Hydrology plays an important role in the acidification of watersheds in Canada by airborne pollutants such as the wet and dry deposition of sulfate and nitrate. The pathways of the anions through the soil layers, the contact times with soil matrix, the snow accumulation and melting sequences and the groundwater flows are all important hydrological factors that influence the acidification processes. A hydrogeochemical model has been developed (TMWAM) and applied to Turkey Lakes Watershed. Results are presented on the calibration and confirmation of the model using the data from these watersheds. Particulate emphasis is placed on the hydrological factors and their relationships to the varying degrees of acidification observed at these locations. Preliminary results of linking the hydrological and hydrogeochemical models are discussed in the context of model applications as part of the national acidification assessment efforts in Canada.