groundwater droughts in bangladesh

Water Resour Manage (2010) 24:1989–2006DOI 10.1007/s11269-009-9534-y

Groundwater Drought in the Northwestern Districtsof Bangladesh

Shamsuddin Shahid · Manzul Kumar Hazarika

Received: 28 February 2007 / Accepted: 13 November 2009 /Published online: 27 November 2009© Springer Science+Business Media B.V. 2009

Abstract Prolonged absence of groundwater within the operating range of shallowtube-wells during dry season is a common problem in the northwestern districts ofBangladesh in the recent years. In this paper, groundwater scarcity and drought inthree northwestern districts of Bangladesh have been investigated. The CumulativeDeficit approach from a threshold groundwater level has been used for the compu-tation of severity of groundwater droughts. Monthly groundwater fluctuation datacollected from 85 sites is used for the study. The study shows that groundwaterscarcity in 42% area is an every year phenomenon in the region. Analysis of ground-water hydrographs and rainfall time-series reveals that ever increasing groundwaterextraction for irrigation in the dry season and recurrent droughts are the causes ofgroundwater level drop in the region.

Keywords Groundwater droughts · Cumulative deficit · Standardized precipitationindex · Groundwater hydrographs · GIS · Bangladesh

1 Introduction

Groundwater is the main source of irrigation in the northwestern districts ofBangladesh. About 75% water for irrigation in the region comes from groundwater

S. Shahid (B)Department of Geology, University of Malaya, 50603 Kuala Lumpur, Malaysiae-mail: [email protected]

M. K. HazarikaGeoinformatics Center, Asian Institute of Technology, Km 42-Paholyothin Highway,Klong Luang, Pathumthani 12120, Thailande-mail: [email protected]

1990 S. Shahid, M.K. Hazarika

(Bari and Anwar 2000). According to a recent BADC survey (Bangladesh Agri-cultural Development Corporation 2002), the ratio of surface water and ground-water use for total irrigated agriculture has been changed drastically in last twodecades in Bangladesh. The contribution of groundwater has increased from 41%in 1982/1983 to 75% in 2001/2002 and surface water has declined accordingly. Theratio of groundwater to surface water use is much higher in northwestern districts ofBangladesh compared to other parts of the country. Cross-country anthropogenicactivities caused a severe negative impact on water resources and eco-systems ofnorthwestern Bangladesh in the recent years. All the rivers and cannels of thearea dry up during the dry season and make the people completely dependent ongroundwater. The area is also highly prone to droughts because of high rainfallvariability (Shahid 2008; Shahid and Behrawan 2008). Groundwater becomes theonly source of water during dry period in the region. The national water policy ofBangladesh government also encouraged groundwater development for irrigationboth in the public and the private sectors. Government poverty alleviation programthrough the introduction of special groundwater-based irrigation project in the areanamed as Barind Multi-purpose Development Project (BMDP) has accelerated theuse of groundwater. After the introduction of BMDP in 1986, 6,000 deep tube-wellsare installed in the area. In addition to that about 66,000 shallow tube-wells are alsoinstalled in private sectors by the year of 2000 for the exploitation of groundwater forirrigation. Number of shallow and deep tube-wells used for irrigation in Bangladeshduring the time period of 1983–2000 is shown Fig. 1. The figure shows a rapid increaseof shallow tube-wells meaning higher use of groundwater from shallow aquifers inthe country after 1995.

BMPD took necessary initiatives to ensure annual withdrawal less than theannual recharge to keep the groundwater level in position. They have estimatedgroundwater recharge in the area at least one-third of the annual rainfall and that isabout 500 mm/year (Asaduzzaman and Rushton 2006). Islam and Kanumgoe (2005)estimated the long-term annual average recharge of 152.7 mm using water balancestudy and aquifer simulation modeling. A government report suggests that rechargeto groundwater in the northwestern part varies from 210 to 445 mm. However,

Fig. 1 Number of shallow and deep tube-wells used for irrigation in Bangladesh during the timeperiod of 1983–2000 (After: Bangladesh Agricultural Development Corporation 2005)

Groundwater Drought in the Northwestern Districts of Bangladesh 1991

exploitation of groundwater in the area is going on the basis of one-third rainfallrecharge hypothesis of BMDP which is beyond the sustainable yield according toIslam and Kanumgoe (2005).

