Major Salmon Study Starts on Mactaquac Dam

CBC News

Utility needs to make a decision on rebuilding hydro dam or not

CBC News Posted: Jun 01, 2014 2:03 PM AT Last Updated: Jun 01, 2014 2:03 PM AT

Researchers from the Canadian Rivers Institute at the University of New Brunswick will be out studying salmon in the waters of the Mactaquac headpond and the lower St. John River this summer as NB Power grapples with the decision to reopen the dam.

The utility hired the researchers as part of a $2.3-million environmental study to help decide if the Mactaquac Generating Station should be removed or rebuilt.

Little is known about the salmons' movements in the headpond, an artificial lake built alongside the Mactaquac hydro dam four decades ago.

The group is looking for the movements of fish tagged with acoustic beacons. Other teams will investigate sediment deposits and various environmental factors.

“The salmon are used to a flowing river going all the way down to the sea, but now we've put kind of a lake ecosystem in the way and so the current slows right down. They need to find their way downstream,” said Amanda Babin, a Ph.D. candidate in biology.

"The fish are about four inches long and we do some fish surgery, put an acoustic tag inside of them and then we passively and actively track them down the river.”

Babin uses hydrophones to listen for the ping from the acoustic tag.

The project will also track bigger fish including adult salmon, sturgeon and even muskellunge.

Big decisions for dam

The headpond study is one part of a major aquatic environment study being done by the Canadian Rivers Institute. They've been contracted by NB Power to answer questions in advance of a tough decision the utility will have to make soon.

NB Power has three options: rebuilding the dam, maintaining the earthen dam and spillway only or removing it and returning the St. John River to its natural state​

“It's a big decision. It has significant implications environmentally, economically and socially. So it'll be a big decision to make, but until we have these studies completed it's difficult to say how difficult the decision will be,” said NB Power project manager George Porter.

“The core of their work will be completed in about two, two and a half years, and that's the time frame in which we'll be making the decision on Mactaquac.”

The 660 megawatt plant, which officially opened in 1969, was originally expected to churn out electricity until 2068. But its life expectancy is now 2030 because the concrete used to build the power house and spillways began expanding and causing cracks.