water - hydrological cycle and drough (copy)

hydrological cycle

Globally it is a closed system but smaller seas can never be a fully closed system

Hydrological cycle consists of 4 things

Stores- water is held

Flows- water is transferred

Fluxes- rate of flow between stores

Processes- physical mechanisms which move the water e.g. evaporation, precipitation

Hydrological cycle diagram

weren’t shown on diagram =

-Surface runoff flux data - infiltration and underground flows

-No infiltration

-Groundwater in not numbered as a store

Difference between blue and green water

Blue = visible water in the cycle e.g. rivers and lakes

Green= invisible water in the cycle e.g. water stored in vegetation or beneath the surface in the soil

what is the circular flow shown in the oceans e.g. 40,000km³ per year/ 40×10km³ per year

-thermohaline circulation ( convection currents driven by temp change and salinity)

-important because they drive heat around the earths oceans and effect climates

World water stores

Oceans = 97% - inaccessible due to salt- desalination= expensive

In the other 3%=

Freshwater=2.5% but 69% of freshwater is stored as glaciers and icecaps so inaccesbile due to being a solid form and isolated location+ resident time= 20-100yrs for glaciers and longer for ice caps but meltwater= only water source for some mountain communities

Surface and other freshwater= Mainly ground ice and permafrost- shallow groundwater stores = accessible from wells but deeper= less accessible and some stores are fossil so finite - Mediterranean limestone islands

Accessible surface freshwater= less than 1% and Mainly in Lakes- Natural and artificial but lakes and rivers are only 0.01% of worlds water

Some of freshwater is take up by plants( green water) and atmosphere and soil

Residence time

How long water remains in a store- important because it impacts the turnover within hydrological cycles

Longest residence time = oceans and shortest = atmosphere then icesheets/caps and then rivers

Only an estimate because there is variation within stores

Aquifers

Areas of significant groundwater storage normally in rock pores

And are recharged through precipitation and subsequent infiltration and percolation.

Fossil aquifers are ones that are no longer recharged possibly due to being trapped under a impermeable layer of rock or climate change

Drainage basin definitions

Drainage basin- The area of land drained by the river

Source- point where river starts

Tributary- A smaller river meets lager river

Confluence- where two tributaries meet

River channel- The eroded path of the river, consists of bed and banks.

Watershed- Boundary of a drainage basin

Important drainage basin hydrological definitions

Percolation- After infiltration and is the downwards movement of water through soil to groundwater zone.

Evapotranspiration

Precipitation

Aquifer- a layer of permeable rock that acts as a underground store of water

Infiltration

Evaporation

Groundwater- percolated water that is stored deep below the surface

Water table-Uppermost level of saturated groundwater zone

Local Hydrological cycle diagram

Physical factors effecting drainage basins inputs flows and outputs

• climate

• soils

• vegetation

• geology

• relief

  Have a go at a brief explanation of influence of each factor

Human factors effecting drainage basins inputs flows and outputs

• Deforestation

• Urbanisation

• Water abstraction

• Dams

  Have a go at a brief explanation of influence of each factor

How does solar radiation change across globe

Global energy budget- shorter wavelength near equator = higher temps

Temp variation with latitude- nearer equator = less atmosphere for radiation to pass through and radiation is more concentrated.

Temp effecting Air movement which effecting precipitation

hot air rises and cools and cant hold as much water vapour= low pressure + high rainfall (vise versa)

Global circulation model= Hadley, feral, polar

Also wind direction effects precipitation patterns as surface winds blow from high to low pressure and create trade and westerly winds and onshore winds create higher precipitation.

types of rainfall- convectional

- Land becomes hot= air becomes hotter + rises= starts to cool as rising and ability to hold water vapour decreases= precipitation

• common in equatorial areas and UK in very hot summers

Types of rainfall- orographic

- air forced to rise over barrier (mountain)= air cools and condenses= rain + leeward /downwind slope receives little rain (rain shadow)

Type of rainfall- frontal / cyclonic rainfall

-warm air= lighter and less dense is forced to rise over cooler more dense air= as it rises it cools and ability to hold water vapour decreases=condensation + cloud formation = rain

Global water balance

• highest rainfall= equatorial = convection rainfall + more precipitation than evaporation= large surface runoff = positive water balance

• Tropics= lower rainfall + higher evaporation= negative water balance

• Mid lats= positive water balance

• poles = higher pressure + low rainfall but little evaporation = slight positive water balance

  LINK TO GLOBAL CIRCULATION (LOW PRESSURE = HIGH PRECIP)

Potential evpotransipration

Amount of evaporation that would occur is their was a sufficient water source available

• example : Sahara= high potential evapotranspiration because of climate but low in reality due to lack of water stores

ITCZ ( inter tropical convergence zone) - diagram

ITCZ= migrating zone which moves with the movement of the overhead sun.

