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.


Acoustic deterrent system


The Acoustic deterrent produces underwater sound, in order to deter fish from potentially hazardous areas, such as inlets for cooling water of industrial facilities. The required frequency is tailored to local fish species.

The Acoustic deterrent consists of: 

  • A Sound Generating Unit
  • A speaker unit (with Sound Transducer and Listening Hydrophone) & cables


H2O works together with partners in respect to fish and mammal deterrent systems for industrial surface water intakes. We provide acoustic systems to deter fish and sea mammals (e.g. porpoises and sea turtles). The systems are used for various purposes