The overexploitation has caused the ground water level falls to the extent of notgetting fully replenished in the recharge season. The groundwater-based irrigationsystem in the area has reached a critical phase as the phreatic water level has droppedbelow shallow wells in many places. The recently published groundwater zoning mapshows that a record high of 60% irrigated croplands in Naogaon and 10% in Rajshahiand C’Nawabganj districts have become critical for shallow tube-well operation(Bangladesh Agricultural Development Corporation 2005). Prolonged absence ofgroundwater within the range of shallow tube-wells, particularly during dry season,is a major problem in the area. The problem is becoming progressively more acutewith the growth of population and extension of agriculture. Though a number ofresearch works have been carried out on hydrogeology (Ahmed and Burgess 1995;Begum et al. 1997; Islam and Kanumgoe 2005), groundwater occurrence potential(Haque et al. 2000; Azad and Bashar 2000) and groundwater dynamics (Shwetset al. 1995; Jahan and Ahmed 1997; Rahman and Shahid 2004) of the study area,no study has been carried out so far to investigate the cause of groundwater leveldeclination and droughts. In the present paper, spatial distribution of groundwaterdroughts, trends in groundwater hydrographs and relation of groundwater level withmeteorological droughts have been analyzed to study the severity of groundwaterscarcity and its probable causes in Northwest Bangladesh. It is expected that thestudy will help local water resource management and agricultural organizations aswell as the development/planning authorities to improve their understanding forsustainable groundwater resource management in the region.

Hydrological drought is defined as the deficiencies in surface and subsurface watersupplies, which lead to a lack of water availability to meet normal and specificwater demands (Demuth and Bakenhus 1994). Groundwater drought is a particulartype of hydrological drought that occurs when groundwater recharge, heads ordischarge deviate from normal (van Lanen 2005; Tallaksen and van Lanen 2004).Calow et al. (1999) defined groundwater drought as a situation where groundwatersources fail as a direct consequence of drought. According to van Lanen and Peters(2000), a groundwater drought occurs if in an aquifer the groundwater heads fallbelow a critical level over a certain period of time, which results in adverse effects.Groundwater droughts are often out of phase with both meteorological and agricul-tural droughts (Wilhite and Glantz 1985; Tallaksen and van Lanen 2004). Withinthe hydrological drought sequence groundwater is the last to react to a droughtsituation (Mendicino and Versace 2007). Therefore, a groundwater drought is usuallylags behind the deficient precipitation. Groundwater levels which provide indirectknowledge about groundwater recharge and discharge are used in the present paperto study groundwater drought. The cumulative deficit (CD) approach from thresholdgroundwater levels proposed by van Lanen and Peters (2000) is used to measure theseverity of droughts.

2 Description of the Study Area

The study area comprises three northwestern districts of Bangladesh viz. Rajshahi,Naogaon and C’Nawabganj. The location of the study area in Bangladesh is shown in


Fig. 2a. The location of water-well used for the collection of time series of groundwa-ter data and study groundwater droughts is shown in Fig. 2b. Geographically, the areaextends from 24◦08′ N to 25◦13′ N latitude and from 88◦01′ E to 89◦10′ E longitude,and covers approximately 7,587 km2. The topographic map of the study area is shownin Fig. 3a. The topography of the area is mainly flat with an average elevation of25 m above the mean sea level. There is a mild surface gradient towards southeast.The geological map of the study area is shown in Fig. 3b. The surface geology in amajor part of the area comprises of uplifted terraces of Pleistocene sediments calledBarind Tracts which are more strongly weathered than the surrounding alluvium. Inthe areas with alluvial, the Barind Tract sediments can be found at depths of the orderof 150–200 m or more. A number of hydrogeological studies have been carried out inthe area (Jahan et al. 1994; Ahmed and Burgess 1995; Shwets et al. 1995; Jahan andAhmed 1997; Begum et al. 1997; Haque et al. 2000; Azad and Bashar 2000; Rahmanand Shahid 2004; Islam and Kanumgoe 2005; Faisal et al. 2005; Asaduzzaman andRushton 2006). The studies show that upper aquifers in the region are unconfinedor semi-confined in nature. The thickness of the exploitable aquifer ranges from 10to 40 m. Jahan et al. (1994) computed the specific yield of the aquifer in the areavary from 8% to 32% with a general decreasing trend from north towards centralportion. The maximum depth to groundwater table from land surface varies from7 to 30 m. Most of the shallow tube-wells which are widely used for irrigation inthe area go below the suction lift capacity in the peak irrigation period (BangladeshAgricultural Development Corporation 2005). A moderate deficit of rainfall in a yearcauses groundwater level to decline in the area.

