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The water cycle and water insecurity (Lesson 1 - What are the components…
The water cycle and water insecurity
Lesson 1 - What are the components of the global water budget
Stores
- the are stocks of water , places where the water is held . E.G. oceans
Fluxes
- this is the measurements of the rate of flow between stores
Processes
- the physical factors which drive the fluxes of water between stores
The water system is closed, we have been drinking the same water as our ansestors
Closed system
- where inputs and outputs are balanced. A system has input and output linked to stores and flows
Solar energy
- energy from the sun, heating water and causing evaporation/transpiration
Gravitational potential energy
- ways in which accelerates under gravity, thus transporting it to river and eventually to the sea
The hydrological cycle
In the ice age more water was held within the cryosphere (the frozen water part of the earths system) in a solid form of snow or ice
The recent global warming has reversed this
Humans have build water storage reservoirs which increases their security of a water supply
On the land water is stored in rivers, streams, lakes and groundwater in liquid form this is known as blue water and is the visible part of the water cycle
Water is also known as green water, the invisible part of the water
Fossil water
- untapped ancient stores of freshwater exists in polar regions and beneath many deserts. Due to new technologies we can access this water known as aquifers
Kenya lotikipi aquifer contains contains an estimated 200 billion cubic metres of freshwater, this will only supply kenya for 70 years at their current rate of use
Water stores
- icecaps residence time (how long the water will remain in the store) is up to 15,000 years whereas atmospheric moisture is just 10 days
The importance of tropics
- sun allows for intense solar radiation causing evaporation. Trade winds push water vapour in near the tropics where they cool into clouds. Most of the worlds rainfall is created in the ITCZ
How the thermohaline circulation works
- 1) Ocean water in the polar regions is more saline and denser so sinks. 2) cold sinking water draws in warmer water from the surface which in turn draws water from the tropics. 3) The movement of the water from the tropics draws cold water up from the bottom to be warmed again
Global extremes
- Solar energy is concentrated in the tropics. Evaporation form the sea produces high rainfall.
Polar hydrology
- There are freeze/thaw seasonal changes. Limited vegetation cover reduces the heat absorption
Tropical rainforest hydrology
- Few seasonal changes. Dense vegetation which intercepts and consumer up to 75% of precipitation
EQ1
Lesson 2 - What are the components of a drainage basin
The Bradshaw model
Downstream
(these factors are at their most here): channel depth, occupied channel width, mean velocity, discharge, volume of load
Upstream
(these factors are at their most here) - Load particle size, channel bed roughness, gradient
The drainage basin cycle
: is a open subsystem within the global hydrological cycle, often referred to as the catchment, the boundary is defined by the watershed, they can be any size from a small stream to a major river across international borders
Basin wide factors, physical factors within the drainage basin system and effects in inputs, flows and outputs
Climate
- influences the type and amount of precipitation overall and the amount of evaporation, also has an impact of the vegetation type
Soils
- this determines the amount of infiltration and through flow and indirectly, the type of vegetation
Geology
- can impact on subsurface processes such percolation and groundwater flow, and indirectly alters soil formation
Relief
- Attitude can impact on precipitation totals, slopes can affect the amount of runoff
Vegetation
- The presence or of vegetation has a major impact on the amount of interceptions, infiltration, and occurrence of overland flow as well as transpiration rate
Human impacts on the drainage basin
- urban surfaces are impermeable and increases the rapid surface runoff, evaporating and intercepting
Physical factors affecting the drainage basin
Precipitation
- Any form of water falling from the sky. This is linked to the cline and weather systems around, for instance the highest inputs are in the tropics. High levels of solar radiation causes rapid convection of warm air. Land relief also has an effect on the rainfall levels
