Utilización de las características geomorfológicas de los cauces fluviales como método de estudio de la dinámica de cuencas montañosas que no disponen de registros liminimétricos

Abstract

In order to study the flood and sediment pattern of the high Llobregat basin (a mountainous catchment of about 500 Km2 with only two staff gauges) we have used a method which consistes of an inventory of the geomorphic and geometric characteristics of the stream channels. 358 points in the drainage net have been selected to report observations on the sediment grain size, lithology, mobility; on some other geomorphic aspects like bed stability, presence of gullies or mass-movements, etc.; and we have also measured the hydraulic parameters of the minor bed and the trash fines laid by the last ¡lood. Such data have been analysed lo obtain a stream channel classification of the stability and sedíment transportatíon (8 standards), a qualitative classífication of the basins, and an ordinal or semiquantitatíve classifícatíon of the degree of activity of each basín. The [atter has been subordinated fa the qualitative one because we have evidenced a dependence between them. The method partly described in the paper is a relatively cheap tool useful to obfain a general pattern of the basin, and especially fa aid the choice of sorne representative catchments to be instrumented.