The primary purpose of the Authority, as stated in the agreement, is to pursue the development and construction of the Sites Reservoir Project, which has long been viewed as an ideal location for additional off-stream storage to provide direct and real benefits to instream flows, the Delta ecosystem, and water supply.
The Authority is governed by a Board of Directors that collaborates with other groups in the region interested in the construction of Sites Reservoir Project.
The project was also selected to apply for a $2.2 billion Water Infrastructure Finance and Innovation Act (WIFIA) loan through the Environmental Protection Agency.
[18] For example, Sites can be operated in coordination with Shasta Lake to preserve and enhance cold water for endangered salmon in the Sacramento River or to increase fresh-water flow into the Delta during drier periods to assist with salinity management.
[19] Storing water in Sites Reservoir during times when there is a lot of flow in the Sacramento River for use during times with the flows are low, including during drought periods, is part of the statewide strategy for adapting to changing climate conditions and to return much needed flexibility to the statewide water management system.
Water from the Sacramento River is diverted at the existing Red Bluff Pumping Plant, owned by the United States Bureau of Reclamation and operated by the Tehama-Colusa Canal Authority, and at the Hamilton City Pump Station, owned and operated by the Glenn-Colusa Irrigation District.
Water diverted at the Red Bluff Pumping Plant, would enter the Tehama-Colusa Canal and be conveyed down to Funks Reservoir.
After water is diverted at the Hamilton City Pump Station, it would enter Glenn-Colusa Irrigation District’s Main Canal and be conveyed down to the new Terminal Regulating Reservoir.
From 2017 to 2023, the Sites Project Authority and the Bureau of Reclamation completed a review process for potential environmental impacts and mitigation measures.
The project was certified by Governor Newsom under Senate Bill 149, making it eligible for streamlined judicial review under the California Environmental Quality Act (CEQA).
(The Sacramento River's flows include water allocated from the Trinity and other northern tributaries, despite harm to salmon runs in source watersheds.)
[23] According to "Final Feasibility Report" submitted by the Bureau of Reclamation in December 2020 : "A substantial portion of the project’s water would be specifically dedicated to environmental uses, helping to improve conditions for Delta smelt, preserving the cold-water pool in Lake Shasta to support salmon development, spawning and rearing, and providing a reliable water supply to improve the habitat for migratory birds and other native species" .
The environment is to be the single largest user of water stored in Sites Reservoir, managed and distributed by federal and state natural resource agencies.
By delivering water to CVP contractors from Sites Reservoir, Reclamation may maintain supply in Shasta Lake to support habitat for salmonid spawning, incubation, rearing, and migration.
The possible additional water supply in Shasta Lake can then be allocated during real-time management scenarios for several uses (e.g., coldwater pool maintenance, spring pulse or fall pulse flow events, increased stability in fall flows) that may provide enhanced anadromous fish benefits.
The Sites Project Authority is to implement best management practices to minimize any potential water quality impacts associated with facility operations and maintenance.
According to a 2023 report by Tell The Dam Truth[28] and Friends of the River,[29] funded by Patagonia, Inc.,[30] the Sites Project as designed is predicted to emit approximately 362,000 metric tons of CO2e/year averaged at the 75th percentile over an assumed 100-year life, including decommissioning (demolition/draining).