The Yuba Water Agency has issued a progress update on recovery efforts at its New Colgate Powerhouse in northern California, US, after the penstock rupture that forced the facility offline two month ago.
As previously reported, the 13 February incident released approximately 493,000 cubic metres of water down a hillside above the North Yuba River near Dobbins, California, causing extensive erosion and damage to the powerhouse, switchyards and access infrastructure, including Lake Francis Road. The facility remains out of service and is expected to be offline for several years.
Yuba Water said it is continuing to work with forensic engineers to determine the cause of the rupture, while in parallel advancing early-stage planning and contracting for the reconstruction of the penstock. This approach is intended to allow design work to begin as soon as the root cause has been identified.
On the ground, efforts to restore access to the site are progressing, with repairs to Lake Francis Road under way in phases. Initial work is focused on enabling access for utility vehicles, followed by heavier vehicle use and eventual reopening, although the road remains closed to the public beyond the last residence. At the same time, stabilisation of the damaged hillside above the powerhouse is ongoing to support both investigative work and future reconstruction.
Clearing the large volumes of debris generated by the incident remains a central challenge. At the powerhouse, crews are removing more than 8,400 cubic metres of sediment from the deck, where deposits reached depths of over 4 metres in places, while cleaning and restoration continues inside the facility, which avoided complete inundation. In the river system, work is also under way to remove an estimated 37,500 cubic metres of sediment upstream and a further 8,400 cubic metres downstream, with operations designed to limit environmental impacts.
The agency added that it continues to closely monitor conditions in the North Yuba River and downstream reaches as recovery progresses. While a timeline for returning the New Colgate Powerhouse to service has not been finalised, the update underlines the scale of the restoration effort and the long-term nature of the recovery following the February failure.
