Workshop on „Transboundary Watermanagement“ 14 - 24 July Berlin - Wednesday, 16. 07. 2003
Dr. H. Kehl Ecosystem Analysis and Integrated Ground Water Management 1 Todays Topic of Conversation and Discussion: ”Conflicts Between Modern and Traditional Irrigation Methods as a Result of Population Growth and misspended investments in Arid Areas". Internationale Weiterbildung und Entwicklung Gmb. H
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 2 As we all know: “Irrigation is essential for food production. . . especially in semi-arid and arid zones with above average population growth. ” FAO Internationale Weiterbildung und Entwicklung Gmb. H
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 3 At present one-sixth of the agricultural land in the world is irrigated and provides more than one-third of global food production. source: FAO Internationale Weiterbildung und Entwicklung Gmb. H
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 4 The food requirements of an ever-increasing world population higher necessitate agricultural production, a large share of which comes from irrigated lands, especially true in arid zones. Internationale Weiterbildung und Entwicklung Gmb. H
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 5 At approximately 80 to 87% of all the available freshwater supply is used for agriculture and food production. ” Therefore, only 13 to 20% is available for domestic and industrial requirements. source: FAO Internationale Weiterbildung und Entwicklung Gmb. H
Dr. H. Kehl Ecosystem Analysis and Integrated Ground Water Management The efficiency of 6 water in agricultural production is, however, low. Only 40 to 60% of the water is effectively used by crop, the remainder of the water is lost in the system, in the farm or on the field, either through evaporation, through runoff to the drainage system, or by percolation into the groundwater. source: FAO, UN-WWDR 2003 Internationale Weiterbildung und Entwicklung Gmb. H
Dr. H. Kehl Ecosystem Analysis and Integrated Ground Water Management What does it mean: efficiency? 7 In general, the term is used to quantify the relative output obtainable from a given input (e. g. investment or water). The Term „on-farm application efficiency“ or „field application efficiency“ generally refers to the fraction of the water volume applied to a farm or a field that is „consumed“ by a crop, relative to the amount applied. „In actual practice, however, the water reported to be „consumed“ in the field consists of actual EVAPOTRANSPIRATION [incl. Interception - but without percolation!]. “ The Term „Crop Water Use Efficiency“ (WUE) is a physiological index and should be used. The relevant measure is the response of crop to irrigation as total biomass produced (above-ground dry matter!) per unit mass of water taken. Internationale Weiterbildung und Entwicklung Gmb. H
Dr. H. Kehl Ecosystem Analysis and Integrated Ground Water Management What does it mean: efficiency? There is much evidence that, in a given climate, the growth of many crops is directly related to the amount of water they transpire, AND to the ratio of biomass below and above surface. Therefore, deep rooting crops will have a lower WUE. source: FAO, UN-WWDR 2003 Internationale Weiterbildung und Entwicklung Gmb. H 8
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 9 Poor management of irrigation water is one of the principal reasons for this low water use efficiency in irrigation. A range of environmental problems are linked to ineffective water use, such as waterlogging, leaching of agro-chemicals and consequent ground water pollution, as well as soil and ground water salinization resulting from inappropriate applications. Internationale Weiterbildung und Entwicklung Gmb. H
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 10 Studies on the economies of Sub-Saharan Africa (SSA) have generally neglected the link between economic growth and environmental quality. Internationale Weiterbildung und Entwicklung Gmb. H
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 11 The key to SSA future is to achieve long-term sustainable growth and not to implement and focus on showcase “white elephant” type expensive technologies (e. g. high-tech irrigation systems) developed under differing climatic, socio-economic conditions of HDCs (Highly Developed Countries). Frequently, that was a costly fallacy! Internationale Weiterbildung und Entwicklung Gmb. H
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 12 The quite recently launched Human Development Report (HDR-UNDP, July 8 th 2003) emphasized in particular the self-responsibility and self-determination of LDCs, especially their farmers with their knowledge of adapted irrigation systems as a key issue for successful developments in the future. Internationale Weiterbildung und Entwicklung Gmb. H
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 13 Complementary assistance comes from the FAO: „Key decision makers have tended to favour high-visibility projects with impressive works [ e. g. large Dam Projects, large-scale Center-Pivot sprinkler systems, large group well constructions for ground water utilization ], Internationale Weiterbildung und Entwicklung Gmb. H
