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Annex VIII



This paper discusses management-based strategies for flood and drought prevention and mitigation, with a brief introduction on the general problems that impinge on water resource management. Floods and droughts are central to the latter and should therefore be considered in any analysis of river basin management. A detailed presentation on their nature and the types that affect Asia, their occurrence and impacts, particularly on agriculture and food production, together with the impact of climatic change on their future intensity and frequency are also given. Strategies for sustainable development, food security and environmental preservation are recommended. Regional experiences and trends and the difficulties and complexities associated with them are examined. The paper concludes with some recommendations that may assist countries in the region improve their flood and drought mitigation measures.


1. Water flow is unevenly distributed over the earth's surface, and much of it occurs in seasonal floods because of spatial and temporal variations in precipitation. Only an estimated 9,000 to 14,000 km3 per year (8 to 13 per cent of rainfall) can be potentially controlled with technical, social, environmental, and economically feasible water development programmes. At present, about 3,400 km3 (3 per cent) is for various uses, of which, irrigation is the most predominant, accounting for about 70 per cent of the total. Others are for domestic and industrial purposes and are largely non-consumptive in nature. Hydropower, ecosystems, navigation and recreation are also important consumers of water.

2. By 2025, a third of the developing world's population will face severe water shortages. Even a small country like Sri Lanka can experience acute water scarcity throughout the country due to fluctuating availability and demand (Amarasinghe, Mutuwatta and Sakthivadivel, 1999). Districts such as Galle, contrary to common belief, are confronting worsening shortages. However, in many arid regions, large amounts flow out to the sea annually. Some of this flush salt and other harmful products out of the system and thus assist in maintaining the ecological quality of estuaries and coastal areas. But in many cases, floodwater is not fully utilized and it can do a great deal of harm (Keller, Sakthivadivel and Seckler, 2000). As more and more people live in flood prone areas, they tend to transform these precarious regions into climatic disaster zones. Flood and droughts represent 36 and 3 per cent respectively of estimated damages from major types of natural disasters in the 1990 to1999 decade (IFRC, 2000).

3. There is however a move in water resource management (Gleick, 2000) to efficiently tackle the problems brought about by floods and droughts by adopting fewer structural measures and placing more emphasis on ecological values. Old paradigm infrastructures are beginning to fail and water demand is changing with decreasing use particularly in developed countries. The "new paradigm" can be described as follows:

  1. basic human needs must be satisfied,
  2. basic ecosystem requirements for water must be met,
  3. use of non-structural alternatives to meet demands must receive higher priority,
  4. economic principles must be applied more frequently,
  5. new supply systems, when necessary, must be flexible and efficient, and
  6. NGOs, individuals, independent research organizations, and all other affected stakeholders must be involved in water management.

4. This rethinking is permeating not only developed but also developing countries where efforts are being made to integrate water use and the maintenance of sound ecological and environmental health. Policies and institutions are undergoing changes to increase the efficiency of water allocation. Integrated watershed management is currently recognized internationally as an important holistic approach to natural resource management, which seeks to promote the concept of sustainable development. Such an approach has been recommended in Agenda 21 for all sectors dealing with the development and management of water resources.

5. Human intervention alters the natural hydrological cycle. Freshwater ecosystem provides food, water purification, storage, recreation, cultural, aesthetic and spiritual needs. Nevertheless, for civilizations to survive, it is imperative that water use is managed efficiently. Attempts to control floods and droughts have not been quite successful and it is important to recognize that extreme weather patterns are natural phenomena that will continue to occur. It is essential to learn to live with them.

6. Watersheds are units of the landscape that contain a complex array of inter-linked and inter-dependent resources and activities that are not determined by political boundaries. Land resources such as soil, water and vegetation cannot be managed in isolation from each other. Their natural balance can be easily disrupted by changes in land use or poor planning. Proper management recognizes the successful preservation and protection of the prevailing environment. The broad objective is to develop policies that promote sustainable use of such resources, taking into consideration the economic, social and environmental issues associated with them.

7. However, in densely populated developing countries, the main organizational bottleneck lies in the extensively subdivided and tremendously diverse use of land by millions of small farmers or tenants, who often cannot look beyond the next harvest. For governments, it is almost impossible to approach them individually. In such a situation, it is sometimes argued that it is better to speak about `watershed development', which not only concerns the physical resources of land and water but, to a large extent, also of human resources.

8. Except for long-term climatic changes, the average annual water supply in a river basin from past and present precipitation is constant. Thus, unless it is technically and economically feasible for trans-basin diversions or desalting of seawater, any population growth and economic activity within it will inevitably increase water scarcity (Seckler, 1996). This problem becomes even more acute when supply and demand vary dramatically for different seasons. In the wet season, when demand is low and supply plentiful, its marginal value is nil, but in the dry season, the situation is reversed.

9. The problem of water management lies in the fact that its sporadic, spatial and temporal distribution rarely coincides with demand. Whether it is for natural processes or human needs, the only way supply can match demand is through storage. A water resource system is "closed" when there is no usable water leaving it (Keller, Keller, and Seckler, 1996). Conversely, it is "open" when the reverse happens. The majority of crucial policy questions in the water resource field depend on the degree of closure of these systems, and on a thorough understanding of their integrated nature. As a river basin begins to close, it becomes increasingly more difficult to save water, and tradeoffs emerge among the different opportunities for water conservation.

10. Many rivers in Asia, including those in the humid tropics are closed, semi-closed or closing rapidly. The Chao Phraya River is now almost closed for all practical purposes; there is very little unallocated water even during the wet season (Molle, 2001). The main rivers in China1  are also closing (Burke, 2000). This is also the case for the basins studied by the International Water Management Institute (IWMI) in South Asia (Molden, Sakthivadivel, and Habib, 2001). Semi-closed basins present major opportunities for adding value to water through storage. Man can create and enhance it by conserving water during tillage, constructing dams and dikes for impoundment, and artificially recharging groundwater. Regardless of the method or type of storage, the purpose is to capture water when and where its marginal value is low or, during floods when it is negative, and reallocate it for use when and where its marginal value is high.

11. Water problems comprise the single most complex constraint to increasing food production and socio-economic development in many parts of Asia and the Pacific, including India, China and Pakistan. Issues related to its distribution, consumption and price would be important challenges for land tenure in the early part of the new millennium (Riddell and Palmer, 1999). Since groundwater plays a particularly major role in achieving high yields, any emerging threats to it have serious food security implications at both local and possibly global levels. In India, irrigated groundwater areas account for approximately 50 per cent of total irrigated land and, according to some estimates, as much as 70 to 80 per cent of total agricultural production is dependent on groundwater. In many arid and semi-arid zones, it is the primary source for meeting both domestic and agricultural needs. In other regions, it assists in overcoming dry spells or periods of drought and supplements surface irrigation, thereby increasing the efficiency, reliability and flexibility of water supply and providing greater security.

12. This introduction gives a brief account of the general problems of water resource management in which flood and drought constitute the core issue. Subsequent sections of this paper will attempt to do the following:

  1. describe the nature and types of flood and drought affecting Asia, their occurrence and impact on agriculture and food production,
  2. examine the implications of climatic change for the future,
  3. discuss recommendations made to promote sustainable development, food security and the environment,
  4. analyse regional experience and trends in drought, flood, river basin and watershed management as contained in technical publications, projects and case studies,
  5. give a state-of-the art account of alleviation measures,
  6. discuss the difficulties, complexities, uncertainties and misconceptions encountered, and
  7. make some recommendations that may assist countries solve some of their water problems.


2.1 Floods

13. A flood can be defined as an excessive flow of water over land that is not usually submerged. Inundation brings disastrous consequences and can originate from various sources, including intense and prolonged rainfall, snow melt, blocking of river channels downstream by landslides or avalanches, failure of dams upstream, storm surges, abnormally high tides, and tidal waves. Table 1 describes most types of flood. The serious ones are caused by intense storms originating from tropical cyclones or widespread, prolonged and heavy rainfall from monsoon depressions. This produces inundation that lasts from a few hours to three weeks or more, depending on the catchment area and the nature of the river channel and its floodplain.

Table 1
Types of Flood2


Details and Examples


Riverine or non-riverine; Slow-onset or flashflood; Convectional/frontal/orographic; Torrential rainfall floods

Snow melt

Riverine; Overland flow

Ice melt

Glacial melt water

Flooding during freeze-up


Flooding by ice break-up

Riverine (ice-jam floods)

Mud floods

Floods with high sediment content; Induced by volcanic activity

Coastal/sea/tidal floods

Storm surges (tropical or temperate induced); Ocean swell floods;
Tsunamis (induced by geological processes)


Dam-break flood; Dam overtopping; Failure of natural dam

Sewer/urban drain flood

Storm discharge to sewers and drains excess capacity

Water distribution failure

Burst water mains; Breaches in canals

Rising water tables (high groundwater tables)

Land subsidence, rising sea levels, reductions in abstractions from aquifers

14. The following characteristics of floods govern the magnitude and cost of their disastrous effects:

  1. peak depth, extent and seasonality which determines the extent of damage to buildings and crops and the feasibility and cost of mitigation measures,
  2. duration which determines the degree of inconvenience caused,
  3. rate of occurrence, which determines the effectiveness of early warning and evacuation procedures,
  4. velocity of flow which determines the feasibility and design of levees and preventive structures, and
  5. frequency which determines the long-term average costs and benefits of corrective measures.

