9 Climate Change and Water Resources Management in Bangladesh 9.1 INTRODUCTION 9.1.1 LOCATION Geologically major part of Bangladesh is occupied by one of the largest deltas of the world, formed by the Ganges-Brahmaputra-Meghna River system (Fig. 9.1). The quaternary deposits cover more than 85% of the country and the rest is by the folded tertiary sedimentary rocks. Unique geographic and tectonic position and geomorphologic conditions have made Bangladesh meeting place of natural hazards especially most vulnerable to climate change and sea level rise (SLR). Himalayas in the North, close to the subduction zone and Bay of Bengal in the South have made Bangladesh vulnerable to climate changes. Cyclones, storm-surges, floods, droughts, river and coastal erosion, are common in Bangladesh (Alam, 1997). Some part of the country is within the seismic zone. The country has a very low and flat topography, except the Northeast and Southwest regions. It is almost entirely an alluvial deltaic plain with hills on the Northeast coast and Southeast margins. About 10% of the country covering 14,000 km 2 is hardly 1 m above the mean sea level (MSL). One-third of Bangladesh is under tidal influence. Generally Bangladesh is blessed with a sub-tropical monsoon climate. There are three prominent seasons in a year namely winter, summer (pre-monsoon) and monsoon. Winter, which is quite pleasant, begins in November and ends in February. Usually in winter there is not much fluctuation in temperature. The normal winter temperature ranges from a minimum of 7°C to a maximum of 31°C. The winter season receives a negligible amount of rainfall and is characterized by low temperature, low humidity and high solar radiation. The summer begins from March through May, with a mean temperature of about 30°C and occasionally a rise above 40°C. The hot summer (pre-monsoon) season receives some rainfall in occasional heavy thunderstorms and hailstorms. The summer is characterized by its highest temperature and evaporation rates. The monsoon (rainy) season begins in June HOSSAIN SHAHID MOZADDAD FARUQUE 1 MD. LIAKATH ALI 2 1 Director General, Water Resources Planning Organization (WARPO), Ministry of Water Resources, Government of Bangladesh. 2 Senior National Expert, Program Development Office for Integrated Coastal Zone Management Plan. Copyright © 2005 Taylor & Francis Group plc, London, UK and continues up to October with maximum temperature usually around 30°C with high humidity and low solar radiation. Mean annual temperature throughout the country is about 26°C but extreme temperatures range from about 5°C to about 43°C (Bangladesh National Committee of the International Commission on Irrigation and Drainage, 1995). The average overall annual rainfall is about 2,300 mm. About 81% of the rainfall in Bangladesh occurs in the wet monsoon period (June-September) (BANCID, 1995). Fig. 9.1 Location and major river basins of Bangladesh. The major water related problems of the country are - floods, droughts, river erosion, land degradation, arsenic contamination in ground water, river sedimentation, low flow in rivers, cyclone, storm-surges, river pollution, etc. To support its agro-economy Bangladesh, ensuring people’s safety and mitigating economic damage, in the past water resources development was focused on flood control, drainage and irrigation activities. 9.2 WATER RESOURCES PROBLEMS AND THEIR MANAGEMENT 9.2.1 FLOODS Almost every year floods occur in Bangladesh. But the intensity and the magnitude of the floods vary from year to year. In some years, floods occur locally and in others it encompasses vast areas of the country. Floods of 1987, 1988 and 1998 were extensive in a real extent and colossal in terms of destruction (Mirza, 2003). As much as three-fourths of the country was affected in 1998. Floods cause enormous economic loss to the country destroying its infrastructures, standing crops, livestock and also human lives. Natural floods: About one-fifth to one-third of the country is flooded to varying degrees each year during June through September when about two-thirds of the food grain (mainly rice) are produced. The following natural floods are encountered: • River flood; • Rainfall flood; • Flash flood; • Tidal flood; • Storm-surge flood. Farakka Barrage Commissioned 1975 BASIN BASIN BASIN 232 WATER RESOURCES MANAGEMENT IN BANGLADESH Copyright © 2005 Taylor & Francis Group plc, London, UK Table 9.1 shows the flooded area of Bangladesh for different return periods. The available flood damage information is not always complete. Flood damage assessments are generally prepared by various organizations, which are often not systematic and well coordinated. There is a need for a unified and consistent method of collecting data. One of the best available sources of flood damage information is the Ministry of Disaster Management and Relief. The assessments by various institutions are compiled together into an overall flood damage assessment. The flood control embankment itself