Alden turbine

Alden turbine 

One of the newest improvements to fish passage technology comes through development of an innovative runner concept by Alden Research Laboratory. The Alden Turbine features a slower rotational speed and only three blades to reduce fish mortality due to blade strike. Voith Hydro has optimized the final design and tested it at their hydraulic laboratory in York, Pennsylvania (USA).

The blade shapes are specifically designed to improve the fish passage environment through the turbines by minimizing shear, pressure change rates and minimum pressures within the water passage. Depending on the species, full-scale fish survival rates are expected to range from 98% to 100%.

Through funding made available by the DOE, EPRI and industry partners, Alden Research Laboratory collaborated with Voith Hydro to improve the performance characteristics of the conceptual turbine while maintaining or improving the fish-friendly characteristics. The partnership also focused on ensuring the turbine’s cost-effectiveness while maintaining improve- ments in fish survival rates.


Key benefits include a reduced strike probability by optimizing the number of turbine blades, wicket gates and stay vanes as well as improving the hydraulic profile of the turbine components and the rotational speed. The turbine also features optimized water passage geometries to meet specified fish passage criteria.