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The present study on chemistry, environmetrics and quality index of 116 groundwater samples collected in pre- and post-monsoon periods in the years of 2014 and 2015 from the drought-prone Rajshahi City Corporation area, Bangladesh, is carried out for its drinking suitability from management perspective. According to the Bangladesh Drinking Water Standards (2005), parameters like pH, Ca2+, Mg2+, Cl−, Fe(total) and Mn2+ exceed the desirable limit, but within permissible limit without adverse effect except Mg2+ concentration, which accounts for 45% in pre-monsoon period and makes groundwater unsafe for drinking purposes. The groundwater belongs to alkaline earth elements (Ca2++Mg2+) and exceed alkali elements (Na++K+), and weak acids (HCO3−) exceed the strong acids (SO42−) where Ca2+ and HCO3− are dominant ions, and attribute to temporary hardness of groundwater. The groundwater of the aquifer is of Ca2+–Mg2+–HCO3− type. The source of different ions is associated with partial ion exchanges, weathering of calcareous nodules and clay minerals, flow of groundwater system through aquifer lithology, municipal sewerage, anthropogenic influence, etc. The drinking water quality index also reveals that groundwater mostly falls in ‘good’ category having suitability for drinking purposes round the year. But increasing population and water demand in the area may create threat of quality hazard in near future, and regular groundwater quality monitoring should be carried out periodically for supplying safe drinking water to city dwellers.

Present study aims to evaluate the potentiality for the application of rainwater harvesting (RWH) technique through dug well recharge (DWR) system in agro-based drought-prone Barind Tract, NW Bangladesh—the granary. Meteorologically, the climatic condition in the area leads to vulnerability of drought where annual average rainfall amount is about 1300 mm (national average of 2550 mm), but, due to the agricultural practices, huge amount of groundwater is withdrawn for irrigation. The aquifer for large-scale groundwater development exists at greater depth at present. Annual average temperature is 25.93 °C with high average humidity value of 75%. Geophysical survey shows that the top most clay layer of thickness (17 m) of low infiltration capacity is a great barrier for natural groundwater recharge and below top most clay layer sandy aquifer layer of 31 m thickness is considered as potential zone for groundwater development. Groundwater-level (GWL) depletion during the period of 1980–2017 is nearly 9.96 m with an average declining rate of 0.378 m/year. The declining rate of GWL has abruptly increased after 2004. The aquifer is not fully recharged even during rainy season, and the GWL does not reach its original position after 2004. Therefore, groundwater resource is under stress and the situation is worsening due to increasing irrigation demand with extension of command areas. Moreover, temporal variability of precipitation along with the declining trend of GWT is the burning governing factor for RWH system as adaptation strategy. In the present study, an RWH system is operated in the Kakonhat Pourashova of Godagari Upazila through construction of DWR structure where rainwater is harvested from the roofs of Pourashova and auditorium buildings with a catchment area of 692 m2. Here, the amount of water consume by each household is 224 liters per day. The groundwater recharge with RWH technique is operated by the Managed Aquifer Recharge (MAR) technology through dug well (1 m diameter with a depth of 23 m), and includes a recharge box (22 m3) structure filled with sands of different texture act as filter. Considering the run-off coefficient of 0.85 and the annual rainfall of 1300 mm, this DWR structure can harvest 765 m3 of rainwater that can be stored in the aquifer for further use. Otherwise, if this amount of rainwater is not harvested in this way, this would be lost as evaporation due to high temperature and low infiltration capacity of soil, or flowing as run-off water into streams and ultimately to rivers. The research findings presented in this paper could be applied in areas with similar socio-economic status and climatic condition as a novel technique for adaptation measure in drought-prone areas in Bangladesh.

