The future adequacy of freshwater resources is difficult to assess, owing to a complex and rapidly changing geography of water supply and use. Numerical experiments combining climate model outputs, water budgets, and socioeconomic information along digitized river networks demonstrate that (i) a large proportion of the world's population is currently experiencing water stress and (ii) rising water demands greatly outweigh greenhouse warming in defining the state of global water systems to 2025.

The basin area of the Ganges river in Bangladesh is extremely dependent on a regular water supply from upstream to meet requirements for agriculture, fisheries, navigation, salinity control, domestic and industrial sectors. In 1975 India commissioned a barrage on the Ganga river at Farakka to divert significant portion of the dry season flow in order to make the Calcutta port navigable.

The growing problems in providing adequate drinking water to urban populations is a consequence of the lack of long-term planning and inefficient management of urban water usage.

Argues that excessive fluorides in groundwater are a serious water quality problem in some parts of Sri Lanka. The incidence of dental fluorosis shows a high correlation with the presence of groundwater in certain areas. Tube wells constructed in various rock types have shown different fluoride concentrations, possibly due to the different mineral constituents in these rocks and their relative capability of releasing fluoride ions into groundwater. It has been observed that the tube wells located in the dry zone have higher fluoride concentrations than those in the wet zone.