15. Flood behaviour which involves many variable factors and influences, is an intricate hydrological process that follows the mechanics of run-off. Its complexity increases with the size of the catchment. A small upland watershed may be entirely different from a large river basin of which it is a part. There are various forms of temporary storage through which water must flow as it meanders to the catchment. As the river fills and subsequently empties, these motions delay and attenuate its flow. Floods usually peak some time after the height of a storm and they cause the river to swell. The overflow in very small watersheds may be a matter of minutes or at worst a few hours, but in large river basins it may be several weeks and in extreme cases, several months.

16. As the total area drained expands, the effectiveness of upstream flood control measures lessens. This is primarily because the channel system's storage becomes more important. As the catchment size and its storage capacity grow, it determines the shape of the flood hydrograph. Thus it is possible to classify a "hydrological small" watershed as one so tiny that its sensitivities to short-term variations in rainfall intensity and changes in land use are not suppressed by its channel storage. A "hydrological large" watershed is one in which the latter governs flood behaviour and its sensitivities to rainfall and land use are largely suppressed. In terms of actual area, the upper limit for a "hydrological small" watershed may vary considerably according to the nature of the catchment, but it is probably in the range a few hundred hectares to a hundred or more square kilometers (ESCAP, 1997).

17. Riverine, flash, urban and coastal floods are most widespread in Asia. The first is common and it causes substantial damage. The densely populated floodplains of many countries experience frequent and devastating flooding. The inundation of the large river basins of the Ganges, Mekong and Yangtze is usually seasonal and may last for many weeks. This type of flooding, described as "hydrological large" is also associated with smaller drainage basins of rivers in north China, Japan and the Republic of Korea.

18. Flash floods are associated primarily with "hydrological small" watersheds and are usually caused by intense, short duration convective storms that produce very high rainfalls. The severity grows when their watersheds are steep and the surface infiltration capacity is low. The flood depth can be considerable and cause extensive damage. Because they occur very rapidly and with little warning, they cause substantial injury and loss of life.

19. Urban flooding can be experienced in watersheds of all sizes. When there is urban development in a catchment, storms can increase the volume and rate of run-off dramatically. This is due mainly to decreased surface infiltration capacity and concentration. Thus urbanization can significantly accelerate peak discharges during frequent storms.

20. In Asia, the most serious form of coastal flooding is from storm and tidal surges or tidal waves (tsunami). Strong winds, heavy rainfall and major flooding usually accompany them. Although their effects are restricted to a relatively narrow strip of coastline, they have the potential to cause widespread loss of life and property, particularly in densely populated coastal regions. Many disasters associated with tropical cyclones are from storm surges. Countries particularly susceptible to them are India (northern sector of the Bay of Bengal) Australia; Bangladesh; China; Hong Kong, Philippines, Republic of Korea, Thailand and the Pacific Island.

2.2 Floods and Agricultural Production

21. Floods can, on the other hand, be an advantage to agricultural areas, as normal ones which occur annually in many arable floodplains provide a vital source of moisture for crop growth, especially in arid, semi-arid and sub-tropical terrain where drought is a major problem and irrigation a necessity. One such form of irrigation is recession planting3. In Bangladesh, agriculture depends on regular flooding. Alluvial silt is also a source of additional fertility4. Floods benefit the ecosystem and human livelihood associated with them. However, when they occur in excess, many subsistence farmers lose their crop, productive assets and capital and may have to borrow or lose their land. Availability of low-cost credit and new technology to minimize crop loss must be introduced to assist such farmers.

22. The crop loss per hectare, however, is much lower in urban areas and it is thus getting increasingly difficult to justify the provision of flood mitigation (or a high standard of protection) in rural areas. The economic benefits of reducing crop losses can be rather insignificant as agricultural production is heavily subsidized. However, protecting such areas from floods may also be viewed in terms of food security, alleviating poverty, avoiding migration to the cities and other desirable social objectives.

23. From an agricultural viewpoint, water management rather than flooding merits greater attention. Too much or too little water is harmful to plant growth and yield. In temperate regions, drainage may be a larger problem than flooding as crop loss due to water logging may have occurred prior to flooding. In areas protected by a dike, local flooding within it can also destroy the crops planted in it. If the soil's water level is not regulated, then there is little advantage in attempting to control surface water. The extent of crop loss depends on when the flood occurs in the growing season and its duration. It can also prevent or delay planting of the next crop as well as damage the standing crop. In agricultural areas, it is land drainage rather than flood alleviation that offers the most benefit. Projects for the latter will have little or negative impact in cases where planting is dependent on soil moisture levels and in the absence of any drainage scheme. They may even impede the drainage of the protected area (Greene, et. al. 2000). Floodplains are an important source of grazing land, and livestock farmers may suffer from their conversion to arable land. Any loss of animals will mean that they can no longer be used for draft purposes. Although aquaculture benefits from normal floods, severe ones can destroy it.

2.3 Drought

24. It is defined as serious water shortage and implies some specification for the amount required and the purpose for its use. What constitutes aridity in a certain situation may not be the case in another. Because its nature and severity are dictated by weather conditions, it is difficult to predict its onset, intensity or likely duration. It is a recurring climatic phenomenon that should be distinguished from climatic change, although the latter determines its frequency. The vastness of the Asian continent implies a great variation in its climate, which can range from arid, semi-arid to dry sub-humid, and this makes it difficult to formulate a single strategic approach to drought management. It is thus imperative that an analysis be made regarding the risks associated with droughts in Asia especially their frequency and severity. They fall into the following categories (Mainguet, 1995):

  1. meteorological, where rainfall is deficient,
  2. hydrological, where runoff in rivers and the lake level decrease due to both the rill wash/infiltration ratio and evaporation caused primarily by indirect meteorological droughts, and result from short-term climatic changes that are normal in dry areas,
  3. edaphic, where the soil infiltration rate and the capacity of seed germination decrease, and
  4. agricultural,5 where water is deficient for planting.

25. The degree of dryness should be taken into account, namely, long-term, mid to short-term and short to mid-term, as this is often human induced and caused by land degradation. It is often difficult to diagnose the real effects of drought, even where there is general agreement that many environmental changes result more from short-term aridity rather than from long-term ones. It is more a question of whether recurring droughts are annual, biennial or multi-annual phenomena. Besides, it is difficult to differentiate climate-induced short-term environmental changes from land degradation resulting from human activities.

26. Dry lands experience violent changes in biomass (cover density and species diversity) and first-degree land degradation. These can be easily confused with the effects of human actions that cause irreversible desertification. When not aggravated by man, dry lands are resilient in that nature can, over time, restore the environment to its original state. Second-degree degradation refers to alterations made to dry land soil, and they are more difficult to discern and curb.

27. Drought is an intermittent problem experienced by all countries. Major ones occur from time to time in Australia, India and northern China, where considerable impact to the national economy is felt over a long period. Heavy loss of livestock, wildlife and natural vegetation, and human disease, starvation and extensive and permanent land degradation, are the likely outcomes of this type of natural disaster (ESCAP, 1997).

2.4 Food Shortage and Famine

28. Temperature and rainfall are critical elements determining when and how often crops can be sown. For the present, drought is the most dangerous climatic threat to production. But the environmental, socio-cultural, and political/economic causes of food shortage are inter-related. Although inadequate fertilizer or water may place limitations on production, the disruptions to fertilizer supply and irrigation systems are primarily economic in nature. Dry weather rarely leads to food shortage in the absence of armed conflict6.

29. The connection between drought and famine is therefore not as strong as earlier thought (UNU, 1995). Some of the complex relationships that cause food shortage are best appreciated in locations that undergo prolonged aridity. They demonstrate that this inadequacy is not inevitable in regions that experience even major production shortfalls if they have the capacity to respond adequately. Food security is a function of three factors, namely, (i) availability, (ii) stability, and (iii) the ability of individuals to get access to food. It is now apparent that starvation is due more to the inability to purchase supplies that are readily available in the market and not a matter of availability. Sen's entitlement approach describes "famines as economic disasters, not just as food crises" (Sen, 1999, quoted in FAO, 2001) It characterized the nature and causes of the entitlement failures where such failures occur. This is similar to the sustainable livelihood approach. The critical role that access to water plays in poverty alleviation has also been highlighted. Reliable water supply is the key to farmers' access to a wide range of development benefits. They, however, carry some degree of risk as farmers must make investments in fertilizer, seed and other inputs in order to achieve them. Such investments are often made on credit that will be lost when the water supply fails. When, for example, the groundwater level declines drastically, short-term risk exposure, primarily economic in nature, may return to the pre-irrigation era (Burke, 2000). Falling water tables affect the poor long before they have any impact on wealthy farmers and other affluent users. Thus, it is likely to have a major economic impact on farmers with limited land and other resources and would be particularly pronounced during droughts when many small ones could lose access to groundwater as their wells dry up. "Crisis" in such situations would be economic rather than related to food grain availability (FAO, 2001).

