Yes, but what about …?

The new document HS2 London to West Midlands EIA Scope and Methodology Report (here) claims, in paragraph 1.4.4 on page 3, that it “outlines the approach to the consideration of significant effects and their mitigation to be employed in the EIA”. So I hoped when I started reading this document that it would outline plans to tackle all of those issues that had been dropped into the “too difficult” basket when the Appraisal of Sustainability was written. Unsurprisingly, I opted to use airborne noise as my test of whether the document had grasped this particular nettle. Armed with my list of unresolved issues on noise, I checked the contents of chapter 13 of HS2 London to West Midlands EIA Scope and Methodology Report.

The first thing that I checked for was confirmation that the failure to provide the noise contour maps that we had been promised for the AoS by the then Transport Secretary – something that I had moaned about in my blog Pass me the map (posted 30 Jun 2011) – would be put right by the environmental impact assessment (EIA). I was pleased to see that the document acknowledged, in paragraph 13.3.10 on page 115, that this had been an issue raised by the public consultation. The document presents, in Table 25 on page 119, a “semantic scale” by which the magnitude of airborne noise impacts from train operations will be “quantified”, but provides no clue as to how these impacts will be presented. So we still don’t know whether noise contour maps will be provided.

Another issue that I would like to have seen properly addressed in HS2 London to West Midlands EIA Scope and Methodology Report is the admission in paragraph 5.6.9 on page 46 in Appendix 5.4 to the Appraisal of Sustainability Main Report (here) that the CRN calculation method “would need to be adapted” to make it suitable for use at speeds over 300 kph. I raised this issue in my blogs Trust me, I’m an acoustic engineer (posted 4 Jul 2011) and Doing things by the book (posted 15 Dec 2011).

Now you might think that I’m being a real fusspot about this, because we are told in paragraph 13.3.19 on page 117 of HS2 London to West Midlands EIA Scope and Methodology Report that:

“The [calculation] method has been further refined for HS2 to allow for aerodynamic sound sources at speeds over 300 kph.”

But, that is all it says. Well thanks for that HS2 Ltd; I don’t suppose that you would like to be a little more forthcoming would you? It would be nice to have some information on how you have cracked this problem in the year or so since the AoS was written. You don’t expect us just to take your word for it, do you?

And, whilst we are on the subject of the calculations, what about the assumed 3 dB reduction in train sound emission levels, which I discussed in some detail in my blog Perhaps you were right all along, perhaps not (posted 25 Nov 2011)? This is acknowledged as a consultation issue in HS2 London to West Midlands EIA Scope and Methodology Report and in paragraph 7.2.4 on pages 26 and 27 of Review of HS2 London to West Midlands Appraisal of Sustainability (here) we are promised:

“In common with all input assumptions, the train noise level will be revisited and checked for suitability as the input to the more detailed EIA, should the project be taken forward.”

Again, I can find no commitment to undertake this work within the pages of HS2 London to West Midlands EIA Scope and Methodology Report and of course there is absolutely no mention of the need to increase the train sound emission level to compensate for any deterioration in wheel/track roughness in operational conditions (refer to my blog It could be a bumpy ride, which was posted on 24 Oct 2011).

Finally, there is the not insignificant question of the feasibility and effectiveness of noise mitigation measures, including the design of noise barriers. On the specific question of the impact of aerodynamic noise sources high up on the train, for example the pantograph, we are told in paragraph 7.2.5 on page 27 of Review of HS2 London to West Midlands Appraisal of Sustainability that this “does need to be considered”. We are also promised in that paragraph that the effects of this noise mechanism “will be reviewed at the time of the EIA”.

On the more general aspects of noise mitigation, paragraph 6.3.6 on page 50 of Appendix 5.4 to the AoS says:

 “The way in which noise would eventually be mitigated would depend on various considerations, such as engineering feasibility and effectiveness, and may use any of the techniques set out in Section 2, either independently or in combination, and these would be developed further as part of the EIA should the scheme be progressed.”

So what does it say on this topic in HS2 London to West Midlands EIA Scope and Methodology Report? Well, paragraph 13.3.10 on page 115, does acknowledge that the effects of pantograph noise was an issue that was raised by the public consultation. Aside from this however, the document is totally silent on this topic.

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