Over the Hill

Nacimiento Lake a far more reliable water source than El Niño

Nacimiento Lake, seen here in April 2015, has gained about 50,000 acre-feet of water this winter.
Nacimiento Lake, seen here in April 2015, has gained about 50,000 acre-feet of water this winter. jjohnston@thetribunenews.com

In October, I wrote a column expressing my hope that we could rely on El Niño and Nacimiento Lake to help us survive the current drought and future dry spells.

Well, we just had an El Niño winter, but our rainfall was still below average. Nacimiento Lake, however, showed itself to be a reliable water source.

So I’m not surprised that five communities in our county are officially increasing their rights to Nacimiento pipeline water. Also, two new participants will get some of that pipeline water. They are the Santa Margarita Ranch Mutual Water Co. and the Bella Vista mobile home park in Cayucos.

El Niño, as you know, is the name of a weather system that visits us some winters. In an El Niño winter, the temperature of the Pacific Ocean rises along the West Coast, often causing heavy rains. This past winter’s El Niño did cause heavy storms farther to the north, but around here it was disappointing.

In my hometown, Paso Robles, the city rain gauge is at 13th and Paso Robles streets. The city water division says our total rainfall so far this season (since July 1) was 13.18 inches. Paso Robles’ average annual rainfall is 14.11 inches.

I had hoped we would decisively exceed that average this rain season. After all, the three previous seasons produced just 9.51 inches, 6.13 inches and 7.18 inches. I worry about climate change.

As for the Nacimiento pipeline, it runs from the Nacimiento Dam, which is northwest of Paso Robles, southward for 45 miles to San Luis Obispo. The dam and reservoir are entirely in San Luis Obispo County but belong entirely to Monterey County.

Monterey County created the dam and reservoir in 1957 to irrigate Salinas Valley farms and to counter seawater intrusion. Nacimiento Lake can hold up to 377,900 acre-feet of water and has a few times.

An acre-foot equals 325,851 gallons. It’s said to be enough to serve three households for a year. I get a better sense of the size of an acre-foot when I remember it’s enough to fill 5,924 55-gallon drums.

On Tuesday, the Nacimiento Dam was holding back 129,465 acre-feet of water. Early in October, it held about 77,000 acre-feet. So, since then it has gained about 50,000 acre-feet. San Luis Obispo County has a “senior right” to 17,500 acre-feet of Nacimiento water per year. Monterey County can’t use it.

After all the paperwork is completed and signed, our county’s 17,500 acre-feet will be allocated annually like this: Paso Robles, 6,488 acre-feet; San Luis Obispo, 5,482; Atascadero, 3,244; Templeton, 406; Santa Margarita Ranch Mutual Water Co., 80; County Service Area 10A (that’s Cayucos), 40; and Bella Vista Mobile Home Park, 10. The area around Nacimiento Lake gets 1,750.

But remember, the water isn’t free. The buy-in fees for Bella Vista and Santa Margarita Ranch total about $1.7 million. Also, my water bills keep climbing steadily.

Phil Dirkx’s column is special to The Tribune. He has lived in Paso Robles for more than five decades, and his column appears here every week. Reach Dirkx at 238-2372 or phild2008@sbcglobal.net.