Place · shifting river fan · India
Kosi river avulsion landscape
The great alluvial fan of the Kosi river in Bihar, Nepal and Bangladesh — one of the most dynamic river megafans in the world, with the Kosi migrating westward over 120 kilometres across the fan in the last 250 years through repeated avulsions. The 2008 Kosi flood, caused by the breaching of the Kusaha embankment in Nepal, inundated 1,000 square kilometres of Supaul-Madhepura districts in Bihar, affected 3.3 million people, and became the subject of the 2008 Kosi Crisis. The embankment politics — the 'Kosi project' of the 1950s-60s built India-Nepal joint embankments but reduced the river's natural meander space, raising long-term risks — remain central to the Bihar flood debate. The river is called 'the Sorrow of Bihar'.
- Date
- 1700–2026
- Function
- Landscape & environmental change
- Condition
- living mobile river
- River basin
- Kosi/Ganga
- Confidence
- Established / referenced
- Location
- 26.500, 86.900
Connections (2)
- AnalogueDamodar
The Kosi and the Damodar are the two Indian rivers most thoroughly re-engineered, and they were engineered in opposite directions. The Damodar was dammed upstream to hold floodwater back; the Kosi was embanked along its course to hold the channel in place. The dams silted and the embankments raised the bed above the plain, and both interventions made the next failure larger.
- River adjacencyBhadrāchalam
Bhadrachalam sits on the Godavari, the river the Ramayana's Dandakaranya chapters are set along, and the one whose sacred geography — Panchavati at Nashik, Nasik's Kalaram Temple, Rajahmundry, and Bhadrachalam's own ghat — makes the Godavari into a southern mirror of the Ganga. The temple's eastern-facing orientation looks across the river rather than toward the main shrine's compass axis, so the Godavari's course is the shrine's primary reference frame.
On these journeys
Sources
Fluvial geomorphology and flood-management literature on the Kosi megafan.
Open Kosi river avulsion landscape in the repository →