5.5 Floods Flashcards
How does the jet stream cause flooding?
The jet stream is a ribbon of very strong winds that moves weather systems around the globe. Temperature difference between the cold Antarctic air and warm Caribbean air in conjunction with the earths rotation create the jet stream. The jet stream can drag cold or warm air creating high or low pressure.
How does ice melt cause flooding?
In cold regions large portions of rivers or lakes freeze completely during the winter causing river output to be very low. Diego the quick transition between winter and summer in these regions rapidly this ice melts increasing the discharge of water quickly. The water coming down the mountain can also not permeate into the soil yet as it is still frozen causing mass flooding. River Ob.
How does Indian monsoon occur and cause flooding.
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What were the primary physical causes of flooding in cumbria?
The jet stream- the jet stream in conjunction with low pressure systems brought prolonged periods of low pressure through the Lake District. Caused by two band of high pressure which forced the cold pressure through creating an atmospheric river.
Orographic rainfall- due to the topography of the lake the district and its vicinity to the west coast the main type of rainfall that forms here is orographic. It’s very common.
Antecedent conditions- the area is very wet a lot of the year round causing rivers to consistently be swollen and ground to be saturated
What secondary physical conditions caused the Cumbrian floods?
Rock type and topography- The region is mountainous causing water to rapidly enter rivers. Lots of impermeable rock impedes infiltration and caused more surface runoff.
Antecedent conditions- the rivers were already swollen
Drainage basin- cocker mouth is built in a drainage basin and at the confluence of two rivers increasing the chance of flooding.
How did population growth and urbanisation contribute to the Cumbrian floods?
Population growth and urbanisation- more people, more housing, more concrete, more tarmac, more roads means less possibility for infiltration and higher rates of surface runoff and interception.
How did poor river management cause the Cumbrian floods?
Channelisation- does not allow the rivers to meander causing the water to enter the river system quicker.
Bridges- bridges in the area are old and don’t allow water to flow through effectively.
Poor defences- the government didn’t invest enough thought into the river defences and they overflowed
How did economics and politics cause flooding in Cumbria?
Reservoirs overflowed due to companies trying to make profit and not releasing water into the river earlier into the season.
Farmers were asked to convert their land into wetland, no one agreed.
How has land use change caused flooding in Cumbria?
Deforestation- less infiltration
Natural grassland gone- less absorbent ground
Drainage from cropland- increased surface runoff
Sheep trampling causes the ground to become compact making it more impermeable, machinery on fields also causes compacting of the soil.
Sheep mean that no trees can grow