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 14 while neglecting the more modest needs of indigenous farm units, as well as the issues of reconstruction of traditional irrigation systems, of modification, of training and maintenance that are of interest to lower-lever personel without decision-making power. “ Internationale Weiterbildung und Entwicklung Gmb. H
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 15 Lessons learned from several Case Studies, UNDP-, UN-WWD- and FAO Reports and keys to success Essential Elements to move towards integrated water resources management relate to: Institutional change, Comprehensive, radical reform of irrigation managment, e. g. turnover to Water User Associations, Integrated, ecologically prooved basin-wide approach, The knowledge base and knowledge transfer, Education, communication and participation, Self-responsibility and self-determination of farmers. Internationale Weiterbildung und Entwicklung Gmb. H
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 15 a Lessons learned from several Case Studies, UNDP-, UN-WWD- and FAO Reports and keys to success Essential Elements to move towards integrated water resources management relate to: Because of population growth in SSA the traditional rain-fed agriculture can not longer feed the people. The likewise traditional Water Harvesting System is three times more effective than rain-fed agriculture. Water Harvesting holds an intermittent status between rain-fed and irrigated agriculture (in respect of Production Costs, Cash Crops / Cash Income, Crop Yields, Salinity Hazard, Reliability of Water Supply). Internationale Weiterbildung und Entwicklung Gmb. H
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 15 b You wish to know something more about advanced techniques of Rain Water Harvesting for Crop Production? Please, visit the FAO Training Course in the Internet! The most complete and detailed „How-To Manual“ available. Strongly recommended ! URL: http: //www. fao. org/ag/aglw/wharv/whtoc/sld 001. htm Internationale Weiterbildung und Entwicklung Gmb. H
Dr. H. Kehl Ecosystem Analysis and Integrated Ground Water Management Modern vs. Traditional Water Harvesting and Irrigation Methods Ground water for irrigation in the desert Water harvesting system with catchment area 16 Bambo drip-Irrigation system in West Sumatra Internationale Weiterbildung und Entwicklung Gmb. H
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 17 Traditional Irrigation and Water Harvesting in Arid Areas Only a selection: : Rain water harvesting with micro/macro catchment areas and flood water harvesting (since thousands of years) Group construction of a sub-surface water harvesting tank in Zimbabwe. source: Dabane Trust Water Workshop Internationale Weiterbildung und Entwicklung Gmb. H
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 18 Traditional Irrigation and Water Harvesting in Arid Areas Only a selection: : Hand-dug wells (e. g. Qanats and horizontal wells, since thousands of years) Horizontal Tunnel Internationale Weiterbildung und Entwicklung Gmb. H
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 19 Traditional Irrigation and Water Harvesting in Arid Areas Only a selection: : Runoff Collection + This below surface building could be in Italy, Libya, Palestine, Turkey, etc. Cisterns (Near East, North Africa, since thousands of years) Greece & Roman Cisterns around the Mediterranean. typical for flat country or in mountains Indian Cistern Actually, thousands of Cisterns of different types are ruined and, therefore un-used. Internationale Weiterbildung und Entwicklung Gmb. H
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 20 Traditional Irrigation and Water Harvesting in Arid Areas Only a selection: : Roof Top Rain Water Harvesting (Near East, North Africa, India, etc. since thousands of years) source: cgwaindia Internationale Weiterbildung und Entwicklung Gmb. H
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 21 Traditional Irrigation and Water Harvesting in Semi-Arid Areas Only a selection: : Runoff agriculture (involves rain water harvesting, since thousands of years) source: www - WDDA / Israel Internationale Weiterbildung und Entwicklung Gmb. H
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 22 Traditional Irrigation and Water Harvesting in Arid Areas : Runoff Collection (e. g. also Only a selection: good to built up artificial ground water bodies, SMedit. area). runoff collection infiltration source (mod. ): www - Wag. Univ. Env. Sci. Runoff water harvesting during the rainy season to bypass the dry season. The deeper the soil the better it is suited as cropping area. Internationale Weiterbildung und Entwicklung Gmb. H
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 23 Traditional Irrigation and Water Harvesting in Arid Areas Only a selection: : Canal irrigation (e. g. Iraq, since thousands of years) Internationale Weiterbildung und Entwicklung Gmb. H
