Skip to main page content
View In Your Area map

Update on Herlwyn Avenue groundwater monitoring well

Work item: HS2-EW-SCS-Ph1-Ar-So-S2-OTH-1-27/06/23_1

Work Item Summary

Project Phase
Phase 1
Region
Hillingdon
Worksite Name
South Ruislip
Contractor
SCS JV
Type of works
Ground water monitoring
Estimated Start Date
26/06/2023
Estimated End Date
27/06/2023

What we are doing

Groundwater monitoring well incident
On the evenings of 26 and 27 June sandy water made its way up to the road surface on Herlwyn Avenue near to the junction with Roxburn Way (see map overleaf). We attended and cleaned up the area affected and have remained in the area to continue monitoring.

The sandy water is a mix of water, sand and air, and is safe. The water made its way up to the road surface via one of our groundwater monitoring wells when compressed air was used in a controlled way while the Tunnel Boring Machine (TBM) was undergoing normal maintenance. During this process, air can travel some distance, especially through permeable layers of the ground and come to the surface through a pathway such as an open monitoring well.

Our engagement team will in Herlwyn Avenue near to the junction with Roxburn Way for the rest of this week to answer any questions you might have.

Download information relating to these works

Find out more about

If you have a question about HS2 or our works, please contact our HS2 Helpdesk team on 08081 434 434 or email [email protected]