Water Outlook Remains ‘Critical’ : Drought: New measurements show that despite March rains, reservoirs will get only 50% of normal runoff this year.

State water officials, trying to sketch out California’s water picture for the coming dry months of summer, released new runoff projections Wednesday confirming their earlier fears that 1991 is going to be another critically dry year.

Even with the March deluge and new measurements showing the water content of the Sierra snowpack to be 75% of normal, hydrologists for the Department of Water Resources said the runoff that feeds the state’s thirsty reservoirs would be only 50% of normal for the year.

In the all-important Sacramento River Basin, which supplies the major state and federal reservoirs, the hydrologists projected runoff for the year at 9.1 million acre-feet, placing 1991 well within the parameters for a critically dry year.

To be classed as a critically dry year, the basin runoff in the 12 months from Oct. 1 to Sept. 30 must be 10.2 million acre-feet or less. In an average year, runoff in the Sacramento Basin is 18.9 million acre-feet. An acre-foot is equivalent to the amount of water a typical Los Angeles family of five uses in 18 months.

“Even with the record-breaking March rains, California continues to experience the second-longest and potentially the most severe drought of this century,” said Douglas Priest, manager of the department’s drought center. The longest California drought on record lasted from 1928 to 1934.

With April failing so far to produce its legendary showers, he said there is little chance that most Californians will get through the summer without some form of water conservation.

In fact, state officials, who in March optimistically predicted that deliveries from the State Water Project to municipal and industrial customers could be increased dramatically, now see little possibility of that happening. At that time, those customers were getting only 10% of the water they had requested from the state project, and officials said continuing rains could make it possible for deliveries to go as high as 35% of the requested amount.

But on Wednesday, Larry Mullnix, the department’s deputy director, said the new assessments of state water supplies indicate that deliveries of that magnitude are not a possibility.

“I think 35% is truly an outside figure,” he said. “It’s not even achievable at the present time.”

As a result of the March rains, the state was able on April 4 to increase deliveries to municipal and industrial customers to 20% of requested amounts. Mullnix said that another assessment of water conditions will be made at the end of April and deliveries could be increased again, but the next increase is likely to be very slight.

He said he could see no possibility of the state making any regular deliveries to its agricultural customers this year.

The Metropolitan Water District, the large Southern California wholesaler, is the prime municipal customer of the State Water Project. Although the district normally receives about half of its water supplies from the state, it has been able to make up for some of the cutbacks this year by relying more heavily on supplies from the Colorado River and by purchasing additional water from a state water bank.

The district provides about 60% of the water used by 15 million people living in Los Angeles, Ventura, Orange, San Diego, Riverside and San Bernardino counties.

The April water projections, issued after an exhaustive measurement of the Sierra snowpack, traditionally give the most accurate picture of the state’s water supplies because the snowpack is usually at its peak at the first of the month when measurements are taken.

“By now, we are far enough along in the season that the outlook is not likely to change a whole lot,” said Maurice Roos, the department’s chief hydrologist. “Occasionally--about one year in 10--we do get a real wet April, and it’s conceivable if we were to get some very nice juicy storms, the forecast could change.”

A new concern, he said, is that windy weather will appear in Northern California, tending to dry out the ground more quickly and making it more absorbent.

As the month of April slips away and the end of the rainy season approaches, state meteorologists were less optimistic that April would be wet.

State meteorologist Bill Mork said a low-pressure trough was developing in the eastern Pacific, which could produce some light rain next week by Wednesday and Thursday, but it would probably fall mostly in Southern California.

“It doesn’t look very ominous. It won’t be a frog-strangler,” he said.

He said that April, unlike March, is turning out to be a typical spring month when weather conditions are difficult to predict more than a week in advance.

Indeed, earlier in the month forecasters were predicting heavy storms, only to see sunny weather.

“It’s typical in April to have systems which aren’t very strong,” he said. “A week away you just can’t pin anything down.”