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The Drainage Basin |
 The Drainage Basins Worksheet |
| The Concept of a Drainage Basin | |
| A drainage basin is an area of land drained by a river and its tributaries. All of the earth's land surface is covered by drainage basins. | |
The 14 Major Drainage Basins in England and Wales. |
The Mississippi Drainage Basin, USA. |
 Major Watersheds of the World |
A system can be defined as any set of interrelated components or objects which are connected together to form a working unit or unified whole. In geography it is usual to recognise two general types of systems: closed and open. |
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Watershed |
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Catchment Area |
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Tributary |
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Confluence |
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Source |
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Mouth |
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Floodplain |
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This is found by measuring the total length of all the streams within a drainage basin and dividing by the area of the whole drainage basin. It is therefore the average length of stream within each unit area. The following factors influence drainage density:
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| Stream Order |
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Unbranched source tributaries are called first order streams. When two first order streams join they form a second order stream; when two second order streams join they form a third order stream; and so on. It requires two streams of equal order to join to produce a segment of a higher order. A drainage basin may therefore be described in terms of the highest order within it. For example the drainage basin in the diagram above would be a 'fourth order basin'. |
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| The ratio of number of streams of a particular order to number of streams of the next highest order. It gives an expression of the rate at which a stream network bifurcates. |
| Note: Refer to page 66 in Geography An Integrated Approach, David Waugh, Third Edition. Excercise on page 98. |
Bifurcation within a human aorta. |
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Geofile 366 - January 2000 - Case Study of a Drainage Basin - The River Ouse, Yorkshire.
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IB Geography - Drainage Basins and their Management Links |
If you find any revelant geography websites - please email a link to Richard Allaway |
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