A likely ‘fourth dry year’ in California, officials say

California’s reservoirs will enter the fall in a slightly better position than last year, but the Golden State should prepare for more drought, extreme weather events and water quality risks in 2023, according to officials.

The latest update to the Department of Water Resources’ climate forecast came Wednesday, just days before the end of the Year of Water, which runs from Oct. 1 to Sept. 30 in California. Officials said some of the state’s largest reservoirs, including Lake Oroville and Lake Shasta, are slightly fuller than they were at this time last year, but remain well below the average.

Water managers are now bracing for a “fourth dry year”, as well as more unpredictable weather and wildfires associated with climate change, DWR Deputy Deputy Director John Yarbrough said during a briefing. a meeting of the California Water Commission.

“We have more tank storage, but we’re still well below average, well below where we’d like to be,” Yarbrough said. Additionally, “we have to prepare and expect to see things we’ve never seen before.”

Part of the challenge facing state water managers is that climate change is making it harder to predict and prepare for water outcomes, Yarbrough said. During the 2022 hydrological year, officials observed significant fluctuations between extremely wet and extremely dry conditions, including a particularly wet October to December followed by the driest January to March on record.

Yarbrough said such variability underscores the need for conservative planning and aggressive multi-agency action.

“When we look at models like this, it really challenges a lot of our practices of how we plan the system, how we’re going to operate next year,” he said.

The 2022 hydrological year also saw warmer-than-normal temperatures and drier-than-normal conditions, he said, but both measures were slightly improved from the previous year. Lake Shasta, the state’s largest reservoir, is expected to end the hydrological year with 1.48 million acre-feet of storage, up from 1.07 million acre-feet last year.

Still, Yarbrough pointed out that California remains in severe drought. Even with improved storage, Shasta is sitting at about 34% capacity, according to the Times drought tracker.

It’s “better than last year, but not good enough,” he said.

Although California has experienced dry spells in the past, Wednesday’s report comes amid significant water cuts and worsening aridity in what researchers described as the 22 years the driest for at least 1,200 years.

Additionally, the state’s other primary water supply – the Colorado River – is also dangerously low, with federal officials warning that another 150-foot drop into Lake Mead could lead to “dead pool” conditions. or the point at which the water falls below the lowest inlet valve of the Hoover Dam.

The looming crisis has put pressure on California and other neighboring states to figure out how to drastically reduce their reliance on the river, and officials have said painful cuts are likely in the coming months.

But climate change isn’t just affecting water availability in California, it’s also affecting water quality, especially in watersheds near wildfires, according to climate action coordinator Andrew Schwarz. at the State Water Project.

More than half of the Feather River watershed — the largest in the Sierra Nevada — burned in wildfires between 2019 and 2021, Schwarz said. About a quarter of it burned at high intensity levels associated with significant tree mortality.

Such fire activity can have a myriad of effects on the watershed, including soil and vegetation alteration. Schwarz said black carbon deposits from ash and burned trees can change the reflectivity of snow to melt it faster, while high heat can make ground waxy, more water-repellent and more prone to runoff. Additionally, erosion and debris flow can send sediment into rivers and other water sources.

“It’s an incredible change in the landscape of a watershed, as you can imagine,” he told the California Water Commission.

This confluence of hazards means state water managers are increasingly factoring wildfires into their climate resilience efforts, Schwarz said, including improving water safety plans for communities. local residents and implementing new sensor data to help experts monitor changing hydrology.

“We will likely have more fires in the watershed, so we can continue to adapt to that and get better information as we go,” he said.

Commissioner Alexandre Makler said the reports underscored the need for continued maintenance and management of state water project assets.

“It has to be in top condition – that’s absolutely essential,” he said, adding that “it’s clear there’s an important capital element to dealing with the risk and combining that with the planning process. “.

California has invested in such work, with the 2022-23 state budget providing $1.2 billion in new funding to reduce wildfire risk through better forest management and $2.8 billion in dollars to support resilience and drought response, among others.

But the growing challenges mean there is still a lot of work to do. Other water priorities for the coming year include maintaining the quality of the Sacramento-San Joaquin Delta, which is the source of municipal drinking water for many communities, while continuing to meet water needs. minimum health and safety standards and to protect species and the environment, Yarbrough told the commission.

It’s also essential to conserve as much reservoir water as possible, he said, “so that we have water again in case we face a fifth dry year.”


Los Angeles Times

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