Raffles Junior College
JC 1 Physical Geography
Catchment Management
Revision Pointers
Aral Sea

Arid zoneAral sea drying upships abandonedcoastline receding
Causes


Soviet schemeintended for the Aral to recede by diverting two rivers which fed Aral Sea.
By lowering Aral Sea’s level, it would boost the two other river’s potential for hydroelectric
power. River water was also removed to irrigate the desert to grow valuable crops such as
cotton.
Lots of water was taken from Aral for growing of cottonlimited success due to salty water.
Even more water was used up in effort to flush away salt in waterlogged soil.
Impacts



Fishing industry declinefishes all dead due to high salinity levels
Growth of salty desert/ Salt-filled soil is infertile
Social impact on local people
o
Health problems (one baby in ten dies before its first birthday)
o
Water supplies polluted by chemicals washed from cotton fields upstream
o
Salty dust attacks human throats and lungs
Responses

Minimise cotton growth as it requires lots of water

The 5 countries have pledged 1% GDP each to save the river

Build dam for water supply

Cut water supply to canal
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River Nile

Arid environment

10 riparian states with 300 million people (more than 40% of world’s population)
Causes

Cotton growing in Egypt and Sudanunder Britain’s control and pressure to expand growth

European “grab” of the area and parts of the Nile. Britain controlled Lake Victoria, source of
the Nile

Building of dams for HEP and irrigation purposes

High loss of water to evaporation

Emperor of Ethiopia agreement with Britain (lasts up till today)  not entitled to use the
water
Impact

Egypt dominates use of the Nile (more than 2/3 of water)

Aswan Dambenefits 60 million people

River delta has seen change in formation

Monuments are affected
Response

Talks for a more equitable share of water

Suggestion that Egypt should reduce or stop growing of cotton (too high a level of water
consumption)
River Jordan

200km long

Spans through several countries

Desert area

Politically/culturally and religiously complex area
Causes
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
Building of canals for large-scale irrigation of desert

Villages claim land for farmingincrease in demand for water

Massive farming to increase food supply

Rapid population growth due to migration

Underground water being tapped at an unsustainable rate esp. by Israel

Plants which water comes from are controlled by Israel.
Impacts

Israel has dominant control over usage and consumption of water

Resort to tapping of groundwater

Palestinian and Jordanian having limited access to waterneed to apply for to Israeli
authorities for permission to drill for water trapped in the reservoirs

Palestinians not allowed to build deep wells

River is shrinking
Response

Water conflicts and war?

Treaty for more equitable distribution of water (suggestion)
River Colorado

Arid desert

40 million people in 7 states

Naturally high salt content made more concentrated by high temp. and rocks in irrigation
areas
Causes

High usage (tourism and recreation)

River is regulated to the maximumprovides water that irrigates farms and vineyards

Ground water reserves are depleting at an alarming rate
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
Hoover Dam- Over regulates the river and builds up silt

Canals for farming and irrigation of crops in California

Wasteful methods of irrigation crop surplus, yet farmers are heavily subsidized for
irrigation

Evaporation (massive)

Urbanisation and population growthincreased demand and living standards
Impacts

Tap on groundwater/aquifer (drying outland subsides leaving salt on soil)

Conflicts (residents vs. visitors)

Conflict over right of water (farmers vs. Native tribal Americans)

Farming under threat
Response

Colorado Compactagreement between states to control river usage

California has laws controlling excessive use of water in droughts

Recycling of water
Three Gorges Dam

Yangtze is one of the world’s fastest and most dangerous riversmajor flood once every ten
years

1998 Great Floodone of the worst floodsdestroyed 1/10 of China’s grain
supplyenormous human costs, fighting and repairing damagethreatened to destabilize
China’s economy
Causes

Construction of dam to prevent flooding
Impacts

Protect 10 million people from flooding

High risk construction
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
Hydro Electric Powerinexpensive way of generating powergeneration of 18.2 million
kilowatts of electricitylargest power plant in the world supplying power needed by a city
four times the size of LAreduce China’s dependence on coal

Inundation behind dam

Volume of shipping expected to increase five-foldbetter for economy

Loss of shipping passageshipping elevator and system of locks

Loss of some cities/villages and its sense of community

Loss of crop growing areas with fertile soil for previously self-sufficient communities

Resettlement of communities in upstream areas (1.13 million), e.g. Fongdu, Fuling

Loss of traditional thought, ancient temples and beautiful landscape

Piling up of silt behind reservoir create huge flooding problem upstreamoccur more
frequently

May trigger off earthquake and landslides as the dam sits on a fault line

Destruction of historical artifacts and archaeological treasures including Zhang Fei temple

Species such as the Chinese river dolphin and Chinese paddlefish are near extinction
Response

Some strong village communities have chosen to build their new villagepulling together
government compensations so they can build the village they enjoy.
Management of river catchments creating conflicts of interests
Management Issues

Urbanization (Colorado River, Three Gorges Dam)

Vegetation Changes (Aral Sea, Three Gorges Dam, Colorado River)

Extraction from aquifers (River Jordan, Colorado River)

Water quality (Aral Sea)

Changes in river delta formation (River Nile)

Sedimentation/Silting of river (Three Gorges Dam)
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Conflict of Interests

Shared water resources (All except Three Gorges Dam)

Damming (Three Gorges Dam)

Control of water by upstream states (River Nile & Jordan River)

Pollution (Aral Sea)

Cultural issues (Three Gorges Dam, River Nile)
Responses to Conflict of Interests



Political
o
Treaties (Colorado River, possible for Jordan River, River Nile, Aral Sea)
o
Hydrowars (possibly for River Nile & Jordan River)
Economic
o
Economic Cooperation
o
Economic dominance
Environmental
o
Joint efforts to protect the environment (Aral Sea, River Nile)
o
Changes to freshwater technology (Colorado River)
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