Managing water for sustainable agriculture
Water for food and rural development
ICID Triennial Congresses
In most countries, the agriculture sector is the predominant consumer of water. In many cases, irrigated agriculture has played a major role in the development of rural economies, supporting economic growth and poverty reduction.
Although enough food is being produced to feed the world’s population, there are still some 850 million undernourished/hungry people in the world. With nearly the same water and land resources base, we shall have to grow enough food to additionally feed about 2 billion people. Considering the increased demand resulting from expected increase in the standard of living, we need to double the level of food production. Securing our food supply is not negotiable. We all need safe and good-quality food in order to live a healthy life.
However, increasing water productivity holds the key to future water scarcity and food security challenges. There is scope for an accelerated increase in water productivity. Water productivity in agriculture has increased steadily in the recent decades, largely owing to increasing crop yields, and the potential exists for further increase. However, the pace of such increase will vary according to the type of policies and investments, with substantial variations in the impact on the environment and livelihoods of rural populations.
21st ICID congress shall provide an opportunity to exchange updated knowledge and researches on Irrigation, Drainage and Flood Control that contribute to enhanced food production with less water, and better protection from uncontrolled flooding.
Today, agriculture consumes 70 percent of all global water withdrawn for consumptive use, up to 95 percent in several arid and semi-arid countries. Increasing the efficiency of soil and water use and enhancing agricultural land and water productivity at all levels of the production chains are becoming priorities in a rapidly growing number of countries. A systematic approach to agricultural land and water productivity requires actions at all levels, bottom to up, crops to irrigation schemes, and national to international economic systems, including the trade in agricultural products. It calls for an informed discussion on the scope for improved land and water productivity in order to ameliorate intersectional competition for water resources and optimize environmental, social and economic outcomes.
No doubt, irrigation should play a greater role to meet the food demand of the 3rd millennium by focusing on land and water productivity, while preserving rural employment. Researchers are invited to submit their papers on the following sub-topics:
Sixty Percent of world harvested crops is coming from rainfed agriculture covering 1.2 billion hectares of land. There are also six billion hectares of natural grass land and pastures which are contributing to human food chain. In spite of such a vast rainfed area available to the human utilization its contribution to the global food security is limited. No proportional efforts have been put forward by governments, international agencies and concerned NGOs to enhance the benefit of such natural resources. Little development has been contemplated to the traditional dry farming in past decades, particularly in developing countries. The productivity of rainfall, so called green water, in these regions is relatively low and there are considerable rooms for improvement, through rainfall management, agro-technical and agro-business innovation, investment in infrastructures and technology accompanied by biotechnology enhancement to introduce appropriate varieties of crops.
CONCLUSIONS AND RECOMMENDATIONS
It is well recognized that irrigation and drainage as an integrated water management system for agriculture has been critical to increasing crop yields and productivity in the agricultural sector. Improvement in the productivity of irrigated agriculture is seen as important component to meeting future world food demands. At the same time, these agricultural systems must be sustainable - based on renewable water supplies and in harmony with the environment.
This question is presented in terms of 6 subtopics:
Q52.1 : On farm water and soil management
These subtopics have some overlapping issues.
General observations and recommendations
Q52.1 : On farm water and soil management
(1) Improvements in water use efficiencies for field irrigation systems are possible. While the physiological efficiency of the crop may not change, improved irrigation can result in less non-productive consumption and greater harvests through better cultural and harvesting practices. If water use efficiency is defined in terms of water supplied, then it can be increased by reducing the application of water that is not consumed.
(2) Technology can be applied to help farmers improve water use efficiencies in a variety of ways
(3) Papers from this congress appeared to give conflicting reports on the impact of partial drying of rice paddies, for example partial ponding, sprinkling, etc. These difference may result from different rice varieties, different soil conditions, or different climatic conditions. These need more investigation.
