Mismanagement of river basins watersheds and lakes

Mismanagement of river basins, watersheds and lakes • • Freshwater and the hydrological cycle Water “hot spots” in the world How to deal with water scarcity Global warming and water scarcity

Water “hot spots” http: //news. bbc. co. uk/2/shared/spl/hi/world/03/world_forum/water/html/mexico_city. stm

The Aral Sea in Central Asia was once the world's fourth biggest inland sea, and one of the world's most fertile regions. But economic mismanagement has turned the area into a toxic desert. The two rivers feeding the sea, the Amu Darya and the Syr Darya, were diverted in a Soviet scheme to grow cotton. Between 1962 and 1994, the level of the Aral Sea fell by 16 metres. The surrounding region now has one of the highest infant mortality rates in the world, and anaemia and cancers caused by chemicals blowing off the dried sea bed are common.

In a desperate attempt to keep their vessels in the shrinking Aral, channels were dredged to the open sea. it was a futile exercise, as the sea receded faster than the channels could be built. The fishing industry was effectively gone by 1982, and the canning plant processing frozen fish brought in from other areas to keep fishermen employed, folded in 1991. Of the region's 73 species of birds, 70 of mammals and 24 of fish, most have either perished or moved on.

Causes Lake Chad, once a huge lake straddling the borders of Chad, Nigeria and Cameroon, has shrunk by 95% since the mid 1960 s. The region's climate has changed during that time, with the monsoon rains which previously replenished the lake now greatly reduced. A recent study blamed human activities combined with local weather changes, not global warming. It said overgrazing had destroyed the savannah vegetation which itself influenced the weather patterns. As the climate has become drier, the demand for water to irrigate food crops has increased – quadrupling between 1983 and 1994 - depleting the lake further. Nine million farmers, fishermen, and herders in the region now face water shortages, crop failure, livestock deaths, collapsed fisheries, soil salinity and increasing poverty.

Mexico City is sinking because of the amount of water being pumped out from beneath its foundations. One of the largest and most populous cities in the world, it was once a lush land of lakes. But over the last 500 years the lakes have been drained and the surrounding forests chopped down. As the city grew in size, the water problem magnified. With no adequate drainage system, today rainwater mixes with sewage and is used for irrigation. The city is now at serious risk of running out of clean water. An estimated 40% of the city's water is lost through leaky pipes built at the turn of the century.

Mexico city (20 million people) In the last 100 years the city has sunken more than 9 meters. As a consequence the walls of the buildings are buckled. 23 steps have recently to be added to the independence monument (1900). 1 to 4 people have no access to water. 40% of water from aquifer is wasted due to inadequate piping system

River Nile A United Nations report has predicted that access to water may be the single biggest cause of conflict and war in Africa in the next 25 years. Experts have warned that if populations rise as expected in Egypt, Ethiopia and Sudan - the three countries most dependent on the Nile - competition for its waters will be intense. Cairo said in 1991 that it was ready to use force to protect its access to the 7, 000 kmlong river, which with its tributaries runs through nine countries. However, recent years have seen Egypt, Ethiopia and Sudan agree to use the river equitably and apply the principles of sustainable development.

Turkey Water-rich by Middle-Eastern standards, Turkey has in recent years undertaken an ambitious project to sell water from its Manavgat river across the region. It is still vulnerable to shortages, however - just a few weeks after Turkey agreed to sell water to Israel, officials were warning of a water crisis. Another project, a system of 22 dams on the Tigris and Euphrates rivers, has provoked criticism from downstream neighbours Iraq and Syria.

China's urban community suffers most from water scarcity. In 1990, about 26 percent of the total population lived in cities, increasing to 35 percent (or 450 million) 2000. Water scarcity also remains a serious threat to the nation's food self-sufficiency. About 70 percent of the grains produced in China are cultivated on irrigated land. Food security is expected to worsen with the expected population rise from 1. 2 billion to 1. 5 billion in 2030.

National water use in China Water consumption PRC: 550 billion m 3 (2000)

Panting schemes to reduce soil erosion (Mu Us desert northwestern of China)

South-to North water diversion project

Water scarcity • Freshwater and the hydrological cycle • Water “hot spots” in the world • How to deal with water scarcity – XXXX • Global warming and water scarcity

