September 19, 2020 2:36:17 am
A study commissioned by the Observer Research Foundation, published this month, has found that the retreat of glaciers in the Himalayan Hindu Kush region is now affecting the surface water and groundwater availability in the region, and has adversely affected springs – a lifeline for the population in hill areas.
The study, carried out by Dr Anjal Prakash, IPCC author and Research Director of Bharti Institute of Public Policy at the Indian School of Business in Hyderabad, says that unless a coherent nationwide policy is developed for springs and Himalayan groundwater, villages and towns in the region will face a severe water crisis in coming decades.
Studies by ISRO show that approximately 75 per cent of the Himalayan glaciers are retreating at an alarming rate.
“These retreats will increase the variability of water flows to downstream areas and endanger the sustainability of water use in the earth’s most crowded basins. Receding glaciers would also have an impact on the rates of groundwater recharge in some areas,” says the study. The decline in groundwater due to anticipated decline of glacial meltwater is likely to affect the Ganges basin the most, it says.
“Glacial decline is closely related to climate change. The study looks at the interconnectivity between this and the groundwater and surface water in the area. There are 5 million springs in the Himalayas and they are showing a decline because of overuse by an increasing population, but also because of retreating glaciers and depleting ground water levels. This is alarming because the populations that live in the upper and middle Himalayas, in villages and even towns, are dependent on spring water. NITI Aayog has set up a committee to look at springs in the Himalayas. But there needs to be a mission mode policy on this,” said Dr Prakash.
“In many parts of HKH springs are drying up due to prolonged pre-monsoon drought as a result of climate change, threatening the way of life for local communities and downstream areas,” said Dr Vishal Singh, Executive Director of Centre for Ecology Development and Research.
The HKH region extends across 3,500 km over eight countries—Afghanistan, Bhutan, Bangladesh, China, India, Myanmar, Nepal and Pakistan. It has the biggest reserves of water in the form of ice and snow outside the polar regions, and is the source of 10 of the largest rivers in Asia. About 1.3 billion people directly depend on the HKH ecosystems, including for irrigation, power and drinking water.
For the upper Indus basin, glacier melt may contribute up to 41 per cent of the total runoff, 13 per cent in the upper Ganga basin and 16 per cent in upper Brahmaputra. While initially the retreating glaciers will not have a direct impact on water flow in rivers, except in the Indus where 26 per cent flow is from glacier melt, this is likely to change soon, says the study.
Climate warming is affecting hydrological regimes in the HKH region because of factors like changes in seasonal extremes, increased evapotranspiration, and changes in glacier volume.
However, the study forecasts that in all three basins, there would be a decrease in snow and a rise in glacier melt by the middle of the century. Initially, there will be an increased amount of meltwater available, but this quantity will decline abruptly as the glacier storage is reduced.
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