Drought in California is pushing many to pursue options for additional water storage in the region, and the Nevada Irrigation District is proposing construction of a new reservoir, the Centennial Reservoir Project.
NID says existing water use exceeds its current storage and supply capabilities and it needs to enhance its capacity to collect and conserve water.
In April 2016, directors of the irrigation district approved a $1.3 million contract with AECOM for a third phase of geotechnical studies of the proposed Centennial Reservoir site. AECOM previously completed the first two phases of study.
AECOM will conduct further geotechnical investigation, provide conceptual design and engineering reports, develop construction cost estimates and schedules, and provide environmental support and project management.
Centennial Reservoir, on the Bear River, has been in planning since 2014, Nevada Irrigation District says. However, the vision for this project dates back to 1926, NID says, with creation of a comprehensive plan for the region’s water supply system.
The reservoir would hold up to 11,000 acre-feet of water and be located below NID’s Rollins Reservoir and below its Combie Reservoir. The dam will be about 275 feet tall.
Initial studies narrowed seven potential sites to two, and five potential types of dams were studied, with roller-compacted concrete and concrete-faced rockfill seen as most favorable.
A report on the KQED Science website says the project possibly includes a “new hydroelectric unit at Rollins Reservoir, for which the district already has a federal permit. The district would use revenues from electricity sales to help offset construction costs.”
NID hopes to begin construction of the reservoir in 2021 and complete the project in 2023. The district says planning and building the project will cost $200 million to $300 million, potentially funded through state water bonds and such other sources as a local bond issue and recreational funds. Construction of the project is anticipated to create hundreds of jobs each year.
The Centennial Reservoir website says a draft environmental impact report/National Environmental Policy Act was due for completion in December 2016 but it is unclear if that was completed on schedule.
NID owns eight hydroelectric plants with a total capacity of 82.2 MW.