suffers substantial damage. Flood damage to embankment has a strong correlation with the magnitude of flood. The properties and infrastructure suffer substantial damage during large and medium floods. It is noted that in addition to damages, there are consequential effects such as reduced employment, industrial production loss, reduced consumer demand, reduced economic activities due to disruption to daily life of poor people, etc. When converted into monetary term, it is found that flood damage to infrastructure and property outweighs the damage to crops. But the misery of the people however cannot be translated into economic indices. The 1988 flood caused over 1,517 deaths and damages variously estimated at about $1,200 million. The lower death toll in the 1998 flood of less than 1,000 and a considerable reduction in livestock deaths (down from 350,000 in 1988 to 26,564 in 1998) reflect improvements in flood preparedness over the intervening period. The 1998 flood forced over a million people out of their homes, damaged 16,000 km of roads and 4,500 km of embankment, and destroyed crops of over 500,000 ha of land. 9.2.2 EROSION Morphological behavior of the Bangladesh rivers are very unpredictable and in some cases unstable. This has placed them at constant risk from erosion but is most marked along the major rivers and their estuaries. The Jamuna is highly unstable and has occupied its present course for approximately only the last 200 years. Although over the last 25 years there is a negligible net Westward migration overall, both banks are eroding at a rate of about 70 m/year that shows no sign of abating (Nizamuddin, 2001). The Ganges and Padma Rivers erode their banks locally, while the lower Meghna is extremely active at Chandpur, in the region of the Tetulia channels, and in the entire area of Bhola, Hattiya and Sandwip Islands. The impact of erosion can be sudden and dramatic, even when the riverbank is protected. Border river erosion is also an essential issue for Bangladesh. River training and erosion control can be very expensive in human terms because of the amount of land acquisition required. The amount of land needed varies but often a broad strip of riverside land is required. The Flood Action Plan (FAP) 21/22 investigations of river training on the Jamuna required 42 hectares of riverbank land to be procured, so dislodging and disenfranchising many poor families from along the riverbank chars, often with inadequate compensation for land and livelihood lost. Future compensation for land acquired and livelihoods lost, on the basis of the Bhairab Bridge model would be expected to be much more extensive and thus act as a disincentive to large-scale land acquisition. H. S. M. FARUQUE AND MD. L. ALI 233 Copyright © 2005 Taylor & Francis Group plc, London, UK River training can also cause social conflict, especially if access to the river for navigation and port facilities, fishing, irrigation, and livestock washing is disrupted. Facilities for mooring are still highly limited and are inadequate under some existing riverbank protection schemes. Many people have been displaced and outstanding cases and claims arising from previous water sector projects have yet to be resolved. Policy stresses the adoption of socially sensitive, multi-purpose schemes and adherence to participatory planning as ways of rectifying these fundamental points of conflict. The popular structural options practicing in Bangladesh for erosion control are: • Hard points; • Continuous revetments. 9.2.3 DROUGHTS Drought occurs when rainfall is absent for a prolonged period of time, causing earth to parch, wells to dry, underground water level to fall, crops to wither leading to crop failure and scarcity in fodder for livestock. Because of meager supply of water, food and fodder both humans and livestock suffer untold miseries. In some places women had to wake up at midnight to track 5 km to a well to fetch a pitcher full of drinking water (NWMP, 2001). In other areas the affected people relentlessly dug in dry riverbeds and ultimately ended up with a pitcher full of foul smelling, muddy, brackish water unfit for human consumption. Water supplies, the environment, crops and navigation all fall under threat during droughts. In contrast to the high rainfall brought by the Southwest monsoon from May to October, there are months without rain in the dry season. This can bring hardship to people living in areas with poor access to surface water and ground water resources. There were severe droughts in Bangladesh in 1979, 1981, 1982 and 1989 and between November of 1998 and April of 1999; there was a period of 150 days with almost no rain in Bangladesh. A GoB report of the Task Force on Drought on what was seen as an impending drought in 1995 noted that the rainfall in the monsoon had been below average in the NW, SW, NE, SE and SC Regions (Fig. 9.2) by 35%, 20%, 25%, 30% and 15% respectively. Corresponding reduction in surface water availability was expected to be 20%, 20%, 