P9 Flashcards
1
Q
3.3 Approaches to managing water supplies
The use and subsequent abuse of water is one of the most controversial and complex issues facing the world.
Table 3.7 shows that there is a wide range of players involved in any issue relating to water resources.
Controversy 1: social versus political players
A
- Social players see access to clean, safe water as a human right, whereas political players see water as a human need which, like food, shelter and energy, can be provided in a number of ways through market mechanisms (private), public services (government) or public-private partnerships (via governments and NGOs).
- The infrastructure of water provision is extremely costly, so governments have to find a mechanism to pay for it in order to satisfy the needs of their people.
- It was estimated that meeting the UN’s MDGs of halving the proportion of the population without access to safe water supply and improved sanitation would cost over US$200 billion.
2
Q
Controversy 2: economic versus environmental players
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- In order to keep pace with rising demand, business players favour hard engineering schemes such as mega dams, water transfer projects and clusters of desalination plants.
- Inevitably, these schemes have very high social and environmental costs, and are opposed by social and environmental players, who favour more sustainable approaches.
- There are therefore a number of responses that can be made to manage future water supplies, with action at a variety of levels, ranging from large-scale projects funded by international governmental organisations (IGOs) such as the World Bank, and by governments, down to changing individual consumers’ attitudes to water use to encourage conservation at a local scale.
- The large projects usually employ top down approaches to ensure efficient delivery, which can disregard people’s wishes, whereas more localised projects, such as sustainable WaterAid projects, tend to be bottom up, involving local people in their management, but sometimes with scaling-up difficulties.
3
Q
Table 3.7 Players involved in issues relating to water resources
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4
Q
Hard-engineering projects
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In all cases, high levels of capital and technology are needed to carry out these projects. Economic costs are inevitably very high (multi-billion) and, while there are often economic benefits across a large area, questions hav to be asked about the environmental and social costs.
Water transfer schemes
Mega dams
Desalination
5
Q
Water transfer schemes
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- Water transfer schemes involve the diversion of water from one drainage basin to another (inter-basin transfer), either by diverting the river itself or by constructing a large canal to carry water from an area of surplus to an area of deficit.
- The controversy lies in large-scale, high-tech transfer schemes.
- The engineering itself and the actual water transfer schemes have been successful, but there are many environmental and social disadvantages.
- Additionally, continued use of transferred water may lead to long-term changes to local and regional hydrological conditions, perhaps increasing flood risk, damaging fish stocks, spreading diseases and pollution, and acting as a pathway for introducing alien species into new river environments.
6
Q
Table 3.8 Existing schemes and details
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7
Q
Mega dams
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- Nearly 60 per cent of the world’s major rivers are impeded by large dams.
- Rivers such as the Colorado have been impeded, stored, rechanneled and reengineered in a technological exercise to redesign natural flows for the benefit of humankind.
- In 2010 there were 845,000 dams in the world, of which some 5,000 could be considered to be mega dams.
- These mega dams have the facility to store fifteen per cent of the annual global run-off, which is theoretically a huge addition to the blue water component.
- However, evaporation losses are very high as many dams are located in semi-arid areas.
- In the 1980s, mega dams were seen as the panacea for the world’s water shortages and, through irrigation, for the food security issue - irrigated areas contribute up to sixteen per cent of world-food production.
- Many dams were large multipurpose schemes with multiple benefits, providing irrigation, HEP and flood control, as well as domestic water supply.
- Well-known examples include the dams along the Colorado, the Three Gorges Dam in China, and the Aswan High Dam.
8
Q
Recently, the mega dam is ‘back in fashion’, with many new and ever-bigger dams planned for developing countries. There are several reasons for this:
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- China is the world’s leading dam builder (46 per cent of the world’s total) and, as part of its FDI programme in Africa, is building many huge dams
- With rising global concerns about global warming from greenhouse gas emissions, there is a move to produce more clean energy from renewables.
- In developed countries, most of the most technologically attractive sites have been used, whereas along rivers such as the Congo (Africa) or the Panama Basin in South America, there are plentiful sites to construct dams, largely for HEP development to fuel economic growth.
9
Q
China’s South-North Transfer Project
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- The south of China is rich in water resources but the north is not.
- To redistribute these resources and to even out the availability of water, a gigantic south-north water diversion project was begun in 2003.
- It is expected to take 50 years to complete and will cost close to US$100 billion.
- The project involves building three canals that run 1300 km across the eastern, middle and western parts of China and link the country’s four major rivers: the Yangtze, Yellow, Huai and Hai (Figure 3.19).
- The scale of engineering involved in this scheme is awesome - It will transfer a total of 44.8 billion cubic metres of water per year.
- Central government will provide 60 per cent of the cost of the scheme, with the rest coming from local authorities, which, in turn, will charge domestic and industrial users.
