Should California Build Sites Reservoir?
As torrential rain has led parts of California to flush enormous quantities of water out to sea, many are wishing we had built the storage we voted for in 2014. But is that still the right approach?
With more than 2 months left of California’s rainy season, 5 of our 16 main reservoirs are more than 75% full. The Sacramento-San Joaquin Delta which acts as a hub for the Sacramento and San Joaquin rivers is flushing 95% of the incoming water out to the ocean through the San Francisco Bay. At the same time, the US Drought Monitor finds that 92% of the state is still in moderate or severe drought.
The unfortunate fact - especially for those who have suffered during these storms - is that California still needs more precipitation - a lot more.
When we find ourselves inundated with rain and hoping for much more - as we do every 4-5 years - Californians begin to ask: How can we store as much water as possible to hold us over during the dry years? This was the question voters had in mind in 2014 when they voted by a 2-to-1 margin to approve Proposition 1, which authorized $7.1B of bond funding for water projects.
One water storage project to surface in the aftermath of Proposition 1 is the Sites Reservoir. Sites Reservoir is an offstream reservoir that will capture excess water from the Sacramento River following major storms and save it for drier periods. The Sites Reservoir Project would be located in the western Sacramento Valley, by the town of Maxwell.
Sites Reservoir is not a new idea or even a 2014 idea. The California Department of Water Resources first proposed the idea in the 1950s, but it was abandoned in the 1980s as building dams in the West fell out of popular opinion. However, the passage of Prop 1 and the extreme 2012-2016 drought, breathed fresh life into the project.
Progress has been slow over the last 10 years, but the project passed some key milestones last year. Jerry Brown, executive director of the Sites Project Authority, is optimistic:
“We’ve definitely turned the corner and we have a nice tailwind at our back.”
The current project timeline has construction starting in late 2024 and operations beginning in early 2030.
Despite this progress, the project is meeting some significant and expected resistance.
Argument in Brief
Should California build Sites Reservoir?
Sites Reservoir will increase water for Californians significantly
It increases the flexibility and resilience of the state’s 2 water projects
Voters already approved financing for it
There are more cost-effective ways to increase water supply
California should build Sites Reservoir. It could store a meaningful amount of water and several analyses suggest that there is enough water in the Sacramento River to meaningfully fill it. There are legitimate environmental concerns, but these can mostly, if not entirely, be mitigated if Sacramento River flows north of Sites and flows into the Delta remain sufficiently high. Meeting these criteria and still filling the reservoir seem possible.
Groundwater storage may be the more cost-effective option, but a portfolio approach that embraces multiple forms of storage designed to collect and distribute different sources of water seem necessary to compensate for the projected 10% reduction in water supply in California’s future. Finally, we can’t wait the 15-20 years we would need to start this process over. Sites has been through a rigorous process over the last 10 years and it’s a year away from breaking ground. Let’s get it over the finish line.
Sites Reservoir will increase water for Californians significantly
For Sites Reservoir to meaningfully improve California’s water supply, it must be big enough to store a meaningful amount of water, and then it must be consistently full enough to deliver meaningful amounts of water. Sites Reservoir is expected to be a 1.5 million acre-foot (MAF) reservoir. As the state’s 7th largest reservoir, it would increase Nothern California’s water storage capacity by ~15%.
This is a meaningful amount of storage, but could we fill it?
We likely could this winter:
“Were Sites a reality today, it would be absorbing excess flow from the Sacramento River, banking water for when it would be needed in the future.”
The Sites Authority Project estimates it would have diverted 120,000 acre-feet of water into its reservoir in just 2 weeks this month.
But we don’t get these types of storms every year. Jeffrey Mount, a senior fellow at the Public Policy Institute of California’s Water Policy Center, argues excess river flow is an unreliable supply:
“Storms like this (current bout) just don’t come that often so you can’t always expect to fill your storage. What you want is reliable supply and this (type of storage) is not very reliable. You don’t know when you’re going to fill it.”
While this year’s rainfall has been exceptionally high, we do have reasonably consistent cycles of wet and dry years. The project’s original Environmental Impact Report estimated that Sites would receive an average of 500,000 acre-feet of water per year (a third of its capacity). Yet, the California State Water Resources Board doesn’t think we’ll be able to fill it:
“In a letter sent out by state regulators Friday, project officials were told that their application for a water right is incomplete because they failed to show that there’s sufficient flow to draw from in the Sacramento River.”
