Rainfall threshold for hillslope outflow: an emergent property of flow pathway connectivity
Résumé
As a test case, we applied percolation theory to the well characterized experimental hillslope at the Panola Mountain Research Watershed. Analyzing the measured rainstorm events and the subsurface stormflow with percolation theory, we could determine the effect of bedrock permeability, spatial distribution of soil properties and initial water content within the hillslope. Our results indicate that the measured variation in the relationship between rainstorm amount and subsurface flow is dominated by the initial moisture deficit, the loss of free water to the bedrock, the limited size of the system and by the connectivity due to macropores. The values of the model parameters were in agreement with measured values of soil depth distribution and water saturation.