Laboratory Traveling Water Screen Optimization Evaluations

If traveling water screens (TWS) are selected for impingement compliance under the final Rule a two-year biological optimization evaluation will be required at each facility.  EPRI has undertaken an optimization program to demonstrate which TWS components are appropriate for optimization and the challenges associated with gathering such data in the field at Alabama Power Company’s Plant Barry. 

To supplement this on-going field optimization program EPRI has conducted laboratory evaluations to investigate optimizing TWS components and scenarios under ideal conditions with healthy hatchery fish to determine if a significant difference in survival can be detected.   The components and scenarios evaluated for optimization included TWS rotation speed (5 & 10 ft/min), fish spray wash pressure (10 & 20 psi), and investigating duration of impingement (5 & 10 min).  

High survival (>95%) was experienced for all species evaluated regardless of screen speed, spray wash, or duration of impingement condition.  Treatment survival was within a few percent differences of each other making it difficult if not impossible to detect a significant difference across component conditions.  These results and those from the EPRI field program are anticipated to provide the industry with information to aid in conducting successful field optimization TWS studies.