Author(s): Chanjoo Lee; Hun Choi; Donggu Kim
Linked Author(s): Donggu Kim, Chanjoo Lee, Hun Choi
Keywords: Biogeomorphology vegetation colonization channel morphology Naeseongcheon Stream
Abstract: A long-term monitoring project has been carried out since 2012 to analyze the changes in an active sandy river (Naeseongcheon Stream) in South Korea. In this study, some results of the monitoring project are given. During the period, rapid, extensive vegetation colonization and change in channel morphology were observed. These changes were linked to short-term hydrological fluctuations under the changing monsoon climate environment. The area of vegetation cover in Naeseongcheon Stream has been increasing, more rapidly since the period of rather weak hydrology (2014-2015), which provided a window of opportunity for vegetation establishment. During that time, pioneer herbaceous vegetation colonized densely channel area including bare bars and temporarily emerging riverbed. Although the colonized area and river banks was partially rejuvenated by several subsequent floods, the succession to woody vegetation continued resulting in a stable vegetation cover in areas that had been bare in the previous century. In this process, sediment carried by flood water was deposited on and around the vegetated area, while the low water channel incised causing vertical development of river topography causing bio-geomorphological change. In addition, the main channel width decreased in the relatively wide studied sites with secondary channels formed. The result of this study shows that the effect of rejuvenation by floods will decrease due to systematic changes in the river system. Based on the authors’ hypothesis, this change in Naeseongcheon Stream is systemic and was primed by human induced changes, which made the river system more susceptible to changes in rainfall and discharge, and in consequence to climate change. Furthermore, after initial vegetation settlement, changes in nutrients and temperature act as ‘positive feedback loop’, reinforcing vegetation establishment.
Year: 2025