Fishery regulations enacted by Germany’s federal states stipulate that the hydropower plant’s inlet screen must have clear gaps of 15-20 mm between bars. The gaps must be as narrow as just 10-12 mm in water bodies popular among salmon. Hydropower plant operators are not in favour of these requirements since fine screens allow less water through and reduce the head. The fish-friendly trash-rack - a fine screen made out of flanged sheet metal - proves that this does not have to be the case. This profile has unbeatable hydraulics and many customers are pleased to find out that performance improves despite the narrower gap between bars. The screen is also very fish-friendly - that’s why it has this name - thanks to the material used, the smooth and rounded surface, the low clear width and the low head loss at the screen rack. The fish-friendly trash-rack was developed by Hans Oppermann and the University of Kassel, and is protected by patent.