Interception
- water is prevented form reaching the ground due to vegetation. Water may drip down through stem flow or through flow. The lighter the rain and more vegetation there is the more interception there will be
Percolation and groundwater flow
- Water at bedrock moves slowly through percolation. The water fills spaces know as groundwater flow. the rate of these things depends on the permeability of rock
Direct runoff
- Saturated overland flow happens when water accumulates in the soil until the water table reaches the surface to run off the surface, may reach river channels and cause flooding
Infiltration and through flow
- vertical downward movement of water in soil, this depends on how much water there is in the soil and the rock and soil type. Moves under the influence of gravity towards a stream or river
Evaporation and transpiration
- Evapotranspiration is the amount of moisture removed from a drainage basin by evaporation and transpiration, higher temperature means faster rate
Channel flow
-This is water that has collected or flow in a river. the discharge of a river is the volume passing a specific gauging station at a time, discharge is dependent on precipitation
Rainfall
Orographic rainfall
- as it rises it cools over high ground producing heavy rain
Convectional rain
- the rainfall is usually intense and associated with electrical storms and thunder
Frontall rainfall
- Fronts are formed as part of a low pressure area , when warmer moist air meets colder polar air. The warmer air is forced to rise over the cooler dense air, forming rain along with warmer and cooler fronts
Human disruption to the DBC
( drainage basin cycle): farming and irrigation, deforestation, urbanisation
Ground water abstraction
- In some places water is taken by aquifers at a rate higher than replenishment levels
China
- They are using groundwater for farming in order to feed their growing population, but with their climate the same the water is not being replenished at the same rate they use it, as a result it has dropped by a meter from 1974-2000
Dam construction
- Building dams increases the surface water stores and evaporation
Egypt
-Lake Nasser behind the aswan dam in Egypt is estimated to evaporate 10-16 billion cubic metres every year, this is a 20-30% loss Egyptian water volume from the river nile
Urbanisation
Building creates impermeable surfaces reducing infiltration and increasing surface runoff and throughflow through artificial drains. Often increases river discharge
Where - increased risk across the UK, such as increased flooding in York (2015) and Manchester (2015) and Maidenhead (2014)
Cloud seeding
- Attempt to change the amount of type of precipitation
How it works
: 1) Silver iodine is released by plane or ground based generator. 2) Silver iodine particles reach the targeted clouds. 3) The silver iodine aids in the formation of ice crystals. 4) the ice crystal become large enough to fall and create snow
Key terms
Inputs
Precipitation
- Moisture in any form
Storage
Interception
- temporary storage, as water is captured by plants, buildings and hard surfaces before reaching soil
Vegetation storage
- any moisture taken up by vegetation and held within plants
surface storage
- any surface water in lakes, ponds and puddles
Soil moisture
- water held within soil
Groundwater storage
- water held within permeable rock
Channel storage
- water held in river and streams
Flows and processes
Infiltration
- water entering topsoil. Most common during slow or steady rainfall
Through flow
- Also known as interflow; water seeping laterally through soil below the surface but above the water table
Percolation
- The downward seepage of water through rock under gravity, especially on permeable rocks like sandstone and chalk
Stem flow
- water flowing down the plants system
Baseflow
- slow moving water that seeps into the river channel
Channel flow
- the volume of water contained within a river channel
Surface runoff
- Flow over the surface during an intense storm, or when the ground is frozen, saturated or an impermeable city, also called land overflow
Peak rainfall
- the highest amount of rainfall
Peak discharge
- The highest discharge (largest amount of water carried in a channel)
Lag time
- The time difference between the peak rainfall and peak discharge
Storm flow
- Resulting from increased precipitation involving both surface and throughflow
Rising limb
- Shows how the flow (discharge) of the river is rising
Falling limb
