The Salinas Dam creates the oldest operating municipal water reservoir in the county, Santa Margarita Lake.
The other major dams in the region are all earth fill dams with concrete spillways.
In 1995, several years after the following story was written, the California State Water Project installed a 42-inch metal pipeline in the tunnel that carries state water through the Santa Lucia Range, thus reducing the size of the tunnel used for Salinas water. The Army still owns the dam.
Phil Dirkx wrote about the dam Oct. 8, 1981:
It holds the waters
If you ever get a chance to walk across the top of the Salinas Dam that holds back Santa Margarita Lake, you will probably wish the single cable handrail were tighter.
Sure, the top is as wide as many sidewalks. But it is 135 feet above the rocky riverbed on one side, and about 30 feet above the water on the other. In addition, the top is not level — it slopes to the edges so water could flow over it easily if the lake ever got high enough.
Jim Harrington, who has been tending the dam for 30 years, said during the big storm of 1969 he crossed the top of the dam every hour on his hands and knees, checking with a flashlight the small steel plates that would reveal any shifting in the massive concrete structure.
He didn’t find any evidence of shifting, although the water was rushing over the lip of the spillway 13 feet deep and roaring down into the river channel below.
The lip of the spillway is 19 feet lower than the top of the dam. The spillway is a huge concrete trough at the north end of the dam. Its function is to carry off the excess water when the lake gets too full.
The dam was built to provide a water supply, not to control floods. But Harrington believes it has reduced flood damage downstream in the North County.
“The old girl took the rough edges off the 1969 storm,” he said.
Harrington is a tall, trim man who looks like he spends a lot of time outdoors. He enjoys hunting deer and cutting firewood, but he does not like having his picture taken. He said he even declined to have it taken for his high school annual, so you won’t find any picture of him with this article.
He lives in a house a quarter of a mile downstream from the dam. He doesn’t worry about living below the dam, but some people downstream do. Whenever there’s a very heavy storm, there are people who are afraid the dam will burst, and they call Harrington to see if he and his family are still there.
“Hysterical women downstream call and say, ‘You haven’t got your wife and family there,’ and sometimes I have to get her out of bed to talk to them,” he said.
He moved his family out during only one storm, and that was because the electricity was knocked out for a long time, Harrington said.
His wife, Harriet, doesn’t mind living below the dam, either.
“I love it,” she said. “I always hope it spills because then I have my own waterfall.”
Her husband, on the other hand, hopes it doesn’t spill again before his planned retirement in about two years because it means more work for him.
Harrington has remodeled and added to the house through the years. He proudly revealed that the large paneled living room was once an Army latrine that he moved and added to the house.
Having a spare Army latrine available is not as strange as it sounds because the dam belongs to the Army, as does the lake, pumping plants and associated works and property.
The dam was planned and built in less than a year. That was in 1941, when the nation was preparing for World War II and the Army was building Camp San Luis Obispo. The dam was built to assure a water supply for the camp.
Deputy County Engineer Clinton Milne said as far as he knows, the Army never really used any water from the dam. The wells at the camp and the Chorro Reservoir provided enough water, he said.
Instead, the water from the dam goes to the city of San Luis Obispo under agreements with the Army that go back to 1943.
The Army also has an agreement with the county to have the dam operated by the county Flood Control and Water Conservation District.
The city pays the operations and maintenance costs and any new capital costs, but it pays nothing on the original cost of the dam and other works.
Milne said the city will get about 6,000 acre-feet of water from the dam this fiscal year for about $87 per acre-foot. That cost is unusually high because extra capital spending is planned this year for pumps and fencing. But Milne said to his knowledge this is still the cheapest surface water in the county.
One of the biggest obstacles the water has to get past on its way to San Luis Obispo is Cuesta Ridge. The water is pumped up to a tunnel for that part of the trip.
The tunnel is about a mile long and was bored straight through the rock of Cuesta Ridge. The northern end of the tunnel, called the north portal, is a short distance from the southbound lanes of Highway 101 on the north side of Cuesta Grade. It is in the wall of the dead end of a rocky canyon.
The tunnel is 9 feet high and 6 feet wide, with water running through it about 2 feet deep. If you stick your head in the tunnel and squint, you can see the light at the other end.
Every 90 days and after every earthquake, someone has to put on hip boots and wade through the tunnel to check its condition.
One of the people who often has to take this stroll is Kenneth “Rick” Meeks, whose job title with the county is Watersystems Worker III.
“What’s bad is when Jim drops us off and we hear this metal door clanged shut and locked behind us,” Meeks said.
They have to have faith in Harrington’s meeting them at the south portal to let them out.
The tunnel is not the only place with a shaft and hollow chambers. The dam has them, too. They are in the part of the dam near the spillway, and they serve no purpose now. They were to be used in the operation of a large steel gate spillway.
The gate would have made it possible for the dam to hold about twice as much water as it does now, but the engineers decided not use it when water was found leaking near the left abutment of the dam during construction.
Concrete grout pumped into the rock formation stopped all but some small leaks, said Milne. There are 23 identified and numbered weep-holes near the base of the dam that are checked each month for flow changes.
Milne said all dams leak a little, and the Army Corps of Engineers also routinely checks the Salinas Dam each year.
The main portion of the dam is solid concrete, 8 feet thick at the top and 13.6 feet thick at the base. It gets its strength from the way it is arched into the water, Milne said.
The dam is shaped something like part of a dome. The center of the top of the dam extends 50 feet farther downstream than the center of the base, Harrington said.
In 1978, a “blue ribbon” committee of scientists studied the earthquake safety of the dam for the Army and concluded “No remedial work is recommended” and the dam’s present condition represents “an adequate level of seismic safety.”
Harrington did not need a scientific report to convince him of the health of the dam.
“All the old girl needs is a lot of tender loving care and she’ll be here 1,000 years,” he said.
A lot more people seem to be worried about the ownership of the dam than about its safety. The Army has indicated it wants to give the dam away, but county people disagree on who should get it — the city of San Luis Obispo or the county.
Robert Mote, utilities engineer for the city, said, “It’s our main source of supply, and if the ownership changes, it should change to the agency that has the right to use the water.”
And San Luis Obispo has the right to use the water. In addition to its agreement with the Army, the city also has a state water permit on the water behind the dam that is second only to the Army’s permit.
But North County people who also have rights to Salinas River water fear they may not get fair treatment if San Luis Obispo owns and operates the dam.
“There is distrust in the event San Luis Obispo takes over, that they may not do it as fairly as the county,” said Paso Robles Mayor Barney Schwartz.
He also pointed out that San Luis Obispo is outside the Salinas watershed.
State regulations give protection to the rights of North County people by saying water must flow in a live stream on the surface of the riverbed from the dam to the mouth of the Nacimiento River at Camp Roberts before any water may be stored behind the Salinas Dam.
Mote concedes his city is not in full agreement with this live stream concept but feels the North County people have nothing to worry about.
“Their rights are controlled by state law,” he said. “We would have to honor those rights.”
Mote was not sure when the Army will make a decision, but he said they are in the process of declaring the dam surplus.
Whenever the decision is made the “old girl” will undoubtedly still be there. But if it takes much longer than two years Jim Harrington will have retired and gone hunting.