European eel.

Fish passage supports ecosystem health, clean water, and people.

Connectivity Matters

Passage of fish, other aquatic life, sediment, and nutrients is critical to maintain thriving freshwater ecosystems, which, in turn, deliver clean water, flood buffering, and fisheries, and provide cultural and recreational value.

Why FishSafe turbines?

Downstream migrating fish want to go with the flow, but hydropower infrastructure can block or alter migration routes, resulting in fish injury or mortality. Traditional approaches to fish protection aim to exclude fish from entering turbines using fine screens, and to route fish around  turbines with low- flow fishways.

However, screening can be ineffective, allowing some fish to pass through and suffer injuries or death in conventional turbines, or harming fish that become impinged on screens or are subject to predation while exposed in fish bypasses. Screening and bypass reaches are also infrastructure and maintenance-intensive, resulting in higher CapEx and OpEx costs to plant owners as well as reduced plant efficiency due to flow-limiting screens.

Natel's FishSafe™️ RHT designs offer an option that is truly safe for fish, enabling numerous species to pass through multiple dams consecutively, and freeing owners of the need to exclude fish from their plants.

conventional turbines with screens can trap fish.
Eel passage testing at Natel headquarters in California
Close up of European freshwater mussel.
Featured Story

Why Safe Fish Passage Matters for Water Quality

Learn about the surprising and critical relationship between clean water, mussels, and fish passage in hydropower. This article by Director of Communications and External Affairs Kate Stirr was featured as the lead story in the NHA's POWERHOUSE publication.

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Map showing range of critically eimperiled and imperiled pallid sturgeon in the US

NatureServe. 2010. Digital Distribution Maps of the Freshwater Fishes in the Conterminous United States. Version 3.0. Arlington, VA. U.S.A.

Pallid Sturgeon Passage
and FishSafe Hydropower

Natel prepared an evaluation of design options to improve conditions for migratory passage of pallid sturgeon at the Lower Yellowstone Diversion Dam. The primary goal of the project was to improve river connectivity through safe, efficient, and timely upstream and downstream passage for pallid sturgeon at all stages in their lifecycle. The existing diversion dam featured a rock ramp with a steep slope, which resulted in high water velocity and shallow depths under certain river flow conditions, which was largely impassible for sturgeon.

Natel studied two alternative designs to replace the existing channel-spanning ramp: (1) a new channel-spanning low-gradient simple rock ramp, and (2) a new stepped ramp incorporating large resting pools. Both alternative designs allowed for substantially reduced water velocity and increased water depth, improving the feasibility of sturgeon passage. Natel created a multiphase 3D CFD model of the stepped ramp, which enabled a detailed assessment of velocity distributions around the facility.

Natel also evaluated the possibility of implementing a run-of-river hydropower facility, incorporating turbines that would allow for safe downstream passage of juvenile sturgeon. The proposed hydropower facility could generate at least 11 GWh annually, and revenue from the facility could help offset overall project costs. This project would be an example of Natel's Restoration Hydro concept, in which restoration of river connectivity is acheived in conjunction with sustainable hydropower generation.

Close up of European freshwater mussel.
Featured Story

How FishSafe Turbines Can Help Re-Establish River Connectivity and Support Global Fisheries

Nearly half of the world’s fish species live in freshwater rivers, lakes, and wetlands, and freshwater fish account for close to half of all fish consumed by people globally. According to a 2016 UN report, global fish consumption has been growing steadily in the last 50 years — at double the rate of population growth — but at same time, the report found, we've been repeatedly choosing hydropower over ecosystem health. With FishSafe turbines, we don't have to make that choice.

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