- Shows the flow (discharge) of the river decreasing
Outputs
Evaporation
- the conversion of water into vapour
Transpiration
- Water taken up by plants and transpired onto the leaf surface
Evapotranspiration
- the combined effect of evaporation and transpiration
River discharge
- the volume of water passing through a certain point in the channel over a certain amount of time
Lesson 2.5
Case study - Deforestation issues in Amazonia
Over 20% has been destroyed
the trees act as the green lungs removing CO2
the amazon contains 60% of the worlds rainforest
the amazon affects the water cycle, as more water runoff into he amazon drainage system exacerbates the chance to flooding and mudslides
In a forest environment 75% of intercepted water is removed by EVT to the environment which is reduced to 25% when the forest is cleared
el nino southern oscillation (ENSO) can lead to significant droughts causing forest fires
Overland flow also increases the amount of soil erosion and degradation as nutrients are washed away
Lesson 3 - How are water budgets and river regimes affected by the hydrological cycle
Hydrographs and river regimes
: a graph that shows the volume of water throughout the year (its discharge), the climate it is in in the main factor
Flood hydrograph:
This plots the river during one single storm event, shows hourly discharge
Water budgets:
This is the annual balance between inputs(precipitation) and outputs (the channel flow and evaporation),
Equation
: precipitation = channel discharge + evapotranspiration +or- change in storage
The water budget shows when after naturally enters and leaves
This is positive when there is enough water for people, more rainfall than evapotranspiration
This is negative when there is not enough water for people, when evapotranspiration is higher than rainfall
Water budget - soil
when precipitation is greater than evapotranspiration then the pores of the soil are refilled -
soil moisture recharge
when soil becomes saturated, excess water can't infiltrate -
soil moisture surplus
when evapotranspiration is greater than precipitation there is a reduction in water stored in the soil -
soil moisture utilisation
eventually all the soils water will be used up -
soil moisture deficit
River regimes
- this is the annual variation in discharge or flow of a river. These are the main factors:
drainage basin area
geology
mean annual percipitation
mean discharge
climate
time of year - seasons
Examples for river regimes
Amazon river
- in south america, humid climate, snowmelt from mountainous region, huge drainage basin
Yukon river
- North america, tundra climate, mountainous region, water freezes in winter and melts in summer, large drainage basin
River nile
- Northern africa, warm/arid climate, dam construction reduced water flow by 65%, seasonal flow
River indus
- pakistan and india, snowmelt fork himalayas, monsoon rainfall which is seasonal, medium sized basin
Lesson 4 - How can storm hydrographs help us understand rivers
A storm hydrograph
- is a graph that shows how a river changes as a result of rainfall, its shows rainfall and discharge
Factors that affect the shape of a hydrograph:
The size of the drainage basin
- the larger the basin the more water it can hold, reducing the chances of flooding)
Snowfall
- snow melt causes water to get to the channel faster
Geology and soil type
- impermeable and saturated surface will lead to surface runoff
Natural vegetation
- the more vegetation there is the higher the interception
Lesson 5 - Players in the hydrological cycle
Hydrological cycle
Within the UK planner state required to determine whether any proposed development will influence flood risk with a change in land use
Within England, the national planning policy framework (NPPF) sets out strict guidelines
The impact of urbanisation on the hydrological cycle
Building activity leads to clearing of vegetation, which exposes soil and increases overland flow
The high density of buildings means that rain falls off the roof and is swiftly dispatched into drains and guttering and piping
In extreme weather events, urban areas like Manchester, Leeds and York are highly vulnerable
Planner have to use land zoning techniques and have tighter restrictions due to surface runoff
Urbanisation changed the way the hydrological cycle works
The more vegetation there is the less evapotranspiration takes place
The more buildings there are the more runoff there will be
Less vegetation leads to less shallow and deep infiltration
more buildings mean more impermeable surfaces