June solstice = ITCZ migrates Into Northern hemisphere

Equinoxes= sun overhead = in middle

December Solstice= Migrates to sourthern hemisphere

Eurpoe’s air masses diagram

2 most common= polar maritime= cool and moist (precipitation)

Tropical maritime= warm and moist (precipitation)

Together form mid latitude depressions

River regimes defintion and determitation

• Annual variation in discharge- seasonality- climate

• Primarily determined by climate of thee area ( rainfall (amount and distribution) and rates of evapotranspiration and snowmelt)

• Few UK rivers left with natural regimes due to land drain control of flow, finshing and recreation.

• Not the same as storm hydrography’s so not get mixed up

Things effecting river regimes

• winter water stored as permafrost or snow

• snowmelt in spring = increase in discharge

• UK= more deciduous trees= higher evaporation in summer and higher temps too.

• intense storms and convectional rainfall

• near equator= low pressure systems all year round.

Factors effecting Storm hydrographs

Valley side steepness

Soil type

Size of drainage basin

Vegetation

Human activity

HAVE A THINK HOW?

River Ock and River Lamborn STORM HYDROGRAPH EXAMPLE

Lamborn= steadier river- lager drainage basin + chalk so porous and water can flow through

Ock= Flashier river- Smaller drainage basin + clay= impermeable and small pores= less infiltration + percolation.

Both have same precipitation as are neighbouring

Drought definition

A period of abnormally dry weather that causes serious hydrological imbalance in a specific region.

-distribution of drought varies globally e.g. high in tropics and less drought along equator

Drought definition

A period of abnormally dry weather that causes serious hydrological imbalance in a specific region.

-distribution of drought varies globally e.g. high in tropics and less drought along equator

Types of drought

• meteorological= long term precipitation is lower than usual (precipitation deficit)

• Hydrological= deficiencies in surface and subsurface water supplies as measured in rivers, reservoirs, lakes and groundwater. Originates from lack of precipitation but can follow or come with Meteorological or agricultural drought ( stream flow/river channel flow deficit)

• Agricultural= In sufficient soil moisture to meet demands of particular crop at particular time. A deficit of rainwater over cropped areas in critical periods of growth can cause crop failure. (soil moisture deficit)

• Famine= Widespread failure of agricultural systems, food shortages develop in to famine and have severe social, economic and environmental impacts. (food deficit)

Global atmospheric circulation system process

• Intense solar at equator= warm air= rising= air cools= condenses= rainfall

• Subtropical high pressure from sinking equatorial air = belt of high pressure dry+ hot

• Air returns to equator at ground level creating trade winds

• Trade winds meet ITCZ. ITCZ moves with seasons. This movement causes alternating wet and try seasons in tropics ( seasonal rain)

• Warm air = mid latitudes to subtropics meets cool polar air at polar front= less dense warm air rises causing condensation and rainfall

• Warmer air rises into polar front jet stream and is transferred at high altitude towards poles= cools + sinks= ground level movement o air towards mid lats.

How does global circulation cause drought in Sahel

Tropics= high pressure = low rainfall (associated with Hadley cell)

Migration of ITCZ results in wet season in summer months as ITCZ shifts northwards with overhead sun.

Sometimes tropical high pressures associated with descending air from Hadley cell block the high humidity= blocks arrival of wet season + serve drought can occur.

Mid latitude Anti-cyclone blocking

High atmospheric pressure where air is sinking - high pressure= stable= blocks low pressure systems such as cyclones which bring precipitation= results are dry stable weather.

Oceanic components need for El Nino

• El Nino occurs when sea surface temps are +0.5 higher than average.

• This increase represents a huge store of energy in the deep ocean and can sustain a ENSO event.

What are El Nino Southern Oscillations

When the climate system around the equatorial Pacific undergoes irregular change every 3-7 years. The surface waters of ocean interact with atmosphere and change occurs (coupled ocean-atmospheric systems). A positive feedback is created which amplifies small changes in ocean temp.

Oceanic components need for El Nino

• El Nino occurs when sea surface temps are +0.5 higher than average.

• This increase represents a huge store of energy in the deep ocean and can sustain a ENSO event.

Atmospheric components needed for El Nino

• Air pressure changes in response to sea surface temp change

• If pressure gradient (the difference between High and low pressure) decreases then winds = less strength and can even reverse direction.

• The wind pulls a huge cell of warm water across Pacific from W to E during an El Nino.

Impacts of ENSO

• Causes drought conditions in Australia and Indonesia

• And flood conditions in South America.

• Also has knock on impacts on other parts of world due to global temps being higher in El Nino years and lower in La Nina years.

