State could reduce water supply

State water deliveries could be slashed next year if California continues its dry streak, a move that could lead to widespread rationing.

California Department of Water Resources officials Thursday said water agencies could get as little as 15% of their State Water Project allocations, although that figure could go up if Sierra Nevada rain and snowfall return to normal in the coming months.

“We’re clearly making a major call for extra conservation, but also permanent conservation,” said water resources director Lester Snow, who renewed the Schwarzenegger administration’s call for the construction of new reservoirs.

Officials at Southern California’s major water supplier, the Metropolitan Water District of Southern California, say its board soon will discuss whether to initiate cutbacks.

“We are preparing for the real possibility of water shortages and rationing,” said Jeff Kightlinger, the MWD’s general manager.

Last spring was the driest since 1921 in the northern Sierra, depleting reservoirs in the State Water Project, which provides about a third of urban Southern California’s water.

A court ruling to protect delta smelt has reduced pumping from the Sacramento-San Joaquin Delta, the crossroads for sending water south to the San Joaquin Valley and the Southland.

Snow said state reservoirs are starting the rainy season at their lowest levels since 1977, when California was hit by a severe drought.

But state records show that if all the reservoirs that supply California, including major ones on the Colorado River, are taken into account, the picture is not so bleak.

The overall water storage is roughly 70% of the average for this time of year.

This year’s flows into Lake Powell, which catches water from the upper Colorado River Basin, were above average, easing a long-term drought on the river.

Storms are expected statewide in the next few days and state meteorologist Elissa Lynn also said there is a potential for more precipitation this rainy season than last.

Water agencies rarely get their full allotment of deliveries from the State Water Project, which promises more water on paper than it usually has the ability to deliver.

Initial state project allocations, such as the 15% figure announced Thursday, also can change dramatically over the course of a year.

The lowest was in 1993, when the state anticipated that it would deliver only 10% of its customers’ water requests. But conditions improved and contractors wound up getting 100%.

Two dry years in a row in the state, delta pumping cutbacks and an eight-year drought on the Colorado River led to scattered urban rationing this year and irrigation cutbacks in the San Joaquin Valley.

The MWD, which supplies water to agencies that serve 19 million people, mounted a voluntary conservation program that Kightlinger said has reduced water use by 8% to 10%.

But the MWD’s Diamond Lake reservoir is nearly half empty and the agency’s water reserves are down by a third.

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bettina.boxall@latimes.com