Globale og regionale perspektiver for tilgjengelighet, behov og utnytting av vannressurser eller

1. Globale og regionale perspektiver for tilgjengelighet, behov og utnytting av vannressurser eller ”Global and regional perspectives on availability, demand and exploitation of water resources” Professor Ånund Killingtveit Institutt for vassbygging Fakultet for bygg- og miljøteknikk NTNU

2. Main topics in the presentation • Water - the global perspective • Available water resources • Trends in water consumption • Regional perspectives on water scarcity • About ”sustainable” water use • The need for Water Balance Policy • Three examples of non-sustainable water use • Summary and conclusions Professor Ånund Killingtveit

3. World water resources – water in stock A number of attempts have been made to assess the global water balance, here the figures published by World Resources Institute (WRI, 1988) are used The Global perspective Professor Ånund Killingtveit

4. Flows of the global water cycle (km3/yr) (data from Shiklomanov (1992) & WRI (1998)) The Global perspective Professor Ånund Killingtveit

5. Flows of the global water cycle (km3/yr) (data from Shiklomanov (1992) & WRI (1998)) The Global perspective Professor Ånund Killingtveit

6. Useful flows of the global water cycle (km3/yr) (data from Shiklomanov (1992) & WRI (1998)) The Global perspective Professor Ånund Killingtveit

7. The uneven distribution – the main problem • The average water availability figures gives a misleading picture • Water is determined by global and regional precipitation distribution • and therefore the water resources vary widely: • Spatially (from rainforests to deserts) • Temporally (seasonally and between years) The Global perspective Professor Ånund Killingtveit

8. Global runoff distribution, specific runoff The Global perspective Professor Ånund Killingtveit

9. Global runoff distribution, total volume The Global perspective Professor Ånund Killingtveit

10. Global runoff distribution, pr. capita The Global perspective Professor Ånund Killingtveit

11. Water use – main categories • Agriculture (Irrigation) • Reservoirs (Evaporation losses) • Municipal water supply (drinking water) • Industry (Process water) • Resipient of waste (wastewater, thermal pollution) • Energy (Hydropower, cooling water) • Aquaculture (Fish farming) • Environmental value (Wetlands, rivers, lakes) The Global perspective Professor Ånund Killingtveit

12. Global water use characteristics Professor Ånund Killingtveit

13. Global water use characteristics cont. Professor Ånund Killingtveit

14. Global water consumption - total volume The Global perspective Professor Ånund Killingtveit

15. Global water consumption - % of runoff The Global perspective Professor Ånund Killingtveit

16. How much fresh water is available in a country/region (for example in Egypt)? • Precipitation • +River inflow • + Regional water import • + Groundwater inflow • Evaporation • River outflow • - Regional water export • - Groundwater outflow • = Total available m3/year • The total available volume of water is usually limited • and determined by climate and geology. Some of it may be put to use but rarely utilized 100%, with advanced technology and management  40-50% • NB: Groundwater can be a source of water • but it must be included in the balance! Professor Ånund Killingtveit

17. How much water can we actually use? • Water use is usually limited by two main ”problems” as seen from the user point of view: • The water is not where we want to use it (”spatial” variation) • The water is not there when we need it (temporal variation) • The ”spatial problem” occurs when major consumption sites, for example large cities, are located in dry areas, while most of the rainfall occurs in unhibited mountainous areas • The temporal problem occur because rainfall and runoff tend to have large seasonal variations with long dry seasons and short High flow (flood) seasons, while consumption is fairly constant. In addition long term variation occur, for example of El Nino type or on longer timescales (Sahel, Lake Malawi, Zambezi etc) Professor Ånund Killingtveit

18. Example 1: Spatial variability ? The water is not where we want to use it (”spatial” variation) In Pangani river (below) precipitation is mainly occurring on the slopes of Mt Kilimanjaro, Mt Meru, Pare Mountains and the Ushambara. Here precipitation exceeds 2000 mm/yr, while in most of the catchment the area is dry (< 500 mm/yr) Professor Ånund Killingtveit