An analysis by the California Globe suggests the opposite:
“...if one-fifth of the Sacramento River’s flow upstream at Colusa had been diverted, and only during the seven mostly dry months from October 2021 through April 2022, the massive 1.5 million acre foot Sites Reservoir could have been filled nearly half way to capacity. In just one season, during a drought.”
Governor Newsom seems to agree:
“We did some analysis of those big flows that came in November and December of last year, and if we had the conveyance and the tools to capture that storm water, it’s the equivalent of those seven projects [7 storage projects totaling 2.77 MAF] that I just noted that take decades to build in terms of stored capacity.”
A robust analysis by the Public Policy Institute of California (PPIC) made a similar point back in 2017:
“The state should also more consistently track water that exceeds water demands and diversion capacity (“uncaptured water”), which can provide significant benefits for water users and ecosystems… During most years and on most rivers—even during droughts—there are periods when river flows exceed either the capacity of existing storage and diversion facilities or the combined demands for water diversions, system water, and ecosystem water.”
PPIC calculated uncaptured water flowing through the Delta between 1980 and 2016:
“Not surprisingly, uncaptured water is the most variable category of Delta water uses. It averaged 11.3 maf over the 1980–2016 period, with a low of 221,000 acre-feet in 1990, during an extended drought, and a maximum of over 64 maf in 1983, the wettest year in the sample.”
Sites Reservoir is 1.5 MAF and in the average year, 11.3 MAF of uncaptured water flows through the Delta.
It increases the flexibility and resilience of the state’s 2 water projects
The state’s 2 water projects link much of Northern California’s water in a complex system of dams and pipes. This can mean that diverting water into added storage capacity means less water for other parts of the system. Would Sites have to steal from other already empty reservoirs to fill itself?
Importantly, no. As an offstream or off-river reservoir, it does not dam up an existing river. Instead, it diverts water from the Sacramento River when water levels exceed a certain level through a series of pipes and canals to the reservoir. This suggests that filling Sites won’t involve taking water from waterways or storage facilities that are already lacking.
In fact, in a letter to the California Water Commission, US Senator Dianne Feinstein suggested that Sites would actually benefit other elements of the state’s water system:
“Sites Reservoir would allow reoperation of California's water infrastructure in numerous beneficial ways.”
The Sites Reservoir Project notes that this is a distinct benefit of Sites relative to other reservoirs in California:
“By operating in conjunction with other California reservoirs, Sites Reservoir substantially increases water supply flexibility, reliability, and resiliency in drier years. Sites Reservoir is the only proposed storage facility in the State of California that will help with statewide operational effectiveness of the State Water Project and Central Valley Project.”
There are a few specific ways that Sites can benefit the overall water system:
Making early water releases on behalf of northern reservoirs so that those reservoirs can store their water longer
Increasing the resilience of the water supply by relying on storm-related runoff rather than spring snowmelt
Maximizing capture of flood flows to minimize regional flooding
Skipping traditional winter flood control releases that other reservoirs, like Shasta and Oroville, are required to make, enabling Sites to hold onto its water longer
Enabling lower-cost replenishing of groundwater storage in the region
Mike Wade, executive director of the California Farm Water Coalition, says:
“They are the facilities of tomorrow that give us flexibility in managing the resource that we have today.”
Voters already approved financing for it
As noted earlier, 67% of Californians voted in favor of Proposition 1, which authorized bond funding for water projects and specifically water storage projects.
The authorized bond funding was designated for the following uses, with $2.7B allocated to dams and groundwater storage:
Specifically, the funds for new water storage had the following stipulations:
“The bond includes $2.7 billion to pay up to half of the cost of new water storage projects, including dams and projects that replenish groundwater. This funding could only be used to cover costs related to the “public benefits” associated with water storage projects, including restoring habitats, improving water quality, reducing damage from floods, responding to emergencies, and improving recreation.”
This funding still hasn’t been used yet:
“Nearly 10 years later, none of the major storage projects, which include new and expanded reservoirs, has gotten off the ground. The seven dedicated storage projects funded by voter-approved Proposition 1 remain in various stages of planning… ”
It may be slow, but the California Water Commission has approved $875M for Sites Reservoir. The Sites Project Authority says it has lined up the remaining funds for the $4B+ project, including over $214M in federal funds through the Bureau of Reclamation.
