Background
Daguerre Point Dam was originally constructed in 1910 and rebuilt in 1964 following extensive flood damage to act as a barrier to reduce high sediment loads from moving downstream. Daguerre is currently used to facilitate water diversion for irrigation purposes but does not provide any additional benefits such as flood control, water storage or power generation. Daguerre is equipped with fish ladders but they do not meet modern fish passage design standards, and they are not effective in passing all species of concern over a full range of flows.
Englebright Dam was constructed in 1941 for the specific purpose of holding back debris generated by hydraulic mining. Englebright serves as the afterbay for New Bullards Reservoir hydropower facilities and the forebay for the Narrows 1 and 2 Powerhouses but does not provide any additional benefits such as water delivery or flood control. Since its construction, Englebright Dam has trapped ~23,000,000 cubic yards of mercury contaminated sediment, or roughly 25% of its original storage capacity.
Project
Previous assessment activities concluded that dam alterations or removal for fish passage were cost prohibitive because of the sediment and that there was no habitat for fish in the Yuba. The Sierra Fund is investigating sediment removal techniques with multiple benefits. Additionally, TSF is looking closely at salmonid holding habitat and caring capacity for the Yuba River to evaluate the extent of habitat available for salmonids. These efforts will inform the benefits of restoring habitat in the Yuba for threatened and endangered species and return a vital cultural life way to the river and First People.
Impact
Modification of Daguerre Point Dam and Englebright Dam to allow volitional upstream passage to previously unreachable habitat for anadromous fish would open up a minimum of 60 additional miles of habitat. In addition, the natural flow regime, natural sediment and nutrient regimes and reduced mercury exposure risks through fish consumption and reduced mercury methylation potential in the reservoir are all benefits of restoring longitudinal connectivity.
Next Steps
The Sierra Fund is working with partners to develop an approach for modifying Daguerre and Englebright which would allow for volitional fish passage, while maintaining the use of the facilities. Additionally, The Sierra Fund is developing a parallel approach to addressing barriers in the upper reaches of the Yuba Rivers such as Our House Dam on the Middle Yuba and Log Cabin Diversion Dam on Oregon Creek, a major tributary to the Middle Yuba.