Water Cycle Case Studies/ NecessaryFacts

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  • Created by: Alemae
  • Created on: 07-09-17 16:03

El Nino

El Nino

  • It appears every 2 to 7 years and brings droughts an floods
  • 6 months before its arrival is when El Nino can be predited (prediction not precise)
  • Both El Nino and La Nina have the ability to change the climate across more than 50% of the Earth
  • The La Nina that followed the 1997 El Nino lasted 33 months through 3 winters

Consequences (2015-2016 El Nino)

  • 9-24 months is the duration of an El Nino
  • 150,000  people in Latin America had to leave their homes due to flooding.
  • 180,000 people in Ethiopia had to eave their homes due to flooding
  • 8,000 domestic bovines in Zimbabwe died of hunger or thirt in the first drought months

1997 El Nino

  • Killed estimates 23,000
  • Caused as much as $45 billion in damage
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Sahel Region of Africa

Sahel Region of Africa (drought)

In the 1999-2000 Ethipian-Eritrean drought/famine crisis

  • 10 million people needed food assistance

Physical Factors

  • Drought sensitive as occupies a transitional cliate zone
  • Normal conditions - mean annual rainfall (85%) is nearly all concentrated in summer

Human factors which made it worse

  • Growing environmental degradation from overhgrazing of nomadic tribes
  • Deforestation for fuelwood
  • High levels of rural poverty
  • Rural population densities increased (pop had x2 every 20-30 years)
  • Population growth had outstripped food production in many areas
  • Any agriculture was rain-fed
  • Ethiopia and Eritrea were at war which bloked access to food for many
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California

California - What are the ecological impacts of drought?

  • Nearly 90% in severe drought (2016)
  • 4 year drought
  • 58 million severely dehydrated trees = fire hazard
  • 888 million trees experience water loss
  • 29 million trees already dead
  • El Nino hoped to bring rain
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Wetlands - S. Iraq

Wetlands - South Iraq

  • Marshlannd in S. Iraq almost destroyed due to dams on Tigris and Euphrate
  • Reduced flow
  • Saddam Hussein's drainage schemes worsened situation as tried to destroy lifestye of 250,000 Marsh Arabs who lived there
  • Overthrow of Saddam Hussein in 2003 - water flow. Extremely slow recovery of bad quality
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Monsoon Rain - Bangladesh

Monsoon Rain - Bangladesh

  • 80% of Bangladesh's annual rainfall = June to October
  • By end of monsoon season - almost 1/3 of country is underwater
  • Some parts of the Ganges basin receive 500 mm of rainfall in a day during a monsoon
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Tewkesbury Floods 2007

Tewkesbury Floods 2007

Effects

  • Nearly 50,000 homes affected
  • 13 people died and hundreds had to be evacuated
  • 9,000 businesses effected
  • More than 180,000 insurance claims
  • Flooding cost local councils £140 million
  • 50,000 properties without power for 48 hrs
  • 850 families had to stay in caravans, some up to Christmas 2008
  • Agriculture sector severly effected due to sewage water
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Causes of Tewksbury Flood in 2007

Causes of Tewksbury Flood in 2007

Physical Causes:

  • Geographical location - 2 big rivers (Severn and Avon) meeting in the town - confluence?
  • Summer of 2007 was wettest since records began in 1766
  • Little Sunshine - evaporation nope
  • Intense rainfall
  • Low pressure system located over Calais which moved N. West bringing warm air. Met cooler air of the North = instability ideal for storms
  • Soils ALREADY SATURATED = MORE FLOODING

Human Causes

  • Built on floodplains
  • No flood defences in Tewksbury
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Citrarum River, Indonesia - Sewage

Citrarum River, Indonesia - Sewage

  • Longest river in West Java
  • Source of water for 25 million people
  • Provides around 80% of surface water to Jakarta's water supply
  • irrigates farms that supply 5% of Indonesia's rice
  • Source of water for around 2,000 factories
  • Around 5 million people live in the River's basin
  • Poor sanitation and hygiene cause 50,000 deaths annually in Indonesia
  • Nearly 1/2 million residents drinking water with lead concentrations x25,000 recommended level
  • One of the world's most polluted rivers
  • 46 thousand hectares of critical land in upper course of the river
  • Used as toilet and garabage dump
  • Smell sometimes makes people fall unconscious in summer
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Chemical Fertilisers

Chemical Fertilisers

What do they do?

