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Dhaka city has emerged as the fastest-growing megacity, having more than 20 million inhabitants, with a growth rate of 3.62%. Unplanned and rapid urbanization, coupled with exponential population growth, has significantly altered the groundwater dynamics in Dhaka city. This study concentrates on the evolution of long-term piezometric heads of the Upper Dupi Tila aquifer (UDA) and the Middle Dupi Tila aquifer (MDA) based on long-term hydrographs, piezometric maps and synthetic graphical overviews of piezometric trends. Due to over-exploitation, the piezometric level (PL) has declined deeper than −85 and −65 m PWD (Public Works Department reference datum) in UDA and MDA, respectively. The highest rate of decline was observed in the south-central to southeastern parts of the city both in UDA (4.0 m/year) and MDA (5.74 m/year). The results clearly show that the rates of decline in PL vary from 2.25 to 5.74 m/year in both aquifers of the city, and urban expansion has greatly affected the shape and extent of the depression cone over the past four decades. The magnitudes of the depression cones in both aquifers seem to pose a considerable threat to groundwater resources, indicating that the current exploitation is not sustainable at all.
Mazeda Islam; Marc Van Camp; Delwar Hossain; Mizanur Rahman Sarker; Shahina Khatun; Kristine Walraevens. Impacts of Large-Scale Groundwater Exploitation Based on Long-Term Evolution of Hydraulic Heads in Dhaka City, Bangladesh. Water 2021, 13, 1357 .
AMA StyleMazeda Islam, Marc Van Camp, Delwar Hossain, Mizanur Rahman Sarker, Shahina Khatun, Kristine Walraevens. Impacts of Large-Scale Groundwater Exploitation Based on Long-Term Evolution of Hydraulic Heads in Dhaka City, Bangladesh. Water. 2021; 13 (10):1357.
Chicago/Turabian StyleMazeda Islam; Marc Van Camp; Delwar Hossain; Mizanur Rahman Sarker; Shahina Khatun; Kristine Walraevens. 2021. "Impacts of Large-Scale Groundwater Exploitation Based on Long-Term Evolution of Hydraulic Heads in Dhaka City, Bangladesh." Water 13, no. 10: 1357.
The hydrogeochemical processes in the multilayer aquifers of southwest (SW) coastal area of Bangladesh provide important information for quantifying hydrochemical differences between different aquifers. Hydrogeochemical processes affecting groundwater chemistry in this coastal area have been evaluated by interpreting conventional plots, ionic delta, HFE-diagram, stable isotopes and geochemical modelling. The median TDS distribution of the aquifers has an increasing trend from below 1000 mg/l in the deep aquifer (DA) to 2622 mg/l in lower shallow aquifer (LSA) and 7012 mg/l in upper shallow aquifer (USA). Na+ is the dominant cation in all the aquifers. HCO3− is the dominant anion in DA with high median concentration (495 mg/l), which is more than double than that in LSA (214 mg/l) and USA (159 mg/l). The groundwater in the DA is freshened NaHCO3+ type due to cation exchange process that enhances second stage of calcite dissolution. Few NaCl+ type DA waters found in the SW corner of the study area indicate the presence of connate water confined in the inter-basin during the Holocene transgression. The stable isotopes indicate that the DA waters have been deposited during warmer periods. In contrast, both the LSA and USA are dominated by NaCl- type water; some CaCl- type waters have also been found in these aquifers, indicating salinization. The salinization processes consist of infiltration of redissolved evaporite salts, reverse cation exchange, and mixing with marine influenced flood water. Thus, the knowledge of different processes controlling freshening and salinization will help properly manage and preserve the environmental characteristics in the aquifer systems of SW Bangladesh as well as similar complex coastal geological settings.
Mizanur Rahman Sarker; Marc Van Camp; Delwar Hossain; Mazeda Islam; Nasir Ahmed; Masud Karim; Abdul Quaiyum Bhuiyan; Kristine Walraevens. Groundwater salinization and freshening processes in coastal aquifers from southwest Bangladesh. Science of The Total Environment 2021, 779, 146339 .
