Hydrographs
Hydrographs show how a river handles extra water volume as a result of increased rainfall. It shows how quickly water falling within the river basin will reach the river channel. There are several elements to a hydrograph:
BBC Bitesize has some info on hydrographs.
BBC Rivers – hydrography looks at factors affecting the shape of hydrographs.
Hydrographs will be effected enormously by a whole range of different conditions. What kind of effect would these conditions have on a hydrograph?
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small or large drainage basin? |  |
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impermeable rock (granite, clay) or permeable rock (limestone, sand)? |  |
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human activity – plantations or urbanisation? |  |
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vegetation – farmed fields or forest? |  |
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shape of the valley – steep sided or sloping gently? |  |
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prolonged, heavy rainfall or sudden showers? |  |
This keynote on hydrographs will also be helpful.
Floods
The IB Geography syllabus requires you to be able to ‘discuss the natural and human causes and consequences of a specific river flood.’
The command word discuss requires you to ‘offer a considered and balanced review that includes a range of arguments, factors or hypotheses. Opinions or conclusions should be presented clearly and supported by appropriate evidence.’
Take a look at this great interactive animation of flooding and associated concepts:
We’re going to look at the 1998 Bangladesh floods, and use what we find to structure a case study of the flooding which took place in 2012.
These news articles from 2012-13 highlight the causes and effects of the flooding.
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Presentation: Bangladesh flooding
Bangladesh in the front line of Climate Change?
Bocastle flood – BBC News looks at before and after (2014)
The Bocastle river flood from the RGS
New flood defence scheme at Bocastle
Bocastle: Then & now (floodblockbarrier.com)