Bangladesh

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Geography, climate and population

Geography

Bangladesh is a low-lying riverine country located in southern Asia, covering a total area of 144 000 km² (Table 1). The country has been formed as the greatest deltaic plain at the confluence of the Ganges, the Brahmaputra (Jamuna) and the Meghna Rivers and their tributaries. It has a common border in the west, north and east with India, a short border with Myanmar in the southeast, and is bounded by the Bay of Bengal in the south.

Administratively the country is divided into 6 divisions, each named after their respective divisional headquarters: Dhaka, Rajshahi, Chittagong, Khulna, Barisal and Sylhet. The Divisions are subdivided into 64 Districts (Zilas) and each District is further subdivided into Upazilas or Thanas, of which there are 508 at present. Finally, each Thana is again subdivided into Unions or Wards, of which there are 6 766 in the country.

About 80 percent of the landmass is made up of fertile alluvial lowland that becomes a part of the Greater Bengal Plain (Lower Gangetic Plain). The country is flat with some hills in the northeast and southeast. A great plain lies almost at sea level along the southern part of the country and rises gradually towards the north. The land elevation in the plain varies from 0 to 90 m above sea level. The maximum elevation is 1 230 m above sea level at Keocradang in the Rangamati hill district. The geo-morphology of the country consists of a large portion of floodplains (almost 80 percent), and some terraces and hilly areas. About 7 percent of the total area of Bangladesh is covered with rivers and inland water bodies and these areas routinely flooded during the monsoon. Forest coverage is about 16 percent of the total area of the country.

Total cultivable area is estimated at 8.77 million ha. In 2008, the total cultivated area was estimated at 8.7 million ha of which 7.9 million ha for annual crops and 0.8 million ha of permanent crops. Most farms own less than 1 ha and a large portion has even less than 0.2 ha.

Climate

Bangladesh has a tropical monsoon climate with significant variations in rainfall and temperature throughout the country. There are four main seasons: the pre-monsoon (March-May), which has the highest temperatures and experiences the maximum intensity of cyclonic storms, especially in May; the monsoon (June-September), when the bulk of rainfall occurs; the post-monsoon (October-November) which, like the pre-monsoon season, is marked by tropical cyclones on the coast; and the cool and sunny dry season (December-February).

About 80 percent of the total rainfall occurs in the monsoon, and the average annual precipitation over the country is 2 320 mm. It varies from 1 110 mm in the extreme north-west to 5 690 mm in the northeast. The country is regularly subjected to drought, floods and cyclones. The country’s mean annual lake evaporation is approximately 1 040 mm which is about 45 percent of the mean annual rainfall.

Mean annual temperature is about 25°C, with extremes as low as 4°C and as high as 43°C. Ground frost can occur in the hills. Humidity ranges between 60 percent in the dry season and 98 percent during the monsoon.

Population

In 2008, the total population is 160 million, of which around 73 percent is rural (Table 1). Bangladesh is one of the most densely populated countries in the world with 1 111 inhabitants/km². The country has succeeded in significantly reducing the population growth rate over the years. While in 1991 the population growth rate was 2.17 percent, presently has come down to 1.39 percent (BBS, 2008). Despite the steadily declining fertility rate, the country’s population is expected to exceed 176 million by 2025 when the population density will rise to about 1 200 persons/km².

In 2008, access to improved drinking water sources reached 80 percent (85 and 78 percent for the urban and rural population respectively).

Economy, agriculture and food security

In 2009, GDP was US$89 360 million of which agriculture accounted for 19 percent (Table 1).

In 2008, the total population economically active in agriculture is estimated at 35.56 million inhabitants, amounting to 47 percent of the economically active population, of which 50 percent is female.

Despite continuous domestic and international efforts to improve economic and demographic prospects, Bangladesh remains still a developing nation. The country was able to achieve only a growth rate of 5 percent since 1990 due to many obstacles, including frequent natural disasters (such as cyclones, floods, droughts) and also poor and inefficient management of economic policies by the government and private sector organizations. Presently, the Government has laid more emphasis on agriculture and rural development, power and energy, small and medium enterprises (SMEs), human resource development, creation of employment opportunities, and increasing investment for pro-poor development activities, with a view to achieve the macro-economic stability by enhancing the annual GDP growth rate.

