Search

The doline density and their spatial distribution analysis is one of the methods used for karst relief morphostructural analysis. We present the results of morphometric features, doline spatial distribution and their relationship on Miljevci karst plateau based on digital elevation model (DEM). Altogether, 286 dolines were mapped in the study area. The doline density analysis has been applied. The results show that the doline spatial distribution is clustered. Two larger areas with densities of 30 and 34 dolines/km2 are determined. Their distribution along the river canyons could indicate the existence of a palaeodrainage network. The strongest link between the doline density and topography is with inclination and vertical relief dissection, whereas the number of dolines decreases with an increase of slope inclination and relative relief. Such distribution confirms the suitability of karstic plateaus without active drainage for doline formation.

Due to the high vulnerability of the karst aquifer to the surface contaminants, a precisely defined catchment area has the highest priority. In this study, the influence of slope inclination, the doline density analysis, and the water budget analysis in the delineation process of a complex karst catchment area is discussed. To define hydrogeological role of lithological units, cross sections of slope inclination and doline density were combined with hydrogeological cross sections, while the degree of karstification was used to describe the permeability of rock units. The verification of karst catchment delineation area was performed with water budget analysis. The methodology used for the determination of hydrogeological behavior and delineation of a complex karst catchment area (Slunjčica River basin, Croatia) is shown with the flow diagram. It has been found that the highest doline density appears in the range from 0 to 1° of the slope inclinations, and that it decreases with a higher slope degree. Although the results of this study confirm that even with the relatively small number of input data it is possible to define the karst catchment area, it must be emphasized that the doline density analysis presents an indispensable tool in the research related to the definition of karst catchment areas. [ABSTRACT FROM AUTHOR]

The doline density and their spatial distribution analysis is one of the methods used for karst relief morphostructural analysis. We present the results of morphometric features, doline spatial distribution and their relationship on Miljevci karst plateau based on digital elevation model (DEM). Altogether, 286 dolines were mapped in the study area. The doline density analysis has been applied. The results show that the doline spatial distribution is clustered. Two larger areas with densities of 30 and 34 dolines/km² are determined. Their distribution along the river canyons could indicate the existence of a palaeodrainage network. The strongest link between the doline density and topography is with inclination and vertical relief dissection, whereas the number of dolines decreases with an increase of slope inclination and relative relief. Such distribution confirms the suitability of karstic plateaus without active drainage for doline formation. [ABSTRACT FROM AUTHOR]

Dolines are considered to be among the most prominent karst formations, which is why they can serve as diagnostic forms of karst. Their spatial distribution and density are important indicators of an area’s degree of karstification, as well as of an overall geomorphological development. The aim of this paper is to determine the spatial distribution and the density of dolines, and also to analyse the influence of geological structure and morphometric features of the terrain (hypsometry, slope inclination, relative relief) on the spatial distribution of dolines in the area of southeastern Velebit. Moreover, for the first time with regards to the Croatian karst, the spatial distribution of dolines was compared with the spatial distribution of entrances into caves in the southeastern Velebit’s area of Crnopac. The data on the dolines’ position were adopted from 1:25,000 scaled topographic maps. All data were digitalised and analysed with ArcGIS 10.1 software in the GIS laboratory of the Geographic Department of the Faculty of Science in Zagreb. The research showed a strong influence of morphometric parameters of the relief on dolines’ density. The most prominent occurrence of dolines is linked with the areas ranging from 1000 to 1200 meters of altitude, slope inclination lower than 2° and the relative relief of 100 – 200 m per km2. Furthermore, the highest density of dolines was recorded in the Jurassic carbonate layers, while it was determined that the zones of main faults do not have a significant influence on the increase of dolines’ density. A high degree of correlation was determined by comparing spatial distributions and density of dolines and entrances into caves.

Dolines are considered to be among the most prominent karst formations, which is why they can serve as diagnostic forms of karst. Their spatial distribution and density are important indicators of an area's degree of karstification, as well as of an overall geomorphological development. The aim of this paper is to determine the spatial distribution and the density of dolines, and also to analyse the influence of geological structure and morphometric features of the terrain (hypsometry, slope inclination, relative relief) on the spatial distribution of dolines in the area of southeastern Velebit. Moreover, for the first time with regards to the Croatian karst, the spatial distribution of dolines was compared with the spatial distribution of entrances into caves in the southeastern Velebit's area of Crnopac. The data on the dolines' position were adopted from 1:25,000 scaled topographic maps. All data were digitalised and analysed with ArcGIS 10.1 software in the GIS laboratory of the Geographic Department of the Faculty of Science in Zagreb. The research showed a strong influence of morphometric parameters of the relief on dolines' density. The most prominent occurrence of dolines is linked with the areas ranging from 1000 to 1200 meters of altitude, slope inclination lower than 2° and the relative relief of 100 - 200 m per km². Furthermore, the highest density of dolines was recorded in the Jurassic carbonate layers, while it was determined that the zones of main faults do not have a significant influence on the increase of dolines' density. A high degree of correlation was determined by comparing spatial distributions and density of dolines and entrances into caves [ABSTRACT FROM AUTHOR]

This paper deals with the spatial density of dolines in the Croatian territory covered by karst. The purpose of this paper is to calculate the spatial density of dolines and show a correlation between calculated doline density values and certain geomorphological and geological factors of their origin and development. Therefore, it has been necessary to calculate the spatial density of dolines applying unique GIS methods of data collection and analysis to the entire study area. Doline density per unit area has been calculated based on the mapped doline bottom. 1:25,000 scale digital cartographic models have been used to determine the doline bottom. The given data have been used to calculate the spatial density of dolines applying a simple kernel method to an area of one square kilometre. The analysis of spatial differences in doline density has revealed that certain connections exist between doline development and relief morphometric parameters as well as lithological and structural terrain features. [ABSTRACT FROM AUTHOR]

Space and time variations of alluvial karst subsidence in the central Ebro Basin are analysed in trenches (paleodolines), aerial photographs (historical dolines) and field surveys (present-day active dolines). The measured subsidence rates, as well as a comparison between densities of paleodolines computed in randomly selected scan-lines and density of active dolines computed in maps, suggest that present-day subsidence in favourable areas is more intense than that of Pleistocene times. According to diachronic maps drawn from (a) different aerial photographs taken after 1946 and (b) field surveys on deformations in urbanized areas, subsidence behaved as a nearly steady process while the whole area was used for agriculture. In contrast, rapid changes (through periods of several tens of years) have occurred in urbanized areas, in which dolines expand their boundaries through small marginal collapses, shifting sharply their sinking centres to neighbouring sites. These rapid changes do not have an equivalent in observed paleodolines. [ABSTRACT FROM AUTHOR]