I think this is a very interesting question. who will clean the channels? some will say that we will have developed robots and AI to be able to do all of the labor we don't like that much. Another point is that we will pay this kind of jobs very well - which we should. Like picking up the trash is way more important for society as a whole than a brain surgeon - well, until we all get it that producing as much trash as we do is not sustainable and figure out a zero waste lifestyle.
The other possibility is that people with enough social consciousness will do the cleanup work since it is something which needs to be done - kind of like cleaning the toilet - or cleaning period. Like I don't like cleaning at all but I do it because the alternative is worse.....