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Uvalas are a particular type of karst closed depression. While other types of closed depression – dolines and poljes – are regularly listed and relatively well defined in overviews of karst surface morphology, uvalas are either excluded or their vague identification is stressed. The leading idea of this paper is to obtain a clearer meaning of the term uvala and prevent its abandonment from karstology and general geomorphology. Within the study, 43 examples of uvalas have been selected. The studied uvalas are located in the Dinaric karst and karst of the Carpatho–Balkanides. All the case examples have been digitally processed in the same way. Creation of high-resolution digital elevation models enabled quantification of morphometric parameters, generation of inclination maps and cross-sections, as well as application of statistical analyses. Formation of the geographical information system of the studied uvalas was done using raster-based and vector-based GIS software packages. In 12 studied uvalas, detailed structural–geological mapping has been carried out, which revealed dominant development of uvalas along regional scale tectonically broken zones. A revised definition of the term uvala is suggested, leaving the opportunity for further discussion.
Digital elevation models (DEM) are digital representations of topography that are especially suitable for numerical terrain analysis in earth sciences and engineering. One of the main quantitative uses of DEM is the automatic delineation of flow networks and watersheds in hydrology and geomorphology. In these applications (using both lowresolution and precision DEM) depressions hinder the inference of pathways and a lot of work has been done in designing algorithms that remove them so as to generate depressionfree digital elevation models with no interruptions to flow. There are, however, geomorphological environments, such as karst terrains, in which depressions are singular elements, on scales ranging from centimetres to kilometres, which are of intrinsic interest. The detection of these depressions is of significant interest in geomorphologic mapping because the development of large depressions is normal in karst terrains: potholes, blind valleys, dolines, uvalas and poljes. The smallest depressions that can be detected depend on the spatial resolution (pixel size) of the DEM. For example, depressions from centimetres to a few metres, such as some types of karren, cannot be detected if the raster digital elevation model has a spatial resolution greater than, say, 5 m (i.e., square 5m pixel). In this work we describe a method for the automatic detection and delineation of terrain depressions. First, we apply a very efficient algorithm to remove pits from the DEM. The terrain depressions are then obtained by subtracting the depressionfree DEM from the original DEM. The final product is a digital map of depressions that facilitates the cal culation of morphometric features such as the geometry of the depressions, the mean depth of the depressions, the density of depressions across the study area and the relationship between depressions and other variables such as altitude. The method is illustrated by applying it to data from the Sierra de las Nieves karst massif in the province of Málaga in Southern Spain. This is a carbonate aquifer that is drained by three main springs and in which the depressions play an important role in the recharge of the aquifer. A doline density map, produced from a map of 324 detected dolines/uvalas, identifies three main recharge areas of the three springs. Other morphometric results related to the size and direction of the dolines are also presented. Finally the dolines can be incorporated into a geomorphology map.
One third of Turkey’s surface is underlain by carbonate rocks that have been subdivided into four karst regions. The carbonate rock units are about 200 km wide along the Taurus Mountains that attain elevations of 2500 m. Karst features of western Turkey bordering the Aegean and Mediterranean seas demonstrate the tectonic, lithological and climatic controls on the occurrence, movement, and chemical characteristics of groundwater. In Turkey all karstic feature, such as lapies, caves, sinkholes, uvalas, poljes, ground river valleys developed in all karstic areas. Karstification is related not only to the thickness and to purity of limestone, climate and height but also to tectonic movements. Water resources of karst terrains of Turkey are relatively rich and as such are very important for the economic development of the country. High mountain chains, very often associated with the karst terrains, are responsible for some important and beneficial characteristics of these water resources. Four karst regions are: (1) Taurus karst region, (2) southeast Anatolia karst region, (3) central Anatolia karst region, and (4) northwest Anatolia and Thrace karst regions.
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