Hydrological cycle breakdown

  • Created by: Alemae
  • Created on: 25-05-18 19:03

River Regimes

River regime = the annual variation's in a rivers discharge


  • Climate and seasons - can affect precipitation going into river (e.g. Colorado River with Sierra Nevada Mountains or The Mekong and the Himalayas - snow melt) and evapotranspiration
  • Geology and soil type  - permeable rock/soils as stored as groundwater - released into river as base flow
  • Vegetation cover - wetlands can hold water and release slowly


  • What is a river regime?
  • Identify 3 physical factors impacting it
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Drainage Basins

Drainage Basin = area of land drained by river and tributaries

Physical factors on Drainage basins

  • Climate - influences precipitation type and amount and vegetation
  • Soils/geology = impacts throughflow through infiltration - aquifer impact
  • Vegetation = evapotranspiration/infiltration/interception
  • Relief - affects run-off (gradient)

Human factors on Drainage basins

  • Deforestation - less evaporation = surface run-off increase
  • Urbanisation - less infiltration
  • Dams, etc. - increased evaporationpotentail
  • Abstraction - groundwater stores/aquifers


  • Define drainage basin
  • Identify physical factors impacting drainage basin
  • Identify human factors impacting drainage basin
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Storm Hydrographs

Storm Hydrograph - shows variation of river's discharge over a short period of time

Physical influences on river discharge

  • size of basin =takes less time for water to reach gauging stations
  • drainage density = more streams/rivers per unit = water moves quickly
  • relief = more surface run-ooff
  • vegetation = low density of vegetation = less infiltration = more surface run off
  • Saturation

Human influences on river discharge

  • Deforestation = less infiltration
  • Afforestation
  • Urbanisation = impermeable rock


  • Define what a storm hydrograph is
  • Identify 3 physical influences on river discharge and lag time
  • Identify 3 human influences on river discharge and lag time
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The Water budget

Water budget = precipitation - (evaporation + transpiration)

Water budget is the amount of water available for human use


  • Climate - increased temperature increases rate of evapotranspiration so less water. Affects type of preciptation (snow, etc.) and well as length/duration. (monsoon) Drought can also kill vegetation = less infiltration


  • What is the water budget?
  • How does the climate affect it?
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The Hydrological Cycle (A.K.A Water Cycle)

Key Points

·         IT IS A CLOSED SYSTEM (meaning no external factors can influence it)

·         It is driven due to solar power (sun) and gravity

Inputs in the water cycle

·         Precipitation - type (rain,snow) and dependent on seasons. Type of rainfall (orographic, frontal, convectional)

Fluxes in Water cycle (when water is moving)

·         Interception - absorbtion of water by lfat surfaces (leaves)

·         Infiltration - absorbed into soil

·         Throughflow - water heading down slope through soil

·         Groundwater flow - movement of water underground

·         Surface run-off - water at the top

·         Precolation - absorbed into rock from soil

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The Hydrological Cycle (A.K.A Water Cycle) PT. 2

Hydrological cycle - the movement and storage of water through the Earth


  • Evaporation - water heats up and becomes water vapour
  • Transpiration -  water absorbed by plants evaporates
  • Channel Flow - downhill movement of water in rivers


  • What is the "Hydrological cycle"?
  • Identify an input in the hydrological cycle
  • Identify 3  flows within the hydrological cycle
  • Identify 3 outputs in the hydrological cycle
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Types of rainfall

Convectional rainfall:

Common in tropical areas and U.K. in summer = thunderstorms. Land is hot, air above becomes hot = rises but then becomes cool = rain

Cyclonic rainfall:

When warm air is forced to rise over cold air as it is undercut = condensation, clouds, rain

Orographic rainfall

Hill/Mountains are a barrrier to warm air. Forced to rise = cooling and rain 


  • How many types of rainfall is there?
  • What happens in orographic rainfall?
  • What happens in convectional rainfall?
  • What happens in cyclonic rainfall?
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Water Stores

Water Stores:

