Bihar Flooded Despite Rainfall Deficit; Nepal Isn’t The Reason, Pg16

Key Highlights:

• Bihar experienced significant flooding affecting 2,157 villages across 14 districts and approximately 40.51 lakh people by September 9, despite a 27% rainfall deficit between June 1 and September 8.
• The flood pattern this year was unusual, with the Ganga river rising first, unlike previous years where Nepal-originating rivers like Bagmati, Kamla, Kosi, and Gandak typically swelled initially.
• Upstream rainfall in regions like Allahabad and Varanasi, along with discharge from neighboring states, significantly contributed to the Ganga's rise.
• Heavy, localized rainfall within Bihar during September, which was 31% above normal, exacerbated the flood situation.
• The Farakka Barrage is cited by state leaders as a major contributor to increased siltation in the Ganga, making the riverbed shallower and leading to more frequent overflows.
• The India-Bangladesh Farakka Treaty (1996) is approaching its expiration in December 2026, prompting demands for its review in Bihar.

Bihar Floods.jpg

Detailed Insights:

• The Ganga's early rise created a "backwater effect," impeding the drainage of its tributaries like the Gandak and Punpun into the main river.
• Bihar's extensive network of over 3,730 km of river embankments, while protective, does not eliminate the underlying flood vulnerability of its sediment-heavy alluvial landscape.
• Rivers in Bihar, including the Ganga, Gandak, and Kosi, carry enormous amounts of sediment, leading to the gradual rise of riverbeds relative to the surrounding land.
• The Farakka Barrage, commissioned in 1975, was primarily built to divert water to the Hooghly River to maintain navigability of Kolkata Port and flush out sediment.
• Critics argue that the barrage has trapped massive amounts of silt upstream, contributing to the shallowing of the Ganga riverbed in Bihar and increasing flood frequency.
• The India-Bangladesh Farakka Treaty (1996) governs the sharing of Ganga waters at Farakka during the dry season and is valid for 30 years.
• Bihar's high population density and the dynamic nature of its rivers, which constantly reshape their channels, further complicate flood management and necessitate frequent evacuations.

Key Concepts Involved:

• Backwater Effect: A phenomenon where the water level in a tributary rises due to an obstruction or high water level in the main river it flows into, hindering its drainage.
• Siltation: The process of sediment (silt, clay, sand) accumulating in riverbeds, reservoirs, or other water bodies, reducing their depth and water-carrying capacity.
• Farakka Barrage: A barrage on the Ganga River in West Bengal, India, designed to divert water into the Hooghly River to improve navigability of Kolkata Port.
• India-Bangladesh Farakka Treaty (1996): A bilateral agreement between India and Bangladesh for sharing the waters of the Ganga River at Farakka during the dry season.