A two-dimensional ground heat loss model is used to investigate the effect of bottom reflectivity on ground heat losses for solar ponds. In the model, convection boundary conditions are used between water and ground. The convection heat transfer coefficient is estimated using the correlations given for heated or cooled flat plates. The local rate of absorption of the solar radiation in the pond is determined for the direct and diffuse components by the exact treatment of the radiation problem. The fractions of heat adsorbed by the pond bottom that is transferred to soil and to water are investigated for different bottom reflectivities.