Is California's drought over? Depends how deep you dig

Hien Nguyen points to a spot on the siding of her San Jose home as high as her armpit. That's how high the water rose last week when Coyote Creek came for her house.

"Everything destroyed!" says the 70-year-old. "All gone."

Inside, the flood filled her bathtub with mud and sludge. The house smells like a wet sock that's been left in the washer for a week.

"Terrible!" she says, shaking her head.

Nguyen is aware of the irony: after six years of saving every drop of water, she's among hundreds living in a shelter because floods ravaged northern California, threatening dams like the one in Oroville.

Now, she says, at least one thing is certain. "We no longer have the drought."

According to the U.S. Drought Monitor, this time last year about 95 per cent of the state was in drought. This year it's about 17 per cent.

"Across the entire state so far we've had anywhere from 120 per cent of normal, to greater than 200 per cent of normal rainfall here in southern California," says Jayme Laber, senior hydrologist for the National Weather Service's Los Angeles office.

So does that mean California's historic six-year drought is finally over? The answer is yes, no or maybe, depending on whom you ask.

"The surface water drought is definitely over," says Jay Lund, director of the Center for Watershed Sciences at University of California Davis. "Almost all the major reservoirs in the state are at or are well above average for this time of year."

Surface water includes lakes and rivers, dams and reservoirs, as well as the water stored as snow. The Sierra Nevada snowpack, which provides a third of the state's water, was measured this week at 185 per cent of normal conditions.

That's why the U.S. Drought Monitor's spring projection shows the drought-stricken areas shrinking to a tiny brown patch bordering Arizona and Mexico.

But UC Davis groundwater hydrologist Thomas Harter insists it's still too early to herald the end of the drought.

"No it's not over," he says, shaking his head and smiling.

Harter likes to think of California's underground aquifers as the state's liquid bank account, which provides up to 46 per cent of the state's water supply.

Residents of the driest areas, especially farmers, have spent most of the last 17 years withdrawing water, Harter says, with only three years of deposits. Getting the groundwater balance back in the black, he says, will take a lot more than just one wet winter.

"We need, in many areas, three, four, five of those to really replenish our groundwater resources to where they were before this last drought," Harter says.

At the National Weather Service, Laber goes further: he believes even that may not be enough.

More pumping than replenishing

"The overall long-term trend is still a decline because there's been more pumping of groundwater than there has been recharge," Laber says. "They won't recover to levels that we've seen even 10, 20, 30 years ago."

David Feldman, who teaches water resource management at UC Irvine, agrees.

"According to the U.S. Geological Survey, if groundwater pumping were to cease altogether in the San Joaquin portion of the Central Valley, it could take decades to fully replenish," he says.

And even when the state is overflowing with water as it is now, Feldman says, much of it just disappears.

"Because it's coming so much so quickly, a lot of it is simply running off into our estuaries and into the ocean," Feldman says.

Drought and flood have always been part of life in California, but many scientists believe both will occur more frequently in the state due in part to climate change.

Warm, dry weather creates more extreme drought, and water that would have been stored as snow will instead fall as rain. That means the state may have to change the way it stores water.

There are almost 3,000 dams and reservoirs in California, and building more, Lund says, may not be the answer.

All the cheap dams are built

"We've already built dams at the places that have the most water available for the cheapest construction cost and operation cost," Lund says.

"So the remaining dam sites are going to be economically difficult to justify. You don't want to spend more on water than what the water is worth for agricultural production or for cities."

So instead of building dams, some experts like Harter believe they should be altered.

"A large quantity of the water that has come out of these over-spilling reservoirs in the last two weeks is going out to the ocean," Harter says. "So we can perhaps take some of that additional floodwater and actually actively put it into groundwater storage."

In May, Gov. Jerry Brown will announce whether the drought is officially over and will set any water restriction targets for the year ahead.

But according to Feldman, asking whether this drought has ended misses the point.

"It isn't a two-dimensional situation where you're either in a drought or you're out of a drought," Feldman says. "We always want to conserve."

But Feldman admits convincing Californians to conserve when they are dealing with more water that they can handle will be tough.

'A sociological challenge'

"It's not so much a hydrological challenge as it is a sociological challenge," Feldman says. "The time to plan for droughts is when you're not in one."

Drought? No drought? As a friend helps throw out the food rotting in her broken fridge, Nguyen says she doesn't care what officials label it. The important thing is that they beef up flood protection measures so this doesn't happen again.

"I can't figure out how can I survive after, but I am a brave woman," she says and laughs. Then she goes back to throwing out food gone bad from a fridge that will have to be replaced.