river run
/ˈrɪvə ˌrʌn/noun
1The route which a journey by river follows.
2Specifically. A journey down a fast-flowing river in a small craft (as a raft, rubber dinghy, canoe, etc.), now usually for recreation.
3Usually in form riverrun. The course which a river shapes and follows through the landscape.
Origin
Mid 19th century. From river + run.