Water from Nacimiento Lake is coming in handy

The current drought is parching San Luis Obispo County and most of the rest of California. So I was pleased to learn that our county has 7,641 acre-feet of surplus water.

Reservoirs in this county are depleted below their average levels. Groundwater levels are also dropping. A number of wells have gone dry. And yet we have 7,641 acre-feet of surplus water.

An acre-foot is a lot of water. It equals 325,851 gallons. That’s hard for me to visualize. So I picture a football field, minus five yards at each end, covered with water one foot deep. That’s about an acre-foot.

That 7,641 acre-feet of surplus water sounds too good to be true — and it is, sort of. The water is in Nacimiento Lake. It belongs to the Nacimiento Water Project, which built the pipeline that carries Nacimiento water to Paso Robles, Templeton, Atascadero, San Luis Obispo and part of Cayucos.

It’s been delivering the water since 2010. The pipeline was built bigger than presently needed. It can carry more Nacimiento water than those five communities signed up to get. It was oversized to serve the county’s future growth, which may still happen.

Nacimiento Lake belongs to Monterey County, but it’s entirely in San Luis Obispo County. The dam was built in 1957 to supply water to the farms and communities of the Salinas Valley in Monterey County. The Salinas River flows northward out of our county and through Monterey County toward the ocean.

The two counties ended a water-rights conflict in 1959 by agreeing to a contract. It guarantees San Luis Obispo County the exclusive right to 17,500 acre-feet of Nacimiento water per year. But any of the water that isn’t used that year can’t be carried forward to the next year. It just goes away.

Paso Robles signed up for 4,000 acre-feet of Nacimiento water per year; Templeton, 250; Atascadero, 2,000; San Luis Obispo, 3,380; and Service Area 10 in Cayucos, 25. They share in paying the pipeline’s costs. In addition, 1,750 acre-feet is set aside for Nacimiento Lake-area water users.

Other factors also affect the annual amount of surplus water. For example, in some years any of the five communities may take less water than their allotted amounts. The Nacimiento Project calculates its surplus water for this water year, ending Sept. 30, to be 7,641 acre-feet.

Any of the original five communities may buy some of that surplus water if they need it. Other communities, businesses or individuals may also buy in, but they would have to construct pipeline connections and treatment systems for any human consumption, and pay other costs. There may also be other restrictions. For more information, contact the county Public Works Department.

I wonder if any of the protesters who fought so stubbornly to keep Nacimiento water out of Paso Robles feel differently now during this drought.

This story was originally published May 7, 2015 at 5:05 PM with the headline "Water from Nacimiento Lake is coming in handy."