5%, 10% and 5%. Overall, it was expected that the areas under Low Lift Pump (LLP) irrigation would reduce by 55,000 ha. They also expected that GW level would fall by 0.5 m to 3 m, and that 90,000 Shallow Tube Wells (STW) would be affected. The report stated that aman crop production in the 1994 season was reduced by 377,000 tons due to the effects of the drought. The effect of drought is more marked now that irrigated boro (dry season) rice has become the major rice crop. Streams and water bodies used for LLPs dry up, and STWs reach their suction limit of 7 m. Farmers using LLP start abstracting water reserved for environmental needs. STW can be lowered 2 m in pits to reach more water, but deeper setting is difficult. When farmers draw the water down, there is a corresponding fall in the village hand pumps, which are also suction mode pumps, set generally on higher land and consequently more vulnerable. Women seek water from contaminated surface water sources as a result, with corresponding risks to public health and welfare. Thus water supplies, the environment, crops and navigation are all under threat during droughts. Drought monitoring and contingency plans will be prepared for regions that experience recurrent seasonal shortages of water. These will include action to limit the use of ground water to human needs if necessary. Obviously, human needs must take precedence over non-consumptive needs. The government can empower Local 234 WATER RESOURCES MANAGEMENT IN BANGLADESH Copyright © 2005 Taylor & Francis Group plc, London, UK Government, or any local body it deems fit, to exercise its right to allocate water in scarcity zones during periods of severe drought. This will clearly need to be planned judiciously to avoid bias in allocation to one sector at the expense of another. Fig. 9.2 Map of 8 hydrological regions as in NWMP, 2004. 9.2.4 LOW FLOW SITUATION There are 57 international rivers flowing over Bangladesh with 54 of them entering from India and 3 are from Myanmar. There have been disputes over sharing the water of the international rivers. There is only one Treaty signed in 1996 with India to share waters of the Ganges River in the dry season (January-May). Bangladesh needs these water sharing treaties/agreements on all other international rivers to estimate the magnitude of cross-border inflows in order to facilitate its water management plans. Presently especially in dry season due to upstream withdrawal/control most of the river flows fall dramatically to a very low level on which Bangladesh has no control. H. S. M. FARUQUE AND MD. L. ALI 235 Copyright © 2005 Taylor & Francis Group plc, London, UK 9.2.5 WATER MANAGEMENT During the past decades since 1960s huge investments (an average annual development allocation from the financial year 1990-1991 to 2000-2001 was 173 million dollars) have been made in flood management, drainage and irrigation schemes and to reclaim and develop many polder areas. In these areas a careful water management is required to get optimal results from the investments in the physical infrastructure and enable the farmers to have a reasonable living. However, although in the initial year after completion of the polder projects it gave remarkable results but now over the years the actual water management in the Flood Control and Drainage (FCD/FCDI) schemes of coastal polders has been below expectation, resulting in lower yields than were envisaged during the feasibility, design and construction stages. Water management in FCD schemes is complex and fundamentally different from traditional water management in irrigation systems. A distinct characteristic of water management in FCD schemes is that there are many different stakeholders, each with different, often-conflicting water management demands. The stakeholder’s occupation or the location of the land owns determine his level of interest in water control. So, participation of stakeholders in the context of FCD schemes in Bangladesh is crucial for the planning and design of sustainable water management schemes. 9.2.6 CLIMATE VARIABILITY AND CHANGE The IPCC (2001) in its Third Assessment Report concluded that there was new and stronger evidence that most of the warming observed over the second half of the last century was attributable to emissions resulting from human activities. It further observed that it was very likely that the 20 th century warming has contributed significantly to the observed sea level rise, through thermal expansion of seawater and widespread loss of land ice. Projected temperature, precipitation, extreme weather events and sea level rise have been summarized in Box 9.1. In Bangladesh and the adjacent region, mean observed temperature change in the last century was 0.4°C, which is comparable to the observed global mean temperature change (0.6 ± 0.2°C). No discernible changes in precipitation were observed in the same period. The mean tidal level at Hiron Point (in the Sundarbans) has shown an increasing trend about 4.00 mm/year. Similarly near Meghna Estuary and near Cox’s Bazaar it has registered a positive trend of 6.00 mm/year and 7.8 mm/year respectively. The increment in SLR along the Bangladesh coast is much more pronounced as compared to the global rate (SMRC, 2000). 