Features of erosion
- 1. Features Of Erosion By Jesse, Abdullahi, John, Nderitu and Angela. 1
- 2. Waterfalls • Waterfalls are usually formed when a river moves over resistant bedrock and erodes it slowly while downstream it happens faster. • As this happens material is plucked from a river bed which causes the waterfall to carve deeper into the riverbed and recede upstream • part of the bedrock (hard rock) will later break off, exposing the soft rock, and form a waterfall. • The rest is in the diagram on your right 6/6/12 Group Y 2
- 3. OX BOW LAKES • An ox bow lake is a U - shaped water body or meander that is cut of by erosion to form a lake. • They are formed when a river has a very curve us meander, which is nearly meeting the other side of the river. • Due to erosion and deposition the neck of the meander becomes very narrow which allows water to pass straight, flowing past the old meander. • Deposition then occurs, sealing of the meander. • The deposition then totally covers up the meander so no more water can pass. • Over time the closed meander completely cuts of from the rest of the river. • The end result is a straight river separated from a curved C-shaped lake. 6/6/12 Group Y 3
- 4. OX BOW LAKES 6/6/12 Group Y 4
- 5. V-shaped valleys. • In the upper course of a river, water flows at a high speed through a narrow channel with a steep gradient. • As it does, so it cuts downwards. • This vertical erosion results in a number of distinctive landforms including, the steep sloped v- shaped-valleys • Through this the river flows in it's upper course. 6/6/12 Group Y 5
- 6. Formation of v-shaped-valleys. • Vertical erosion leads to the development of steep sided, narrow valleys shaped like the letter V. • The valley sides are steep due to the soil and loose rock being washed downhill following periods of heavy rainfall. • The material is then added to the load of the river. • The river itself forced to wind its way through protruding hillsides. • These hillsides known as interlocking spurs restrict the view up or down the valley. 6/6/12 Group Y 6
- 7. RAPIDS • A river rapid is a section of a river with a steep gradient, which cases an increase in the water velocity and the turbulence. • A rapid is caused by the river becoming shallower and having some materials, like rocks, to be exposed above the flow surface. • In rapids, water turns white because flowing water splashes over and around the rocks, and air bubbles mix with them. • This colour is normally called “White water”. • Rapids normally occur when the river bed is highly resistant to erosion. 6/6/12 Group Y 7
- 8. Rapids • Rapids are categorized into several classes: • Class 1- This is when the river has small waves in fast flowing water and has very few obstacles, e.g. rocks. • Class 2- When the river has wide channels and rapids , without many turns and obstacles. • Class 3- This class has strong currents with many obstacles in the river. • Class 4- Powerful rapids with big waves • Class 5-Very violent and dangerous rapids with tight turns • Class 6- This last stage is the most violent and strong. This rapid can cause death easily. 6/6/12 Group Y 8
- 9. Rapids • Many people use these river rapids to have fun. • Rafting, is a sport which requires rapids. • Rafting courses are also classified using these rapid classes. 6/6/12 Group Y 9