Rainfall in eastern river basins down 20% since 1951: Study, Pg9

Key Highlights:

• A new study reveals a 20% decline in precipitation in the catchment areas of India's eastern rivers—Ravi, Beas, and Sutlej—between 1951 and 2024.
• Precipitation in the western rivers—Indus, Jhelum, and Chenab—showed a statistically non-significant 6% reduction over the same period.
• The findings provide data-based evidence supporting India's argument for renegotiating the Indus Waters Treaty with Pakistan due to climate change impacts.
• The study, conducted by Vimal Mishra and Urmin Vegad of IIT-Gandhinagar, also noted significant groundwater depletion in the Sutlej and Ravi sub-basins.
• Major Indian dams like Pong, Bhakra, and Thein on eastern rivers experienced pronounced declines in annual water inflow, with Pong dam seeing a 34% reduction.

Detailed Insights:

• The Indus Waters Treaty allocates the waters of the eastern rivers (Ravi, Beas, Sutlej) to India and the western rivers (Indus, Jhelum, Chenab) primarily to Pakistan.
• India has previously put the treaty "in abeyance" following a terror attack and has served notices to Pakistan for a "review and modification" of the 1960 agreement.
• India's rationale for renegotiation includes population pressures, increased water demand, the need for clean energy development, and climate-induced changes in water availability.
• The study highlights that while most changes are due to natural variability, groundwater depletion is largely man-made, further altering the hydro-climatic conditions.
• Reservoirs in Pakistan, such as Mangla and Tarbela on the western rivers, have remained largely stable, unlike those on India's eastern rivers.
• The research suggests that the substantial hydro-climatic and geopolitical changes since 1960 question the long-term sustainability of the existing treaty framework.

Key Concepts Involved:

• Indus Waters Treaty: A water-distribution treaty between India and Pakistan, brokered by the World Bank, governing the sharing of the Indus River System waters.
• Catchment Area: The area of land where precipitation collects and drains into a common outlet, such as a river, lake, or reservoir.
• Groundwater Depletion: The long-term decline in the water table due to sustained groundwater pumping exceeding the rate of natural recharge.