Theory question 305
Rivers and River Landforms(a) List three processes of river transportation. (b) State four characteristics associated with the middle course of a river. (c) With the aid of a diagram, describe the mode of formation of interlocking spurs.
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(a) Traction; saltation; suspension; solution.
(b) Gentler gradient than the upper course; wider, open V-shaped valley; lateral erosion becomes important; meanders begin to form; more volume of water from tributaries; deposition begins, forming small flood plains; river cliffs and slip-off slopes.
(c) Diagram: plan of a winding river between alternating spurs. In the upper course the river cuts downward rapidly (vertical erosion); it is too small and weak to erode sideways, so it winds round areas of harder rock; the projecting ridges (spurs) on alternate sides overlap one another and appear to lock together, so one cannot see far up the valley.
Stress vertical erosion.