Geology

Geomorphology

Climate/Hydrology

Sedimentology

Field Photos

References

Kosi fan as animation

An alluvial fan is defined as a body of sediment, whose surface form approximate to the segment of a cone which radiates down slope from a point on a mountain front, usually from a point at which a stream emerges (Summerfield, 1991). The most regular and well-defined of the cones takes its name from the Kosi river system in eastern Gangetic plains which is regarded as the largest wet alluvial fan in the world. Recent literature have favoured the use of the term “megafan” to avoid confusion with the smaller high gradient fans generally envisaged by sedimentary geologists.

Kosi river (IRS 1-C)