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Fill 'er up!

From drought to deluge, Lake Nacimiento relies on rain

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- ON THE LEVEL:  825’ elevation: Top of the dam at Lake Nacimiento. - 800’ elevation: Top of the spillway; total lake capacity 377,900 acre-feet. - 719’ elevation: Lake level Oct. 14, after rainstorm; lake held 67,005 acre-feet. - 700’ elevation: Lake level Oct. 13, before rainstorm; lake held 35,515 acre-feet. - 687’ elevation: Level where Monterey County must stop releasing water, reserving 22,300 acre-feet for SLO County. - 670’ elevation: Monterey County’s low-level outlet; water left in the lake is called “dead pool,” 10,300 acre-feet. - 656’ elevation: lowest of SLO County’s seven intakes for Nacimiento pipeline. - Elevation measured from mean sea level; based on Monterey County figures. -
  • ON THE LEVEL: 825’ elevation: Top of the dam at Lake Nacimiento.
    800’ elevation: Top of the spillway; total lake capacity 377,900 acre-feet.
    719’ elevation: Lake level Oct. 14, after rainstorm; lake held 67,005 acre-feet.
    700’ elevation: Lake level Oct. 13, before rainstorm; lake held 35,515 acre-feet.
    687’ elevation: Level where Monterey County must stop releasing water, reserving 22,300 acre-feet for SLO County.
    670’ elevation: Monterey County’s low-level outlet; water left in the lake is called “dead pool,” 10,300 acre-feet.
    656’ elevation: lowest of SLO County’s seven intakes for Nacimiento pipeline.


    Elevation measured from mean sea level; based on Monterey County figures.

Where there once was deep, shimmering water, Lake Nacimiento’s expansive stretches of dry sand and gravel started making people nervous in the past few months. Before the heavy rainstorm of Oct. 13 and 14, the reservoir was officially considered more than 90 percent empty, even as construction proceeded on the new pipeline designed to carry Nacimiento water to household faucets all over SLO County.

The dragon-shaped lake whose very name means “birth” in Spanish was reborn—at least a little—thanks to the unseasonal deluge. Records from Monterey County show the official lake level rose by more than 20 feet, increasing from 9 percent to 19 percent full overnight.

Monterey County owns the dam it built in the rugged watershed northwest of Paso Robles more than 50 years ago, and it also owns nearly 95 percent of the water Lake Nacimiento contains when full. That water is released from a pipe near the bottom of the dam nearly every day, flowing into the Salinas River where it recharges groundwater in the agricultural valley. SLO County is entitled to 5 percent of the lake’s capacity, or 17,500 acre-feet.

If it hadn’t started raining, Monterey County would have had to stop releasing the lake’s water on Oct. 20 to save what was left for SLO County, according to Courtney Howard, a water engineer with SLO County’s Public Works Department.

Although members of SLO County’s Water Resources Advisory Committee—and lakeshore homeowners—were becoming concerned about the low lake levels and continuing drought, Nacimiento Water Project Director John Hollenbeck said there was no real cause for alarm.

“There’s never been a year when Nacimiento Lake was almost empty and there was no rain. The reservoir is doing exactly as it was designed to do. It’s been dry—empty—five times, and it’s been brim full even more times,” Hollenbeck said.

San Luis Obispo and North County communities are planning to start using Nacimiento water as early as next summer as a “supplemental” source, according to Hollenbeck. The environmental impact statement for the project stated that the Nacimiento Water Project will “remove an obstacle to growth and lead to increased growth in San Luis Obispo County communities and cities.”

Private water companies around the county have also requested the water, according to the environmental report, and would then be able to “change land use to accommodate residential projects.”

Decision-makers in Cayucos have already eliminated the coastal community’s “water supply emergency,” and have started allocating their share of Nacimiento water to vacant parcels in the southern part of the town.

-- KATHY JOHNSTON - PHOTO ESSAY STEVE E. MILLER

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