Profile of Equilibrium

profile of equilibrium [¦prō‚fīl əv ‚ē·kwə′lib·rē·əm]

(geology)

The slope of the floor of a sea, ocean, or lake, taken in a vertical plane, when deposition of sediment is balanced by erosion.

The longitudinal profile of a graded stream. Also known as equilibrium profile; graded profile.

---

Profile of Equilibrium 

the longitudinal profile of a riverbed that is cut by a river under the conditions of a stable level of erosion, negligible local tectonic movement, and a constant climate. The gradients along the river are then distributed in such a way that the specific capacity of the stream changes little from the source to the mouth. The shape of the river’s profile of equilibrium depends on changes in such factors as water discharge, detrital deposits, rock characteristics, and riverbed shape. These changes affect erosion and accumulation processes. However, the determining factor in shaping the profile of equilibrium is the nature of the relief along the river valley; there is a rapid drop in riverbed gradients when a river emerges from a mountainous area onto a plain. The concept of the profile of equilibrium is a hypothetical one and is chiefly of theoretical importance in determining the extreme profile toward which a river strives.