The Main Types of River Landforms
A river landform is a geographical feature which is formed when water moves on the earth’s surface. Geologically, water movements are the most essential external processes that can shape the earth’s surface. There are different types of river landforms and these vary in terms of size, shape and even formation processes. The following are some of the major landforms that have been formed through the flow of water:
- These are small, medium sized or large depressions that are formed on the earth’s surface when water flows on the upper course of the river, eroding soil on certain parts of it. Potholes can be a few centimeters or meters wide in diameter. They also vary in depth and are mostly formed when the water flows in turbulent currents against the bed loads on the upper course of a river. This causes the flow to swirl in eddie currents resulting in small depressions on the river beds. Such depressions result in potholes when pebbles fall into them, causing them to widen in depth and diameter.
- Waterfalls form when there is a change in lithology of the riverbed. This happens when the rock on the riverbed changes from resistant to less resistant making the less resistant riverbed susceptible to erosion. When the river flows on the weaker riverbed, it erodes it and this forms a sharp gradient in the flow of the river. The resistant and stronger remains high above while the less resistant rock drops a gradient below and hence the flowing water creates a plunge pool which is called a waterfall.
- These river landforms are formed when water from a river connects to another `point with lower velocity. They are mostly formed at the mouths of the rivers. Deltas are usually depositional landforms and occur when rivers flow into lakes or seas which are have low velocity and tend to be quiet and still water bodies. When the velocity of the river reaches the sea, it slows down and leaves deposits from the river flow at the point of connection. Most of the deposits are made up of three layers. Deltas come in three different types and this is dependent on the size and shape of the depositional landform. Arcuate deltas are formed when a river meets with a sea which has alternating currents. It is triangular in shape and an example of this is the Nile Delta. The Cuspate deltas are more or less v-shaped with curves on the wider edges. These are formed when a river meets with a sea which has a current and deposits are thus sent into the edges. An example of this type of delta is the Ebro Delta in Spain. The last type of delta is the Bird’s foot delta and this is rare because it is formed when a river’s current is stronger than the sea currents. The result is that deposits are spread out widely.
There are many other types of landforms which occur as a result of rivers flowing on the earth’s surfaces. Some of the more common types of river landforms not discussed above include:
- V-shaped Valleys
- Floodplains
- Rapids
- Oxbow Lakes
- Meanders
- Levees
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References
http://geographyas.info/rivers/river-landforms/
http://thebritishgeographer.weebly.com/river-landforms.html