Three distinct seasons can be recognized in the area from climatic point of view:(1) the dry winter season from December to February, (2) the pre-monsoon hotsummer season from March to May, and (3) the rainy monsoon season which lastsfrom June to October (Rashid 1991). Climatically, the study area belongs to dryhumid zone with annual average rainfall vary between 1,400 and 1,650 mm, amongwhich almost 83% rainfall occur in monsoon (June to October). Rainfall in the areavaries widely from year to year. For example, the rainfall recorded at Rajshahi in1997 was 2,062 mm, but in 1992 it was 798 mm only. Average temperature in theregion ranges from 25◦C to 35◦C in the hottest season and 9◦C to 15◦C in the coolestseason. In summer, some of the hottest days experience a temperature of about 42◦Cor even more. In winter it falls to about 5◦C. So the region experiences extremes thatare clearly in contrast to the climatic condition of the rest of the country (Banglapedia2003).

Dryness study of Bangladesh, carried out using De Martonne aridity index (DeMartonne 1926) and Thornthwaite precipitation effectiveness index (Thornthwaite1931) methods, revealed that the study area belongs to sub-humid class (Shahid et al.2005). De Martonne and Thornthwaite indices are 20.89 and 64.04 respectively inthe study area which is lowest in the country. The total annual potential evapotran-spiration is also lower than or equal to annual rainfall in some places. Therefore, theclimate of this region of Bangladesh is sometimes defined as very close to dry (Shahidet al. 2005).

Monthly rainfall recorded in the meteorological station situated in RajshahiDistrict, which is the only meteorological station in the study area, for the timeperiod of 1964–2002 is shown in Fig. 4. Trend of annual rainfall is calculated bylinear regression method to assess the historical change in rainfall in the area. As


Fig. 2 a Location of studyarea in Bangladesh; b locationof groundwater samplingpoints used to study spatialextents of groundwaterdroughts


Fig. 3 a Topographic; and b surface geology maps of the study area

the time series of rainfall are not very long, Kendall-tau (Conover 1980) trendestimation is also used to compare the result obtained from linear regression. Thesignificance of the time trends has also been assessed by using Mann–Kendall test(Kendall 1975). The linear regression and Kendall-tau trend give values of −0.49and −0.11 respectively which are not statistically significant. This means that there isno significant change in long-term annual rainfall in the study area.

Meteorological drought is a common phenomenon in the region (Shahid andBehrawan 2008). In last 40 years the area suffered eight droughts of major mag-nitude. Though all the droughts had severe impact on quality of life and economyof the whole country, the northwestern districts were affected more compared toother parts of the country (Shahid 2008). In recent decades, the hydro-climaticenvironment of northwestern districts of Bangladesh has been aggravated by the

Fig. 4 Annual average rainfall time series for the period 1964–2002 recorded in a meteorologicalstation located at Rajshahi


cross country anthropogenic interventions. Construction of barrage in the upstreamof Ganges River and diversion of water by India has reduced the water dischargeof the Ganges River in Bangladesh from 3,700 m3/s in 1962 to 364 m3/s in 2006.The shortage of freshwater discharge to the deltaic area is trailing active ecosystemsfunction, especially in the dry season. Falling groundwater tables, increase watersalinity and losses of bio-diversity has been observed in the Gangetic basin ofBangladesh in the recent years (Islam and Gnauck 2008).

The economy of the area is completely agriculture based. About 75% land of thestudy area is used for agriculture among which 31% land is used for single cropping,56% for double cropping and 13% land is used for triple cropping. Cultivation in 59%land in the area is under irrigation and almost 75% of the irrigation water comes fromgroundwater. Unlike other region of the country, most part of the study area is freefrom flood. Groundwater in the area is mainly recharged by rainwater. Groundwaterin the Barind Tract is relatively free from Arsenic (Acharyya et al. 2000).