Agriculture plays a dominant role in the growth and stability of the economy of Bangladesh. The country has a favourable natural environment for crop production. Of the arable land area, 33.3 percent is single cropping, 45 percent double cropping, 11.5 percent triple cropping and 10.2 percent is cultivable waste and currently fallow land. Agriculture is also the prime source of raw materials for most of the industries.

The agriculture sector comprises crops, livestock, fisheries, homesteads and forestry. Within the crop sub-sector food grain, particularly rice, dominates the country’s agricultural scenario with respect to both cropped area and production. Yield of non-cereal crops such as pulses, oil seeds and vegetables including potatoes almost stagnated, while that of wheat has not increase markedly.

Bangladesh made steady progress in crop agriculture during the post liberation periods. Growth in the agricultural sector averaged over 3 percent per year during the 1970s and the early 1980s. Thereafter, the average growth rate declined to about 1.7 percent due to slowdown in irrigation development, the unprecedented flood damage of 1987 and 1988 and the Government cutback in development expenditures for agriculture. Despite the sluggish growth rate of the agriculture sector, food grain production increased at an annual rate of 3 percent during the early 1990s. Much of the increase in production came from irrigated Boro rice. The cropping intensity increased from 148 percent to 180 percent and food grain production almost doubled during the period from 1970 to 1993. During 2000-01, total rice production in the country was 25.08 million tons. Since then, food grain production, particularly rice crop production, has increased steadily though it has to depend on the vagaries of nature. Total rice production during 2007-08 was 31.67 million tons (DAE, 2009) and wheat production in the same year was 0.74 million tons (BBS, 2008). Such achievements have been possible due to Government efforts through the introduction of high yielding varieties (HYV), small-scale irrigation, modern inputs like fertilizers and pesticides and use of agricultural mechanization.

Despite the growth in food production and its availability, food insecurity is still a major problem mainly because of the lack of purchasing power and thus of access to food, especially for the ultra poor. A major portion of the rural population is landless, and as labourers they depend on casual earning for their livelihood. Due to the seasonal variation in agricultural employment and limited employment opportunities in the non-farm sector, millions of people suffer from chronic and transitory food insecurity. So, national level food grain availability does not mean household food security. In spite of the increased food grain production and the reduction of the real price of rice, over half of the country’s population cannot afford an adequate diet. The Government has identified food security as an important factor contributing to its socio-economic stabilization and development (MoF&DM, 2006).

Water resources and use

Water resources

Most of Bangladesh is located within the floodplains of three great rivers: the Ganges, Brahmaputra and Meghna (GBM), and their tributaries, such as the Teesta, Dharla, Dudhkumar, Surma and Kushiyara. The three major river systems drain to the Bay of Bengal through Bangladesh:

• The Brahmaputra River enters Bangladesh from the north and flows south for 270 km to join the Ganges River at Aricha, about 70 km west of Dhaka in central Bangladesh;
• The Ganges River flows east-southeast for 212 km from the Indian border to its confluence with the Brahmaputra, then as the Padma River for about a further 100 km to its confluence with the Meghna River at Chandpur;
• The Meghna River flows southwest, draining eastern Bangladesh and the hills of Assam, Tripura and Meghalay of India to join the Padma River at Chandpur. The Meghna then flows south for 160 km and discharges into the Bay of Bengal.

The combined discharge of the three main rivers is among the highest in the world. Peak discharges are of the order of 100 000 m³/s in the Brahmaputra, 75 000 m³/s in the Ganges, 20 000 m³/s in the upper Meghna and 160 000 m³/s in the lower Meghna.

There are 230 rivers crisscrossing the country, most of which are either tributaries or distributaries to the GBM river systems. Total length of the river courses is approximately 24 000 km and the total catchment area of the GBM is about 1.75 million km², out of which only 7 percent lies within Bangladesh. There are 57 transboundary rivers in the country, of which 54 are shared with India and the remaining 3 originate in Myanmar.

