1.Geology resistant/less resistant rocks (ridges of hard rock create an uneven slope)
2. Remains of a waterfall
3. Remains of a knick-point
A rapid is a section of a river which has a relatively steep gradient leading to an increase in water flow and turbulence. It is a hydrological feature between a run (smooth part) and a cascade (a drop). It is characterized by the river becoming shallower and exposed rock.
The zambezi river where white water rafting is known as 'commercial suicide'. The main attraction is the 27km of gorge below the falls, a one day run.