Question to the Department for Transport:

To ask Her Majesty's Government what independent assessment has been made of the management of the (1) water flow, (2) settlement, and (3) distribution, of the cut-and-cover tunnel on HS2 Phase One at Wendover; and whether construction of the tunnel will require additional land take.

Thorough assessments of a range of potential impacts from the HS2 Phase One green tunnel at Wendover continue to be made and assured by HS2 Ltd’s contractors. These utilise approaches such as numerical groundwater modelling, fluvial modelling and purpose-designed pumping tests in order to provide the most accurate information about water movement in this area and any potential for impact from the construction of the railway.

These assessments, and the ongoing liaison with independent experts from the Environment Agency (with respect to water and flood risks), the Canal and River Trust (with respect to the Grand Union Canal) and Natural England (with respect to Weston Turville Site of Special Scientific Interest), will continue to inform the detailed design of the railway and requirements for monitoring and mitigation. Works involving water courses, groundwater and/or flood risks are then subject to independent approval by the Environment Agency.

There is no further land outside of HS2 Phase One Act limits needed for construction of the Wendover green tunnel.