In my blog Join up the dots and see what you get (posted 27 Jul 2016) I explained that it is only now, with the recent addition of an indication of the extent of the lowest observed adverse effect level (LOAEL) as determined by the maximum noise level from a single train pass-by (LAMax), that the operational noise maps published by HS2 Ltd indicate the true impact on health and wellbeing. That, you might think, would be bad enough, but the underlying implications cut much deeper into the essence of the HS2 design.
Simply, the reason why the LAMax LOAEL was not shown on the noise contour maps as originally published is, as I understand it, because the adoption of the LAMax LOAEL post-dated the publication of the Environmental Statement (ES). As far as I can tell, the first mention of the LAMax LOAEL came when Information Paper E20 was first published, which was some eight months after the ES (see footnote 1). The result of this is that you will search the ES in vain to find any reference to LOAEL expressed in terms of LAmax (see footnote 2).
It is true that you will find predicted values of LAMax for every assessment point in the tabulations in the Appendix SV-004-0xy series in ES Volume 5, but these are required because the ES employs LAMax as one of the parameters for the determination of the significant observed adverse effect level (SOAEL) threshold (see footnote 3): these maximum noise level predictions have not been utilised to determine if the assessment points will be at, or above, LOAEL.
The outcome of this important omission is that the evaluation of the acoustic impacts of the HS2 design, and consequent assessment of the need for mitigation, have been based upon too lenient criteria and are, subsequently, deficient; and I don’t think that I am being over-dramatic in making that claim.
A good illustration of what this means in practice was brought to the attention of the Lords HS2 Select Committee by Cllr Michael Burgun when he presented the petition of the Joint Parish Council for Eathorpe, Hunningham, Offchurch and Wappenbury (see footnote 4). Cllr Burgun complained that the “average noise maps used during all previous meetings” with HS2 Ltd had “created the impression that the village of Offchurch was effectively outside the affected area” (see footnote 5). One of the exhibits that he presented to the Committee, which I reproduce below, is the HS2 Ltd “average noise map” covering Offchurch village and surrounding area, to which Cllr Burgun and his colleagues have added a single red line near the bottom of the frame.
Cllr Burgun referred to this red line as “the 57dB free field peak noise approximate contour”: this corresponds to the 60dB façade level that HS2 Ltd has set as LOAEL night. Although the councillor accepted that this addition to the HS2 Ltd drawing was “an amateur attempt”, he was clear what it unequivocally demonstrated (see footnote 6):
“… the average grey contour of 40dB at night average noise has correctly or otherwise created the illusion that the village was outwith any noise effects of any consequence. The peak noise contour, accepting please, that it is approximate, indicates that Offchurch village sees peak noise in excess of the contour drawn.”
Cllr Burgun reinforced the message by then showing the Committee the tabulation reproduced below.
The councillor clarified that the tabulation includes “all of the noise receptors, including a couple outside our area on the road that proceeds towards Cubbington” and explained (see footnote 7):
“Any time that the day-time average goes over 50, we’ve made it red; every time the night-time average goes over 40, we’ve made it red; and every time the peak noise goes over 57, free field measurement, we’ve put it red.”
He concluded that it showed, “Quite a lot of red for our quiet rural greenbelt and conservation area to be subjected to” (see footnote 8). Indeed, whereas 16 of the 27 assessment locations exceed the 40dB LOAEL night equivalent continuous sound level, amounting to 59 per cent, that figure rises to 25, or 92 per cent, when the LAMax LOAEL threshold is employed.
Of course, what Cllr Burgun was demonstrating to the Lords Select Committee for Offchurch had already, as I reported in my blog A very noisy bird, part 1 (posted 22 Aug 2015), been shown to be true for Wendover and Berkswell to the Commons Select Committee, and, we can be sure, applies up and down the HS2 route.
(To be concluded …)
- According to the front cover of each volume, the original issue date of the Environmental Specification was November 2013 (actually 25thNovember 2013). The date printed on Information Paper E20 has been updated with each new version without, contrary to good practice in document control, an issue history being included in the document. However, the website that is a gateway for downloading the E-series of information papers lists the original issue date as 30th July 2014.
- See, for example, paragraph 1.5.41 of ES Volume 5 Appendix SV-001-000, where LOAEL is defined in terms of LpAeq
- See paragraph 1.5.26 of ES Volume 5 Appendix SV-001-000.
- The hearing may be viewed from the start of the video of the afternoon session of the HS2 Lords Select Committee held on Tuesday 19thJuly 2016.
- See paragraph 34 of the transcript of the afternoon session of the Lords HS2 Select Committee held on Tuesday 19thJuly 2016.
- See paragraph 35 of the transcript of the afternoon session of the Lords HS2 Select Committee held on Tuesday 19thJuly 2016.
- See paragraph 36 of the transcript of the afternoon session of the Lords HS2 Select Committee held on Tuesday 19thJuly 2016.
- See paragraph 37 of the transcript of the afternoon session of the Lords HS2 Select Committee held on Tuesday 19thJuly 2016.
Acknowledgement: I wish to thank Michael Burgun for providing me with copies of the two items from the evidence exhibits submitted to the Lords HS2 Select Committee by the Joint Parish Council for Eathorpe, Hunningham, Offchurch and Wappenbury.
Important Note: The record of the proceedings of the Lords HS2 Select Committee from which the quotes reproduced in this blog have been taken is an uncorrected transcript of evidence, which is not yet an approved formal record. Neither witnesses nor Members have had the opportunity to correct the record in such instances, and it may therefore be subject to changes being made in the light of any such corrections being requested.