Effect on water resources from upstream water diversion in the Ganges basin

Bangladesh faces at least 30 upstream water diversion constructions of whic h Farakka Barrage is the major one. The effects of Farakka Barrage on water resources, socioeconomy, and culture have been investigated downstream in the basins of the Ganges and its distributaries. A diversion of up to 60% o f the Ganges water over 25 yr has cansed (i) reduction of water in surface water resources, (ii) increased dependence on ground water, till) destructi on of the breeding and raising grounds for 109 species of Gangetic fishes a nd other aquatic species and amphibians, (iv) increased malnutrition, (v) d eficiency in soil organic matter content, (vi) change in the agricultural p ractices, (vii) eradication of inland navigable routes, (viii) outbreak of waterborne diseases, (ir) loss of professions, and (x) obstruction to relig ious observances and pastimes. Further, arsenopyrites buried in the prebarr age water table have come in contact with air and formed watersoluble compo unds of arsenic Inadequate recharging of ground water hinders the natural c leansing of arsenic, and threatens about 75 000 000 lives who tire likely t o use water contaminated with up to 2 mgn of arsenic. Furthermore, the depl etion of surface water resources has caused environmental heating and cooli ng effects. Apart from these effects, sudden releases of water by the barra ge during the flood season cause devestating floods. In consideration of su ch a heavy toll, for the areas downstream, strict international rules have to be laid down to preserve the riparian ecosystems.