water cycle case studies Flashcards
(23 cards)
How Aswan dam disrupts water cycle
Disrupts the water cycle as it controls flooding downstream, lake Nasser behind the dam has significant evaporation losses
Deforestation in Amazon rainforest disrupting water cycle
Disrupts water cycle as when tree cover drops below a certain point, there is not enough transpiration, leading to not enough rain
Causes more draughts across the western world as humidity from rainforest moves to other countries
Yukon river, Alaska river regime
Rising river discharge in may due to snow melt, short summer ends in July
Water starts to refreeze leading to a gradual drop in the river level
From December to may water is frozen so there is very little river discharge
Amazon river, south america
River regime
Basin is so big that there is a four month delay between peak rainfall and peak discharge
River discharge increases gradually from jan-june as a result of heavy rainfall from dec-mar
River discharge then rapidly decreases until November when it starts to increase again
Indus river, india River regime
Snow melt in the Himalayas causes initial peak discharge in April, then 4 month monsoon season starts in June, rapidly decreases after this
Brazil 2014/15 drought
Water levels in rivers dropped so people began extracting groundwater illegally
25,000 licenses to drill wells were applied for, and this only accounts for 30% of wells dug, causing aquifers to drop to alarming levels
Australia 2019 drought
Partly caused by an extreme positive Indian ocean dipole event (difference in sea surface temperatures on either side of the Indian ocean which alters rainfall patterns)
Human causes: climate change will cause positive Indian ocean dipole events to occur three times more often, British colonisation - indigenous people used to manage the land by burning flammable shrubs
Cumbria 2015 floods
5200 homes flooded
major roads and railways disrupted for several days
6100 homes lost power
Physical: jet stream (band of fast moving air which moved north and south) remained over Cumbria for longer than normal, mismanagement of rivers
Pakistan 2022 floods
Scientists have said the major cause was climate change
Heatwaves caused temperatures to rise to over 49°c, causing glaciers to melt rapidly, also causing more intense rainfall as a warmer atmosphere can hold more water
Climate change affecting water cycles in the sahel region
Region is getting less drought creating the opportunity for regreening
Climate change affecting water cycle in california
Sierra Nevada region experienced three times the normal number of wildfires - intense mega droughts are also predicted causing significant problems with meeting future demand for water
Spain Ebro delta water tensions
Government created Ebro river basin management plan, which involves dams and irrigation
Environmentalists concerned over damage to ecosystem
Local people rely on the river for mussel farming
People further up river need water for irrigation for agriculture
Iraq water tensions
81% of Iraq’s water is controlled by neighbouring countries
Turkeys extensive dam and hydropower construction has reduced water flows into Iraq but turkey accuses Iraq of poor water management practices
Cancelada, spain water tensions
Public water supply was sold to a private company causing the price of water to increase
Locals were upset with decision as companies also don’t check water quality often enough
Local council could no longer afford infrastructure for water
Indus river, India and Pakistan tensions
Indus water treaty divided rivers into eastern and western
Indus river was given to Pakistan yet India started building dams upstream of river indus
India claims they are not breaking any rules as they are not diverting the water
Desalination israel
Israel now has a surplus of water through a national campaign to conserve and reuse water and through desalination plants
Started using drip irrigation for agriculture (water goes directly to plant roots)
Up to 80% of water for domestic use comes from desalination plants
Water transfer schemes china
North of china is very dry compared to south
Population increase and industrialisation make issue worse
South north water transfer project uses a series of dams, canals and pipes to transfer water
Singapore sustainable water management
Used to get 80% of water from Malaysia, but Singapore wanted to become more independent
Leakages were cut to 5%
Scaled water prices
Subsidies to protect poor citizens from water prices
Recycles water
Education schemes on sustainable water use
Integrated drainage basin management Colorado river
River basin covers 8 states
There is increasing demand for water due to reduced rainfall, so an agreement was made to divide up water
Agreement between US and Mexico gave Mexico right to store some Colorado river water in lake Mead, in return Mexico sells water to states in Colorado river basin
UNECE (Helsinki) water convention
Involved many European countries
Rules: prevent and control water pollution, ensure reasonable and impartial use of transboundary waters, ensure sustainable management
EU water framework directive
All EU countries involved
Rules: ensure EU rivers achieve good ecological status
Berlin rules 2004
States that every individual has the right to access secure and safe water, even in times of war, nations should manage water supplies without causing environmental harm
GERD dam water conflict
Dam built in Ethiopia, on Nile river
Ethiopia needs water for hydropower and agriculture
Egypt concerned that the dam will reduce it’s water security
Sudan has similar concerns but has closer relations with Ethiopia so wants to maintain regional ties
