Blackford Pumping Station

The brief

Affinity Water called us in to Blackford Pumping Station in Harefield, in the north-west London borough of Hillingdon. Blackford at the time was one of Affinity’s strategic groundwater sources, abstracting from the Mid-Chilterns chalk aquifer and feeding drinking water into the supply network for customers across the Colne Valley and south Hertfordshire. The job required multiple under-pressure drilling operations on pipework on the pumping station site.

Our approach

Under-pressure drilling is how you make a controlled tapping into a live main without taking it out of service. A drilling machine mounts to the outside of the pipe, cuts through the pipe wall while pressure is contained inside the equipment, and leaves you with a clean bore through which fittings, instruments, or further pipework can be connected to the main. The main itself never depressurises, the water keeps flowing, and downstream customers see nothing change.

On a site like a pumping station — where any loss of flow has an immediate operational consequence for abstraction, treatment, and network supply — under-pressure drilling is usually the only sensible technique. Lucas and Kris carried out the drillings on site.

Outcome

Drillings completed, pumping station stayed in operation, supply into the network uninterrupted. See our under-pressure drilling capability page for how the technique works across different contexts. The service context sits under water mains repair and maintenance for water companies.