Shasta & the Long-Term Operation Plan for the Central Valley
Achieving durability and equanimity for multiple needs
Preface
Within the Bureau of Reclamation's California-Great Basin Region operation of the Central Valley Project (CVP) is of the utmost importance – detailing how the network of dams, powerplants, and related facilities integrate within the world of California water.
The range of operating scenarios for the CVP is as wide as the project itself. The next iteration of the long-term operation plan will be the result of a marathon process of analysis, consultation and decision-making that has benefitted from the contributions of an unprecedented number of those directly and indirectly affected by the CVP.
While there’s an amazing number of components and considerations associated with operating the CVP, its purpose is virtually unchanged from the time the idea of conveying water from north to south emerged more than a century ago. That mission has grown increasingly complicated but water from the CVP continues to be a steady supply for cities, farms, refuges and the environment.
Water is a precious commodity, and California's tumultuous cycle of hydrologic feast-or-famine compels a rigorous, thoughtful and honest discussion of the challenges facing the CVP and finding workable and long-lasting solutions. Adopting a new operating plan provides the opportunity to become reacquainted with the many benefits the CVP provides and how it meets the many demands placed upon it.
For more background information:
Introduction
For more than 80 years, Reclamation has provided water and power to people, agriculture, and the environment even as managing the Central Valley Project becomes more challenging. The task often pivots on a hair’s breadth, with a slight margin for error and substantial consequences hanging in the balance.
Water quality and endangered species obligations significantly affect the dynamics of CVP operations each day. Reclamation’s long-term operation plan charts the course for moving water to where it’s needed – whether that means deliveries to water contractors or ensuring enough outflow for the Sacramento-San Joaquin Delta.
"The long-term operation plan is all of the Central Valley Project and the Delta facilities of the State Water Project, but this story is Shasta," said Dave Mooney, area manager for Reclamation's Bay-Delta office.
And that’s where the paradigm shift happens. The web of legal, statutory and regulatory requirements Reclamation adheres to is complicated, specialized and sometimes overlapping.
The reality is that Shasta is the straw that stirs the drink. Its relatively modest 4 million-plus acre-feet of storage helps steer the CVP’s adherence to the Endangered Species Act and the Bay-Delta Water Quality Control Plan . However, Reclamation experts stress that simply adjusting the knobs of water operations can’t be the only tool for the conservation and recovery of endangered fish.
“One of the lessons that we've learned through the Endangered Species Act consultations is that it takes many different organizations to ensure that the recovery of winter-run Chinook salmon will be successful,” said Josh Israel, who leads the science division in Reclamation’s Bay-Delta Office. “Science-led partnerships, where agency and interested parties' leaders and scientists learn from their actions together, can result in the resources, capacity and expertise to implement actions necessary for winter-run Chinook salmon recovery.”
Planning for climate extremes
Planning for CVP operations means considering all scenarios. Rim-full reservoirs in spring are a welcome sight. Half-empty reservoirs are a dire warning of crisis conditions. The skewing of California’s already fickle climate is evident.
The growing collection of evidence illustrates the growing extremity of California’s climate, with hotter and drier droughts bookended with wetter and stormier periods in the winter. The ramifications are important as the downstream temperatures that Reclamation manages are ultimately determined by the volume and temperature of inflows.
Derya Sumer, modeling division manager, Reclamation’s Bay-Delta Office.
Shifts in the magnitude and timing of reservoir inflow, temperature, and sea level “have large implications” on Reclamation operations below Shasta Dam and across the Central Valley Project, according to Derya Sumer, manager of the modeling division in Reclamation’s Bay-Delta Office.
“These factors are anticipated to intensify due to climate change and we need to understand how these changes will continue to affect our operation of Shasta and the entire CVP system,” she said.
Climate change effects are becoming more pronounced, and Reclamation is responding. When the 2019 long-term operation plan was unveiled, climate signals were documented and accepted in the scientific literature. Since that time, the world’s oceans are storing less additional heat , hastening the realization of climate change effects.
The increasing variability compels Reclamation to view the long-term operation plan through a lens of climate conditions that are increasingly extreme and unpredictable.
“Now that we've started to see the effects of climate change, it makes sense to plan for it and try to incorporate it as our baseline scenario so that we understand how operations are going to change,” said Reclamation hydrologist Drew Loney.
Drew Loney, water resources engineer, discusses climate change impacts affecting the Central Valley Project.
“We wanted to make sure that we were getting the best estimate from the models that are good at representing California's climate.”
Already realized changes in temperatures and precipitation are corrected within the historical data to arrive at what’s called the initial detrending of historical hydrology.
“We adjust the historic runoff to make it look like what would happen under current climate conditions,” said Loney. “If we were to experience the rain and snow from 1930 today, what would we expect that to look like?”