Present study is carried out in the drought prone Barind tract in the north-western part of Bangladesh to identify zones of groundwater potentiality using remote sensing (RS) and geographic information system (GIS) based geospatial multi-criteria approach. Decreasing rainfall trend along with increasing demand for groundwater irrigation of this agro-based area utters urgent need for sustainable groundwater resource development. The study area possesses sub-dendritic drainage pattern with highly irregular to irregular geomorphological character with mostly flat to gentle slope represents 'not so good category' for groundwater development because of lower rainfall with less favorable infiltration capacity of top soil with respect to time of percolation of runoff. Here major portion of runoff water loses and not allows more infiltration to recharge the groundwater and, therefore is less potential for groundwater occurrence and development. To delineate groundwater potentiality, thematic layers like geomorphology, drainage density, rainfall, lithology , lineament density, slope and land use/land cover (LULC) have taken into consideration to integrate in the GIS environment, and has categorized as: 4% (48 km 2) - very good, 13% (170 km2) - good; 25% (342 km2) - moderate; 30% (405 km2) - poor; and 28% (365 km2) as very poor category. On the other hand, this potential zonation is most sensitive to lithology; followed by slope and lineament density; and succeeded by geomorphology, drainage density, rainfall, and LULC. This study helps not only to classify zones of groundwater resource potentiality, but also to assess groundwater resource potentiality and scopes for its future development at a glance and provides a guideline for the groundwater resource management approach particularly in the area.

Drought—recurring natural disaster phenomenon in Barind Tract, Bangladesh—were livelihood faces hardship for water demand. Seasonal rainfall and frequent drought with increasing frequencies since 2005 have thrown challenges for water resource management plan. The Tract with poor–very poor groundwater potentiality has irregular landscape, and most of the rainwater is lost as runoff into nearby canals (Khari), rivers, etc. So, highly groundwater-dependent irrigation system is increasing steadily with time resulting overexploitation and threatening toward resource unsustainability that will be aggravated in coming days. So for sustainable water resource management with high rainwater harvesting potentiality during rainy season, the managed aquifer recharge model—piloted and widely enacted as the integrated water resource management strategy—has operated since 2014 injecting rain/runoff through recharge pipes/shaft and dug well to augment groundwater during rainy season that can fulfill nearly 70% of groundwater demand maintaining its quality. Beneficiaries are satisfied with governance issues and sustainability of the models.

In Bangladesh, the approach of water sector emphasises on the agenda like infrastructural development to meet the needs, neglecting governance issues in the water management institutions (WMIs) to achieve their sustainable development. However, the Government of Bangladesh (GoB) is committed to work for SDG 2030 by addressing good governance issues in all sphere of its activities. In this context, present study is undertaken to assess the existing water governance status of the WMIs like the Barind Multipurpose Development Authority (BMDA); the Bangladesh Water Development Board (BWDB); the Department of Public Health and Engineering (DPHE); and the Local Government and Engineering Department (LGED) as government agencies; and Development Association for Self-reliance, Communication and Health (DASCOH) is a non-government and non-profit organization selected purposively based on their activities in water sector in the drought-prone water scarce Barind Tract in the north-western part of country. The methodology for governance status assessment includes both quantitative and qualitative approaches; and eight indicators like institutions, transparency, accountability, participation, social equity, environmental integrity, efficiency, and effectiveness are taken into consideration where each indicator includes five sub-indicators. Considering individual performance, the assessment indicated that DASCOH Foundation performs ‘good’, BMDA and LGED show ‘moderate’, while BWDB and DPHE exhibited ‘bad’ performance. However, the overall governance status of WMIs falls under ‘moderate’ category. This result indicates that BWDB and DPHE should look into the governance issue seriously and take a rigorous action plan for its scaling up. On the other hand, BMDA and LGED should be careful about the indicators like transparency, accountability, participation, and social equity. The DASCOH Foundation is performing well by introducing noble concepts to institutionalise the Integrated Water Resource Management (IWRM) under BWA (2013). Finally, there exist gap in governance issues of WMIs in coordination, technical capacity, and transparency in project selection, implementation, and citizen’s participation which should be considered seriously in managing water resources in sustainable manner.

