The upper crustal-scale convection of fluids is one of the main factors distorting the conductive geothermal field. Geothermal anomalies caused by water circulation, as a rule, exceed the contributions from other factors (relief, sedimentation, structural and climatic effects). The measured temperature gradient has to be corrected before being used for calculation of the heat flow. In the present work, certain 2-D hydrothermal convection models have been analyzed using various permeability distributions and spatial configurations of fluid systems. Permeability anisotropy has also been included in some of the models, and variations of this parameter in the range 10(-10)-10(-16) m(2) have been considered. Numerical simulations reveal the possibility of considerable advective disturbances to the heal Bow. These disturbances depend on the physical parameters, and strongly on the geometry of fluid circulation. The magnitude of the hydrologic correction has been assessed for a variety of geological environments.