3 Data and Methods

Five years (1998–2002) monthly groundwater level data collected from 85 sites in thestudy area is used to study the spatial distribution of groundwater droughts. Locationof data collection points are shown in Fig. 2b. Long term monthly groundwaterfluctuation data, starting from mid-1980s to 2002, available in nine sites in the studyarea, is used to analyze the groundwater hydrographs and correlate groundwaterlevel with meteorological droughts. Thirty-nine years (1964–2002) monthly rainfalldata recorded in the meteorological station located at Rajshahi is used to identifymeteorological drought events and severity. Methods used to study groundwaterdroughts in the area are discussed below.

Groundwater droughts can be identified using three variables viz. recharge,groundwater levels and discharge from groundwater to the surface water system(Tate and Gustard 2000; van Lanen and Peters 2000). Recharge and groundwaterdischarge cannot be measured directly. They are calculated from other measure-ments or through simulation. This makes them sensitive to errors. One the otherhand, groundwater levels characterize the present storage and they can be measureddirectly with reasonable accuracy and frequency. Indirectly the spatial and temporalaspects of groundwater levels provide knowledge about groundwater recharge anddischarge. Therefore, in most of the cases, groundwater levels are monitored todetect groundwater droughts.

The most well known methods used in groundwater drought analysis from ground-water level data are the threshold level approach and the Sequent Peak Algorithm(Tallaksen and van Lanen 2004). However, as groundwater level is a state variableand not a flux like recharge, rainfall and stream flow, the deficit volume calculatedwith the threshold level approach can identify groundwater droughts or scarcitiesbetter compared to other approaches. Although the fixed threshold provides quiteacceptable results, the cumulative deficit is preferred as the major droughts can beidentified more clearly. The best results can be obtained for a fixed threshold leveland the cumulative deficit (van Lanen and Peters 2000; Peters and van Lanen 2000).Therefore, in the present study, the cumulative deficit (CD) approach from thresholdgroundwater levels is used to identify groundwater droughts.


The cumulative deficit is the summation of groundwater level departed below athreshold level over a time period. Following van Lanen and Peters (2000), in thepresent study groundwater drought events in a year is identified by calculating thecumulative deficit in meter below a threshold groundwater level:

CDi = CDt−1 +{

(φD − φt) i f positive0 otherwise

(1)

where:

φt represents groundwater level in meter in a particular month of the year, andφD means the threshold level in meter.

Because of slow reactions of groundwater level on rainfall, only major meteoro-logical droughts are finally shown up as a groundwater drought. Therefore, the timestep to be used in the analysis of a groundwater drought should necessarily be large,usually more than a week or a month (Peters and van Lanen 2000). Therefore, in thepresent study monthly time step is used for the study of groundwater droughts. Threethreshold levels viz. 30%, 20% and 5% of the mean groundwater level is computedto show the severity of groundwater scarcity or drought at each location.

Cumulative deficit (CDt) values at different locations are interpolated to show thespatial extent of groundwater droughts of different severity. Kriging method (Isaaksand Srivastava 1989) is used for the interpolation of CDt values. Geostatisticalanalysis tool of ArcMap 9.1 is used for this purpose.

Standardized precipitation index (SPI) (McKee et al. 1993) method has been usedto identify meteorological drought and wet events from rainfall time series data. SPIhas also been used to correlate drought and wet events with groundwater level. SPIcan be calculated simply by taking the difference of the precipitation (xi) from themean (xi) for a particular time step, and then dividing it by the standard deviation(σ ). However, computation of SPI becomes complicated when the SPI is normalizedto reflect the variable behavior of precipitation for time steps shorter than 12 months.To overcome this problem, historic rainfall data are usually fitted to a gammadistribution. This is done through a process of maximum likelihood estimation ofthe gamma distribution parameters, α and β. This allows the rainfall distribution atthe station to be effectively represented by a mathematical cumulative probabilityfunction (McKee et al. 1993). Based on the historic rainfall data, the probabilityof the rainfall being less than or equal to a certain amount is then identified. Ifa particular rainfall event gives a low probability on the cumulative probabilityfunction, it indicates a likely drought event. On the other hand, if a particular rainfallevent gives a high probability on the cumulative probability function, it indicates alikely wet event. Detail theory of SPI can be found in McKee et al. (1993).

