alluvial

Referring to fluvial contexts, processes and products, so that an alluvial channel is a river channel cut in alluvium; it is self-forming, in that its form reflects the load and discharge of the river rather than the constraints of a bedrock.

An alluvial fan is a fan-shaped landform composed of alluvium dropped by a river after it loses momentum as it enters a broad valley from a narrow, upland course. The fan shape is the result of the river swinging back and forth over the aggradation deposits while the apex is fixed at the point where the river emerges from the uplands. It is the terrestrial equivalent of a delta.

An alluvial cone is similar in origin, but tends to have a steeper slope. Cones tend to grow from seasonal streams in semi-arid or arid areas, such as the western flank of the Sangre de Cristo range, Colorado. Alluvial fill would appear to be another term for alluvium, and the process of sedimentation from fluvial channels may also be described as alluvial filling. This generally comes about in one of four ways:

▪ when the discharge decreases;
▪ when the amount of load increases;
▪ when the width/depth ratio of the channel changes;
▪ when a change in base level lowers the gradient.

The adjective has one meaning:

Meaning #1: of or relating to alluvium
  Pertains to noun: alluvium (meaning #1)