Minimum water allocations for the Central Valley Project


As California enters a third year of drought and its reservoirs are at low levels, the federal government has announced plans to deliver minimal amounts of water through the Central Valley Project, alerting many farmers to prepare, in which case no water to get out of the system year.

The Federal Bureau of Reclamation, which manages the project’s dams and canals, announced a zero-water allocation for irrigation districts that serve many farmers throughout the Central Valley. Cities receiving water from the project in the Central Valley and portions of the Bay Area have been allocated 25% of their historical water use.

“Conditions are very dry. So we have to be very careful with these allocations,” said Ernest Conant, the bureau’s regional director.

After a wet start to the rainy season in October and December, the state endured an extremely dry spell in January and much of February. Conant pointed out that January and February are on track to be the driest on record.

Without those critical months of snow and rain, the state has less to look forward to boosting major reservoirs, which were already low after two dry years.

Last February, the Bureau of Reclamation began allocating 5% to many agricultural water users and 55% to cities. But last spring’s hot, dry conditions shrunk rain and snowmelt inflows much more than expected, Conant said, and the agency decided to reduce allocations to 0% for irrigation districts and 25% for cities — the same Cuts that the agency will begin this year.

“We are being criticized by the farming community for these low allocations, but we have to be prudent and careful in these very dry conditions,” Conant said. “If it doesn’t rain in March, it could get worse.”

The Central Valley Project covers 400 miles from the Redding area to the southern end of the San Joaquin Valley, with 20 dams and approximately 500 miles of main channels. One of California’s two major north-south water pipelines, the project pumps water from the Sacramento-San Joaquin River Delta near the inlets of the other major system, the State Water Project.

The federal government has completed more than 270 water contracts for the Central Valley project to serve facilities such as large irrigation districts, individual farmers and cities.

The project also provides agricultural water users with priority rights from before the construction of the project, so-called settlement and barter contract partners, who can still receive up to 75% allocations under their contracts in critically dry years.

“There will be certain areas in the Central Valley that have some water, and there will be other areas that really don’t have any additional water,” Conant said. “These farmers will depend on groundwater when it’s available.”

Some areas could potentially get water from other sources, Conant said. But given the state’s low water supply, he said, “we just have to leave some acres fallow” and let farmland dry.

The reduced water allocations will affect Central Valley cities and portions of the Bay Area served by the Santa Clara Valley Water Agency, the Contra Costa Water District and the East Bay Municipal Utility District.

Water utilities in Southern California, meanwhile, have been told to expect 15% of their full water allocations from the State Water Project this year.

The Bureau of Reclamation said its initial Central Valley project allocations, which are subject to change, are based on estimates of how much water will be available from rain, snow and reservoirs. The total amount of water stored in the project’s largest reservoirs has decreased significantly over the past year.

“Our reservoirs are at about 27% of their capacity, about 52% of the 15-year average,” Conant said.

Storms in December brought heavy snow to the Sierra Nevada, but snowpack has since declined to 67% of the season’s average.

And this winter’s biggest storms have brought relatively less precipitation to the watershed that feeds Shasta Lake, the state’s largest reservoir.

Water discharges from the Shasta Dam provide critical cold water for endangered Chinook salmon during the winter. But last summer, when the reservoir was at low levels, the water pouring out of the dam got so hot it was deadly to salmon eggs.

State biologists estimated that only 2.56% of winter hatched and surviving eggs swam downstream past Red Bluff, one of the lowest egg-to-fry survival rates in years.

Advocates of the commercial and recreational salmon fisheries, which depend on the more numerous fall-run Chinook, have criticized the way officials have handled water discharge from the Shasta Dam for the past two years.

“We likely face another year of depleted natural salmon runs due to water decisions that favor a small group of agricultural landowners over the interests of the rest of California,” said John McManus, president of the Golden State Salmon Assn.

McManus and others have criticized what they say were excessive water releases from the Shasta Dam during the drought, which they say left the reservoir too low last year to continue to provide adequate cool water for the fish.

“This underscores the need for more responsible drought planning,” McManus said.

Bureau of Reclamation officials have defended their handling of water releases, noting that the amount of runoff that flowed into Shasta Lake last year shrank to a record low that exceeded their forecasts.

State water agencies have announced they are taking steps to improve water supply projections to account for the impact of climate change on watersheds.

Warmer temperatures have worsened western arid conditions in recent years, increasing evaporation, drying out soils and shrinking river courses from the Colorado to the Rio Grande.

“Soil moisture was very low, and as a result, much of the runoff just sank into the ground instead of draining into reservoirs,” Conant said.

He said water managers are focused on keeping the water downstream of Shasta Dam cold enough for endangered salmon, but “last year was just really difficult because there just wasn’t enough cold water.”

“And so we had poor survival, which was expected, and the same could happen this year,” Conant said.

Conant said dam managers are working with other state and federal officials to ensure cold water flows for the endangered fish.

“But in a very dry year like this year or last year, mortality will be high just because there’s just not enough cold water,” Conant said.

Shasta Lake is now at 37% capacity, or 53% of the average for this time of year. The agency aims to conserve water in the reservoir as much as possible in preparation for late summer, Conant said, when salmon eggs in the Sacramento River need the cold water.

“Our releases from Shasta are the bare minimum required,” said Conant. “We are doing everything we can to keep water in Shasta to have the maximum supply available there.”

The Bureau of Reclamation cited deteriorating runoff forecasts in a new water supply forecast released by the California Department of Water Resources. The Bureau noted that this latest forecast update showed a total decrease of 1.2 million acre-feet in projected annual flow to four major reservoirs — Shasta, Oroville, Folsom and New Melones — between Feb. 1 and Feb. 15.

“The loss of over one million acre-feet of projected inflow in two weeks is concerning,” Conant said in a statement. “We cut out our work for ourselves this year.”

He said the situation called for “enhanced cooperation and coordination” between different authorities, as well as between water users.

In California, according to state data, agriculture consumes nearly 80% of the water diverted and pumped for human use in an average year. When water is available, the Central Valley Project represents a key resource for the agricultural industry.

Westlands Water District, the largest agricultural irrigation district in the county, said the 0% allotment shows California needs to invest more in water infrastructure, including projects for surface and groundwater storage and water transportation.

The district said in a statement that it was “disappointed with the allocation,” but that dry conditions and the federal government’s obligation to meet state-set runoff and water quality standards in the delta prevented the Bureau of Reclamation from making water available to the district place .

Westlands said last year’s drought caused more than 200,000 acres in the district to fall and remain dry. This year marks the fourth in the past ten years that Westlands and other irrigators south of the Delta have received a 0% allocation. Minimum water allocations for the Central Valley Project

Tom Vazquez

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