RIVER CHANGES IN RIVER LANDSCAPES

Main river landforms in upland areas are steep V shaped valleys, interlocking spurs, waterfalls and gorges. They have all been formed by the erosion, weathering and mass movement

In uplands:

• The long profile is steel and the river flows fast

• Processes of hydraulic action and abrasion erode the river bed and make the valley deeper. There is mass movement of material

• The valley floor is narrow and often occupied by the river

Interlocking spurs are formed where the river swings from side to side

Waterfalls occur where a band of hard rock is much more resistant to erosion than the softer rock below it. The falling water excavates a plunge pool at the bottom. The hard rock is eroded back by the river and the waterfall retreats upstream leaving a gorge below it

When the river leaves the upland and flows across lowland, the river channel becomes wider and deeper. Because of this, the velocity and the discharge continue to increase

The valley cross-section is wide and flatter. The floor is occupied by a flood plain. Near the end of its course the floodplain spreads out to become whether a delta or and estuary

During the river’s lowland course, vertical erosion is less important because the river is too close to sea level. Lateral erosion is where the river wears aways sides of the channel, especially on the sides of meanders. Once the river loses energy, it drops some of the load on the flood plain. 

Everytime the river leaves it’s channel, the velocity decreases

The largest amount of deposition is always on the banks of the channel, which build up to a greater height than the rest of the floodplain to from levees