Q52.2 : Performance evaluation and integrated management
(1) An important issue in most irrigated regions is to improve the basin-wide overall efficiency of water use. This include all uses of water; agricultural, urban, industry, environmental, navigation, etc. While some progress has been made on this issue in isolated areas, this should be a major focus of future ICID activities.
(2) The operations of irrigation water supply systems often have a significant effect on the environment and other water needs. Consideration of these other uses should be included in operating plans and associated performance measures.
Q52.3 : Conjunctive use of water to optimize food production
No report was available
Q52.4 : Policy options for water saving in irrigation
1. Systems modernisation and introduction of new on-farm technologies imply
3. Explore obstacles to government subsidies and incentives for modernization at system and on-farm level
4. Address the increasing weight of energy in irrigation farm costs, in relation with pressurized systems and groundwater exploitation
5. Better analyze the reasons for failures in modernization programs, and possible remedies esp.:
1. Involving private stakeholders associations in the various management activities is essential.
2. Providing opportunities for cooperation and coordination between the government and the stakeholders is important.
3. The need for proper mechanisms for incentives, monitoring and evaluation of the performance of WUOs.
4. The need for a proper legal framework to support the establishment of Water User Organizations (WUOs) as well as providing autonomous structure for them.
5. Prerequisites for successful task transfer to private associations should include a firm policy decision to transfer a meaningful level of responsibility over the management of irrigation system to private associations\Water User Organizations and capability within public irrigation agencies to provide technical and institutional support to their associations.
6. The existence of Capacity, Autonomy, Effectiveness, Accountability, Relevance, Legality and Mission at the associations/ Water User Organizations (WUOs) is necessary for guaranteeing successful task transfer.
Q52.6 : Application of information technology in irrigation and drainage management
(2) In all this the need for greater water use efficiency and productivity has remained the main driver of many new innovative application of IT that has rapidly been gaining momentum in irrigation and drainage management. Some of the IT strategies are based on spatial and temporal database and utilising remote sensing (RS), decision support systems (DSS), web-technologies and automatic control systems. The database include wide ranging information such as cropping patterns, soil types, daily ET, precipitation, irrigation water deliveries, water orders, asset information, crop yield, specification of irrigation infrastructure.
(3) The papers revealed some pioneering efforts in developing skills and knowledge for efficient and sustainable irrigated agricultural production utilising information technology for on-farm water management, to regulate the systems and for asset management. They showcased the creative strategies of employing information technology to ensure higher productivity for less water and land use.
(4) The systems and strategies advocated in the papers are not yet optimal, but they showed tremendous promise. They should inspire all of us in the ICID family to experiment with or even utilise them and to contribute in further fine-tuning and developing the skills and knowledge needed to optimise them for greater efficiency and sustainable production.
Floods are a recurrent phenomenon from time immemorial. Almost every year floods of ranging magnitude affect certain parts of countries. Floods may be caused by excessive snowmelt, heavy rainfall, cyclones, typhoons, etc. With the increase in development activities and occupation of floodplains, the magnitude of damages and losses has increased. In ICIDs work the focus is on the river floods. Flood issues were discussed under six themes and the following general and theme specific observations and recommendations emerged.
General observations and recommendations
(1) While flood protection measures have been attempted since long, levels of protection are generally below the economic optimum, especially for urban areas in flood prone zones. When an extreme event occurs, losses in terms of human lives and property are generally considerable.
(2) Costs of only physical solutions to reduce flood risk are generally unaffordable. With the limitations in physical solutions for flood protection and control, there is a need to move towards improved flood management approaches. A river basin approach with integrated flood risk management will generally be required to find optimal solutions. In such a holistic flood risk management approach, the design of hydraulic structures would have to be based on economical and efficient considerations. The drastic change in policy from flood control to flood management that China recently has made may serve as an example.
(3) For analysis and planning of appropriate solutions, reasonable databases need to be generated, a classification or categorization of the nature of floods, including the possible effects of climate change, needs to be made and methodologies need to be developed for realistic assessments of flood damages.
