TUSAYAN, Ariz. — When it comes to catastrophic flooding, most people worry about their homes and businesses, but a much more devastating casualty is sitting just off the main drag, surrounded by forest and flanked by unassuming employee housing.
Should a 100-year flood event occur, the Tusayan Sanitary District would be on the front line, and a failure of the site’s control measures could have serious consequences for the town.
Bob Petzoldt, general manager of the Tusayan Sanitary District, which oversees the wastewater treatment plant off Long Jim Loop Road, said the plant had its own flood survey done to assess the risks. That report said a flood of about 4,300 cubic feet-per-second (cfs) would completely wipe out the plant.
Petzoldt said the plant wouldn’t see any negative effects up to about 2,500 cfs – the property contains a dike around the part of the property in the floodplain which channels water around the wastewater holding ponds. Anything more than 2,500 cfs, and water could overtake the dike and push sewage out of the ponds.
“That would wash more than a million gallons of sludge into the (Kaibab National) forest,” Petzoldt said, while noting that several employee housing complexes are also located downstream from the plant.
That’s why Petzoldt is also anxiously awaiting the return of studies undertaken by the town of Tusayan as part of its bid to obtain a floodplain permit from Coconino County for the Ten X housing development.
“A lot of things have been built without these studies,” he said. “We need to identify an accurate number and enforce ourselves to that. If it turns out to be more than we can handle, we need to fix it, period.”
Petzoldt said he hasn’t seen any floods of the catastrophic variety during his tenure at the Sanitary District, but said he has seen the water creep up the sides of the flood channel near the top while rising up to the doorsteps of the Holiday Inn employee housing nearby.
Once the numbers come back, Petzoldt said the Sanitary District will take more mitigation measures to ensure a surge of sewage doesn’t spill over, effectively shutting down the town for several months. Some measures include building up the dike on the east side of the plant for more protection of the holding ponds and enhancing the existing flood channel to handle more water.