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 23 a Traditional Irrigation and Water Harvesting in Semi-Arid Areas : Canal irrigation with Only a selection: It was first used to pump water out of ships and was later used in irrigation. Archimedes‘ Screw (e. g. Iraq, Egypt, since thousands of years) (287 - 212 BD) Internationale Weiterbildung und Entwicklung Gmb. H
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 24 Traditional Irrigation and Water Harvesting in Arid Areas : Pits and open wells (e. g. Only a selection: Open well in Tanzania with unclean and unsanitary water. India, Central Africa, since thousands of years) Open well in Zambia proving water for cattle in the dry season. source: iirr. org Artificial pits / India source: ROPE/UK Internationale Weiterbildung und Entwicklung Gmb. H
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 24 Traditional Irrigation and Water Harvesting in Arid Areas Only a selection: : „ZAY“ pitting holes (since thousands of years) source: FAO copied witout permision! Internationale Weiterbildung und Entwicklung Gmb. H
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 25 Traditional Irrigation and Water Harvesting in Arid Areas Only a selection: : Porous clay jars (Near East, North Africa, India, etc. since thousands of years) Internationale Weiterbildung und Entwicklung Gmb. H
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 26 Traditional Irrigation and Water Harvesting in Wed Areas Only a selection: : Furrow irrigation (SE-Asia, Irian Jaya (Indonesia) and Papua New Guinea) Central Africa, India, etc. since thousands of years) The entire root zone is wetted to near-saturation (source: FAO) Photos: Kehl 1989 Internationale Weiterbildung und Entwicklung Gmb. H
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 27 Traditional Irrigation and Water Harvesting in Semi-Arid Areas : Flood and basin irrigation Only a selection: Central Madagacar (near Antanarivo) (SE-Asia, Central Africa, India, etc. since thousands of years) Flood and basin irrigation wets the entire root zone to saturation (source: FAO) photo: Kehl 2002 Internationale Weiterbildung und Entwicklung Gmb. H
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 28 Traditional Irrigation and Water Harvesting - Flood Water Only a selection: Pakistan (Ganges Delta) : Flood water harvesting (SE -Asia, Egypt in ancient time, India, etc. since thousands of years) Flood irrigation wets the entire root zone to saturation (source: FAO) source: Global Change GEO Internationale Weiterbildung und Entwicklung Gmb. H
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 29 Traditional Irrigation and Water Harvesting in Wet Areas Only a selection: : Drip irrigation with bamboo pipes (SE-Asia, India, etc. since thousands of years) Drip irrigation wets precisely the root zone to saturation (source: CSE-India) Internationale Weiterbildung und Entwicklung Gmb. H
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 30 Modern Irrigation Methods in Semi-Arid and Semi-Arid Zones Only a selection: : Fog catcher (for harvesting dew - Chile, Ecuador - at present experiments) Ecuador - high mountains The dark sheets suspended in the path of the moving cloud condense it. Internationale Weiterbildung und Entwicklung Gmb. H
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 31 Modern Irrigation Methods in Semi-Arid and Arid Zones Only a selection: Center Pivot System Technical very ambitious! Water Use Efficiency (WUE) of high pressure systems about 65 to 75%, depending on air humidity and wind. : Sprinkler irrigation (e. g. portable, solid, travelling sprinklers, center pivot systems - high pressure / low pressure, etc. utilizing clean (!) ground or surface water). Internationale Weiterbildung und Entwicklung Gmb. H
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 32 Modern Irrigation Methods in Semi-Arid to Wet Zones Only a selection: E. g. Channel Bank Irrigation WUE is about 45% : Surface Irrigation, Auto Flood and Flood (e. g. wild flooding, contour flooding, borders, channel, basin, etc. ). Small diameter pipes used to convey water over the channel embankment (source: FAO) Internationale Weiterbildung und Entwicklung Gmb. H
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 33 Modern Irrigation Methods in Semi-Arid and Semi-Arid Zones Only a selection: A) Surface Drip Irrigation Water Use Efficiency (WUE) is about 97% : Localized Irrigation (e. g. drip resp. trickle, subsurface drip, bubblers, microsprinklers etc. ). fig. source: FAO e. g. four emitter or dripper for trees e. g. one emitter for outdoor vegetable Internationale Weiterbildung und Entwicklung Gmb. H
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 34 Modern Irrigation Methods in Semi-Arid and Arid Zones Only a selection: : Localized Irrigation (e. g. drip resp. trickle, subsurface drip, bubblers, microsprinklers etc. ). B) Water Use Efficiency (WUE) is about 97% Internationale Weiterbildung und Entwicklung Gmb. H
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 35 Modern Irrigation Methods in Semi-Arid and Arid Zones Only a selection: : Localized Irrigation (e. g. drip resp. trickle, subsurface drip, bubblers, microsprinklers etc. ). C) Water Use Efficiency (WUE) is about 97% Internationale Weiterbildung und Entwicklung Gmb. H
