For the September 2019 river cleaning SusWoT went to the Trym Valley in Southmead. The grills pictured above are at the Doncaster Road end. Any rubbish that is too big to pass through the Grills is trapped and eventually the Grill is pretty much blocked. This is why rubbish gathers all aroung the grill.
Clearing away all the rubbish is very satisfying as the Trym can flow through the grill more quickly into Badock’s wood and down to the Avon for a few months before it becomes blocked again.