That's great that they have the dog rest stops.
The rest of the day seems to have been pretty great as well. I didn't realize there were problems with the water quality where you are. I would be very afraid to even see what the water quality is here.. probably toxic as hell.
The rest dog stops are a neat touch and also having a water bowl available. I think this idea is sponsored by one of the dog food supplier brands. Sea water is definitely not great when it has raw sewerage flowing into it. I think the problem always existed but it was controlled by dredging and making sure the flow of water did not land back on the beaches and swimming area. These days that would seem like a waste of money to the government and the hope is it just vanishes instead.
oceans are actually really good at dealing with sewage, as gross as that sounds. Fish will eat almost any organic material. Doesn't mean I want to swim in it though.