Physical Landscapes: Rivers Flashcards
How does the river valley change as the river moves from the upper course to the lower course?
valley becomes wider and deeper
How does relief contribute to flooding?
steep slopes allow for water to run over the land quickly - less time for water to seep into the soil, more water entering river channel
How does precipitation contribute to flooding?
torrential rainstorms can lead to flash flooding
How does rock type contribute to flooding?
impermeable rocks does not allow infiltration of water (e.g. clay) - more water flowing to river
How does urbanisation contribute to flooding?
impermeable rock (tarmac) means water drains into river channel
What is lag time?
number of hours between peak rainfall and peak discharge
What is meant by the term ‘hard engineering’?
use of man-made structures to control the flow of a river and prevent flooding or erosion
What is meant by the term ‘soft engineering’?
managing a river using natural materials and mimicking natural processes to protect more vulnerable areas
4 hard engineering strategies
-channel straightening
-embankments
-dams + reservoirs
-flood relief channel
4 soft engineering strategies
-flood plain zoning
-flood warnings + preparation
-afforestation
-river restoration
How does flood plain zoning reduce flood risk?
-low quality land on flood plains
-e.g. sport pitches, car parks, livestock farming
How does afforestation reduce flood risk?
-intercepts water
-slows down water in drainage basin
Where does the Jubilee River flood-relief channel flow?
flows from West to East, through Greater London
What 2 areas does the Jubilee River flood-relief channel flow through?
-Windsor
-Wraysbury
How much did the relief channel cost?
£110million (most expensive flood-relief scheme in UK)