VALUING WATER • Dublin Statement on Water and Sustainable Development (1992): 'Principle No. 4: Water has an economic value in all its competing uses and should be recognized as an economic good. Within this principle, it is vital to recognize first the basic right of all human beings to have access to clean water and sanitation at an affordable price. Past failure to recognize the economic value of water has led to wasteful and environmentally damaging uses of the resource. Managing water as an economic good is an important way of achieving efficient and equitable use, and of encouraging conservation and protection of water resources. ‘ • Agenda 21, Chapter 18 (UNCED, 1992): 'Water should be regarded as a finite resource having an economic value with significant social and economic implications regarding the importance of meeting basic needs. ‘ • Ministerial Declaration of the 2 nd World Water Forum (The Hague, 2000): 'To manage water in a way that reflects its economic, social, environmental and cultural values for all its uses, and to move towards pricing water services to reflect the cost of their provision. This approach should take account of the need for equity and the basic needs of the poor and the vulnerable. ‘ • Ministerial Declaration of the 3 rd World Water Forum (Kyoto, 2003): 'Funds should be raised by adopting cost recovery approaches which suit local climatic, environmental and social conditions and the "polluter-pays" principle, with due consideration to the poor. All sources of financing, both public and private, national and international, must be mobilized and used in the most efficient and effective way. '

Water pricing in developed countries

When the supply systems are deficient, the poor are the first to suffer. Those who do not benefit from a house connection are often forced to obtain water from informal street vendors at a much higher price. The table below shows house connection prices versus informal vendor prices (in US$) in selected developing countries. City Cost of water for domestic use (a)(house connection: 10 m 3/month) in US$/m 3 Ratio (b/a) Price charged by informal vendors (b) in US$/m 3 Vientiane (Lao PDR) 0. 11 14. 68 135. 92 Male* (Maldives) 5. 70 14. 44 2. 53 Mandalay (Myanmar) 0. 81 11. 33 14. 00 Faisalabad (Pakistan) 0. 11 7. 38 68. 33 Bandung (Indonesia) 0. 12 6. 05 50. 00 Delhi* (India) 0. 01 4. 89 489. 00 Manila (Philippines) 0. 11 4. 74 42. 32 Cebu (Philippines) 0. 33 4. 17 12. 75 Davao* (Philippines) 0. 19 3. 79 19. 95 Chonburi* (Thailand) 0. 25 2. 43 9. 57 Phnom Penh (Cambodia) 0. 09 1. 64 18. 02 Bangkok* (Thailand) 0. 16 1. 62 10. 00 Ulaanbaatar (Mongolia) 0. 04 1. 51 35. 12 Hanoi (Viet Nam) 0. 11 1. 44 13. 33 Mumbai* (India) 0. 03 1. 12 40. 00 Ho Chi Minh City (Viet Nam) 0. 12 1. 08 9. 23

Ecosystems value The multiple roles of the aquatic ecosystems, called ecosystems services, present an economic value to water. Ecosystem type Total value per hectare (US$/year) Total global flow value (US$ billion/year) Tidal marsh/mangrove 6, 075 375 Swamps/floodplains 9, 990 1, 648 Lakes/rivers 19, 580 3, 231 Total 5, 254 Global and per hectare values of ecosystems have been calculated based on the estimation of the indirect values of the aquatic ecosystems in flood control, groundwater recharge, shoreline stabilization and shore protection, nutrition cycling and retentions, water purification, preservation of biodiversity, and recreation and tourism. [Source]: extracted from the World Water Development Report. Costanza et al. , 1997. 'The nature of the world's ecosystem services and natural capital' Nature, Vol. 387, pp. 253 -60.

Water scarcity • Freshwater and the hydrological cycle • Water “hot spots” in the world • How to deal with water scarcity – Water pricing/valuation – XXXX • Global warming and water scarcity

Water use efficiency in agriculture Drip irrigation reduces water use by 30 to 70 percent and increases crop yield by 20 to 90 percent compared with flooding methods These field are watered by furrow irrigation. Note the black gates that control the entry of water from the larger channel in front into the furrows. High-pressure irrigation of crops is more efficient than furrow irrigation, but not as efficient as low-pressure irrigation. Courtesy Dorchester County Cooperative Extension

Partial Root Drying technique PRD used in grape, lychee- and mangocultivations in Asia & Australia

Seawater Desalination System Membrane distillation uses a special membrane to bring out the water vapor generated from collected seawater, collecting it as freshwater, and it is a revolutionary new method different from its predecessors. This special membrane is a porous hydrophobic membrane, which means that water vapor can pass through it, but drops of water cannot. As shown in the diagram, by passing hot seawater through one side of the membrane, only the water vapor generated from the seawater passes through. The water vapor is then cooled by the cool water on the other side of the membrane, forming water drops, resulting in freshwater.

Reducing urban water consumption Can technology help? Simple devices like low-flow toilets can cut usage by 70 percent. When New York City was faced with spending $1 billion on a new pumping station in the early 1990 s, it opted instead to replace toilets. By 1997, after the city spent $295 million on incentives, 1. 33 million new toilets had been installed, saving 70 million to 90 million gallons per day. Overall, per capita consumption dropped from 195 gallons in 1991 to 169 gallons in 1999. ( 1 gallon = 4, 55 l).

Water scarcity • Freshwater and the hydrological cycle • Water “hot spots” in the world • How to deal with water scarcity – Water pricing/valuation – Water saving technologies • Water & Conflict ?

Water & Conflict • For assignment see Blackboard