Volume 11, Number 02, 2016

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Author: search.filters.author.Zahid, Anwar

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    Evaluation of the aquifer system and groundwater quality of the north-western districts of Bangladesh for development potential
    (© 2016 Published by BRAC University, 2016) Islam, Kamrul; Rahman, M. Saidur; Ali, M. Hazrat; Hossain, A.F.M. Afzal; Alam, M. Jahangir; Zahid, Anwar
    Considering the comparatively low agricultural production in the area, assessment of the potential of increased agricultural production in Panchagarh, Thakurgaon, Dinajpur and Joypurhat districta was undertaken, through optimum utilization of available water resources. Physiographically, Thakurgaon, Dinajpur and Panchagarh areas are mostly under the Old Himalayan Piedmont Plain and Joypurhat and some areas of Dinajpur are under the Tista floodplain and Barind Tract. To explore the aquifer system in the area, a total of 15 new test drillings were cnoducted down to the maximum depth of 300 m and 50 observation wells were selected for observing the groundwater level trend. Groundwater samples were collected from 20 locations for analysis and interpretation of important physicochemical parameters. The important constitoenta that influence the water quality for inigation were calculated using standard equations. From the spatial distribution of the borelogs from northwest to southeast reveals that down to the investigated depth of 300m the aquifer system is hydraulically connected regionally though one or more aquitards are encountered at local level. The maximum depth to groundwater table below ground surface is between 4.0 to 12.0 m doring dry month of April. The groundwater table lowers beyund the suction limit (7.5 m) of no. 6 hand tube wells (HTW) in some parts of the study area. In geneml, groundwater quality of the areas is suitable both for domestic and agricultural uses except at a few localities where iron concentration exceeded the allowable limit. The most of the study area has potentiality for groundwater development having higher rainfall and recharge potential. However, when usable recharge is considered at base condition, shortage of groundwater is observed in few areas and no further installation of irrigation TWs is recommended in those areas.
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    Context specific safe water supply technologies for vulnerable climatic and geomorphologic areas of Bangladesh
    (© 2016 Published by BRAC University, 2016) Zahid, Anwar; Rashid, S.M.A.; Miah, M.A. Salam; Halder, Joseph; Islam, M.T.; Tazneen, Farhana
    The detection of arsenic in shallow groundwater threatens groundwater based water supply in Bangladesh. Seawater encroachment in coastal aquifers is another major problem for the availability of fresh water. On the other hand, surface water source is not suitable in many parts of the country. In addition, vu1nerable climatic conditions and anticipated impact of climate change arc putting more stress on the sustainable development of safe water resources. Therefore, one technology is not suitable for all areas due to different hydro meteorological conditions. The aim of this paper is to determine sustainable context-specific water supply technologies considering the climatic hazard and other vu1nerabilities in 5 different hard to reach (HtR) areas, which are (a) drought prone, (b) flood prone, (c) char (sand bar), (d) coastal and (e) haor (swamp) areas. It is found from the study that more activities and effort is needed to ensure the water supply facilities for all, mainly in the HtR areas. Still expansion and improvement of the water supply services is required to satisfy the basic needs in these areas. Proper maintenance and monitoring of existing appropriate technologies arc also important for sustainable use. Guidelines and user manuals need to be prepared as a tool to standardized procedures for installation and easy maintenance of technologies.
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    Determining sources of groundwater salinity in the multi-layered aquifer system of the bengal delta, Bangladesh
    (© 2016 Published by BRAC University, 2016) Zahid, Anwar; Rahman, Aminur; Hassan, M. Rashidul; Ali, M. Hazrat
    The study area lies on the coastal belt of the Bengal Delta, southern Bangladesh. This study bas been condocted to deteonine salinity sources in the multi-layered aquifers of the Bengal Delta. Dissolved major ions including chloride (Cr) and brontide (Br) were measured in groundwater of the coastal areas of Bangladesh to assess the source(s) of salinity. Ionic concentrations of 48 groundwater samples were analyzed for this study; samples were collected from observation wells installed at different depths down to 336 m. The major ion trends of the upper (<200 m deep) Sodium (Na')-Chloride (Cr) groundwater type is defined as Na+> Calcium (Ca2l> Magnesium (Mg'"')> Potassium (K"') and Cl> Bi-carbonate (HC03 )> Sulfate (So,'-). The deep groundwater (201-336 m deep) bas ionic trend of Na+>Ca2+>Mg'+>K+ and HC03>Cl>So.'·. The shallow groundwater (<200 m deep) of the south central coast bas Br:Cr ratios between 0.00234 and 0.00354 and correspondiog Cr:Br molar ratios between 635.51 and 959.78, which indicates that seawater from the ocean is the principal source of chloride in the upper aquifers with the mixture of fresh water mainly recharged from monsoon rain. At some locations in the south-central coast, seawater is also the principal source of the salinity in deep groundwater, within the depth ranging from 201 to 336 m. Elevated chloride concentration might be due to the entrapment of relict seawater in the sediment during Holocene transgression.