Peninsular river basins in India more likely to face widespread flooding than transboundary rivers: Study

Subject : Geography

Section: Indian geography

Context:

Past focus primarily on localized flooding, prompting researchers from IIT Gandhinagar to study and highlight widespread floods in major Indian river basins.

Analysis Findings:

Mahanadi and Narmada basins had the most frequent widespread floods (40 events), tied to seasonal trends influenced by monsoon patterns and heavy rainfall.
River basins in peninsular India (Narmada, Mahanadi, Godavari, Krishna, Cauvery) show higher probabilities of widespread flooding compared to Ganga and Brahmaputra.
- Narmada (59%), Mahanadi (50%), Godavari (42%), Krishna (38%), Cauvery (19%), Ganga (21%), and Brahmaputra (18%) indicate varying probabilities of widespread flooding.
Basins experience widespread floods during monsoon months, except Cauvery, with specific months linked to heavy rainfall periods (July-September for Godavari, Mahanadi, and Narmada).
Impact of Widespread Flooding: Widespread flooding, covering large basin areas, causes significant losses compared to localized flooding.
Climatic Factors: Rainfall patterns, monsoon intensity, and atmospheric circulations significantly influence flood occurrences.
Climate Change Impact: With a warming climate, the drivers of widespread floods are expected to change in timing, occurrence, and probability, signalling potential alterations in flood patterns. Atmospheric rivers play a significant role in these flood events.

Atmospheric River:

Atmospheric rivers are long, narrow bands of moisture in the atmosphere that extend from the tropics to higher latitudes. These rivers in the sky can transport 15 times the volume of the Mississippi River.
When that moisture reaches the coast and moves inland, it rises over the mountains, generating rain and snowfall. Many fire-weary westerners welcome these deluges, but atmospheric rivers can trigger other disasters, such as extreme flooding and debris flows.
- Also called “Pineapple Express” storms that carry moisture from Hawaii to the United States West Coast are just one of their many flavors.
The 2018 Kerala floods, 2022 Pakistan floods and lower Mississippi River floods in 2008, 2011 and 2015–19 have been linked with atmospheric rivers.