Regime channel development and time-growth of meander loops.

Ana Maria Ferreira da Silva, Laura Segura Serrano

Tuesday 30 june 2015

12:48 - 12:51h at Oceania (level 0)

Themes: (T) Sediment management and morphodynamics, (ST) River morphodynamics, Poster pitches

Parallel session: Poster pitches: 5B. Sediment - River

In this paper, the time-growth of meander loops is considered in the light of regime development. It is shown that this has the following implications: 1- the slope of a meandering stream must, at any stage of its development, be larger than the regime slope; 2- streams remain straight if the valley slope is smaller than the regime slope; and 3- not all meandering streams are destined to evolve to cut-off. The validity of these implications is largely confirmed in this paper on the basis of natural stream data of sand and gravel streams. For the present purposes, use is made of all straight and meandering river data available to the writers. The regime channel geometry, and consequently, the regime slope, is determined with the aid of the thermodynamic based regime method of Yalin and da Silva. The paper is used also as an opportunity to illustrate how substantial insight can be gained on meandering planimetric adjustments of equilibrium after changes in flow rate (induced by climatic changes or other reasons) by considering regime development principles.