On September 17, the flow in the Boise River dropped from 621 cubic feet per second (cfs) to 335 cfs. The drop occurred at Barber Dam, a hydroelectric plant east of town.
The dam is operated by Enel Green Power, an international hydropower company. The company leases the plant from Ada County. According to Enel operations director Conrad St. Pierre, an electrical failure on the Idaho Power circuit occurred the morning of September 17.
“And so as a result of the power outage," says St. Pierre, "our generating equipment was put into emergency stop automatically by plant controls, which resulted in an immediate stop of flow through our turbines.”
St. Pierre says the pool behind the dam allowed water to spill over, which meant the river continued to flow at a lower level even as the power was off. He says after his operators identified the problem, they contacted Idaho Power and waited for the company to make repairs. St. Pierre says these kind of events happen with plants that rely on the power grid, and Enel did everything it could. The power came back a few hours later, and the river’s flows returned to normal levels.
This is not the first time this year for a sharp drop in flow because of a power issue at Barber Dam. Back in February, an electrical outage shut down the plant, causing the Boise River to run nearly dry for about eight hours. Enel installed a back-up alarm system after the event, and agreed to take part in a river restoration project.
But to Idaho Fish and Game biologist Joe Kozfkay, the change in river flow was concerning. Kozfkay notes the February event was more serious, but says both spell problems for fish and insect populations.
“There’s probably been some mortality due to both of these events," says Kozfkay. "So it’s definitely not an ideal way to operate or manage an important system like this. And so we hope to see improvement with their sort of operations.”
Kozfkay says he hopes to see Enel find a more permanent fix – like a backup generator – to solve the power problems at Barber Dam.
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