More photos from my visit to the UK:
The verb ‘discharge’ would surely only apply to liquids or gases – effluent, not ‘litter’ – which doesn’t make much sense for a sign on a small, self-contained pool around an urban fountain. Where’s the Campaign for Plain English when you need them? (And, yes, I know I’ve mixed singulars and plurals there, but I don’t think it makes the sentence difficult to understand.)
That wasn’t the only sign on the fountain:

This may be true. It may also explain why so many small boys instinctively shy away from bathing. Has anyone done any tests to see whether small girls run less risk from water? In the same way that females appear to actually be ‘hard-wired’ to prefer pink, perhaps boys’ refusal to bathe is caused by biological programming.

I should say that the fountain itself was really quite attractive, even if the people who ordered the signs for it seem to have been advocates of modern gobbledegook and the nanny-state mentality.
Here’s a rather fine winged lion who was supporting the central water jet with, I think, three others of his kind. I thought at first he was a gryphon, but they usually have the heads of eagles on the bodies of lions, so perhaps he’s just a flying feline.