(4) Water resource management including floods and land use planning are to move close to each other. It is vital that the mechanisms that lead to floods and droughts and the physical effects are fully understood, before mitigation and response measures are planned and implemented. Flood Risk maps and floodplain zoning may help in reducing damages.
(5) There is a need to shift from traditional flood relief measures to effective and efficient water management, including flood risk management. Such a management will be dependent on adequate polices and legal measures, sound institutional arrangements and funding. The appropriate institutional arrangements for flood management are necessary for study, planning, design and implementation of flood protection and management schemes. Coordination between the various agencies dealing with dikes, as well as with rail and road embankments and other works in floodplains is essential.
(6) Flood forecasting will generally be a useful tool in operating large reservoirs and advance actions for evaluation of human habitation, where needed. For adequate follow-up actions after a flooding a suitable mechanism for relief and rehabilitation needs to be in place.
(7) In many cases maintenance of flood control infrastructure needs more emphasis.
(8) With respect to flood management in international rivers, cooperation between riparian countries is essential.
(9) Increase or contribution to pollution levels arising out of floods need to be carefully monitored. Measures to control pollution will have to be taken shortly after an incidence of flooding in such cases. Post flood recession needs suitable acceleration to minimize spread of epidemics and health hazards.
Observations and recommendations per theme
53.1 : Land use planning and its impact on flood and drought regime and 53.3 Adjusting urban and rural development to reduce flood risk
1.1. Water management and land use planning must not be independent activities - rather they are interdependent activities. It is the interaction of floods and drought with land use that is the cause of concern for human society. The interruption of established land use by flooding and, more chronically, by drought, can have severe consequences on both the lives and livelihoods of people and the communities in which they live.
1.2. It is therefore disappointing that only one suitable paper on theme 53.1 was submitted. The paper addresses the mapping of soil moisture content and its spatial and temporal variability, which are important determinants for both the chance and timing of floods and droughts. The benefits of this knowledge go beyond land use planning and extend to agriculture and water management generally, including the health of the natural environment - ecosystems and habitat.
1.3. Climate change will impact on soil moisture, as both precipitation and evaporation patterns will be affected. There is now greater consensus amongst meteorologists and others that man-made climate change is a reality. Carbon emissions from the atmosphere over millions of years, is now being released back into the atmosphere in decades, leading to increasing global temperatures. Although there is some uncertainty about the precise effects, it is accepted that oceanic seawater will expand, and that ice caps will melt more rapidly, leading to sea level rise. The warmer atmosphere will lead to more severe weather extremes - droughts and floods will become more frequent.
1.4. Against this background, the suitability of land for both agriculture and urban use will change. Areas, which are marginal for agriculture at present, may not support crops and grazing in the future without irrigation. The availability of water for irrigation will also be affected. The flood risk to low lying coastal communities, or those in river valleys, may increase to the point where protection by dikes is no longer viable. The potential impacts of these changes on food security, human safety and economic stability are very serious.
1.5. It is obvious that both urban and rural communities are vulnerable to weather extremes and their consequences. Flood damages are a function of both peak discharges - and therefore both the depth and extent of floodwater - and the duration of flooding. The benefits of catchment based planning and the value of sustainable drainage systems will have to be taken into account.
1.6. Land use planning will need to consider risk. This refers to the chance of adverse circumstances and their consequences, as well as to primary measures to reduce the chance of a flood or drought. Measures to address residual risk need to be considered if the consequences of failure of primary measures are sufficiently serious.
1.7. A typical and tragic example serves to illustrate, the city of New Orleans was known to be vulnerable to flooding and defences were put in place to provide a degree of protection. However, as is now evident, there were no means of preventing most of the city from floodwater in the event of a breach of a dike. Buildings and services were vulnerable to flooding and many people had no personal strategy for coping with the flooding. In addition, measures to improve navigation in the River Mississippi such as new channels and dredging of existing channels, may have served to increase vulnerability to a storm surge. Development on the coast of the Gulf of Mexico appears to have increased the exposure of people and property to the potential hazard. As a result, both the chance and consequence of flooding were increased - but there seems to have been no systematic monitoring of the changing situation.
