Abstrakt
The study deals with catchments of the alpine lakes in the High Tatra Mountains (Slovakia). The lakes were subject of a long-term monitoring to detect chemical and biotic composition changes of lake water induced by acid atmospheric deposition and by its decline.
The studied processes required a quantitative approach to describe the characteristics of the catchments. The concept of catchment influence on lake water quality is in agreement with findings of ongoing research.
However, the definition and precision of lacking and estimated catchment parameters was not allowed without current technical and computing equipment because of the complexity of mountainous terrain. The key facility for studying relation between lake and its catchment was high resolution digital elevation model (2 x 2 m) of studied area.
The morphological parameters (slope, altitude, aspect, real surface area) for 26 catchments were obtained by analysis of the digital elevation model using tools of geographic information system. The land cover was detected by aerial images.
The catchment characteristics were correlated with water composition to response a different pace of recovering from acidification after the decline in acid deposition. One of the water quality indicators, sum of the base cations, proved its dependence to average slope of catchment that means the decrease in base cations leaching was pronounced in steeper catchments.
This pattern was observed only in southern hillside of the Tatra Mts range. The decline of the lake water nitrate concentration was more advanced in a rock or moraine-rock type of catchment and with a lowering proportion of meadow and dwarf pine in catchment.
These results are not in contradiction with previous studies in this lake area, suggesting the role of type vegetation proportion and indirectly pool of soil in catchment as drivers of run-off composition.