  • Oceans - 97% of all water         (residence = 3600 years)
  • Cryosphere - 1.9%
  • Groundwater - 1.1%
  • Rivers,Lakes
  • Atmosphere - smallest amount of all stores               (residence = 10 days)
  • Soil Moisture

Notes - fossil aquifers are non-replenishable = not sustainable

Only 2% of all water in world is freshwater and of that, only 1% is surface water (87% is in ice and 12% groundwater)


  • How much water in the world is freshwater?
  • How much of that is in ice and ground twaer?
  • How much is surface water?
  • How much water globally does the oceans contain?
  • For how long does it stay in the ocean?
  • How much water in the cyrosphere?
  • How much water in groundwater?
  • How big is th atmosphere as a store? How long does water stay there?
  • Name two other stores of water?
  • What is the problem with fossil aquifers?
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The causes of drought

Tpes of drought/why

  • Meteorological drought - less precipitation either short-term or trends like climate change (Sahel - Africa)
  • Agricultural Drought - due to over-grazing, irrigation = desertification
  • Hydrological Drought - reduced stream flow and groundwater levels due to less rain(U.K. 1973 - minister for drought appointed)
  • Famine Drought- food shortage crisis = social, economic, environmental impact (Horn of Africa 2012-2014)


  • ENSOHas the power to change climate across more than half of the Earth – most powerful earth phenomena – disrupts weather patterns globally ( 50 days late – rainy season in South Africa)


  • Define the different type of droughts
  • How can humans affect drought?
  • What is the impact of ENSO?
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Australia - "Big Dry"

  • 30% of Australia usually affected by drought in any year

Big Dry 2006

  • Nationwide - 1 in a 1000 year event
  • Affected everywhere, particuarly Murray-Darling Basin = 50% of Australia's national agriculture output.
  • Needed for irrigated farming
  • Reservoirs fell to 40% of original capacity
  • Per capita water consumption = one of highest in world
  • Associated with climate change

El Nino

  • Southern Queensland 2002-3 (East Coast)


  • How bad in Austrlia affected by drought?
  • How did it impact the Murray-Darling Bain?
  • What happened to reservoirs?
  • Water consumption per capita?
  • What was the Big Dry associated with?
  • When has El Nino caused drought in Australia?
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Sahel Drought

  • Human factors = act like a positive feedback loop enhancing impact

Physical factors

  • 85% of annual rainfall concentrated in summer
  • Semi-arid


  • 1999-2000 Ethiopean-Eritrean Drought = 10 million people needed food assistance
  • Overgrazing by cattle
  • Population doubling every 20-30 years
  • Agriculture rain-fed
  • The two countries at war with each other = blocked food access


  • What hysical factors made the drought worse?
  • When was the drought?
  • How many people needed fos assistance?
  • How did agricultre and cattle worsen the situation?
  • What about population?
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Ecological impact of droughts

Why they are useful to Earth

  • Wetlands - cover 10% of Earth's surface
  • Act as temporary water stores - recharges water aquifers and stops eroision
  • Helps to maintain water quality by trapping and recycling nutrients
  • Carbon store

Destrution via drought and humans

  • Less interception = vegetation deterioration due to drought
  • Wildfires (California 2017 - 5,000 acres burnt in total)
  • Development - Europe and USA = 2.5 million square kilomeres been dstroyed
  • Exploiting fuel resources like peat = wetland habitat loss
  • Jonglei Canal Project = White Nile from Sudd Swamp to Suth Sudan dry areas
  • Dams on the Tigris and Euphrates = S. Iraq marshlands almost completely destroyed


  • Why are carbon stores important?
  • Identify physical factors leading to wetland destrution
  • Identify human factors leading to wetland destruction
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UK Cockermouth 2009 flooding (flash flood)

  • P C Bill Barker died
  • 314 mm of rain in 24hrs
  • Confluence - Derwent and Cocker
  • £28,000 per house in damages

Bangladesh (snow met and monsoon)

  • 80% of Bangladesh's rainfall - june to october
  • End = 1/3 of country underwater
  • Himalayas - feeds Mekong etc.

