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High Speed 2 Line: Chilterns

Question for Department for Transport

UIN 71490, tabled on 20 April 2017

To ask the Secretary of State for Transport, if he will list the reports and investigations that have taken place on the Chilterns Aquifer to establish the level of risk posed to the aquifer by the construction of High Speed 2.

Answered on

25 April 2017

There have been investigations and assessments carried out to understand the risks posed to the Chilterns Aquifer. This was assessed through the Environmental Impact Assessment process (2013) and reported in the Volume 2, 3 and 5 reports.

Since the Environmental Statement, a programme of ground investigation has been carried out in the Chilterns Aquifer which includes over 300 boreholes, 170 groundwater monitoring locations and 100 aquifer tests.

The ground investigation information has been used for several further local studies across the Colne Valley, the River Misbourne and Wendover. We will continue to work closely with both the Environment Agency and Affinity Water as the design progresses to ensure adequate steps are taken to protect the aquifer.

The specific completed reports and investigations that have taken place on the Chilterns aquifer are as follows:

Environmental Statement (2013)

As part of the Environmental Statement, impact assessments on the Chilterns Aquifer are presented in the Volume 2, 3 and 5 reports.

  • Volume 5 – Technical Appendices Water Resources Assessments for CFA6 to CFA11 (WR-002-006 to 11)
  • The results of the Volume 5 reports are summarised in the corresponding volume 2 reports for their community forum area.
  • Water resources: Route-wide appendix (WR-001-000)

Ground investigation of Chilterns Aquifer


Undertaken to date

Further planned




Groundwater level monitoring locations



Groundwater quality monitoring



Aquifer permeability tests



In addition to the above since the completion of the Environmental Statement we have completed a Technical Note: Wendover Springs Investigation (12 January 2017). Further studies are in progress regarding the River Misbourne and with Affinity Water.

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