. The DMRB does not require that especially sensitive receptors properties are categorised by distance. This was completed to add extra clarity. The Stage 2 assessment requires that a sample of representative receptors is adopted, but for robustness, noise predictions were carried out at all receptors within the identified distance bands. These tabulated changes were considered appropriate for comparing directly the relative merits of the various sub-options. Comments on DMRB Stage 2 assessment components not included in the adopted methodology As noise level changes were calculated and tabulated for every individual receptor, the identification of noise level changes at sample receptors was considered not to provide any additional information to that already considered in the appraisal. It is anticipated that the distances at which noise level changes from the sub-options would be discernible would depend upon the local topography and distance between the current and proposed route alignments. These factors would vary across the length of each sub-option and would relate directly to the numbers of properties subject to noise increases and decreases. Therefore, this part of the assessment was considered not to provide any additional information to that already considered in the appraisal. The Stage 2 vibration assessment is based upon the predicted LA10 18 hour noise levels, which have been used to determine the preferred sub-option. In addition, each of the route options would result in fewer receptors within the 40m distance criteria for the assessment than the baseline scenario. Consequently, should airborne vibration be a problem at the present time, each of the sub-options is likely to result similar improvements. Therefore this assessment was considered not to be critical to the selection of the preferred sub-option. Regardless of whether ground-borne vibration is an issue with the current alignment, all of the sub-options would result in fewer receptors in close proximity to the A90. Therefore this assessment was considered not to be critical in the identification of the preferred sub-option. The Stage II assessment requires a statement be made on the significance of noise impacts on local people and sensitive locations in particular. To ensure a robust assessment, the preferred sub-option was selected based on the numbers of individual receptors subject to noise level increases, decreases and neutral changes. The significance statement requires consideration be given to noise level changes on the existing network. In the case of this development, each sub-option had the same junction alignments at the start and finish points and a similar junction towards the centre. As such, it was anticipated that similar noise level changes would results on the local network for each sub-options. Where the sub-options are significantly different from each other, the nature of the surrounding area is rural. As such, it was considered unlikely that any sub-option would require significantly different levels of noise mitigation. |
Pedestrians, Cyclists, Equestrians and Community Effects |
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See Figure 2.6 See Appendix B Foveran Primary School Route See Appendix B. no formal routes identified. |
Vehicle Travellers |
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Water Quality And Drainage |
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All are described in Section 2.6.10 and 5.12 All sub-options cross the same major water courses including those which drain to the Ythan Estuary. Spill risk and pollution risk appraisals have therefore not been carried out for Stage 2 as it was not considered that these would be a useful decision tool. Detailed assessments, including calculations will be carried out for the preferred route for the Environmental Statement Further detailed mitigation will be included in the Environmental Statement. Commitments to best practice and design considered to be adequate at Stage 2. |
Geology and Soils |
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See Section 2.6.11 and 5.13 No contaminated land has been identified within the study area. See Section 2.6.11 and 5.13 |
Policies and Planning |
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