19. Example 2: Seasonal variability ? The water is not there when we want to use it (”temporal” variation). In Pangani river (below) precipitation is mainly occurring during 3-4 months (Feb-May). If water is not stored most of the runoff occur in the same periode, as seen from graphs below. Professor Ånund Killingtveit

20. Solutions to seasonal/long term variability ? The water is not there when we want to use it (”temporal” variation). The solution to this problem is to build dams. Dams are expensive, often with possible environmental effects, and usually controversial. There are, however few substitutes if a stable water supply is needed, for example for irrigation, municipal water supply or hydropower Storage of snow-melt flow Professor Ånund Killingtveit Storage of rainy season flow

21. Solutions to spatial variability ? The water is not where we want to use it (”spatial” variation). The solution to this problem is to build water transfer systems, canals, tunnels, diverting rivers etc. These systems are expensive, often with possible environmental effects, and usually controversial. There are, however few substitutes if a stable water supply is needed, for example for irrigation, municipal water supply or hydropower. Large regional irrigation canal Small irrigation canal Professor Ånund Killingtveit

22. How much water can we use? Water consumption is usually fairly evenly distributed Water avaliability typically varies strongly seasonal Need for storage – but not all water can be stored because reservoirs suffer from evaporation losses Professor Ånund Killingtveit

23. How much water do we need? • Water demand depends on: • Climate • Degree of industrial development • Agriculture (Irrigation) • Water technology for storage, transport and use Typical ”basic” demand is a minimum of 100 l pr. person and day, or approx. 40 m3/yr In reality a minimum of 500 m3/yr may be necessary in dry climate, with irrication the average increases. Water stress occur when average < 1700 m3/yr Water shortage when average < 1000 m3/yr Professor Ånund Killingtveit

24. Analysis of water demand vs. water availability Water need per capita (m3 per person per year)  (log scale) 100% 20% 10% Increasing mobilization of Water resources demands better Technology and management Minimum water need Limited management problems Large management problems Regional management needed Water availability per capita (m3 per person per year)  (log scale) Professor Ånund Killingtveit

25. Analysis of water demand vs. water availability Water need per capita (m3 per person per year)  (log scale) 100% 20% 10% Professor Ånund Killingtveit Water availability per capita (m3 per person per year)  (log scale)

26. Macroscale comparison of water availability vs. water demand (From Falkenmark) 100% Water need per capita (m3 per person per year)  (log scale) 20% 5% Increasing demand but fixed resources Professor Ånund Killingtveit Water availability per capita (m3 per person per year)  (log scale)

27. Water resources are fixed – population increases The Global perspective Professor Ånund Killingtveit

28. The Global perspective Professor Ånund Killingtveit

29. Regional overview Professor Ånund Killingtveit

30. Regional characteristics - Africa Sum for Africa: 4570 km3/year Professor Ånund Killingtveit

31. Regional characteristics - Africa Average for Africa: 6500 m3/capita/year Professor Ånund Killingtveit

32. Regional characteristics - Africa Professor Ånund Killingtveit

33. Regional characteristics - Africa Available water, 1000 m3/capita/year Average for Africa: 6500 m3/capita/year Professor Ånund Killingtveit

34. Regional characteristics - Africa Professor Ånund Killingtveit

35. Regional characteristics - Europa Water resources at yr. 2000 (m3/capita/year) Average for Europe: 4700 m3/capita/year (Norway: 96 000 m3/capita/year) Professor Ånund Killingtveit

36. Regional characteristics – East Asia Water resources at yr. 2000 (m3/capita/year) Professor Ånund Killingtveit

37. Regional characteristics – West Asia Water resources at yr. 2000 (m3/capita/year) Professor Ånund Killingtveit

38. Water use characteristics Professor Ånund Killingtveit

39. Sustainable water use Renewable water resources Some important steps: UN Water conference in Mar del Plata (1977) The Brundtland report (1987) Dublin principles, Water and Environment(1992) Rio-conference, Agenda 21 (1992) World Water Vision (2000) Professor Ånund Killingtveit

