ABSTRACT: The Benesov-Usti groundwater system contains, especially in basal (A, AB) and middle (C, BC) aquifers, the biggest amount of thermal waters in Czechia with temperatures often over 30°C, in maximum nearly 40°C. Their exploitation is concentrated in the area of Usti nad Labem and Decin (Its original drainage area). Hydrological and thermic balance is necessary for future longterm exploitation and optimal protection of the whole widespread geologic structure of thermal water. The solution is drawn up through conceptual and numerical models of groundwater and heat flow in the frame of the whole hydrogeological structure unit.