Greenwich Trunk Main Phase Three: Barhale and Suez ice pigging lessons for engineers
Reviewed by Tom Sullivan
First reported on The Construction Index
30 Second Briefing
Thames Water has appointed Barhale to deliver Phase Three of the £17m Greenwich Trunk Main, installing the final 1km of ductile iron pipeline by open-cut from the Blackwall Lane roundabout to the O2 arena and connecting 350mm–800mm diameter sections to the existing 800mm main at Croon’s Hill. Barhale and specialist contractor Suez will commission the 4km main using ice pigging rather than swabbing and high-velocity flushing, saving about 1.8m litres of water and cutting required pits from 25 to six. The approach trims project costs by roughly £800,000, reduces carbon and brings forward commissioning of Phases Two and Three to May 2027.
Technical Brief
- Ice pigging fills the 350–800mm trunk main with ice slurry, then pushes it using water.
- The 4km Greenwich Trunk Main ties into an existing 800mm diameter main at Croon’s Hill.
- Phase One (2.7km) runs across Greenwich Park and was the park’s largest job since London 2012.
- Phase Two comprises an 80m section installed across the new Silvertown Tunnel corridor.
- Commissioning is sequenced with Phase One in Q4 2026, Phases Two and Three in May 2027.
- Ice pigging removes sediment and residues before final chlorination of all trunk main sections.
- The scheme is driven by increased network capacity demand from intensive developer growth on Greenwich Peninsula.
Our Take
Barhale’s £17m Greenwich Trunk Main award sits alongside multiple Thames Water schemes in our database (including Brent Cross and South Basingstoke under the AMP8 major projects framework), signalling that Barhale is becoming one of Thames Water’s core civils delivery partners in London and the South East.
Cutting commissioning pits from 25 to 6 through ice pigging on the Greenwich Trunk Main implies a substantial reduction in surface disruption across South London, which is strategically important given the project’s interface with dense urban areas around Greenwich Park and the Greenwich Peninsula.
The 1.8 million litres of water savings reported for this scheme align with a cluster of ‘Sustainability’-tagged UK water infrastructure pieces in our coverage, where utilities like Thames Water are under pressure to demonstrate tangible leakage and wastage reductions alongside capacity upgrades.
Prepared by collating external sources, AI-assisted tools, and Geomechanics.io’s proprietary mining database, then reviewed for technical accuracy & edited by our geotechnical team.
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