The Hindu Kush Himalayan (HKH) region, also known as the Himalayas, is the world’s third-largest fresh water reserve. The glaciers and snow here supply water to rivers that fulfill the water needs of millions. The upper reaches of the Ganges River, located in the Himalayas, are reliant on these glaciers and snow for their water.
Changing weather patterns and rising temperatures due to climate change are impacting the region's water systems. Researchers at the Indian Institute of Technology (IIT) Roorkee have conducted a study to understand the effects of climate change on the water flow and balance of the upper reaches of the Ganges River.
Source: aajtak
Study Objective
Dr. Praveen Kumar Singh of IIT Roorkee explained that this study was conducted to understand the impact of climate change on the upper reaches of the Ganges River. Specifically, it examined potential future changes in river flow, snowmelt, glacier water, and groundwater. A special model called SPHY (Spatial Processes in Hydrology), along with CMIP6 climate scenarios (SSP2-4.5 and SSP5-8.5), was employed for this study. These scenarios project future temperature and rainfall changes. The model was validated using flow data from the river at Devprayag.
Key Findings
Current Situation (1985-2014):
At Devprayag, rainwater constitutes 63.3% of the total river flow, snowmelt 14.9%, glacier melt 10.8%, and groundwater 10%. The average total flow during this period was 792 cubic meters per second, with contributions of 509.5, 117.5, 86.1, and 78.9 cubic meters per second from rain, snow, glaciers, and groundwater, respectively.
Source: aajtak
Future Projections (2076-2100)
Increase in Temperature and Rainfall: By the end of the 21st century, particularly under the SSP5-8.5 scenario, significant increases in temperature and rainfall are expected.
50% Increase in Total Flow: The model suggests a potential 50% increase in total river flow in the future, mainly driven by rainfall, followed by glacier melt and groundwater contributions.
57% Decrease in Snowmelt: By 2090, the water from snow is expected to decrease by 57%, as rising temperatures will accelerate snowmelt, reducing snow reserves.
No Water Shortage: Despite the decrease in snow contributions, the water supply will remain stable thanks to increased rainfall and glacier melt.
Impact of Climate Change
Effect on Snow and Glaciers:
Rising temperatures are causing the Himalayas' glaciers to melt rapidly, potentially reducing future water supplies from snow and glaciers.
Changes in River Flow:
With increased rainfall, river flow will rise, though it may become more seasonal, potentially leading to more frequent flood events.
Water Resource Management:
Changes in water availability will require better management for irrigation, drinking water, and other needs.
Importance of the Study
Researcher Rajeev Ranjan highlighted that the rivers of the Himalayan region, like the Ganges, are lifelines for millions, providing water for agriculture, drinking, and industries. However, climate change is altering these rivers' flow patterns. This study aids in understanding future water availability.
This understanding is crucial for governments and policymakers to plan for issues such as floods, droughts, and water shortages. Climate change will significantly impact the water flow in the upper reaches of the Ganges River. Although snow contributions will decrease, rain and glacier melt will maintain water supply. Nonetheless, proactive water management plans remain essential.
The study represents a critical step towards sustainable water resource management and addressing climate change. It will aid in forming policies not only for the Ganges Basin but across the entire Himalayan region to prevent future water scarcity and shield against natural disasters.
