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FishSafe™️ turbines can be a transformative first step to improve river connectivity, by allowing fish to travel directly downstream. When combined with nature-based engineering techniques used for river restoration, FishSafe™️ turbines can be part of a holistic solution that restores degraded waterways and provides reliable, renewable power.
The RHT name suggests the intent of this design family—to create turbine runners that can be used to support river restoration, by enabling through-turbine downstream passage for aquatic organisms.
Natel's Restoration Hydro development approach couples hydropower production with river restoration. FishSafe™ RHTs maintain or improve river connectivity by enabling fish and sediment to travel with the bulk of a river’s flow—directly through the turbine. Retrofitting non-powered dams and upgrading existing hydropower plants with FishSafe™ RHTs can open up new downstream passage routes, restoring connectivity in previously fragmented rivers.
By combining FishSafe™ RHTs with engineered structures that mimic naturally-occurring features of a river like beaver dams and rock arches, Restoration Hydro can stabilize eroded river banks, restore habitat, enhance groundwater recharge, reduce flood and drought risks, and improve water quality—all while generating reliable, renewable energy.
With support from the United States Department of Energy (DOE), we worked with researchers at Oak Ridge National Laboratory, river restoration experts at Natural Systems Design, and recreational designers and engineers at Mclaughlin Whitewater—as well as others from the University of California, Berkeley’s Environmental Systems Dynamics Laboratory, Small Hydro Consulting, and Wells Engineering—to apply the principles of Restoration Hydro to a paper demonstration site in Virginia, United States.
The conceptual partial dam removal project would provide meaningful restoration outcomes including reconnecting 137 miles of upstream habitat for migratory fish (eel, shad, striped bass, river herring) and improved sediment transport, while replacing a recreational hazard with a world-class surfing facility — all while delivering 2.4 MW / 13 GWh of FishSafe™ hydropower and replacing ~50% of the existing dam with a rock arch that would enable upstream fish passage.
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 Natel RHT-style turbines that would allow 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 achieved in conjunction with sustainable hydropower generation.
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.
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.