On average almost 1 106 km³ of water crosses the borders of Bangladesh annually, of which 85 percent between June and October. Around 54 percent (599 km³) is contributed by the Brahmaputra, 31 percent (344 km³) by the Ganges and nearly 15 percent (163 km³) by the tributaries of the Meghna and other minor rivers.

Because of the great disparity between the monsoon floods and the low flow during the dry season, the manageable surface water resources are considered being 80 percent of the dependable flow in March. Surface water resources are used extensively for dry season irrigation, mainly Boro rice using low-lift pumps (LLPs) and traditional devices.

The availability of groundwater resources in Bangladesh is determined by the properties of the groundwater storage reservoir and the volume of annual recharge. Key factors which determine groundwater availability include the capacity of the country’s aquifers to store water, and the characteristics which govern economic withdrawal of groundwater for irrigation, domestic and industrial needs. The source of recharge is rainfall, flooding, and stream flow in rivers. The quaternary alluvium of Bangladesh constitutes a huge aquifer with reasonably good transmission and storage properties. Heavy rainfall and inundation during the monsoon help the aquifers to be substantially recharged annually.

A regional groundwater recharge assessment took place in 1987 by Master Plan Organization (MPO) under the National Water Plan (NWP) of the Ministry of Water Resources. Subsequently, MPO updated the groundwater resources assessment during the NWP Phase–II in 1991 and the average annual available groundwater recharge for the country was estimated 21 km³ (Table 2).

The internal renewable water resources are estimated at 105 km³/year (Table 3). The overlap being considered negligible, this includes 84 km³ of surface water produced internally as stream flows from rainfall and about 21 km³ of groundwater resources produced within the country. Part of the groundwater comes from the infiltration of surface water with an external origin. Since annual cross-border river flows and entering groundwater are estimated to be 1 105.64 km³, the total renewable water resources are therefore estimated at 1 210.64 km³.

In 2007 there was only one multipurpose dam, located at Kaptai in Rangamati Hill district. The total capacity of this dam is 20.3 km³. In addition, there are three barrages constructed across the Teesta, Tangon and Manu rivers which are used as diversion structures for irrigation purposes only.

In 1995, the installed capacity of all the country’s power plants was about 2 907 MW, of which about 230 MW was hydroelectric.

Water use

In 2008, the total water withdrawal was estimated at about 35.87 km³, of which about 31.50 km³ (88 percent) for agriculture, 3.60 km³ (10 percent) for municipalities and 0.77 km³ (2 percent) for industries (Figure 1).

Approximately 28.48 km³, or 79 percent of the total water withdrawal, comes from groundwater and 7.39 km³, or 21 percent, from surface water (Figure 2).

International water issues

India controls the flow of the Ganges River through a dam completed in 1974 at Farraka, 18 km from the border with Bangladesh. This dam was a source of tension between the two countries, with Bangladesh asserting that the dam held back too much water during the dry season and released too much water during monsoon rains. A treaty was signed in December 1996 under which Bangladesh is ensured a fair share of the flow reaching the dam during the dry season. Such agreements for other transboundary rivers are yet to be made for equitable share of surface water resources of the country.

Irrigation and drainage development

Evolution of irrigation development

Irrigation is considered being a necessary precondition to enhance agricultural production of Bangladesh. The earliest approach to irrigation facilities was through constructing large-scale multipurpose irrigation, flood control and drainage projects during 1960-70. These projects were successful to some extent for flood control and protecting coastal areas from tidal bores and saltwater intrusion. But they played a minor role in irrigation development of the country and only about 7 percent of the total irrigable area of the country was covered by those very costly projects. Though the country has abundant surface water resources, particularly in the monsoon season, its flat deltaic topography and the instability of major rivers make large gravity irrigation systems both technically difficult and costly. On the other hand, during the dry season irrigation using surface water has become difficult or practically impossible due to limited availability of surface water. Therefore the use of groundwater for irrigation has become increasingly important.

