Alluvial fan

Alluvial Fan. A low, outspread, relatively flat to gently sloping mass of loose rock material, shaped like an open fan or a segment of a cone, ...

alluvial fan -- n. A fan-shaped deposit of sand, mud, etc. formed by a stream where its velocity has slowed, such as at the mouth of a ravine or at the foot of a mountain.

alluvial fan Land counterpart of a delta . An assemblage of sediments marking place where a stream moves from a steep gradient to a flatter gradient and suddenly loses transporting power. Typical of arid and semiarid climates but not confined to them.

Alluvial Fan Large fan shaped terrestrial deposit of alluvial sediment on which a braided stream flows over. Form as stream load is deposited because of a reduction in the velocity of stream flow. Alluvial Terraces ...

AO An alluvial fan inundated by 100-year flooding (usually sheet flow on sloping terrain), for which average flood depths and velocities have been determined; flood depths range from 1 to 3 feet. D An area of undetermined but possible flood hazards.

A large alluvial fan, in blue, appears near the upper left; at its eastern (right) margin is a conspicuous area of red-rendered vegetation which marks a zone where subsurface and surface waters from snow melt in the Andes passes onto the high plains.

Alluvial Fan: A fan-shaped wedge of sediment that typically accumulates on land where a stream emerges from a steep canyon onto a flat area. In map view it has the shape of an open fan. Typically forms in arid or semiarid climates. Alluvium: ...

See also: Area, Surface, Plain, Region, Feature