Reservoir levels drop throughout SLO County as dry winter drags on
I hope you read about Nacimiento Lake’s drought difficulties.
It was on the front page of Wednesday’s Tribune. Nacimiento Lake is more than half empty, and our winter rainy season is almost over. The lake’s water level has been going down steadily. The headline said, “Nacimiento has lost half its water.”
There was also a large picture of Nacimiento Lake. The banks of the lake looked bare and wide and dry. The story said the lake was only 40 percent full.
But here’s some good news. As of last Friday, after a couple of rainy days, the level of Nacimiento Lake rose to 43 percent full, according to a report from the Monterey County Water Resource’s Agency.
And it turns out that 43 percent of Nacimiento Lake equals 160,610 acre-feet of water that is still in storage. As you probably know one acre-foot means enough water to cover one acre to a depth of one foot.
I should probably also stop here and explain that the Nacimiento Dam and Lake lie wholly within San Luis Obispo County but are owned and operated by Monterey County.
I guess we’re all pleased and maybe surprised that Nacimiento Lake could grow from 40 percent full to 43 percent in two or three days. That confirms the reports that Nacimiento Lake has an outstanding watershed area, which catches any rain that comes near it. I read somewhere that Nacimiento “has the one of the most active watersheds in the state.”
But the Nacimiento Lake water level will start dropping again sooner or later. It all depends on when more water is needed by farms and communities in Monterey County. The Nacimiento River merges with the Salinas River at Camp Roberts. The Nacimiento is the Salinas River’s biggest tributary.
The Salinas is one of those seemingly odd rivers that flow northward. It eventually flows into Monterey Bay near Castroville, if it has enough water left to get that far.
Along the way it provides water to farms and communities in the Salinas Valley of Monterey County. So despite the headline, Lake Nacimiento water isn’t lost: It’s just being heavily used.
And some Nacimiento Lake water is used in San Luis Obispo County. It is piped southward in varying amounts to Paso Robles, Templeton, Atascadero, Santa Margarita Ranch, San Luis Obispo and Cayucos. And some of it goes to customers around the lake.
San Luis Obispo County and Monterey County have a contract that reserves 17,500 acre-feet of Nacimiento water per year for San Luis Obispo County customers. Monterey County people can’t use any of that water.
And San Luis Obispo County water customers must take their shares of the water before each year ends or they lose the rights to it.
As the saying goes, “Water is a deep subject” — and a complicated one. We must never take it for granted.