The Physical Characteristics of a River

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The Physical Characteristics of a River

Introduction:

River Features are elements of the landscape produced by fluvial

processes-that is, the action of running water as it flows through the

channels forming the drainage network of a river basin, eroding,

transporting, and depositing sediment. (Source from Microsoft Encarta

Encyclopedia 2001)

A useful way to study a river is to look at its long profile and its

cross sectional profile. The long profile of a river is a section

drawn along the length of a river from its source to its mouth.

Usually, a long profile has three parts:

â— Upper course or mountain tract

â— Middle course or valley tract

â— Lower course or plain tract

However, in Hong Kong most of the rivers are short and their gradients

change abruptly. These rivers have two courses only, the upper and

lower courses. Not all rivers have three well-defined stages. Some

reach base level direct from stage 1 (Base level is the lowest level

down to where a river can erode). Others arise amid lowlands. The

diagram below shows typical changes in the river channel:

[IMAGE]

The table on the next page lists out the features produced by river

processes in each course.

The Long Profile of a River

Upper Course

Middle Course

Lower Course

* V shaped valley

* Steep gradient

* Vertical erosion

* Flows between interlocking spurs

* Flood water rises high in valley

* In flood, river moves boulders

* Small discharge

* Small boulders help to wear bed and banks

* Load more angular and larger

* Pebbels wear potholes in bed

* Uneven ...

... middle of paper ...

... which to adjust to the average flow of the river.

Whereas a shorter distance will only give the orange peel a small

amount of velocity. There is more chance of the reading of velocity to

be affected if it is taken in shorter distance as a tributary could

effect the amount of water flowing at that particular place whereas

the flow of the river is averaged out more over a longer distance.

Bibliography:

Chinese International School Geography Department Website:

http://www.cis.edu.hk/sec/ss/Geography/IGCSE/INDEX.html

World Wild Fund for Nature Hong Kong:

http://www.wwf.org.hk/eng/conservation/hab_protect/green_dragon/hoi_ha_wan.html

Text Book - New Geography 4A

Text Book - The New Wider World by David Waugh

Microsoft Encyclopedia Standard 2001 - WE

IGCSE River Investigation Field Guide 2001

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