Lowering water levels have indirectly led to deficiencies in soil organic content, and reduced agricultural productivity. Lastly, over-extraction of ground water has seriously affected water quality. Inadequate recharging of groundwater impairs the natural cleansing of arsenic which becomes water soluble when exposed to air, and threatens the health of 75 million people who are likely to use water contaminated with up to 2Mg/L of arsenic.
Climate change will exacerbate the problems caused by water extraction. The Himalayan glaciers are estimated to supply 30-40% of the water in the Ganges, which is particularly critical in the dry season prior to the monsoon rains.
The projected annual renewable water supply for 2025 indicates water scarcity. Although the Ganges catchment drains virtually all of the Nepal Himalayas and water supply per person in the basin ranges from adequate to ample, its dry season outflow (from December to February) to the sea is non-existent. Overall, excessive water diversions threaten to eliminate natural flows and severely damage people's livelihoods in the Ganges.