For the first time in nearly six years, Santa Margarita Lake is overflowing, sending a waterfall gushing over the dam and into the Salinas River, where the water will rush north on a journey that will eventually end at Monterey Bay.
The lake, also known as the Salinas Reservoir, was at nearly 106 percent capacity Wednesday afternoon with about 23,843 acre-feet of water, the highest it’s been since March 2011. The reservoir level is in dramatic contrast to the end of December, when it was at about 12 percent capacity, San Luis Obispo County records show. The reservoir spilled over about 4:30 p.m. Tuesday.
“This is a great day for the city of San Luis Obispo,” said Aaron Floyd, deputy director of the city Utilities Department, which manages the reservoir that provides the city with some of its water supply. Floyd said he expects Santa Margarita Lake to remain at or near capacity until at least mid-spring.
Halfway through this rainfall season — defined as July 1, 2016, to June 30, 2017 — most areas in the county have already exceeded their annual rainfall averages, PG&E meteorologist John Lindsey said.
Cal Poly, which usually records 22 inches of rain a year, had received 25 inches of rain as of Tuesday, Lindsey said. SLOWeather.com in western San Luis Obispo has recorded 28 inches so far, which is 100 percent more than its average rainfall as of this time of the year. Diablo Canyon has received the most rain it’s had in seven years, with 22.46 inches reported.
The Salinas Reservoir is one of three sources of water for the city of San Luis Obispo, in addition to Lake Nacimiento and Whale Rock Reservoir. On Wednesday, Lake Nacimiento was at 85 percent capacity with 322,525 acre-feet of water. Whale Rock Reservoir was at about 60 percent capacity with about 23,000 acre-feet of water.
Lake San Antonio, just north of Lake Nacimiento, is now 30 percent full at 99,770 acre-feet.
The Monterey County Water Resources Agency, which manages Lake Nacimiento and Lake San Antonio, has been releasing water from Nacimiento — at times more than 4,000 cubic feet, or nearly 30,000 gallons, per second — for flood control purposes, deputy general manager Robert Johnson said.
Johnson said Friday that the releases were necessary to prevent “uncontrolled releases” that could damage infrastructure downstream. Less water was released Wednesday, but Johnson said the amount would increase that night, and the agency would re-evaluate the reservoir Thursday morning.
Tribune staff writers Matt Fountain, Lindsey Holden and Gabby Ferreira contributed to this story.