The soil and groundwater flow of a hillslope adjacent to a stream has been studied using a physically based mathematical model. Values of soil parameters have been taken from investigations of Swedish till soils. Model simulations have been made in order to calculate groundwater outflow during and after a rainfall event, and to study the response to infiltration of soil and groundwater flow in different parts of the slope. The effects of soil layering and slope configuration have also been studied.
The simulated peak of groundwater outflow, occurring just after cessation of infiltration, is of the same order of magnitude as a typical streamflow peak in a small Swedish watershed. The increase of groundwater outflow during and after a rainfall event is, according to model simulation, caused by infiltration close to the stream. Hence, the soil properties of this part of the slope are of great importance to runoff generation.