Despite murky water, diver Jeff Willard could see Friday that a water intake structure at Marion Reservoir was free of zebra mussels.
That is important, because the intake structure is the source of municipal water for Hillsboro, Marion, and Peabody.
Willard, of Liquid Engineering Corporation of Billings, Mont., said he saw some mussels on his way down to the intake structure, but none on it. Fishing line was tangled in a grate covering the intake, and algae had built up on it, but neither poses a serious threat of hindering water flow.
“Overall, I’d say the intake structure is in excellent condition,” Willard said before surfacing.
His dive suit was equipped with a microphone and camera, so his colleagues could see what he saw and communicate with him during the inspection.
Zebra mussels, an invasive mollusk from Europe, were first found at Marion Reservoir in 2008. The mussels can attach to almost any hard surface, and they reproduce so quickly that they can clog intake pipes.
Zebra mussels don’t pose a public health hazard — both water plants are equipped to eliminate any contamination they might cause. Clogged pipes and grates are a bigger concern.
At Hillsboro’s pump house, employees have been removing mussels by the thousands, Senior Water Treatment Technician Morgan Marler said. Marion gets some shells and occasionally a live mussel, Street Superintendent Marty Fredrickson said.
Marler said the reason the intake grate hadn’t been colonized might be that when both cities are drawing water, the flow is too strong for mussels to attach.