Can you swim in the river

There is an ordinance that says you aren't supposed to swim in these type waterways, but it isn't really enforced. That said, almost everyone is respectful of this special resource. If people start swimming too much, littering or overall not being cool, that will change.

There are signs everywhere along the river that say " stay in your vessel"...but everyone swims...

Yes, you can swim in river where you kyak, but motor boats use same access. There is a park on the river with roped off swimming

Yes. It's cold, but ues!

Swimming area is ropped off. There is a platform and lifeguards. You can rent tubes to go into what they refer to as lazy river.