Geomorphology of Duero River Domain in Toro sector (Zamora province). Recent evolution of the Flood plain

Abstract

In the study area the Duero valley displays asymetric configuration (escarpment to the North and a smooth declivity to the South) and an extensive flood plain that has been intensely reworked. The great morphologic characteristic, the pattern from some rivers, specially the changes of direction of the Duero River in Castronuño and Toro, reflected the distribution of Paleogene and Neogene sediments, as well as the structural arrangement of the underlying substrate. Two morphogenetic stages can be distinguished: a first one which the Duero described a displacement towards the North and deposited an asymmetric system of terraces. In the second stage the flood plain is developed in which the are a different: two stretches: a) Castronuño-Toro stretch, with channel displacement towards the Southwest and channels and palaeochannels of variable sinuosity; and b) Toro-Peleagonzalo stretch, with channel displacement towards the North and straight patterns. In the second stage there are some evidences of channel migrations and frequent flooding on account of flow variability.