Causes of flooding

Human = deforestation, urbanisation, building on floodplains, straightening rivers, dams

Physical = saturation, prolongued rain, flash flood, drought = flooding


  • How does mnsoon season affect Balngladesh?
  • How can flash floods have an impact?
  • Human causes of flooding?
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Tewksbury Floods 2007

Social impacts

  • 13 people dead and hundreds evacuated
  • 50,000 homes without power for 48 hours

Economic impacts

  • 9,000 businesses affected
  • Total cost to U.K. economy = £3.2 billion

Environmental impacts

  • Sewage polluted agricultural crops
  • Destroyed some habitats


  • Building on floodplains - Avon and Severn
  • Soil saturated already
  • Summer of 2007 in UK wettest since reords began = low pressure system
  • No flood defences
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Climate change impact on The Hydrological cycle

How will climate change affect the water cycle?

  • More CO2 and greenhouse emissions = enhanced greenhouse effect = more land heat
  • Affects ENSO, evapotranspiration and temperatures globally
  • Drought
  • More water in Atmosphere
  • More storms?


  • A 1 degree rise in temperatures could increase global run-off by 40%
  • In the past 30 years, droughts have  become more widesread and persistent


  • Identify 3 ways in which climate change may affect the Hydrological Cycle
  • Give a piece of eidence to support your claim
  • Why is it difficult to say definitively how climate change will impact the water cycle?
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Water Security

Key Terms

  • Virtual Water - hidden flow of water in commodities and trade
  • Water Stress - annual supply of water per person BELOW 1700m3
  • Water scarcity - annual supply of water per person BELOW 1000m3
  • Economic Scarcity - fresh water sources limited because of lack of money, governance or tech
  • Physical Scaricty - when more than 75% of regions blue water flows being used. (25% of world)

Why not enough water?

  • 60% of world's water supplies in just 10 countries
  • 66% of world population lives in places with 25% of world's annual rainfall
  • Rising middle class (emerging countries = more consumption  - toilet =8 litres) Rich countries use up to 10x as much water per head
  • Population growth - 8 billion by 2030 (food = irrigation)
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Physical and human factors affecting water scarcit

Physical factors

  • Geology = controls distribution of aquifers (water bearing rocks) = groundwater storage. Permeable rock absorbs - can't be evaporated - all year supply
  • Climate = global distribution oof water, seasons, monsoons, ENSO, climate change
  • River regimes = Amazon River has annual discharge of 175,000 cubic metres per second. Droughts in 2005 and 2010 covered twice the size of California in S. America. Deforestation.
  • Distance from sea
  • Relief of land

Human factors

  • Pollution - trans-national rivers. 1 billion people globally without safe water. 1/3 of all rivers in China highly polluted. 2 milllion cihnese people suffer from water related illnesses. (Cancer-cluster villages - liver and digestive cancers)
  • Ground water contamination - Nearly 20% of all wells in Bangladesh unsafe due to high concentrations of arsenic
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More human causes of water scarcity

Industry Pollution

  • Fukishima Nuclear Meltdown 2010 = radioactive sludge at bottom of water bodies
  • Biggest source of pollution in most of developed world (TNCs, over-population...)

Sewage (Black Water)

  • Citarum River indonesia - used as toilet - 400 tonnes of waste of livestock every day. World's most polluted river. Summer = unconscious. 5 million people rely on river supply. Lead concentration = 25,000 times recommended level. 

Chemical fertilisers

  • Deadzones = more than 400 exist = Gulf of Mexico size of New Jersey (hypoxia)
  • Green revolution - has chemicals like nitrogen, methane... (carbon)


  • Salt encroachment = Italy, Spain, Turkey = falling water tables
  • Rivers less reliable - not continual flow
  • Agriculture and Industry biggest users of water (70% and 60% respectively)
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Economic scarcity - Bolivia Privitisation

What was it?

  • Structural Adjustment Program by IMF (privitisation a requirement to recieve aid)

What happened?

