This paper reports on recent work on modeling the effect of spatial patterns in infiltration rate on the uncertainty in predicted runoff from two hypothetical catchments with distinct topographic characteristics. Specifically, in the first catchment the hillslopes are directly coupled to the channel, while in the second, the hillslopes are decoupled from the channel by floodplains. Spatial patterns of infiltration were generated as model inputs using the geostatistical method of stochastic simulation. Multiple infiltration scenarios were produced with spatial autocorrelation based on a spherical variogram model with a variable range and nugget and were used as inputs to the model COUP2D. Monte Carlo simulations were run for each condition. Results show that the uncertainty in modeled runoff due to spatially varying infiltration patterns varies with the magnitude of the runoff event through time and with different topography. Generally, increasing the range of spatial correlation of infiltration rates leads to increased connectivity in runoff pathways and an increased uncertainty in modeled runoff. Conversely, increasing the proportion of nonspatially correlated variation in infiltration decreased the uncertainty in modeled runoff to variable infiltration.