California River Supply
- Spatial imbalance: 75% of pptn falls in the North, 75% of population live in the South
- 65% of pptn is lost through evaporation and evapotranspiration
--> 13% of this flows out to sea
--> 22% is run off + human use
--> some remains in stores, however there are no aquifers
- Seasonal shortages: 50% pptn falls between November + March
- Cotton uses 50% agricultural water = 15% profit, cotton not an appropriate crop
- The amount of pptn in the catchment area is crucial
- Wetlands have been drained, natural habitats altered, depleted fish stocks to secure water supplies.
Wetlands reclamation and abstraction of water from the ground has affected the soil salinity.
- Overall, California uses 20% more water than it is allocated
Colorado River Basin
- Provides 60% of California's supply
- Since 1920's, series of treaties have been agreed between 7 US states with direct interest in the river and Mexico.
This has led to a "giant plumbing system" having come into being
- with 10+ major dams serving water needs of 30 million people.
- Due to management, flow has reduced --> Mexico receives very little
- 29 Dams inc. Hoover + several canals direct water to cities and Arizona
- 2/3 used for irrigation of 1.5million hectares of farmland
--> remainder used for urban, riparian vegetation/evaporated
- If shared, the activity upstream then affects water downstream
Colorado River Basin: Stakeholders
Farmers - Receive 80% of water allocation --> water wasted in flood irrigation + inappropriate crop choice.
City Dwellers - Cali. accused of using water other states may need in future (lack of sustainability?)
In 2007, Arizona took their full share --> Cali squeezed Imperail Valley Farmers.
+ Recreationalists - Conflict due to opposing views. Rec. development incg. concern for enviro. who would rather see less rec. activity in wet areas and wilderness. ie. Heavy tourist use of Lake Powell
Indigenous Groups - Natives along river have water claims (from treaties + agreements made between trives and fed.gvnt. in 1880's
Mexican People - 90% of water extracted before reaching Mexico --> Cucupa fishermen have had to move
US. Federal Gvnt. - Under pressure from own politicians to not change water allocations.
Plans to line canal carrying to Imperial Valley w/ concrete seems sensible; However g'water changes reduce Mexican supplies
--> may affect Mexican/US relations such as controlling immigration.
The size of France and Spain combined, it provides 75% of Australia's water. 85% of this is used for irrigation and 40% of farm produce.
- Great Artisan Basin + Murray Groundwater Basin - extraction in increasing by 4% every year
- 480mm average pptn - varies
- El Nino --> droughts + variability in rainfall, changing runoff patterns
- Diversions from Snowy Mountains + Glenelg River
- Salinity levels are increasing along Murray River due to irrigation and drought
--> this is causing farmers to lose produce + the destruction of natural habitats.
- Salt rich water is damaging roads, bridges, foundations and pipes in cities of Wagga Wagga + Shepperton through corrosion
Murray-Darling Basin Costs
- This is occurring due to polluted run off from farmers (in stagnant and slow-moving water)
- Farmers extract more than 4% per year, this is reducing amount of water.
- Irrigation is raising the water table --> waterlogging, decreased oxygen levels and drowning of plants
- Overcropping decreasing structure + fertility of soil
- Acidification occurring due to overfarming --> infertile soils
- Wind + water erosion due to vegetation clearance
Murray-Darling Basin Costs
- vegetation, wildlife habitats, Barmah-Milleus Forest cleared for farmland (this is similar to what has happened in China)
- Agriculture has reallocated large amounts of water (see effects below)
- Natural Heritage Sits, Macquarie Marshes + Narran Lake are all being lost due to over-extraction of water
- Removal of indigenous Aboriginal population as farmers claim more land
- A loss of tourist sites as land is converted for cereal production
Due to regulations of river flow:
- natural floodplains no longer flood
- red gum trees are dying out
- 50-80% of native wetlands birds and fish species have become extinct
Murray-Darling Basin - Stakeholders
- Agriculture - biggest stake + demand increasing - worth A$13.6 b. in 2007
- Industry - manufacturing, mining
- Aquaculture, fishing
- Residents - urban
- Local + Regional Governments
- Environmental Groups
- International Heritage + Conservation Agencies
Where can water conflicts occur? 1
- Supplies come from two main sources, River Jordan + 3 aquifers
- Low rainfall + an increasing population = conflict
- East - Turkey intend to build a dam from Tigris/Euphrates Rivers. Syria and Iraq oppose this due to the reduced water supplies, which would then threaten both economic development + food production
- West - Israelis/Syrians/Jordanians/Lebanese/Palestinians
- water is a tributary cause to the Arab-Israeli conflict (war -1967)
India and Bangladesh
- The majority of the Ganges (2.5km) is in India; the last section is in Bangladesh where it is called the Padma River.
- Ganges - UN Climate Report '07 --> glaciers that feed it may disappear by 2030; rivers flow would become seasonal, fed by monsoon (summer) pptn
- 1974 - India opened Farakka Barrage, 11km from Bangladeshi border.
--> dams divert water into irrigation systems + supply Indian domestic and industry needs
--> this then means Bangladesh suffers water shortages + polluted water.
- 1990 - agreement signed to share water - India had most control which meant Bangladesh had reduced flow, decreasing fish stocks + industry, increasing salinisation, erosion of delta and seawater incursion
Where can conflicts occur? 2
Nile Basin - Egypt and Ethiopia
- The Nile flows through 10 African countries
- Egypt - has most control and has historical right to the water
- Ethiopia - closest part is the Blue Nile; this could supply most of the country but cannot due to Egypt's control. Basins underneath provide the Nile with 86% of its water, yet also cannot be utilised as Egypt uses to prevent poverty. Ethiopia lacks money to be able to exploit it, whereas Egypt is fairly rich hence more powerful
- Jordan - 70-90% of water used for human purposes; the flow has reduced so much that the Dead Sea is now shrinking
Canada vs. Ethiopia
Problems in Canada include rising water bills + leakages; each person uses 800l per day to 'wash, cook + flush'.
In Ethiopia, consumption is only 1l a day, resulting in pollution and high risk of disease