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1 ' movement. Electrical barriers, like all other behavioral devices, are considered experimental at this time and are not a standard application at downstream protection facilities. Typical Advantages ' • Successful in stopping upstream migrants 0 Lower cost for construction than standard physical screen • Useful in shallow canals or inlets • Used at locations with lower flow volumes Typical Disadvantages ' • Response to electrical field is species and life stage specific • Electrical barriers are not useful with passive life stages • Electrical field fatigues fish which then become entrained in the flow • Require multiple fields and multiple field strengths to deter a wide variety of size classes at one location • Main disadvantage: In the current application, there is a danger to humans and large animals that would fall into the field and be subject to electrocution. Application to Limiting Downstream Passage. Prevention of downstream passage has shown ' mixed results. The installation requires a shallow water depth and that it also is used usually in conjunction with other technology. They have been most successful in preventing upstream migration, not downstream migration. It also would require a secondary bypass once the fish are ' moved away from the spillway or outlet works. In previous applications, a DC electrical field has been used to stun the fish and move them into the bypass because of either stress or the inability of the fish to locate the bypass once they have been subject to the AC field for deterrence. This system ' could be used in conjunction with some other technology under the current projects but it is not as successful at preventing downstream migration as standard technologies. 1.3.7.2 Sound Characteristics. Recent work on sound systems has focused on both high and low frequency systems. Sound systems consist of speaker arrays to distribute sound through the water and speakers generally are mounted in underwater locations. Speakers are usually located underwater to deploy either sound such as natural predators or pure tones. Frequencies vary at each application. Sounds customized to each specie's hearing abilities are shown to be the most effective. This requires considerable research and experimentation for each specie to be deterred at the installed location. ' Typical Existing Applications. Sound systems have been experimentally evaluated in the northeast and midwest. Generally they consist of underwater speakers used at sluice gates such as the application that was investigated at Allegheny Reservoir, Pennsylvania. In this application, ' percussion type sounds were used at sluiceways. No change in fish passage through the sluices was noted during the experimentation. The target species at this location was walleye. Installation of a system at Racine Hydroelectric Plant on the Ohio River showed deterrence of 70% of the basses and ' catfish present at the intakes area of the hydroelectric plant. This system was a low frequency, high amplitude sound produced by a submerged generator. ' Control Structure Feasibility Evaluation 1-23 Miller Ecological Consultants, Inc., February 18, 1997