Despite California’s record snowpack and promise of historic runoff, state and federal water regulators still cannot promise full water deliveries to farmers.

The state Department of Water Resources boosted its State Water Project allocation – a promise of delivery to the 29 districts and local agencies that receive water from the state – to 75% in late March. The federal Central Valley Project promise followed shortly thereafter with its allocation of 80% of contracted deliveries to districts north and south of the Delta. Only the senior water rights contractors were promised 100% of their contracted allocations.

Friant Division contractors will receive 100% of their Class 1 water and 70% of their Class 2 water as Millerton Reservoir is operated in flood control mode because of the record snowpack in the San Joaquin River watershed. Class 1 water is the first 800,000 acre-feet of water for delivery along the Friant-Kern Canal. Class 2 water is available water after Class 1 promises are met.

Reported snowpack conditions in the Sierra Nevada range from about 200% to over 300% of annual April 1 snowpack, according to public estimates. The April 1 snow survey at Phillips Station near Lake Tahoe recorded over 126 inches of snow depth with a water equivalent of 54 inches. This is said to be 221% of average for the location, according to the California DWR.

Snowfall reports from the Sierra Nevada have exceeded 50 feet in many places this season. Mammoth Mountain, a popular ski resort in the Eastern Sierra, reports over 704 inches of snowfall as of early April at its main lodge, elevation 8,900 feet, and 882 inches at the top of the mountain at 11,053 feet elevation.

Some of that water will flow east and south, down the Owens River and Los Angeles Aqueduct, which reportedly suffered a catastrophic failure this spring, according to reports in the Los Angeles Times. Snowpack on the western slope of the mountain range will fill the San Joaquin River watershed and flow through Millerton Lake, a federal facility near Fresno.

“This year’s result will go down as one of the largest snowpack years on record in California,” said Sean de Guzman, manager of DWR’s Snow Surveys and Water Supply Forecasting Unit. “While 1952’s snow course measurements showed a similar result, there were fewer snow courses at that time, making it difficult to compare to today’s results. Because additional snow courses were added over the years, it is difficult to compare results accurately across the decades with precision, but this year’s snowpack is definitely one of the biggest the state has seen since the 1950s.”

Climate extremes

For all the talk on climate extremes by scientists and politicians, state water officials continue to highlight the bust-to-boom nature of winter weather over the past several years. After an epic 2017 that saw Oroville Dam, the cornerstone facility in California’s SWP, come close to catastrophic failure after the reservoir overtopped the earthen dam, the following years were said to be one of the driest on record.

“This year’s severe storms and flooding is the latest example that California’s climate is becoming more extreme,” said DWR Director Karla Nemeth. “After the driest three years on record and devastating drought impacts to communities across the state, DWR has rapidly shifted to flood response and forecasting for the upcoming snowmelt. We have provided flood assistance to many communities who just a few months ago were facing severe drought impacts.”

Nemeth participated in a virtual media call in late March as she announced the 75% SWP allocation. Pressed by reporters to talk about state plans to capture more of the runoff during banner rain and snow years, she vaguely pointed to the state’s support of Sites Reservoir, an off stream reservoir still in the planning stages after decades of discussions and requests. She also highlighted improvements planned for smaller, existing reservoirs and projects that she says could net the state about 4.2 million acre feet of water improvements by 2040.

Nemeth was also asked when, if ever, California could promise a full allocation of water deliveries to its SWP contractors. She said there is a likelihood that the SWP allocation could be revisited by June based on the hydrology then.

“There’s a lot of water up in the Sierra right now,” she said. “There’s more water in the Sierra than our facilities can handle.”

That’s why the state has been asking its existing water contractors to take as much water as possible for storage. She cited the Kern Water Bank, Castaic Lake, and Metropolitan Water District of Southern California as examples of places SWP water could go for storage and later use.

After a dismal start to the water season, California was able to run the Delta pumps that move water to San Luis Reservoir, a facility shared by DWR and the U.S. Bureau of Reclamation. The state’s portion of that reservoir, or about one million acre feet of water, was filled in late March. The federal portion then was about 98% full.

Kings River

The Kings River watershed will be watched this year as the Army Corps of Engineers ordered flood flows be moved to Tulare Lake, which began flooding in late March. The flooding of the lakebed could reduce California’s cotton acreage to the lowest it’s been in decades, according to one cotton industry leader in a social media post.

The Kings River Water Association reports that water content readings in the watershed are the highest recorded and are said to be “far higher than the 126 inches of snow measured by state surveyors near Echo Summit, with a water content of 54 inches (221% of average),” according to a statement from the association.

“The Department of Water Resources makes a big deal of those measurements which tend to be inaccurately reported as being representative of the entire state’s snow conditions,” said Kings River Watermaster Steve Haugen. “You have to use the local data which our Kings River reports far more accurately in representing the huge snow accumulation present over the southern Sierra ranges.”

Haugen termed the record Kings River figures “remarkable” but said they were not unexpected given the onslaught of major snow-producing storm events that a dozen atmospheric river episodes produced over the southern Sierra Nevada, the KRWA statement says. It goes on to point out that the snow depth one year ago at Rattlesnake Creek, elevation 9,900 feet, was just over 10 inches.

Pine Flat Reservoir on the Kings River was at about 70% of capacity on April 1, with estimates of several times the reservoir’s holding capacity contained in the snowpack. Similar stories are being told of other California reservoirs. Turlock Irrigation District reports that 2-3 times the design capacity of Don Pedro Reservoir, a 2 maf facility wholly owned and managed by TID on the Tuolumne River, is contained in the snowpack upstream.

Shasta Lake and Lake Oroville, the state’s two cornerstone storage facilities, are each nearing full pool as snowpack in their respective watersheds is said to be high as well, though not as epic as the southern Sierra Nevada.

“From a Northstate perspective, this was a more typical rain year, which we haven’t seen in a long time,” said Colleen Cecil, executive director of the Butte County Farm Bureau.