El Nino year circulation + impacts

• Trade winds weakened significantly+ sometimes reversed

• Less surface water moved E-W so AUS NE coast = cooler= high pressure + less rainfall+ potential for drought

• Surface of E pacific= warmer than usual and cold water is unable to well up from deep = warmer= rising air= lower pressure= higher rainfall than usual in South America+ potential for floods

  IF SURFACE WATER IS ALOT WARMER THAN USUAL = GLOBAL TEMP RISE

2015-16 El Nino impacts

• Australia- Low rainfall = drought and bushfires

• South America- Hit by worst floods in 50yrs and over 150,000 people forced to evacuate.

• Pacific Islands- Drought conditions in west pacific= 4.7m people effected

• Ethiopia- Severe drought= 80% of harvest failed and affected 22m people.

Neutral year circulation + impacts with diagram

• Trade winds E to W across pacific

• warm surface water moves E to W and pools of coast of Aus. = rising warm air= instability= low pressure= rain

  -Norm in AUS= High rainfall on NE coast

• cold waters from deep wells up of coast of South America= air cools= stable air conditions= high pressure+ little rain

  -Norm in South America= Arid climate on west coast

El Nino year circulation + impacts

• Trade winds weakened significantly+ sometimes reversed

• Less surface water moved E-W so AUS NE coast = cooler= high pressure + less rainfall+ potential for drought

• Surface of E pacific= warmer than usual and cold water is unable to well up from deep = warmer= rising air= lower pressure= higher rainfall than usual in South America+ potential for floods

  IF SURFACE WATER IS ALOT WARMER THAN USUAL = GLOBAL TEMP RISE

Human Actions that Exacerbate flood risk

• Urbanization- Impermeable surfaces,

  straightening river channels, change in land use associated with change in agriculture, urban areas tend to be low lying= flood risk

• Deforestation- less interception, less storage, less transpiration, less soil structure= decrease in lag time= increased flood risk

• Changing farming practice- Deforestation, ploughing, over grazing, drowning of wet land for agricultural use + normal upstream from urbanized areas= knock on effect downstream urban areas = increased flood risk= downstream knock of effect (snowball)

La Nina year circulation + impacts

• Trade winds blow stronger E-W

• Warmer surface water E-w and pools off coast of AUS in even greater quantities than usual= more rising air= more unstable= very high rainfall= flood conditions

• More cold water wells up in E pacific- off coast of South America = more stable= less rain than usual = drought conditions

Meteorological Physical factors that cause flooding

Meteorological = short term weather events

• Prolonged and heavy rainfall = cumulative effect on drainage basins= extreme flooding (eg UK associated with Depressions+ degree of flooding depends with pattern of depression)

• Extreme monsoonal rainfall- Dry most year + then intense short period rainfall ( around 70% of rainfall in 100days) so low lying land= floods + landslides (eg Bangladesh- low lying = flood / Pakistan 2010 =flashfloods + landslides

• Snowmelt- Late spring= melting= can cause intense flooding (eg Extensive snowmelt flooding continental interiors of Asia + America)

• Ice melt- Snow melt sometimes held up by temporary ice dams but when these melt= catastrophic draining of glacial lakes (eg. Himalayas= glacial outburst floods due to ice melts = catastrophic glacial lake drainage

Human Actions that Exacerbate flood risk

• Urbanization- Impermeable surfaces,

  straightening river channels, change in land use associated with change in agriculture, urban areas tend to be low lying= flood risk

• Deforestation- less interception, less storage, less transpiration, less soil structure= decrease in lag time= increased flood risk

• Changing farming practice- Deforestation, ploughing, over grazing, drowning of wet land for agricultural use + normal upstream from urbanized areas= knock on effect downstream urban areas = increased flood risk= downstream knock of effect (snowball)

Flooding in UK-River Greta

• two main watercourses running close to Keswick are The River Derwent and River Greta. And since 1822 approx. 20 significant flood events have been recorded.

• 2005- 75yr flood. United Utilities pumping station failed and sewage leaked in 35 houses.

• 2009- 70yr flood flooding 250 houses

• 2011-12- Keswick flood risk management plan created and 77yr flood

• 2015- river Greta overtopped flood defences

South Asia v UK floods- reasons for differing impacts

• Capacity to cope- Less capacity in SA lower GDP and corruption and trans boundary river systems

• UK is associated with mid latitude depressions and river flooding and SA associated with heavy rainfall on monsoon season

• Infrastructure + dev. - UK is developed and SA= less so more likely damage in SA

• population density- Bangladesh pop density= 1,265 people per km² compared to cumbia= 74 people per km²

Causes of flooding in South Asia ( Nepal, India, Bangladesh)

• monsoon rainfall-June-sept ( 80% of S Asia rain)

• Snowmelt-March-June in Himalaya + Tibetan Plateau, particularly effects Brahmaputra

• tropical Cyclones- April-Dec (ocean temps over 26)- Particularly effects Bangladesh