1.8. In the rural situation, agricultural land use can have a significant impact on both floods and drought. Good practice, such as preventing deforestation, providing buffer strips along the banks of rivers and contour ploughing can reduce sediment runoff, maintain soil moisture and limit pollution. Similarly, natural drainage patterns and geomorphologic processes need to be understood and respected. The natural environment has developed to cope with prevailing conditions. Serious disturbance of the balance can increase vulnerability to extreme weather and lead to desertification or waterlogging.
53.2 : Integrated planning and management of flood diversion, storage, retention and discharge areas
2.1. For efficient and powerful planning and management of flood issues integrated approaches are needed and appropriate administrative systems will have to be in place. Although each individual measure of flood management is important, integration of measures and their complimentary role gives them added effectiveness. Floods are inevitable in a certain time scale in flood prone areas. We need wisdom and knowledge and to be prepared not only for the normal floods, but also for extreme floods, which are beyond the design standards. Integrated planning and management of flood management measures with respect to extreme floods were presented. In such cases it is vital to consider how the administration and people will respond to a flood, like in the case of New Orleans. However, an important question remains how comprehensive flood management measures, by integrating structural, non-structural and watershed approaches, would have to be done under the different location specific conditions remains.
2.2. Local traditional measures are important. This especially concerns the multi-functional role of paddy fields with respect to their flood detention effect. In the Asian monsoon region, water use is well integrated because of the sustainable water use in agriculture. From the point of view of watershed management, paddy fields help to regulate floods by serving as retarding basins. This way of coexistence with floods was, for example, presented in the case of Lake Tonle Sap and the surrounding paddy fields in Cambodia. Here floodwater storage in paddy fields concerns more than 20% of the total storage volume. However, it was expressed that in India and Pakistan this role may not always be feasible.
2.3. For the coexistence with floodwater we need to think more about the use of floodwater especially for agricultural use by spreading, storing, etc. Agricultural management can make a sound contribution to flood risk management though good practice. In line with this approach the considerations underlying the recent change in policy with respect to flood management in China were clearly presented. Several interesting and important ideas were introduced. Comprehensive approaches including keeping equity in communities will have substantial advantages for flood management in the near future. This was, for example, illustrated with the flood control system and philosophy in the Hanjiang River. The structural flood management and its harmonious modification make this example of use for other countries.
2.4. Improving risk management for flood and drought is necessary for the safety of flood control works. Under the progressive urbanization keeping the capacity of water storage or infiltration as in the farmland is efficient for mitigating the level of floods. The effect of urbanization to flood peaks will have to be evaluated and included in the design of the hydraulic system. The same concerns the potential effects of climatic changes.
2.5. Training for flood mitigation, peoples' participation to flood fighting and equity in community are important.
2.6. Ecological effects on rivers of projected hydraulic works need to be seriously considered, before decisions on such works are taken. In the development of flood management plans the potential environmental benefits will have to be accommodated as well. ICID will have to promote that due attention is being paid to this aspect.
2.7. Some papers dealt with the basic aspects of structures for flood protection, like improved hydraulic structure design, capacity of present storage infrastructure and structural measures of protection against floods. Coexistence with floodwater in the river foreland between the dikes was introduced for the Indus River where around 590 spurs and 5,800 km long dikes have been constructed. In such cases people live, cultivate their lands and coexist with the floodwaters, like their normal life.
2.9. The Piano Keys Weir was presented as a new low cost solution of a free-flow spillway for increasing the specific flow by a factor 2 to 4. The weir is also applicable for reducing the cost and/or increasing the storage of dams. It may be combined with gates for optimised management of floods. Most of the examples applied to irrigation dams and to reservoirs for drinking or industrial water, which are usually managed as irrigation reservoirs.
