Author(s): Ana Maria Ferreira Da Silva
Linked Author(s): Ana Maria Ferreira da Silva
Keywords: Lluvial stream; Self-formation; Energy-analysis; Regime state; Channel geometry
Abstract: The process of self-formation of alluvial streams is considered in the light of the first and second laws of thermodynamics, and the Gibb’s equation. The stream is treated as an isolated and irreversible system. The related energy-analysis of a self-forming alluvium stream suggests that river self-formation is derived from the need of a stream to progressively decrease its average flow velocity to accommodate the increase in the entropy of the system with the passage of time. The regime development thus appears as the process in which the river alters its configuration (cross-sectional geometry, slope and effective roughness) so that the smallest possible value of average flow velocity (or, equivalently, of the Froude number) is reached. A method for the computation of regime flow width, depth and slope, based on the channel formation criterion resulting from this work, is presented. The regime channels computed from this method are compared with field and laboratory data from various sources.