4 Spatial Extents of Groundwater Droughts

Spatial extent of groundwater droughts for three threshold levels viz. 30%, 20%and 5% of mean groundwater level for the years from 1998 to 2002 are shownin Figs. 5, 6 and 7 respectively. The mean groundwater level is calculated from5 years (1998–2002) monthly groundwater level fluctuation data. The figures showthat groundwater scarcity is a regular phenomenon in the northwestern districts of


Fig. 5 Spatial extent of groundwater droughts in the study area computed for a threshold of 30% ofthe mean groundwater level for the years 1998–2002




Bangladesh especially in the eastern side of Rajshahi district and northwestern side ofNaogaon district. Due to the scarcity of long-term data in all the points, no statisticalanalysis was possible to correlate the spatial extent or severity of groundwaterdroughts with the amount and distribution of rainfall. Spatial extents of groundwaterdroughts with different severity are analyzed in this section only to get an overviewof groundwater drought situation in the study area. Figure 5 shows that groundwaterin at least 42% area goes below 30% of the mean level in every year. Cumulativedeficit more than 2 m is also evident almost every year in some sites. Figure 6 revealsthat in 39% area groundwater level goes below 20% of the mean level in every year.Though the groundwater drought-affected area varies from year to year, Fig. 7 showsthat groundwater level drop below 5% of the mean level is also common in someparts of Rajshahi district in every year.

The long-term groundwater level data available in few sites of the study area areanalyzed and correlated with meteorological droughts in the following sections of thepaper to get an idea about possible causes of groundwater droughts in the area.

5 Analysis of Groundwater Hydrographs

Long-term groundwater level fluctuation data available in nine sites in the study areashow two types of nature viz. (a) Type-1: gradual decrease of minimum groundwaterlevels, but no apparent change in maximum level, and (b) Type-2: gradual decreaseof both minimum and maximum groundwater levels. Two sample long-term ground-water fluctuation data of Type-1 and Type-2 are shown in Fig. 8a and b respectively.Both the figures show that average level of groundwater has been declined during


Fig. 8 Two sample groundwater hydrographs in the study area a Type-1; and b Type-2

the time period 1986–2002. However, the most serious effect is the longer periodof groundwater absence above a certain level. The Fig. 9a and b show groundwatertable below certain levels in different months during the time period 1986–2002 forthe sample hydrographs of Type-1 and Type-2. Figure 9a shows that groundwaternever declined below 20 m before 1991, but it is common phenomena in the monthsof April and May after 1995. Long absence of groundwater table below 10 and 15 mis also noticeable after 1995. Similar situation can be found in Fig. 9b. Declination


Fig. 9 Availability of groundwater above certain levels for the sample hydrographs of a Type-1; andb Type-2 in different months during the time period 1986–2002

of groundwater level below 7 m was found to occur only during the months of Apriland May in the early years, but in the recent years it is common even for the wholeyear.

6 Relation of Groundwater Level and Rainfall

The relation of rainfall and groundwater regimes for the area is shown in Fig. 10. Fiveyears monthly rainfall and monthly average groundwater fluctuation data available


Fig. 10 Relation of rainfall amount and groundwater table height above the mean sea level in thestudy area

at different points around the rain-gauge station are used to draw the relation. Thefigure shows a 2-month lag between maximum groundwater table and the peak in therainfall amount. The 2-month lag of groundwater level with rainfall amount meansthat a deficit in monsoon rainfall or an early departure of monsoon in 1 year maycause groundwater drought in following pre-monsoon period. Groundwater droughtdue to rainfall deficit of 1 year may also continue almost 2 months after the beginningof monsoon in the next year.

7 Meteorological Droughts and Groundwater Level

The standardized precipitation index (SPI) time series for 6-month and 1-year timesteps for the time period 1964–2002 are shown in Fig. 11a and b respectively. Thefigure shows severe droughts (SPI > −1.5) in the years of 1968, 1969, 1973, 1982,1989, 1992 and 1994–1995 for both 6-months and 1-year time steps in the study area.The SPI provides a comparison of the precipitation over a specific period with theprecipitation totals from the same period for all the years included in the historicalrecord. For example, a 6-month SPI of October compares the May to Octoberprecipitation total in that particular year with the May to October precipitation totalsof all the years. Consequently, it facilitates the temporal analysis of rainfall deficit orexcess. SPI of October computed for 6-month time step and SPI of April computedfor 1-year time step for the years 1985–2002 in the study area are given in Table 1.6-month SPI in October represents rainfall deficit or excess in monsoon (May toOctober) and 1-year SPI in April represents rainfall deficit or excess in the wholewater year.

