Estimation of the Water Budget Components of the Sfanta Ana Crater Lake in the Eastern Carpathians.

Environmental changes of the last decades are taking their toll on Lake Sfanta Ana, a crater lake situated in the Eastern Carpathians. The once crystal-clear water of the lake became greenish and turbid in the past decade due to flourishing algae populations, the surface area, depth and the volume of the water body marked a significant decrease during the past century. These changes are considered to be a consequence of sediment transport from the inner slopes of the crater, eutrophication attributed to nutrients of anthropogenic origin and decrease of water level. Having no permanent surface inflow and outflow sources, the water level of the lake depends on other water-budget components like precipitation, overland inflows during high intensity precipitations or snow-melting, evaporation, subsurface inflow and outflow. The research is aimed to identify the main components of the water budget, based on establishing relations between in situ measured meteorological data and the changes of water level. The results indicate a powerful relationship between water level, precipitation, and evaporation, the latter two are the main factors responsible for the variations of the lake's water level. [ABSTRACT FROM AUTHOR]