Under the Clean Water Act Section 316(b) rule applicable to existing facilities (Rule) the U.S. Environmental Protection Agency requires permittees to achieve impingement mortality compliance by selecting one of several best technology available options provided in the Rule. One compliance method to meet this requirement is to install fish-friendly modified traveling water screens (TWS) and conduct a two-year Impingement Technology Performance Optimization Study (optimization study) to demonstrate that the TWS have been optimized to minimize impingement mortality. As it is presented within the Rule, this two-year field biological demonstration will pose many challenges for EPRI members to overcome in seeking impingement mortality compliance. A number of factors need to be considered throughout the process from as early on as TWS selection to obtaining approval of a study design to the final step of continued compliance with the permitting authority.
In anticipation of the Electric Power Research Institute (EPRI) membership’s need to meet the optimization study requirement at their facilities, EPRI established a TWS Optimization Program to investigate the factors, challenges, and level of effort potentially necessary to optimize a TWS for fish survival. As par of the program, ASA was contracted to develop a Technical Resource Report for EPRI membership to summarize the Rule requirements, provide the information associated with the optimization process, and identify challenges that may need to be overcome in implementing a field optimization study.
ASA researched and prepared a Technical Resource Report which presented the key components of a biologically effective optimization study and the challenges associated with implementing them. As the optimization parameters and methods selected are site-specific, this resource report is meant to serve as a starting point for EPRI membership in planning and implementing the requisite optimization study.