Swimming spots in Shikoku

Am doing 6 days driving around Shikoku in Sept from Matsuyama-Kochi-Takushima. Going to drive by so many rivers but just wondering whether you can swim at some of the many waterholes, waterfalls? I know certain ones are sacred with no swimming, but for others is it ok to swim providing they are safe? Any recommendations on awesome natural spots would be appreciated!

by little_mighty3031