2.5 El Niño ENSO Events

30. There is increasing evidence to indicate that El Nino causes regions around the western Pacific Rim to suffer from severe drought. Its normal impact in Asia (Gommes, Bakun, and Farmer, 1998) in terms of increasing or decreasing rainfall is shown in Figures 1 and 2. In India, it is responsible for dryness during the southwest monsoon, and this reduces rice yields. In Thailand, there is similar negative impact on maize and rice. In the Philippines, aridity corresponds with the northeast monsoon season (a secondary season) and it causes poor rice yields. In Indonesia, it coincides with the dry season, which is a minor growing season, but its effects can be exacerbated by human behaviour such as open burning. Short-term drought can become long-term when water is permanently channelled away from agriculture to other uses. The reaction to extreme cases of El Nino must be seen in a broader context of developing strategies to tackle pronounced atmospheric phenomena and water-related disasters (Figure 3). It is hoped that their predictability can be significantly improved in the near future.

Figure 1.
Distribution of people affected by natural disasters, by country
and type of phenomena, in Asia (1975-1999)

EM-DAT: The OFDA/CRED International Disaster Database
(; email: [email protected])

Figure 2.
Distribution of natural disasters, by country and type of phenomena, in Asia (1975-1999)

EM-DAT: The OFDA/CRED International Disaster Database
(; email: [email protected])

Figure 3.
World-wide climatic impacts of warm ENSO events7

From Gommes, Bakun and Farmer, 1998

2.6 Flood Alleviation Strategies

31. The floodplains of the Asia and Pacific region are of environmental, historical and socio-economic importance. In Bangladesh 80 per cent of the total population is located in flood-prone areas. The implementation of alleviation measures must take into account regional geographical characteristics, the availability of arable land per capita, population density and economic factors (Tables 2 and 3). When farmland is scarce and population high, the potential to decrease the use of floodplains is limited. When the prevailing flood control technology is indigenous, the switch to modern alternatives will be particularly difficult in the short-term. Technology that is successful in some countries may not always be appropriate in others.

Table 28.
Arable Land Availability Per Capita
in Selected Countries


Arable Land
Per Capita (ha)

















World - average


Table 39.
Density of GDP and Population in Selected Countries

Country or State



New Jersey





















32. The following factors determine the implementation of flood control strategies in the People's Republic of China:

  1. very dense population,
  2. fairly intense economic activity,
  3. very little arable land per capita,
  4. landscapes and ecosystems are largely a reflection of past human activity,
  5. difficulties in enforcing land and building controls imposed by central government,
  6. floodplains that are settled for more than a thousand years,
  7. high proportion of flood prone, usable land,
  8. adoption of a wide mix of strategies, including the earliest known examples of flood warning, over the last two thousand years, and
  9. preventive measures undertaken by all levels of government but predominantly by the local authority.

33. Another feature specific to Asia is the importance of rice. Floods govern its productivity level and paddy cultivation plays a vital role in the hydrological cycle of river basins, mainly through groundwater recharge, flooding and evapo-transpiration. This is illustrated in Box 1. An assessment of land-water linkages to paddy in a drought or flood prone basin goes beyond the opinion that "rice consumes a lot of water". Several questions arise, e.g., in hill slope management, the crucial ones center on how proper terrace management can assist in storing water at the right time and thus reduce peak flooding, and the ideal sites to build new terraces to correspond with watershed lag-time to achieve greater efficiency (FAO, 2000).

Box 1
Positive Externalities of Rice Paddy in Japan

According to research by the Mitsubishi Research Institute and others:

1. Flood prevention: total water storage capacity of paddy fields in Japan is estimated at around 4.4 x 109 m3, which is much higher than the total storage capacity of dams constructed for flood control. Peak runoff from paddy field areas is 3 times less than peak runoff from 75 per cent urbanized areas. Several municipalities therefore subsidize paddy production. This subsidy amounts to between 20 and 80 per cent of the gross income from rice production. Total benefit from paddy fields for flood prevention is equivalent to constructing flood control dams worth 1.95 x 1012/year.

2. Groundwater recharge: Groundwater recharge is estimated at 160 x 106 m3 per day in all Japan. This supports pumping for domestic and industrial use. Benefit of groundwater recharge based on the construction of the equivalent reservoirs is estimated at ¥ 800 x 109/year.

3. Soil erosion control: 40 per cent of paddy fields are on terraced slopes. Total benefit derived from the construction of soil sedimentation dams is estimated at about ¥ 40 x 109/year.

4. Preservation of landscape and biodiversity: willingness to pay in Nara Prefecture for the preservation of paddy fields is estimated at about twice the value of gross production of paddy rice. Willingness to pay for the paddy fields in mountainous areas was 74 and 91 per cent higher than those in flat areas and suburbs, respectively.

Quoted in H. Tsutsui, Multiple Functions and Diversified Use of Paddy Fields in Japan, Proceedings of the Asian Regional Workshop on Sustainable Development of Irrigation and Drainage for Rice Paddy Fields, Tokyo, 24-28 July, Japanese National Committee of ICID.

2.7 Floods, Droughts and Climate Change10

34. Preliminary studies show that although some human systems are affected by recent increases in floods and droughts, it is difficult to quantify their relative impacts. Climatic change (global warming) is now accepted as being responsible for bringing additional risks and pressures on water resources. Increasing sea level and other extreme weather conditions damage existing infrastructure. The former is expected to rise by 15 to 95 cm by 2100 and thus extend flooding in low-lying areas. This could result in a loss of 17.5 per cent of the land area in Bangladesh. Coastal fishing and ecosystems, aquaculture and agriculture11 would suffer. Small islands would be particularly affected. Ecosystems and agricultural zones could shift towards the poles by 150 to 550 km in the mid-latitude regions. Forests, deserts, rangelands, and other natural habitats would undergo new climatic stress. Both man and nature would need to adapt to such a scenario. Total precipitation would most likely intensify, although the local level remains uncertain. The frequency and intensity of extreme weather conditions such as storms and hurricanes may change. The most vulnerable would be those who are most sensitive to them, already under stress and with the least ability to adapt. This would be the case in developing countries with weaker economies and institutions.

35. While some regions suffer from climatic extremes, others may benefit. Added heat stress, shifting monsoons and drier soil in the tropic and sub-tropic can be expected. Soil moisture is affected by changing rainfall patterns. Higher temperatures, especially if combined with water shortage may damage some crops. Arid and semi-arid conditions may become more pronounced. Rangelands may have to alter their growing seasons. Changes in the evapo-transpiration cycle in the tropics may affect productivity and the mix of species. Soil stability and hydrological systems in mountainous terrain may be affected. Climatic change also contributes to the decline of wetlands.

36. Evaporation and intense rainfall frequency would rise. Changing precipitation patterns would determine how much water could be captured and rising intensity would mean increasing floods and runoff, with possible alterations in the distribution of surface and groundwater. Reservoirs and wells would be affected. Surface changes would affect the recharging of groundwater supplies and, in the longer term, aquifers. New patterns of runoff and evaporation would also have an impact on natural ecosystems. The local hydrology becomes more sensitive as the weather gets drier. High-latitude regions may see more runoff due to greater precipitation. The effects on the tropics would be more difficult to predict. However, there is now greater confidence in the following assertions regarding changes that are currently being observed, and predictions for the future in Asia and the Pacific (Table 4):

  1. floods, droughts, forest fires, and tropical cyclones have increased temperature in tropical Asia (high confidence),
  2. decreasing agricultural productivity and aquaculture due to thermal and water stress, rising sea level, floods and other natural disasters would diminish food security in many countries (medium confidence),
  3. runoff and water availability may decrease in arid and semi-arid Asia but increase in northern Asia (medium confidence),
  4. rising sea level and intensity of tropical cyclones and rainfall would displace millions of people in low-lying coastal areas and accelerate flood risks (high confidence), and
  5. likely increase in Asian summer monsoon precipitation variability.

Table 4.
Changes in Phenomenon Induced by Climatic Change and Degree of Confidence

Confidence in Observed Changes (latter half of the 20th century)

Changes in Phenomenon

Confidence in Projected Changes (during the 21st century)


Higher max. temperature and more hot days over nearly all land areas

Very likely

Very likely

Higher min. temperatures, fewer cold and frost days over nearly all land areas

Very likely

Very likely

Reduced diurnal temperature range over most land areas

Very likely

Likely, over many northern

More intense precipitation hemisphere mid-to high latitude land areas

Very likely, over many areas

Likely, in a few areas

Increase in continental summer dryness and associated risk of drought

Likely, over most mid- latitude continental interiors

Not observed in the few

Increase in tropical cyclone analyses available peak intensities

Likely, over some areas

Insufficient data for

Increase in tropical cyclone assessment mean and peak precipitation intensities

Likely, over some areas

37. In the twentieth century, although tropical storm intensity and frequency are dominated by inter-decadal and multi-decadal variations, no significant trends were recorded. Little or small changes are expected from El Niño in the next century. Despite this, global warming is likely to lead to more pronounced dry and wet weather and the number of droughts and floods would grow in many different regions of Asia.

