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Fresh Water Historically limiting factor in arid regions 1940-1990 World population more than doubled 2.3 billion  5.3 billion Per capita water use doubled.

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Presentation on theme: "Fresh Water Historically limiting factor in arid regions 1940-1990 World population more than doubled 2.3 billion  5.3 billion Per capita water use doubled."— Presentation transcript:

1 Fresh Water Historically limiting factor in arid regions World population more than doubled 2.3 billion  5.3 billion Per capita water use doubled 400 m 3 person -1 year -1  800 m 3 person -1 year -1 Global water use increased fourfold 2000: USA ~2000 m 3 person -1 year -1 (~1450 gal day -1 ) A. A.Current Status In 1996, world human population using estimated 54% of all accessible fresh water in rivers, lakes, aquifers Many people predict disastrous consequences for world’s fresh water supply in coming years This potential disaster may have several causes

2 Fresh Water A. A.Current Status 1. 1.Distribution Uneven compared to population 75% of annual rainfall in areas containing less than one-third of global population Amazon River carries 20% of global runoff through area containing 10 million people Congo River carries 30% of Africa’s runoff through area containing 10% of population Uneven in space North America contains 19,000 m 3 per person per year vs m 3 per person per year in Asia 50% of annual runoff Uneven in time India gets 90% of annual rainfall during summer monsoon season (Jun-Sep); runs off too rapidly for efficient use

3 Fresh Water A. A.Current Status 2. 2.Usage patterns Agriculture – 69% Industry/Energy – 23% Domestic – 8% Varies among regions and with development Africa – 88% for agriculture (irrigation) Europe – >50% for industry Japan – Industrial but uses lots of water for growing rice Spain/Portugal – Arid; water used heavily for agriculture Personal use tracks standard of living Africa – 17 m 3 year -1 (47 l d -1 ) Asia – 31 m 3 year -1 (85 l d -1 ) UK – 122 m 3 year -1 (334 l d -1 ) US – 211 m 3 year -1 (578 l d -1 ) By 2020, water shortages likely in Ethiopia, India, Kenya, Nigeria, China (parts of China already face problems) Mexico City uses groundwater for 80% of municipal water supply Depletion exceeds aquifer recharge rate by 50-80% Sinking of land in some areas  Damage to buildings City imports water to meet demand

4 Fresh Water A. A.Current Status 3. 3.Contamination Numerous examples worldwide Biggest source = Agriculture Europe – Over 90% of rivers have elevated nutrient levels from agrochemicals Hungary – Nearly 40% of well fields contaminated Developing countries – On average, 90% to 95% of all domestic sewage and 75% of all industrial waste discharged into surface waters without treatment 4. 4.Impacts Nile River – Diverting water + retention of sediment behind dams has caused fertile delta to shrink Rhine River – Lost 8 of 44 fish species; 25 more endangered Lake Chad – Diversion + drought has caused shrinkage from 25,000 to 2,000 km 2 in 30 years LinkLink Aral Sea – Diversion for agriculture has caused severe shrinkage, with environmental & health problems L1 L2L1L2

5 Fresh Water B. B.Consequence – Conflicts World may have enough fresh water but uneven distribution  disputes, though few outright wars Middle East – Most acute water conflicts Jordan River Basin River originates in Lebanon Water shared by six nations (Wolf et al. 2005) Israel – 467 m 3 person -1 year -1 Jordan – 224 m 3 person -1 year -1

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7 Fresh Water B. B.Consequence – Conflicts Jordan River Basin 1951 Jordan announces plans to irrigate Jordan Valley by tapping Yarmuk R. (major tributary) Israel drains swamps between Israel & Syria Military clash between Israel & Syria 1953 Israel begins construction of National Water Carrier to transfer water from Jordan basin to Negev Desert for irrigation Syria responds with military action Israel changes intake to Sea of Galilee 1965 Palestinian National Liberation Front attacks diversion pumps operated by Israeli NWC 1960 Arab leaders agree on plan to divert headwater via Yarmuk R. to East Ghor (King Abdullah) Canal (Jordan) Syria announces plans to divert headwaters Military clash between Israel & Syria 1967 Israel destroys Arab diversion works on headwaters Series of events  Six-Day War 1969 Israel destroys canal built by Jordan


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