The objectives of the present study were to explore the changes in the water balance components (WBCs) by co-utilizing the discrete wavelet transform (DWT) and different forms of the Mann–Kendall (MK) test and develop a wavelet denoise autoregressive integrated moving average (WD-ARIMA) model for forecasting the WBCs. The results revealed that most of the potential evapotranspiration (PET) trends (approximately 73 %) had a decreasing tendency from 1981–1982 to 2012–2013 in the western part of Bangladesh. However, most of the trends (approximately 82 %) were not statistically significant at a 5 % significance level. The actual evapotranspiration (AET), annual deficit, and annual surplus also exhibited a similar tendency. The rainfall and temperature exhibited increasing trends. However, the WBCs exhibited an inverse trend, which suggested that the PET changes associated with temperature changes could not explain the change in the WBCs. Moreover, the 8-year (D3) and 16-year (D4) periodic components were generally responsible for the trends found in the original WBC data for the study area. The actual data was affected by noise, which resulted in the ARIMA model exhibiting an unsatisfactory performance. Therefore, wavelet denoising of the WBC time series was conducted to improve the performance of the ARIMA model. The quality of the denoising time series data was ensured using relevant statistical analysis. The performance of the WD-ARIMA model was assessed using the Nash–Sutcliffe efficiency (NSE) coefficient and coefficient of determination (R2). The WD-ARIMA model exhibited very good performance, which clearly demonstrated the advantages of denoising the time series data for forecasting the WBCs. The validation results of the model revealed that the forecasted values were very close to actual values, with an acceptable mean percentage error. The residuals also followed a normal distribution. The performance and validation results indicated that models can be used for the short-term forecasting of WBCs. Further studies on different combinations of wavelet analysis are required to develop a superior model for the hydrological forecasting in the context of climate change. The findings of this study can be used to improve water resource management in the highly irrigated western part of Bangladesh.

Demand for irrigation water increases day by day along with meteorological vagaries and extension of irrigated area in the drought-prone Barind area of Bangladesh. This increasing stress on water resource is gradually making the area water scare. The study is aimed at studying the morphometric parameters of the Atrai-Sib river basin in the Barind area and on their relevance in water resource management based on satellite images and SRTM DEM. Computation and delineation of linear and areal aspects of the river basin and its morphometric components reveals that stream order ranges from first to eighth order showing dendritic drainage pattern. The basin represents homogeneity of soil texture; possibility of flash flood after heavy rainfall with low discharge of runoff; and is not largely affected by structural disturbance. Moderate drainage density of the river basin area indicates semipermeable soil lithology with moderate vegetation. Mean bifurcation ratio of the basin is calculated as 3.92 and elongation ratio 0.75, which indicate elongated shape of the river basin with low to moderate relief bounded in the east and west by ‘moderate to steep’ sloping land area. It reveals a flatter peak of runoff flow for longer duration and gravity flow of water. The gentle but undulating slope of the basin represents ‘excellent’ category for groundwater management as the site is favorable for infiltration due to maximum time of runoff water percolation. The east facing slopes of the basin show higher moisture content and higher vegetation than the west-facing slope. The land use pattern of the area shows that major part (95.29%) comes under the cultivated land which will support future river basin development and management. Results obtained from the study would be useful in categorization of river basins for future water resource development and management, and selection of suitable sites for water conservation structures such as check dam, percolation tank, artificial recharge of groundwater through MAR technique etc.

Present research work is carried out in the Atrai–Sib river basin in the drought-prone but agro-based Barind area in the north-west of Bangladesh to delineate the groundwater potential zones using integrated approach of remote sensing (RS) and geographic information system (GIS)-based multi-criteria evaluation. Decreasing trend in rainfall along with increasing population in this drought-prone area calls for a sustainable development of the groundwater resource. The river basin possesses dendritic drainage pattern and major portion of runoff water allows more infiltration to recharge the groundwater and is, therefore, a potential for groundwater occurrence. The gentle to flat river basin is of ‘excellent’ category for groundwater management because of favorable infiltration to maximum time of runoff percolation. Here, seven different thematic layers such as, geomorphology, drainage density, rainfall, lithology, lineament density, slope and land use/ land cover (LULC) are integrated in GIS environment to study groundwater potentiality. Corresponding normalized rates for the classes in a layer and weights for the thematic layers are computed using Saaty’s Analytical Hierarchy Process (AHP), and then aggregated thematic map is prepared using a weighted linear combination (WLC) method. Map-removal and single-parameter sensitivity analysis are used to examine the effects of removing any thematic layer on the groundwater potential zones and to compute effective weight, respectively. About 226 km2 (6% of the study area) is designated as very good groundwater potential zone, whereas that of good, moderate, very poor and poor groundwater potential zones cover 407 km2 (11%), 720 km2 (19%), 997 km2 (26%) and 1418 km2 (38%), respectively. Sensitivity analysis shows that the groundwater potential zonation in the study area is most sensitive to lineament density (mean variation index 2.66), which is the most effective thematic layer in the groundwater potentiality zone (mean effective weight of 27.13%) and supports the need for future river basin development and management. This study can help to identify the groundwater potential zones of this drought-prone area that will lead towards the planning of the integrated water resources management.