  • Fertiliers contain substances and chemicas like methane, CO2, ammonia and nitrogen = Global warming gases
  • Nitrous Oxide, byproduct of nitrogen - 3 most significant greenhouse gas
  • Nitrogen fertiliers break down into nitrates and travel easily through soil
  • It is water-soluable and can remain in groundwater for decade accumualting
  • Groundwater contamination linked to birth malformations and various cancers such as stomach cancer
  • Dead zones - if chemical fertiliser enters a body of water, it adds more nutrients to it
  • Algae rapidly grows as it is a plant blocking sunlight
  • Other plants at the bottom cant photosynthesis and produce oxygen
  • Dying algae feed microorganisms = even less oxygen
  • Trout and salmon die when dissolved oxygen too low = carp takeover
  • More than 400 of deadzones exist = 94,000 square miles of ocean
  • Deadzone in Gulf of Mexico is rougly the size of New Jersey
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Industry and Water

Industry and Water

Examples of pollutants:

  • Lead - non-biodegradable mterial and harful to health
  • Oils - don't dissolve and can stop photosynthesis
  • Nitrates - chemical fertilisers (eutrophication)

Causes:

  • Policies not enforced - CHINA - TNCs
  • Outdated technology = more polluting
  • Unplanned industrial growth - New Dheli - hyper-urbanisation?
  • Effects of Eutrophication
  • Thermal pollution  - Nuclear reactors leaving radiactive sludge in water = radioactive for DECADES - Japan 2011 Tsunami

Facts:

  • Industrial pollution biggest source of polllution in most of developed world
  • The Mississippi River dumps 1.5 million metric tonnes of nitrogen pollution inGuf of Mexico EVERY YEAR
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Over-abstraction of water

Over-abstraction of water

  • In many areas of Europe - groundwater is dominant source of freshwater
  • Take out too much = falling water tables
  • Saline intrusion widespread on Mediterranean coastlines of Italy, Spain and Turkey - Tourism
  • Malta - most groundwater can no longer be used for domestic consumption or irrigation due to the salt
  • Irrigation is the main cause of groundwater over-exploitation in agricultural areas

Examples:

  • E.g. Greek Argolid plain of Eastern Peloponnesus where it is common to find boreholes 400m deep contaminated by sea-water intrusion
  • E.g. Italy - overexploitation of the Po river in the region of the milan aquifer has led to a 25m decrease in groundwater levels over the last 80 years
  • E.g. Spain - more than half of the abstracted groundwater volume is obtained from areas facing overexploitation problems
  • Across England, a third of river catchments threatened by excessively high abstraction levels
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California Take 2

California Take 2

Climate:

  • Most of California is arid with annual percipitation at around 200-500mm
  • 2.65% of water lost through evapotranspiration
  • Only 22% for human use
  • Mountain snow provides 1/3 of california's water supply
  • By the end of the century, the Sierra snowpack is predicted to experience a 48-65% loss

River regimes in California:

  • Population = 40 million people so pressure on rivers is intense
  • Colorado River
  • More thwan 30 dams in the Sierra will get new operating licenses by 2020 that require river restoration and protection measures

Geology

  • San Andreas Fault - conservative plate boundary
  • Sierra Nevada mountains
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Future trends for the world

Future trends for the world

  • Hydrological cycle intensify = extremes more common (droughts and floods)
  • The moisture holding capacity of the atmosphere will increase by 7% for every degree of climate change
  • Are floods increasing, or simply just our vulnerability?
  • Over past 30 years, droughts more intense, widespread and consistent (Australia)
  • California's droughts
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Not enough water?

  • Not enough water?

Physical distribution

  • 60% of world's supplies contained in just 10 countries
  • 66% of world's populaton live in areas receiving only 25% of world's annual rainfall
  • Potential for conflict over trans-national boundaries
  • Problems with supply and demand

Gap between rising demand and diminshing supplies

  • 1950s - annual water withdrawal (km3) = 1,400
  • 2000 -  annual water withdrawal (km3)  = 4,000
  • Population 7 bn now but potential extra 3bn by 2030

Water availability gap:

  • Rich countries use up to x10 more water per head
  • By 2025 near 1/2 of the world's population iwll be water vulnerable
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