40. Sustainable water use • Sustainable development has been defined as "development that meets the needs and aspirations of the present without compromising the ability of future generations to meet their own needs" (Brundtland 1987) • Implicit in the desire for sustainability is the moral conviction that the current generation should pass on its inheritance of natural wealth, not unchanged, but undiminished in potential to support future generations. • A sustainable development should consider a time span of many generations. • Also, natural hydrological variations within this time span should be considered Professor Ånund Killingtveit

41. Renewable and Non-renewable resources • Renewable resources tend to be flow-limited and are reconstituted after human consumption or dispersion through natural processes driven by solar energy (which may be enhanced by human investment, as when trees are planted). • Example: River flow, shallow groundwater, biomass • Nonrenewable resources are generally stocklimited and have either very low or no renewal rates and prohibitive reconstitution costs • Example: Fossil groundwater aquifers, Topsoil, Tropical Rainforests, Oil, Natural gas Professor Ånund Killingtveit

42. Renewable and Non-renewable resources • Groundwater resourceshaveoften very low renewal rates and its sustainable use should be limited to its infiltration rate (renewable rate) • In many countries groundwater is used as if it was renewable, while in reality the groundwater is fossil, the aquifer was filled hundreds or thousands years ago • Examples: Libya, Saudi-Arabia, USA, Australia, India, China, ... Professor Ånund Killingtveit

43. Other water-related problems • Floods • Droughts Professor Ånund Killingtveit

44. Other water-related problems • Floods account for 1/3 of natural catastrophes • And more than 50% of lives lost • Flood losses in 90’s was 10 times losses in 60’s • An average of 66 Million people suffered flood damage annually in the years from 1973-1997 • Reasons for increased flooding problems are many: • Population trends in exposed regions • Increase in exposed values • Construction on flood-prone areas • Failure of flood protection works • Changes in environment conditions (e.g. Deforestation, Filling of wetlands, Urbanization) • Climate changes (?) Floods Professor Ånund Killingtveit

45. Other water-related problems • Increased water abstraction from rivers • Changes in land use (deforestation) • Long term climatic variability (Sahel, Ethiopia, ..) • Climate change (?) • Some examples: • Amu Darya and Syr Darya in Central Asia are drying up due to increased water use • The Yellow river in China did not reach the sea for 7 months in 1997 vs. A few days in 1972 • The Colorado River in US is drying up • England had a disastrous drought in the 1980’s • Disasters in Ethiopia and Eritrea • ... Droughts Professor Ånund Killingtveit

46. Non-Sustainable water use – Some examples • The Aral Sea disaster • The Ogallala Aquifer in USA • Saudi Arabia ground water irrigation system •  All examples related to overexploation of resources (non-sustainable use of limited water resources) Professor Ånund Killingtveit

47. Non-Sustainable water use – Some examples The Aral Sea Professor Ånund Killingtveit

48. Non-Sustainable water use – The Aral Sea • 1960: • Annual catch 50000 tons • 60000 employed in fishing industry • Aral sea 4th largest in the world • 2000: • Annual catch 0 tons • No commercial fishery • Area reduced by 75% Professor Ånund Killingtveit

49. Non-Sustainable water use – The Aral Sea Most of the changes have occurred within a time span when remote sensing was operational ... 1976 1997 Professor Ånund Killingtveit

50. Non-Sustainable water use – The Aral Sea • Water has been removed from the Aral Basin by the diversionof water from the Amu Darya River (which feeds the Aral Sea.) • Water from the Amu Darya is diverted into the Karakum Canal in Turkmenistan, near Afghanistan. The Karakum Canal, at 1400 km (850 miles), is the world's longest canal. • Water is used for irrigation in the formery dry desert areas where in particular cotton production is important • The destruction of the Aral Sea is the consequence of bringing desert soils into agricultural production Professor Ånund Killingtveit