Assessment of frequency and areal extent of overland flow generation in a forested mountain catchment

Abstract

Short time rainfall and throughfall measurements in the period May–October 2009, and the calculated saturated hydraulic conductivities of soils and isotopic hydrograph separations in August 2009 were used to estimate the frequency of the infiltration excess overland flow generation and the extent of saturated areas producing the saturation excess overland flow in the forested mountain catchment of the Jalovecký Creek, Western Tatra Mountains, northern Slovakia. The rainfall intensities exceeding 0.2 mm per 10 min occurred only in 2–4% of all data measured. Saturated hydraulic conductivities (K<sub>S</sub>) of soils were calculated by means of four methods based on the relationship between K<sub>S</sub> and soil texture. The comparison of K<sub>S</sub> with the measured rainfall intensities indicated that the infiltration excess overland flow could have been generated for 0–10% of the rainfall intensities measured. Isotopic hydrograph separation by means of the deuterium isotope indicated that the areas, where the saturated excess overland flow could have occurred, represented about 2–13% of the catchment during the analysed events. Despite the uncertainties connected with the assessments, the results are consistent with empirical knowledge of the catchment and limited older data.