Yuba Water Agency has expanded recovery operations at its damaged New Colgate Powerhouse in California, with large-scale sediment removal, road reconstruction and hillside stabilisation works now under way following February’s penstock rupture.
The latest update marks a shift from emergency response into longer-term restoration activity at the 340MW hydropower facility on the North Yuba River near Dobbins. The powerhouse has remained offline since 13 February, when a 14ft diameter penstock ruptured above the site, releasing around 400 acre-feet of water and causing extensive erosion and infrastructure damage.
Yuba Water said work is progressing on multiple fronts, including repairs to Lake Francis Road, sediment excavation within the river corridor and restoration of systems inside the powerhouse itself. Crews have already removed significant volumes of mud and debris from the powerhouse deck, where deposits reached more than 13ft deep in some locations. Approximately 11,000 cubic yards of material have been cleared from around the facility so far.
The utility is also preparing for a major in-river sediment removal campaign expected to begin this month. Current estimates indicate roughly 49,000 cubic yards of sediment upstream of the powerhouse and another 11,000 cubic yards downstream must be removed after hillside erosion during the rupture event.
Road access restoration is continuing in parallel. Yuba County contractor Nordic Industries is carrying out phased reconstruction of damaged sections of Lake Francis Road to re-establish safe access for investigation and rebuilding works. The road remains closed to the public beyond the final residential property.
Yuba Water said forensic engineers are continuing to investigate the cause of the penstock failure, with findings expected in autumn 2026. Early-stage planning and contracting for penstock reconstruction are already under way to accelerate the eventual rebuild programme once the investigation is complete.
The outage at New Colgate, one of California’s largest hydroelectric plants, is expected to continue for at least several years while repairs and reconstruction proceed.
