Floods

Rationale: The Kosi River is famous for aggrading its bed with massive sediment loads brought down from the Himalayas, causing it to frequently shift its course westward across its fan, resulting in severe floods in Bihar.

Rationale: The Rashtriya Barh Ayog (National Flood Commission), set up in 1976, submitted its comprehensive report in 1980, making landmark recommendations on flood forecasting, zoning, and structural measures.

Rationale: Braiding occurs when a stream has a high sediment load coupled with rapid and wide fluctuations in discharge, causing the river to deposit sediment within its channel and split into multiple shifting threads.

Rationale: Floodplain zoning regulates human activities in high-risk zones without altering the physical flow of the river, making it a classic non-structural mitigation strategy.

Rationale: In Indian meteorological terminology, a cloudburst is a localized precipitation event where rainfall intensity equals or exceeds 100 mm (10 cm) per hour over a small geographical area.

Rationale: Uttar Pradesh has the largest absolute geographical area prone to floods in India due to its extensive river network, including the Ganga, Yamuna, Ghaghra, and Rapti systems.

Rationale: Established in 1948, the Damodar Valley Corporation was India's first multipurpose river valley project, explicitly modeled after the Tennessee Valley Authority (TVA) of the United States to tame the 'Sorrow of Bengal'.

Rationale: Embankments confine rivers to narrow channels, preventing silt from spilling onto natural floodplains. This trapped silt deposits on the river bed, raising the bed level above the surrounding land and increasing long-term flood danger.

Rationale: The Central Water Commission (CWC) operates an extensive network of flood forecasting stations across major river basins in India in collaboration with the IMD.

Rationale: Unplanned urbanization often involves building over natural water bodies, streams, and wetlands, drastically reducing the natural retention and drainage capacity of urban catchments.

Rationale: Coastal Tamil Nadu and southern Andhra Pradesh receive heavy rainfall during the northeast monsoon (retreating monsoon), frequently leading to severe floods and inundation.

Rationale: Lag time represents the delay between the occurrence of peak precipitation and peak river discharge, critical for issuing advance flood warnings.

Rationale: The Mahanadi delta in Odisha is prone to deltaic floods where heavy monsoon discharges fail to find adequate outlet through the distributaries, spilling over the deltaic plains.

Rationale: A 100-year flood is a statistical designation meaning there is a 1 in 100 (1%) chance of a flood of that specific scale occurring in any single year.

Rationale: The horseshoe-shaped configuration of the eastern Himalayas and Purvanchal hills forces moisture-laden summer monsoon winds to rise rapidly, causing massive orographic rainfall in the Brahmaputra basin.

Rationale: Mangrove forests create a dense network of roots and stems that absorb wave energy, reduce storm surge heights, and protect coastal lowlands from inundation.

Rationale: Established under the Disaster Management Act of 2005, the NDMA is the apex body responsible for framing policies and guiding disaster mitigation across India.

Rationale: Arid rivers like the Luni normally remain dry but can experience sudden, violent flash floods triggered by intense, short-duration convective storms in their upland catchments.