Within the hydrological drought sequence groundwater is the last to react to adrought situation, consequently groundwater droughts are often out of phase withmeteorological droughts. Comparison of SPI values with minimum groundwaterlevel for the time period 1986–2002 in the study area is shown in Fig. 12. The 6-monthSPI values of October and 1-year SPI values for April are used for comparison.About 88% of rainfall occurs during the months of May to October in the area.Generally, if there is a rainfall deficit during this period (May–October) in 1 year and


Fig. 11 Standardized precipitation index for a 6-month; and b 1-year time steps

no excess rainfall in the pre-monsoon months of the next year, groundwater levelgoes below the average minimum groundwater level in the beginning of monsoon.On the other hand, if there is an excess of rainfall in the monsoon of 1 year, theminimum groundwater level is higher than the average minimum groundwater levelin the beginning of monsoon in the next year. It can be noticed from Fig. 12 that upto the year 1995 groundwater level follows the general relation with rainfall deficitas it is the main source of groundwater replenishment in the region. But the trendis different after 1995. Though there were few wet year after 1996 onwards, theminimum groundwater levels have not increased proportionately. This is due to theover-exploitation of groundwater in the region by shallow tube-wells.

However, meteorological drought is also responsible for groundwater level dropin the region. A deficit of monsoon rainfall in 1988 caused the aquifers in the areanot to recharge completely. Consequently, the groundwater level drops to minimumlevel in the month of May–June of 1989. An excess and well distributed rainfall inthe year of 1990–1991 helps the groundwater level to recover to normal. Deficit ofmonsoon rainfall in 1994 caused a declination of groundwater to minimum level inthe beginning of monsoon of 1995. Successive deficit of monsoon rainfall during


Table 1 Six-month SPI ofOctober and 1-year SPI ofApril during the time period1985–2002

Year 6-month SPI in October 1-year SPI in April

1985 −0.69 0.471986 0.01 −0.541987 0.89 0.011988 −1.02 0.811989 −0.17 −1.221990 0.71 0.031991 0.03 0.471992 −2.21 0.081993 0.30 −1.851994 −1.16 0.321995 −0.09 −1.131996 −0.62 −0.021997 1.58 −0.551998 0.18 1.501999 1.51 −0.082000 0.35 1.542001 −0.03 0.022002 −0.16 −0.01

the years of 1995–1996 has caused a further declination of groundwater in theconsecutive years. After 1996 groundwater level continued to decline with a littleresponse to excess rainfall in monsoon or non-monsoon months. This is due to theover exploitation of groundwater for irrigation in the region. A sharp declination ofgroundwater is observed in 2001 due to a huge deficit of pre-monsoon rainfall in thatyear. Rainfall during the months of November to April in 2000–2001 was only 22 mmcompared to 225 mm in 1999–2000.

From the SPI time series and minimum groundwater level curve it can be observedthat both the 6-month SPI at the end of monsoon and 1-year SPI at the beginning ofmonsoon can indicate natural fluctuation of groundwater level in the study area. Toassess the capability of SPI to predict the minimum groundwater level correlation

Fig. 12 Comparison of 6-month SPI of October and 1-year SPI of April with minimum groundwaterlevel for the time-period 1986–2002


coefficients between SPIs and minimum groundwater level are calculated. As thenumber of data points is less and the data are not normally distributed non-parametric correlation coefficients are calculated by using Spearman rank correla-tion. A correlation coefficient of 0.23 is found between 6-month SPI of October andminimum groundwater level of next year. On the other hand a correlation coefficientof 0.14 is found between 1-year SPI of April and minimum groundwater level of thatyear. However, none of the correlations are significant at the 95% level of confidence.Therefore, it can be said that only qualitative change in groundwater level can beguessed from SPI values, quantitative prediction of groundwater level is not possiblefrom SPI. Rainfall deficit is not the single cause of groundwater level drop in thestudy area, but also due to over exploitation of groundwater resources. Therefore, itis not possible to predict the minimum groundwater level using SPI only.