AMA StyleMizanur Rahman Sarker, Marc Van Camp, Delwar Hossain, Mazeda Islam, Nasir Ahmed, Masud Karim, Abdul Quaiyum Bhuiyan, Kristine Walraevens. Groundwater salinization and freshening processes in coastal aquifers from southwest Bangladesh. Science of The Total Environment. 2021; 779 ():146339.
Chicago/Turabian StyleMizanur Rahman Sarker; Marc Van Camp; Delwar Hossain; Mazeda Islam; Nasir Ahmed; Masud Karim; Abdul Quaiyum Bhuiyan; Kristine Walraevens. 2021. "Groundwater salinization and freshening processes in coastal aquifers from southwest Bangladesh." Science of The Total Environment 779, no. : 146339.
Groundwater development in coastal aquifers of southwest Bangladesh is challenged by both natural and anthropogenic activities resulting in a landward migration of marine waters and increase in the risk of seawater intrusion. In some cases, infiltration of dissolved evaporite salts in the shallow aquifer and presence of connate water in the deep aquifer (DA) are the sources of groundwater salinity other than modern seawater intrusion. A detail investigation of these sources is imperative for a sustainable development and management of coastal aquifers. This work investigates the hydrogeochemical processes affecting groundwater chemistry by interpreting conventional plots, ionic delta, HFE-diagram, stable isotopes, and geochemical modelling. There are three hydrogeological units delineated in this area: upper shallow aquifer (USA) (<100 m bgl), lower shallow aquifer (LSA) (100-200 m bgl) and DA (below 200 m bgl). The hydrochemistry data reveal that the median values of total dissolved solids of the aquifers have a decreasing trend from top to bottom: USA with 7012 mg/l, LSA with 2622 mg/l and DA with 787 mg/l. Sodium is the dominant cation in all waters. The dominant anion in DA is HCO3-, but in shallow aquifers Cl-. The main water type based on the classification of Stuyfzand (1989) is the brackish to saline NaCl type in the shallow aquifers. The Br-/Cl- ratio and relatively enriched δ18O values in these NaCl waters suggest an origin derived from evaporate dissolution. Reverse cation exchange during intrusion, replacing Na+ with Ca2+, results in CaCl and CaMix water types. These waters infiltrate into the LSA. The water in the DA is mainly fresh NaHCO3+ type which originated by cation exchange from infiltrating fresh water. Ca2+ was replaced by Na+ due to the cation exchange, the water became undersaturated with respect to calcite and secondary calcite dissolution caused elevated bicarbonate concentrations. Near the present-day shoreline and at larger depths, the NaHCO3+ type water mixes with connate water, increasing salinity. The enriched δ18O values in the DA suggest an origin in a warmer climate, implying that this water has infiltrated a long time ago, much farther inland, probably during the Holocene climatic optimum. It can be expected that the salinization of the shallow aquifers will continue to increase if evaporite deposition and seasonal flooding occur. For a sustainable use of the groundwater resource in this coastal region and to prevent from even further worsening of water quality in its shallow aquifers, it is advised to develop future exploitations in the DA.
Key words: Groundwater chemistry; Stable isotope; Evaporite; Cation exchange; Calcite dissolution.
Mizanur Rahman Sarker; Marc Van Camp; Delwar Hossain; Mazeda Islam; Abdul Quaiyum Bhuiyan; Ariful Ahsan; George Bennett; Kristine Walraevens. Understanding the Hydrogeochemical Evolution of Groundwater in Coastal Aquifers of Southwest Bangladesh. 2021, 1 .
AMA StyleMizanur Rahman Sarker, Marc Van Camp, Delwar Hossain, Mazeda Islam, Abdul Quaiyum Bhuiyan, Ariful Ahsan, George Bennett, Kristine Walraevens. Understanding the Hydrogeochemical Evolution of Groundwater in Coastal Aquifers of Southwest Bangladesh. . 2021; ():1.
Chicago/Turabian StyleMizanur Rahman Sarker; Marc Van Camp; Delwar Hossain; Mazeda Islam; Abdul Quaiyum Bhuiyan; Ariful Ahsan; George Bennett; Kristine Walraevens. 2021. "Understanding the Hydrogeochemical Evolution of Groundwater in Coastal Aquifers of Southwest Bangladesh." , no. : 1.