The study analyzes drought using Standardized Precipitation Index (SPI) and Mann-Kendall (MK) Trend Test in the context of the impacts of drought on groundwater table (GWT) during the period 1971-2011 in the Barind area, Bangladesh. The area experienced twelve moderate to extreme agricultural droughts in the years 1972, 1975, 1979, 1982, 1986, 1989, 1992, 1994, 2003, 2005, 2009 and 2010. Some of them coincide with El Nino events. Hydrological drought also occurred almost in the same years. However, relationship between all drought events and El Nino is not clear. Southern and central parts of the area frequently suffer from hydrological drought, northern part is affected by agricultural drought. Trends in SPI values indicate that the area has an insignificant trend towards drought, and numbers of mild and moderate drought are increasing. GWT depth shows strong correlation with rainy season SPI values such that GWT regaining corresponds with rising SPI values and vice versa. However, 2000 onwards, GWT depth is continuously increasing even with positive SPI values. This is due to over-exploitation of groundwater and changes in cropping patterns. Agricultural practice in Barind area based on groundwater irrigation is vulnerable to drought. Hence, adaptation measures to minimize effects of drought on groundwater ought to be taken.

The aim of the study is to assess the agricultural drought risk condition in the context of global climate change in the western part of Bangladesh that covers about 45% area of the country for the period of 1960–2011. Drought Index (DI) and Drought Hazard Index (DHI) have been calculated by Markov Chain analysis and that of Drought Vulnerability Index (DVI) from socioeconomic and physical indicators. The DI values show that the northern part in general is more drought-prone, having less crops prospect, whereas the southern part is less drought-prone with high crop potentiality. The probability of extreme drought occurrence increases in recent decades in some parts as a result the drought events become more frequent in the areas. The DHI ranges from 15 to 32, and northern part suffers from more extreme drought hazards than that of southern part. DVI also indicates that northern part is exposed to high to very high drought vulnerability as higher percentage of illiterate people are involved in agricultural practices and high percentage of irrigation to cultivable land, but southern part exposed to moderate to low vulnerability because of low values of vulnerability indicators. Finally, agricultural drought exists at high risk condition in northern part and low in southern parts and 21.63, 26.54 and 29.68% of the area poses very high, high and moderate risk, respectively. So, immediate adaptation measures are needed keeping in mind climate features like rainfall and temperature variability, drought risk and risk ranking to make viable adaptation measures.

Livelihood in agro-based Barind area in northwest Bangladesh is at risk due to moderate-extreme drought impacts. Assessment of water governance status is carried out considering the blue water footprint (WF). Here, the cropping pattern is dominated by rice and the majority of the farmers use groundwater for irrigation. Among crop varieties, Boro rice accounts for the highest WF (3109 l/kg) consuming 70% of water with little economic return, and all crops exceed global WF standards. The performance indicators like transparency, accountability, participation, social equity, environmental integrity, efficiency and effectiveness of government organizations (BMDA, BWDB, DPHE and LGED) and NGOs (DASCOH Foundation) show that the performance of DASCOH Foundation was ‘good’; BMDA and LGED ‘moderate’; while BWDB and DPHE ‘bad’, and should take rigorous action plans for scaling up in these issues. DASCOH Foundation has started to institutionalize IWRM, updating water laws etc. So, appropriate strategies for governance performance due to sustainable resource management should be given priority with enabling environment, institutions, and instruments.

