Following a disappointing end to this year's rainy season and a court order aimed at protecting an endangered fish, Southern California is in line to receive the smallest amount of water from the State Water Project in 16 years.

Ted Thomas, spokesman for the California Department of Water Resources in Sacramento, said in a telephone interview that the state expects to deliver 1.5 million acre-feet of water this year, significantly less than in previous years.

According to department records, deliveries totaled 2.4 million acre-feet last year, 3.5 million in 2006 and 4.05 million in 2005. The last time deliveries approached 1.5 million acre-feet was 1992.

An acre-foot is the amount it takes to cover an acre to a depth of one foot, or nearly 326,000 gallons. It's what two families use in a year.

Bob Yamada, water resources manager for the San Diego County Water Authority, said the sharp decline in deliveries from the massive plumbing system that taps the storehouse of frozen water in the Sierra Nevada will not trigger rationing -- at least not this year.

Even so, supplies remain tight and suppliers have launched media blitzes to persuade residents to cut back, voluntarily, on how much they water lawns and gardens.

For the first time, the region's giant wholesaler, the Metropolitan Water District, is specifically asking people to turn sprinklers off one day a week. And water agencies in San Diego and Riverside counties have launched similar advertising blitzes in the last few days.

Individual communities also are tackling the issue head on. Poway, for example, declared a "Stage 1" water emergency in January, warning residents that if they don't conserve voluntarily, they could face mandatory restrictions later.

Farmers, meanwhile, already are under mandatory restrictions. That's because Metropolitan invoked a plan that slashes deliveries to agricultural customers who pay discounted water rates during times of strained supplies.

Many avocado, citrus and flower growers in North County have had allocations cut 30 percent in recent months.

No 'March miracle'

Supplies remain strained despite the fact more rain fell this winter than the previous one. It was wet in December, January and February, Yamada said, but not enough to reverse the effects of several years of drought.

And there was no "miracle" this March like the one in 1991 that delivered several inches of rain in one month and broke the back of another drought.

Indeed, hardly a drop fell in March and April. The northern Sierra Nevada, source of much of the water that flows south to San Diego and Riverside counties, recorded the lowest precipitation totals for those two months since records began being kept in 1921, Thomas said.

On Thursday, the state water department reported the total blanket of snow over the Sierra is two-thirds as deep as it usually is this time of year, at the end of the precipitation season, and the amount of water flowing into reservoirs is little more than half-normal.

And not only did someone turn off the spigot that was replenishing the storehouse of frozen water, abundant sunshine has spurred people to water lawns more often than usual for early spring, said Bob Muir, a spokesman for Metropolitan Water District of Los Angeles.

"The storms earlier this year have left many people with the mistaken impression that our water worries are over," said Jeff Kightlinger, general manager for Metropolitan, Southern California's biggest water supplier. "Nothing could be further from the truth."

'Save it or lose it'

Consequently, while area residents aren't likely to see mandatory cuts, they are already seeing -- and hearing -- an advertising blitz that is filling the airwaves, cyberspace and newspapers with pleas to conserve.

Metropolitan launched a six-county, $6.3 million "Cut your water use" campaign in April that asks homeowners to avoid watering at least one day a week.

And the San Diego County Water Authority kicked off Thursday a similar, $1.8 million "Water: Save it lose it" campaign that aims to slash residential consumption 10 percent this summer, or 20 gallons a day per home.

Also on Thursday, Riverside County agencies began circulating this message: "A summer must, only water after dusk." They want people to limit watering to 15 minutes a day four times a week, after dark.

Tedi Jackson, a spokeswoman for the Riverside-based Western Municipal Water District, said it makes no sense to water lawns when the sun is out because much of the spray is lost to evaporation.

Neither does it make sense to let water run down the street, said Peter Odencrans, spokesman for the Eastern Municipal Water District, which serves the Interstate 215 corridor of Riverside County. At some point this summer, he said, district residents could find themselves paying $100 fines for watering streets and sidewalks.

The water-wasting penalty is one initiative the Eastern board is to consider in a few weeks, Odencrans said. Another would establish a surcharge for water use above a certain amount to reinforce voluntary conservation efforts.

"We can encourage all we want, but if we get something that affects their wallet, that may be more effective," he said. "We don't want to be water cops, but it has come to that."

Now, more than ever

Likewise, Metropolitan was quick to defend its suggested one-day-a-week rest from lawn irrigation.

"We think it's something that people can do without really sacrificing," Muir said. "In many cases, we are killing our plants because we are overwatering them."

Odencrans said lawns get watered twice as much as they should. He said most need 50 inches of water a year and they tend to get 100.

If people will water less, Muir said, Metropolitan will be able to hold onto much of its 1.8 million acre-feet of reserves in reservoirs such as Diamond Valley Lake near Temecula. If not, as much as 30 percent of those reserves could be depleted this summer.

"Now, more than ever, we're looking for people to help us save our water," he said. "We want to keep water in reserve for an emergency."

Metropolitan is the primary supplier in most of Southern California, quenching the thirst of nearly 20 million people. It distributes imported water from the Sierra Nevada and the Rockies.

While the region is not now in an emergency, there is plenty of cause for concern.

Thomas said that, because a large chunk of the melting snow is soaking into soil still parched from last year, the amount of water flowing into California reservoirs is just 55 percent of normal.

That water eventually reaches the Sacramento-San Joaquin Delta, the hub of the state's gigantic plumbing system.

Making matters worse for Southern California, an August 2007 federal court order restricted the amount that may be piped south there to prevent tiny, endangered delta smelt from being sucked into pumps and killed.

Things look a little better on the Colorado River, the region's other major source, because the Rockies recorded higher-than-average snowfall, said Yamada, of the San Diego authority. But the problem there, he said, is that the river's enormous reservoirs are only, collectively, half-full.

"We're still dealing with the lingering problems of eight years of drought on the Colorado River," Yamada said.

Contact staff writer Dave Downey at (760) 745-6611, Ext. 2623, or ddowney@nctimes.com.

Water-saving tips

1. Water lawns and gardens only between dusk and dawn, to avoid evaporation and interference from the wind.

2. Use a broom instead of a hose to clean patios, sidewalks, driveways.

3. Check your sprinkler system regularly for leaks and replace broken sprinkler heads.

4. Spread organic mulch around plants to reduce evaporation.

5. Turn sprinklers off one day a week.

6. Make sure sprinklers spray lawns, not patios and sidewalks.

Information also is available at these Web sites:

www.bewaterwise.com

www.20gallonchallenge.com

www.enoughh20.com