Dhaka city with an area of about 306 Km2 and a population of more than 20 million is located in the central part of Bangladesh. Immense and prolonged groundwater abstraction due to rapid unplanned urbanization and population blast in this city have led to significant decline in groundwater level in the last three decades. 78% of the supplied water comprises groundwater from the Dupi Tila Sandstone aquifer system. Hydrogeological and geophysical data aided to the delineation of three different aquifers (based on lithology): Upper Dupi Tila aquifer (UDA), Middle Dupi Tila aquifer (MDA) and Lower Dupi Tila aquifer (LDA). The evaluation of long-term hydrographs, piezometric maps and synthetic graphical overviews of piezometric trends in both the UDA and MDA depicts that the rate of dropping of groundwater level (GWL) is very substantial. Massive pumping in the city has altered its natural hydrologic system. The groundwater level has dropped on average 2.25 m/year and 2.8 m/year in UDA and MDA, respectively, in the whole city in 2018, whereas the average rate of decline in the center of the depression cone during this time was 4.0 m/year and 5.74 m/year respectively. Presently, the groundwater level elevation has declined to levels lower than -85 and -65 m PWD in UDA and MDA, respectively. The changes in pattern and magnitude of depression cones in UDA and MDA are directly associated with the city expansion and number of deep tube wells installed over a certain period in particular parts of the city. The depletion of GWL from 1980 to 2018 is very notable. There is only limited vertical recharge possible in the UDA and MDA as they are semi-confined aquifers, and only lateral flow mostly in the UDA and MDA from the surroundings is to be expected. In this regard the long-term management of groundwater resources in Dhaka city is urgently needed, otherwise the condition may go beyond control.
Key words: Groundwater abstraction, city expansion, hydrographs, piezometric maps, GWL decline, depression cone.
Mazeda Islam; Marc Van Camp; Delwar Hossain; Mizanur Rahman Sarker; Shahina Khatun; Kristine Walraevens. The impact of urbanization and rapid population growth on the groundwater regime in Dhaka city, Bangladesh. 2021, 1 .
AMA StyleMazeda Islam, Marc Van Camp, Delwar Hossain, Mizanur Rahman Sarker, Shahina Khatun, Kristine Walraevens. The impact of urbanization and rapid population growth on the groundwater regime in Dhaka city, Bangladesh. . 2021; ():1.
Chicago/Turabian StyleMazeda Islam; Marc Van Camp; Delwar Hossain; Mizanur Rahman Sarker; Shahina Khatun; Kristine Walraevens. 2021. "The impact of urbanization and rapid population growth on the groundwater regime in Dhaka city, Bangladesh." , no. : 1.
Nowadays developing countries around the globe have been undergoing rapid industrialization which is eventually responsible for environmental contamination. For proper assessment of the level of pollution and the proper application of remediation measures, it is imperative to know the pristine geochemistry of the system. In that regard, environmental-geochemistry of a southern part (Rampal: potential site of rapid industrialization) of Bangladesh, has been investigated for elemental abundances, natural radioactivity and physicochemical records of environmental compartments (soil, sediments, river-water). Nuclear analytical techniques such as instrumental neutron activation analysis, energy dispersive X-ray fluorescence, gamma spectrometry were used for soil sample study whereas atomic absorption spectroscopy, UV–vis spectrophotometer etc. were used for water sample analysis. Twenty six elemental abundances (Na, Al, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Cu, Zn, Ga, As, Rb, Sr, Y, Zr, Sb, Cs, Ba, Hf, Ta, W, Pb) including three naturally occurring radionuclides (226Ra, 232Th, 40K) in soil samples and six elemental concentrations (Cu, Zn, Fe, Mn, Cd, Pb), four anionic concentrations (NO3-, SO4-2, PO4-3,Cl-) and four physicochemical parameters (total-alkalinity, total-hardness, electrical-conductivity, pH) of river water were investigated in this study. Along with the experimental data, statistical analysis, several environmental indices (geo-accumulation index, enrichment factor, pollution load index, Potential ecological risk index) and radiological health related indices (radium equivalent activity, radiation hazard index, absorbed dose rate, annual effective dose rate) have been identified for comprehensive assessment of our study site. This study reveals that Rampal receives trivial anthropogenic impact and possesses insignificant ecological and radiological health hazards.