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 35 a Soil Water Availability for Plants - some Basics: fixed water not available coarse texture Plant available water lost water runoff percolation fine texture (e. g. loam) Internationale Weiterbildung und Entwicklung Gmb. H
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 36 Effects of Traditional & Modern Irrigation Methods: Only a selection: : The problem of Salinization occurs with nearly any type of irrigation in arid zones. Especially with sprinkler irrigation and loamy soils. : Soil structure and soil texture also have an impact on and thus on water management efficiency: water losses from evaporation or runoff are either reduced or increased when soil structure is modified. : Soils developed under arid and semi-arid conditions can be changed irreversible by irrigation, solely the soil structure is more fragile than anywhere. : Generally, on a long-term basis, large-scale sprinkler irrigation is a delicate tool that can endanger the farming system's sustainability (long-term profitability) instead of increasing it: : Potentially, it can shrink the biodiversity, cause irreversible soil property changes, can dry out underground and surface water resources, and last but not least, it can be too expensive forthcoming generations. Internationale Weiterbildung und Entwicklung Gmb. H
Dr. H. Kehl Ecosystem Analysis and Integrated Ground Water Management The General Pre-Condition for Arid Areas 37 SALINIZATION = Land Degradation = Productivity is Diminished: Salinization are most commonly associated with excessive water application, rather than with too little! The Salinization refers to a build up of salts in soil, eventually to toxic levels for plants. 3, 000 - 6, 000 ppm salt results in trouble for most cultivated plants. Salt in soils decreases the osmotic potential of the soil so that plants can't take up water from it. When soils are salty, the soil has greater concentrations of solute than does the root, so plants can't get water from soil. The salts can also be directly toxic, but plant troubles usually result primarily from inability to take up water from salty soils. Internationale Weiterbildung und Entwicklung Gmb. H
Dr. H. Kehl Ecosystem Analysis and Integrated Ground Water Management The General Pre-Condition for Arid Areas 38 SALINIZATION = Land Degradation = Productivity is Diminished: : Salinization may occur with nearly any type of irrigation! EGYPT: The High Assuan Dam made year-round irrigation possible (and necessary!!) and prevented the annual floods, which led to increased salinization in the land irrigated by the canal system. Therefore, leaching and drainage takes additional water (Dregne, 1983; El Baz, 1988; Goossens et al. , 1994; Mainguet, 1994). Large areas around the Egyptian Oasis Kharga and Dahkla became unproductive through irrigation mismangement with fossil water. Additionally, although best available irrigation technologies have been implemented in the Wadi Natrun area (N-Egypt) repeated cycles of groundwater led to toxic brackish water tables. Source (partly, and modified): ICS-France 2003 Internationale Weiterbildung und Entwicklung Gmb. H
Dr. H. Kehl Ecosystem Analysis and Integrated Ground Water Management The General Pre-Condition for Arid Areas 39 SALINIZATION = Land Degradation = Productivity is Diminished: : Salinization may occur with nearly any type of irrigation! Iraq: In Iraq, there is a historical record of salinization caused by canal irrigation between 2. 400 and 1. 700 B. D. , and this problem has recurred at intervals through the present (Dregne, 1983). About 11. 48 million hectares (ha) of land is cultivable. However, FAO estimates for 1998 reveal that only 5. 5 million ha is put under cultivation due to soil salinity, fallow practices and the unstable political situation. 64% of the cultivated land was irrigated. Agricultural water withdrawals accounted for 52% of total renewable water resources. Source (partly, and modified): UNESCO 2003 Internationale Weiterbildung und Entwicklung Gmb. H
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 40 General Pre-Conditions and Limitations for Arid Areas Limited Ground Water Resources: !RISK: The overutilization of limited (fossil) ground water resources. . . : As it has been mentioned yesterday, between 1980 and 1995, Saudi Arabia consumed 75% of the proven reserves of fossil ground water in its major aquifers to irrigate wheat crops. FTGW, 1997 : Libya (Great Man-Made River) and Egypt (New Valley resp. Toshka Agribusiness Mega-Project) both, are on the way to use up their huge - but limited (!) - non-renewable fossil ground water reserves. Internationale Weiterbildung und Entwicklung Gmb. H
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 41 General Pre-Conditions and Limitations for Arid Areas Limited Surface Water Resources: !RISK: Evaporation losses of limited surface water through dams. . . E. g. : The water loss from Lake Nasser in the South of Egypt is one of the national problems. . . the evaporated water range between 10 to 16 billion m³/y which represent 20 to 30% of the Egyptian income from Nile water. Mosalam Shaltout & El Housry, 1996 Internationale Weiterbildung und Entwicklung Gmb. H