236 WATER RESOURCES MANAGEMENT IN BANGLADESH Copyright © 2005 Taylor & Francis Group plc, London, UK Bangladesh, one of the most densely populated countries in the world, is a victim of frequent natural calamities like tropical cyclones, storm-surges, tornadoes, floods and droughts. In the wake of global climate change, the SLR has emerged as a new threat. The SLR is likely to have greater impact on Bangladesh due to its low and flat topography and a vast floodplain. Since 21% of the population lives in the low coastal belt, any increase in sea level will be a problem of ominous proportion for Bangladesh (SMRC, 2000). Sea level and temperature rise, increased evaporation, changes in precipitation and resultant changes in cross boundary river flows are identified as the agents of change, which cause the most threatening impacts in the natural, social and economic systems of the country. Climate change in the future may compound water resources management problems in Bangladesh. People in Bangladesh are generally adapted to natural climate variability. However, there is a necessity of a greater focus on adaptation in the context of climate change when serious socio-economic damages are expected to occur. In the water resources sector, the following key areas have been identified for adaptation: drainage congestion, reduced freshwater availability, disturbance of morphologic processes and increased intensity and duration of flooding associated with river erosion and disasters. This chapter addresses possible impacts, key water management issues and adaptation measures for the water resources sector in the context of future climate change. Section 9.3 illustrates present water management practices. Section 9.4 describes major studies carried out on the complex water systems in Bangladesh and states salient findings. 9.3 WATER MANAGEMENT PRACTICES An important characteristic for classifying Flood Control and Drainage (FCD) schemes is the type of flooding they are subjected to. This classification ties in with the four different types of floods in Bangladesh, namely: • Rainfall floods; • River floods; • Tidal or coastal flooding; • Flash floods. It is possible to classify FCD schemes as drainage-only schemes, high level of protection against river flood schemes, protection against tidal flooding (coastal polders) schemes and protection against flash flood (Haors - partial protection by submersible embankment) schemes. Flash floods may occur in the Eastern, Northern and the Northeastern areas of the country at anytime during the wet season. A flash flood is characterized by a sharp rise followed by a comparatively rapid recession. The duration of high flood stages may be for a few days only. A rapid rise in river stage and associated high velocity may cause large damage to crops and properties. The tidal floods, is typical for the coastal zone. Coastal areas consist of large estuarine channels, extensive tidal flats, and low-lying islands. High tides regularly inundate large tract of these areas. During extreme monsoon storms freshwater runoff from the big rivers, combined with wind and wave set-up caused by strong Southern winds, inclines the sea surface on the Bay of Bengal. Therefore the maximum water levels are higher than the predicted tides. Tide levels determine the inland tidal flooding with saline tidal waters, causes damage to standing crops. Wet season floods and water scarcity during the dry season are major challenges for water resources development and water management in Bangladesh. Cropping patterns H. S. M. FARUQUE AND MD. L. ALI 237 Copyright © 2005 Taylor & Francis Group plc, London, UK and crop yields in the floodplains are strongly affected by floods, as are fisheries and transportation. In coastal areas, salinity and cyclones are additional factors influencing farming systems. Over the years the primary objective of water management activities focused heavily to increase agricultural production through the provision of one, or any combination, of the following measures: flood control, drainage, reduction of salt intrusion, and irrigation. The most commonly used structural options for flood control measures practiced in Bangladesh are: a) river embankments, b) construction of dams, c) reforestation, d) network as drainage channels, and e) pump drainage. Flood Control and Drainage (FCD) schemes are located in the floodplains of the rivers in Bangladesh and also in the coastal areas. Embankments along the periphery provide protection against river, or sea floods, or against salt intrusion. Where necessary, sluices are placed in the embankments to drain natural khals (natural channels which connect the low-lying area and the rivers). Many inland FCD schemes have field depressions that