Temporal variability of subsurface stormflow formation

摘要

Subsurface stormflow (SSF) can play a key role for the runoff generation athillslopes. Quantifications of SSF suffer from the limited ability topredict how SSF is formed at a particular hillslope and how it varies intime and space. This study concentrates on the temporal variability of SSFformation. Controlled sprinkling experiments at three experimental slopeswere replicated with varying precipitation intensity and varying antecedentprecipitation. SSF characteristics were observed with hydrometricmeasurements and tracer experiments. SSF response was affected in differentways and to varying degree by changes of precipitation intensity andantecedent precipitation. The study showed that the influence of antecedentprecipitation on SSF response depends on how SSF is formed at a particularhillslope. As formation of SSF was hardly influenced by the increase ofprecipitation intensity subsurface flow rates were not increased by higherintensity. However, timing and relevance of subsurface flow response changedsubstantially at different precipitation intensities, because saturation andflow formation occurred above the soil-bedrock interface, but also withinthe topsoil depending on precipitation intensity.