Rahat Khan; Shohel Parvez; Yeasmin Nahar Jolly; Abu Haydar; Ferdous Alam; Mst. Afifa Khatun; Mizanur Rahman Sarker; Ahosan Habib; Umma Tamim; Sopan Das; Shahnaz Sultana; Mohammad Amirul Islam; Kamrun Naher; Debasish Paul; Shirin Akter; Harunor Rashid Khan; Farzana Nahid; Roksana Huque; Mohammad Rajib; Syed Mohammod Hossain. Elemental abundances, natural radioactivity and physicochemical records of a southern part of Bangladesh: Implication for assessing the environmental geochemistry. Environmental Nanotechnology, Monitoring & Management 2019, 12, 100225 .
AMA StyleRahat Khan, Shohel Parvez, Yeasmin Nahar Jolly, Abu Haydar, Ferdous Alam, Mst. Afifa Khatun, Mizanur Rahman Sarker, Ahosan Habib, Umma Tamim, Sopan Das, Shahnaz Sultana, Mohammad Amirul Islam, Kamrun Naher, Debasish Paul, Shirin Akter, Harunor Rashid Khan, Farzana Nahid, Roksana Huque, Mohammad Rajib, Syed Mohammod Hossain. Elemental abundances, natural radioactivity and physicochemical records of a southern part of Bangladesh: Implication for assessing the environmental geochemistry. Environmental Nanotechnology, Monitoring & Management. 2019; 12 ():100225.
Chicago/Turabian StyleRahat Khan; Shohel Parvez; Yeasmin Nahar Jolly; Abu Haydar; Ferdous Alam; Mst. Afifa Khatun; Mizanur Rahman Sarker; Ahosan Habib; Umma Tamim; Sopan Das; Shahnaz Sultana; Mohammad Amirul Islam; Kamrun Naher; Debasish Paul; Shirin Akter; Harunor Rashid Khan; Farzana Nahid; Roksana Huque; Mohammad Rajib; Syed Mohammod Hossain. 2019. "Elemental abundances, natural radioactivity and physicochemical records of a southern part of Bangladesh: Implication for assessing the environmental geochemistry." Environmental Nanotechnology, Monitoring & Management 12, no. : 100225.
Attempt has been made to find the relationship between the basin groundwater flow and the current water chemistry of south-western part of Bangladesh considering their lithological distribution and aquifer condition. The correlation of water chemistry and basin groundwater flow is depicted in the conceptual model. The water-types of shallow groundwater are predominantly Mg-Na-HCO3 and Ca- Mg-Na-HCO3 type. In the deep aquifer of upper delta plain is predominately Na-Cl, Ca-HCO3 and Mg- HCO3 type. In the lower delta plain Na-Cl type of water mainly occurs in the shallow aquifer and occasionally Ca-HCO3, Ca-Mg-Na-HCO3 and Mg-HCO3 type may also occur in shallow aquifer of the eastern part of lower delta plain which could have originated from the recent recharge of rain water. Na- Cl type water is also found in the deep aquifer of lower delta plain. The origin of Na-Cl type water in the deep aquifer of lower delta part might be connate water or present day sea water intrusion. Fresh water occurring in the deep aquifer in the lower delta area is mostly of Mg-Ca-HCO3 and Na-HClO3 types. This type of water originate from intermediate or deep basin flow from the northern part of Bangladesh. The probable source of deep groundwater is Holocene marine transgression (Khan et al. 2000) occurred in 3000–7000 cal years BP and the deep groundwater of Upper Delta plain and Lower Delta plain is clearly influenced by deep basin flow coming from north part of BangladeshJournal of Bangladesh Academy of Sciences, Vol. 42, No. 1, 41-54, 2018
Shahpara Sheikh Dola; Khairul Bahsar; Mazeda Islam; Mizanur Rahman Sarker. Hydrogeological Classification and the Correlation of Groundwater Chemistry with Basin Flow in the South-Western Part of Bangladesh. Journal of Bangladesh Academy of Sciences 2018, 42, 41 -54.
