All about rivers!

SUP 03!

As you all already know, IS2104 this term is about the HYDROSPHERE. As such, we are learning about 2 very important and crucial branches of the hydrosphere, (1) the Hydrological Cycle, and (2) Rivers.

Marie has done a post on the hydrological cycle already, so today I am going to give you a recap, and list the main points on what we learnt about rivers, to make your future studying easier. (:

Firstly, there are 4 different parts of the river.

Secondly, rivers have 2 main functions:

1. Transport water

2. Transport load (sediments)

The velocity of the river flow affects the amount, and size of particles being transported. A river with a high velocity tends to disturb and transport large particles, while a river with low velocity does not disturb sediment on the river bed, and tends to deposit sediments

Thirdly, there are 3 stages of rivers:

1. Youthful ( upper course)

2. Mature (middle course)

3. Old (lower course)

The 3 courses of rivers are quite distinct. Here are their unique traits:

	Upper course (youthful)	Middle course (mature)	Lower Course (old)
Gradient	Steepest	Not as steep	Gentle
Velocity	Highest	Not as high	Low
River channel	Small, narrow, rough, shallow	Wider, deeper	Widest, deepest
River valley	Deep, narrow, steep-sided (V- shaped)	More open V-shape, wider floor	Wide, flat-bottomed
Erosion	Mainly vertical (lateral negligible)	More lateral (less vertical) > form meanders	Lateral erosion on concave banks (vertical almost stopped)
Main work	Overcome friction in rough channel	Some deposition, some erosion	Deposition
Examples (occurrences)	Appalachian mountains, Himalayans	River Nile, Sebaskachu River, River Taff, River Thames	Ganges, Nile, Euphrates
Landforms	Waterfalls, rapids Canyons, arches, gorges, plunge pools	Meanders, oxbow lakes	Floodplains, levees, oxbow lakes, deltas

Rivers alter landscape through erosion and deposition, creating many different landforms. To note,
Erosion = removal of material
Deposition = depositing material

So yup, there you go, the main points about rivers. Yi Jin will go through more about erosion, deposition, and river landforms in the next post!

P/s. Try to distinguish the different types and courses of rivers when you see them in Pulau Ubin! (:

♥, Ai Lin (14)

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By the way, do you know that the drainage patterns of rivers are also affected by plate tectonics? (Converging and diverging plate boundaries stuff we learnt last year.) So cool right? Visit http://blue.utb.edu/paullgj/geol1403/lectures/river_systems.html to find out more! :D