New Colgate Powerhouse Failure: SYRCL Tracks Water Quality and Salmon Impacts on Yuba River

On February 13, 2026, a catastrophic failure occurred at Yuba County Water Agency’s New Colgate Powerhouse during routine testing of a newly installed section of pipe, releasing approximately 400 acre-feet of water in a sudden flood that destroyed much of the facility and sent massive amounts of sediment into the Yuba River upstream of Englebright Reservoir. While the immediate crisis has passed, SYRCL is monitoring water quality impacts and long-term implications for the watershed.

On Saturday February 14th, approximately 18 hours after the penstock pipe failure at the Colgate Powerhouse, SYRCL’s Watershed Science Staff began collecting water quality samples to track the impacts of the ruptured pipe and associated landslide on downstream water quality. Samples were collected at Rice’s Crossing, just downstream of the incident, and at Bridgeport as a control site on the South Yuba, that was unaffected by the incident. We sampled for a suite of parameters including dissolved oxygen, temperature, pH, conductivity, and turbidity. Most of the parameters were within normal range, except for turbidity, which was significantly elevated. Turbidity is a measure of cloudiness of the water and serves as a proxy for suspended sediments; it is measured in NTUs or Nephelometric Turbidity Units.

Immediately following the event, turbidity levels were 59.5 NTUs at Rice’s Crossing, compared to 1.21 NTUs at the Bridgeport control site. With the help of volunteers, we were able to continue tracking turbidity at both sites, documenting elevated turbidity levels at Rice’s Crossing for a 6-day period, during which turbidity peaked around 67 NTUs on February 19th. By February 20th, on the tail end of the storm, turbidity levels at the control site at Bridgeport were 25 NTUs, while Rice’s Crossing had dropped to 7 NTUs. This finding indicated that the turbidity plume associated with the Colgate Powerhouse incident had moved through the Rice’s Crossing area, and that the elevated turbidity at Bridgeport was the result of natural storm-related runoff.

Meanwhile, SYRCL staff, concerned about the potential impacts to spring- and fall-run Chinook salmon, began to track water quality downstream of Englebright Dam, knowing that the turbidity plume would be moving in that direction. From Feb 18th- Feb 26th, SYRCL documented a 9-day period of elevated turbidity (between 31 and 99 NTUs) in the lower Yuba River below Englebright Dam.

While salmonids are resilient to short-lived turbidity spikes typically associated with natural disturbances such as storm or small landslide events, prolonged turbidity over 20 NTUs is known to negatively impact salmonids, detrimentally affecting feeding behaviors and resulting in poor health and sometimes death. SYRCL will continue to collaborate with partners at CDFW to monitor the health of aquatic species in response to prolonged turbidity levels.

Notably, SYRCL was the first on the scene documenting the tragic death of hundreds of salmon fry that were stranded in the lower Yuba in response to the sudden reduction in water levels that occurred as part of the incident, but prior to the arrival of the turbidity plume below Englebright. It is important to recognize that observations made by SYRCL staff represent site-scale evidence of juvenile salmonid mortality; however, because SYRCL only visited two discrete locations on the lower Yuba River, it is realistic to assume that this event actually resulted in the mortality of thousands of juvenile salmonids across the 24 river miles of the lower Yuba.

With the exposed hillslopes and potential for wet weather, we expect sedimentation could continue to be an issue, contributing to elevated turbidity levels and negative impacts to the ecosystem.

SYRCL will continue to track water quality during any upcoming storm events and will conduct snorkel surveys in collaboration with our partners as part of our restoration efforts in the lower Yuba to track how elevated turbidity is impacting salmon and other aquatic species.