4b.5 - River Severn Case Study Flashcards
What were the July 2017 antecedent conditions?
Very high rainfall - 140mm
highest in 100 years
Why is the River Severn discharge high anyway?
Many tributaries join the River, e.g. Avon
What’s the river velocity in the lower course?
High
What’s the impact of river velocity in the lower course?
Meander erosion, affecting towns on the necks of river meanders
What are the highlands like?
Cambrian / Welsh mountains - steep, resistant shale rock
What are the main towns vulnerable to flooding?
Shrewsbury / Tewkesbury
Why are the main towns vulnerable to flooding?
They’re located in river meanders - bridge points sites
How much damage did the local council have to pay for?
£140,000
How much money has insurance had to cover for housing?
48,000 houses
£20-30,000 for each house
What’s been the overall financial cost of flooding along the Thames?
£3.2 billion
Why is there increased ‘hydrological’ risk from flooding along the Thames?
Continuous Atlantic depressions (low pressure) / storms crossing the UK
Why is there increased ‘social’ risk from flooding along the Severn?
Increased population, building on flood plains
Why is there increased ‘economic’ and ‘hydrological’ risk of flooding along the Severn?
More urban areas -
More impermeable surfaces
More surface runoff
Why is there increased ‘ecological’ risk of flooding along the Severn?
More deforestation
Less interception
More surface runoff
More flooding
