Bad Timing : Rain Fell Faster Than It Could Be Pumped Into San Luis Reservoir

In any typical spring at the San Luis Reservoir, John Willems could saunter onto the half-mile-long concrete pier that connects to four pumping inlets, unpack his fishing rod and cast a line into the dark-blue waters.

But this is no typical spring at San Luis. Although a month of steady, often relentless rain has pushed the water level up substantially, the man-made lake where Willems works as a senior engineer with the state’s Department of Water Resources is so low that no conventional fishing line could reach it.

“That’s the high-water mark, over there,” he said, leaning over the walkway’s railing and pointing at a chalky-white ring that encircles the reservoir. “Usually, you could dive off of here and go swimming. But I wouldn’t want to take that dive--besides, you’re not allowed to fish or swim here.”

Nearly 100 feet below, where tiny waves lap against the pier’s spindly, exposed legs, there is visible proof that the drought is far from over. But there are encouraging signs near this reservoir, which supplies a large portion of Southern California’s water, that recent rains have made a dent in the dry spell.

The changes are most evident in the once-yellow hills that are now a lush green, and in the generous dusting of snow that caps the mountains.

Otherwise, the wet weather may have been a case of too much, too soon. For water officials, an incessant downpour means that pumps have to operate at full capacity to siphon water from brimming canals into the 10,500-acre lake--yet massive amounts of rainwater still escape to the sea. And the reservoir is still only 30% full.

To divert Northern California’s river water from its journey into the San Francisco Bay, huge pumps must lure the water uphill and south from the Sacramento-San Joaquin River Delta. Then it travels down canals toward the O’Neill Forebay, just east of the reservoir, where it is captured for pumping into the reservoir.

During heavy rains, seven electric pumps deliver one acre-foot of water--326,000 gallons, enough to supply a Los Angeles family of five for 18 months--to the canals every seven seconds.

When the water shoots through the canals, another arsenal of pumps sucks it into the O’Neill Forebay and to San Luis for storage. Without the pumps, the 3 1/2-mile-long earth-fill dam--once the longest of its kind in the world--would be pointless, since more water evaporates from the artificial lake than flows in naturally.

“The pumps have been running 24 hours a day, seven days a week,” said H. Duane Knittel, field division chief for the Department of Water Resources at San Luis. “But even with them running full time, about 20,000 cubic feet per second of water runs out into the ocean, under the Golden Gate Bridge, and is wasted.”

Knittel said four more pumps are scheduled to begin operation next year where the Sacramento River meets San Francisco Bay; they would have cut this month’s loss in half. Even so, officials managed to pipe almost 700,000 acre-feet of water into the reservoir in March, raising the water level by more than 100 feet.

Not all of that water will make it to Southern California, though. Because the artificial lake stores federal and state water, San Luis can be considered only 30% full by the State Water Project, which supplies Southern California. And that is almost twice as much as a month ago, when the Metropolitan Water District declared that for their purposes, this reservoir was dry.

When that announcement was made, a frantic television producer from a national network called reservoir officials, announcing his intention to send a film crew to San Luis to photograph the dry bed.

“I told them it wasn’t dry, but they wouldn’t listen,” Knittel said. “They came anyway, only to find it full of federal water.”

Although the rain was welcome, the sudden showers did have their down side.

Flooded fields and submerged trees line the two-lane road that winds from Gilroy over the Pacheco Pass to San Luis. Horses and cattle have been driven onto the steep, grassy hills.

Before the March storms, deer would wander into campgrounds or toward irrigated lawns at noon to nibble on the vegetation. Now they have disappeared.

“Before this rain started, we were catching our limits in two hours,” complained Ken Wilcox of San Jose, angling with two friends under a bridge.

THE SAN LUIS RESERVOIR

The San Luis Reservoir is one of two critical storage facilities for the State Water Project, which serves most of Southern California. Although it has benefited a great deal from recent rains, officials say they need twice as much water in the reservoir before they can resume normal deliveries.