Dr. H. Kehl Ecosystem Analysis and Integrated Ground Water Management Just enough is best! 42 "It is the universal fallacy of humans to assume that if a little of something is good, then more must be better. In irrigation (as indeed in many other activities), just enough is best. " (Prof. Daniel Hillel in FAO Publ. 1997). As we have seen, agriculture is the highest fresh water consumer, especially in arid zones with LDCs. Therefore future agricultural extension policy must focus predominantly and early enough on Impact Assessment AND long-term Economic Evaluation of water harvesting techniques in arid zones. Internationale Weiterbildung und Entwicklung Gmb. H
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 43 AND: New is not always better. Water from "improved wells" is often only marginally better in quality than water from traditional sources — and it generally demands a costly or risky change in management techniques. Internationale Weiterbildung und Entwicklung Gmb. H
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 44 AND: Monitoring is important: to determine the nature and extent of change; to see if technical results match expectations; and to tell whether new management methods are actually adopted. Internationale Weiterbildung und Entwicklung Gmb. H
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 45 IDRC (International Development Research Center) supported research has explored the use of non-governmental “social auditors“. These community leaders identify interests and arguments that might not otherwise be heard. They also stimulate debate and discussion within and between communities. Internationale Weiterbildung und Entwicklung Gmb. H
Dr. H. Kehl Ecosystem Analysis and Integrated Ground Water Management 46 Population, Lifestyle, Culture, Governance, Policies Re-Adaptation to the Environment The Tripartite Inter-Relationship vir Se onm rv ice enta l s s IMPACTS & SERVICES Im pa ct En nd ra s bo on La tituti Ins Land Climate Hydrology Ecosystems Biota nd sa od ces Go ervi S WATER THE KEY RESOURCE Society Environment Natural Resources Economy Impacts adapted from Gallopin & Raskin 2002 Internationale Weiterbildung und Entwicklung Gmb. H Agriculture Households Industry Transport Services
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 45 Consequences for arid areas with low annual precipitation amounts and potentially high evaporation : Any given environment can spend only a limited service fo a limited population. It is embodied by the carrying capacity of its ecosystems, manifested and indicated by long-term adapted plants and animals through a longlasting evolution. It is therefore, and once more, essential to understand monitor these ecosystems. : The given natural vegetation of arid and semi-arid zones indicate its possible durability and simultaneously its utilization (and possible impact!) by human beeings and their economy. Internationale Weiterbildung und Entwicklung Gmb. H
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 45 Consequences for arid areas with low annual precipitation amounts and potentially high evaporation : If the only renewable and most essential water source is RAIN, it is also essential to prevent it from - every - nonproductive evaporation. : Therefore rain water has to be carefully harvested and protected below the soil surface. The same is true for flood water which should be guided to sites with favourable (infiltratable) soil conditions for crops. : Generally, a set of different and advanced techniques suitable for small-scale water management should be applied. Internationale Weiterbildung und Entwicklung Gmb. H
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 45 Consequences for arid areas with low annual precipitation amounts and potentially high evaporation : If ground water discharge is necessary during the dry season a recharge during the wet season is a precondition for a long-term sustainability of the given ecosystem. : And last but not least, affortable and sustainable agriculture in arid areas needs a high intensity of labour, as it has been since ancient times. It is adequate for selfsufficiency and can provide additional food for local markets. Internationale Weiterbildung und Entwicklung Gmb. H
Ecosystem Analysis and Integrated Ground Water Management Dr. H. Kehl 47 Questions and Discussion of Today 1 What kind of co-operation between dicision-makers and affected low-level people (especially village-level institutions) is possible and what has been realized? What are the main problems? 2 What criteria and options for appropriate irrigation methods have been choosen and implemented in your - different - countries to ensure a sustainable ecosystem management? What are the ecological effects on native vegetation of large-scale and smallscale irrigation projects? Internationale Weiterbildung und Entwicklung Gmb. H
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