38. For temperate Asia, projections suggest that rainfall would increase slightly (0.5-1.0 mm/day) in the north (Siberia), and by more than 1 mm/day over the Korean peninsula, Japanese islands, and southwest China. In contrast, precipitation may decline in the northern, western, and southern parts of China. Hydrological forecasts indicate that northern China would be most vulnerable to climatic changes. During years of moderate to extremely dry weather, water deficiency may seriously aggravate any existing shortages.

39. For tropical Asia, climatic change further stresses natural resources which are already over exploited by rapid urbanization, industrialization, and economic development. This leads to increasing pollution, land degradation and other environmental problems. Substantial shifts in the ecosystems of upland tropical Asia are projected. Similarly, increases in evapo-transpiration and rainfall variability would have a negative impact on the viability of freshwater wetlands. Rising sea level and sea-surface temperature would be the most probable major climatic change for coastal ecosystems. Landward migration of mangroves and tidal wetlands would destroy infrastructure and the livelihoods of many rural households. Increasing temperature and seasonal variability in precipitation would accelerate the recession of the Himalayan glaciers and increase the danger of glacial outbursts. A reduction in the flow of snow-fed rivers, accompanied by growing peak flow and sediment, would have a major impact on hydropower generation, urban water supply and agriculture. Water availability from such rivers could increase in the short term but would lessen in the long-term. Runoff from them may alter in the future, although less water from melting snow would result in a decrease in their dry-season flow. Pressure would be most acute on drier river basins and those subjected to low seasonal flows. Hydrological changes in island and coastal drainage basins are expected to be small, apart from those associated with rising sea levels. The vulnerability of arable lands to environmental hazards, including floods, droughts and cyclones would increase. The large delta regions of Bangladesh, Myanmar, Vietnam, and Thailand, and the low-lying areas of Indonesia, the Philippines, and Malaysia would be especially threatened.

40. Communities and regions that are exposed to climatic changes are also under pressure from population growth, resource depletion, and poverty. Alleviation policies and improved management of environmental risk could help promote sustainable development and equity, enhance adaptive capacity, and reduce any vulnerability to natural calamities. Thus preparedness and planning are urgently needed with or without climatic change. Better information, stronger institutions and new technologies could minimize human and material losses. For example, buildings could be erected in such a way that damage from flood and tropical cyclone could be minimized, sophisticated irrigation systems constructed to protect farmers and their crops from drought, levees removed to help maintain floodplains, and measures instituted to protect waterside vegetation, restore river channels to their natural form, and reduce water pollution.


3.1 Agenda 21

41. The river basin (catchment or watershed) is widely accepted internationally as the natural unit for water resource management in general, and for flood and drought-related strategies and activities in particular. This is recognized by the UNCED Conference (Rio de Janeiro, 1992) in its Agenda 21, which states "integrated water resources management, including the integration of land and water-related aspects, should be carried out at the level of the catchment basin or sub-basin." The following quotes are from relevant chapters of this agenda.

  1. Chapter 10 on Integrated Approach to the Planning and Management of Land Resources upholds that "Governments at the appropriate level, with the support of regional and international organizations, should review and, if appropriate, revise planning and management systems to facilitate an integrated approach. To do this, they should adopt planning and management systems that facilitate the integration of environmental components such as air, water, land and other natural resources, using landscape ecological planning (LANDEP) or other approaches that focus on, for example, an ecosystem or a watershed".
  2. Chapter 12 on Managing Fragile Ecosystems: Combating Desertification and Drought calls for an integrated approach to the planning and management of land resources12. Action plans to combat desertification and drought should include management aspects of the environment and development, thus conforming to the approach of integrating national development plans and national environmental action plans, encouraging and promoting popular participation". (The recommended unit of intervention in Chapter 12 is not clearly stated. Grass-roots action and participation may imply that the unit may comprise a geographical area managed by a community).
  3. Chapter 14 on Promoting Sustainable Agriculture and Rural Development encourages "integrated planning at the watershed and landscape level to reduce soil loss and protect surface and groundwater resources from chemical pollution".
  4. Chapter 18 on Protection of the Quality and Supply of Freshwater Resources: Application of Integrated Approaches to the Development, Management and Use of Water Resources states that "the freshwater environment is characterized by the hydrological cycle, including floods and droughts, which in some regions have become more extreme and dramatic in their consequences Rational water utilization schemes for the development of surface and underground water-supply sources and other potential sources have to be supported by concurrent water conservation and wastage minimization measures. Priority, however, must be accorded to flood prevention and control measures, as well as sedimentation control where required. The holistic management of freshwater as a finite and vulnerable resource, and the integration of sectoral water plans and programmes within the framework of national economic and social policy, are of paramount importance. Integrated water resource management is based on the perception of water as an integral part of the ecosystem, a natural resource and a social and economic good, whose quantity and quality determine the nature of its utilization. Integrated water resource management, including the integration of land and water-related aspects, should be carried out at the level of the catchment basin or sub-basin."

42. Flood and drought management, including risk analysis and environmental and social impact assessment, are priority programme areas of Agenda 21. They include:

  1. establishing and strengthening institutional capabilities of countries and their legislative and regulatory arms to ensure adequate assessment of water resources,
  2. providing flood and drought forecasting services,
  3. reviewing and evaluating existing data-collection networks, including those providing real-time information on flood and drought forecasting, and
  4. improving data dissemination to provide forecast and warning of flood and drought to the general public and civil defence.

43. The approach prescribed in this chapter is primarily (infra-) structural, i.e., the "development and implementation of response strategies require innovative use of technological means and engineering solutions, including the installation of flood and drought warning systems and the construction of new water resource development projects such as dams, aqueducts, well fields, waste-water treatment plants, desalination works, levees, banks and drainage channels."


44. The United Nations Convention to Combat Desertification (UNCCD) in countries experiencing serious drought and/or desertification, particularly in Africa is the main instrument for international and regional cooperation on drought-related issues13. National action programmes may include some or all of the following measures to prepare for and mitigate the effects of drought14:

  1. establish and/or strengthen appropriate early warning systems at either local, national or joint levels, and take steps to assist environmentally displaced persons,
  2. strengthen drought preparedness and management, including contingency plans at all levels that take into consideration seasonal to periodic climate predictions,
  3. establish and/or strengthen appropriate food security systems, including storage and marketing facilities, particularly in rural areas,
  4. establish alternative livelihood projects that provide income in drought prone areas, and
  5. develop sustainable irrigation programmes for both crops and livestock.

45. Annex II on Regional Implementation Annex for Asia states that national action programmes shall "be an integral part of broader national policies for sustainable development of the affected country; involve affected populations, including local communities, in the elaboration, coordination and implementation of their action programmes through a locally driven consultative process, with the cooperation of local authorities and relevant national and non-governmental organizations; and, promote the integrated management of drainage basins, the conservation of soil resources, and the enhancement and efficient use of water resources; emphasize integrated local development programmes for affected areas, based on participatory mechanisms and on the integration of strategies for poverty eradication into efforts to combat desertification and mitigate the effects of drought."

46. Most countries exposed to desertification are currently preparing their national action plans and making efforts to develop regional cooperation within the framework of this convention (see Box 2). These plans follow the cardinal principles mentioned above and they have, in fact, prompted some countries to review, through a participatory process, their socio-economic policies and integrate their drought-related strategies.

47. The India report15 illustrates the gradual shift from top-down structural strategies adopted by government agencies for rural development to an integrated and coordinated approach in the area of watershed management and recovery and relief programmes to improve the resilience of communities to future calamities. Sector-based and component policies are gradually being harmonized. Reliance on indigenous technologies and traditional knowledge and practices to cope with drought is emphasized.

Box 2
UNCDD Proposals for Regional Cooperation in Drought Mitigation

The Convention to Combat Desertification in Asia (UNCCD, 2001) recommends that the plan:

  1. strengthen the knowledge base and develop information and monitoring systems for regions prone to desertification and drought, including the economic and social aspects of these ecosystems,
  2. support countries through policy research and technical assistance in their efforts to combat land degradation through intensified soil conservation, afforestation and reforestation,
  3. enhance capabilities of institutions of affected countries to develop integrated programmes to eradicate poverty and promote alternative livelihood systems,
  4. enhance governments' capacities with sectoral representation from major groups to develop comprehensive anti-desertification programmes and integrate them into national development plans and environmental planning,
  5. assist countries develop comprehensive drought preparedness and drought-relief schemes, including self-help arrangements, and formulate programmes to cope with environmental refugees, and
  6. encourage and promote popular participation and environmental education, with focus on desertification control and management of the effects of drought.

Specific projects for regional technical cooperation would include agroforestry and soil conservation, water resource management and development of early warning systems and medium-range forecasting methodologies to improve security in arid, semi-arid and dry sub-humid areas.