SuDS
- recently sustainable drainage systems have been introduced to reduce runoff produced from rainfall. examples include:
Green roofs
- vegetation cover, planted over a waterproof membrane
Permeable pavements
- to delay runoff by using gaps between pavements
Filter drains
- trenches filled by gravel to intercept runoff by a motorway
Lesson 6 - What are the causes of droughts
Draught
- an extended period (a season, a year or several years) of deficit rainfall relative to the average for a nation
Different types of draught
Meteorological drought
- long term precipitation is lower than normal, affected by the atmospheric conditions
Agricultural drought
- not enough soil moisture to allow enough crops to grow, groundwater levels affect this
Hydrological droughts
- when surface and subsurface water is at a deficit, caused by a lack of precipitation
Socio economic droughts
- water demand outstrips the water available, caused by human overuse of the source
US drought - california (2015)
climate has mountains which affects rainfall
population is 40 million meaning there is pressure on water supplies
huge agricultural sector meaning there is high demand for water irrigation
lack of rainfall in this particular year meant supplies ran dry
El Nino Southern Oscillation
ENSO
Definition
- This is a large mass of warm water in the pacific ocean
This occurs guasiperiodically (regularly but not predictable) every 2-7 years. When it occurs it causes significant weather changes globally
The walker cycle
What it is
- Trade winds from the South American coast push warm water towards the Australian coast causing precipitation to take place here, it rises here due to low pressure where it then cools and condenses and return back towards South America
During El Nino
- trade winds lose their power as a result the precipitation moves towards the centre of the ocean, as a result when the water cools and condenses it is pushed in both directions (South America and Australia)
El Nino temperature impact
Drier - India and the east coast of the US
Wetter -
Mixed (seasonal reversal) -
EQ2
Lesson 7 - How do human activities increase the risk of droughts
How do human impact on droughts
Over abstraction of groundwater
- coca cola in kerela, wasn't enough water left for everyday needs and agriculture
Construction of dams, reservoirs and water transfer policies
- North south transfer policy project and the three gorges dam in china have attempted to change the countries water balance
Changing the land use and deforestation
- less vegetation mean less evapotranspiration causing there to be less atmospheric moisture
Australia 'The big dry'
Human causes
human activity contributed to global warming which affects the hadley cell
increased population in the east has put pressure on water supplies
Physical causes
el nino affected rainfall patterns
high relief in the east forms frontall rainfall so central areas lack rainfall
Impacts
50% of farmland was affected
reservoirs fell at around 40% full
High lack of water in Adelaide
Had to develop new schemes to provide a reliable water source
The sahel region
Seasonal
- this is a transitional climate zone so is drought sensitive
Annual
- rainfall varies from 100mm on the edge of the sahara-800mm along its southern margins. Also unusually warm ocean temperatures favour strong conventional uplift which weakens the West African Monsoon and increases droughts
Human causes of droughts:
overgrazing - when animals are eating too much greenland without giving it time to recover
Deforestation
Poor land management - unsustainable agricultural practices
Physical causes of droughts:
climate change
2002 drought caused by air pollution generated in Eurasia and North America
2005 sea surface temperature rises thought to have caused droughts
Countries involved: senegal, mali, burkina faso, algeria, nigeria, Cameroon
impacts of these droughts:
crop growth isn't possible due to lack of rainfall
jobs lost due to lack of cotton growth
less clean drinking water which leads to more diseases like cholera, this is caused from soil erosion which contaminates the water
people are having to travel further to get clean water which takes away time they have for education of work, continuing the cycle of poverty
locusts are eating food that people need, they consumer high quantities of food in swarms and infect lots of food which there is not a cure for which makes more people ill
Lesson 8 - How do surpluses within the hydrological cycle cause flooding?
