VA Agreement Highlights Habitat Questions

Water Supply



21
Mar

VA Agreement Highlights Habitat Questions

Restoring marsh and wetland habitat can have significant benefits for dozens of species throughout the Bay and Delta—that’s beyond dispute. But when it comes to saving the Estuary’s most imperiled fish, how much habitat improvements can help in the absence of dramatically increased freshwater flows is a question that has dogged and divided scientists and policy makers for years. As the State Water Resources Control Board considers the latest proposal from the State and water agencies for a flows agreement that would restore thousands of riparian and wetland acres—while dedicating less water to the environment than proposed under an alternative regulatory framework—critics argue that science doesn’t support its underlying assumptions. The debate highlights how much there still is to learn about...
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12
Oct

Rocky Road to a Fresh Enough Delta

Nothing reveals just how much the upper Estuary's seesaw of tides and freshwater flows is micro-managed than prolonged drought, and the resulting fiddling with barriers, gates, and water quality standards to prevent the ocean tides and salinity from intruding too far upstream. Come summer, managers begin to talk fearfully of "losing control of the Delta" and the dreaded outcome: salt water too near the export pumps...
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30
Aug

Drought Plan Means Full Lake, Empty River

In the mountains and foothills of California, an enduring drought has depleted the state’s major reserves of water. There is virtually no snowpack, and most of the state’s large reservoirs are less than 40 percent full. But in the central Sierra Nevada, a trio of artificial lakes remain flush with cold mountain water. The largest of them, Hetch Hetchy Reservoir, from which millions of Bay Area residents receive water, is more than 80 percent full. This remarkable plentitude is the outcome of careful planning by the agency that manages the Yosemite National Park reservoir plus conservation by Bay Area residents, who use less water per capita than most other people in the state—between 35 and 65 gallons per person per...
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30
Aug

The Tunnel Plan: Thoughts a Month Later

It’s now five weeks since Governor Newsom’s Delta tunnel plan was unveiled in a Draft Environmental Impact Statement. Time enough for the main ideas to sink in; time enough for familiar players to strike their familiar positions; and time enough for some of us to burrow deep into its tables, figures, and appendices. To recap briefly: water taken from new intakes near Hood on the Sacramento River would enter a tunnel and flow 45 miles underground before being lifted again to charge up the California Aqueduct at Bethany Reservoir. The tunnel capacity would be 6,000 cubic feet per second, which, if operated full time, could provide 4.3 million acre-feet a year for export to San Joaquin Valley farms and to...
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13
Jun

Flow Deal: Peace Treaty or Trojan Horse?

Promising up to 825,000 acre-feet a year of new water to protect endangered fish and thousands of acres of habitat improvements, the Newsom administration and others hailed the March announcement of a proposed voluntary agreement on Bay-Delta flows as the beginning of the end of California’s water wars, and a boon to the Bay-Delta ecosystem.  “We think this has the promise to give us more benefit for ecosystems because we would be combining both flow and habitat assets,” says California Natural Resources Agency spokesperson Lisa Lien-Mager. And by providing an alternative to government mandates already in the works, proponents say the deal will head off litigation that could delay guaranteed environmental flows for years. Following a decade of stop-and-start negotiations,...
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chart by Hutton
13
Apr

An examination of 50 years of records reveals an apparent seasonal bias in estimates of freshwater flow from the Delta to the San Francisco Estuary.

The seasonal bias suggests flows were overestimated during the summer months and underestimated during the winter. Estimates of Delta outflow use a measurement called net Delta outflow index (NDOI), which is determined by taking the amount of Delta inflow, from sources such as the Calaveras, Sacramento, and San Joaquin rivers, and subtracting Delta exports, a direct measurement, and net Delta channel depletions. A team led by TetraTech’s Paul Hutton compared NDOI estimates against measured Delta outflow at four points, as well as against the Estuary’s historical salinity record. The study, which appears in the December 2021 issue of San Francisco Estuary and Watershed Science, focused on net Delta channel depletions, which are determined indirectly and involve considerations such as land...
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field in delta with irrigation
13
Apr

Rain or shine, farmers in California use about the same amount of water every year, while residential water use varies considerably with precipitation.