Monitoring and detecting trends of climatic variables like rainfall and temperature are essential for agricultural developments in the context of climate change. The present study has detected trends in annual and cropping seasonal rainfall and temperature data for the period of 1961–2011 using Mann–Kendall (MK) test, Spearman’s rho (SR) test and modified Mann–Kendall test that has been applied to the significant lag-1 serial correlated time series data, and slope has been estimated using Sen’s Slope estimator for twelve meteorological stations located in the western part of Bangladesh covering about 41 % of the country. Almost 71 % trends explored by MK test in annual rainfall are statistically insignificant, and SR test also complies it. The spatial distribution of rainfall trend shows insignificant positive trends in major part of the area. Significant positive trends both by MK test and by SR test at 95 % confidence levels are observed at rates of 8.56, 11.15 and 13.66 mm/year at Dinajpur, Rangpur and Khepupara stations, respectively, and the Kharif season rainfall of these stations also shows significant increasing trends except Dinajpur. On the other hand, significant decreasing trends in annual rainfall are found at Bhola (−11.67 mm/year) and Rajshahi (−5.951 mm/year) stations and decreasing trends in rainfall dominated the Pre-Kharif season over the area. But, 83.33 % of the stations show rising trends in annual mean temperature with significant positive trends (as observed by both MK test and SR test) at Rangpur, Bogra, Faridpur, Jessore and Bhola stations where the rate of changes vary from 0.013 °C/year at Faridpur to 0.08 °C/year at Bhola. Most of the trends in Rabi and Pre-Kharif seasons of mean temperatures are not statistically significant. However, all stations except Barisal show significant rising trends in temperature in Kharif season. To cope with this changing pattern of rainfall and temperature, effective adaptation strategies should be taken to keep up the agricultural production that is related to livelihood of the most people and to ensure the country’s food security.

The aims of this study are to determine and evaluate the spatial and temporal changes in the groundwater table for the period of 1991–2009 and probable causes of changes of water table depth in northwest (NW) Bangladesh. Trends analyses have been done by linear regression, Mann–Kendall Trend Test and Sen’s slope estimator; and spatial analysis by Geographical Information Systems (GIS). The results show decreasing trends in dry and monsoon seasons and annual average groundwater level except a few discrepancies in NW Bangladesh, though the magnitudes of changes very spatially and methodically. Very strong declining trends with high magnitude of changes in all three series that are significant at 99 % confidence level found in the central part of the area where the rate of changes vary from 0.82 to 0.2 m/year in dry season, from 0.67 to 0.2 m/year during monsoon season and 0.6 to 0.1 m/year in annual average time series. Declining trends with low rate of changes are found in the rest of the areas except some pocket areas. The drop of groundwater level is also very high in the central part. Falling trends and drop of groundwater level indicate unsustainable withdrawal of groundwater over the study area. Findings of study indicate rigorous abstraction of groundwater for irrigation, decreasing trend in rainfall and surface geology of the area are attributed to rapid declining trend in groundwater level. Situations will be irreversible if necessary steps are not taken beforehand.

In Bangladesh, agriculture plays a major role in the national economy. In the drought prone Barind area in NW Bangladesh, cropping intensity has increased almost double since late eighties of last century (from 1985) because of the introduction of groundwater irrigation. Long-term behavior of groundwater table (GWT) in the drought prone Barind area has been studied using MAKESENS model in the wake of massive installation of tube-wells. The study reveals that the maximum and minimum depths to GWT during 1991-2010 show on average declining trend of 4.51 m and 4.73 m. The long-term prediction for the period of 2020-50 assuming the current rate of groundwater withdrawal is that the declining trend will be 1.16 to 1.59 and 1.07 to 1.82 times more for maximum and minimum groundwater depths respectively in comparison to the present. The rigorous exploitation of groundwater for irrigation, decreasing rainfall and surface geological attributes lead towards declining trend of GWT. This will hamper the country’s food security and ultimately threaten its socio-economic sustainability. So the appropriate strategies for the management of groundwater resource on a sustainable basis should be the priority for maintaining agricultural productivity.

This study presents implementation of non-linear autoregressive model with exogenous inputs (NARX) of Artificial neural network (ANN), used for groundwater level (GWL) simulation to predict its weekly level up to 52 weeks ahead in selected 14 Permanent Hydrograph Stations (PHSs) in the drought prone Barind Tract in the northwestern part of Bangladesh and is considered to be the first attempt of this type in the country. In this regard, the weekly historical time series climatological data (rainfall, temperature, humidity and evaporation) during 1980–2017 have been used as input variables to forecast GWL. Auto-correlation of GWL time series data to find out the dependent relationship between current GWL to the previous level were carried out and cross-correlation between GWL and rainfall have been used to find out the effectiveness with time. Here GWL is mostly influenced by rainfall having lagged continuation with corresponding peak (max) and trough (min) of rainfall indicating time delayed response of 11.25–14.0 (avg. 12.73) weeks. Analysis before training of ANN reveals that NARX models are good in prediction. Moreover, rainfall has affected by climatological parameters where rainfall is one of the potential input parameter influencing GWL. In recent years, groundwater withdrawals are higher than the rainwater recharge to aquifer due to continuous expansion of irrigated agriculture in the area. Finally, present study as pioneer approach provides significant contributions for groundwater management in resource planning of Bangladesh.

