Thursday, June 14, 2012

Reviving a river: Getting fish around those dams

Today, you’re hearing again from the head of our Maine field office, Laury Zicari. Last time we talked about the long history of native fish in Maine. Now, learn how we help get fish up and around those dams using fishways. 


Working to relicense hydropower projects while accommodating native fish is a challenge.

This past week, our team got together to do their annual compliance inspection. The team includes our Federal Energy Regulatory Commission hydropower relicensing biologist, Steve, the Natural Marine Fisheries Service (NMFS) engineer Don, three fishway engineers from the our regional office, two NMFS law enforcement agents and hydroplant operators.
The inspection focused on compliance with fishway operating criteria and turbine operation protocols at the larger hydroelectric plants. 

What’s a fishway? It’s a structure that allows fish to migrate upstream over or through a barrier to fish movement, like a dam. The very best fish passage is the complete removal of the dam, like at Great Works Dam. When that’s not feasible, fishways can be installed to allow passage over or around the barrier. Fishways are required at these projects to open up habitat for the descendants of those migratory fish that were such an important part of the Native American culture in Maine.

Over the course of one day, we visited the Veazie Project, the second oldest hydroelectric generating plant in the United States (the first was at Niagara Falls). It was built to power the nearby communities’ trolley system in about 1906. These older dams with older turbines had to have fishways installed into existing dams and turbine/generator configurations – thus they were constrained by space, just as you would be if you try to renovate a colonial era house and refurbish a bathroom that was stuck in the corner of a bedroom, or need to rewire the old house, or install a new heating system. Ya work with what ya got!

One dam’s fishway was a series of pools – over three dozen arranged in a serpentine manner. The fish swim into the series of pools, lured upstream by a flow that gets their attention. The flow gets them moving up into one pool, over two, then up to the next row of pools. Several fishways were more traditional and looked like ladders with a long series of stair-step pools.

The most modern one, at West Enfield, was built at the same time the dam was modernized. So there was enough space for a wide and long fishway half the size of a football field. The same principle applies; here, the fish are attracted to two openings, and they climb pool to pool up slope until they reach the elevation of the pool above the dam. We also came across fishways built during the last 100 years that were abandoned but signify that folks began to understand the impacts to blocking fish from their spawning grounds. 

This is part of a series on fish passage. Read the other blog posts here.

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