Photo provided Columbus City Utilities is hiring a firm to examine alternatives if a sewer line embedded in the dam were to fail or the low-head dam needed to be removed from Haw Creek.
Columbus City Utilities is hiring a firm to provide a risk analysis on a sewer embedded in a low-head dam.
The Columbus Utility Service Board voted Thursday to engage firm HNTB with a not-to-exceed amount of $64,000. Board president Clayton Force recused himself from the vote due to having a family member who is employed by the firm.
According to utilities engineer Ashley Getz, the dam in question — also known as a weir — crosses Haw Creek just south of Rocky Ford Road. This is not to be confused with the deteriorating low-head dam in the East Fork White River downtown.
Kelso said that the structure identified as a low-head dam was created as part of the sewer system.
“Instead of going underneath Haw Creek, they basically went through it with this low-head dam,” he said. “And then the pipe is embedded in that. And so if you can imagine, basically there’s a hump, let’s say 3 feet high, with a sewer in it, rather than having to come down lower and go under the creek.”
This sewer services “about an eighth of the utility up in the northeast side of town,” said Kelso. After inspecting the dam, the Indiana Department of Natural Resources recommended that CCU run a risk analysis on it.
“DNR is generally looking to get rid of low-head dams,” Getz said. “And since they’ve started looking at this one, we just want to be prepared for when they say ‘Hey, time to get it out.’”
She added that this is one of the utility’s higher risk areas due to being in a creek, though the department did receive a “fair” rating from the DNR’s inspection.
HNTB will examine what would happen if the dam failed and how CCU might be able to pay for the sewer to be rerouted, Getz said. The firm’s analysis is expected to be complete by March.
“This is identified in the master plan as a potential project,” Getz said. “There’s just no real date on it because it works for us, so it’s really the external factors and the risk that would make us do something about it.”
According to the DNR, low-head dams can be “deceivingly dangerous.”
“At times the water around them appears tranquil and inviting; however, moderate to high flows over such dams create strong turbulence and recirculating currents that can push victims underwater, and then pull them back to the face of the dam in a repeating cycle,” the agency’s website states.