• Relief- Himalaya-steep slopes but Bangladesh= low lying( less 3m above sea)

• Deforestation- Eg 1990-2005 Nepal lost 24.5% of forest cover

• Population Growth and urbanization- High (eg. Bangladesh 1960= 50m/ 2016-163m)

Example of flood history in Bangladesh

flood are a regular occurrence examples:

• 1987- 60,000km²of land and a 30-70yr event

• 1988- 80,000 km² of land land 50-100yr event

• 1998- 75% of total area of the country including half capital city +30m homeless

Key impacts of 2017 South Asian floods

• In India- Bihar- Death tole over 500 and flood effect over 17m people in India

• Mumbai (India)- streets flooded and public transport paralysed. Mumbai is trying to make itself global financial hub but city is struggling to cope in annual monsoon season

• Nepal- 90000 home destroyed and 1.4m people affected

• Bangladesh- 7.1m effected in Bangladesh and 600000 farm land damaged which the economy relies on.

Flooding in UK-River Greta

• two main watercourses running close to Keswick are The River Derwent and River Greta. And since 1822 approx. 20 significant flood events have been recorded.

• 2005- 75yr flood. United Utilities pumping station failed and sewage leaked in 35 houses.

• 2009- 70yr flood flooding 250 houses

• 2011-12- Keswick flood risk management plan created and 77yr flood

• 2015- river Greta overtopped flood defences

South Asia v UK floods- reasons for differing impacts

• Capacity to cope- Less capacity in SA lower GDP and corruption and trans boundary river systems

• UK is associated with mid latitude depressions and river flooding and SA associated with heavy rainfall on monsoon season

• Infrastructure + dev. - UK is developed and SA= less so more likely damage in SA

• population density- Bangladesh pop density= 1,265 people per km² compared to cumbia= 74 people per km²

Why is there uncertainty over the impact of climate change on the global hydrological cycle?

• uncertainty of impact of climate change due to uncertainty over future temp change

  Highest projection for year 2100 is increase of 5.4 and lowest= increase 0.25

• Also climate change is only one process modifying global hydrological cycle there is also human impacts eg deforestation. And it is hard to split the human impacts from climate change impacts

Human Factors effecting likelihood of drought CASE STUDY- SAHEL

• In Sahel there were many human factors that exacerbated the drought conditions. (Human factors don’t cause meteorological drought but enhance its impacts)

• In Sahel GPD is low, national debt, population growth is exponential so agriculture is under increasing pressures to feed and help pay off debt.

• PHYSICAL FACTOR- Less rainfall= increased drought + Global Warming = less reliability of rainfall= vegetation dies…

• Human- Increase in animals (above carrying capacity of fragile grasslands= overgrazing (soil depleted of nutrients) = vegetation cannot reestablish itself….

• Pop growth- Farmers forced to use more land for food + cash crop = overcultivation= reduced soil fertility+ veg. removed ….

• Immigrants- increase in demand for wood for cooking, heating + buildings- Deforestation- veg removed….

• …. Decrease in protective veg. cover= soil exposed to wind and rain so erosion= Increase in evaporation from soil - possible salination= increase risk of soil erosion= DESERTIFICATION

What human factors increase the likelihood of drought - CASE STUDY- MURRAY-DARLING - SOUTHEAST AUSTRALLIA.

• AUS. most important food-production region (40% of all farm produce- £20b). Agriculture accounts for 60% of AUS. water consumption

• Irrigation schemes began 1887, series of reservoirs + canals to redistribute water from MD to more arid areas.

• Av. only 54% of water flowing in river reaches mouth + lower in drought years.

• Contamination- Much of bedrock under MD is rich in salt. Excessive land clearing + saline groundwater (gets used) = water contaminated with salt

How may precipitation change, resulting in increase flooding and drought?

• Increased temp of land + sea surface= more evaporation + atmospheric moisture= more intense short periods of rainfall = floods

• Increased temps= more intense high pressure systems= reducing rainfall= causing drought

• Increased evaporation= reduce in surface store (if not replenished)= Hydrological drought

• Increased sea surface temps= Intensification of El Nino cycles= intensified extremes.

