Land use and superficial runoff in the lower catchment basin of the Uz river (period 1990-2012).

Abstract

The Uz River catchment is situated in the east of Romania; it is a component of the catchment basin of Trotus. In the lower sector of the Uz catchment basin, the risk of flash floods is accentuated by the physical and geographical conditions favouring the occurrence of extreme phenomena. The present research was conducted using specific indices, GIS techniques, etc, which enabled the delimitation of areas prone to floods. Land use, the physical-geographical and socioeconomic factors (lithology, slope, soil texture, profile curve, and land use) were integrated and processed in GIS. Land use was extracted from Corine Land Cover for the years 1990 and 2012. The changes in land use were highlighted through the application and spatial modelling of binary change index and of the Markov model. Each factor was ascribed bonitation grades by their degree of contribution to the rapid runoff from the slope. The values obtained for the flash flood potential index ranged between 1.56 and 4.71 during the period 1990-2012. The most important changes of the flash flood potential index value were found for the left slope of the Uz River valley, in the area of the localities of Salatruc and Darmanesti. Land use change, even at small scale, has increased hydrological risk phenomena because the minor riverbed was modified and a part of the floodplain forest was eliminated.

Keywords

• physical-geographical factors
• GIS
• Flash Flood Potential Index
• hydrological risk