Responses to rising demands

Managing future water supplies will require action at a variety of levels, ranging from large-scale projects funded by governments down to changing consumers’ attitudes to water use at a local level. Likely actions include:
1. hard engineering projects to increase water storage and transfer, as for example in China’s Three Gorges Project and its South–North Transfer Project
2. restoration of lost, mainly rural, water supplies, for example in the Aral Sea ‘rescue’
3. water conservation in urban areas, involving such actions as rainwater harvesting and water recycling
The advantages and disadvantages of some of these actions have been discussed already.
As demands for water rise tension is likely to increase.
Major engineering projects will become too costly and their environmental impacts too great.
Privatisation of water supply and sanitation services, together with the use of new technology, will change the economics of water use.
People’s concerns and prior- ities will change over time, as will their views of costs and benefits.
There is the like- lihood that water insecurity and water poverty will fuel major conflicts.
The three gorges projected
1. China’s Three Gorges Project along the Yangtze River, the world’s largest hydroelectric scheme, is due to come fully on stream during 2009.
2. Given its current reliance on coal-fired power stations (70%), China sees hydroelectric power as clean energy with which to support its rapid industrial growth.
3. However, the social and environmental costs of using this source of energy are already apparent, well before the economic benefits are reaped.
4. Benefits
  1. The 18,000 MW of water-generated electricity could save 50 million tonnes of coal each year.
  2. The project will supply water to a region respon- sible for 22% of China’s GDP.
  3. Flood protection could save many lives and cut the financial losses created by flood damage.
  4. Navigational improvements could help open up the interior region of China to development.
5. Costs
  1. The dammed waters will drown 100,000 hectares of arable land, 13 cities, many smaller settlements and 1,500 factories.
  2. Some 1.9 million people will be displaced from their homes and lose their land.
  3. Dam failure, earthquakes, heavy rains and even terrorism pose serious safety risks.
  4. The ecological impacts on fisheries, biodiversity and habitats are considerable.
  5. Pollution will increase as abandoned mines and factories are flooded.
  6. Important archaeological and other heritage sites will be lost.
  7. The river has the world’s fifth largest sediment load. Sediment could damage turbines and become trapped behind the dam, raising water levels and reducing soil fertility downstream.
Hard engineering
1. Most major dam construction in the future is likely to be limited to developing countries.
2. Current global dam-building costs are between $22 and $31 billion each year.
3. Half the world’s large dams were built primarily for irrigation (contributing up to 16% of world food production).
4. Hydroelectric power, flood control and domestic water supply are other benefits.
5. Economic costs
  1. The construction of large dams seems to overrun projected costs by an average of 50%.
  2. Water sales rarely cover the costs of water supply in developing countries.
  3. Even in the long term, multi-purpose schemes often fail in financial terms.
  4. The total global investment in dams between 1950 and 2000 was estimated at around $146 billion.
6. Ecological costs
  1. Dams, inter-basin transfers and water withdrawals for irrigation have fragmented 6% of the world’s rivers, disrupting floodplain agriculture, fisheries, pasture, forestry and ecosystems.
  2. Many of these ecological impacts were not anticipated before the dams were built.
  3. Environmental impact assessments (EIAs) are relatively new.
7. Social costs
  1. During the construction phase local communities are starved of development and welfare investment.
  2. Communities and their livelihoods are severely disrupted.
  3. Construction of dams in India and China alone is reported to have displaced 58 million people in the last four decades.
River, lake and wetland restoration
1. A number of management strategies are being used to return water environments to their natural state.
2. At a local scale, this can involve restoring meanders, replanting vegetation and using sustainable methods to manage watercourses for people and the environment.
3. A good example is provided by the River Restoration Centre in the UK.
4. It began its work on the rivers Cole and Skerne and has since tackled similar projects throughout the UK
5. On a larger scale, the US Army Corps of Engineers has begun restoring the Kissimmee River in Florida.
6. When restoration is complete in 2011, more than 100 km2 of floodplain ecosystem will be restored, including 8,000 ha of wetlands and 75 km of river channel.
7. Restoration on an even grander scale is being planned in the Lower Danube basin, but perhaps the largest project currently being considered is the restoration of the Aral Sea.
Restoring the Aral Sea
1. Since the breaking up of the Soviet Union the northern part of the Aral Sea is in Kazakhstan and the southern part in Uzbekistan.
2. In 2007 the Kazakhstan government secured a $126 million loan from the World Bank to help save the northern part of the Aral Sea
3. It is an ambi- tious project aimed at reversing one of the world’s worst environmental disasters.
4. The Kazakhstan government used an earlier $68 million loan to build a dam that has split the sea into two parts
5. Officials claim that the northern sea is already filling up, now that water from the Syr Darya is once again flowing into the Aral.
6. The new loan will be used to build a second dam to bring the water back to the deserted port of Aralsk.
7. Communities in the area are already feeling the impact.
8. The fishermen are back in their boats, rain has returned and the future no longer looks hopeless.
9. However, the actions taken so far have not solved the problem on the Uzbek side of the border.
10. The southern part of the sea is still shrinking, and many fact experts believe it is too late to save it.
11. The waters if the Amu Darya, which should be feeding into the sea, are desperately needed for growing cotton
12. The economyy of Uzbekistan is heavily dependent on this cash crop
13. An additional problem with both this river and the Syr Darya is that their headwaters are controlled by other countries
14. Even worse is the fact that this is a part of the world where sensitive water developments could easily trigger conflict
15. For a more radical proposal to solve the Aral Sea problem using major diversions of the Volga and Ob rivers
Water conservation
1. Water conservation involves reducing the amount of water used (i.e. demand) rather than trying to increase water supplies. In a world where the supply is finite, this is an important strategy.
2. Water conservation can be applied in a variety of situations.
3. In agriculture, it can involve more efficient irrigation.
4. In industry, water can be treated or recycled for further use. Domestically, water savings and water harvesting are beginning to move from a DIY basis to a more commercial footing.
5. In some places, efforts are being made to conserve wetlands, as part of a wider challenge to store water and develop a more eco-hydrological view of water resources and their management.
6. At home, measures such as raising water prices and introducing water meters make consumers more careful about their consumption of water.
7. Effective use of water for food production is of crucial importance, and irrigation is a key area in this.
8. In the past, flood irrigation has proved to be wasteful of water as it leads to high evaporation and seepage losses.
9. Modern spray technology is more controllable, and the more advanced ‘drip’ irrigation, though expensive, is more effective.
10. Fertigation, which uses small quantities of fertiliser with fine water sprinklers, has proved to be effective in Israel and the USA.
11. Conservation of industrial and domestic water is about recycling and re-use.
12. Potable water is crucial for some purposes but grey water can be used for others.
13. Water can be treated using filters or chemicals, but sewage and polluted water require strict disposal strategies.
14. In and around the home, there is much that can be done to conserve water

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Responses to rising demands

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	Erstellt von Jodie Goodacre vor fast 11 Jahre