4 processes of river erosion

November 12, 2025

The following are the process involved in the river erosion:

Hydraulic process - this is the eroding force of the water on rocks. This takes place when the force of the river water surges into cracks or sweeping against banks on the outside of bends with turbulence and eddying. It erodes through quarrying or scooping by water force.

The corrosion/abrasion process - this takes place when the materials scooped out by hydraulic action corrodes (abrades) the river bed by swirling fragments in the hollow to form potholes.
The attrition process - this process - involves reducing the size of materials transported by river by knocking against each other, through frictional rubbing and grinding as they are transported.
The solution process - this process occurs when the river passes in areas with rocks like limestone which can be eroded when they react with acids.

FEATURES RESULTING FROM RIVER EROSION

V-shaped valleys
Waterfalls
Rapids
Interlocking spurs
Plunge pools
Potholes
Gorges

V-shaped valleys

These are valleys in the upper course of the river that have been undercut by vertical erosion. The rocks in the bed are always softer than the side rocks hence promoting more vertical erosion than lateral erosion. This results into the formation of a narrow V-shaped valley. Best examples can be found on river mubuku, Nyamugasani all on mountain Rwenzori.

Waterfalls

A waterfall is a sharp break in the river channel’s bed over which the river flows. It’s found in the youthful stage of the river. It can be formed where vertical or horizontal bands of hard and soft rocks lie across the river bed. The soft rocks upstream are protected by the vertical band of the hard rocks across the river bed. The soft rock downstream is in low in height therefore forming a waterfall eg sezibwa falls near lugazi and sipi falls on river sipi in kapchorwa.

A rapid

If the band of a hard rock is steep or slanted across the river bed but not vertical, then a rapid will develop eg at bujagali

Plunge pool.

This a broad depression formed at the base of a waterfall or an enlarged pot hole formed due to progressive drilling and grinding of the valley floor. Its formed on rivers with valleys in the youthful stage pf a river. The conditions necessary for the formation of a plunge pool include;

A large volume of water
Great erosive power of the river due to the steep gradient.
The availability of the load being carried by rivers which act as a grinding tool of the surrounding rocks (abrasive media)

In its formation, falling water from a cliff cuts pot holes at the base of the waterfall. Then strong eddy currents swirling and erosion collectively enlarge potholes to produce plunge pools.

Best examples are at murchission falls, sezibwa falls, sipi falls in kapchwora and kisizi falls in Rukungiri.

Interlocking spurs

Interlocking spurs are termed as river twists and twins around obstacles of hard rocks along the channel. This results into the river taking a winding course. In the bends, there is more erosion on the concave banks which eventually causes projections of highlands called spurs. They alternate on either sides of the river to interlock hence they are called interlocking spurs.

Gorges and canyons.

A gorge is a steep sided hollow in depth as compared to its width. A river gorge is found where fluvial erosion cuts more rapidly than the forces of weathering can wear back and opens up the sides. Gorges can also occur where a river follows lines of weaknesses eg a fault line hence the river cuts vertically deeper into the rock than the sides hence creating a deep steep sided valley into which a river flows.

A gorge can also be formed in resistant rocks where there is vertical erosion in the center of the river valley so that the sides stand up steeply. Best examples can be seen at kyambura gorge in Queen Elizabeth national park, at Murchison falls on the Victoria Nile as it enters lake albert and the great Rucha gorge in Tanzania.