Alaska Hydropower Dam Helps Sustain Salmon Habitat

A hydropower dam now providing the bulk of electric power for a fisheries community on Alaska’s Prince William Sound also serves to sustain spawning habitat for the fish that have made Cordova famous with seafood aficionados.

The Power Creek hydroelectric plant, seven miles east of Cordova, with installed generating capacity of 6.0 megawatts, provides about 60 % of the power for Cordova from the Cordova Electric Cooperative.

Humpback Creek hydropower plant, located seven miles north of Cordova with a generating capacity of 1.25 megawatts, provides about 10-15 %. A diesel generation facility just outside of the city provides the remaining percentage.

The Power Creek dam is unique in that it is made of a giant inflatable rubber barrier that can be lowered to let the river return to its natural force.

As debris accumulates in the dam’s intake structure over time, managers of the dam want to flush it out periodically, Cordova Electric Cooperative CEO Clay Koplin explained in a video explaining how the two hydropower dams operate.

“We start a diesel generator in town, take the load off of the diesel, turn the hydro plants off and that stops the water flowing through here and then we deflate the rubber dam and let the river go back to its natural course,” Koplin explained. “We flush for 10 or 15 minutes and then we raise the dam back up. We start the hydro back up and it will take back all the system load and we’ll turn the diesel off.  The whole process takes about 30 minutes.”

“Obviously salmon spawning habitat is a huge concern to this community,” commercial harvester Rita Spann said. “And the way that the dam operates is it can release the water and it flushes all of the gravel and sediment down into the creek bed to kind of mimic the natural course of how that sediment would move through that water system and totally minimize the effects on salmon spawning.”

To put the whole hydro project in perspective financially, Koplin said it cost $24 million to build the current dam project after flooding severely damaged the old one in 2006, including the intake and the pipeline and the power plants, plus the road and access roads.

“In the first 20 years of operation, between 2002 and 2022, we saved $50 million in diesel fuel,” he remarked. “So basically, we would have to double the cost of energy if we didn’t have these projects.”

Source: https://fishermensnews.com/alaska-hydropower-dam-helps-sustain-salmon-habitat/