Spotlight |
Fish passage enters new era
Fishheart’s pilot project at the Tunnel Hydroelectric Station has completed a successful first year. This year-one review explores how the innovative hydraulic fishway performed during its debut season, and the lessons shaping next year’s efficiency trials
Below: Tunnel station Fishheart Fishway
IN THE SPRING OF 2025 Fishheart Ltd. deployed one of their innovative hydraulic fishways at the Tunnel Generating Station on the Quinebaug River in Preston, CT, initiating the first year of a three-year program to assess passage of river herring and American Shad. The purpose of the program’s first year was to collect as much information as possible about the optimal positioning of the unit, flows, and bypass spills, so that in the second year the efficiency of the Fishheart fishway can be verified. If successful, the fishway will be relocated to the Stevenson Generating Station on the Housatonic River in Monroe, CT as a
permanent fish passage solution for the same species, as well as lamprey and resident fish. FirstLight and Fishheart reached an agreement for
testing at the Tunnel Project in 2024 after Fishheart completed a successful test at the Santee Dam on the Santee River in Pineville, SC where they passed a total of 4142 fish (16 different species), including river herring and American Shad, in a relatively short migration window due to a high-water event. Fishheart demonstrated an ability to avoid flood damage to its unit by removing and reinstalling the hydraulic Fishheart unit in only eight hours. The first year at Tunnel continued to showcase the fishway as one of the most mobile, adjustable, and cost-effective fish passage technologies to dam owners.
Mobility and adjustability One of the leading factors in FirstLight’s consideration to
move forward with the Fishheart fishway, aside from the significant cost savings, was the mobility and adjustability of the unit. The Fishheart system is extremely mobile, allowing it to be removed and repositioned relatively rapidly, which was especially important during the high- water event at the Santee Dam Project. The floating unit makes it possible to adapt to
site specific conditions and optimize fish passage performance through empirical observation by adjusting position and orientation. This is a major advantage when compared to planning and building requirements for conventional fishways which are permanent structures that are limited in how they can be modified if they are ineffective.
Implementation and deployment Fishheart and FirstLight began the consulting phase
of the implementation process in February of 2025. This included assessing the bathymetry and natural attraction flows at the site, as well as determining anchoring points, all to ensure the highest probability for effective fish passage. After the deployment plan was finalized, the Fishheart unit was delivered to the site at the end of April, unloaded, and assembled in five days; it only required an additional week to deploy the unit into position for the season. This included assembling the pipeline that is connected to the fishway entry unit where fish travel from the unit to above the dam, mounting the anchoring points, and installing guiding nets. For deployment, a crane, telehandler, and boat crew
were required. The crane lifted the Fishheart unit off land and placed it into the water, where the boat crew assisted guiding it into position and then anchored the unit to its anchoring points. In this case, the unit was
12 | September 2025 |
www.waterpowermagazine.com
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