CASHMERE — The custom-cut concrete pieces are lowered by crane and fit together like a jigsaw puzzle. They’ll form the new roof of the Sherman Reservoir, the heart of Cashmere’s water system.
The million-gallon reservoir was damaged last March. One of its neighbors on Cedar Street heard a loud popping sound, which led the city to discover snow had partially collapsed the 40-year-old roof.
“The trusses under the roof had broken and there was a big sag in the roof,” Cashmere Mayor Jim Fletcher said Thursday. “... We said ‘This is kind of an emergency, what are we going to do?’”
The metal and wood trusses had cracked in the middle, but the roof was still being held up by a polyvinyl sheet that’s used to keep the tank waterproof, Fletcher said.
The city was able to keep the tank in operation while it began to engineer a fix, Fletcher said. But first they had to gauge the damage.
“There’s no lights inside, it’s dark and it’s covered, so there’s no way to see what happened in there,” Fletcher said. “We had an insurance agent come out and we actually put a drone inside to try to find out what happened and how bad the damage was.”
They determined the entire roof needed to be replaced, but the rest of the rank was structurally sound, Fletcher said. Instead of replacing it with another metal roof, the city opted for thick slabs of concrete.
“The cost of the two is almost identical. The advantage of the concrete is it’s not steel — It doesn’t have to be treated and the steel would have had to be made someplace back east and transported out here,” he said.
The city hired Cashmere-based Bethlehem Construction to build and install the new roof, Fletcher said.
“As a round tank, each piece they’re placing is actually a custom-cut piece,” he said. “That’s another benefit of using a local contractor, Bethlehem. They could customize each piece as it’s manufactured and if something needs to be re-manufactured, they’re right here to do that.”
The city also had to make several temporary changes to its water system while the reservoir was offline.
“It’s not like you can pull the plug and drain the tank. We actually pumped down the tank so we could keep the water,” Fletcher said. “You have to keep the water system level and keep the entire town in balance. You don’t ever want to lose the balance because all of a sudden one side of the town will go dry and the other side will lose their faucets.”
During the repair process, all the town’s water is being stored in its second, smaller reservoir off Kennedy Road. The Sherman Reservoir was drained in early October and city officials hope to have the 22-foot-deep tank back in service by March.
“We’re picking up some good time because there’s been no snow,” he said. “The next step is they’ll grout all those panels together and then they’ll put on top of that an insulation that’ll shape to allow the roof to drain.”
The city expects the roof replacement to cost around $1 million with a large portion covered by insurance, Fletcher said.
“Fortunately, we have a very good insurance policy that will help us cover most of the cost,” he said. “… It certainly helps our budget that we can make these repairs without have increased rates on the citizens.”
Having the reservoir back online before summer hits will be important, Fletcher said, since it’s key to water operations for the city’s nearly 1,400 customers.
“It’s invisible to most everybody in town, but it impacts most everybody in town,” he said.