The objectives of the study are to explore the changes in water balance components (WBC) by co-utilizing discrete wavelet transformation (DWT) and different forms of Mann–Kendal (MK) test; and to develop wavelet autoregressive moving average (ARIMA) models for forecasting the WBC. Trend test results reveal that the most of the trends (about 73 %) identified in potential evapotranspiration (PET) show decreasing tendency during the hydrological year 1981–82 to 2012–13 in the western part of Bangladesh, however most of the changes (about 82 %) are insignificant at 5 % significant level. Actual evapotranspiration (AET), annual deficit and annual surplus also show the almost similar tendency. Rainfall and temperature show increasing trends, but WBC show inverse of this tendency and suggesting that traditional concept of changes in PET associated with changes in temperature cannot explain the changes in WBC. Moreover, it is found that generally 8-years (D3) to 16-years (D4) periodic components are the effective components and are responsible for trends found in original data of WBC in western part of Bangladesh. Wavelet denoising of WBC time series has been done to improve the performance of models as actual data affected by noise and show unsatisfactory performances. The quality of denoised data has been ensured by relevant statistical analysis. Performance of wavelet ARIMA models have been assessed by Nash–Sutcliffe Efficiency (NSE) coefficient and coefficient of determination (R2). The obtained results indicate that performances of wavelet ARIMA models of WBC are acceptable to very good and clearly demonstrate the advantages of denoising over actual data. The models validation results reveal that the forecasted values are very close to actual values with acceptable mean percentage error and residuals also follow normally distribution. Performances and validation results indicate that models can be used for short term forecasting of WBC. Further studies on different combinations of wavelet analysis would be facilitated to develop better models for WBC in context of climate change and findings of study can be used to improve water resources management in highly irrigated western part of Bangladesh.

In the salinity affected lower Atrai floodplain aquifer in the NW Bangladesh, geoelectric resistivity survey and hydrochemical analysis are carried out with an aim to identify fresh and saline groundwater zones; investigate the status of salinity; evaluate hydrochemical processes involved and suggest management approaches for irrigation. Here a two-fold aquifer system, inter-layered by silt, clay and silty-clay aquitard and aquiclude is classified as: upper aquifer — spatially affected by salinity of varying degrees; and lower aquifer — generally characterized by high salinity. The aquifer with resistivity values greater than 69 Ωm is safe for irrigation use. Concentrations of major ions vary as: Ca2+>Na+>Mg2+>K+ and HCO3>Cl>NO3>SO42−. Groundwater is dominated by Na-Ca to Ca-Na, HCO3-Cl-SO4, Cl-SO4-HCO3 and Cl-SO42− facies where Ca2+, Mg2+, SO42−, HCO3−, Cl− and NO32− ion concentrations are statistically dominant and water is of Ca-Mg, HCO3-SO4-Cl and NO3 types. Geochemically, groundwater is hard and saline to fresh water type. Salinity increases with depth, but spatially towards the southern part. Groundwater quality is a product of water-rock interaction, direct mixing and marine spraying, or fall-out of airborne marine salts, where silicate weathering is the primary source of bivalent cations. Sediment provenance of alkaline earth silicates and higher concentrations of alkalis are derived from sources other than precipitation. In general partially or fully salinity affected upper and lower aquifers in the area except in its eastern part are not suitable for tubewell irrigation. As groundwater demand for irrigation is increasing, the saline water has progressively invaded relatively fresher parts of the aquifer by upconning. So, special salinity control management approaches can be adopted through engineering techniques such as groundwater abstraction optimization, as also through scientific behavioral approaches like groundwater demand management, salt tolerant crops production. In this context, surface water conservation and rain water harvesting for domestic and irrigational uses are recommended in the salinity affected area.

