Causes of the River Derwent Flood, 2009
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The causes of the 2009 flood in the River Derwent, Cumbria Use the following presentation to help you complete annotation onto the outline diagram in your notes. Physical causes are shown in blue, human causes in red. Colour code your annotation accordingly. The causes of the 2009 flood in the River Derwent, Cumbria
description
The human and physical factors that caused the flooding of the River Derwent in 2009.
Transcript of Causes of the River Derwent Flood, 2009
The causes of the 2009 flood in the River Derwent, Cumbria
Use the following presentation to help you complete annotation onto the outline diagram in your notes. Physical causes are shown in blue,
human causes in red. Colour code your annotation accordingly.
The causes of the 2009 flood in the River Derwent, Cumbria
NorthWorkington
Cockermouth
Cumbrian Hills
R. DerwentR. Cocker
Keswick
The various locations mentioned in your notes.
NorthWorkington
Cockermouth
Cumbrian Hills
R. DerwentR. Cocker
Keswick
1. Physical Causes
North
1. Warm, very moist air, blowing from the SW, meets Cumbrian mountains & is forced to rise.
North
2. It cools & condenses, producing cloud & rain – a lot of rain.
In fact, 400mm of rain falls, breaking the previous record for highest 24 hour total in the UK of 316mm.
North
3. There is too much rain to infiltrate into the ground, and so it flows by overland flow to the streams, causing their discharge to rise very quickly.
These feed quickly into the main rivers, the Derwent & the Cocker, increasing their discharge.
North
These feed quickly into the main rivers, the Derwent & the Cocker, increasing their discharge.
3. There is too much rain to infiltrate into the ground, and so it flows by overland flow to the streams, causing their discharge to rise very quickly.
Example of the extreme overland flow produced by the record-breaking heavy rain that fell.
Example of the extreme overland flow produced by the record-breaking heavy rain that fell.
North
This water then flows down towards Workington, causing flooding there.
4. At the confluence of the R. Derwent and R. Cocker, their discharges combine.
NorthWorkington
Cockermouth
Cumbrian Hills
R. DerwentR. Cocker
Keswick
2. Human Causes
1. Urbanisation – the towns such as Cockermouth and Keswick have increased the amount of impermeable surfaces which means that the
water gets to the river more quickly, increasing discharge.
Notice how the water flows over the surface of the road. Similar effects occurred in urban areas as the water could not infiltrate into the tarmac.
Notice how the water flows over the surface of the road. Similar effects occurred in urban areas as the water could not infiltrate into the tarmac.
2. Blocked sewers – inadequate sewer capacity and blockages caused sewers to back up and caused
flooding incidents, for example in Elliot Park, Keswick.