AMA StyleShahpara Sheikh Dola, Khairul Bahsar, Mazeda Islam, Mizanur Rahman Sarker. Hydrogeological Classification and the Correlation of Groundwater Chemistry with Basin Flow in the South-Western Part of Bangladesh. Journal of Bangladesh Academy of Sciences. 2018; 42 (1):41-54.
Chicago/Turabian StyleShahpara Sheikh Dola; Khairul Bahsar; Mazeda Islam; Mizanur Rahman Sarker. 2018. "Hydrogeological Classification and the Correlation of Groundwater Chemistry with Basin Flow in the South-Western Part of Bangladesh." Journal of Bangladesh Academy of Sciences 42, no. 1: 41-54.
The study area is located in the central part of Bangladesh. The aims of this study were to explain the hydrogeological characteristics of aquifers and evaluate the groundwater potentiality. The borehole logs revealed three types of zones: upper aquitard (low permeability clays, silty clays & silts), upper aquifer (very fine sand to fine sand) and lower aquifer (medium to coarse sands and gravels). Both aquifer waters are mainly Ca-Mg-HCO3 type. Except arsenic (As), most of the ions of both aquifer waters are within the limit of drinking standard of WHO (2004) and Bangladesh (DoE, 1997). Arsenic concentrations of upper aquifer exceed both the WHO (10 μg/l) and Bangladesh standard (50 μg/l) and for lower aquifer exceed only WHO standard. Waters of both aquifers in north western and central part of the study area show high arsenic concentration due to lack of continuous impermeable layer between them as revealed from borelog data. Water quality index map also indicates that north western and central part is not suitable for groundwater development because of inferior quality. The average δ18O values for upper and lower aquifer waters are isotopically enriched compared to river water (~10.08‰). Similar isotopic composition of upper (~4.77‰) and lower aquifer waters (~5.50‰) indicates both waters were mixed in the past and mixing may be continued in the future. The mixing may be preferentially from the upper aquifer to lower aquifer because of water abstraction, lack of impermeable layer and high permeability of the upper aquifer etc. Therefore, the potentiality of the lower aquifer may not be suitable for large-scale groundwater development project without any mitigation measure.Journal of Bangladesh Academy of Sciences, Vol. 42, No. 1, 25-40, 2018
Mazeda Islam; Khairul Bashar; Nasir Ahmed; Golam Rasul; Sahadat Hossain; Mizanur Rahman Sarker. Hydrogeologic Characteristics and Groundwater Potentiality of Lower Aquifer of Singair Upazila, Manikganj District, Bangladesh. Journal of Bangladesh Academy of Sciences 2018, 42, 25 -40.
AMA StyleMazeda Islam, Khairul Bashar, Nasir Ahmed, Golam Rasul, Sahadat Hossain, Mizanur Rahman Sarker. Hydrogeologic Characteristics and Groundwater Potentiality of Lower Aquifer of Singair Upazila, Manikganj District, Bangladesh. Journal of Bangladesh Academy of Sciences. 2018; 42 (1):25-40.
Chicago/Turabian StyleMazeda Islam; Khairul Bashar; Nasir Ahmed; Golam Rasul; Sahadat Hossain; Mizanur Rahman Sarker. 2018. "Hydrogeologic Characteristics and Groundwater Potentiality of Lower Aquifer of Singair Upazila, Manikganj District, Bangladesh." Journal of Bangladesh Academy of Sciences 42, no. 1: 25-40.
