KODIAK — A wooden dam that provides drinking water for the small Spruce Island settlement of Ouzinkie is rotting and on the verge of collapse, but how to fix the structure remains a big question, a state official said.
The Mahoona Dam, built in 1986 and improved in 1996, provides drinking water and electric power to the settlement of 161 people in south Alaska, the Kodiak Daily Mirror reported. Rotting was discovered during an inspection this past summer, and officials responded by lowering water levels to ease pressure, state dam safety engineer Charles Cobb said.
“We were trying to reduce it as much as possible . while still providing enough water to get the city through the winter,” he said. “It’s probably one of our most serious concerns in the state.”
Replacing the dam could take two or three years and would cost about $6 million — money that would be difficult for the settlement to find.
“The funding is what’s really hard for these places like Ouzinkie that don’t have big tax bases,” Cobb said.
Officials have been considering structural repairs, Anchorage engineering consultant Matthew Morrow said. But that, too, could be costly.
“Someone would have to come up with a significant amount of money to go out there for a week to three weeks, depending on the scale of the problem,” he said. “At best, those are temporary repairs.”
The dam is about a mile and a half east of Ouzinkie proper, and no homes are threatened if it gives way. Nearby, however, is a power plant that has several hundred thousand dollars’ worth of new equipment that was installed in recent years with Denali Commission funding.
The city’s new water treatment plant is also nearby, but should be undamaged if the dam breaks at the lower water level. But the small flood that would follow a dam break would be just the start of Ouzinkie’s problems. The community would be left without cheap hydroelectricity and its water system would be left dry.
As a backup plan, Morrow said the city is getting the “infiltration gallery” — basically a large well — ready at the water treatment plan.
“It’s basically a big manhole down at the water treatment plant that they can draft water out of and bring up into the water treatment plant,” he said.
To back up the hydroelectric plant, there are diesel generators, but with diesel at more than $4.50 per gallon, running those full-time would raise costs considerably.
City employees are using their spare time to put in an all-weather road to the dam site, which would be needed during repair or construction of a new dam. It’s a small step to reduce future costs, but it’s an important one, Morrow said.
“They’re doing everything they can to reduce the project budget,” he said.