Forgive Oakdale residents Jack and Gwen Canario if they’re preoccupied to the point of being obsessed by what’s happening on the other side of their fence.
You would be, too, if sinkholes began opening up right next to your house overlooking the Stanislaus River. You, too, would wonder what might be happening beneath the surface, so close to home and on a piece of land where kids frequently played.
Their curiosity began in February 2015, when a construction crew arrived at the city-owned property next to their place on River Bluff Drive. The crew began building a catch basin to handle storm runoff or water drained from the city’s giant storage tank about 100 yards away on top of the hill. The first of the sinkholes exposed debris left behind from the time when Oakdale residents used to dump and burn their trash on the river bluff. Yes, they actually used to do that, and in this case did so until the early 1960s, though the official dump was a few hundred yards upriver.
The crew compacted the ground in the catch basin and that was that – or so they thought. That, it seems, turned out to be just the beginning. The recent winter and spring rains caused more sinkholes, including one opening up within 10 feet of the Canarios’ property line and about 15 feet from their house.
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Monday, a crew came to investigate and brought along the heavy equipment including big diesel-powered shovels, backhoes and other Tonka toys on steroids. A few feet down they struck a concrete slab three feet thick in some places.
More digging brought historical intrigue. They uncovered part of a round brick structure beneath the slab. Workers poked a hole through the concrete and sent in a probe that hit the floor at a depth of 45 feet. It also showed light fixtures and electrical conduit, and at least one of the light sockets still had a bulb in it.
“Unique and unexpected,” one crew member said.
“I have an active imagination,” Gwen Canario said. “But this goes way beyond it.”
Granted, we’re not talking something in the realm of discovering King Tut’s tomb. Still, what is this subterranean silo and how did it get there? The brick and mortar makes it obvious: Someone built it, sans the hieroglyphs. But when? And why?
The answers? The silo was built during the 1880s as a cistern the residents of the community used to store water for fire protection. Don Riise, founding president of the Friends of Oakdale Heritage board and Oakdale resident since 1949, visited the site and shed some light.
Oakdale’s first home went up along F Street in 1869 and is now home to the town’s museum. Oakdale became a railroad town two years later. Like most that followed, the first home was made of wood. Fires devastated communities, and horse troughs couldn’t hold enough water to save a building. So they built cisterns – at least three of them, including the one just rediscovered on the hill next to the Canarios’ home.
Others, Riise said, were on opposite sides of F Street downtown, to protect the businesses along Yosemite Avenue. Water was pumped into the cistern on the hill using windmills, then ran downhill to points from which old hand-pumper engines like the ones on display at Columbia State Park last weekend could draw. The system was as good as they could muster for the time. Riise believes the city added the electrical equipment as it became available.
Oakdale incorporated as a city in November 1906, just seven months after fire destroyed San Francisco after the earthquake. And by that time, the city had the electrical transmission system needed to operate more powerful and efficient pumps and a better fire protection system. According to George H. Tinkham’s “History of Stanislaus County,” residents passed a $50,000 bond to build a 25-foot-tall cistern filled by electrical pumps pulling water from the Stanislaus River.
The new water system went into service May 12, 1913 – 103 years to the day Thursday. The thick concrete covering the old brick cistern uncovered this week likely served as the foundation for the newer one, Riise suspects. It eventually was replaced by a pressurized system and the concrete cistern was demolished. By the time the dump nearby closed in the early 1960s, the cistern system was long gone and all but forgotten.
One of the two downtown cisterns was uncovered after fire destroyed the middle of the block of Yosemite in 1988, Riise said.
“We wanted to find a way to preserve it – to put some grating over it or something,” he said. But the city manager at the time opted to have it filled in to limit the city’s liability. Riise hadn’t thought about the old cistern system for years, until Tuesday.
The discovery drew quite a crowd, Jack Canario said. Contractors, city officials, Oakdale Irrigation District workers, officials from CalRecycle, historians and others looked it over. Crews will use a slurry concrete substance that will stabilize the area around the underground cistern, compact the soil and that will be that.
Presuming that works, the Canarios can relax. Their home will continue to offer a view of the river from above – not from the middle of it.
Joked Jack Canario, “Turns out we’re still standing.”