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Surpluses in the hydrological cycle (Cumbria as a flood risk area (Social,…
Surpluses in the hydrological cycle
Storm Desmond
Basic Facts
Cumbria, December 2015
Deep Atlantic low pressure system
Warm conveyor from the Caribbean brought heavy rains
341.1 mm of rain in one day
5200 homes flooded
Disruptions to rail and roads
6100 homes lost power due to the flooding of a substation
Causes
Orographic rainfall caused by Cumbrian fells
Moist air mass stayed over Cumbria for 48 hours
Warm conveyor brought by a jet stream from the Caribbean
Too much rain for the saturated ground to absorb, leading to increased overland flow
Also caused by impermeable surfaces and clogged drains
Bangladesh
Basic Facts
Monsoon rainfall
70% of the average annual rainfall falls in around 100 days
80% of Bangladeshi people are exposed to flood risk
12.5 metres above sea level
Exacerbating flood risk
Farming
Overgrazing by sheep reduces evapotranspiration
Soils are dried out
Mismanagement
Cumbria
Before 2005, raised riverbanks and pumping systems were used as flood defences
Reinforced after 2005 floods
Schemes based on flood return period
Keswick flood wall was 5 metres high- but the 2015 flood was 6.9 metres
Designed for a 1 in 100 year flood
Cumbria as a flood risk area
Social
3000 homes were flooded in 2005, 5200 in 2015
Residents suffered psychological trauma
Businesses and public services shut down
Environmental
River banks eroded, adding to the future flood risk
Rivers were polluted with chemicals
Noxious gases such as hydrogen sulphide were emitted by animal corpses and dead plants
Economic
Total costs: £100 million in 2005, £400-500 million in 2015
Insurance claims nationwide exceeded £6 billion
Tourism dropped