finally got some photos together of a water wheel restoration & associated launder,valve & fish screen,of a hydro project ,it's been running a few years now ,so has settled in ,however it's worn a gearbox out (1:240 iirc !) & the designer since improved efficiency by fitting a more sensitive auto guillotine gate at the top of the launder.its been generating electricity all the time there's enough water in the brook,about 7/8 months.