Topographic conditions for spatial distribution of dolines in Valjevo–Mionica karst, western Serbia

Valjevo–Mionica karst is a limestone area within the easternmost flanks of the Internal Dinarides in western Serbia. In the spatial extent of 380 km2, it hosts typical karst landforms, primarily dolines, blind valleys, dry valleys and caves. Dolines are present on 75% of the total area, and the exact number of them within the area outline is 5319. The aim of the study is to determine the guidance factors for the spatial distribution of dolines, primarily morphological, while lithological, tectonic and climatic factors are presented at the basic level. Morphological factors in this study are analysed through morphometrical characteristics and calculations, which include the elevation, the mean topographical slope and the landform classification based on geomorphons. Digital elevation models with resolutions 90 m and 30 m are used. Data sources for doline positions were the topographical maps of 1:25,000 scale.Spatial distribution of dolines in the study area is rather uneven. Three zones (clusters) of higher concentration may be distinguished, where 34% of the total study area hosts 72% of dolines. These three zones are the karsts of the villages Lelić, Bačevci and Robaje, divided by deep canyon valleys. Maximum density of dolines, judging by the Kernel density method, is 33 dolines per km2 in the zone of the Stapar village, at the northwestern outskirt of the study area. The main factors influencing the spatial distribution of dolines are the topographical slope and the phases of morphological/hydrographical evolution of the area.