Water Cycle And Water Security - Case Studies Flashcards
(32 cards)
Malham cove - storm Desmond 2015
- Limestone country = permeable rock
- 350mm rainfall in a day
- Limestone became saturated and thus impermeable
Drought in the Sahel region
– How have Humans Contributed –
- overgrazing by tribes and deforestation
- Failure to distribute food due to political instability
- Locust infestation not controlled
– Physical causes –
- - Occupy’s transitional climate zone = drought sensitive
- Rainfall dependent on the ITCZ
- Rainfall belts have shifted
– Facts –
- grain production down 36%
- 18 million facing food crisis
Drought in Australia
– Human causes –
- River Murray has been over extracted for water - no water flows at it’s mouth anymore
- Affluent pop = more water consumption
- Farmers have too many licenses to abstract water from the river Murray
– Physical factors –
- Related to El Nino
- Climate change reduced rainfall by 15%
– Facts –
- ‘Big dry of 2006’ - 1 in 1000 year event - reservoirs ell to 40% capacity
Drought in the Horn of Africa
– Human causes –
- Pop doubled in last 30 years
- World food programme reduced rations
- Funds go towards the conflict instead of food
– Physical causes –
- Strong La Nina event
- Climate change = more erratic events
– Facts –
- 10% of pop faced starvation
- effects million people
Boscastle floods
- 2004
– Physical causes – - Small, round drainage basin
- Surrounded by steep slopes
- 3 rivers flow through the area
- Ground was saturated
– Human Causes – - Street patterns and man made structures made flooding worse
- Cars blocked bridges leading to a greater build up of water
Effects of the Boscastle floods
– Environmental –
- 50 cars washed into the harbour and coastline littered in rubbish
– Socio-Economic –
- Shops shut which stopped tourism
- £250,000 in damages to small scale infrastructure
Response to the Boscastle floods
- 120 winched to safety
- Largest joint Royal navy and RAF rescue since 1979
Storm Desmond -2015 - Causes
– Physical causes –
- Atlantic low pressure system = prolonged heavy rainfall
- already saturated ground
- Jet stream remained over NW for long time
– Human Causes that exacerbated flood risk –
- Changing land use - sheep overgrazing which reduced interception
- Mismanaging of rivers
Effects of Storm Desmond -2015
– Environmental effects –
- Rivers filled with debris and sewage
- Saturated ground = more decomposition - releases gasses such as Hydrogen Sulphide
– Socio - Economic effects –
- 3000 homes flooded
- £500mn in damages
- Insurance claims = £6 billion
Response for Storm Desmond -2015
- Environment agency wanted soft engineering:
- Reforestation
- Restoration of floodplains
- Refusal of planning permission near rivers
Californian Drought - 2015 - Causes
– Physical –
- Low rainfall (22 inches annually )
- Hottest year in states history
- Snow in Nevada mountains at all time low
– Human –
- Uses more water than any other state
- Pop increasing to 47mn by 2040
Actions taken against Californian Drought - 2015
- Restrictions on water use and public effort to preserve supplies
- Watering grass was banned
- Water fountains etc turned off
Impacts of the Californian Drought - 2015 on biodiversity
- Decline in wild flower density - Could lead to local extinctions
- Grasslands provided less nutrients
- 2500 forest fires in 2015 in the state
Water security issue in Murcia (Spain) - Causes
– Physical causes –
- Global warming
- Only receives half of water needed from natural sources
– Human causes –
- Pop growth
- Demand from tourists
- New airport and golf courses for tourists - water intensive
Water security issue in Murcia (Spain) - Impacts
- Relies heavily on agriculture - main crops are olives and tomatoes = badly affected
- rise in temps by 2 degrees leads to a 10.7% reduction in rainfall
Water security issue in Murcia (Spain) - Solutions
- Smart irrigation - Drip-feed irrigation systems = increased agricultural productivity
- Regeneration of wastewater = makes up 10% of the regions annual water budget - resulted in Segura river becoming one of cleanest in Spain
Effects of climate change on the Hydrological cycle - the Good - Sahel region in Africa
- Located in north Africa across Chad Senegal and Ethiopia
- amount of rainfall = 100 - 600mm annually - 90% between July - Sept
- Tough years = 1970-1995 = all below average rainfall - led to famine
- Rainfall is now coming closer to the average
Effects of climate change on the Hydrological cycle - the Bad - California
- 2018 wildfire season = The state is the 2nd most forested - lack of rainfall killed trees which burn easily - drought reduced water that could be used on the fires
- 25% of pop lie in high risk areas
- Climate change is to blame as the trees that were killed reduced moisture in the area which caused the fires
Conflict on the Nile
- Climate is variable in the area = wet seasons are arriving later and heavy rain washes billions f tonnes of sediment into the river
- Grand Ethiopian renaissance dam = increased geopolitical tensions as Egypt relies on Nile for 95% of Water
California’s growing water issue
- Most water comes from surface water supplies in the North - most farms and people are in the South
- Pop = 10mn
- LA’s imported water comes from Colorado river and North California via the Los Angeles Aqueduct
- However growing pop and less snow is leading to water insecurity
Los Angeles urban water cycle
- Capture, storing and reusing of water already in the city
- LA is using permeable pavements and encouraging rain barrels in gardens etc
Los Angeles Central Valley Project
Construction of dam to stop intrusion of salt water into the Bay Delta region - completed in 1944 - produces 100,000 Kw of electricity - today consists of 20 dams and reservoirs
The Aral Sea
- During Soviet union canals were built to irrigate cotton and rice farms - less water went to the sea
- Volume fell by 80% from 1960-1998
- 2007 = 10% of original size
- 2009 = high rates of salinity make it hard for fish to survive
Impacts of the shrinking of the Aral sea
– Environmental –
- Exposed sea bed has caused colder winters and hotter summers
- sea bed also contains fertilisers used in the farms which cause toxic dust storms
– Socio - economic –
- most of the 40,000 fishing jobs are gone
- High rates of raspatory diseases due to the toxic dust storms
