Book contents
- Frontmatter
- Contents
- Preface
- Part I The Tropical Environment
- Part II Process geomorphology in the tropics
- 5 Weathering in the tropics
- 6 Slopes: forms and processes
- 7 Rivers in the tropics
- 8 Alluvial valleys
- 9 Large rivers in the tropics
- 10 The tropical coasts
- 11 Deltas in the tropics
- 12 The arid tropics
- 13 Tropical highlands
- 14 Volcanic landforms
- 15 Tropical karst
- 16 Quaternary in the tropics
- Part III Anthropogenic changes
- References
- Index
- Plate section
7 - Rivers in the tropics
from Part II - Process geomorphology in the tropics
Published online by Cambridge University Press: 05 February 2012
- Frontmatter
- Contents
- Preface
- Part I The Tropical Environment
- Part II Process geomorphology in the tropics
- 5 Weathering in the tropics
- 6 Slopes: forms and processes
- 7 Rivers in the tropics
- 8 Alluvial valleys
- 9 Large rivers in the tropics
- 10 The tropical coasts
- 11 Deltas in the tropics
- 12 The arid tropics
- 13 Tropical highlands
- 14 Volcanic landforms
- 15 Tropical karst
- 16 Quaternary in the tropics
- Part III Anthropogenic changes
- References
- Index
- Plate section
Summary
The moisture-laden wind blows at speed
Awakening the mad river
Rabindranath Tagore,
translated from Bengali
Components of a river system
Rivers are conduits for transferring water and sediment from the land to the ocean. Among the multitude of factors that control their dimensions, appearance and behaviour, four are of high importance: water, sediment, sediment texture (grain size) and channel slope. If any of these changes, the river can be expected to accommodate the change with a proportional shift in its form and function. To illustrate, other factors being equal an increase in the supply of sediment would lead to deposition in the channel. However, if the increased sediment simultaneously becomes finer, the river may be able to transfer most of the fine sediment downstream. In contrast, an increase in stream flow due to rainfall from a large storm or tectonic tilting of the channel slope may lead to erosion. This relationship (Fig. 7.1) was expressed in a simple diagram by W. M. Borlaug based on an equation derived by E. W. Lane (1955). We need to explore these factors in order to understand rivers.
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- Information
- Tropical Geomorphology , pp. 101 - 128Publisher: Cambridge University PressPrint publication year: 2011