Noticing a difference in your tap water, Calistoga?
While there is still fencing and paving work to be completed in the coming months, Calistoga’s brand-new, state-of-the-art Feige Water Storage Tank has been operational as of December.
The tank, now delivering high-quality water throughout the city, is outfitted with the newest technology and some interesting features.
For one thing, it’s built up to state code to withstand a very large earthquake.
The tank sits on a large concrete base and is weighted with seismic anchors. The anchors keep the tank from overturning during a seismic episode. Once momentum gets going, the water inside a million-gallon tank can be quite forceful. Due to the retrofitting, the tank is also approximately nine feet taller than the previous one.
“Believe it or not, the top panel is just for sloshing room when a seismic wave happens. So the wave is theoretically never supposed to hit the roof,” said Derek Rayner, Calistoga deputy public works director.
Along with the seismic anchors, large, flexible seismic joints are also attached on the inlet and outlet piping near the base, so that in the event of an earthquake, the joint can move in any direction without breaking.
“It can move out, it can move in, up, down, and sideways,” Rayner said.
Calistoga’s previous water storage tank was more than 50 years old, constructed of welded steel. The new one also has steel panels, but they are glass-lined, which serves several purposes, one of which is water quality.
The difference is like drinking, say, beer, out of glass versus a can, Rayner said.
The standard-issue cobalt blue-colored tank is located just off Petrified Forest Road on city-owned property.
Before the 6.0 earthquake that shook Napa in 2014, the city had determined the old tank needed to be repainted, recoated and seismically retrofitted, and it would be more cost-effective in the long run to build a new one.
Subsequently, the city secured FEMA earthquake grant money. It just happened to be good timing as a report was already written stating the old tank was seismically deficient, Rayner said. Thus grants covered 75 percent of the project and the city paid the reminder.
City councilmembers in early 2018 approved a contract to allow for a replacement.
Calistoga gets 30–40 percent of its water from Kimball Reservoir and the rest from the state water project that pulls water out of the delta, pumps the water up to Cordelia and from there to all the cities in the surrounding area including Napa. That water goes through the Jamieson Canyon Water Treatment Plant.
The million-gallon tank has plenty of water storage room for the population Calistoga has, Raynor said, notwithstanding future developments. The two new resorts going in will not put a strain on the water, he said.
The new tank’s technology includes a computer system that monitors the water level inside the tank, how much water is going in or out, and how much chlorine is in the water. It also includes mixers and a THM (trihalomethanes) removal system, and automated chlorination.
The water is always moving inside the tank, which is a good thing. The tank’s design improves efficiency and circulation of water/chemical mixture which reduces staleness of stored water.
Every 10–15 years, steel tanks like the old one would have to be drained and coating re-applied inside and outside, then refilled. Because this one is glass-lined it won’t have to be recoated.
In fact, the new tank will not need much maintenance at all. About every five years divers will go in and vacuum the tank. They do it while it’s full, to keep it clean of any sediment.
“That’s why we picked the glass-infused tank, it tends to be less maintenance intensive,” Rayner said. “In 30 years I’m sure we’ll have to go in and put some more sealant on, but it should be a pretty durable tank.”
Water quality issues the city has dealt with in the past should be clearing up as well. Lately THM levels have been lower and the new tank will help reduce them even lower.
“It’ll help generally because there is more mixing in the tank so the water should be fresher, well-chlorinated, so it’s safe to drink for sure,” Rayner said.
The city is also planning to flush the fire hydrants once a year, which will also help.
“You have a lot of water in the pipes throughout the city, so you want to overturn that water too,” Rayner said.
When that happens, people should be aware they will notice a difference in their water.
“A lot of times after it’s flushed people will see discolored water come out of the faucet and will think ‘uh oh, what happened?’ A brownish or reddish tint and maybe a little sediment. But that’s just because the system has been turned over. In that case just leave the faucet running for a minute or two to flush that water out. The clarity should come back and the water should be better than it was before,” Rayner said.
The next flushing will be in February or March.