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Robot to snap shots in Ottertail water tower

City officials hope the Ottertail water tower will be looking its best for an upcoming photo shoot.

Well, maybe not exactly a photo shoot, but the water tower will be photographed in detail to give the city an idea of the tower's condition. Behind the camera will be a robot, designed to inspect the tank without necessitating either hiring divers or draining the 150,000 gallons of water stored in the tower.

In the past, the city of Ottertail considered hiring divers to manually inspect the tank. However, after conferring with the city's engineer, Ottertail maintenance supervisor Lee Sherman reported to the Ottertail City Council at a March 19 meeting that they came to the decision that a robotic inspection would be the better way to go.

"We want it to be the least intrusive as it can be," Sherman said of their decision. He mentioned that draining a tank can cause additional strain on a city's system.

Sherman and city engineer Chris McConn, with Interstate Engineering, received quotes from five businesses that do water tower inspections. Both the quotes given and the methods used varied greatly from one company to the next.

On the high end of the spectrum was Liquid Engineering, the only outfit of the five that utilizes divers to inspect the tank. Their quote came in at $3,295.

Pittsburg Tank, the company that uses the robotic method of inspection, had the lowest quote at $1,250. However, unlike Liquid Engineering, where the divers clean the tank, the robotic inspection does not include any cleaning.

Sherman explained to the council that the robotic method is a relatively new form of a water tower inspection. One of the greatest benefits is that the entire process is completely sanitized, so there isn't a chance of diseasing the tower.

"They'll take pictures and make recommendations," Sherman elaborated on what Pittsburg Tank will do as a part of the robotic inspection. "Then, it's up to us to decide what we want to do."

After weighing the options given for the water tower inspection, councilman Terry Wagenman voiced his opinion that the city should put their faith in the recommendation of their city engineer. A motion was approved by the council to hire Pittsburg Tank to clean the tower with the robotic method of inspection.

What the city hopes the camera-wielding robot will discover is a clean tank, free from the thick sledge which can accumulate over time on the bottom of a water tower. With the city having a fairly new system, Ottertail's water tower shouldn't have a lot of build up. The tower is relatively young-- at six years old.

Councilman Don Patrick questioned Sherman about whether or not there is a standard rate of sledge accumulation. Sherman indicated that he wasn't sure of the numbers, but mentioned that he was informed that city water towers should be inspected every two to three years.