  • TNC Aguas Del Tunari in Charge. Their annual revenue = $14 billin in 2000 v.s. Bolivia's national budget of $2.7 billion. Forced out due to protests.


  • Bolivia has socialist leanings - water is seen as right not commodity
  • Oversight of capitalist organisation - not always right way
  • One of the poorest countries in S. America


  • How can privitisation cause water scarcity?
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The Aral Sea - water and development (causing scar

What happened?

  • Was once world's 4th largest inland sea
  • 2007 - 10% of original size


  • USSR tried to irrigate to create jobs in unproductive region
  • The fishing community once employed 60,000 people. Industry collapsed
  • Health issues - weapons testing, pollution - 10% of children die in first year.
  • 160/310 bird species left
  • Up to 10 million may be foorced to migrate and become environmental refugees


  • What has physicaly happened to the Aral Sea? How has it created water scarcity?
  • What has been the economic impact?
  • Social impact?
  • Environmental impact?
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Israel and Paltestine (International water conflic


  • Israel exploits more than 80% of Palestine's water
  • Israel consumers = 370 m3 a year per person
  • Palestine consumes = 107 m3 a year per person

West Bank 

  • Palestine people banned from making wells and Israelians move in
  • Local Arabs there = 82 m3 year per person (1.4 million of them) 
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The Mekong (international conflicts)

Backgroung Information

  • 15 large dams already in place in Upper -mekong = China geo-political leverage
  • Water - threat of war (social control over South-East Asia)


  • Cambodia - by 2050 its population is expected to jump from 15 million to 24 million
  • Could hinder crop irrigration, fishing and endanger food security
  • Exacebates drought conditions
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Coca-Cola in India

What happened?

  • For every 3.75 litres of water used by the plant, it produced one litre of product and a large amount of waste water.
  • Plachimada now gets its drinking water through pipes, that provide water for only a few hours once in two days, and through tanker lorries which also arrive once in two days.
  • Coca Cola subject to criticism that they are depleting groundwater aquifers in the State of Kerala.


  • How does this show internal conflicts within a country?
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Water insecurity response - Dams

Three Gorges Dam

  • World's largest HEP
  • Cost $24 billion
  • 1.3 million people relocated
  • Caused landlides and increased erosion


  • Give an example of a dam
  • How much did it cost?
  • Where there any social impacts?
  • How did it affect the area environmentally?
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Desalinisation - response to water insecurity


  • The "M" station in Jebel Ali
  • Cost $2.7 billion
  • can produce 140 MIG of desalinised water every day
  • Water is free in Dubai
  • Leads to overuse as some shopping centres have aquariums and ice rinks


  • Where has desaliniation taken place?
  • Give a specific plant name
  • How much can it produce?
  • How much does water cost in Dubai?
  • What has this led to?
  • Is it sustainable?
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Water Transfers - Response to water insecurity

Kielder Water

  • Cost £167 million to build reservior
  • 58 families moves
  • The dam and reservoir is in the cheviots hills. Controls water going down the Tyne, Wear and tees and distributes to Newcastle, Sunderland and Middlesborough through pipes
  • Generates 6MW - enough for 4,000 homes per year


  • Give an example of a UK Water transfer scheme
  • How much did it cost?
  • How many families were moved?
  • How does it work?
  • How much does it generate in electricity?
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Integrated Water Resource Management -

What is IWRM?

  • IWRM is a broad framework in which decision makers can collaboratively decide the goals of water management and co-ordinate how to achieve them.

Example: - Lerma-Chapala River Basin (Mexico)

  • One of world’s most water-stressed basins.
  • From 1981 to 2001, Lake Chapala lost 90% of its natural volume and the remaining water was left heavily contaminated
  • Now, water quality is improving with around 60 per cent of discharges eliminated
  • Finance has been secured to invest in water sanitation and treatment programs.
  • Natural capacity of lake restored
  • 1970s = move towards IWRM
  • after 30 years, the benefits are starting to be realised.


  • Give an example where IWRM has been successful
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