fish entrainment and impingement
Industries use large volumes of surface water for cooling purposes or to make potable water. In the process, their (cooling) water intake structures may draw in large numbers of fish (entrainment), which can block intake screens (impingement). Unfortunately, impingement and entrainment can injure and/or kill fish. In addition, impingement can reduce or stops the flow of cooling water and may result in a facility shutdown, major downtime costs and adverse environmental effects.
Companies usually try to protect fish by using physical screens to prevent them from entering the intake. However, as a supplement to physical screens, behavioural guidance technologies can also serve as effective fish barrier. Behavioural guidance systems stimulate the natural instincts of fish to guide them away from a stimulus. Acoustic systems are the most widely used behavioural technologies and are suitable for deflecting migrating fish, resident coarse fish, and estuarine and marine fish.