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Helping Fish Find Their Way Up The Clackamas

Rob Manning / OPB


“And it worked pretty close to 100 years. By those standards, it was a premiere fish ladder back in the day,” Shibahara says.


When PGE relicensed its Clackamas dams recently, it agreed to abandon the ladder, and build a new fish staircase.


“It’s a whole lot easier to go up something with lower steps, instead of a ladder that’s near vertical,” Shibahara explains.


PGE aims to help fish get past the dam’s turbines while maximizing power production. Those turbines can kill fish.


River Mill now has a fish collector — picture a huge horizontal funnel — on the upriver side of the dam. Like a fish ladder — it helps fish avoid the turbines, only for fish going downriver.


“We don’t lose water as a resource for making energy. However, there’s a lot of resources that goes into maintaining these mechanical features,” Shibahara says.



Shibahara’s colleague, John Esler, says the funnel kept PGE from having to screen off all the turbines.


“If you had to do them all, let’s say you had to build one big one out here in the open area, to screen all the water that came in — it’d be huge, it’d be five times bigger than this,” Esler says.


And could’ve been prohibitively expensive.


Biologists say wild salmon and steelhead that get above the dam mostly avoid the collector, and just keep swimming upriver. The big funnel corrals hatchery fish, who tend to get lost, once they’re past the hatchery.


Keeping wild and hatchery fish separate is a persistent dilemma for biologists. The common practice of using handnets can hurt the fish.


Nine miles upriver at PGE’s North Fork Dam there’s an experimental contraption aimed at separating hatchery and wild fish. It’s the brainchild of Garth Wyatt, a fish biologist with PGE.



In Wyatt’s system, human hands never touch the fish. The fish first go to a holding pen.


Wyatt is inside a room a few feet away facing two, three-foot long tanks.


He kicks a pedal. A tanks fill with water and a fish swims in from the pen. A second later, Wyatt identifies it and pushes one of several buttons on a control pad. He’s a gatekeeper, sending wild fish to habitat upriver, and hatchery fish into a pen, to be trucked back down.


“You get pretty good at it. Luckily for us, the majority of fish we’re getting are wild, so you kind of hedge your bets – you always have your hand on the wild fish button, first until you make the determination it’s hatchery,” Wyatt says.


Hatchery fish get their adipose fins clipped. On wild fish, those are intact.


“As soon as I see anything that’s sticking up beyond where a clipped fin would be – I just hit him out.” Wyatt says identifying fish is the easy part.


“You know, I wish I’d played more video games when I was younger. I would’ve been better at actually hitting the buttons. My hand-eye coordination is probably not as good as the next generation of biologists.”


All of these changes — Wyatt’s fish separator, the giant funnel, the fish staircase — are to help federally-protected fish. Helping fish can mean diverting water away from producing power. But PGE’s John Esler says sometimes it means new flows. And where there are no fish, there can be turbines.


“So there’s no new dams, it’s just taking advantage of the water going back into the river, below our facilities.”  Esler says PGE is adding four new turbines capable of producing enough energy to light more than 2000 homes.

Source: http://www.opb.org/news/article/helping-fish-find-their-way-up-the-clackamas/?google_editors_picks=true

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