Acceptance announcement of a paper by Dr. Hui Chen

We are pleased to announce that our paper, “Effects of Relief on Headwater Catchment (최상류 유역) Landscapes“, submitted to Geomorphology was accepted for publication on August 9.

Conceptual landscape representation of a headwater catchment, showing its division into hillslopes, unchanneled valleys, colluvial channels, and fluvial channels.

The accepted paper constitutes the first chapter of the doctoral thesis of Dr. Hui Chen, who is currently a postdoctoral researcher at the Guangzhou Institute of Geography, Guangdong Academy of Sciences, China. I sincerely appreciate his continued efforts in updating his thesis work to address the requests of anonymous reviewers, which has led to substantial improvements in the final version. The abstract of the article is below:

Headwater catchments, comprising hillslopes, valley heads, and colluvial valleys, are critical sources of water, sediments, and nutrients for downstream river networks. As mass movements dominate these landscapes, topographic relief has long been recognized as a primary factor controlling geomorphic processes and the spatial arrangement of geomorphic units in headwater catchments. However, how the transition from hillslope- to channel-dominated processes varies with relief remains debated. Particularly, the ways in which valley head location—defined as the uppermost tip of an unchanneled valley—and the lower boundaries of headwater catchments—defined by the downstream limit of colluvial dominance—scale with relief are not fully understood. To address these questions, we analyzed a drainage basin in South Korea that spans a wide range of relief. We delineated valley heads and headwater catchment extents, and quantified the likelihoods of hillslope materials reaching both valley heads and downstream river network. Our results reveal that valley heads shift downslope with increasing relief and that the lower boundaries of colluvial channels extend downstream, enlarging headwater catchments. Likewise, both likelihoods of sediment connectivity increase with relief. These findings demonstrate that both valley head position and headwater catchment extent are governed by relief through its effects on hillslope material supply, colluvial valley morphology, and debris flow transport. Notably, the observed positive correlation between valley head source area and relief challenges the stream power-based channel initiation model, which exhibits a negative slope-area relationship. This study advances understanding of geomorphic processes in headwater landscapes and provides insights for managing mountainous environments.

Acceptance announcement of paper by Ph.D. student Ha-eun

We are pleased to announce that our paper, “Classification of Colluvial Channels in a Mountain River: A Case Study of ‘Seoul National University Check Dam’ Catchment in Mt. Gwanak (산지 하천의 붕적하도 분류: 관악산 ‘서울대학교 사방댐’ 유역을 대상으로)”, subimitted to the Journal of the Korean Geomorphological Association (한국지형학회지) was accepted yesterday. Many thanks to Ha-eun for your hard work during your master’s thesis course, particularly for piloting the drone equipped with LiDAR sensor (link) and analyzing the collected LiDAR data. The article will appear in Vol. 32, No.2, scheduled for publication on June 30. The abstract of the article is below:

“The increasing frequency of extreme rainfall events due to climate change has heightened the risk of geomorphic hazards, such as debris flows and landslides, in mountainous areas. Colluvial channels, which typically occupy the uppermost sections of mountain river networks, serve as primary pathways for sediment transport during these events. Despite their geomorphic significance, few studies have classified colluvial channels, exhibiting diverse morphologies and processes over short distances, at the catchment scale. This study aims to classify colluvial channel subtypes in a granitic headwater catchment in Mt. Gwanak using a high-resolution(1 m) digital terrain model(DTM) generated from UAV-based LiDAR. For this purpose, 515 segments(10 m each) from colluvial channel network were extracted, and five geomorphic attributes were calculated from each segment: channel gradient, unit stream power, channel sinuosity, valley bottom width, and sediment connectivity. Hierarchical clustering based on the attributes revealed three subtypes: deposition-dominated, erosion-dominated, and highly coupled hillslope–channel reaches. ANOVA and PCA results indicated that channel gradient and valley bottom width were the most influential variables, with sediment connectivity also contributing to subtype differentiation. These findings highlight the morphological diversity of colluvial channels and offer a foundation for improving our understanding of sediment dynamics in mountainous areas.”