Niyodo River in Shikoku. Here is one of my favorite places in Western JAPAN. I come to this river with my dog "Hana" in every summer to enjoy camping and swimming. The stream is very strong and deep. There is the depth of the water more than 10 meters in the deepest place. I really love this location.
Video : A summer vacation of Hana - Hanaのなつやすみ You can watch the dog paddling in the water:)