• CLIMATE CHNAGE= INCREASE IN BOTH EXTREMES

Other hydrological cycle components change as result of climate change

INCREASE

• Evaporation, Transpiration

DECREASE

• Permafrost, snow, ice, oceans

INCREASE+DECREASE

• Run-off/ stream flows= increase in drought + floods

Examples for a RIVER REGIME QU

• Nile - Blue Nile= summer discharge due to movement of ITCZ meaning low pressure + high rainfall in summer- there is low rainfall for the rest of the year

• High latitudes- eg N. Russia- Winter= all precipitation= snow and rivers = ice but spring= meltwater= huge spike of discharge in spring/summer

• Monsoon- pronounced peak in river discharge in Summer- Ghanges

• Bramaputra= summer peak but earlier due to snowmelt

• Uk- mid lats = winter precipitation + high evaporation in summer means winter= peak of discharge

Why is there an uncertainty over the impact of climate change on the global hydrological cycle

• uncertainty of future temp change

• Highest projection for year 2100= increase of 5.4 and lowest= increase of 0.25

• The higher the prediction the more extreme the changes are likely to be, including the extent to which drought and flooding intensifies

definition of water security

• the capacity of pop to safeguard sustainable (future too) access to adequate quantities of acceptable quality of water to sustain livelihoods, human well being and socio-economic development, for ensuring protection against water- borne pollution and water related disasters and for preserving ecosystems in a climate of peace + political stability

• Add pic

Water stress+ scarcity definitions

Stress- when annual supply of water per person falls below 1700m³ (point of shortage)

Scarcity- when annual water supply per person falls below 1,000m³ (shortage). BY 2050 1.5b of world pop will be experiencing water scarcity

Physical causes of water scarcity

• Higher rainfall at equator than poles + tropics= determined by global circulation= limited rainfall=basis for insecurity

• Sahel- less rainfall with time (due to climate c?) = limited rainfall supply= insecurity basis

• Senegal + Pakistan- seasonal rainfall dur to ITCZ + monsoon + so seasonal drought

• River Colorado- Annual discharge= fluctuates +- 15 but slight pattern of decrease (climate change?)

• Storage in major global aquifers= decrease= insecurity

• saltwater encroachment due to rise in sea level/ increase storms= limits freshwater supply= insecurity

Human causes for water insecurity

• Western Europe, eastern China, India= large pop= large demand/ Sahel= marginal area + demand= insecurity

• increase world pop= demand increase= over abstraction

• higher standard of living in Europe, USA, Aus., Canada= demand increase (excessive use creates insecurity)/ less developed areas= less access= insecurity

• Income higher globally= use more water= domestic demand increase

• India (developing)= main use= agriculture due to overpopulation + primary sector demand= pot. insecurity

• Agriculture, industrial, domestic all waste water= polluted= less supply= insecurity + increase demand in each sector

What is water insecurity

when demand outweighs supply

Why do water prices vary

• length of transporting water effect price e.g. Arizona= piped over 400km from River Colorado

• Availability effects price e.g .water price significantly increased in recent California drought

• Developing meg cities=(insufficient infrastructure= due to lack in gov investment + rapid pop growth= increase demand. e.g. Informal water vendors in Philippines 4x more expensive than tap

• Players involved in supply water (urban areas tend to be supplied by private water companies= expensive) e.g. Colombia= companies charge highest prices in world vs Cuba gov subsides water to make affordable

• Privatisation of water e.g. Bolivia transferred to Us affiliated private water= dramatic increase in price

Definition of physical water scarcity

more than 75% of country/ regions blue water flow are bring used

• SW USA, SE AUS, North African Coast

• climate: low precip/ seasonality, climate change, rapid pop growth, usage- main factor= low precip= effects supply

Definition of economic water scarcity

Blue water flow is limited by lack of capital (money), tech + good governance

• Large areas of Africa (Sahel), S America

• wealth, water cost, factors are human but pressure accentuated by some physical factors so both importantWater u

What is global pattern of water scarcity

Picture

Water usage by agriculture sector

• greatest use of water globally

• Egypt- Desert environment= rely of irrigation= 86% of Egypt’s water use + complex infrastructure

• P= essential for food product= economic growth

• N=water conflict (especially Transboundary)

• N=Environmental issues- salinisation of soils due to excessive irrigation + evaporation

Water usage by industry sector

• 20% of all water withdrawals

• Drink manufacturing= 140l to produce 1l of soda + 300l to produce 1l of beer

• P= essential for production of range of goods, drinks, food= economic growth

• N= conflict between economic + social water needs

• N= water polluting form chemicals= ecosystem damage + human health threats

Water usage by energy sector

• Over 50% of energy usage of water= HEP + nuclear

• HEP= large stores of water in reservoirs

• Nuclear= cooling fuel in reactors

• Fracking= high pressure water to flush out gas- USA,CAN

• P= vital for economic growth

• P=these fuels contribute less to Climate change

• N= water conflict (HEP of transboundary water)

• N= warm water from Nuclear= ecosystem damage

• N= fracking= chemical pollution of rivers in accidents

What can inadequate water supply do?