contain water during most or all of the year, called beels, in their interior. They are often connected to rivers through a network of khals or man-made canals and can only be drained when river levels permit. In most FCD schemes there are nowadays three distinct cropping seasons, namely: Kharif-I (mid-April to mid-July), Kharif-II (mid-July to mid-November) and Rabi (mid-November to April). From an agricultural perspective the FCD schemes are designed to: • Protect standing aus against early river floods (Kharif-I); • Expand the area under aman by excluding flood from the schemes (Kharif-II); • Retain water in the system during the post-wet season (Rabi). Water management is a dominant feature of life in rural Bangladesh. It has many forms and is regulated by many institutions, including customary rights, traditions and social norms, as well as more formal types of organizations. Every farmer, every fisherman and the villagers who are not a farmer or a fisherman manage water, both individually and collectively. In addition, there are specialized groups whose whole livelihood depends on their ability to manage these resources: professional fishing communities, boatmen, net makers, shrimp farmers, salt producers, irrigation pump owners and many others. Water management in FCD schemes is the control of water surpluses, shortages and quality by adequate operation and maintenance of system elements as canals, sluices, and embankments to obtain optimal conditions for activities within the boundaries of the FCD scheme. 9.3.1 WATER MANAGEMENT CONFLICTS All the stakeholders of a polder do not have the same interest. So, conflicts are found in almost all types of FCD schemes. These conflicts prevail between: • Large farmers and small or marginal farmers; • Highland and lowland farmers; • Farmers and fishermen; • Farmers and boatmen; and • Protected versus unprotected neighborhoods. 238 WATER RESOURCES MANAGEMENT IN BANGLADESH Copyright © 2005 Taylor & Francis Group plc, London, UK For various reasons operation and maintenance of the FCD schemes is not up to the mark. Lot of effort is still needed to improve this situation. 9.3.2 ROLE OF FCD/FCDI SCHEMES The rural economy of Bangladesh is changing under the influence of many other factors than water control interventions. New crops and cropping techniques now emerged, new markets developed, transport patterns changed, population pressure increased, new investments are made, technologies for managing land and water improved and many other developments imply that rural areas are experiencing dynamic transformations. FCD schemes created a physical environment for intensive cultivation with High Yielding Varieties (HYV) crops. They helped in two ways first by saving crops for damages, second created opportunity for irrigation practices. In most cases FCD schemes are justified on the grounds that they will improve conditions for agriculture. More particularly, depending on the scheme, it is argued that (Flood Plan Coordination Organization, 1992): • Reductions in normal wet season water levels, duration, and rates of rise in water level will encourage farmers to adopt more productive crops (rice varieties) which cannot tolerate unmanaged wet season conditions; • Damages due to unusual floods will be reduced, resulting in higher average yields for a given crop; • Reduced variation in wet season conditions will reduce the risks faced by farmers, who are then encouraged to adopt HYV technology (which would otherwise entail high losses in flood years, while the costs of production are higher); • Irrigation makes a change possible from low yielding rabi crops to more profitable and productive HYV boro in the dry season. 9.3.3 IMPACTS ON AGRICULTURE The primary objective of the FCD schemes of increasing food production has largely been achieved. The farmers are ready to invest in more input required by High Yielding Varieties (HYV), partly because there are fewer losses due to flooding (Flood Plan Coordination Organization, 1992). In some of the schemes, the targeted agricultural growth rates were exceeded considerably. In others, the targets seem to have been too high. Most of the gain in production has come from the shift to improved varieties of rice, which shows the confidence of the farmers in the performance of the schemes. Drainage congestion is the major constraint to further growth in rice production. Improvements in design and maintenance would result in further increase, especially if the drainage problem can be dealt with adequately. In a floodplain setting, some drainage congestion is probably unavoidable and a costly solution may not be feasible. The agricultural performances in the four selected FCD schemes are summarized in Table 9.2. 