What are air masses
Tropical
continental air masses is air mass over deserts, comes from africa
Polar
continental air masses come from the north pole and travels over land and not sea
Maritime
air mass is the most common in the UK, this travels over the ocean which warms the air, can lead to sunshine and showers
What are fronts
Definition
- this is the boundary between bodies of air with different temperatures and humidity
Warm front is a red line with triangles
Cold fronts are a blue line with circles
Black lines
are unstable air, these are unpredictable and can lead to intense rainfall
If the
isobars
are far apart then wind speed is low and weather conditions are static
Meteorological causes of flooding
Much of UK flooding if from mid latitude depressions forming from low air pressure
Bring showers to warm fronts and rain to cold fronts
Saturated ground leads to surface runoff meaning it moves quicker to rivers
Once the capacity is exceeded then the banks will break and water will flow onto the floodplain
Flash floods
Usually happen very quickly and without warning
they are intense (associated with thunderstorms)
Case study
: Sardinia (italy) caused 18 deaths and $1.14 billion in damage
Case study
: Boscastle experienced 8 hours of intense rainfall, 75 cars washed away and 100 homes lost, 175 people had to be rescued
Monsoons
Caused by seasonal changes in prevailing wind direction, In India and South East Asia, heavy rainfall between april to september
warm moist air from the Indian ocean moves towards the indian subcontinent, this makes the climate humid and causes torrential rain
Happens because the ITCZ moves northwards, driving low pressure further north bringing rainfall
around 70% over annual rainfall in 100 days
Snowmelt
In high latitudes snowmelt can add to a river capacity, this especially effects Asia and south america
lower regions remain frozen as there is not a high rate of infiltration
glacial outbursts release a lot of meltwater called jakulhaups
Other impacts
Soil depth
- deeper soil will have a higher capacity
Vegetation
- this aid in interception, storage and evapotranspiration which increases lag time
Rock type
- permeable surface will absorb water, impermeable surfaces will increase runoff
Tributaries
- over rivers joining could increase flow, adding to the risk of flooding
Slope
- steep slopes will increase surface runoff
Human causes of flooding
climate changes causes extreme weather
budget cuts in the amount of money spent on flood defences
poor land management, like blocking ditches
Lesson 9 - What are the impacts of flooding
Facts
from 1990-2010 there have been 3,000 floods recorded globally
they have affected half the worlds population
killed over 200,000
900 million are at risk and 75 million are annually affected
90% of all death and 50% of all damages occur in Asia
more frequently happen in europe and they have high economic impacts
Socio economic impacts
people can be affected multiple times by hazards
crops, livestock and infrastructure can suffer major damage
many people can be killed, especially in less economically developed nations for reasons such as people not knowing how to swim
Environmental impacts
can be positive for plants as when rivers flood they bring up nutrients
floods can also recharge groundwater systems
Eutrophication
- excessive richness of nutrients in a body of water, frequently due to a runoff from land, which causes dense growth of plants
Case study: 2007 floods UK
Flooding started in June, and hit again in July, this was the wettest July in UK record
56,000 homes and businesses were affected
30,000 homes have since been provided protection
The west of affected the worst, Wales
The UK's largest river, the river Severn had its banks burst on the 20th of July after a storm, 12 people were killed and cost £6 million in damages
Power supplies were damaged and water supplies were cut off
Flash flooding afterwards caused further damage
387mm of rainfall in 3 months
Case study: 2012 - the year that drenched britain
8,000 homes were flooded
200,000 properties were protected by defences
10 separate flooding events between april and december
£600 million lost on crops
devon and cornwall experienced 200 mm of rainfall in one day
Case study: Storm Desmond (2015)
flooding was caused in: North-West England, North Wales, Southern Scotland, and Northern Ireland
rivers in cumbria exceeded the highest discharge levels on record which was 341.4mm
power cuts and trains were disrupted
5,200 homes were flooded in cumbria
government paid £50 million out to people to make their homes resilient to flooding
Lesson 11 - How does climate change affect water security
The global water supply is affected by
biogeochemical feedback - includes: biological activity, atmospheric, water or soil chemistry
ENSO - sunspots cycles, and biogeochemical feedback mechanisms
Climate change scenarios predict that in the near future
precipitation will become more variable
increased risk of floods and droughts
increase in water security of water supplies
Future trends
2010 was the UK's wettest ever year recorded, strongest el nino on record which caused an intense la nina event which destabilised atmospheric conditions and set the stage for increased precipitation and flood events
flood figures are not becoming more common but are becoming more extreme
droughts have become more widespread and affected more people
Future issues