- Water conservation, improved irrigation, pollution treatment and environmental protection are included in the plans.
- Critics are concerned about the uncertainties and risks associated with the project.
- These include the likelihood of significant ecological and environmental impacts along the waterways, resettlement issues and worsening water quality.
- The Yangtze River is already severely polluted, and the water of the Yellow River is undrinkable. Some experts fear an ecological disaster.
10
Q
Desalination
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- There has been a global boom in desalination, which draws from supplies from the ocean as opposed to from the one per cent of freshwater supplies available for use on Earth.
- It is, therefore, a sustainable process as it conserves supplies for future generations.
- Although people have been desalinating water for centuries, recent breakthroughs in technology (for example, the development of the reverse osmosis process) have made desalination far more cost effective (given that freshwater exploitation costs are rising), less energy intensive and easier to implement on a large scale.
- However, it is still a costly option and does have a major ecological impact on marine life. TNCs such as Veolia (France), Salini Impregilo (Italy), Doosan (South Korea) and GE (USA) are building desalination plants around the world.
- The top six nations by desalination capacity are (greatest first) Saudi Arabia, the USA, UAE, Spain, Kuwait and Japan (Figure 3.20).
- With the future advent of carbon nanotube membranes requiring less pressure and therefore greater energy efficiency, relative costs of desalination may decrease even further, making this option - in effect - the ultimate techno-fix.
- It is more viable than massive hard-engineering water transfers, but there are major concerns about its environmental impact.
- Left-over water returned from the desalination process has twice the salt concentration of sea water.
- Dumping it near the shoreline will have adverse consequences on coral reefs and their food webs (Figure 3.21).
- A number of US cities have outgrown or exhausted their local freshwater sources.
- To continue to deliver water to residents, their local governments have to pipe water in from further away or pump from greater depths.
- This infrastructure is expensive and has led to rising prices.
- The cost of desalinating water has come down by about 4 per cent each year.
- Improvements in technology mean that desalination is beginning to catch up with the increased cost of freshwater.
- Many of the countries involved are relatively well developed technologically and increasingly water stressed.
- The OPEC countries of Saudi Arabia, UAE, Kuwait and Libya have the additional advantage of cheap energy to distil fresh water from the oceans; however, this involves the use of fossil fuels.
- Currently, there are 14.000 desalination plants in the world, including one in the Thames Estuary.
- In conclusion, technological innovations and adaptations have a role to play in meeting the mounting threats to freshwater supplies that should not be overlooked; it should not be overstated either, as they cannot be regarded as fully sustainable.
11
Q
Defining sustainable water management
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Figure 3.22 uses the sustainability quadrant to focus on water management. Increasingly, the concept of water sustainability is enshrined and embedded in the notion of water security. For all the world’s nations, communities and peoples, clean, safe water should be available, accessible and affordable (the three As).
The figure will help you to consider what this actually means, and whether sustainable development, management and use can be achieved, to safeguard the resource for future generations.
12
Q
Environmental sustainability
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- a major issue.
- Many of the world’s rivers are ecologically threatened as a result of human actions, which have polluted and damaged water supplies.
- The water is of poor quality and acts as a vector for water-borne diseases.
- Nearly 25 per cent of the world’s peoples lack access to safe water, so environmental sustainability protects water quality.
13
Q
Economic sustainability
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- involves guaranteeing security of access to water for all groups at an affordable price.
- Interestingly, many schemes to manage rivers, such as mega dams, actually dispossess people of their land, homes and livelihoods.
- Privatised schemes to bring clean, safe water to millions often fail to deliver at affordable prices.
- Economic sustainability is also achieved by minimising wastage and maximising efficiency of usage, for example in irrigation.
14
Q
Socio-cultural sustainability
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manages water supplies in such a way that it takes into account the views of all users, including the poor and disadvantaged people, and leads to equitable distribution within and between countries.
15
Q
Water conservation
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- Conservation of water supplies is one of the main thrusts of the sustainable use of water as it manages demand.
- This can be done in a number of ways in the various economic sectors.
- As agriculture is the main user of water supplies (70 per cent), especially in semi-arid areas for irrigation, there are many ways that the use of water can be made more efficient.
- In agriculture the maxim has to be ‘more crop per drop’ where cash crops are grown. Sprinkler and surface flood irrigation systems are steadily being replaced by modern automated spray technology and more advanced drip irrigation systems, which use less water.
- Israel is a major pioneer of water conservation.
- There are also great savings to be made in repairing leaks in irrigation systems.
- For many farmers operating in areas of water scarcity, such as northern China or western USA, there is a pressing need to make water go further.
- Recycling of city waste water for agricultural use is a feasible, relatively low-cost option as this grey water does not need to be of drinking-water quality.
