ABSTRACT: Hydrograph analyses of grou nd water depletion process in the spring were used for estimation of karstification degree and g??oundwater sensitivity to pollution in the whole catchmenťs area.Differences in character of individual depletion hydrographs enable assessment of the anticipated extent of absorption, attenuation and self-purification processes during the groundwater penetration through the rock environment, between its infiltration and its outflow in the spring. The method was applied in the S part of the Slovensky Kras Mts., Dolny vrch / Alsohegy hydrogeological structure. In total, 66 individual recession curves from 9 gauged springs were analyzed. Depending on characteristic groundwater depletion hydrograph with independent sub-regimes, categories groundwater sensitivity to pollution were defined. Mean values of sensitivities to pollution were also linked to litostratigraphical units in the area.