The expansion of minor (small-scale) irrigation is a vital component of the Government’s agriculture strategy. Minor irrigation consists of low lift pumps (LLP: power operated centrifugal pumps drawing water from rivers, creeks and ponds), shallow tubewells (STW: with a motorized suction mode pumping unit), deep tubewells (DTW: with a power operated force mode pumping unit), manually operated pumps (MOP: extracting water from a shallow tubewell) and traditional systems. At the end of the dry season, the water level falls beyond the suction limit of the centrifugal pump. In these situations, it is possible to draw water by placing the STW in a pit. A STW in a pit is called a deep-set shallow tube-well (DSSTW) or a very deep-set shallow tubewell (VDSSTW). Where static water levels fall further (over 10.7 m), a submersible or vertical turbine (FMTW: force mode tubewell) is needed.

Between 1950 and 1987, public tubewells, regulations governing private installations and public monopolies in the supply of pumps, motors and other equipment were a constraint on the development of irrigation. Since 1972, the emphasis has been on minor irrigation through low lift pumps and tubewells (STW, DTW and FMTW).

From 1979 to 1984, there was a liberalized expansion of minor irrigation, mainly with STW in the private sector. In 1982, about 1.5 million ha were under food crop irrigation. The rate of minor irrigation development slowed from 39 000 STW in 1984 to less than 5 000 in 1986. This was due to a number of reasons: private sector STW sales were limited, there was official concern over reported declines in groundwater levels where STW operated, an embargo on all diesel engines was imposed in 1985, and engines were standardized.

In 1991, the National Minor Irrigation Development Project (NMIDP) was established in response to the needs of farmers and the requirement for increased private sector investment in minor irrigation technologies. The project activity mainly concentrated on VDSSTW and FMTW technology, whereas irrigation by STW was mainly controlled by the private sector. In 1994, 665 VDSSTW and 32 FMTW had been constructed by farmers as a result of the promotional action of the project. However, there has been a general reduction in the area irrigated by wells as a consequence of aquifer drawdown, and there has been an increase in salinity intrusion particularly along the coastal areas in the southwest of the country.

Currently, the irrigation potential is estimated at 6.93 million ha. During 2006, there were 29 170 DTW, 1 202 720 STW and 107 290 LLP and the total irrigated area was estimated at 4.88 million ha; where groundwater and surface water coverage were 81 percent and 19 percent, respectively. In 2008 the national irrigation coverage was 5.05 million ha, where groundwater covered 79 percent and surface water covered 21 percent of the total irrigated area (Table 4 and Figure 3). A summary of irrigation through utilization of surface water and groundwater by different modes during 2008 is presented in Table 5.

In 1993, the total area of wetlands was 3.14 million ha, of which almost 1.55 million ha were cultivated. Thus, total water managed area is estimated at 6.59 million ha.

Surface irrigation is the only technology used in large irrigation schemes. In 2008, the total area equipped for full control irrigation covered by large irrigation schemes (major irrigation) was estimated at 0.14 million ha (3 percent). Small irrigation schemes covered a total area of 4.91 million ha (97 percent) (Figure 4).

In 1992, the average cost of irrigation development for large surface water schemes operated by Bangladesh Water Development Board (BWDB) was estimated at US$522/ha as reported by FAO (2007). At that time the operation and maintenance (O&M) costs of these projects was estimated at about US$100/ha; but under the 1983 Irrigation Ordinance, BWDB collected only Tk250/ha (nearly US$6/ha) as O&M fees. The average cost of irrigation development in minor irrigation schemes including O&M was estimated at about US$50/ha in 1990-91; but in the recent years this cost raised to US$113/ha (BBS, 2008).

Role of irrigation in agricultural production, the economy and society

In 2008, total harvested irrigated cropped area was estimated at 5.98 million ha, of which the most important crops are rice accounting for 4.34 million ha (73 percent), wheat 0.31 million ha (5 percent), potatoes 0.26 million ha (4 percent) and vegetables 0.24 million ha (4 percent) (Table 4 and Figure 5).

Improved irrigation water management (IWM) practices, increased use of modern variety (MV) seeds and fertilizers have made a major break through in achieving almost the self sufficiency of cereal crop production of the country. Irrigation is mainly practiced in the dry season for cultivating Boro rice and wheat. Supplementary irrigation could appreciably increase transplanted Aman rice production by mitigating the drought effects.

