Balance of Dynamic River Forces

Lane's stability concept equates the product of a river's sediment load and sediment size with the product of the same river's slope and discharge. This figure provides a colorful and illustrative interpretation of Lane's stable channel balance, according to fluvial geomorphologist D. Rosgen.

When sediment load or size are disrupted, the balance with Stream slope and discharge is offset, and the imbalance may result in Aggradation or Degradation problems. FGM analysis is must look critically not only at slopes and discharge, but also at the much harder to measure sediment dynamics, to anticipate channel alterations and predict channel evolution.

Image Courtesy of Rosgen