California regularly exhibits periods of heavy rain and snow coupled with multiyear droughts that are challenging to forecasters. Parsing climate change-fueled episodes is a continuing exercise.
“Natural variability is the $64,000 question because you're always trying to tease out what is natural variability versus what is a climate change-driven event,” said Loney. “For the data we put in, a lot of it is driven by that natural variability.”
The Preferred Alternative
The product of extensive consultation and review, Reclamation’s range of alternatives for the long-term operation of the CVP are the result of contributions by the many consulting agencies and the collective path they see for how the CVP should operate.
What’s been arrived at are consensus-driven actions between Reclamation and its state and federal consultation partners for the operation of the CVP within the confines of the federal Endangered Species Act and the state’s public trust provisions . It means increasing the ability of the CVP to meet a chilly 53.5-degree water temperature at or downstream of the Clear Creek confluence even during multiple years of drought. This has consequences to water supply, other rivers, and other species.
Clear Creek
The long-term operation of the CVP is broad but the largest lever is Shasta Reservoir. It’s the cornerstone of the CVP but its operation is not so simple as instream flows, flood management, power generation and water supply. Retaining sufficient cold water is an overarching necessity. During extreme drought periods, the stakes are vital for winter-run Chinook salmon.
“If we don’t provide cold enough water, the eggs that they spawn don’t survive. The mortality rate is really high when the water is too warm.”
If the water needed for diversions, flow and water quality must be stored to maintain a cold-water pool, the water needed to meet those other demands must come from other sources. Groundwater and other reservoirs also strain under the duress of drought. It's further complicated because of the need to release water from Shasta to maintain space for flood management.
When water is retained in the lake that could have been delivered, and then that water must be released for flood control, there is a cost that did not benefit the following year’s temperature management season, said Mooney.
“We 'spill' [for flood control] most years, so the new proposed action is a matter of degree to which we balance costs today and future drought risk,” he said.
Water spills from Shasta Dam
Operating the CVP means coordinating with Sacramento River water users to find the balance between storage and release that meets downstream demands. It's a carefully coordinated process involving other CVP reservoirs such as Folsom and Trinity to help preserve storage in Shasta.
It means holding water in the winter and spring and reducing deliveries for contractors, instream flow needs and Delta water quality. It’s a process of storage, release and diversion that hinges on the ability of Shasta’s temperature control device to manage use of the cold-water pool.
In place for almost 30 years, the massive temperature control device structure is a critical part of Shasta that enables Reclamation to meet its regulatory requirements while maximizing power production at the dam. Installing the device “was as important as completing the dam as far as our operations today go,” said Bader.
The temperature control device
Don Bader, area manager Northern California Area Office
Drought and Water Conservation Actions Agreement
The consequences of drought devastated Sacramento Valley farmers and wildlife refuges in 2022. The extremely dry conditions meant that water service contractors received 0% of their CVP allocation, while Sacramento River Settlement Contractors and wildlife refuges only received 18% of their contract quantities.
Averting a similar disaster in the future meant finding a progressive way forward. In the northern Sacramento Valley, with its wealth of agricultural landscape, a pending agreement with the Sacramento River Settlement Contractors aims to keep as much land as possible in production while acknowledging the reality of regulatory compliance.
Sacramento Valley Farmland
Individually and collectively, the Sacramento River Settlement Contractors hold some of the oldest water rights in California, dating to the late 19th century. As much as 2 million acre-feet of contract water is available, to irrigate 440,000 acres bordering the Sacramento River and its tributaries in the 150 miles between the cities of Redding and Sacramento.
That water availability is reduced to 1.5 million acre-feet when Shasta reservoir is designated as a critical year for inflow. Under the Drought and Water Conservation Actions Agreement with the Settlement Contractors, additional shortages would occur in the driest of critical years, enabling Reclamation to better operate under its junior water right and manage river temperatures downstream of Shasta Dam.
Kristen Hiatt, natural resources specialist, Reclamation's Bay-Delta Office
Kristen Hiatt, natural resources specialist in Reclamation’s Bay-Delta Office, said the proposed agreement responds to the need for Reclamation’s management of the CVP in drought years by preserving cold water storage in Shasta Reservoir to assist in protecting winter-run Chinook salmon against decline and future drought risks.
“Water temperature management is very challenging in the driest of dry years and minimal carryover results in little drought protection in subsequent years if they continue to be dry."
The agreement calls for the Settlement Contractors to be compensated for the additional shortage, which will occur when the system is extremely stressed and experiencing critical drought conditions. They will respond to the reduced water supply by idling and shifting crops, pumping groundwater and applying water conservation measures.
Giant garter snake
To the extent possible, the agreement is designed to help protect and preserve habitat for the giant garter snake . Listed as threatened by the Endangered Species Act, they are one of the largest garter snake species at more than 5 feet. They are native only to the Central Valley and are found on natural, managed and agricultural wetlands.