Irrigated paddy yield is moderately high, ranging from 3.85 to 4.75 tons/ha. During 2007-08 total Boro rice production (including HYV, hybrid and local varieties) amounted to 18.67 million tons and the total rice (Aus, Aman and Boro together) was 31.67 million tons (DAE, 2009). The total irrigated rice production was about 58 percent of the total rice production of the country.

Status and evolution of drainage systems

Because of the low-lying topography, about 26 500 km² or 18 percent of the country is inundated during monsoon season each year. During severe floods the affected area may exceed 53 000 km² or 37 percent of the country and in extreme events like 1998 flood about 66 percent of the country is inundated. Floods are caused by overspills from main rivers and their distributaries, overspills from tributaries and by direct rainfall. Flood control works can reduce floods from the first two, but only drainage can have any effect on the latter two. The basic benefit of drainage is water control – supply as well as removal. The particular benefits can be: i) potential increase in cropped area through earlier drainage; ii) higher yields from transplanted Aman rice through early planting; iii) crop diversification in the wet season through better drainage; and iv) more control over crop calendars and patterns through control of the water regime.

In 1964, a master plan for water resources development was developed. This envisaged the development of 58 flood protection and drainage projects covering about 5.8 million ha of land. Three types of polders were envisaged: gravity drainage, tidal sluice drainage and pump drainage.

Flood control and drainage projects have accounted for about half of the funds spent on water development projects since 1960. They include:

• Large-scale projects such as the Coastal Embankment Project (949 000 ha), the Manu River Project (22 500 ha), the Teesta Right Embankment (39 000 ha), the Ganges-Kobadak Project (141 600 ha), the Brahmaputra Right Flood Embankment (226 000 ha), the Chandpur Irrigation Project (54 000 ha), and the Chalan Beel Project (125 000 ha);
• Medium-scale projects such as the Sada-Bagda, Chenchuri Beel and Bamal-Salimpur-Kulabasukhali projects implemented under the Drainage and Flood Control Projects (DFC I to DFC IV) and financed by the World Bank. These projects typically cover areas of 10 000 30 000 ha and involve flood control and drainage with limited irrigation development;
• Small-scale projects such as those implemented under the Early Implemented Project, the Small-scale Irrigation Project and the Small-scale Drainage and Flood Control Project.

During the National Water Plan Phase I and Phase II period (1986-1991) the Master Plan Organization (MPO) made comprehensive assessment of the ongoing water resources development projects (large-scale irrigation projects, flood control and drainage (FCD) projects, and flood control, drainage and irrigation (FCDI) projects. It was envisaged that the performance of FCD and FCDI projects need to be improved under the NWP. The main emphasis of the FCD projects under this NWP strategy would be on gravity drainage schemes in shallow to medium flooded areas, and submersible embankments in deeply flooded areas. After 1991, FCD projects were implemented under the Flood Action Plan (FAP) by the MoWR. This was a comprehensive plan for the progressive reduction in floods from major rivers in association with improved drainage systems. Under the existing Five Year Plan (Planning Commission, 2009), the Government has approved 12 FC and FCD investment projects in the current Annual Development Programme (ADP) (2009-2010).

In 1993, the total area of wetlands was 3.14 million ha, of which 1.55 million ha were cultivated and 1.38million ha were drained through surface drains. In 1992, the average cost of drainage development was US$192/ha.

Different types of floods occur in Bangladesh. Of the total cropped area, about 1.32 million ha are severely flood-prone and 5.05 million ha are moderately flood-prone. The flood protected area in 1990 was estimated at 4.20 million ha.

Water management, policies and legislation related to water use in agriculture

Institutions

In Bangladesh, public sector involvement in irrigation water management (IWM) is shared among three Ministries. Minor irrigation and small-scale surface irrigation schemes lie under the jurisdiction of the Ministry of Agriculture (MoA) and the Ministry of Local Government, Rural Development and Cooperatives (LG&RD), respectively. Large-scale irrigation schemes, including FCD projects, are under the Ministry of Water Resources (MoWR).