Voters deserve to see this money spent on water storage projects - or be given the opportunity to vote again to reallocate those funds. This doesn’t mean that these funds must be used to fund Sites Reservoir. Of the 6 other projects approved for Proposition 1 funding, 4 are for groundwater storage projects.
It will harm the environment and wildlife
Unlike most reservoirs, Sites Reservoir scores several points on the environmental scorecard on the basis of its design alone. It avoids damming up any river and only diverting water from the Sacramento River when the flow is higher than necessary for prior water diversions and the environment.
And yet, the Natural Resources Defense Council (NRDC) still actively opposes it. The NRDC’s senior director of the nature program, Kate Poole, explains their opposition:
“Building more storage generally means taking more water from the environment, and scientific reports have shown that California should significantly reduce water diversions from the Delta watershed to protect the environment, fisheries and water quality.”
The NRDC isn’t alone either. A petition against Sites started by the group, Save California Salmon, last year has obtained over 55,000 signatures. It argues that:
“[The Sites proposal] does not include protections for the Trinity River or Upper Sacramento River salmon or for the Tribes and fishermen that depend on them despite the fact it will lower flows and impact water quality some years.”
When the Sites Project Authority first submitted its Environmental Impact Report (EIR) in 2017, a number of groups, including the California Department of Fish and Wildlife shared concerns:
“The document’s disclosure and analysis of impacts to aquatic species is of particular concern to the Department, including an insufficient analysis of the impacts of increased diversions that would occur during Chinook salmon migration periods, smelt analyses that do not appear to reflect proposed Project operations and potential reductions in Delta outflow, and a lack of analysis of potential entrainment and impingement of green sturgeon and white sturgeon at Project intake facilitates.”
The Sites Project Authority submitted an updated EIR in November 2021 after trying to address initial concerns:
“The Project operations have been modified substantially over the last two years to be more protective of the environment. These modifications have reduced the Project diversions from the Sacramento River substantially (almost in half) as compared to the criteria proposed in 2017.”
However, the belief that Sites Reservoir will divert too much water from the Sacramento River remains the foundation of most concerns, with some opponents arguing that Sites could take more than 60% of the Sacramento River leading to a variety of harms:
Reduced salmon and other fish populations
Degraded Delta ecosystem, harming a variety of plants and animals
Release of low-quality water back into the Sacramento from Sites
Harmed northern water systems (Trinity River)
Reduced river flows could harm the salmon populations:
“In the upper Sacramento River, numerous studies have shown that the survival of juvenile salmon migrating downstream depends on adequate river flows, with survival of these salmon decreasing dramatically as flows decrease.”
As a result, NRDC says that the Sacramento River must have flows greater than 15,000 cubic feet per second before Sites can divert water into the reservoir.
Sites will also reduce flows downstream, thereby reducing the Delta outflow, which could impact fish species there:
“For salmon, peer reviewed studies have demonstrated that reducing Sacramento River flows causes the survival of salmon migrating through the Delta to decrease when flows are less than ~35,000 cfs at Freeport (Perry et al. 2018, 2019). The reduction in Sacramento River inflows to the Delta will also reduce Delta outflow, harming species’ whose survival and abundance is dependent on Delta outflow, particularly Longfin Smelt (Nobrigra and Rosenfield 2018), but also Delta Smelt (Polansky et al. 2021).”
However, the California Fisheries Blog explains how Sites could actually benefit salmon and other fish populations:
“Under current operations, spring and summer irrigation diversions from the Sacramento River also cut flow and raise water temperatures in the lower river, which harms salmon, steelhead and sturgeon. Water diverted to storage in Sites in the winter could substitute for some of the spring and summer irrigation deliveries that currently come from Shasta. A greater percentage of water released from Shasta in spring and summer could then flow all the way to the Delta. More water could also be retained in Shasta Reservoir to protect the Shasta cold-water pool into the fall and as carryover for the following year.”
Steve Evans, a water consultant for conservation groups, suggests that Sites would harm more than fish populations:
“A reduction in the river’s annual surges means less vital habitat for bobcats, wood ducks, tree frogs and migrants including yellow-billed cuckoos.”
The Sierra Club echoes this concern and explains how Sites could lead to a reduction in water quality.