The agreement designates some of the compensation for drought resiliency projects that aim to strengthen the resilience of the Settlement Contractors’ water systems and long-term water delivery capabilities, Hiatt said.
During the initial 10-year phase of the agreement, water diversions by Settlement Contractors would be reduced by as much as 500,000 acre-feet should forecasted Shasta inflow be less than 2.5 million acre-feet and storage in the reservoir is less than 3.3 million acre-feet at the end of April. It's also applicable should storage be less than 2 million acre-feet at the end of September.
In the second 10-year phase, the Settlement Contractors would reduce diversions by no more than 100,000 acre-feet each year under similar criteria. Hydrology is fickle and modeling shows that the likelihood of these delivery reductions is infrequent and could happen not at all or as many as four times in a decade, similar to the drought of 1924 to 1933.
Don Bransford
Don Bransford, who grows rice, almonds and prunes in Colusa, said the plan represents the successful collaboration between the Sacramento River Settlement Contractors, Reclamation and federal and state regulators to not only provide water for needed protections for fish and terrestrial species, but also to provide certainty to contractors as to maximum reductions in water supply during challenging drought years.
“These collaborative efforts are extremely important, provide needed certainty and will hopefully provide a framework for future drought resiliency actions. It bears emphasis, however, that these actions present significant hardships to our landowners, our local economy, and the environment where we live and work. We must ensure we are using the best science, data and restoration programs to improve our fishery and inform our decision-making, because temperature management alone will not protect and recover the fishery."
Real-Time Operations and Species Recovery
California’s native fish species face a multitude of challenges to their continued existence. A highly modified environment, loss of habitat and food sources and competition from non-native species are just a few of the stressors that push fish such as the winter-run Chinook salmon to the brink of extinction.
The dire nature of the problem means Reclamation and its partners are already “greatly intervening” with actions designed to promote species recovery, Israel said. Reclamation is committed to maintaining Shasta’s temperature control device and funding the improvements to Livingston Stone National Fish Hatchery . Other aspects of recovery work are spearheaded by federal and state fish and wildlife agencies.
Livingston Stone National Fish Hatchery
It's well-known that adjusted water operations can’t be the only tool for conservation and recovery. Finding a successful outcome to the plight of salmon means acknowledging the multitude of stressors facing the fish and finding the means of helping them through all their life stages.
“For us to have an effect on winter-run Chinook salmon and the ecosystem that they rely on, we need many partners,” said Israel. “We can’t do it alone. It’s not isolated to actions around operations but involves actions that improve habitat, hatchery practices and increase the species survival.”
Josh Israel, science division manager, Reclamation's Bay-Delta Office
CVP actions are an important metric but only a piece of the greater puzzle. Jon Ambrose, branch chief with NOAA Fisheries, said the agency’s 2014 recovery plan for winter-run Chinook salmon makes it clear that recovery can’t be achieved until at least three independent populations are established.
Because one of those populations is downstream of Shasta, “ensuring the necessary conditions are in place to maintain the population downstream of Shasta is very important, including conditions provided by the cold-water pool in Shasta reservoir,” said Ambrose. However, winter-run Chinook “will remain at perpetual risk” until significant additional actions are undertaken to reintroduce them to their ancestral habitats upstream of the dam, such as into the McCloud River.
McCloud River
A beginning, not an end
Reclamation’s long-term operation of the Central Valley Project is a detailed, complex and layered process that significantly revolves on Shasta Reservoir and how it’s operated for multiple purposes.
“Shasta is the kingpin of California’s water. How well Shasta is doing drives the entire state’s success for water.”
Implementation is underway on many actions, including those at Livingston Stone National Fish Hatchery, where a substantial funding allocation will provide much-needed improvements. The work will take time but promise lies ahead. “We are at the very beginning of planning,” said Reclamation’s Rupert. “There is a long road ahead.”
A key aspect moving forward is adaptive management – the proven tool that is the bellwether of successful water operations and species protection. Indispensable to the process are the contributions from the wide universe of people whose knowledge and experience are the foundation of a balanced and well-informed document.
Reclamation’s long-term operation of the CVP is the product of extensive analysis, consultation and deliberation, but it does not proceed in a silo. There’s too much at stake and the contributions from partner agencies are key to making the plan work. The work toward a revamped operation plan is reaching a critical stage . Now, it’s time for the many voices of the public to be heard.
Shasta Dam and Lake
Reclamation’s draft EIS is available here . Written comments can be sent to: sha-mpr-bdo@usbr.gov by close of business Sept. 9, 2024. For more information about the public meetings or the draft EIS, visit www.usbr.gov/mp/bdo/lto/index.html
For more information follow the Bureau of Reclamation with the links below.
Partner Agencies