Determination of the ecohydrographical regions in Slovenia
- Authors: Mitja BRILLY, Lidija GLOBEVNIK, Andrej VIDMAR
- Citation: Acta hydrotechnica, vol. 21, no. 34, pp. 23-36, 2003.
- Abstract: The European Union Water Framework Directive (WFD) provides the framework for protection and improvement of the aquatic environment. Surface water bodies should be classified into categories and differentiated according to type. A method for the differentiation of rivers and lakes in Slovenia into different types of ecohydrographical regions is presented in the paper. The WFD provides a two-fold characterisation of surface body types: System A according to Illies with ecoregions presented in Annex XI of WFD, and System B, which gives the grounds for consideration of specific country conditions according to obligatory and optional factors. The same degree of differentiation should be achieved by System B as by System A. The contours on the map, provided by WFD for System A, are rather vague and do not coincide with the contours of watersheds. They divide the territory of Slovenia into two and four ecoregions, respectively. System B implements ecohydrographical regions, which are regions with homogenized obligatory factors. Obligatory descriptors define large rivers with watersheds larger than 1000 km2, and lakes. Small- sized rivers are differentiated according to ecohydrographical regions. Types of rivers (both large and small) are then determined by the optional descriptors: transport of sediment and substratum composition. The country is subdivided into seven ecohydrographical regions: three in the Adriatic Sea basin and four in the Danube River basin. Watershed borders determine the boundaries of ecohydrographical regions. The main factors for determination of ecohydrographical regions are altitude for alpine regions and geology for regions with predominantly karst phenomena.
- Keywords: Water Framework Directive, surface water body types, ecoregions
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