The MoA is mainly concerned with agricultural policy development, planning and monitoring. Project delivery is the responsibility of its various agencies, the most important being the Bangladesh Agricultural Development Corporation (BADC). In the past, the BADC was directly involved in supplying inputs to minor irrigation and looked after the O&M of all sorts of equipments. But, it has withdrawn from all commercial operations relating to minor irrigation, leaving them to the private sector. The Department of Agriculture Extension (DAE) demonstrates and extends information to farmers on crops, agronomic practices and use of on-farm water management and agricultural machineries. The Barind Multipurpose Development Authority (BMDA) under MoA is also responsible for water resources management in agricultural development of the Barind Tracts region. The Local Government Engineering Department (LGED) under the MoLG&RD implemented Small Scale Water Resources Development (SSWRD) projects Phase I and II by constructing 26 Rubber Dams in the medium and small rivers of different parts of the country. LGED also was responsible for participatory management of these projects by formulating the Water Management Cooperative Associations (WMCAs) for each project. Recently the Bangladesh Rural Development Academy (RDA) under the MoLG&RD is implementing package model of Multipurpose Low-Cost DTW Projects in different parts of the country with a view to achieving optimum utilization of water resources for irrigation, domestic and other purposes like fisheries, livestock raring and nurseries. These multiple uses bring significant benefits and contributions to the livelihoods, especially for poor households.

Under MoWR the Bangladesh Water Development Board (BWDB) is responsible for the planning, implementation and operation of medium- and large-scale surface water irrigation schemes, FC and FCD projects. The Water Resources Planning Organization (WARPO) under the same ministry has a mandate to ensure coordination of all relevant ministries through the National Water Council and to plan all aspects of water resources development including large-scale and minor irrigation, navigation, fisheries and domestic water supplies.

Water management

Water Management (WM) is considered as the planned development, distribution and use of water resources, in accordance with predetermined objectives with respect to both quantity and quality of water. WM deals with integration of all activities aimed at a systematic control of the inter-relationship between water and society with the main purpose of decreasing damages caused by water on the one hand and exploiting it on the other hand in a technically and economically viable way. Therefore, WM has become the important issue nowadays to combat the increasing pressure on the available water resources. Agriculture is the greatest consumer of water resources, accounting for approximately 88 percent of all the freshwater withdrawn (Figure 1). Modern high-yield and diversified crop production systems can be sustained only with proper utilization of irrigation water and management at the farm level.

Though there has been a significant increase in irrigated agriculture in the country over the last decade, most of the minor and major irrigation systems have shown poor field performances due to lack of technical know-how as well as poor on-farm water management (OFWM) practices. The Government has recognized the importance of introducing at farm-level appropriate techniques and technologies in water management as a key area for ensuring food security, employment generation and elimination of poverty through intensification and diversification of agricultural production. With this view, MoA has undertaken some development projects for improving the efficiency and overall performance of irrigation systems through better OFWM practices. Few investment projects were initiated by the Government and some were financed by donor agencies under Technical Assistance (TA) programme.

Participation of women in IWM activities has not been encouraged, though their activities in other agricultural practices such as post-harvest processing, home gardening, rearing of livestock and poultry are found in many villages. However, treadle pumps are operated for irrigation by women here and there. Moreover, the indigenous and tribal women are involved in collecting water for domestic purposes and irrigating homestead gardens.

Policies and legislation

In Bangladesh, no policy or act related to irrigation or water management has been formulated yet. Due to the rapid growth of minor irrigation through the use of DTW and STW during 1980s, MoA enacted the Groundwater Management Ordinance in 1985 controlling the spacing for installation of irrigation equipments. But this Ordinance was suspended in 1987 with a view to expansion of minor irrigation (mainly STW irrigation) to the private sector. Due to suspension of space requirements of irrigation equipments, optimum utilization of groundwater resources has been impeded. However, in recent years Government policies such as the National Agriculture Policy – NAP (MoA, 1999), National Water Policy – NWPo (MoWR, 1999) and the National Water Management Plan – NWMP (MoWR, 2001) addressed the minor irrigation and water management issues to some extent.

