Environmental impact assessment on water quality deterioration caused by the decreased Ganges outflow and saline water intrusion in south-western Bangladesh
This paper deals with an environmental impact assessment of low water flow in the River Ganges during a dry period at the Khulna and Mongla port areas in south-western Bangladesh. Large-scale surface water withdrawal in India after commissioning the Farakka Barrage causes a drastic fall in the Gange...
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Veröffentlicht in: | Environmental geology (Berlin) 2000-12, Vol.40 (1-2), p.31-40 |
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Sprache: | eng |
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Zusammenfassung: | This paper deals with an environmental impact assessment of low water flow in the River Ganges during a dry period at the Khulna and Mongla port areas in south-western Bangladesh. Large-scale surface water withdrawal in India after commissioning the Farakka Barrage causes a drastic fall in the Ganges low-flow condition within the Bangladesh territory during every dry period. The average lowest discharge in the Ganges is 552 m super(3)/s, which is about 73% less than that in the pre-Farakka time. This has caused the deterioration of both surface and groundwater quality of the study area. Salinity is the principal cause of water quality degradation in the area. Present observation shows that the surface water of the area is sulphate-chloride dominated, which signifies high salinity whereas the groundwater is categorized as of medium to high salinity. To maintain the Rupsa River's maximum salinity below 1000 mu S/cm the discharge in the Ganges should be similar to 1500 m super(3)/s, whereas that at Garai basin is similar to 10 m super(3)/s. If this present situation continues it will be a crippling blow to the environment of the area in the long term. An integrated multidisciplinary approach to hydrogeological research is urgently required to salvage the area from further deterioration. |
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ISSN: | 0943-0105 1432-0495 |
DOI: | 10.1007/s002540000152 |