Water & Drought

Nacimiento has lost half its water — and other SLO County reservoirs are down, too

Less than a year after emerging from five years of parched conditions, another dry winter is taking its toll on San Luis Obispo County reservoirs.

As of Feb. 22, most of the county had slipped back into severe drought conditions, according to the U.S. Drought Monitor. As a result, the region’s reservoirs are all down from this time last year, with some losing substantially more water than others.

Lake Nacimiento, Lake San Antonio and Santa Margarita Lake have all lost significant amounts of water since early 2017.

Lake Nacimiento was 96.5 percent full on Feb. 23 last year. On Monday, it was at 40 percent of capacity, according to the Monterey County Water Resources Agency.

Lake San Antonio was 31 percent full on Monday, compared to 46 percent on Feb. 23 last year. Monterey County manages the two lakes, although Lake Nacimiento is located in San Luis Obispo County.

“It’s Mother Nature,” said Brent Buche, deputy general manager for the Water Resources Agency. “It’s rainfall — it’s lack of rainfall.”

Even though officials release water from Lake Nacimiento to recharge the Salinas Valley aquifer and preserve fisheries, Buche said the agency hasn’t released more water than normal.

“Our releases were not excessive of any other year,” he said.

Santa Margarita Lake in the North County has lost about a fifth of its water — to 79.8 percent capacuty from 101.2 at this time last year.

“We were in a worse state last year,” said Ray Dienzo, the county’s supervising water resources engineer. “The two miracle rain months raised it past 100 percent.”

Rain is in the forecast for San Luis Obispo County this week, but Dienzo said it might not do much for the area’s lake and reservoir levels.

“I wouldn’t expect there to be much of a rise from this little rain,” he said. “The ground still needs to be saturated.”

Still, some of the county’s reservoir levels held steady, in spite of the lack of rain.

DROUGHT MONITOR MAP_Tribune

Whale Rock Reservoir near Cayucos was 72.7 percent full as of Feb. 21. The water level is down only slightly from last year at this time, when it was 73.5 percent full, according to Noah Evans, the reservoir supervisor.

Lopez Lake was at 50.2 percent of capacity on Monday, down just 6 percentage points from last February, when it was 56 percent full.

Evans said Whale Rock hasn’t lost much water because the region continued to get rain into late spring in 2017 and the reservoir wasn’t drawn down very much throughout the rest of the year.

“Last year, we were still filling up the tank, so to speak, through May,” he said.

Evans said he’s not too worried yet, as there’s still “quite a bit of fuel in the tank.”

“We’d like to see the reservoir full all the time,” he said. “... I can worry all I want — I still can’t make it rain.”

Lindsey Holden: 805-781-7939, @lindseymholden

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