The water level of Lake Nacimiento plunges deep

A view of Lake Nacimiento from the Running Deer district shows how low the water level is this year.

The water level is low, but it has been lower

–Low water levels in Lake Nacimiento are a concern for visitors and residents of the area. Since construction of the Nacimiento River Dam was completed in 1956, the 18-mile-long lake with 165 miles of shoreline has become a popular recreation destination and is home to the Heritage Ranch and Oak Shores communities and the Lake Nacimiento Resort. .

As of Saturday, September 24, the interactive water level graph on Lakes Online shows the water level at 706.48 feet at its deepest point. The minimum pool is 687 feet. The minimum basin is the level at which the Monterey County Water Resources Agency (MCWRA) releases only small amounts of water to support spawning and rearing fish in the lower reaches of the Nacimiento River. “By contractual agreement, the minimum pool volume is reserved for use by San Luis Obispo County,” said Brent Buche, CEO of MCWRA.

The lake has been below the minimum pool four times since 1958, the most recent being 1989, according to the Nacimiento Reservoir elevation graph available from the MCWRA, and pictured below. The California Department of Water Resources reported a five-year drought from 1987 to 1992.

If the lake level reaches “the dead pool” at 607 feet, the water cannot physically drain from the reservoir and “10,300 feet remains in storage,” Buche said. “Dead basin” means that the water in a reservoir cannot be drained by gravity through its dam.

History of the water level of Lake Nacimiento

Influence of droughts

“During the 62-year recording period, the September elevations were ten times as low,” Buche said. “The ability to store large volumes of water at Nacimiento during wet spells has historically allowed the agency to operate during most droughts without the kind of severe reductions in altitude seen during the current drought. Other multi-year droughts such as 1977-78 and 1987-1991 resulted in similar elevation declines.

The five-year drought from 2012 to 2016 did not result in lower levels as dam repairs hampered the ability to release water to recharge the groundwater basin. The groundwater basin is recharged by releasing water into the Nacimiento River, which flows into the Salinas River. The main source of water for the lake is from the Nacimiento River, followed by the watershed surrounding the lake. “A small fraction comes from rain falling directly on the reservoir,” Buche said.

An exception to the influence of drought on water levels occurred in 1969. Even though it was a wet year, flood control releases were made to make room for water. the influx. Additional discharges were made to compensate for the fact that Lake San Antonio has not yet reached its full level of water storage.

Where does the water go?

At the height of the conservation season, Buche said, most of the water released is “put to good use by Salinas Valley farms and urban water providers.” The water is extracted from the groundwater basin by wells with a small amount by the diversion of surface water near the coast. 1-5% of the water is allocated to support fish habitat along the Salinas River. Some 5-10% is lost through evaporation and absorption of vegetation along the Salinas River corridor.

The water used by San Luis Obispo County is extracted through a pipeline through a lakeside facility. The 17,500 acres of food allocated to SLO County represents about 10% of the maximum amount released by MCWRA.

Who owns the lake?

Officially known as a reservoir, Lake Nacimiento belongs to Monterey County and is controlled by its water resources agency. The Nacimiento Dam is under the jurisdiction of the California Department of Water Resources, the Division of Dam Safety (DSOD), and the Federal Energy Regulatory Commission (FERC). The FERC has jurisdiction due to the existence of a 4 megawatt hydroelectric power station.

The Lake Nacimiento Resort is an authorized Monterey County Parks Dealer. The land surrounding the lake is largely private property. Camping is only permitted in designated campgrounds. Reservations can be made with the Monterey County Parks Department or the Lake Nacimiento Resort.

The SLO Nacimiento County water supply system is owned and operated by the San Luis Obispo County Flood Control and Water Conservation District.

A controversial story

The lake was developed and paid for by Monterey County to recharge groundwater for Monterey County’s use, for flood control, to replenish water for fish habitat, and for recreation. San Luis Obispo County retained the rights to 17,500 acre-feet of water per year. This arrangement was an almost immediate cause of conflict between the two counties when, in 1955, the original agreement was called into question. An August 21, 1955 article in a Paso Robles newspaper, the Sunday Review, reported that a “gentlemen’s agreement” with San Luis Obispo County had been challenged by Monterey County. Eventually, an agreement was reached formalizing the amount of water allocated to SLO County.

Even though water waited, residents of SLO County repeatedly voted against the bond measures to fund the water distribution system. The San Luis Obispo County subdivision remained unused until October 2007, when construction of a pipeline began to bring water from the lake to Paso Robles, Templeton, Atascadero and San Luis Obispo. The project was commissioned in January 2011. The cost was $ 76.1 million for three pumping stations, three storage tanks, a control system and 45 miles of pipeline.

An article in a March 2018 issue of The Tribune indicated that unregulated camping at Lake Nacimiento in the 1960s created slum conditions. Campers created sanitation problems because of makeshift toilets or the lack of toilets. Up to 30,000 campers have invaded the banks. The San Luis Obispo County Planning Commission revoked temporary camping permits in 1966.

In 2019, a group representing Lake Nacimiento landowners sued Monterey County for draining so much water from the lake that it “became almost unusable for owners and visitors, resulting in loss of property value.” The trial is continuing and updates are available on the Nacimiento Regional Water Management Advisory Committee (NRWMAC) website.

About the Author: Journalist Jackie Iddings

Jackie Iddings is a journalist and contributing photographer for the Paso Robles Daily News.

About Keith Tatum

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