food and water supplies will be affected
ecosystems will be under threat
increased risk of flooding and drought
Projections for the future are complex for several reasons:
there are multiple causes of climate change
long term climate change data is limited so hard to analyse
insufficient understandings of the teleconnections of the earths systems
Water scarcity
Physical water scarcity
- this is when there isn't enough water to meets everyone's needs. This is caused by: low levels of rainfall, high rates of evaporation and population strain
Economic water security
- they cannot afford the infrastructure to bring fresh water to everyone. This is caused by: poverty and people cant afford pipes or pumps
Projected water scarcity in 2025
- these are countries that have issues relating to each of these water scarcity factors
Physical water scarcity
- South Africa, India and China
Economic water scarcity
- Australia, Argentina and New Zealand
Little or no water scarcity
- Russia, USA, and Canada
case study - California
causes
physical
human factors contributing to climate change increasing global temperatures
precipitation patterns changes are seeing areas of high atmospheric pressure is diverting wind storms preventing them from reaching california
Insufficient distribution system are meaning that water is losts during winter storms when the river flow exceeds the capacity of the water pumps which move water from north to south
human
urbanisation is causing there to be more fossil fuel emissions
lack of new infrastructure to preserve water supplies
High levels of agriculture - cattle ranching increasing the amount of methane that is released into the environment which contributes to the enhanced greenhouse effect
impacts
social
many californias are being forced to live with less water
water theft is an issue
people are replacing their grass with artificial turf
economic
wildfires breaking out destroying peoples homes and livelihood
water prices become higher due to a shortfall in supply
agriculutre will be affected as the dryer conditions will prevent crop growth
Political
overpopulation concerns because of socio-economic droughts
legislation will have to be put in place to limit water usage during drought periods
political confrontations could be caused as they do not yet have an established plan for approaching this issue, so deciding on an approach is likely to be divisive
management
they have planned a reservoir that will project that will provide 600 billion litres of water every day
they have invested $1 billion into drought relief which will save 1.5 million acres of water in the next nine months
water restrictions are placed on households and companies when experiencing droughts
Environmental
forests and habitats are being destroyed by wildfires
hydrological energy providers cannot be used, subsequently nuclear energy has to be used instead which increases pollution
crops are likely to die if they cannot be provided with sufficient amounts of water
Lesson 11 (Part 2) - What is the pattern of global water insecurity
According to the UN
water use has grown twice as fast as population growth in the last century
by 2025, 1.8 billion people will be living in areas with absolute water scarcity
two thirds of the worlds population could be living under water stress conditions
Water stress
- if renewable water sources are between 1,000-1,700m cubed per capita then a country is experiencing water stress. this often leads to restrictions on water use and conflicts caused
Water scarcity
- if renewable resources are between 500-1,000m cubed per capita then a country is experiencing water scarcity. Usually open tensions and conflicts
Absolute water scarcity
- If renewable resources are very low ( below 500m cubed per capita) then there will be widespread restrictions on usage
Demand for water is increasing
the world population is increasing by 80 million per year
changes in lifestyles and eating habits are using more water
production of biofuels has increased (1 litre of biofuels takes between 1,000-4,000 litres of water to produce)
80% of diseases in developing countries are associated with water, causing nearly 3 million deaths per year. for example nearly 5,000 children die from diarrhoea every day
EQ3
Lesson 12 - What are the causes for global water insecurity
Notes
only 50% of water supplies are used, the issue lies within 12% of the worlds population consuming 85% of all water consumed
population increases in areas where there is limited water supply causes pressure
population has increased 4 times in the last century, but water consumption has increased by 6 times
Physical factors
climate determines the global distribution of precipitation patterns with air pressure affecting this, low air pressure are water secure
topography and distance from the sea, high runoff and surface storage are contributors
geology controls aquifers (water bearing rocks) that provide groundwater storage, impermeable surfaces lead to runoff into lakes
Human factors
Pollution of water supplies, through untreated sewage and chemical fertilisers entering
Over abstractions of surface and groundwater, for domestic, agricultural and industrial use
Irrigation makes the water more saline, as when crops leave behind salt which accumulates in soil and over time in water
Lesson 13 - How is a rise in demand for water increasing water insecurity
Case study - California
What is causing and increasing the problem?
