Recent rainstorms have swelled Lake Mendocino, reopening the reservoir to motor boats for the first time since August, swallowing islands raised by the drought and bringing fresh hope to ranchers and water officials.

By Thursday afternoon, the lake had reached 98 percent of capacity for this time of the year, when some space is reserved in the reservoir to help with flood prevention.

Once the level hits 100 percent, dam managers must increase releases to keep it at that level, unless they are given permission to hold back additional supplies.

In March, the reservoir’s storage capacity will rise from 68,400 acre-feet to about 110,000 acre-feet, a change aimed at maintaining adequate water supplies throughout the dry season for people, fish and agriculture along the Russian River. The key to recovery from the drought is filling the reservoir to its maximum capacity in the spring.

“It’s raining, I’m happy,” said Janet Pauli, a Mendocino County rancher and local Water Agency board member. But she has seen the rain dry up before spring in past years, so her optimism is cautious.

“We will be fine if it continues to rain and snow,” Pauli said.

Lake Sonoma, the region’s largest reservoir, also is faring well. It was at 94 percent of capacity as of late Thursday afternoon, according to the U.S. Army Corps of Engineers website. When full, the reservoir offers a two- to three-year supply for the Sonoma County Water Agency, which provides drinking water to more than 600,000 residents of Sonoma and Marin counties.

Other reservoirs in the state, especially the larger ones, are filling more slowly after years of depletion.

Lake Shasta, the state’s largest reservoir and a key source for the system that supplies farms and cities farther south, is at 49 percent of capacity.

“It’s going to take a lot of storms to get us full,” said Don Bader, deputy area manager for the Bureau of Reclamation.

Lake Oroville, the second-largest reservoir in California, is at 39 percent of capacity, and Trinity Lake, the third-largest reservoir, is just 27 percent full.

Still, Bader is heartened by this winter’s steady stream of rainstorms, which have improved conditions.

“We’re on our way,” he said.

You can reach Staff Writer Glenda Anderson at 462-6473 or glenda.anderson@pressdemocrat.com. On Twitter @MendoReporter.

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