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1 Typical Disadvantages Effectiveness for repelling salmonids is unknown; data is needed for those species There have been design and operational problems with experimental underwater strobe systems The field testing to date has been limited so that success is unknown ' Application to Limiting Downstream Passage. Light systems are generally used to either deter fish from a spillway or intake area or direct them toward a bypass area. In both applications on this project, that would require fish handling if the fish are directed to a fish bypass area. In addition, several species have been shown not to be affected by the light systems and the light systems ' currently have limited application in daylight hours. This would effectively not deter fish at all times as the criteria for this project are designed. 1.3.7.4 Louvers ' Characteristics. Louvers consist of a series of vertical parallel bars spaced from 1 to 12 inches apart and the entire structure angled to flow across the entire channel. This physical device relies on the fish's behavioral response to flow turbulence. The fish approach the louver system tail first, ' sense the turbulence created by the louvers and move laterally away from the device. This movement directs them to the bypass area. Typical Existing Application. Louvers have been installed on both the east and west coast rivers. Installed facilities include canals with widths up to 145 feet and maximum capacity of 7,000 cfs. Guidance efficiency ranged up to 87% of downstream migrants in some applications for actively swimming life stages. In general, guidance efficiency was less than 80%. Louvers did not ' effectively guide smaller life stages and are not effective on passive life stages. Typical Advantages • Louvers are adequately tested • Louvers can be retrofitted in many designs ' Typical Disadvantages • Diversion efficiency lower than agency standards in some applications • Louvers are size and species specific as far as guidance efficiency 0 Potential problems due to clogging arise at some locations • Louvers are relatively expensive. • Louvers require diversion of the fish and fish handling • Large openings do not exclude fish ' Application to Limiting Downstream Passage. Louvers are designed to guide actively swimming life stages. The current project includes potential escapement of passive life stages exiting the ' reservoirs. The effectiveness of louvers on passive life stages and the relatively low efficiency (less than 80%) preclude the use of this control option at the subject reservoirs. Control Structure Feasibility Evaluation 1-25 ' Miller Ecological Consultants, Inc., February 18, 1997