3.3 World Food Summit

48. More recently, the Rome Declaration on World Food Security and World Food Summit Plan of Action adopted at the World Food Summit called by FAO in 1996 included commitments by member countries to:

  1. combat environmental threats to food security, in particular, drought and desertification, pests, erosion of biological diversity, and degradation of land and aquatic-based natural resources, restore and rehabilitate the natural resource base, including water and watersheds in depleted and overexploited areas to achieve greater production;
  2. monitor and promote rehabilitation and conservation of natural resources in food producing areas as well as in adjacent forest lands, non-arable lands and watersheds, and where necessary, upgrade in a sustainable manner, the productive capacity of these resources; and establish policies that create economic and social incentives to reduce degradation;
  3. identify the potential and improve the productive use of national land and water resources for sustainable increases in food production, taking into account the anticipated impacts of climatic variability and change on rainfall and temperature patterns;
  4. develop appropriate national and regional policies and plans for water and watersheds, and water management; promote economically, socially and environmentally sound irrigation systems, in particular, small-scale irrigation, and intensify sustainable rain-fed agriculture to increase cropping, reduce the impact of droughts and floods on food output, restore natural resources and preserve the quality and availability of water for other purposes, especially human consumption;
  5. establish soonest possible prevention and preparedness strategies for countries vulnerable to emergencies.
  6. prepare and/or maintain for each LIFDC, and other countries exposed to natural calamities, information database, with an analysis of the major causes of vulnerability and their consequences, making maximum use of existing data and information systems to avoid duplication of effort;
  7. establish, maintain and promote, soonest possible, in collaboration with non-governmental and other organizations, where appropriate, preparedness strategies and mechanisms agreed upon at the ICN, including the development and application of climatic forecast information for surveillance and early-warning of natural disasters, pest and disease;
  8. support international efforts to develop and apply such information technology to improve the effectiveness and efficiency of emergency preparedness and response activities, create synergy and avoid duplication;
  9. develop such technology at appropriate community-based and regional levels; and
  10. pursue participatory and sustainable food, agricultural, fisheries, forestry and rural development policies and practices in potential areas, to ensure adequate and reliable food supplies from the household to global levels, and combat pests, drought and desertification.

3.4 Reducing Agricultural Vulnerability to Storm-Related Disasters

49. In a recent document prepared for the Sixteenth Session of the Committee on Agriculture, (held in Rome in March 2001), FAO developed strategies to reduce agricultural vulnerability to storm-related disasters. Floods caused by storms are (partially) covered by this document, which recognizes that, in Asia, severe ones recur during the monsoon and rainy seasons, often with disastrous consequences. Storm surge is the major cause of crop loss and in India, it accounts for more than 90 per cent of loss to life and property.

50. Factors that determine storms and floods are the water level, topography, soil types, their moisture, depth, holding and drainage capacity, land use and farming practices that influence their organic matter content and permeability. Improvements such as levelling, terracing and irrigation are other practices used to manage water flow and hold soil in place during storms and floods. Deep rooting plant such as shrub and trees can also be grown to provide more stability.

51. This paper highlights the need for a strategy to reduce agricultural vulnerability to tropical storms as the economic cost of crop and infrastructure loss may represent a substantial dent on the GDP of affected countries. This calls for a framework to intimately link disaster management schemes with long-term development programmes to prevent their retardation, loss of productive investments, protect the standard of living of affected communities, and whenever necessary, divert resources from such programmes to rehabilitate disaster-affected communities. The objectives are to avoid or minimize the risk of death, injury and suffering to people, prevent the poor from getting poorer, reduce unforeseen large-scale relief and rehabilitation expenditures, minimize disruption of the development process and ensure its sustainability with effective poverty eradication programmes by lessening the vulnerability of communities to storm disasters. Such a strategy should include long-term measures, properly integrated overall development programmes for storm and flood-prone areas and for the country as a whole, early warning and storm forecasting systems and a preparedness and rehabilitation plan in the event of such disasters, linked, where possible, to the long-term programmes. To reduce vulnerability to floods and tidal waves, land-use, agricultural, forestry and fisheries planning could incorporate more resistant crops, diversify cropping systems that offer insurance against loss, establish forestry shelterbelts and tree and grass species to stabilize slopes, maintain mangrove swamps as buffer zones, conserve soil and water, and construct drainage works, windbreaks small-scale embankments, dams and canals to protect roads, settlements and arable and grazing land.

52. Intervention should be integrated and consistent at all levels, from the farm to the central government. It is necessary to involve farmers and incorporate local technology. FAO's approach to disaster management is based on two overriding principles. One is to make communities resilient to the effects of all kinds of hazards, to reduce the compound risks they pose to modern society, and the other is to move from protection to the management of dangers by incorporating preventive measures into sustainable development. Risk assessment studies could characterize the nature of storm-related risks in vulnerable zones, and identify the steps that could be taken to mitigate them, including improved watershed management and appropriate land use.

3.5 World Commission on Dams

53. This Commission, in its final document,16 examined the role of dams in flood management and noted that the growing concern over their cost has led to support for the integrated management of floods rather than their control.17 Large dams have, however, been very effective in the case of Japan. It is difficult to fully control floods and manage their relationship with people. Therefore, it has become necessary to shift the emphasis to integrated flood management, i.e., to set objectives in term of predicting, managing and responding to them, rather than simply controlling them.

54. Such management is essentially catchment-based, where the scale of flooding would be reduced by a number of structural and non-structural methods. The former includes building infiltration and retention ponds and trenches, detention basins, and wetland areas to reduce runoff; protecting forests by reducing logging and clearing, scaling down agriculture to minimize soil erosion, landslides and channel silting; improving small-scale storage of runoff; increasing people's coping capacities; integrating catchment and coastal zone management; instituting wise planning and zoning of floodplains and coastal areas; allowing local communities to make choices on land development and flood alleviation; and reducing the impact of humans on the environment by promoting flood disaster resilience. The latter includes preserving the best local technology and improving local capacity to respond; and addressing the problems of equity by, for example, alleviating poverty and lack of access to resources as a means of addressing flood vulnerability.

55. The key conditions to developing and sustaining such management strategies lie in promoting public involvement, flood hazard management and emergency response agencies and devolving decision-making to the lowest level; giving a multi-functional approach to intervention funding, practicing institutional design; and encouraging local ownership of flood alleviation strategies and options for long-term success. The World Commission on Dams has given an excellent review on flood management options.18


56. The Economic and Social Commission of the United Nations (ESCAP) established a bureau for flood control in 1949 (currently the Water and Mineral Resources Section). Flood management is a priority area of work for ESCAP, as seen from the number of technical projects and publications on it. Recent ones provide valuable insights and guidelines on the evolution of concepts and their implementation in the region19.

57. The guidelines also deal with the institutional, legal, public, human and natural aspects of water management, and the prime responsibility of the government to safeguard policies that support them. They recommend that national, state and/or regional policies should be developed for each major category of natural resource, i.e., land-use, soil, vegetation, surface water, groundwater and vegetation-management and they should be integrated.

58. ESCAP (1999) maintained that flood management of Asia's river basins should be made part and parcel of national development objectives. In fact, they have in recent times, become a foundation for socio-economic development, e.g., Australia's upper Parramatta river catchment, Malaysia's Klang river basin, Indonesia's Brantas and Citarum river basins, Republic of Korea's Keum river basin and Japan's Tone-Edo river basin, etc. Flood control can also be considered as the social component of national economic development, especially where its cost is too high compared to annual government budgets or allocations for public sector investment. According priority to reducing disasters is a difficult task in the context of the national development process. This is the case for Bangladesh. Its 1995 water and flood management strategy illustrates how government policy evolved gradually over the last 30 years from a narrow focus on flood control to a wider context of flood and water management in the context of overall national goals. This strategy reflects the embodiment of cross-sectoral issues, environmental concerns and public opinion.

59. Emerging flood control management trends in the region focus on comprehensive basin management, accelerated by the shrinking of many urban catchments where land use on their upper areas can exert a major influence on floods. Control measures imposed on one part of a basin can have a significant impact on the other, thus making its spatial aspects much more important. Such trends also emphasize more effective storm-water management in urban areas based on a participatory and integrated approach, efficient river administration to balance the safety level between different areas, effective enforcement of land-use regulations, cooperation between upstream and downstream areas, reconciling technical requirements for flood protection and environmental enhancement, and implementing the best methods for flood diversion channels especially during the dry season. The overall assessment of achievements in the region is that although floods remain common, frequent and severe, national authorities have established various structural and non-structural measures, including land-use guidelines and zoning, disaster-prone and risk mapping and warning systems to overcome them.

60. ESCAP noted a marked increase in awareness of the importance of disaster preparedness and in government commitments to reduce disasters in a number of countries, where infrastructure to ensure the effective mobilization of resources and sustained public participation in national efforts have been created, and national coordination committees, management systems, programmes and action plans have been established. The future of flood management is geared towards strategic control underpinned by long-term visions and objectives to be shared by all stakeholders.