lack of winter storms and record high temperatures
when surface water supplies are low underground water supplies are relied on to make up for shortfall, these take a long time to naturally refill
who are the key players?
farmers - almond crop
fracking - oil industry
growing affluent population - increasing the use of 'white goods" (electrical goods)
How is climate change impacting water resources?
the ENSO leads to a lack of rainfall, which water resources rely on
higher rates of evapotranspiration which is caused by increasing temperatures, thus reducing the availability of water
Lesson 14 - what are the risks and consequences of water insecurity
The water poverty index: UN definition
- A means of monitoring and prioritising water needs in response to the UN millennium development goals that address poverty and water access
Key terms:
Water resources
- the physical availability and quality of water
Access to water
- the distance from safe water for drinking, cooking, irrigation and industrial use
Handling capacity
- effective management, infrastructure and income
Use of water
- for domestic, agricultural and industrial use
Environmental indicators
- the ability to sustain nature and ecosystems
Nearly 20% of the world population lives in water scarcity
low rainfall
human acitvites
climate change
Collecting, storing and distributing water is expensive as it requires robust infrastructure - this is a problem for nations that are poorer and have high population density
In many poorer nations people suffer from economic water scarcity as they cannot afford water. For example in the UK 50L of water costs the average person 0.1% of their daily salary, whereas in ethiopia it costs 15%
The price of water
- in many countries the water supplies are controlled by the private sector and not by the government, because of this consumers can be charged more
For example ireland's water is 75% cheaper than in the UK
The pacific institute - they say that " water is too important to human health and the health of our environment to be placed entirely in private hands"
Case study: Bolivia
- In 1999 the city of Cochabamba had its water supplies taken over by Agua Del Tunari, the company raised the prices so that it costs 20% of the urban poor income. But after 4 days of protest the contracts was cancelled
Why is water so important?
Essential for human survival and the economy as it is used to produce goods and services like food and energy
economic - its use in manufacturing is set to increase by 400% by 2025 as our demand for food continues to increase with changing consumer habits as well as population growth
social - 800 million people still lack of access to clean water, this is down to a lack of investment into water infrastructure within some nations. For example - 335,000 children die annually in Nigeria from water related diseases
Lesson 15 - How do shared water supplies create conflicts
As demand for water and water shortages rises then the potential for conflicts to be caused over water supplies increases too
conflict can occur from economic development varies along a river, some countries take more out for irrigation, industrialisation and human use
For example:
china vs myanmar, laos, thailand and vietnam
- the construction of dams along the chinese section of the mekong river reduces flow to nations downstream
Example: Turkey, Syria and Iraq
Due to regional variations in water supplies the country has introduced the GAP project costing $32 billion USD
The attempted to to improve the water supplies in Anatolia (South East Turkey) but this created conflicts with Syria and Iraq due to the construction of dams along the Euphrates and Tigris which can provide them with water
Case study : Australia - The murray darling basin
extraction in the basin has increased 500% ince 1920
due to variations in australia's climate the rainfall varies, when combined with the ENSO this becomes even more uneven
key players: local state and government, industrial users (miners) and urban residents
Facts
2 million residents
1 million square kilometers
14% of Australia's water
Provides 75% of australia's water
provides 40% of their farm produce
The basin plan
The overall goal is to cap water use along the river so it is not over allocated for different stakeholders therefore it doesn't lead to conflicts
Basic principals (Summary)
To allow water to be purchased on behalf of the environment, and to allow water permits to be traded between irrigators depending on relative need
Clash between states water management responsibilities
Responsible for enforcing these rules and making sure that rallocations are not exceeded
This plan is built on a foundation of trust and transparency
The buyback scheme has transformed water into a tradable commodity worth $2 billion a year
Water trading has also helped make water more flexible
The Nile basin
Countries involved
: Burundi, Rwanda, Egypt, Ethiopia, Kenya, Sudan, Tanzania
