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MONITORING AND MAPPING OF ENVIRONMENTAL NOISE
EXECUTIVE SUMMARY
- STANGER have been commissioned to undertake a scoping study to consider some of the issues surrounding the collection and handling of data associated with the mapping requirements likely to result from the proposed EC Directive on Environmental noise. The research aim of this study is to provide the Scottish Executive with information on the issues surrounding the availability and collection of data involved in the production of noise maps that will have to be produced in order to meet the expected requirements of the proposed EC Directive on Environmental Noise.
- In discussion with the Scottish Executive a small study area was identified and data has been gathered for a 9 km 2 study area in Renfrewshire. The area selected reflected the desire by the Scottish Executive to have a sufficiently large and complex area to enable the important data issues such as road, rail, aircraft and sea ports to be examined.
- STANGER have identified the organisations and agencies that will be responsible for providing data for noise map production and the directive requirements. The form of data requested is outlined and the extent to which the data required is available from these bodies has been reported. Where the collection of data is likely to be problematic this has also been identified and STANGER have suggested solutions to overcome any barriers to data collection. The limitations of the data supplied in relation to the prediction methodologies employed are discussed along with the implications of the accuracy of data on the validity and relevance of any model consequently produced.
- The modelling software used for the noise map was ' Cadna'. The mapping products supplied by SEGIS were in a form which were readily input into the model although additional data was required to be collected through a site survey, e.g. building heights and road level and speed limits, railway cuttings. Editing of the files was therefore required; specifically joining together the dxf files, putting heights onto buildings, 'cleaning' the roads data (identifying road segments), inputting bridges flyovers and cuttings.
- STANGER requested a level of data detail from the attribute data providers determined by the accepted UK prediction methodologies. Both the Scottish Executive and the Local Authority were able to provide traffic flow data (although some data is still to be collated by the local authority). Percentage HGV were derived from vehicle length classes in the case of the M8 which is probably underestimating the percentage HGV. For local authority data the percentage HGV was derived from count data. Protocol for describing HGV requires to be produced to ensure consistency of approach. Average traffic flow speeds were not available and this information was obtained through site survey. The Scottish Executive was able to provide texture depth information but not surface type. Renfrewshire Council were able to provide both road surface type and texture depth information as they had undertaken a site survey. It may be possible to obtain road level information from the road maintenance 'operating companies'.
- In summary it was possible to model road traffic noise with the data available.
- Railtrack were able to provide all information requested except data on the various different track and track support structures, e.g. bridges. This would require a site survey. It was possible to model railway noise with the data available.
- The aircraft data was not readily useable in the noise model as it required conversion to the grid locations used in the model. This work was outwith the scope of the project. However, it is possible to state that with an additional cost to the CAA or further conversion work by STANGER it would have been possible to model aircraft noise.
- With regard to industrial noise limited data on the location of Part A and Part B processes was available from SEPA, however no noise data was available. This would require development of a noise protocol. Both development of a protocol and site measurement were outwith the scope of the project. Consequently, at this point in time it is not possible to model industrial noise with the information available. Extensive site work would be required.
- Similarly assessment of Sea Ports operations would also require a site survey to identify noise sources and subsequent modelling using on site measurements or database sources noise levels. This was outwith the scope of the project and so port noise cannot at this stage be modelled without extensive site work.
- Therefore it has been concluded that there are limitations in the data currently available, e.g. industrial sources, seaports, road traffic speed, building heights, road levels, information on structures such as bridges cuttings, flyovers.
- Extensive recommendations for further research have been given in chapter 6. This chapter also considers issues such as the mechanism for compiling noise maps with regards to data availability and licence issues. This will be dictated by whether the mapping is carried out centrally by the Scottish Executive or by local authorities either directly or indirectly by mapping contractors. If the latter option is adopted the question of obtaining data either from SEGIS under licence or directly from OS may arise. In addition it has been recommenced that noise modelling software compliance standards and the use of products such as OS MasterMap be given further consideration.
- Finally, while the cost of 'data cleaning' for the pilot area is reasonably quantifiable, scaling up for a larger study area is outwith the scope of this project. It is acknowledged that the method employed in the study area could be is unworkable when at a smaller scale (i.e. larger area) due to the amount of data cleansing to be done. It is therefore recommended that consideration is given to scaling up the costs of obtaining input data for agglomerations in Scotland.
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