9.3.4 IRRIGATION AND GROUND WATER In Bangladesh irrigation is categorized as either minor or major irrigation. Minor irrigation comprises mostly of farmer-operated and owned tube wells and low-lift pumps, and also a small area irrigated by government owned DTWs and small Local Government Engineering Department (LGED) projects (85%). Major irrigation comprises the Bangladesh H. S. M. FARUQUE AND MD. L. ALI 239 Copyright © 2005 Taylor & Francis Group plc, London, UK 240 WATER RESOURCES MANAGEMENT IN BANGLADESH Copyright © 2005 Taylor & Francis Group plc, London, UK [...]... guidelines in June of 199 5 the Government of Bangladesh expressed its commitment to participatory water management in FCD schemes In April of 199 8 the Bangladesh Water Development Board came out with the revised guidelines In view of too many guidelines already formulated and more than one agency being involved in the process, in May of 199 9, an inter-agency taskforce committee was constituted to integrate... to changes in climate parameters Increase in demand on surface resources Reduced transboundary surface water inflows into Bangladesh Disturbance of existing morphological processes by the changed balance between wet and dry season flows and changes in sediment transport and deposition caused by changes in flows and water levels This will affect riverbank erosion and channel sedimentation Increased incidence... committee to coordinate climate change activities (planning and design) in Bangladesh Strengthen the existing structure and ongoing processes to develop and implement integrated water resources management and strengthen integrated coastal zone management, focusing on protection, land-use and water management Alternative crops, livelihoods attention to water management and access to local coping and adaptation... Series I, Volume 40, Springer Velag, Berlin, Germany, 199 6, pp.11 7-1 34 Huq, S., Ahmed, A U and Koudstaal, R.: Vulnerability of Bangladesh to Climate Change and Sea- Level Rise In T E Downing (ed.), Climate Change and World Food Security, NATO ASI Series I37, Springer Verlag, Berlin, Hiedelberg, 199 6, pp.34 7-3 79 Huq, S., Ali, S I and Rahman, A A.: Sea Level Rise and Bangladesh: A Preliminary Analysis, Journal... sweet water capture fisheries resources are dependent on inland water bodies The annual flooding and post-flood standing water in the floodplains has a significant role in fish production In the wet season, floodplains play the primary role of re-population and increase of biomass in open water fishery production systems However within the flood controlled areas the culture fisheries have expanded... saline/freshwater interface in the ground water aquifers (every cm of sea level rise will result in a thirty-fold rise of the interface because of the hydrostatic pressure balance); Percolation from the increased saline surface waters into the ground water systems; Increasing evaporation rate in winter, leading to enhanced capillary action and subsequent salinization of coastal soils; and Increasing... rainfall and unchanged evapo-transpiration in the monsoon results in increased GW recharge By contrast, the combination of unchanged rainfall and increased evapo-transpiration in the dry season results in increased demands Because of its very low elevation and exposure to various water related hazards, Bangladesh is at great risk from global climate change Although the magnitude of the changes in climate. .. Bangladesh in 198 7 and 198 8 attracted worldwide attention and resulted in a concentrated international effort to find a long-term solution to the persisting flooding problem As a result the Flood Action Plan (FAP) was initiated in 198 9, which was coordinated by the World Bank The Government of Bangladesh setup the Flood Plan Coordination Organization (FPCO) in 199 0 to supervise, coordinate and monitor... Special Issue, 199 5 Intergovernmental Panel on Climate Change (IPCC) :Climate Change 2001: The Scientific Basis, Cambridge University Press, U.K., 2001 Ministry of Water Resources (MWR): National Water Policy, MWR, Bangladesh, Dhaka, 199 9 Mirza, M M Q.: Three Recent Extreme Floods in Bangladesh: A Hydro-Meteorological Analysis In: Flood Problem and Management in South Asia (M M Q Mirza, A Dixit and A Nishat... financial measures and incentives, including delineation of water rights and water pricing; To bring institutional changes that will help decentralize the management of water resources and enhance the role of women in water management; To develop a legal and regulatory environment that will help the process of decentralization, sound environmental management, and improve the investment climate for the . This can bring hardship to people living in areas with poor access to surface water and ground water resources. There were severe droughts in Bangladesh in 197 9, 198 1, 198 2 and 198 9 and between. a good water policy in Bangladesh. The National Water Policy was finalized in 199 9 (Ministry of Water Resources, 199 9). In this policy it was noted, among others, that the lack of inter-agency coordination. public and private water delivery systems with appropriate legal and financial measures and incentives, including delineation of water rights and water pricing; • To bring institutional changes