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SCOTTISH EXECUTIVE CENTRAL RESEARCH UNIT

Environment Group Research ProgrammeResearch Findings No. 23

Monitoring and Mapping of Environmental Noise

Dr Bernadette Mckell, Steve Fisher, Nigel Jones, Jane Evans and Brian Stark
(Casella Stanger)

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Main Findings

• Within the study area, the organisations and agencies that will be responsible for providing data for noise map production and the directive requirements have been identified 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 solutions to overcome any barriers to data collection are suggested.
• 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 map consequently produced.
• A number of technical questions about the nature and type of systems set up to collect and collate the required data have been identified. These focus on issues about how features can be geographically or spatially represented within any model and what information about these features should be held.
• Much of the required data on road, rail and air sources was readily available, although availability, cost and interpolation issues inevitably arise at this early stage. A particular issue with data interpolation was found in relation to the data held on the airport in the study area.
• Much less information on ports and industrial sites is available and protocols to model such data need to be developed.

Noise Mapping

This research was 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 the Assessment and Management of Environmental noise. The research aim of this study was 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 was gathered for a 9 km2 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 surrounding road, rail, aircraft and sea ports to be examined.

The organisations and agencies that are likely to be responsible for providing data for noise map production under the directive requirements have been identified. 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 the report offers some 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 the Scottish Executive's Geographic Information Service were in a form which were readily input into the model although additional data had 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.

It became clear in the early stages of the study that the production of noise maps is as much about the acquisition, transfer, management and ownership of a number of disparate electronic geographic information (GI) databases as about technical acoustic issues.

Road sources

Throughout the study, the accepted UK prediction methodologies were used in determining what level of data detail to request from the attribute data providers. Both the Scottish Executive and the Local Authority were able to provide traffic flow data. Percentage HGV was 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. It is recommended that a protocol for describing HGV is 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 is though that it may be possible to obtain road level information from the road maintenance 'operating companies'.

In summary it was concluded that it would be possible to model road traffic noise with the data available.

Rail sources

Railtrack were able to provide all the information requested, except data on the various different track and track support structures, e.g. bridges. This would require a site survey.

As with road noise, it would be possible to model railway noise with the data available.

Airports

The aircraft data was not readily useable in the noise model as it required conversion to the grid locations used in the model. Funding for this data interpolation work was outwith the scope of the project. However, it is possible to state that, subject to such interpolation, it would have been possible to model aircraft noise with the data available.

Industrial and sea port sources

With regard to industrial noise, data on the location of Part A and Part B processes was available from SEPA; however no dedicated noise data in respect to these processes 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.

Noise mapping: data availability and handling

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 are given in chapter 6 of the report. 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 recommended 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 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.