Future tensions:
population of those who live within the basin will double from 300-600 million by 2030
Susceptible to El Nino and La Nins cycles
Dam proposals are likely to cause further issues due to how it affects the downstream flow
History of the Nile
- Sudan and Egypt has had almost all control over this water source in previous years, with other countries having to rely on evaporation to provide them water. In the modern day these other nations have come to an agreement to give them more power over the Niles use
New plans for the niles water
Egypt
- an irrigation scheme that will irrigate 220,000 hectares and Salem canal that will divert water to northern Sinai
Sudan
- the Merowe dam and Kajbar dam construction
Ethiopia
- 33 proposals for irrigation plans to make the country an exporter of HEP and food (it will block sediment and reduce flow downstream)
Lesson 16 - How can we use hard engineering and sustainable approaches to managing water
Hard engineering case studies
The three gorges dam (Yangtze, China)
Outline: designed to control flooding in Yangtze, improve water supply
Pro: Electricity generated for HEP is crucial for China's growth
Con: 1.3 million people had to be relocated from 1,500 towns and villages
The South North water project dam (Beijing, China)
Outline: Beijing region has 35% of china's population and 40% of arable land, but only 7% is water
Pro: will reduce the amount of groundwater abstracted
Con: 345,000 people will have to be relocated
Desalination in Israel
Outline: desalination plants provide a predictable water supply
Pro: Produces up to 600 tonnes of potable water per hour
Con: each plant requires its own power station which emits CO2
Sustainable management approaches
Israel
issues: has a poor climate and geographical position for adequate water supplies, they also have political issues over the West bank aquifer
How it is sustainable: charging real value prices for water to reflect supply and ecosystem management, they import food with high virtual water content to save on agricultural demands, they are the biggest user of recyclable water in the world
Singapore - Holistic management
issues: the 5.4 million residents of Singapore are all urban, thus the demand for water is high
How it is sustainable: metering water so people do not waste it, cutting water leaks to 5% (UK's is 20%), water prices fall and rise with usage
Four taps approach
Branding of recycling water - NEWater
Importing water (from places like Malaysia)
Desalinating water (like in Israel)
NEWater
This is high grade reclaimed water
It is treated used water that is further purified using advanced membrane technologies and ultra violet disinfection
allowing it to be safe to drink
Case study: Uganda - rainwater harvesting jars
Wateraid have trained local building to construct rainwater harvesting jars
Benefits
They are made from local materials, which allow it to be durable and last for a long time
one jar can hold 1,500 litres of water
it is collecting from roofs and used during the dry season
It is an intermediate technology as it is appropriate for the countries level of development
Lesson 17 - What are the different approaches to managing water supplies
IWRM (Integrated Water Resource Management)
This is a coming together of local and global groups to find policies and strategies to manage water in a way that will benefit all stakeholders
Some aims are:
Freedom from corruption
Effective pricing of water resources
Open conversations between water providers and water users
Regulating the planning and use of water sources
Protecting the environment and ecosystems
Example: Gujarat, India - Intermediate technology has been used to provide a year round supply of water. Also, India and Pakistan now have a water sharing treaties which would presumed unlikely due to their hostility
Enabling tripple cropping
Quadroupling production per heactare
Raised household incomes fivefold, higher than the Indian average
Business as usual
- consumptions of resource would continue at the rate it already has
Sustainable management
- the usage of the source would reduce, whilst the price would increase
Radical action
- this would mean to put strict rules in place to control the resources usage
Case study - The Colorado River Basin Management
It supplies water to 8 states
Has 11 major dams
Covers 1.4 million hectares of farmland
Provides drinking water for 50 million americans
Since the 1990's the annual flow has decreased by 15%
There has been persistent drought since 2000
Agreements:
2007
- instead of sharing the basin, the states would divide up the shortages and the amount of water available would determine the supply
2012
- Was signed by the US and Mexico, to allow Mexico to store some of its colorado water in the Lake Mead, in return the water providers in the colorado basin will be able to purchase water conserved through improving Mexico's canals and storage infrastructure
Controls flooding and provides HEP