53.4 : Mechanism for protection relief and rehabilitation
4.1. Floods may cause considerable damage to environment, by affecting agriculture, humans and nature areas, due to release of pollutants from farms, households, industries and cars. In this example cars may release more serious pollutants than other sources. This needs to be assessed in order to be able to take remedial measures.
4.3. Where floodwaters are stagnant over long periods of time and people live on mounds or dikes, prevention of erosion due to waves is important. Planting of trees which can grow in standing water and other hard protective measures may need to be taken as per site requirement. There is a need to find cost effective measures to provide sustainable and equitable solutions.
4.4. Immediate relief after occurrence of a hazard is providing safe drinking water to people who have been rescued. Regular water supply schemes have to be restored immediately thereafter. If applicable, impact of salinity has to be eliminated as a long-term measure. Informing the public of the measures taken will have to go a long way in getting them prepared for such hazard situations.
5.1. Flood management strategies are essential for flood risk prevention and preparation. They have to be integrated, taking into account technical, but also socio-economical aspects under consideration. Some countries are more prepared than others and would have to share their expertise.
5.2. Flood modelling may play an essential role in the development of a flood management strategy. Simulations can serve to illustrate the efficiency of strategies and therefore of the hydrological risk. Collection of data will play an important role in ensuring the quality of models used.
5.3. A flood management strategy will have to be adapted to the geographical scale and to take into account local specificities (events, land use, population, economic development, etc.).
5.4. The population concerned by potential floods has to be prepared. Communication techniques will therefore have to be developed, for acceptance of risks and their consequences.
5.5. ICID has an important role to play in this context. It has to convince their own members to contribute more and more to the development of those strategies, even in the rural areas.
53.6 : Case studies
6.1. Most case studies dealt with examples from Asia and were of a technical nature. However, there were also papers of a different nature. They dealt with institutional aspects, community initiatives and recovery of fish catch.
6.2. One paper showed lessons to be learned from the history of the Kurit Dam in Iran, the world's highest dam from 1350 until the early 20th century. Although the dam was built 650 years ago, it still serves as an illustrating example of harmony with floods, sustainable development and coping with uncertainties.
6.3. Floodplains in developing countries are among the most populous regions in the world. Natural disasters due to water related hazards such as floods and inundation are severe in such countries. A wide variety of structural, non-structural and watershed measures have been adopted for flood control and management. The participation of the community in flood control and management is on the increase. Integrated flood management with a judicious combination of structural, non-structural and watershed measures has become increasingly significant in developing countries. Where floodwaters cannot be prevented, suitable conditions will have to be created to live with them. Many such practices originated as community initiatives and were finally adapted as the government strategies. The recent tsunami disaster has highlighted the vulnerability of coastal zones. Long-term rehabilitation programs will have to cover livelihood and ecological secutiry.
Irrigation is a common denominator among all participants in this international event, and we have come here to exchange our views and experiences within the concept of irrigation science and technology to meet the ever increasing demand on global food production. But this ambition, by no means, has a simple and straightforward path to follow.
In this particular symposium, we are going to look at a very delicate issue of irrigation related to the environmental consideration, as well as, the economical viability of consuming saline water and drainage reuse while maintaining the livelihood of irrigated agriculture.
On the other extreme, new approaches to soil and water salinity management have been put forward by researches and practitioners such as minimum irrigation water application, bio-drainage, dry-drainage, shallow groundwater consumptive use, and many other ideas in order to control the important balances of salts, particularly in the saline soil and water environment. But there are yet questions to be answered, such as; how to monitor this critical process? What are the appropriate indices to be considered and used? What is the effect of irrigation system on the soil salinity balance and salt redistribution? What are the economical consequences of salt management in the soil profile? Should we consider the livelihoods of downstream water users who are relying on the drainage reuse?
It seems we are faced with dynamic and multidisciplinary decision making processes which should be dealt with in integrated and holistic manners. From the review of the papers, their presentation and our discussion it became clear that holistic, multidisciplinary and innovative approaches to the problem of water quality and salinity management are being researched and applied.
Symposium results :
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