Front | Back |
Hydrological Cycle Types
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Open System - Local
Closed - Global |
Water surplus can be described as having a
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- Budget
and a - Deficit |
Hydrograph |
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Types of river erosion
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- Hydraulic action - water turbulence and stuff
- Corrosion - Abrasion - Corrasion |
Types of Transportation
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Solution - Sediment dissolves in the water
Traction - Boulders Suspension - Gravels and pebbles Saltation - Particles bouncing |
Development of Meanders |
- Alternating Pools (Efficient) due to increasing erosive power at depth
- Alternating Riffles (Inefficient) due to friction - This causes turbulence leading to helicoidal, flowing twisting between banks causing erosion and deepening of outside bends and deposition on inside bend. - SINOUS |
South Asian Floods - 2007 Factors
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- Monsoon climate - 80% of all rain falls in four months
- 90% of Bangladesh's land is less than 10m above sea level - Melting ice and snow from Himalayas in summer increases Brahamputra's river discharge - Monsoon came early after a dry summer - Heavy rainfall - 170mm in 24 hours - Already saturated soil - Peak discharges of Ganges and Brahamputra coincided - Deforestation and over cultivation - Growth of urban areas - Collapse of old earth dams |
South Asian Floods - 2007 Impacts
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- 2000 died
- 100,000 got water-borne diseases - 25 million were made homeless - 45 schools destroyed, effected in total - $1 billion damages - Loss of raw materials - Loss of livestock (80% of pop rely on agriculture) - 550,000 hectares of land couldn't be planted rising world price of basmati rice by 10% - 10,000km of road destroyed |
Carlisle Floods - 2005 Factors
-RI of 200 years |
- Large, steep drainage basin with lots of streams (short lag time)
- Heavy rainfall for 36 hours, totalling 200mm (4 months worth) - Already saturated ground - High peak discharge of 150 cumecs (compared to 52) - Carlisle is built up - Drainage and sewerage overflowed |
Carlisle Floods - 2005 Impacts
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- 3 died
- 3000 were made homeless - Disrupted travel - 4 schools severely flooded - Stress related illness increase - £100 million damage - 35 businesses shut down - No electricity, telephone or transport services - Largest employer "United Biscuits" was flooded causing £5 million damage and 33 job losses - 70,000 addresses ahd no power - 80 buses destroyed with many roads and bridges |
Three Gorges Dam - 1994-2006
- Worlds largest hydroelectric power station - 26 turbines - Reservoir storing 22km3 |
- Seasonal flooding is common between June and August
- In 1954, 33,169 were killed from floods. 18 million had to evacuate and Wuhan was covered for 3 months |
Three Gorges Dam Positives
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- Major flooding has been reduced from once every 10 years to 100 years
- Likely to produce 22.5 gigawatts, 3% of Chinas demand - Reduction in flooding and easier river navigation - River Shipping is now possible as the reservoir is deeper than the old river path |
Three Gorges Dam Negatives
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- 1.3 - 2 million people have ahd to relocate, 13 cities and 1352 villages will be submerged
- Reservoir will also flood farmland, 657 factories and 1300 cultural and historic sites e.g Temple of Zhang Fei - Sediment deposition carried down the river will decrease causing risk of catastrophic flooding of dam - Habitat destruction for example Siberian crane and 100 baiji dolphins - Increase of flooding of tributaries leading to it |