Running water can simple be defined as the natural movement of water in a certain direction. Running water is the most powerful agent of water erosion.
Water erosion is the detachment and removal of soil materials by water. Water erosion wears away the earth’s surface.
Meaning of a River
A River can be defines as a large natural stream of water flowing in a channel to the sea, a lake, or another such stream.
Velocity of a River
The velocity of a river refers to the rate of water movement, often measured in metres per second. River velocity is determined by the efficiency of the river in overcoming friction with the bed and banks.
Factors affecting the Velocity of a River
1. Mean flow velocity of a river increases with distance from the source
2. The higher the volume of water released by a river, the higher the velocity, however as the volume decreases during dry period, the velocity also decreases
3. The steeper the slope, the higher the velocity of water in the river
4. A river uses more energy to flow through a flat – wide valley than through a narrow – deep valley because the former has a large surface area
5. The greater the speed of river, the greater the materials or loads it can carry or move
Processes of River Erosion
The erosive work of a river consists of four interacting processes which are:
• Hydraulic action process This is the ability of moving water (flowing or waves) to dislodge and transport rock particles.
• Corrosion – is the wearing away of the sides and floor of the river valley with the aid of sand, pebbles, silts and boulders which are being transported. These materials eventually widen and deepen the river valley
• Attrition – is the wearing down of the load as they collide with one another and with the floor and sides of the valley. Large boulders are broken down into small pieces like pebbles
• Solution – refers to the chemical action of water on materials it comes in contact with while flowing, rock salts are dissolved and carried away in solution
Processes of River transportation
The load of a river is carried or transported along four main processes, these are:
1. Solution: Some rock materials dissolve in water, and are carried in a solution from the upper to lower course of the river
2. Suspension: The lighter particles of solid materials are carried in suspension as the water flows
3. Saltation: In this process, larger particles are moved in series of hops or jumps along he stream bed
4. Traction: This involves very large fragments of materials being rolled or pushed along in the river
A river delta is a landform that forms from deposition of sediment carried by a river as the flow leaves its mouth and enters slower-moving or standing water. This occurs where a river enters an ocean, sea, estuary, lake, reservoir, or (more rarely) another river that cannot transport away the supplied sediment.
Importance of Delta to man
• Delta serves as recreational destination
• Delta provides good agricultural land for cultivation
• Delta serves as source of water
• Delta provides habitat for plants and animals
• Delta is also good for fishing
• Delta is equally good for petroleum mining
Types of Delta
1) Arcuate Delta: This consists of triangle-shaped deltas formed of sands and gravels.
2) Estuarine Delta: This is formed at the mouth of submerged rivers depositing down the sides of the estuary.
3) Birds foot Delta: Deposited material divides the river into smaller distributaries.
4) Lacustrine Delta: Formed when a river flows into a lake.
Importance of River to man
1. Rivers serve as a medium of transportation from one place to another
2. Rivers serve as means of generating generation of Hydroelectric power
3. Rivers provide water for plant and animal use
4. Rivers aid in the promotion of sport
5. Rivers provide employment (fishing) to many people
If you found this site and its content useful and relevant to you, support and help us keep the site running so we can continue to give you solid educational updates. Click here to donate now thanks.