3.7 FAO-ESCAP Project

61. The Vision for Food and Rural Development, prepared under the aegis of the World Water Council and presented at the Second World Water Forum (Hague, 2000), called for more investment in integrated water resources management to benefit the living environment, production base and people's livelihood, with the active participation of rural communities within the catchment unit. The vision underlined the potential for alleviating poor communities by helping them manage water stress. Farmers around the world have developed systems to `harvest' rainfall but there is great scope to improve them by on-farm water management, such as the adoption of both `low-tech' (traditional) and `high-tech' (modern) measures such as drip irrigation. This is also the case in semi-arid areas, where additional institutional steps could be taken to help poor farmers survive droughts, and recover from them. Crop insurance, employment and other assistance schemes are options that help recover productive assets lost during a drought. In wetter areas, focus on integrated environmental management together with flood control, drainage, soil and water conservation and afforestation can assist all farmers produce more and withstand natural disasters better.

62. The Vision also indicated that water for food production competes with other uses. The higher its usage and scarcity, the more urgent the need to integrate its management. An organization is required to allocate its use, optimise its productivity and reduce competition between the various consumers and stakeholders. This would need the establishment or amendment of rules on usage, quantity and quality standards and involve co-ordination, planning decision-making, policing and control of both surface and sub-surface water pollution. This body should be under the government, have legal powers in order to protect the interest of the majority and be able to function at the sub-basin level. It should also have a clear regulatory framework with norms and standards for decision-making, a system to provide reliable information, be effective and transparent, with powers to control and sanction violations and adequate capable personnel to meet the desired goals. The Vision also called for the creation of new rural institutions for water management and poverty alleviation, such as groundwater marketing groups20 or new catchment organizations21.

63. A global Vision was also formulated based on sectors, general consultations and regional, sub-regional and national visions developed under the aegis of the technical advisory committees of the Global Water Partnership. They are important for future planning, as they reflect the consensus achieved by authorities, professionals and NGOs. This consensus is particularly firm on the principles of river basin management to contain floods and droughts. The regional and national visions take into account the findings of studies made at the global level, for instance on technology, bio-technology, new plant varieties and drought, salt- and flood-resistant crops.

3.7.1 Vision for South-East Asia 22

64. Here, the aim is to sustain water resources to ensure adequate quantity and acceptable quality to meet the needs of the country in terms of health, food security, economic prosperity and the environment. It embodies access to safe and affordable supplies for hygienic and sanitation purposes, and is meant to motivate all regional economies to protect their valuable resource. To achieve this, there is a need to move towards integrated river basin management and promote equitable sharing among users and the environment. The former is regarded as the ideal venue to attain such equitability as all types of users operate within the same arena. In addition to this role, the management should lead in mitigating water-related hazards and erosion, and maintain a certain degree of ecological balance. The development of a well-informed and motivated population who understands the complex nature of water resources management is important. Thus, for the present, the central goal is to focus on people's participation, with special attention on the poor, women and children who are most affected by water shortage, pollution and floods.

3.7.2 Vision for South Asia 23

65. The Vision in this region is to alleviate poverty and raise living standards, health and well-being of the entire population to sustainable levels through coordinated and integrated development and management of water resources. When achieved, it would have fostered a gender balanced social, economic, environmental and cultural life. A basin-oriented management approach including a regional body to co-operate on water resources planning and management is envisaged. At the national level, basin and irrigation organizations should be multi-disciplinary in character and focus on integrated water and land resources management where all stakeholders; local, national and regional, can participate with transparency and accountability. Women should be allowed to play a key role.

66. The Vision points out the lack of consensus between the pro-dam and anti-dam forces, although it argues that dams can be beneficial for hydro-power, irrigation, flood control, navigation and low-flow augmentation purposes in the dry season. They improve water quality by pushing saline intrusion downstream. The Vision supports the use of indigenous knowledge and traditional water harnessing technologies in management, but they should not be pitted as alternatives to large storage. It recognizes the river basin as a unit for resource planning, ecosystem and environmental sustenance, watershed conservation, and quality management of surface and groundwater. Flood protection should be dealt with at a regional level in cases where rivers flow across national boundaries, ecosystem24 and environmental demands met through allocation, and institutions created for planning and management purposes. It stresses population growth, poverty eradication, food storage and environmental concerns as key issues in management planning.25

3.8 FAO-ESCAP Pilot Project 26

67. This project, initiated in 2000 is aimed at complementing global and regional visions by assisting four countries in South-East Asia, namely, Malaysia, Thailand, Philippines and Vietnam adopt their national visions and develop priority areas through strategic planning techniques. This will form the basis for developing wider regional cooperation on water resources management. Water-related disaster mitigation is a major issue for the present and the future. Country versions are given below.

3.8.1 Thailand

68. The National Water Resources Committee in its 20 July 2000 meeting endorsed Thailand's Vision. The recommended policies are as follows:

  1. create water management organizations at both national and river basin levels with supportive laws, with the former responsible for formulating national policies, monitoring and coordinating activities to achieve the set policies, while the latter prepares participatory management plans;
  2. emphasize suitable and equitable water allocation for all sectors to achieve basic agriculture and domestic requirements by establishing efficient and sustainable individual basin priorities under clear allocation criteria and incorporating cost sharing based on ability to pay and level of service;
  3. identify clearly the role of non-government and government organizations in efficient management that covers utilization, source conservation and monitoring of quality; and
  4. accelerate preparation of plans for flood and drought protection, damage control and rehabilitation efficiently, with proper utilization of land and other natural resources.
3.8.2 Philippines

69. In the case of the Philippines, the Vision for the 21st century (Plan 21) is to create a modern and humane society, raise the quality of life of all Filipinos and bequeath the society in an ecologically healthy state to future generations. This embodies sustainable water resources management to provide affordable and adequate needs and proper disposal. The statement for the water sector reads as follows: "By the year 2025, water resources in the Philippines are being used efficiently, allocated equitably and managed sustainably with provision for water-related disasters".

70. The major components of water management are presently vested in several government agencies (over 30 of them) that undertake most of the water projects in the country. Each of them is, by tradition, responsible for certain aspects of water resource development. They are separate agencies dealing mainly with individual sectors such as supply, irrigation, hydropower, flood control, pollution, watershed management, etc. Each undertakes programmes exclusively within its own field of responsibility. Project identification and planning are performed to meet the targets of the agency with little or no regard for the needs of others.

71. The Vision's first priority is to integrate river basin management and increase the number of authorities from 2 to 18 by the year 2025. It also envisages a legal and institutional framework for capacity building and establishing strategic and operational plans to ensure a sustainable environment, and socially equitable and economically efficient water allocation among stakeholders. It seeks alternatives to alleviate water conflicts, maximize its productivity, mitigate any adverse environmental impact and water-related hazards, maintain ecological balance and rehabilitate rivers.

72. One of the major components of its action programme is to control flooding to tolerable levels in Metro Manila and other major cities, provide adequate drainage facilities in all flood-prone areas, and coordinate the development of irrigation schemes and water impounding dams to lessen flood damage and increase the production of rice and other crops. It views the cooperation with relevant government agencies as necessary to comprehensively plan for river basin management whose responsibility includes erecting control structures, practicing reforestation, relocating and preventing squatters from living along river banks, controlling lahar, dredging and silting, establishing and maintaining viable and effective garbage collection and disposal systems for areas that use rivers/waterways for drainage, and organize brigades and campaigns on disaster preparation.

Box 3
Agno River Basin Development Commission

The Agno River Basin Development Commission is mandated to oversee and coordinate all development along this river and to ensure a holistic approach towards its water resources planning and management. Its functions are to:

  1. develop a comprehensive master plan for the river basin,
  2. integrate this plan with local and regional plans and investment programmes,
  3. implement development projects related to the basin,
  4. initiate, receive and recommend project proposals for the basin's development,
  5. formulate, review and propose improvements in existing policies governing the basin's development,
  6. commission, coordinate, monitor all planning studies and research and development in the basin;
  7. coordinate preventive measures and other projects among concerned government agencies,
  8. establish a functional information and database system including computer generated planning tools such as GIS.

The programmes/projects/activities of the Commission are as follows:

  1. formulation of the Agno Rriver basin master plan,
  2. coordination and implementation of development programmes and projects,
  3. project monitoring and evaluation,
  4. development of studies for planning and decision making,
  5. information and database management for planning and policy decision making,
  6. social marketing,
  7. resource generation and investment programming and marketing, and
  8. institutional and staff development.
3.8.3 Vietnam

73. The Red River delta had an old and vulnerable system of earth dikes that were breached by severe floods in 1945, causing deep inundation of more than 260,000 ha of paddy field. This, together with the war brought extensive damage to crops and resulted in widespread and serious famine that claimed more than 2 million lives. Since then, the government has consistently spent much of its capital resources and mobilized the people to recover from the terrible loss by restoring water control structures and strengthening flood protection dikes. This priority has been maintained in its various 5-year national plans. The Mekong River delta has several navigation channels excavated during the same period for the transport of goods, while crop cultivation relied totally on rainwater in the absence of water control structures. In the central region, highlands and mountainous areas, droughts are a regular occurrence.

74. In spite of massive efforts made to contain natural disasters, flooding in the Red River in 1995 continued to threaten sustainable development of its delta, with dire consequences on agricultural production and the whole economy. A need still exists to invest in infrastructure development, to combine water resources protection plans of the Red River delta with those of the Lo Gam and Da rivers, and to practice proper reforestation and forest protection.

