Question to the Department for Transport:

To ask His Majesty's Government what monitoring and safeguards are in place to protect aquatic ecosystems and local drinking water sources from chemical waste resulting from the construction of HS2, in particular in the Colne Valley and the Chiltern aquifer.

Comprehensive monitoring, in compliance with Environment Agency and water company standards and practices, is undertaken by HS2 Ltd’s supply chain in the vicinity of all HS2 construction activities. All of the monitoring data is subsequently shared and reviewed regularly with the Environment Agency, and for the Colne Valley area, with Affinity Water.

No adverse effects on groundwater or surface water ecosystems have been detected to date during construction of the Colne Valley Viaduct or Chilterns Tunnels, or from other construction activities across the wider Chalk aquifer through which HS2 passes. Monitoring will continue into the post-construction phase to confirm that there are no residual or developing water related issues.