Present study aims to aid for sustainable management plan of the study area by assessing the potentiality of Integrated Water Resource Management (IWRM) following Bangladesh Water Act (BWA) 2013 and implementing its pilot model through Rain Water Harvesting (RWH) technique as a scientific outcome. The livelihood in the area is at high risk due to drought-situation and expansion of groundwater based irrigated agriculture over the last decade. The stream network and watersheds have been delineated for assessing the potentiality of surface water conservation. The implemented RWH process includes technologically modified dug well recharge and recharge well, runoff water conservation in re-excavated ponds, Kharies along with constructed check dam, and Beels. The annual bimodal distribution of rainfall has high harvesting potentiality during rainy season along with direct runoff amount of 1215 mm. The total harvested amount of rainfall from rooftop, settlement area and cultivated area are 9670869 m3, 145329128 m3 and 730431628 m3 respectively with total amount of 885431625 m3.The total harvested amount of rainfall and runoff water can fulfill 71% of the total water demand of household and agriculture. After implementation of MAR technique situation started to reverse, that is GWT started rising in response to the augmented groundwater recharge artificially. Analyzed physical, chemical and bacteriological parameters of groundwater quality for pre- and post- MAR technique application stages found suitable for drinking purpose. Before implementation of surface water management scheme water was available for three to five months but after implementation it is round the year. Moreover, the implemented RWH schemes and cross dam, reduce pressure on groundwater withdrawal and provide benefits to farmers particularly women for domestic uses, pisciculture, duck rearing etc., pinpoint '4R' principles of IWRM. Beneficiaries are happy about the inclusiveness and sustainability of schemes with most positive attitude for IWRM practice in study area.

Geo-electrical resistivity techniques have been employed in the High Barind as a reconnaissance investigation for the subsurface lithology. Out of 13 upazillas, comprising the Barind tract, Sapahar and Porsha Upazillas, situated in the High Barind are badly affected by water shortage. Vertical electrical soundings (VES) were executed using Schlumberger configuration in different areas taking the current electrode separation up to 170 meters. Direct method technique was employed to evaluate the geo-electric layer such as resistivity and thickness of the discrete layers. The results of the resistivity survey give the subsurface information consisting of three to four layers. The results of geo-electric sounding have been compared with the geological section wherever available. DOI: http://dx.doi.org/10.3329/rujs.v39i0.16540 Rajshahi University J. of Sci. 39, 27-37 (2011)

The annual groundwater recharge and discharge of aquifer of the Sapahar and Porsha Upazillas is estimated by Thiessen polygon method varies from 106.41 to 244 Mm3 and 93.77 to 291 Mm3 respectively. The calculated groundwater recharge of aquifer of the study area shows that the rate of groundwater recharge of aquifer in Porsha Upazilla is higher than that of Sapahar Upazilla and is characterized by very suitable groundwater storage potential. The overall groundwater balance study in the study area indicates that there exists a balance between annual recharge and withdrawal up to 1993 but after period of 1993 discharge exceeds the recharge continuing till today. But hereforth a cumulative annual deficit is found to exist because of progressive annual discharge in Sapahar Upazilla. 23.99 to 42.08 Mm3 of groundwater is discharged by discharging mechanisms. The rest of groundwater is discharged by natural seepage. DOI: http://dx.doi.org/10.3329/rujs.v39i0.16539 Rajshahi University J. of Sci. 39, 11-26 (2011)

The Rajshahi city is the fourth largest metropolitan city in Bangladesh on the bank of the River Padma (Ganges). Here an upper semi-impervious layer overlies aquifer — the source for large-scale groundwater development. The groundwater resource study using Visual MODFLOW modeling shows that recharge occurs mainly due to infiltration of rainfall and urban return flow at low rate, and water level fluctuates seasonally in response to recharge and discharge. Hydraulic connection between river and aquifer which indicates inflow from high river water levels beyond its boundaries. The total groundwater abstraction in 2004 (15000 million liters) is lower than total input to aquifer reveals an ample potentiality for groundwater development with increasing demand. But groundwater shortage (1000 million liter/year) especially in the vicinity of the River Padma in dry season happens due to its increasing use and fall of river water level resulting in reduced inflows and hence decline in groundwater level. The conjunctive use of surface water-groundwater and its economic use will help for sustainable groundwater supply to avoid adverse impact.