= easily impede any water dependant aspects of economy e.g. 2021 drought cost California agriculture $1b and nearly 9,000 job

Inadequate= cost public (see before notes)

Water usage v GDP per capita

• usually positive correlation e.g. USA- water usage of 1,000m³/yr because of high GDP (40,750)= high standard of living= demand

• Norway= high GDP but low water usage as they rely on imports of agricultural + industry products from other countries

Water issues in El Salvador caused by economic dev

= most densely pop country in Central America + regions lowest water reserve due to unchecked commercial exploitation

Nejapa aquifer= countries main water source is being exploited by local Coca Cola bottling company + other companies + sugar cane plantations- store has dropped 20% in 5yrs, resulting in rationing for domestic water (but big business = unaffected)

Large areas of surface water= contaminated by industrial + Agri waste

Desperate situation for locals (1/3 households having no/little access to water)

Access to water + sanitation facts

Percentage of people not using improved source of drinking water- lowest= democratic of public (40%)- Central Africa= lowest levels of people using improved

Percentage of pop using safely managed sanitation facilities= more dev countries= more sanitation facilities/ lower in S America, C Africa + SE Asia

Percentage of people practising open defecation levels- Central Africa= highest

1 in 4 people still lack safely managed drinking water at home

Contaminated water= water borne disease e.g. cholera

1.7b use drinking water contaminated with faeces

1.4m lives lost each year to inadequate water, sanitation, hygiene

Factors about Chinas water

China= 7% of worlds freshwater but needs to meet needs of 19% of world pop

2/3 Chinese cities don’t have enough water all year round

China uses irrigation for 70% of food mostly in N + NE where Yellow river is running dry

National levels of water in China likely to reach stress levels by 2030

Factors causing water insecurity in Beijing-Tianjin area

Supply

Demand

-NE China- prone to floods + in recent years drought -Most precip falls July-Sept + several wet years can be followed by several dry years -Beijing= 60% of water from aquifers - OVEREXPLOITED (due to high demand) by water qual is still ok -Tianjin relies on groundwater for 30% of water supply but salt water encroachment on coast makes water brackish -Surface water supply depends on 5 major rivers which are heavily contaminated

-Beijing= 16m + Tianjin= 11m pop -Tianjin= major port, heavy industry(demands lots of water) -Both= pop growth stabilising around 2.5% but rural-urban migration is still high -Beijing 1970/80= series of drought- increased demand + low supply= lowered water table in some areas by 40m -Water demand in Beijing-Tianjin region= 4.9bm³ per year -Fastest rate of increase= domestic- now averages 240l per p per day

Summary of 3 Gorges Dam project

• world largest hydroelectric scheme

• China currently relies on coal fired power for over 70% of power so hydroelectric= clean energy + supports rapid industrial growth (but not enough HPE to meet scale of mass industrialisation)

• However social + environmental coasts are already apparent well before economic advantages are seen

Pros + Cons of Chinas 3 gorges project

	Benefits	Costs
Social	Flood protection could save many lives (Yangtze has history of floods, Dam= better management of floods)	Dammed water= drowning 100,000 hectares of farm land, 13 cities + 1,500 factories + heritage sites lost 1.9m displaced
Economic	18,000 MW of electricity (could save 50m tonnes of coal per year) Supply region responsible for 22% of China’s GDP
Environmental		High Ecological impact on fisheries, biodiversity + habitats Pollution increase in water as factories + mines are flooded River= large sediment load= could damage turbines + sediment stave downstream

Assessment of Cost ben of 3 gorges dam- China

• cost ben shows overall economic ben- cost= 70m + ben= 140b= 1.55 positive ratio (but around 25yrs before money made on dam due to cost + reservoir will take years to fill so years for it to be economically viable

• but this doesn’t include environmental + social cost ben which show overall negative which shouldn’t be ignored

• social + economic costs will be seen well before economic bens

Summary of Chinas South North Transfer project

• attempt of redistribute resource in S to N to even out availability of water

• began in 2003 (estimated to take 50yrs) + will cost $62b

• It involves 3 canals which run 1,300km across China + link countries 4 main rivers

• Attempting to transfer 44.8nm³ per day

Cost ben analysis of China’s N-S transfer project

 

	Benefits	Costs
Social	Improving water scarcity in economy viable places in N + people that live there (more drinking water)	Most people believe it is an unsustainable project Costs 48b dollars for short term relief
Economic	Designed to divert 44.8b cubic meters of water annual to N- save China from water crisis that could set back it’s dev by years	About 345,00 villages have been displaced so far + rural areas left out + water table in south dropping
Environmental		More than ½ Chinas 50,000 rivers vanished in past 2 decades Diversion Is creating scarcity in S poverty peripheral areas River pollution not fixed

Aral sea location + why it is a good case study

Once worlds 4th largest Inland Sea, transboundary between Kazakhstan + Uzbekistan

USE FOR:

