entrenched stream

An entrenched stream or river is one on a flat plain that has cut a trench deep enough to contain its flow, even in flood conditions. A stream becomes entrenched when some change takes it out of equilibrium— a change in climate or land use, for example, or the uplift of land over which the river flows. Depending on the gradient of the stream and the make-up of the terrain it cuts through, the stream will be classified as heavily, moderately, or slightly entrenched. The sinuous meanders and terraced banks of the Colorado and Little Colorado Rivers in Arizona are the dramatic results of entrenchment, as is the expressive gooseneck formation of the San Juan River in Utah.

Michael Collier