75. Ecological changes and water use at the source complicates the Mekong's flow during the dry and rainy seasons. While the influx of saltwater is widening, that of freshwater is narrowing, at a time when the demand for water in the dry season is increasing. Therefore, the urgent task is to build dykes, drains, etc. to prevent saltwater incursion. Besides agricultural development, industrialization of the Mekong River delta created a greater demand for water. While flooding of this river brings problems to its inhabitants, particularly those in newly developed areas where suitable housing is absent, it provides alluvial materials for soil fertility, and decreases the incidence of pests. This indicates a need to work out different sustainable strategies to meet the different needs of different regions. It also complicates distribution and management arising from the multiplicity of needs, to supply and save water in the dry season, prevent flooding in the rainy season, preserve the environment, treat agricultural and industrial waste and simultaneously deal with water-related issues consistently.

76. Besides prevailing problems, Vietnam expects water-related hazards such as severe storms to increase in frequency by 0.6 storm for each decade, and typhoons to raise the water level by 2 meters and account for 11 per cent of total storms. The sea level is predicted to increase by 0.2 cm annually, while coastal erosion and landslides are anticipated to intensify in terms of both number and strength. Daily rainfall is increasing by 500 to 700 mm or more. In internal areas such as Lai Chau and Konntum, it exceeds 300 mm. Decreasing forest areas results in more serious flooding. Flash floods also occur more often in many places, particularly in small basins. However, without any hydrological records, it is difficult to give exact calculations. The water flow in the dry season is narrowing due to decreasing rainfall, forest fires, deforestation and over exploitation of water sources. Shortage begins in February or March, which is one to two months earlier than previously.

77. Given the above scenario, the Vietnam Water Vision envisages an integrated and sustainable use of water resources and the provision of clean water for food and socio-economic development, preservation of water eco-systems, prevention and mitigation of its harmful effects and the maintenance of a reasonable pricing system. It foresees nationwide cooperation to achieve efficient and effective management, and international cooperation on shared river systems for mutual benefits.

Box 4
Implementation of the Red River Basin Vision

The March 2000 Hanoi Round Table on Water Vision made the following proposals:

  1. clean water, green land and a prosperous people,
  2. establish a Red River Basin Commission as agencies presently responsible for management of river basin water resources are fragmented among many bodies, provincial authorities and civic groups,
  3. consolidate all plans (sector and local) into an integrated basin plan for sustainable development, disseminate it to all stakeholders, and mobilize and encourage their participation in its implementation, and
  4. take priority actions to create an integrated master plan, establish a management body for the basin's water resources within a suitable legal and institutional framework, popularise this plan, promote better control and mitigation of water-related disasters, particularly floods, enhance management role of government agencies to improve interaction between sectors and with the people, and increase public awareness of the "clean water and green land" concept and seek their involvement.
3.8.4 Malaysia

78. The Vision 2020 adopted by Malaysia no longer views water shortage as an issue because most flooding in the country has been mitigated through both structural and non-structural means, except in extreme cases of monsoon floods for which early warning systems and flood fighting and rescue measures are in place. In support of Vision 2020 which is to achieve developed nation status, Malaysia is conserving and managing its water resources to ensure adequate and safe supply for all (including the environment). The key objectives of this Vision are access to safe, adequate and affordable water supply to everyone, provision of sufficient amounts to ensure national food security and promote rural development, sustain economic growth within the context of knowledge based economy and e-commerce and protect the environment by preserving water resources (both surface and groundwater), natural flow regimes, biodiversity and cultural heritage as well as mitigate water related hazards.

79. Certain parts of the country experience floods even during times of water shortage.27 This is caused by excess rainwater running into streams and rivers and uncontrolled development in watershed areas and along river corridors. Excessive river sedimentation adversely affects drainage and leads to more frequent and intense flooding downstream. Flash floods are on the rise in urban centers due to the runoff characteristics of built-up areas. Absolute control is physically and economically impossible. However, mitigation measures, consistent with the cost involved, are being taken to reduce damage to a minimum. Besides the construction of dams and reservoirs and the improvement of river systems, steps to increase infiltration and/or to store excess water in small ponds and retention basins are being taken. The Drainage and Irrigation Department is producing a Storm Water Management Manual to address the incidence of flash floods in urban areas. The set of initiatives required to achieve the key objectives of the Vision is based on four challenges towards a better water future, that is, managing water resources efficiently and effectively (addressing both quantity and quality aspects), moving towards integrated river basin management, translating awareness to political will and capacities and moving towards adequate (safe) and affordable water services (befitting a developed nation status by 2020).

80. The move towards a better water future, besides being based on these four challenges, also sets out to attain certain targets that relate to the institutional and legal aspects of integrated water management, participatory approach to decision-making, development of new/innovative technologies, efficient use of water resources, extensive research and development, shift from water supply to water demand management, establishment of river basin organizations, promoting awareness, education, good databases and networking in the water sector, timely information dissemination, resource assessment, monitoring, ecosystems protection, flood and drought contingency plans, water quality management, frequent dialogue with stakeholders, water sector master plan and formation of a national water institute. The technologies that impinge on the water sector relate to its use and distribution, pollution, selection of drought-, pest- and salt-resistant crops that are expected to reduce its use, and subsequently, enhance supply availability by means of recycling and the application of renewable energies in this sector.

3.9 Joint Initiative of Mekong River Commission and FAO28

81. In 1995, '96 and `97 heavy tropical storms and typhoons originating from the China Sea, caused disastrous flooding in Lao, Cambodia, Thailand and Vietnam. In Lao, about 24,000 ha of cropped land were flooded in 1994, 87,000 ha in 1995, and 76,000 ha in 1996. In 1996, 450,000 ha were flooded in Cambodia and heavy casualties occurred in the Mekong delta in Vietnam. FAO provided technical assistance to Lao PDR in 1996-1998,29 with the objectives of developing a better understanding of the dynamics of flooding, defining options for food loss prevention and formulating a strategy for flood management for its vulnerable agricultural sector.

82. The Mekong River Commission Secretariat (MRCS) is primarily responsible for planning and coordinating flood management. It cooperated with FAO in organizing a regional workshop on flood management and mitigation in the Mekong River Basin in Vientiane in March 1998. This workshop recommended the need for greater regional cooperation and for adequate technical support and resources among national governments. The Secretariat's role is essential and its capacities require strengthening, in particular, to introduce technologically advanced techniques in flood monitoring and forecasting.

83. To overcome existing problems, it recommended identifying, classifying and mapping areas that are subject to flooding for purposes of preparedness and management. The potential offered by remote sensing to monitor and identify rapidly inundated areas and the use of GIS techniques to make inventories and analyse more systematically the impact of floods on agriculture and infrastructure should be explored. It was recognized that there was an urgent necessity to make flood management an integrated part of reservoir operation for hydropower, and that flood control works could offer more lasting solutions to flood management. Thus greater local awareness and preparedness in relief, mitigation and management is required, with proper institutional capacity at all levels to address water problems on a continuous basis, besides examining the potential to promote dry season irrigation to offset yield reduction due to flooding.

84. The following solutions at different levels and in different sectors were identified:

  1. survey and monitor flood prone areas to effectively mitigate floods, classify their depth and frequency and prepare for emergency measures to reduce or overcome damage caused by exceptional ones,
  2. forecast and monitor on a regional basis,
  3. institute proper reservoir management to optimise storage and energy production,
  4. invest in control works, e.g.,30 flood gates and protection dikes and make local and national investment studies to assess effectiveness of such measures taken, and provide a basis to prioritise essential investments to rehabilitate and construct flood control and water management infrastructure,
  5. build local awareness and preparedness at district and village levels, encourage cooperation in implementing self-help projects and making use of traditional technologies to find the most cost effective and sustainable technologies,
  6. diversify agricultural production and extend production basis of irrigated crops during dry season to compensate for recurrent losses due to floods,
  7. implement appropriate and adequate national and local mechanisms and capacity to cope with emergences and plan for long-term solutions, and
  8. establish a national flood management unit to consolidate strategies that include assessment, classification, monitoring, planning, etc. to contain flood damage.

Box 5
Detailed Recommendations of the Vientiane
Workshop on Flood Mitigation

Flood Surveys:

  1. integrate approach to data collection and management taking into account ground and satellite based technology,
  2. evaluate alternative procedures using remote sensing technologies, incorporating the hydrometric network and hydrodynamic studies,
  3. institute joint plan of action among regional pilot projects,
  4. practice real time reception of meteorological satellite data,
  5. promote national capacities for processing and use of flood data, and
  6. encourage further regional cooperation.

Flood Forecasting and River Modelling:

  1. modernize present flood forecasting system of MRCS with new components such as pattern recognition techniques to process rainfall forecasts, distributed hydrological modelling, hydrodynamic and flow modelling etc.,
  2. include the great lake area of Cambodia and the Mekong delta in Vietnam,
  3. exchange information and data transfer between regional and national centres,
  4. reinforce centres, and
  5. adopt a consistent and harmonized line of software for database management, simulation modelling and water resources planning.

