The effects of topography resolution on upscaling point-scale processes and parameters on watershed hydrology numerical routing are investigated. Parsimonious continuous simulation was applied to two forested catchments with shallow and sloping soils, one medium-sized (123 km2) and one small-sized (4.5 km2), where saturation excess runoff prevails. The computed discharge showed highest sensitivity to spatial resolution, due to smoothing effects during aggregation of the digital elevation model caused by a coarse grid. The loss of information content of terrain curvature as consequence of the averaging procedure was related to the amplification factor required for the soil hydraulic conductivity to compensate the resulting retardation of the runoff hydrograph. A scaling relation has been developed that links soil hydraulic conductivity measured at the point-scale with that required at the typically much coarser modeling scale. The entropy concept for the measurement of information loss could be a good index for parameter rescaling of other basins where the terrain curvature is similarly scale-dependent.