A research team led by UC San Diego’s John Helly processed 15 years’ worth of water-use data from the state’s Department of Water Resources, reporting in the March 2022 issue of San Francisco Estuary and Watershed Science that while “the annually precipitated water supply in the Bay-Delta” varied by 30%, agricultural water use scarcely changed year to year. “The water management system maintained nearly constant agricultural water use even in periods of intense drought, with year-to-year variation of about 7%,” the authors wrote. Residential water use showed more variability, swinging by 20% from one year to the next–mainly, the authors theorize, as the result of voluntary and mandated water conservation during droughts. Though Helly says he had no expectations of...
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15
Feb

Will Salmon Simmer Again?

After two critically dry years that coincided with Trump-era rollbacks to environmental protections, some iconic Delta fish are closer than ever to the point of no return. Last fall, the fall midwater trawl found zero wild Delta smelt, while a coalition of environmentalists and fishermen is asking a federal court to help prevent a repeat of 2021’s near-obliteration of endangered winter-run Chinook salmon. Their lawsuit is just one of several projects....
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16
Dec

The New Face of the Met

On October 17, 1972, the Edmonston Pumping Plant south of Bakersfield began lifting water drawn from the Delta up and over the Tehachapi Mountains toward southern California cities. That moment created a statewide water network stretching from the Trinity Alps to the Mexican border. It also made the Southland’s great umbrella water agency, the Metropolitan Water District of Southern California, an intimate partner and massive player in northern California water affairs. Since that day, many in the north have seen “the Met” as a kind of colonial power, both far away and threateningly present. It pays a large share of the cost of the State Water Project. It owns lands in the Delta. It underwrites research. It often seems to...
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16
Dec

How the West Can Survive Smaller Snowpacks and Bigger Atmospheric Rivers

Mountains are the foundation of water in the western United States, natural infrastructure that captures snowfall during the winter and releases snowmelt over the spring and summer. In California, the snowpack holds nearly as much water on average as all the reservoirs put together, effectively doubling the state’s surface storage. But, as the world warms, we may not be able to rely on this ecosystem service much longer. A new study projects that snowpack shrinkage will likely disrupt the West’s water system well before the end of the century. This finding adds urgency to water managers’ efforts to adapt to climate change. “This is not a problem for later,” says Michael Anderson, state climatologist at the California Department of Water...
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25
Oct

Saving Water Under the East Bay

It’s a matter of semantics as to whether the Bay Area ever really left the drought of 2014-2017 before staring down another, more severe one beginning last year. But a huge lesson for our entire state from that “first” water shortage still being learned today is that more attention must be paid to groundwater. That’s true even in the urban East Bay, where the East Bay Municipal Utilities District (EBMUD) and the City of Hayward are developing a plan to ensure continued sustainable use of freshwater sitting beneath the East Bay flats from Richmond to Hayward. In September 2014, Governor Jerry Brown signed into law three bills known as the Sustainable Groundwater Management Act. Among other things, the Act requires...
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17
Jun

Ancient River Channels Could Speed Groundwater Recharge

By the time California finally began regulating groundwater use in 2014, most of the San Joaquin Valley was in critical overdraft. The Public Policy Institute of California estimates that groundwater pumping in the region has exceeded replenishment by an average of 1.8 million acre-feet per year over the last few decades. This imbalance was even worse during our last drought, when overuse shot up to 2.4 million acre-feet per year. Overpumping puts groundwater aquifers at risk of compaction, permanently reducing their water storage capacity and making surface lands sink. Now, however, San Joaquin Valley groundwater managers must find and implement a fix. The state’s Sustainable Groundwater Management Act mandates balancing the region’s pumping with replenishment by 2040. Managed aquifer recharge...
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23
Mar

Flow Rules Stalled As Tunnel Advances

As California stares down the barrel of yet another dry year, alarm bells are already ringing over conditions in the Delta. Environmental groups, fishermen, tribes, and a host of others are calling on the State Water Resources Control Board to complete and implement a long-delayed update to the Water Quality Control Plan for the Bay and Delta (Bay-Delta Plan), to protect the imperiled ecosystem. At the same time, plans for a structure with the potential to divert more water than ever to southern cities and farms are creeping ahead. By law the Bay-Delta Plan — which establishes minimum flows through the Delta from the Sacramento and San Joaquin Rivers and their tributaries — is supposed to be reviewed every three...
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23
Mar

