Brine fields add ‘Spicy’ geotechnical problems to HS2 route

One of the big issues to come out of Wednesday’s debate in Westminster Hall was the major problems caused by geotechnical issues on the route chosen by Hs2 Ltd.  We’ve raised this before – see here and here.  So it is good to see it raised in Parliament.  Here is what Antoinette Sandwich (MP for Eddisbury) and Esther McVey (Tatton) had to say:

Antoinette Sandbach

It is a pleasure to serve under your chairmanship, Mr McCabe. I am pleased to have secured this debate on a matter of immense importance to me and my constituents. If phase 2b is to go ahead, it is vital that it be done properly. At such a high cost to the taxpayer—£55.7 billion—and with budgets having risen significantly since High Speed 2 was first announced, the route must be designed so as to avoid unnecessary cost to the taxpayer and with minimum disruption to the communities that it affects.

The proposed route of HS2 through my constituency of Eddisbury will not only cause significant environmental damage and noise disruption to many areas, but come at a particularly high cost to the taxpayer because of the unique geotechnical challenges of routing HS2 through an area of current and historical salt mining and across land with a long history of significant subsidence risk. HS2’s route through Eddisbury must be looked at again, and the serious and valid concerns raised by independent experts, academics and local people need to be taken into account to find a route that works better both for the local communities and for the taxpayer….

…I also wish to raise the decision last year to realign the route through Eddisbury 800 metres to the west, and the concerns that have been raised about taking it through an area with a greater amount of wet rockhead—unstable ground liable to subsidence as a result of salt. HS2’s decision to move the route came about because the original 2013 proposed route went through the area where the UK’s strategic gas reserves are stored. It was of course practical to move the route away from the gas reserves, but moving it 800 metres to the west has caused other problems, because it still goes through an area with geotechnical challenges that are not easy to engineer around and where there will be a significant cost to the communities and the taxpayer.

TerraConsult Ltd produced an independent geotechnical report on the proposed change of route and concluded that there would be an increase of 11% in the route length over wet rockhead. HS2’s lead ground engineer has called the ground conditions in the Cheshire salt area “spicy”, referring to the engineering challenges of building a high-speed railway line in that area, and HS2’s own consultant, Wardell Armstrong, recognises the risks of building HS2 through Eddisbury in its report on salt-related ground instability.

The Government must recognise the risks in the area and move the route away entirely. Alarmingly, before making route choice proposals, HS2 had not done any detailed ground surveys for use as a baseline to track ground movement. As far as I am aware, those surveys have still not been carried out.

The engineering challenges require significantly increased height and length of the embankments and viaducts—up to 26 metres. There will be two additional crossings of the Trent and Mersey canal, one at the location of previous subsidence at Billinge. That comes at an estimated additional cost to the taxpayer of £750 million and significantly increases the noise and visual damage for communities.

The route alternatives set out in the TerraConsult report should be looked at and given serious consideration. The decision document issued in July, following the recent consultation, does not contain any reference to the TerraConsult report or the points made in it. Was it considered in detail before a decision on the route in Eddisbury was made? If it was, why has HS2 to date failed to disclose the AECOM report, to which the Minister has referred in correspondence, despite numerous requests to do so?….

Ms Esther McVey (Tatton) (Con)

I congratulate my hon. Friend and neighbour on securing this important debate. I endorse all the points that she is making, in particular those about safety, security, suitability and cost. My constituency, too, is full of brine fields and wells where salt has dissolved and been pumped out, which creates craters underground. Ros Todhunter, a geologist who lives in Lostock Green in my constituency, has also discussed land movement. Railway engineers talk about permitted movement of 5 mm, but we could be looking at 0.5 metres. As my hon. Friend has said, there should be discussions with people who know the land well—their families have farmed this land for hundreds of years and they know about problems under the earth that, I am afraid, the Government have so far not looked into.

Antoinette Sandbach
I am grateful for my right hon. Friend’s intervention, because I have met Ros Todhunter and am aware that Ministers and HS2 have had high-level technical reports from her explaining some of the real difficulties in my right hon. Friend’s constituency and mine. A deep worry is that HS2 does not seem to be disclosing the appropriate level of technical reports to experts who are meant to be giving expert opinion highlighting proper concerns which are right to express at this stage in advance of a serious engineering project. One such expert is one of the most eminent professors in the field of salt subsidence, who wrote to the Secretary of State more than 18 months ago to emphasise that ground-level surveys ought to be started now, so that HS2 can identify subsidence and problem areas.

I say to the Minister that it would be extremely beneficial for MPs across the House who are affected by HS2 to be regularly updated by the engineering team on the detailed design of the route, to ensure that there is an appropriate level of scrutiny and to allow valuable input in the process. Reports regarding route decisions and sift documents ought to be shared with Members as a matter of course, not kept from us. There simply has to be better engagement, and with an acute awareness and understanding of local issues.

From Hansard.

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