In article , Derek Moody
writes
I delivered a boat to Swansea about a year back* - first time I'd seen the
Marina/lock arrangements (built since my days at Swansea Uni) - what does it
do to runs in low water?

This matter has been a bone of contention for years. The fish pas was
too violent for salmon to even try to ascend - they have been seen
turning away and eventually going uo the Neath River. To encourage more
fsih to run, they've been opening the gates on "full flow" and thus some
more fish do get up river. It was commonly thought that salmon
over-topped the barrage at high tide, but at the very top of the barrage
you get an up-stream water fall and the fish have been observed turning
back against the upstream flow.

The University carried out a project to monitor the fairly recently
modified fish pass but we don't think much has come of this research.

--
Bill Grey