“For years, the freshwater flowing into the San Francisco Bay-Delta, located near Stockton, has been overdrawn. This has resulted in a loss of habitat, fish, and wildlife. The lack of freshwater also creates increased algal blooms that put nearby communities at risk. The tunnel and Sites Reservoir will only exacerbate these problems.”
The U.S. Environmental Protection Agency has also expressed concern that algal blooms could lead to high levels of cyanobacteria, which is common in shallow lakes and reservoirs. Jim Brobeck, a policy analyst for the Chico-based environmental group AquAlliance even predicts that Sites will become a “biological wasteland.”
While it appears that the project’s updated EIR has satisfied some of these concerns, many still feel the analyses done to date are inadequate:
“After review, we were disappointed to find that there was a significant amount of critical data missing from the Project’s environmental reports. Without that information [data such as a Reservoir Operations Plan, rare plant surveys, and inadequate tribal consultation], we are not sure how Sites Reservoir Authority can substantiate many of its claims that it will provide any benefit to the natural environment or mitigate its considerable harms.”
Governor Newsom, in contrast, generally feels that the ongoing resistance from environmental groups is overblown and even counter to the state’s environmental goals:
“The time to get these dam projects (like Sites Reservoir) is ridiculous, absurd and reasonably comedic. In so many ways the world that we invented, from an environmental perspective, is now getting in the way of moving these projects forward that can address the acuities of Mother Nature…permits that take years and years and years.”
It will negatively impact local communities
Groups located in the region but not at the site of the reservoir have voiced opposition to the project. Their concerns are not about the repurposing of the land specifically, since fewer than 2 dozen people live on the land that would become Sites Reservoir. In fact, Jerry Brown, Sites Project Authority executive director, has found that:
“There's pretty good support from those folks who are really giving up a lot in order to make this possible for all the rest of us.”
Instead, the concerns are more about the potential of reducing water flows in the Sacramento and the Delta - and the corresponding impact of such reductions on certain communities’ way of life. Malissa Tayaba, the Vice Chairman of the Shingle Springs Band of Miwok Indians, worries about the impact on the Delta:
"The Delta is being further diminished along with its cultural and traditional resources that Tribes have utilized from the Delta for food, medicine, transportation, shelter, clothing, ceremony and traditional lifeways from the beginning of time. Additional diversions from the Sacramento River watershed will exaggerate an already damaged and diminishing Delta ecosystem and estuary and our Tribe’s ties to our homelands.”
Tayaba also took issue with how the project has moved forward:
“In addition, true and meaningful tribal consultation has not occurred. In fact, my tribe was not consulted.”
Morning Star Gali, a tribal organizer with Save California Salmon, echoes this sentiment:
“I’m very concerned with the lack of proper consultation with the tribes that will be affected within the area the Sites will flood to the tribal cemeteries, the ceremonial sites and the three creeks and will further degrade salmon runs, harming an important food source.”
There are more cost-effective ways to increase water supply
There are 2 main ways to store water: in reservoirs (surface water) and underground (groundwater).
Jeffrey Mount, a senior fellow at the Public Policy Institute of California’s Water Policy Center, argues that surface water storage is no longer ideal:
“What you want is reliable supply and this (type of storage) is not very reliable. You don’t know when you’re going to fill it. There are better ways to improve your water supply.”
The NRDC is also against big dams and reservoirs:
“There will undoubtedly always be some folks who believe the myth that building new dams and reservoirs will be a silver bullet that solves California’s water supply challenges. The reality, of course, is that California already has constructed nearly 1,400 dams and reservoirs, and compared to the excessive and unsustainable demand for water in our state, new dams and reservoirs provide little water—at high cost.”
Instead, water researchers are increasingly pushing for groundwater storage, as Heather Cooley, director at an Oakland-based water research center explains:
“Trying to recharge our aquifers, that is where our greatest storage opportunity lies. This is not easy to do and it’s not fast, but that’s the direction we need to head.”
Isabella Langone of the California Native Plant Society argues that groundwater storage is also better for the environment:
“Inundating open space and storing more water above ground is counterintuitive to the direction California water management must go in the face of climate change and California’s goal to protect 30 percent of land and water by 2030. The significant funds proposed for Sites should instead go toward multi-benefit solutions that promote native species, sustainable water management and land conservation.”
Groundwater is very important to California, providing 38% to 46% of the state’s total water supply. It is also more resilient than surface water because it doesn’t evaporate.
