Can you enter the water? I saw people swimmimg in the river, but I can swear it's against park policy? I know back in the mid 90's people were always in the water. Up until all the drownings etc

I would also agree, there are signs telling you not to go in but it's for your own safety.. some people have died by simply going under the water and having bacteria form in their brain due to water going up their nose, do not go into the water

No, its not legal

I wouldn't: whether it's permitted or not. The water is dirty and has a bad odor.