The AWMA Fish Exclusion Screen is basically a large filter (like a sieve). The filter has slot sizes from 1mm to 3mm that prevents all stages of fish life from entering through the screen. Also turtles, as this little guy demonstrates.
AWMA’s self-cleaning fish screens have been installed widely throughout Australia and NZ. As such, this ensures, millions of native fish and other aquatic flora and fauna remain in the rivers to breed and thrive, instead of being extracted through irrigation and urban water diversions.