For Lao:

  1. study flood phenomena on the Vientiane plain,
  2. operate reservoirs on a multipurpose basis,
  3. implement flood protection schemes based on typographic data and time dependent hydrologic simulation, and
  4. use differential GPS for topographic mapping.

Flood Control Works:

  1. make additional studies to assess potential and feasibility of flood protection works, taking into account increased agricultural production from flood protection measures and irrigation, safety of human lives and possible impact on environment,
  2. ensure accuracy of topographical data base,
  3. strengthen local capacity in planning and implementation, including training of national and local technical staff for feasibility studies on flood control work and provision of support to local communities, and
  4. develop a national framework for integrated water resources management, with adequate attention on a national water sector profile, including important potential flood control works, to ensure adequate investment and resources in this sector.

Local Preparedness in Flood Control:

  1. develop awareness and preparedness in cooperation with local communities,
  2. plan community involvement to increase awareness and willingness to participate,
  3. furnish adequate technical and financial support,
  4. train provincial and district staff, and
  5. implement simple, low-cost irrigation technologies.

National Flood Management Action Plan:

  1. develop a national flood management action plan, in each of the riparian countries of the Mekong river, which defines the strategies and priorities adopted, promote investment, capacity building and training at all levels, ensure cooperation between national agencies and ministries and coordinate regional cooperation and support, and
  2. reinforce flood management unit to define flood mitigation measures, monitor annual floods and create national and local preparedness for floods.

* Researched and prepared by Thierry Facon, RAP Regional Water Management Officer.

1 The Report on sector consultation regarding "water in rivers" mentioned that the problem occurs even in receding rivers and associated ecological and quality disasters. The Huanghe or Yellow River did not reach the sea for some days in 1972, and in 1997, it failed to reach the sea for a total of 7 months during the entire year.

2 Green, Parker and Tunstall, 2000.

3 Recession agriculture is practiced between irrigated and rain-fed agriculture. Crops are planted after peak flows on a river or lake and when the soil is fully saturated. Planting schedules fit in with the water line movement and rely on residual water stored in the soil. Recession agriculture also benefits from the natural fertility of sediments deposited by the receding water. This technique does not require any infrastructure or management except the need to allocate the limited foreshore land to cultivators. However, if the normal flood does not occur due to late rains, drought or excessive inundation, large areas cannot be harvested and food shortages and famines may occur. Such agriculture can still be found on the margins of many lakes and rivers in Asia. Its potential for improved food supplies and incomes is largely localized.

4 Crop production potential may be lowered if the deposits are rather infertile and comprise drought prone sandy matter or silt which may initially be saturated.

5 The last two are caused by other than climatic factors.

6 It has been argued that those most exposed to food shortage tend to be located in conflict zones, where food cannot reach them. Weather and hazardous climatic or environmental conditions are less important than politics influencing food production and distribution. The economic, social, and cultural framework (what policy makers increasingly term "the enabling environment") would be paramount to prevent natural elements from precipitating wider disasters. This opinion stems from the observation that, despite the seemingly arbitrary nature of sudden natural disasters, they do not affect all areas in the same way, even when their severity is of a similar scale. Healthy economies rapidly bounce back from shocks because they have more internal resources dedicated to mitigating the immediate and longer-term impacts on food production or distribution. Similarly, precautions that minimize the impact of disasters, such as earthquake-resistant housing and roads, are not distributed evenly either across or within countries. Some so-called "natural" disasters might be better thought of as man made. Sudden natural disasters cannot be prevented, but the effects that they have on food production and food importation are conditioned more by political and economic processes than by the intensity of the calamity (Mainguet, 1995).

7 The upper half corresponds to the northern hemisphere winter and the lower half covers impacts during April to September. D: drought; R: unusually high rainfall; W: abnormally warm periods.

8 Greene, Parker and Tunstall, 2000.

9 Greene, Parker and Tunstall, 2000.

10 Information in this section is quoted from the following documents of the United Nations Environmental Programme (UNEP) and especially from the Inter-Governmental Panel on Climate Change (IPCC): Climate Change Information Sheets, July 1999; IPCC Working Group I, Third Assessment Report: Summary for Policymakers, January 2001; IPCC Working Group II, Third Assessment Report. Draft. February 2001; IPCC Working Group III, Final Draft Summary for Policymakers, Climate Change 2001, Impacts, Adaptation and Vulnerability, February 2; The Regional Impacts of Climate Change, 2000.

11 Coastal aquifers may also be damaged as salty groundwater rises.

12 Main activities envisaged are:

  1. combat land degradation through intensified soil conservation, afforestation and reforestation,
  2. develop and strengthen integrated development programmes to eradicate poverty and promote alternative livelihood systems in areas prone to desertification,
  3. develop comprehensive anti-desertification programmes and integrate them into national development plans and environmental planning,
  4. develop comprehensive drought preparedness and relief schemes, including self-help arrangements to cope with environmental refugees, and
  5. promote popular participation and environmental education, with focus on desertification control and management.

13 UNCCD proposes the following definitions: "drought" means the naturally occurring phenomenon that exists when precipitation has been significantly below normal recorded levels, causing serious hydrological imbalances that adversely affect land resource production systems; "mitigating the effects of drought" means activities related to the prediction of drought, and intended to reduce the vulnerability of society and natural systems to drought as it relates to combating desertification.

14 Priority fields identified for action are: promotion of alternative livelihoods and improvement of national economic environments with a view to strengthening programmes aimed at the eradication of poverty and at ensuring food security; demographic dynamics; sustainable management of natural resources; sustainable agricultural practices; development and efficient use of various energy sources; institutional and legal frameworks; strengthening of capabilities for assessment and systematic observation, including hydrological and meteorological services, and capacity building, education and public awareness.

15 Government of India. Ministry of Environment and Forestry. 2000. National Report on Implementation of United Nations Convention to Combat Desertification. New Delhi.

16 Dams and Development: A New Framework for Decision-Making, November 2000.

17 Dams have encouraged settlement in flood prone areas. The cost of ensuring complete protection against all floods is exceptionally high. The effectiveness of structural measures is reduced over time due to the accumulation of sediment in riverbeds and reservoirs. Floods have many beneficial uses in different river basins and the elimination or reduction of natural flooding has led to the loss of important downstream ecosystem functions, as well as the livelihood for flood-dependent communities.

18 Green, C.H., Parker, D.G. and Tunstall, S.M. 2000. World Commission on Dams, Thematic Reviews Option Assessment: IV, Assessment of Flood Control and Management Options. Available at

19 Manual and Guidelines for Comprehensive Flood Loss Prevention and Management, 1991. Guidelines and Manual on Land-Use Planning and Practices in Watershed Management and Disaster Reduction, 1997, and Regional Cooperation in the Twenty-First Century on Flood Control and Management in Asia and the Pacific, 1999.

20 Irrigation systems can be developed and managed by the land poor if they are given opportunities to become water sellers. Competitive water markets that give choices to water buyers can help the poor, but this requires flexible legal arrangements that allow companies to amend their activities to help the growth of new water supply services. The long-term prognosis for competitive and affordable groundwater markets that help the poor faces uncertainty, unless public action can regulate groundwater use and energy supply in ways that complement sustainable use and equitable access.

21 In many countries, catchment-level councils are being established to negotiate water rights and responsibilities across competing sectors within the hydrographic unit of the catchment.

22 Southeast Asia Technical Advisory Committee of the Global Water Partnership, Second World Water Forum. 2000. Vision to Action Report, South Asia. Hague.

23 Southeast Asia Technical Advisory Committee of the Global Water Partnership, Second World Water Forum. 2000. Vision to Action Report, South Asia. Hague.

24 Allocation of water to meet the needs of ecosystems, watershed development, afforestation; protection for aquatic resources and mangroves, etc.

25 Even so, not every country is expected to be self-sufficient, although it is hoped that the region as a whole could remain self-sufficient. Pakistan expects a shortfall of 28 million tons in production of all major food grains and crops by 2025.

26 Le Huu Ti and Facon, T. 2001. The FAO-ESCAP Pilot Project on National Water Visions: Synthesis of Experiences in South-East Asia, FAO-RAP.

27 High rainfall during monsoon periods floods large areas of the country. About 29,000 km2 or 9 per cent of the total land area in Malaysia is flood prone and this affects some 12 per cent of the population. The average annual flood damage has been estimated at RM 100 million (at 1980 prices) but this has increased due to urban expansion and the escalation of land and property values.

28 RAP Publication 1999/14. Flood Management and Mitigation in the Mekong River Basin. FAO, MRC Department of Irrigation, Ministry of Agriculture and Forestry of Lao PDR Proceeding of the Regional Workshop, Vientiane, 19-21 March 1998. FAO, Bangkok.

29 Flood loss prevention and flood management plan for the agricultural sector, TCP/LAO/6613.

30 Important potential control works to reduce destruction and provide a more permanent solution to recurrent floods are: control gates to prevent back-up of high floodwater; control dams and retention dikes to protect urban areas and agricultural lands; widening and deepening tributaries and natural drains; diverting channels and retarding basins to divert floods to pre-designed wetlands where habitation and agricultural activities are absent.

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