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Needle Ice Causes Water Plant Problem



Water intakes at the Archbold reservoirs were temporarily frozen shut Thursday, Jan. 19, by a rare phenomena known as needle ice.

Dennis Howell, Archbold village administrator, informed Archbold Village Council of the problem at its Monday, Jan. 23 meeting.

The condition is so rare, it has only affected the water plant three times in 36 years, he said. The last time was about two years ago, he said.

Howell said the condition only occurs in relatively shallow reservoirs, such as Archbold’s, when there is no coating of ice on the surface of the reservoir, and there is a rapid drop in temperature.

As raw water flows into the water plant intake, it streams past a metal screen under relatively high velocity. As it does, ice crystals, called needle ice, form and attach themselves to the screen, eventually clogging the intake and stopping water flow.

Howell said Scott Schultz, water plant superintendent, tried cycling the intakes open and closed, but could not immediately resolve the problem.

Howell said Schultz could have opened water intakes near the bottom of the reservoir, but water taken from that level can have taste and odor problems, requiring ad- ditional treatment.

Warming Trend

Instead, Howell said Schultz looked at the weather forecast, which called for warming temperatures on Friday.

With a sufficient amount of finished, treated water in storage, Schultz elected to wait until the ice over the intake screens thawed on its own.

By 1 pm Friday, Howell said the ice was gone, and water again flowed into the plant.

Water Loss

In a related matter, councilmen reviewed the water department annual report.

One council member asked about water loss from the village distribution system.

Howell defined water loss as the difference between the amount of water pumped out of the water plant, and the amount that passes through customer meters.

He said there is an 8% difference between what is pumped out of the water plant and what goes through customer meters. In other words, about 8% of the finished water produced by the plant is lost before it passes through customer meters.

Howell said village officials don’t know how finished water is escaping the distribu- tion system.

“We will look into that,” he said.

The water treatment industry standard calls for concern when water loss reaches 12%.

“A few years ago, we had it down to 5%,” he said.

An 8% water loss “is still pretty good,” Howell said.

“We have a relatively new (water distribution) system, and we’ve been good about replacing old waterlines.”



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