• Example of water scarcity,

• water qual issues,

• social/health impacts of inadequate water + economic impacts,

• water costs increase

• water conflict/ transboundary water source

• Large scale hard management water scheme

How did water transfer project led to shrinking of Aral sea + water scarcity

• soviet union undertook major water diversion project on Aral sea region. The regions 2 major rivers (fed by snowmelt + precip) were used to irrigate farm for cotton + crops in desert area= major impact on world 4th largest sea

• As Aral dried up, fisheries + communities that depended on it collapsed + increasingly salty water became polluted with fertilisers + pesticides. And now exposed bedrock was blown onto fields and degraded the soil (humans actions leading to water scarcity)

• River diversion= less water to sea= shrinking sea= impact on evaporation= less rain= already arid= more arid

Benefits of the water transfer project (Aral sea)

Former soviet union

• diversion of water to irrigate land + allow for development of fruit + cotton farming has created millions of jobs in a once unproductive regions

Uzbekistan Gov

• Irrigation scheme allowed poor Uzbekistan country with few resources to remain one of worlds largest exporters of cotton + there is hope to discover oil deposits beneath the dry seabed

Cost of Aral sea water (social, environmental + economic)

Social	Environmental	Economic
-Local residents= health problems from dust + salt + drinking water= heavily polluted= forced water tankers= expensive -Kazakhstan farmers+ irrigation= crops= salty+ polluted May people lost jobs in farming+ forced to become environmental refugees	-Biodiversity dropped massively- about halved bird + mammal species + nearly no fish left -Water engineers- irrigation canals= built poorly= water can leak out + evaporate- main canal allows 30-75% of water to go to waste	-Fishing industry once employed over 60,000 people around sea has now collapsed + unemployment + economic hardship everywhere + shipping economy= collapsed

Little Aral restoration project

• 2017 Kazakhstan gov secured $126m loan from world bank to help save N part of sea

• Gov had used an earlier 70m loan to build a dam to split sea into 2

• Officials claim N sea is already refilling

• Has been effective in restarting fisheries + rain has returned

• However S Uzbekistan side= still shrinking + may be too late to save it

• Uzbekistan still need the water rom rivers for cotton to develop so river water isn’t reaching Aral

• Both Syr Darya (Kazak)+ Amu Darya (Uzbek) headwaters are controlled by other countries= conflict

What conflict has been created as result of Little Aral sea restoration project

• Conflict between Kazak + Uzbek, saving Little Aral has not helped save big Aral

• By building dam it has stopped the Uzbekistan side having chance to fill up

• Cross border water= always conflict

• Political decision- choice to grow cotton (water needy) plant in desert= need irrigation but 50% of water evaporated before irrigated + all cotton farms owned by gov so excessive water used at no cost= pollution of water with pesticide

• Aralsk= once key port town now= 50km from sea + water is transported from 150km away (scarcity) + 50,000 have migrated from town

Transboundary waters

aquifers, lakes, rivers shared by 2 or mor countries- supports the lives and livelihoods of vast nu of people across the world

• reduced transboundary water supplies= potential to cause conflict between + within countries

• UN-water have stated that dealing with this problem will require supranational, integrated approach to transboundary water resources management based on legal frameworks and shared benefits and costs.

River Nile info (transboundary water system)

6700km (worlds longest river)

2 main sources- Blue Nile (Ethiopian Highlands) + White Nile (further south in Lake Victoria)

White Nile= 30% of total discharge + Blue= shorter but provides majority of river’s flow

• Control of blue Nile= massive impact downstream = most power in Ethiopia (source)

River regime is highly seasonal, peak July-Sept (also influenced by El Nino + La Nina cycles (inter annual variations)

• So periods where water stress, scarcity= more likely (conflict= more likely)

River system flows through hot, arid areas including Sudd Swamp of South Sudan

• Significant amount of flow can be lost to evaporation before reaching the delta

Grand Ethiopian Renaissance Dam (GERD)

• been under construction since 2011 will be largest hydroelectric dam in Africa when finished

• The reservoir will take up to 15yrs to fill before reaching full electricity capacity

• It is trying to fuel industrialisation of Ethiopia

• Dispute it will decrease flow in Sudan + Egypt (Egypt= especially stressed as it could decrease flow into their Aswan Dam

Potential cost ben of GERD in Ethiopia, Sudan, Egypt

Water is used as political advantage= TENSION

	Likely Benefit	Likely costs
Ethiopia	-Will power Ethiopia + other countries industrialisation+ economic dev -70% of Ethiopia don’t have electricity dam will provide this (social dev) -Greater economic, political, strategic regional power Pop will double in next 30yrs= need GDP to double to keep up	-Didn’t ask other countries before starting build= threat of war -Thousands have been displaced already
Sudan	-Cheap electricity= faster dev -Regulate water levels, less floods (due to flatter regime) -Closer political alliance with Ethiopia -Access to electricity= potential to dev + use share of the Nile water= issue for Egypt	-water= highly politicized (not consulted before)= tension growing -reduced flow downstream if reservoir is filled to fast -dam might be used to exert power (need to maintain positive relationship with Ethiopia)
Egypt	-In theory shouldn’t be threatened at GERD= HEP dam only	-Livelihood of Egypt depends on river -Severe impact on flow to Egypt- 2% reduction inflow= loss of 200,000 hectares of land (famine?) -Power balance= changing