In the coastal region of Bangladesh, groundwater is mainly used for domestic and agricultural purposes, but salinization of many groundwater resources limits its suitability for human consumption and practical application. This paper reports the results of a study that has mapped the salinity distribution in different aquifer layers up to a depth of 300 m in a region bordering the Bay of Bengal based on the main hydrochemistry and has investigated the origin of the salinity using Cl/Br ratios of the samples. The subsurface consists of a sequence of deltaic sediments with an alternation of more sandy and clayey sections in which several aquifer layers can be recognized. The main hydrochemistry shows different main water types in the different aquifers, indicating varying stages of freshening or salinization processes. The most freshwater, soft NaHCO3-type water with Cl concentrations mostly below 100 mg/l, is found in the deepest aquifer at 200–300 m below ground level (b.g.l.), in which the fresh/saltwater interface is pushed far to the south. Salinity is a main problem in the shallow aquifer systems, where Cl concentrations rise to nearly 8000 mg/l and the groundwater is mostly brackish NaCl water. Investigation of the Cl/Br ratios has shown that the source of the salinity in the deep aquifer is mixing with old connate seawater and that the saline waters in the more shallow aquifers do not originate from old connate water or direct seawater intrusion, but are derived from the dissolution of evaporite salts. These must have been formed in a tidal flat under influence of a strong seasonal precipitation pattern. Long dry seasons with high evaporation rates have evaporated seawater from inundated gullies and depressions, leading to salt precipitation, while subsequent heavy monsoon rains have dissolved the formed salts, and the solution has infiltrated in the subsoil, recharging groundwater.
Mizanur Rahman Sarker; Marc Van Camp; Mazeda Islam; Nasir Ahmed; Kristine Walraevens. Hydrochemistry in coastal aquifer of southwest Bangladesh: origin of salinity. Environmental Earth Sciences 2018, 77, 39 .
AMA StyleMizanur Rahman Sarker, Marc Van Camp, Mazeda Islam, Nasir Ahmed, Kristine Walraevens. Hydrochemistry in coastal aquifer of southwest Bangladesh: origin of salinity. Environmental Earth Sciences. 2018; 77 (2):39.
Chicago/Turabian StyleMizanur Rahman Sarker; Marc Van Camp; Mazeda Islam; Nasir Ahmed; Kristine Walraevens. 2018. "Hydrochemistry in coastal aquifer of southwest Bangladesh: origin of salinity." Environmental Earth Sciences 77, no. 2: 39.
Groundwater of Chapai Nawabganj town has been studied using hydrogeological, hydrochemical and environmental isotope (?18O, ?2H, ?13C, 3H and 14C) data. Aquifer underneath the study area is divided into unconfined to semi-confined Holocene alluvial floodplain aquifer and confined Plio-Pleistocene Dupi Tila sandstone aquifer. Chemical composition of groundwater is characterized by high concentrations of Mg2+, Na+, Ca2+, HCO3-, FeTotal, and low concentrations of Mn2+, NO3 - and PO4 3-. Groundwater samples are mainly Mg-Ca-HCO3 and Na-Mg-Ca-HCO3 types and Na-Mg-Ca-Cl-HCO3 type of water is also found at some places. Based on Cl- and SO42- concentrations groundwater is normal chloride and normal sulphate water, respectively. In terms of SAR and EC values water is excellent for irrigation purpose. The isotopic composition also suggests some segregation of groundwater from the different aquifers and indicates different ages of recharge. DOI: http://dx.doi.org/10.3329/jbas.v38i2.21338 Journal of Bangladesh Academy of Sciences, Vol. 38, No. 2, 131-142, 2014
Zakir Hossain; Khairul Bashar; Ratan Kumar Majumder; Mazeda Islam; Mizanur Rahman Sarker. Hydrogeological investigations of Chapai Nawabganj town of Nawabganj district, North-West Bangladesh using isotope and other techniques. Journal of Bangladesh Academy of Sciences 2014, 38, 131 -142.
AMA StyleZakir Hossain, Khairul Bashar, Ratan Kumar Majumder, Mazeda Islam, Mizanur Rahman Sarker. Hydrogeological investigations of Chapai Nawabganj town of Nawabganj district, North-West Bangladesh using isotope and other techniques. Journal of Bangladesh Academy of Sciences. 2014; 38 (2):131-142.
Chicago/Turabian StyleZakir Hossain; Khairul Bashar; Ratan Kumar Majumder; Mazeda Islam; Mizanur Rahman Sarker. 2014. "Hydrogeological investigations of Chapai Nawabganj town of Nawabganj district, North-West Bangladesh using isotope and other techniques." Journal of Bangladesh Academy of Sciences 38, no. 2: 131-142.