Process-Based Topographic Analysis and Hydrological Properties in Temperate Mountainous Catchments

Abstract

How much is known about the relationship between topography and sediment dynamic in mountainous catchments? A previous numerical process-based study, with a high-resolution digital terrain model (DTM), reported a quantitative relationship between annual precipitation and river incision. However, the ability to predict sediment transport within mountainous streams is still needed in order to integrate sediment management in rivers. In this study, we focus on the relationship between topography and hydrologic properties in temperate mountainous catchments as a fundamental study to connect topography and sediment movement. The studied mountain catchments located in northern Kyushu, Japan, are composed mainly of Mesozoic granitic rocks. In the catchments, three terrain parameters were determined with topographic analysis using a process-based model and airborne LiDAR survey data. Hydrological measurements such as electric conductivity and water discharges were also carried out on the streams. One of the studied terrain parameters, D/K, shows a bimodal distribution indicating a few groups in our study area. The values also show a relationship with water discharges. These results show that the basin topography would have been formed through similar surface processes and correlate with the current hydrological environment. This process-based modeling could be an effective tool to quantitatively analyze short-term impacts of climate on topography.