Last month, state water officials eased conservation mandates in response to slightly above-average winter rain and snow in much of California, leading many to speculate that the state’s long-running drought has tapered off.
The El Niño winter that forecasters said could drench the state with rain and snow veered north instead, striking mostly the Pacific Northwest. The amount of rain and snow that hit Northern California was a tick above average and looked impressive mostly because it contrasted sharply with the extreme drought of the previous four years. Southern California was wetter than in previous years, but not by much.
Now, conditions are shifting, and El Niño’s counterpart, La Niña – a seasonal period marked by lower Pacific temperatures that shrivel rainfall in California – is expected to arrive around early fall and could prolong the dry times in California.
“I would be concerned about the drought continuing,” said Dave Pierce, who does El Niño and La Niña forecasts at the Climate Research Division of the Scripps Institution of Oceanography in La Jolla.
Another dry winter could hit at a time when the sources that provide Southern California with imported water – the Colorado River and the Sacramento–San Joaquin Delta region – face existential threats.
The Colorado River is over allocated, meaning there are more demands on the river’s water than there is water. Levels at the river’s biggest reservoir, Lake Mead, hit a record low last month, after dropping in 14 of the past 17 years.
While Nevada and Arizona face cutbacks on river water before California, that might change. Negotiations are underway to distribute cuts more evenly among the three states early on to avoid more severe restrictions later.
Meanwhile, in Northern California’s delta region, environmental protections are increasing. This could mean healthier populations of fish and better water quality, while restricting the volume of water that can be pumped south and the time periods it can be sent.
Without a pair of tunnels to withdraw water from the delta in a less ecologically damaging way, Southern California could lose 440,000 acre-feet of water supply annually, or roughly the amount of water Orange County uses annually now, said Rob Hunter, the general manager at the Municipal Water District of Orange County.
A decision on the tunnels, championed by Gov. Jerry Brown, is expected before the end of 2017.
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