Distribution characteristics of hydraulic properties on a mountainous hillslope

Abstract

Understanding the heterogeneity of infiltration has been a challenging issue in improving knowledge of hillslope hydrology. Spatial distributions of the hydraulic properties on a hillslope were measured using tension infiltrometers over four different time periods. The hillslope examined has a permanent channel initiation point located in the Bongsunsa watershed, which is a headwater for the Han River basin, South Korea. Surface hydraulic conductivity is affected by both pore development structure and soil texture. In order to explore the impact of the relationship between spatial topographical features and the surface hydraulic properties, several terrain analyses and flow evaluations were performed. The importance of flow through a larger pore size was confirmed in both the scale and variation of the spatial and seasonal perspectives, respectively. Although there is a substantial heterogeneity of field measurements in both spatial and temporal contexts, the threshold for characterizing the spatial variation of hydraulic properties can be obtained through several statistical tests, using two distinct data subsets delineated from an analysis of the terrain attributes and hydraulic properties. Results reveal that threshold behavior appears to be restricted for hydraulic properties associated with the generation of the flow through macropores.