Photos from the Vault

A $1 million city treasure is buried in the hills above San Luis Obispo

George Hill of San Luis Obispo engineering firm Jennings Bartlett and Associates gazes toward Tank Farm Road from the site of the new reservoir in September 1974. The old Union Oil tank farm can be seen at upper right.
George Hill of San Luis Obispo engineering firm Jennings Bartlett and Associates gazes toward Tank Farm Road from the site of the new reservoir in September 1974. The old Union Oil tank farm can be seen at upper right.

There's a $1 million 4-million-gallon treasure buried up in the hills in San Luis Obispo.

It's between South Street and Prado Road, and adjusted for inflation, it's worth $4.9 million in 2018 dollars.

By treasure, we mean taxpayer-funded infrastructure.

You can’t see it from the road. But hike the Stoneridge Trail and you can’t miss it — no metal detector or special map is required.

The treasure is a massive water tank that cost about 25 cents a gallon to build and hide in 1974.

It's located in what at the time was called the Edna Saddle, but today is known as the South Hills Open Space.

City services and how to pay for them are a perennial issue, as illustrated by San Luis Obispo's proposed tax increases that would pay for $400 million in new projects.

Bob Anderson wrote about decisions made more than four decades ago in the Sept. 27, 1974, Telegram-Tribune:

Hidden tank cosmetic — and costly

When it comes to keeping its good looks, the city of San Luis Obispo puts its money where its mouth is. As figured by a city engineer, the city is spending at least $200,000 to spare residents the sight of a single water tank.

Earth-moving equipment has already gashed the southern side of the Edna Saddle to prepare the site of a 4-million-gallon tank most people will never see. (The Edna Saddle is the hill south of South Street between Broad and Higuera streets.) The cut is visible from the Lower Higuera area and from Tank Farm Road.

The reservoir, 25 feet high and 170 feet in diameter, will be nestled into a $100,000 cut in the Saddle’s bedrock, 50 feet deep in places, said Assistant City Engineer Wayne Peterson. In front of the site, a $100,000 earthen wall will be stacked on terraced cuts in the rocky hillside. Planted with grass, the wall will conceal the reservoir completely except from above.

Sidewalk superintendents won’t have a chance even to watch assembly of the $330,000 tank. The wall will go up first, 50 feet high at its peak, five feet higher than the top of the tank. Other than an uphill walk, the only approach is via a rebuilt access road, usually clogged with heavy equipment, which turns off Broad Street near Orcutt Road.

The reservoir and a cross-town water main are the two major components of city water-system improvement needed to lift the two-year moratorium on construction south of South Street. Now costing roughly $2 million, the projects were expected to be more in the neighborhood of $1 million, until early this year.

The cost of reservoir concealment has inflated perhaps more than any other part of the work. Until January, site preparation costs for the tank, including cuts and wall, were estimated at $265,000, Peterson said. In May the estimate was revised to $478,000. The low bid, by Madonna Construction Co. of San Luis Obispo came in soon after that at almost $700,000. Adding $330,000 for the tank itself makes it a million-dollar reservoir.

It would have cost about $100,000 less without the wall and at least another $100,000 less on a site which didn’t require such extensive excavation process Peterson said.

But since the tank must be at a certain elevation to operate in the city’s gravity water system, the alternative to concealment would have been a very visible hilltop water tank. More than five times as big as the 3/4-million-gallon tank on Terrace Hill behind French Hospital, the Edna Saddle reservoir could have made a considerable change in San Luis Obispo’s skyline.

Invisibility was a requirement from the start. All locations and plans considered by the City Council were for concealed tanks, and all were estimated at about the same cost, whether hiding the tank behind earth, burying it in the ground, or building it far from where it is needed.

“When the city undertakes a project, it has to be as responsible about the appearance of its project as it expects private enterprise to be,” said Mayor Kenneth Schwartz recently. Since the city regulates visual characteristics by such means as its sign ordinance and Architectural Review Commission, the mayor said, it can't put up a “sore thumb” of its own.

Construction of the tank itself should begin about the end of the year, Peterson said. The reservoir and a water main down Prado Road, plus the main from downtown to the Madonna Plaza area, are on schedule for completion in March or April. If work proceeds as planned, construction that follows the lifting of the moratorium Nov. 1 will begin to tax the water system just as the new reservoir and mains are put into service in the spring, Peterson said.

The $1 million Edna Saddle reservoir and the $1 million cross-town main will create a water system adequate through 1975.

To make the system good until the year 2000, the city has to enlarge mains along Broad Street from Mill Street to Highland Drive, Peterson said.

That work should be considerably less expensive than this year’s, and the question of hiding it won’t come up. Underground is the only place water mains go.

David Middlecamp is a photographer for The Tribune. 805-781-7942,, @DavidMiddlecamp
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