The Barind Integrated Area Development Project (BIADP), NW Bangladesh launched in late eighties of last century boosted cropping intensity from 117% in pre-BIADP to about 200% at present. Increasing trend of rainfall for the period 1980-2006 in the southern portion had a positive impact on BIADP, but in the northeastern part, reverse trend is indicated. The groundwater outflow from the central part following the surface gradient is indicative of effluent drainage characteristics. Although rainfall has increased in the southern part, there has been progressive decline in groundwater level due to increase in irrigation demand. In the northern part there has been decline in groundwater level due to less resource potential. The PET, ET crops and net irrigation requirement generally has decreased from pre- to post- Project implementation stages and rainwater has been the supplementary irrigation resource and thus dependency on groundwater has been reduced with exception in northwestern part. While the southern part is marching towards humid condition, north is creeping towards semi-aridity. Proper groundwater resource management with ecological balance is warranted for the sustainability of BIADP.

The groundwater recharge potentiality in Barind Tract in Rajshahi district, Northwest Bangladesh was studied based on Geographical Information System (GIS) and Remote Sensing technique. In this connection satellite images (Landsat 7 ETM and SPOT) and aerial photos were subjected to several treatment processes using softwares like ERDAS Imagine and ESRI’s Arc View. Thus various thematic maps have been prepared for drainage density, lineaments, lithology and land cover/use that allowed deciding their interactive effect. In the present study, the degree of effect was determined for each factor to assess the total groundwater recharge potentiality for two categories (moderate to low). The resultant map shows that 85% of the area has low, and rest has moderate groundwater recharge potentiality. Finally only 8.6% of the total average annual precipitated water (1685mm) percolates into subsurface and ultimately contributes to recharge the groundwater.

Hydrochemistry in parts of the Lower Tista Floodplain in northwest Bangladesh is dominated by alkalies and weakly acid, having highest concentration of sodium cations and bicarbonate anions respectively. Groundwater is characterized by sodium-calcium and sodium-potassium cation and bicarbonate-chloride-sulphate anion facies, and genetically ‘normal chloride’, ‘normal sulphate’, and ‘normal carbonated’ type, and soft to saline. Based on electrical conductivity values, the area is divided into northern fresh and southern saline groundwater zone, and values like salinity, Na%, SAR, and RSC and a good correlation between Na+ and Cl−, and Cl− and salinity reveals increasing salinity with depth indicating a mixing of fresh and saline bodies due to marine transgression (?) during Holocene period in the Bengal delta. The rock weathering is likely to affect the groundwater quality by dolomite dissolution and calcium precipitation, representing reverse softening process and is brine seawater. Water extracted from shallow zone (from 20 to 30 m) has suitability for drinking purpose, livestock consumption and irrigation purposes, and partially suitable for industrial use, but that from deeper zone (from 30 to 50 m) is generally poor and unsuitable especially for irrigation purposes with low alkali and moderate to high salinity hazard. So groundwater can be used for irrigation in the area of fine textured soil with proper management practices.

Morphometric analysis of major watersheds based on satellite images using hydrological module of ARC GIS software in the drought prone Barind Tract in the north-western part of Bangladesh has been carried out for its relevance in the water resource management. Here meteorological and hydrological drought effects increase day by day along with demand for groundwater irrigation, turning the area into acute agricultural drought condition. The studied watersheds have stream orders ranging from 1st to 6th, show dendritic drainage pattern, and represent homogeneity of soil texture; possibility of flash flood after heavy rainfall with low discharge of runoff; and not largely affected by structural disturbance. The moderate drainage density indicates semi-permeable soil lithology with moderate vegetation. Elongated shape watersheds are with low to moderate relief and are bounded in the east by land area of the Barind Tract of moderate to steep slope. It reveals a flatter peak of runoff flow for longer duration and gravity flow of water. Flat to gentle but undulating slope of the watersheds represent good category for water resource management owing to favorable site for infiltration due to maximum time of runoff water percolation. The east facing slopes of the watersheds show higher moisture contents and higher vegetation. The major part of the watersheds comes under cultivated land which supports the future basin development and management for water resource. Finally, present study would be useful in categorization of watersheds for future water resource development and management, and selection of suitable sites for water conservation structures like check dam, percolation tank etc., and artificial recharge of groundwater through MAR technique.