Water On The Land: Case Studies Flashcards
BOSCASTLE: when?
16th August 2004
BOSCASTLE: weather?
- Remnants of hurricane Alex
- High pressure cold air from North
- Low pressure hot air from South
BOSCASTLE: antecedent conditions
Hot summer so baked ground (saturation was quick). This meant an increased surface runoff and a reduced lag time.
BOSCASTLE: How much water?
Over 60mm in 2 hours. In total, 310million Gallons. All frontal rainfall
BOSCASTLE: topography
- High drainage density (small drainage basin with 3 tributaries).
- Lack of vegetation and impermeable rock underneath
- Steep valley
- High tide meant water backed up in the harbour
BOSCASTLE: physical effects
58 properties flooded 4 foot bridges destroyed 1000 lives effected 100 cars washed away Sewage pipes burst creating unsanitary conditions
BOSCASTLE: rescue effort
The flash flood forced people onto their rooftops, over 120 people were winched to safety (biggest peacetime air evacuation). Only 1 broken thumb
BOSCASTLE: economy?
£2million of damage, HOWEVER!!! tourism increased. A new scuba diving business to see the cars in the harbour
BOSCASTLE: response?
As it was a 1 in 400 year event and there was no loss of life, no drastic action has occurred.
A new 400m culvert has been built to divert a tributary and protect the Wellington Hotel.
PAKISTAN: when?
July-September 2010
PAKISTAN: which river?
River Indus
PAKISTAN: moist?
Wettest monsoon ever, the previous record was 313mm in one day
PAKISTAN: why was it moist?
An extremely hot summer meant a bigger pressure gradient that sucked in more water quickly. Also global warming has heated the Indian Ocean so that it carries more precipitation. There were also LA NINA conditions
PAKISTAN: what happened in the uplands?
In upland areas the moisture that had been sucked north began to condense due to RELIEF RAINFALL. This combined with icemelt from the Himalayas.
The steep valleys, dry ground and sediment build up all increased the DISCHARGE VELOCITY DOWNSTREAM
PAKISTAN: (as we go through) what else worsened the problem
- Deforestation and Farming = surface runoff
- A lack of preparation from the government
- Poor quality bridges and dams burst, releasing surges downstream
- Barrages and Urban Draining moved the problem elsewhere
PAKISTAN: effects (humanitarian)
- 20 million effected
- Death toll 1877
- Millions displaced
- 1/5 of Pakistan underwater
- Rich poor divide increased
- Schools closed
PAKISTAN: effects (economic)
5.3 million jobs lost Pakistan's GDP decreases by 2% Debt increases to $55 billion Acres of farm destroyed (cotton prices soar) and millions of livestock washed away 11000km of roads lost
PAKISTAN: aid
International aid from USA, UK, Norway ect
PAKISTAN: aid (problems)
Slow and disorganised, some areas were inaccessible. Flood defences not erected downstream. Remote settlements never reached. In refugee camps food was stolen and resold due to a chaotic ID card system.
PAKISTAN: future?
Country set back
Flood defences
Warning systems
Preventive measures
KIELDER WATER: unnecessary?
The NW of England has never had water shortages, it has never been less than 90% full.
KIELDER WATER: pros
Reservoir feeds homes and industry up to 80miles away AND generates HEP for the national grid (20,000 MWh per year = 8,600 tonnes of carbon dioxide saved per year). It is a flood defence which also has cycle paths and a ferry
KIELDER WATER: economics
7years to build and cost £167 million, it sells water and electricity to the rest of the country and has created jobs in tourism.
KIELDER WATER: the environment
Flooded an “area of outstanding natural beauty” . 1.5million trees cut down.
However the largest man made forest in Europe now, the new lake is a new ecosystem and the area is still a national park
