Risks Associated To Present Geomorphologic Processes In The Stemnic (Buda) River Basin

摘要

The paper analyses the main geomorphologic processes in the Stemnic (Buda) river basin, conditioned by the joint action of several factors, among which are the lithological peculiarities and the nature of superficial deposits, morphometric characteristics, climate, vegetation type and structure, properties of the soil cover etc. The Stemnic river basin with an area of 15662.52 ha is characterized by its elongated shape (the maximum length is of 30.5 km, maximum width of 8.5 km), its relative lithological homogeneity, but also by a variety of superficial deposits (eluvium, diluvium, colluvium and proluvium, alluvium) and by a relief energy of significant values between 136 m and 10 m (mean value of 73 m). Under these conditions, study area is characterized by a high degree of susceptibility to the occurrence of geomorphologic risk processes. For the morphometric and morphological analysis, we applied the method of the digital terrain model (DTM) with vectorisation of the contour lines on topographic maps with a scale of 1:5,000. In this paper we used indicators that highlight the particular frequency of landslides, especially in the upper and middle sectors, but the rather reduced frequency of deep erosion. Due to the satisfactory coverage of the ground with vegetation, the erosion reaction is differentiated, as it depends on the use of the land and the concentration of liquid flow on the slopes. Consequently, landslides of different ages, types and forms hold large surfaces in the basin (approx. 8%), while surface erosion affects most areas of the slopes, but with different intensities depending on their use and on agricultural technologies.