Sub-Standard Snow

At a glance, the recent winter storms and inches of snow in the Sierra seem like a reassuring sign: more snow means more snow melt, which means more water moving through our freshwater systems during dry summer months. But it turns out that there are different types of snow with differing levels of moisture locked up inside — and the latest Sierra snowfall appears to be holding less water than usual. This means the Bay’s streams and estuaries could have drier conditions ahead, despite this winter’s semi-regular storms. Typically, snow that falls along the Sierra has a high moisture content because of the mountain range’s proximity to the Pacific Ocean, says Dan McEvoy, a regional climatologist with the Western Regional...
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wetland landscape photo
13
Sep

Better scientific preparation could help Delta water and environmental managers respond to droughts more effectively.

That’s one key takeaway from a review of environmental management and the use of science during the 2012-2016 drought commissioned by the Delta Science Program and published in the June 2020 issue of San Francisco Estuary and Watershed Science. “There are lots of mysteries about how to manage water to benefit species, agriculture, upstream and downstream users. I think science is going to be the best solution,” says lead author John Durand of UC Davis’ Center for Watershed Science. Durand and his team based their review on available reports and data, as well as discussions with agency staff, stakeholders and researchers. They focused on water management actions during the drought through the lens of four priorities identified by water managers:...
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05
Aug

Two recent exercises in modeling the hydrological effects of forest thinning and wildfire are yielding intriguing insights.

Hydrogeologist Fadji Maina and colleague Erica Siirila-Woodburn of the Lawrence Berkeley National Laboratory ran simulations of wildfire effects in the Cosumnes River watershed (see map). “We chose the Cosumnes because it’s one of the largest rivers that has no dam in California,” explains Maina. The most significant findings concerned the way wildfire affects groundwater recharge and storage. “It depends on where the wildfire occurs,” says Maina. The underlying rocks—foothill volcanics or High Sierra granites—make a difference. Consistent with earlier studies, the model also showed more snow accumulation after wildfire, but unexpected results include a post-fire increase in evapotranspiration in some downslope areas. Another study focused on the effects of forest thinning on snowpack on the west side of Lake Tahoe. A team led by...
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05
Aug

More than half the water diverted from Central Valley rivers is used to irrigate cattle-feed crops, implicating beef and dairy as top drivers of recent fish declines.

Recent findings, published in Nature Sustainability in March, strengthen the environmental arguments for going vegan while rewriting the familiar narrative that almonds and other high-value tree crops are the top hogs of Central Valley water resources. The study’s authors, led by Brian Richter of Virginia-based Sustainable Waters, focused on the arid West and found that irrigated crops like alfalfa and hay, more than any others, are drying out rivers. The reduced flows are pushing dozens of fish species toward extinction. “We estimate that 60 fish species in the western US are at elevated risk of imperilment or extinction due to flow depletion, and that 53 (88%) of these are primarily due to irrigation of cattle-feed crops,” the scientists wrote in...
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06
Jul

Surface water diversions in California’s Central Valley can be estimated based on readily available climate data, say researchers—a boon to efforts to track groundwater use.

Valley groundwater pumping is calculated as the total water demand minus surface water deliveries. However, today’s water model relies on individually reported diversions across the entire valley, and compiling all these data is a slow process; by the time the numbers are crunched, assessments of groundwater use are already outdated. “It can take years,” says Jordan Goodrich of University of Waikato in New Zealand. “It’s one of the biggest problems we face in tracking the Central Valley water budget.” Overdrafting groundwater can cause subsidence, permanently reducing the storage capacity of aquifers as well as jeopardizing above-ground infrastructure that delivers water and controls flooding. In the March 2020 issue of San Francisco Estuary and Watershed Science, Goodrich and colleagues at Scripps...
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19
Mar

Rebooting the Klamath

In 2002, more than 70,000 adult salmon died on the Klamath River when U.S. Bureau of Reclamation diversions caused water temperatures to spike. In February, the Klamath River Renewal Corporation, including the Yurok and Karuk Tribes, filed to take over management of four hydroelectric dams in the upper watershed. “There’s never been a project that has considered removing four dams at the same time on the same river...
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