Minor irrigation has been largely in the domain of the private sector agriculture, which caused significant increase in crop production and there has been rapid expansion of irrigated agriculture. In this perspective the Government has given special emphasis on minor irrigation development in the NAP formulated in 1999. In relation to irrigation water management the mandate of the NWPo (MoWR, 1999) is to focus on increasing efficiency through drainage water recycling, rotational irrigation, water conserving cropping patterns and conjunctive use of both surface water and groundwater, non-point pollution of water systems by fertilizer and pesticides, and equity and social justice. The NWMP, which has been formulated by MoWR in 2001, is mandated to address the overall water resources management issues of Bangladesh and provides directions for the short-, medium- and long-term action plans. In the NWMP emphasis has been put on the expansion of private STW irrigation in the slow-growth regions, and issues related to arsenic pollution and salinity especially in the coastal areas are to be addressed.

Environment and health

Bangladesh is now widely recognized to be one of the countries most vulnerable to climate change. Increased variability of temperatures and rainfall and increased occurrence of natural hazards are expected to affect the availability of both surface water and groundwater. Investments are needed to ensure a continuous and sustainable access to water resources.

Due to the limited availability of surface water during dry season the use of groundwater has become increasingly important source of water for irrigation, municipal and industrial purposes. Some environmental hazards have been encountered in many areas and a number of adverse effects have emerged due to overexploitation of groundwater, such as lowering of water tables, reduction in dry season flows of rivers and streams, groundwater pollution, intrusion of saline water in coastal areas, ecological imbalance and the possible land subsidence. There has been evidence of permanent depletion of groundwater levels in some locations, particularly in Dhaka Metropolitan area where the average annual decline of water level is about 3 m (BADC, 2006) and in the NW region of the country.

The area salinized by irrigation was estimated at 100 000 ha in 1993.

Irrigation water quality has deteriorated in some locations due to pollution of from agrochemicals, industrial waste and other sources. Arsenic contamination of groundwater, particularly water from STW and HTW within 59 out of 64 districts of the country, has been reported in many government and donor agency documents (GoB, UNICEF, WB, FAO). The arsenic concentration has been found maximum within the upper 50 m depth of aquifers in most regions of the country (Water Aid, 2000). In many places concentration of iron and arsenic in irrigation water has gone beyond the limit of safe water quality standards of Bangladesh and WHO. Some diseases and health hazards like arsenicosis, blindness, physical disability, occur due to arsenic toxicity to human body (RDA, 2001). Throughout the country, about 1.44 million tubewells (STWS and HTWs have been affected by arsenic contamination and about 30 million people are exposed to arsenic toxicity (Ahmed, 2007).

In some parts of the country, particularly the Barind Tracts within the NW region, there are already symptoms of deterioration in the natural hydrological regime, water quality effects on soils and growth of agricultural crops, health hazards and effects on the flora and fauna due to decline of groundwater levels. Therefore, careful consideration should be given to these environmental issues in order to harness the beneficial uses of irrigation water comprising both surface water and groundwater resources.

Prospects for agricultural water management

Under a climate change situation with increased temperature, evapotranspiration will increase and the river system will suffer during dry months due to acute low-flow condition. Consequently, the dry season water demand for irrigated agriculture, salinity control, and stream flow maintenance will increase significantly leading to increased shortfall of water supplies. Towards meeting these increasing gaps in water availability, cooperation among the riparian countries for augmenting dry season flows in the transboundary rivers need to be given more emphasis.

The main source of irrigation water during the last decade has been groundwater. There is a question of risky overdependence of utilizing groundwater due to quality constraints and some emergent environmental consequences. The NWMP (MoWR, 2001), therefore, focuses on some short-term and long-term strategies in agricultural water management aspects, such as: i) balanced conjunctive use of surface water and groundwater resources; ii) future growth of tubewell irrigation through Force Mode Tubewells (FMTWs); iii) surface water conservation and rainwater harvesting using Rubber dams in small and medium rivers; iv) new low-cost major irrigation schemes (gravity flow system); and v) larger floating pumps, particularly in the south-eastern part of the country.

On-farm water management (OFWM) can be considered as a potentially useful measure to save irrigation water use per hectare and to expand the irrigation command area, mainly for STW and LLP irrigation within the coastal zone and other water crisis areas of the country. Wherever feasible, tubewell (TW) irrigation should be integrated with domestic water supply. The RDA developed multipurpose low-cost DTW technology package can be replicated in suitable areas also.

