HYDROGEOLOGICAL INFLUENCE OF THE RAUTOVAC STREAM BASIN UPON THE QUALITY OF THE NIŠKA BANJA THERMAL WATERS

The thermal water sources in Niska Banja, Glavno vrelo and Suva banja,consist of three water components each, namelv, the thermal component, the coldpermanent component and the cold occasional torrent-karst component. The thermalcomponent genesis springs from atmospheric precipitation slowly infiltrated into theterrain through cracks and a porous ground. It is the regulator of the thermal springs'water temperature. An occasional karst-torrent water component is caused by a highdegree of karstification of the Koritnik and many days of atmospheric precipitation orsnow melting. This water components causes occasional cold refreshing just as itmakes the thermal springs muddy.The paper explores short-term and long-term changes of the temperatureregime of the thermal springs in Niska Banja as a function of the undertakenhydro construction repair works (1955-1956) as well as of the effect of forty years ofself-restoration of the herbal covering in the Koritnik river basin.The research results show two important changes, namely, first, a considerableimprovement of the phenomenon of an occasional drastic refreshing and of thethermal waters' getting muddy and, second, a permanent many-year increase of thewater temperature.