Comparison of juvenile white sturgeon survival through a conventional and a novel hydropower turbine

Hydropower is a globally important renewable energy source with profound
impacts on aquatic organisms, including direct injury and mortality to
fish that move through hydropower facilities. While it is expected that
the characteristics of turbine design and operation influence the type,
frequency, and magnitude of injuries suffered by entrained fish, few
direct comparisons exist to illustrate differences in fish survival
outcomes for conventional and novel turbine designs. This study evaluated
injury and mortality rates for juvenile white sturgeon (Acipenser
transmontanus) passed through a model-scale turbine equipped with a runner
having conventional blade profiles (thin, straight leading edges) and the
same turbine equipped with a runner designed for improved fish survival
(thick, slanted leading edges). In both trials, head and turbine runner
rotational speeds were matched to produce five blade peripheral speeds
between 15.0 and 27.6 m/s. High-speed video was captured for all turbine
passage events. Fish were assessed for injuries following passage, and
mortalities were assessed immediately after passage and after 48 hours.
Conventional runner passage resulted in 42% to 78% survival after 48
hours, with approximately one-third of all tested fish killed by severing.
Under the same test conditions, immediate and 48 h survival rates through
the novel runner were 100% except at the highest speed condition (95.6%
survival at 48 h). These results clearly indicate that turbine design has
a profound effect on fish survival outcomes, and suggest that thoughtful
redesign of hydropower equipment could significantly elevate fish survival
rates.