Restoration of River Kallang, Singapore (sustainable water management technique)

• 2012 restoration of 2.7km Kallang river- previously forced into concrete channel now opened up into a more naturally flowing channel which protects the city from floods and provides better recreational opportunities

• river’s banks are designed to be able to safely overflow in times of heavy rainfall

• River can now handle 40% more water than old canal.

why are sustainable management techniques less controversial than other techniques

• they aim to balance economic, social + environmental need by working with local people and develop soft engineering projects that work with natural processes to restore water supplies and often involve water conservation.

• water management issues can be broken down into 3 sections:

  • water supply regulation

  • water qual regulation

  • moderation of extreme events (flooding + drought)

Sustainable water management- soft engineering+ land management strategies

Reforestation +forest conservation

• increase interception= decrease in surface runoff= increase lag time= decrease flooding

Reconnecting rivers to floodplains

• sediment deposition increase= building up natural defences e.g. levees (reduce flooding)

Wetland conservation/restoration/construction

• increase soil stability from root systems

• increase bio diversity + ecology

• natural water store

Permeable pavements

• increase percolation= increased groundwater stores= replenish aquifers = increase lag time= decrease flooding

Riparian buffers (river banks)

• provide natural defences

• e.g. grass embankments of river Mersey

Urban green space

• reduce surface runoff + increase groundwater stores

• increase well being

Singapore’s water issue

pop=6m

receives abundant rainfall but their is limited land for collection + storage of rainfall + high evaporation rates (tropical climate) + lack of groundwater resources + no rivers + salt water encroachment (island) = water scarcity issues

SOLUTION: Singapore national water agency has invested in research + tech to diversify water supply- local water catchments (includes 17 reservoirs) , imported water, recycled water (NEWater) + desalinated water

How is water being sustainably managed in Singapore

	How does scheme work	Pros	Cons
Catchment areas/ reservoirs	-2/3 surface area partially protected so rainwater can be collected (protected drinking water catchment)	-Abundant ‘free’ water (not reliant on Malaysia)= increase water security -Educate offenders on pollution	-Limited amount of space -Pollution clean-up + enforcement= $ This strategy= too small to solve problem by itself
Desalination	-5 desalination plants creating 160m gallons per day	-Singapore is an island (seawater abundant) -Relatively wealthy country- can invest in the tech needed	-Energy intensive -Expensive
NEWater	-Wastewater is treated using microfiltration, reverse osmosis + ultraviolet light disinfection -Most NEWater used in industry or retuned to reservoirs because it isn’t purified for drinking	-Efficient use of wastewater -Significant contribution to supply	-Needs public trust + engagement
Conservation	-Campaign/ education program have reduced water consumption from 1651 pppd (2003)- 141 pppd (2019) -Gov no longer subsides water for poorer residents -One of most efficient nations in terms of water use- just 5% lost	-Water use maxed -Relatively cheap	Water= more expensive for poorest -Requires attitude change- people would need to minimise use where they can

What are Integrated Drainage Basin Managements

According to world bank IDMB aim to establish a framework for coordination whereby all administration and stakeholders involved in river basin planning and management come together to develop an agreed set of policies and strategies. The aim is achieve a balanced and mutually acceptable approach to land, water and natural resources management.

The spectrum of conflict + cooperation

analysis- most common event= mild verbal support/ agreement- this is protective as it doesn’t cause conflict by agreeing/disagreeing and it isn’t written so is less permeant

(more cooperation than conflict)

Water sharing treaties + framework (just be aware of vibe of them)

The Helsinki rules

• international guideline regulating hoe rivers and their connecting groundwaters that cross national boundaries may be used

• Treaties must include concepts such as equitable use + equitable shares

• + share should be based on factors such as: natural factors, social + economic needs, downstream impact, dependency, prior use, efficiency

The Berlin rule

• replace Helsinki rules + have 9 water management principles

• Participatory water management (involve public), coordinated use, integrated management, sustainability, minimisation of environ harm, cooperation over shared water resources, equitable utilisation of shred water sources, avoidance of transboundary harm, equitable participation

ANALYSIS:

• participatory water management= more democratic but 🕑 consuming

• Berlin rules=more dissolved decision making (involve public) + more focus on sustainability, focus on internal as well as international water management

• overall strength= objective framework provided

• Overall limitation- somewhat nebulous e.g. equitable use is debatable (too cloudy + basic