According to the estimates of the NWP in 1991, the expansion of irrigation coverage would reach its maximum potential limit by the year 2025. However, the rate of increase in water demand is expected to register a declining trend in response to demand management practices like conservation, water use efficiency, recycling.

The strategy of water resources development has so far been centred on flood control and irrigation expansion to promote food grain production. Not denying the importance of food production and food security, it is now widely recognized that conflicts among alternative and competing uses of water are becoming sharper as the demand for water has been increasing. It is, therefore, necessary to formulate a long-term vision for Integrated Water Resources Management (IWRM) to address the demands of all water using sectors in order to maintain a sustainable environment.

Some challenging issues in relation to agricultural water management, like arsenic pollution, climate change, salinity, have been encountered nowadays in many locations. The impacts of arsenic hazard and climate change have already been discussed. The salinity front in the coastal areas of Bangladesh has already been advanced due to reduced freshwater flows, caused by upstream abstraction of the Ganges water. About 10 percent of the SW region experiences increased salinity in the wet season, which rises to around 40 percent in the dry season (BWP, 2000). The salinity problem adversely affects the availability of required irrigation water in this region. The possible solution to this particular problem can be taking advantage of the Ganges Water Sharing Treaty of 1996 between India and Bangladesh where specified quantities of water release downstream of Farraka has been assured for the dry season. A major endeavour to that end is the Gorai Restoration Project, now under implementation. Moreover, assured in-stream flows in the Ganges have facilitated the potential for surface water augmentation in the SW region through the construction of the proposed Ganges Barrage.

Main sources of information

Ahmed, M. Feroze. 2007. Integrated water resources management in Bangladesh. RSS Workshop on IWRM, Bangladesh University of Engineering & Technology, Dhaka.

BADC [Bangladesh Agricultural Development Corporation]. 2006. Groundwater zoning map and its application. A National Seminar Paper presented by Eftekharul Alam, April 9, Sech Bhaban, Dhaka.

BWP [Bangladesh Water Partnership]. 2000. Bangladesh Water Vision 2025 – Towards a sustainable water world. Global Water Partnership/BWP, Dhaka.

BBS [Bangladesh Bureau of Statistics]. 2008. Statistical Pocket Book of Bangladesh. Ministry of Planning, GoB.

DAE [Department of Agricultural Extension]. 2009. Agriculture Diary 2009. Agricultural Information Service Wing, DAE, Ministry of Agriculture, GoB.

FAO. 2007. Water Profile of Bangladesh. Updated Version (June, 2007).

MPO [Master Plan Organization]. 1986. National Water Plan Summary Report. Ministry of Water Resources, GoB/UNDP.

MPO. 1987. The groundwater resource and its availability for development. Technical Report 5, National Water Plan Phase –I, Ministry of Water Resources, GoB.

MPO. 1991. National Water Plan Phase II. Vol I & II, Ministry of Water Resources, GoB.

MoA [Ministry of Agriculture]. 1999. National Agriculture Policy (NAP). GoB.

MoA. 2008. Minor irrigation survey report 2007-08. Survey and Monitoring Project, BADC, October, Dhaka.

MoF&DM [Ministry of Food and Disaster Management]. 2006. National workshop on food security. Dhaka

MoWR [Ministry of Water Resources]. 1999. National Water Policy (NWPo). GoB.

MoWR. 2001. National Water Management Plan. GoB.

Planning Commission. 1998. The Fifth Five Year Plan, Ministry of Planning. GoB.

Planning Commission. 2009. The Annual Development Programme (ADP) 2008-09. Ministry of Planning, GoB.

RDA [Rural Development Academy]. 2001. Safe drinking water supply through RDA- developed low-cost deep tubewell. A Report prepared by M.A. Matin, M.H. Khan and M.N.I. Khan, RDA, Bogra, November 2001.

Water Aid. 2000. An overview of the arsenic issues in Bangladesh. Edited by M. Jones Elizabeth, Water Aid Bangladesh, Dhaka.

WARPO [Water Resources Planning Organization]. 2009. National water resources database (NWRD). Ministry of Water Resources, GoB.

UN [United Nations]. 2009. World population prospects (Table-A.1 2008 revision). Department of Economic and Social Affairs, Population Division.