8 Discussion and Conclusions

It is usual has that groundwater level responses to precipitation at certain time lag.Therefore, groundwater drought in this region has a direct relation with meteorolog-ical drought. If there is no severe anthropogenic intervention in groundwater system,the cause of groundwater droughts is mainly the deficiency in precipitation. The studyshows that up to the year of 1995 groundwater level follows the general relationwith rainfall deficit or excess as it is the main source of groundwater replenishmentin the region. Severe drought in 1994–1995 and overexploitation of groundwaterfor irrigation after 1995 have caused the ground water level recedes deeper in theconsecutive years. Insufficient field information to quantify the recharge and non-consideration of groundwater level based pumping management has caused over-exploitation of groundwater. Though, it has been found that in some cases theaquifers replenish fully during monsoon, large-scale abstraction of groundwater haslowered the groundwater table in dry season which has made the exploitation ofgroundwater costly for irrigation in the area.

Water scarcity is caused by an imbalance between water supply and demand.Groundwater drought in the study area is caused both by the reduction of supplyand increase of demand. Demands of groundwater have been increased due to theextension of agricultural lands and cropping intensities. Huge withdrawal of waterin the international rivers in dry season and recurrent occurrence of droughts havereduced the supply of surface water as well as made the people more dependent ongroundwater for irrigation. Therefore, it can be concluded that recurrent droughts,rapid expansion of groundwater based irrigation projects and cross-boundary an-thropogenic interventions are the main causes of groundwater droughts in thenorthwestern districts of Bangladesh. As groundwater declination is not only dueto deficit of rainfall, but also due to overexploitation of groundwater resources, itcan be concluded that groundwater droughts in the area is mainly human-induceddroughts which is better to term as groundwater scarcity.

Development of surface water resources for irrigation is essential to reducegrowing pressure on ground water table. In addition, water conservation programis required which would contribute to the recharging of groundwater to maintainbetter hydrologic cycle. Steps are required to regulate the extraction of water in thearea for sustaining rechargeable groundwater aquifers with full public knowledge.


Accurate estimation of groundwater recharge is essential for this purpose. Futureresearch is necessary to estimate the percentage of precipitation that contributesgroundwater recharge in the area for various precipitation events for the indirectestimation of groundwater recharge from precipitation easily. Quantitative informa-tion about groundwater recharge and groundwater management based on sustainingrechargeable groundwater aquifers may prevent groundwater scarcity in the region.

Acknowledgements This work was supported by a Fellowship to Dr. S. Shahid from the Alexandervon Humboldt Foundation, Germany.

References

Acharyya SK, Lahiri S, Raymahashay BC, Bhowmik A (2000) Arsenic toxicity of groundwater inparts of Bengal basin in India and Bangladesh: the role of quaternary stratigraphy and holocenesea-level fluctuation. Environ Geol 39(10):1127–1137

Ahmed K, Burgess W (1995) Bils and the Barind aquifer, Bangladesh. In: Brown AG (ed) Geomor-phology and groundwater. Wiley, New York

Asaduzzaman M, Rushton KR (2006) Improved yield from aquifers of limited saturated thicknessusing inverted wells. J Hydrol 326:311–324

Azad MAS, Bashar K (2000) Groundwater zonation of Nawabganj Sadar Thana and its relation togroundwater chemistry. Bangladesh J Geol 19:57–71

Bangladesh Agricultural Development Corporation (2002) Survey report on irrigation equipmentand irrigated area in Boro/2001 season. Bangladesh Agricultural Development Corporation,Dhaka

Bangladesh Agricultural Development Corporation (2005) The minor irrigation survey report of2005. Dhaka, Bangladesh

Banglapedia (2003) National encyclopaedia of Bangladesh. Asiatic Society of Bangladesh, DhakaBari MF, Anwar AHMF (2000) Effects on irrigated agriculture on groundwater quality in

Northwestern Bangladesh. In: Proceedings of integrated water resources management for sus-tainable development, vol I. New Delhi, pp 19–21

Begum SF, Bashar K, Hossain MS (1997) An evaluation of hydraulic parameters of the aquifer andwells of the western part of the Barind area, Bangladesh. Bangladesh Geosci J 3:49–64

Calow RC, Robins NS, MacDonald AM, Nicol AL, Orpen WRG (1999) Planning for groundwa-ter drought in Africa. In: Proceedings of the international conference on integrated droughtmanagement—lessons for Sub-Saharan Africa, Pretoria, South Africa. pp 20–22

Conover WJ (1980) Practical non-parametric statistics. Wiley, New YorkDe Martonne E (1926) Aérisme et indice d’aridité. C R Acad Sci 182:1395–1398Demuth S, Bakenhus A (1994) Hydrological drought—a literature review. Internal Report of the

