Modern Approach to Estimating Impact on Aquatic Populations from Entrainment at Hydroelectric Facilities.

Nebiolo, Kevin P.¹, Alice Shelly², ¹Kleinschmidt Group, Essex, CT, ²Kleinschmidt Group, Redmond, WA

As fish migrate past hydroelectric projects, they risk becoming impinged on trash racks or entrained into the powerhouse where they can be struck by machinery. Both the probability of getting struck by a turbine runner blade and the rate at which fish are entrained (fish / Mft3) are well studied phenomena. However, until now they have yet to be combined into a risk analysis framework capable of assessing impacts to aquatic populations. The proposed Fish Entrainment Risk Assessment method or FERA combines empirical data that estimates entrainment rates (EPRI 1997) and numerical models that estimate blade strike (Franke et. al. 1997) into a Monte Carlo framework capable of estimating the magnitude and frequency of mortality events. FERA then assesses population resiliency using commonly reported doubling rates from reliable sources, e.g. FishBase.org or the Environmental Protection Agency. We hope that FERA becomes a tool for resource managers when designing fish protection measures at hydroelectric facilities.