Some leaders in Los Angeles, whose regional water district bought rights to Sites water, also believe Southern California should be focusing on groundwater, not surface water:
“We need to do everything we can to invest in local smart water supplies. We need to focus on multi-benefit programs, groundwater remediation and stormwater capture. Sites Reservoir and Delta Tunnel are irresponsible.”
And our groundwater aquifers do need recharging. The California Department of Water Resources estimates that we’re drawing 2 MAF more of water from our aquifers every year than they can naturally replenish. Further, 21 groundwater basins have been designated as critically overdraft and overpumping has led Central Valley ground levels to sink about 1 foot per year.
In addition, groundwater recharging projects can also be more cost-effective:
“The idea of channeling runoff during wet periods into aquifers where cities and farms can pump it out is generally a lot less expensive than building reservoirs and has greater potential. The amount of underground space currently available for putting water may be three times the state’s total reservoir capacity, according to one estimate.”
The rising costs of building reservoirs have implications for who will buy water from Sites Reservoir, argues NRDC director Doug Obegi:
“...in large part due to these costs, the Westlands Water District, Kern County Water Agency, and most other irrigation districts south of the Delta are not paying for Sites and will not get any water from the project (a few irrigation districts south of the Delta have very small shares in the project, like the Wheeler Ridge-Maricopa Water Storage District, which would get less than 1.6% of the total water supply from the project). The project will not benefit the vast majority of water districts that are getting a zero percent water supply allocation in 2021.”
Despite this, Governor Newsom seems to be supportive of doing a bit of everything:
“By setting ambitious targets for expanding water recycling, desalination, stormwater capture, and by expanding storage above and below ground, Gov. Newsom’s plan is achievable and essential for ensuring water remains plentiful in the decades ahead.”
The approved Proposition 1 projects reflect this portfolio approach with $1.86B approved for 3 surface water projects (including Sites) and $724M approved for 4 groundwater projects.
The first question is: Will Sites Reservoir provide California with a meaningful amount of water - without robbing another storage facility to do it? If the answer is “no,” nothing else matters.
The storage capacity of 1.5 MAF is meaningful. Urban water usage is around 10 MAF per year. At the height of the drought 2 years ago, Newsom urged residents to cut water use by 15% - roughly the amount Sites can hold.
But this storage capacity doesn’t matter if we can’t fill it. The California State Water Resources Board’s determination this past August that the Sites Project Authority failed to show that there’s sufficient flow to draw from in the Sacramento River gives me pause. But the fact that analyses by PPIC, the Governor’s Office, and the California Globe all show there is more than enough water leads me to believe we can divert a meaningful amount of water into the reservoir. An analysis just this month, albeit by Sites Project Authority, found that it could have diverted 120,000 AF during just the last 2 weeks.
It seems likely to provide significant value, but will it cause outsized harm to the environment or people in the region? Almost all of the potential harms Sites could cause are based on the assumption that it will draw too much water from the Sacramento River and steal too much water from the Delta. If neither of these assertions are correct, then it appears that most of the possible environmental consequences evaporate. Because Sites is, by design, only taking excess flow, it seems possible to satisfy even the stringent flow minimums put forth by the NRDC and still meaningfully fill the reservoir.
Even if the value is significant and the harm minimal, could California better spend $4-5B on other water storage projects? Sites Reservoir is the only surface water storage project of the 52 evaluated by the CALFED Bay-Delta Program in 1995 to have moved forward, suggesting that it is the best surface water storage option in the state. It’s possible that expanding existing dams - like 2 of the other Prop 1-approved projects are doing - would be more cost-effective, but there are challenges to getting these projects approved and the extra capacity won’t necessarily be located such that those reservoirs can capture excess rainwater or snowmelt.
Should California spend two-thirds of the Prop 1 bond money on groundwater recharging rather than surface water storage? Maybe. But at this point in the process, it would be incredibly harmful to stop the Sites project just because another groundwater project may be somewhat more cost-effective.
It has taken 10 years to get Sites within a year of breaking ground. It still won’t be operational until 2030 and then it may take a few years to fill. Can we afford to wait another 20 years for more water in California? No.
Canceling the project on nuanced calculations would also seriously threaten the state’s ability to attract contractors for surface water storage projects in the future. What company and investors would go through 10 years of bureaucratic hell to have the plug pulled 18 months before breaking ground?
While there are some legitimate concerns and uncertainties associated with the project, California should continue to move forward with building Sites Reservoir.
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