Institute of Hydrology, University of Freiburg, GermanyFaisal IM, Parveen S, Kabir MR (2005) Sustainable development through groundwater management:

a case study on the Barind tract. Water Resour Dev 21:425–435Haque MN, Keramat M, Rahman AMA (2000) Delineation of groundwater potential zones in the

western Barind Tract of Bangladesh. J Bangladesh Natl Geogr Assoc 21–26:13–20Isaaks HE, Srivastava RM (1989) An introduction to applied geostatisitics. Oxford University Press,

New YorkIslam SN, Gnauck A (2008) Mangrove wetland ecosystems in Ganges-Brahmaputra delta in

Bangladesh. Front Earth Sci China 2(4):439–448Islam MM, Kanumgoe P (2005) Natural recharge to sustainable yield from the Barind aquifer: a

tool in preparing effective management plan of groundwater resources. Water Sci Technol 52:251–258

Jahan CS, Ahmed M (1997) Flow of groundwater in the Barind area, Bangladesh: implication ofstructural framework. J Geol Soc India 50:743–752

Jahan CS, Mazumder QH, Ghose SK, Asaduzzaman M (1994) Specific yield evaluation: Barind area,Bangladesh. J Geol Soc India 44:283–290

Kendall MG (1975) Rank correlation methods. Griffin, London


McKee TB, Doesken NJ, Kleist J (1993) The relationship of drought frequency and duration totime scales. In: Eighth conference on applied climatology. American Meteorological Society,Anaheim CA, 17–23 January 1993

Mendicino G, Versace P (2007) Integrated drought watch system: a case studyin Southern Italy.Water Resour Manag 21:1409–1428

Peters E, van Lanen HAJ (2000) Hydrological drought—groundwater. In: Hisdal H, TallaksenLM (ed) Drought event definition. Technical Report No. 6: Assessment of the Regional Im-pact of Droughts in Europe, University of Oslo, Norway. Available at http://www.hydrology.uni-freiburg.de/forsch/aride/navigation/publications/pdfs/aride-techrep6.pdf of subordinate doc-ument. Accessed 23 January 2008

Rahman MM, Shahid S (2004) Modeling groundwater flow for the delineation of wellhead protectionarea around a water-well at Nachole of Bangladesh. J Spat Hydrol 4(1):1–10

Rashid HE (1991) Geography of Bangladesh. University Press, DhakaShahid S (2008) Spatial and temporal characteristics of droughts in the western part of Bangladesh.

Hydrol Process 22:2235–2247. doi:10.1002/hyp.6820Shahid S, Behrawan H (2008) Drought risk assessment in the western part of Bangladesh. Nat

Hazards 46:391–413. doi:10.1007/s11069-007-9191-5Shahid S, Chen X, Hazarika MK (2005) Assessment aridity of Bangladesh using geographic infor-

mation system. GIS Dev 9:40–43Shwets VM, Danilov VV, Jahan CS (1995) Seasonal effect on regional groundwater flow: Barind

area, Bangladesh. In: Groundwater management, proceedings of international symposium heldin San Antonio. Texas, pp 14–16

Tallaksen ML, van Lanen HAJ (2004) Hydrological drought—processes and estimation methods forstreamflow and groundwater. Elsevier Sciences, The Netherlands

Tate EL, Gustard A (2000) Drought definition: a hydrological perspective. In: Vogt JV, Somma F(ed) Drought and drought mitigation in Europe. Kluwer Academic, Dordrecht

Thornthwaite CW (1931) The climate of North America according to a new classification. Geogr Rev21:633–55

van Lanen HAJ (2005) On the definition of groundwater drought. In: Abstract of European geo-sciences union general assembly, Vienna, 24–29 April 2005

van Lanen HAJ, Peters E (2000) Definition, effects and assessment of groundwater droughts.In: Vogt JV, Somma F (ed) Drought and drought mitigation in Europe. Kluwer Academic,Dordrecht

Wilhite DA, Glantz MH (1985) Understanding the drought phenomenon: the role of definitions.Water Int 10:111–120

http://www.hydrology.uni-freiburg.de/forsch/aride/navigation/publications/pdfs/aride-techrep6.pdf

http://www.hydrology.uni-freiburg.de/forsch/aride/navigation/publications/pdfs/aride-techrep6.pdf

http://dx.doi.org/10.1002/hyp.6820

http://dx.doi.org/10.1007/s11069-007-9191-5

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