Dynamics of Brâglez Riverbed (Someşan Plateau)
Gh. ROŞIAN, L. MUNTEAN, V. MĂCICĂŞAN, R. RUSU, v. ARGHIUŞ
ABSTRACT. – Dynamics of Brâglez Riverbed (Someşan Plateau). The main left tributaries of Someş along Surduc – Jibou sector (Brâglez, Almaş and Agrij), are characterized by the presence of obvious processes of lateral and vertical erosion at the level of the riverbeds. The field observations, as well as the position of these rivers and their catchment areas in the neighborhood of the lower Someş subsidence area, would easily be grounds for explaining the riverbed processes as caused by an unstable fluvial base level. More precisely, this base level would be moving downwards under the influence of subsidence movements of Tisa Plain or even because of the subsidence affecting Guruslău Basin. Starting from these more or less speculative deductions, this paper aims at checking and confirming the above-mentioned explanations or finding other causes for the dynamics of riverbed processes. In this sense, we analysed a correlation between the drainage in the catchment area and at the level of the riverbeds, on one hand, and the riverbed geomorphological processes, on the other hand. Brâglez River (in western Someşan Plateau) will be considered as a study case, as it provides an accelerated dynamics of riverbed processes. This situation will be compared with the one in the eastern part of the same plateau, where rivers like Borşa, Luna or Lujerdiu do not present obvious riverbed processes despite the similar climatic and geological conditions.
Keywords: drainage basin, base level, average runoff, erosion.