Screen apparatus

Screen apparatus comprising a channel (20) along which fluid flows, a screen (10) which allows fluid to pass through it whilst providing a barrier to non-fluid matter in the fluid characterised in that said screen is positioned adjacent said channel to extend along a portion of said channel between ends of said screen such that during overflow conditions a portion of said fluid overflowing said channel is directed onto said screen while said screen remains in communication with said channel such that said matter entrained in said portion of said fluid is returned to said channel during said overflow conditions, the apparatus further comprising a jet outlet (22) located at one of said ends of said screen and arranged to direct a jet of fluid across that side of the screen (10) on which such matter would otherwise tend to collect toward the other of said ends during said overflow conditions.