- This recycling happens regularly on the North China Plains.
- Empowering farming communities to make their own decisions concerning water use has also been successful.
- There are numerous intermediate-technology solutions to water conservation, such as the ‘magic stones’ system practised widely across the semi-arid Sahel (lines of stones 5-10 cm high are laid along the contours of a hill to prevent soil erosion and conserve soil moisture) or the development of devices to store and recycle rain in areas reliant on rains (for rain-fed agriculture).
- Rainwater harvesting experiments in Uzbekistan put farmers in control of the irrigation network and allowed them to decide how much water they needed, as opposed to giving them a fixed allocation.
- This cut consumption by 30 per cent.
Specialised NGOs such as Farm Africa and WaterAid have helped farming communities develop a whole range of strategies to combat climate change-induced water scarcity.
Farmers are trained in minimising tilling so that water is conserved in a layer of mulch on the field’s surface, which absorbs the rainwater and limits evaporation.
Agriculture advisers give guidance on types of crops that will generate good profits yet use less water, for example substituting dry crops such as ilives for thirsty citrops used to produce supposely olives for thirsty citrus fruits.
One current controversy
sustainable biofuels such as bioethanol and biodiesel (see page 58).
High technology also has a role to play.
Second-generation genetically-modified (GM) crops are being bred that are not only tolerant of diseases but also of drought and salty conditions - these include strains of maize, millet and wheat, which are vital food crops.
Agronomists are also beginning to devise tools to help monitor the efficiency of water use. Some have designed algorithms that use satellite data about surface temperatures to calculate the rate at which plants are absorbing and transpiring water - this means development agencies can concentrate their efforts for improvement on the most thirsty crops.
Systems have also been devised to grow crops using little water. Hydroponics involves growing crops in huge greenhouses that are carbon dioxide and temperature controlled. The crops are grown in shallow trays where they are drip-fed nutrients and water (there is no soil). The only issue is that while it may be a sustainable system water-wise for supplying food to arid lands, it is very energy intensive.
For businesses, water is not discretionary as without water, industry and the global economy falter. Water is an essential ingredient for many food and beverage products, such as beer and soft drinks. It is also used in a huge range of other industries such as making silicon chips and for cooling thermal power stations.
Rapid industrialisation, particularly in developing countries, has contaminated both rivers and aquifers, and for many industries it is not so much the quantity of the water but the quality of the water that is important.
Many large TNCs have reduced their consumption of water; for example, Coca-Cola bottling plants around the world committed to clean all their waste water by 2010 and then to recycle some of it for use as grey water in their plants for cleaning bottles and machinery. Coca-Cola is currently the largest beverage company in the world and has been the subject of adverse publicity over its intensive use of water (283 billion litres worldwide).
Many companies have improved their recycling of water as a response to legislation prohibiting the use of groundwater or due to rising costs in the price of water.
In Beijing, in water-stressed Northern China, zero liquid discharge rules ban companies from dumping waste water into the environment; this forces companies to recycle all their waste water by purifying it for reuse as grey water.
Conservation has also been very effective in reducing demand for domestic use. Here there is more of an attitudinal fix than a techno-fix, to persuade consumers to use less water.
Domestic water conservation includes reducing consumption by the installation of smart meters, which can monitor use and make higher charges in stress periods such as dry summers. Rain harvesting using a system of water butts is a further conservation measure in the garden. Strategies such as sharing a bath, putting a brick in the toilet cistern or using an eco-kettle can also cut down on consumption, often inspired by the threat of rising costs of metered water. In times of drought, water conservation can be enforced by hosepipe and sprinkler bans. The use of recycled water can be encouraged for flushing the toilet or for garden use such as watering plants with leftover washing-up water. Another development concerns the construction of climate-proofed gardens filled with drought-resistant species that can survive periods of water stress.
Filtration technology now means that there is very little dirty water that cannot physically be purified and recycled. Faced with the loss of cheap imports of water from Malaysia, Singapore has followed a path to water self-sufficiency - artificial rain catchments combined with treating sewage water. Water cleaned by a combination of dual membrane technology (microfiltration and reverse osmosis) and ultraviolet disinfection produces water that exceeds WHO quality thresholds. It is marketed as Newater and is now a key source of supply for the densely populated island (in 2010 some 30 per cent of Singapore’s drinking water was Newater). However, a psychological barrier has to be overcome on drinking water from toilets - another attitudinal fix.
Technology can be useful in a number of ways, such as water companies carrying out projects to cut down on leakage from broken pipes and burst water mains or treating and reusing industrial and waste water at their waterworks. The main strategies for reducing demands for water - recycling, grey water use and reducing consumption - can clearly make a major contribution to the sustainable management of water. Every little helps!
