Franklin water issues in December explained

Granderson Hamilton, Franklin’s water plant manager, reported to the mayor and city council Tuesday to explain the details surrounding the city’s water access discontinuation and subsequent pressure drop that occurred Dec. 21 of last year.
According to Hamilton, the problem occurred at the plant. He said that once water has been treated and produced, it is stored in two ground tanks. Once in the tanks, the water flows back into the plant and its service basin. From the service basin, high-service pumps send the water out to the city.
There’s an ultrasonic transmitter that transmits the water level information from inside the transfer basin. Working like sonar, that transmitter sends a signal to the bottom of the tank, and back to the transmitter, which then reads the water level. In this way, the control room of the plant is able to adjust and set the depth of the service basin.
“Right now we are set at five feet,” Hamilton said. “Once it gets down to five feet, the service basin valve opens and lets water in from the ground storage, and then once it gets up to seven feet, it closes.
“What happened that night was that the monitor downstairs was reading ‘nine feet,’ stating that we had nine feet of water inside the service basin. But, for some technical reason, the signal that goes to the computer said that there was no water inside the basin. The way our service pump is connected to our scanner system, is that if it [water level] gets below two feet, the service pump cuts off… it will not pump. For some reason, it was reading the signal that we didn’t have any water in the service basin, which was incorrect because we were aware that there was water coming out of the building, indicating that there was water in the service basin.”
Hamilton said that once the personnel at the plant detected the incongruity between water level readings and the actual water level, they switched operating modes from “automatic” to “manual.” After which, they closed the service basin valve to prevent backwash, started up the service pump again, and operated the system manually for the rest of the night.
“The next day, I had the technician from Instrumentation and Control come out,” Hamilton concluded. “He changed out the ultrasonic level system, and from that point on we’ve been operating without any problems.”