Several practical models of the subsurface hydrologic system are constructed. These models have as their core the two-dimensional groundwater flow equation with a vertical recharge term and subject to the assumption of horizontal flow. The recharge term is used to represent the hydrologic processes on the surface and in the unsaturated zone as far as their input to the groundwater system is concerned. In this sense, the models can be used to simulate the subsurface hydrology of a watershed--not simply the groundwater system. Various methods are discussed for evaluating the recharge term including a simple water mass balance, a climatological water balance, a more complex water balance and a recharge distribution based on the USDAHL-70 model of watershed hydrology. Application of several of the models to a watershed in Colombia, South America indicates that the models are relatively easy to apply . (Modified author abstract)