Sites Reservoir is a potential new offstream reservoir that would be located about 78 miles northwest of Sacramento at the eastern foothills of the California Coast Range. Proposed by the California Department of Water Resources (DWR), Sites Reservoir would harness winter flood flows from the Sacramento River, divert the water upstream and pump it into a deep, 14,000-acre reservoir formed in the Antelope Valley. The valley now is used for cattle grazing.
The reservoir would be operated as part of California’s State Water Project (SWP). Water would arrive to the reservoir via the existing Tehama-Colusa and Glenn-Colusa canals, as well as a new pumping station on the Sacramento River. The water would then be released into the Sacramento River, augmenting natural flows and releases from other reservoirs.
Proponents say they favor the Sites location because it is not on a major river so it wouldn’t directly affect fish migration. Critics say diversions for the reservoir could take more than 60 percent of the Sacramento River flows at given times, with potentially significant impacts on the river’s riparian and aquatic ecosystems and the many fish and wildlife species that depend on those ecosystems.
The total reservoir capacity would be between 1.27 and 1.81 million acre-feet (by comparison Folsom Reservoir fed by the American River has a 1 million acre-feet capacity). The estimated water yield would be between 470,000 to 640,000 acre-feet per year, depending on yearly rainfall and environmental regulations, according to DWR. (One acre-foot of water is 325,851 gallons – enough water to cover one acre of land at one foot deep and meet the annual needs of two urban households.)
In addition to water storage, Sites Reservoir would be operated as a hydroelectric plant, helping in the generation of “power peaking” electricity for the Northern California grid by typically running only when there is a high demand — known as peak demand — for electric power.
Sites Reservoir is projected to cost between $2.3 billion and $3.2 billion, with annual operating costs between $10 million and $21 million, according to DWR.
It would provide economic benefits of between $248.8 million to $276.2 million per year, based on a 2013 Bureau of Reclamation (Reclamation) study.
The Sites proposal first emerged as part of the second stage of the SWP in the 1980s. The first stage comprised of Oroville Dam, the California Aqueduct and the associated hydroelectric plants and pumping stations. All this infrastructure was built during the 1960s to mid-1980s to provide an annual water yield of 2.23 million acre-feet.
SWP Stage II included Sites Reservoir along with a peripheral canal to divert water around the Delta and southward, and various other projects that would feature Northern California river diversions.
Renewed interest in the Sites Reservoir project has been linked to diminished water supply and delivery shortfalls due to drought, Delta pumping restrictions, population growth and climate change in California. North of Delta storage.
Sites Reservoir – officially referred to in studies by DWR and Reclamation as the North-of-Delta Offstream Storage Project (NODOS) – is planned to improve water supply reliability during drought periods when operated in conjunction with existing reservoirs. In all, the primary objectives are:
- Improve water supply reliability for agricultural, urban, and environmental uses
- Increase survival of anadromous and endemic fish populations
- Improve environmental and drinking water quality in the Delta
- Provide flexible hydropower generation to support integration of renewable energy sources
Where is Sites?
Sites, a small community in Colusa County in Northern California, is surrounded by rolling hills and set in a basin of grasslands used primarily for grazing cattle. The town was named for John Sites, a pioneer rancher in the late 19th century. Although no township exists today, the community of a handful of families and ranchers still maintain a proud heritage.
And, even though a reservoir amassing 14,000 acres would inundate the basin, most of the residents support the water storage proposal.
If the reservoir were to be built, the surrounding foothills would provide a natural barrier to the basin and facilitate the flooding of the long and narrow Antelope Valley, the 14,000-acre reservoir would be fortified by several dams. The main dams, Sites and Golden Gate, would be built across Stone Corral and Funks Creeks. Sites Dam, the larger of the two would stand about 310 feet high. Six smaller saddle dikes would hold in the north end of the lake, according to Reclamation.
Sites Joint Power Authority Board
The Sites Joint Power Authority Board is comprised of members representing water districts that have expressed interest in purchasing at least 20,000 acre-feet of water a year if the project is built. Those include: Colusa County Water District, Glenn County, Reclamation District 108, Colusa County, Glenn-Colusa Irrigation District, Maxwell Irrigation District, Orland-Artois Water District, Proberta Water District, Tehama-Colusa Canal Authority, Westside Water District and Yolo County Flood Control and Conservation Board.
The challenge is to find investors for a project that will offer water at a steep price tag, estimated to reach $500-$700 an acre-foot. Proponents admit it is an expensive investment, yet in 40-50 years, when the building financing has been repaid, those prices would be viable, they say. Also, during periods of drought, when water becomes scarce and costs increase dramatically, having a part of the water supply from Sites becomes attractive.
In September of 2015, the organization hired its first general manager Jim Watson, who is a former general manger for special projects for the Westlands Water District.