Question to the Department for Environment, Food and Rural Affairs:

To ask His Majesty's Government, further to the Written Answer by Lord Benyon on 10 November (HL2965), which stated that "this discharge is made to surface waters rather than groundwater, greatly reducing the potential risk to the drinking water aquifer", whether this means that there is still some risk from the water being (1) reused in HS2 operations, including reinsertion to the aquifer at the tunnel boring operation, and (2) discharged to the water environment in a roadside ditch which is a winter born chalk stream directly above the principal aquifer.

Water is not discharged into the aquifer during tunnel boring operations. The roadside ditch is an artificial (i.e. man-made) drainage channel, not a winterbourne chalk stream. A quantitative risk assessment has been caried out for both surface water and groundwater impacts for discharge to the roadside ditch and the risk assessment showed the discharge was, given the controls on the permit, acceptable and not liable to cause pollution to either water receptor.