Author(s): Hyoseop Woo; Sangjoon Chung
Linked Author(s): Hyoseop Woo
Keywords: Riparian Vegetation; Water-level; Inundation; Temperature; Grain-Size
Abstract: This study identifies correlations among the physical and environment factors that might affect vegetation recruitment on sandbars in an unregulated stream. For this study, a downstream section of Naesung-cheon stream, one of the typical unregulated sand rivers in Korea, was selected and has been monitored for two years in order to collect relevant data. Data collected include rainfall in the section area; stream water-levels and temperatures and groundwater-levels and temperaturesat the stream section; and soil moisture of a riparian sandbar in the section. Results of the analyses show that the inundation frequency of a border zone between non-vegetated and vegetated areas on the sandbar was 44 days in the first year and 11 days in the second year, both of which occurred mostly in summer. Inundation frequency was considered to be one of the factors that affect the germination of vegetation. During the two years observed, no vegetation patches were detected. The lowest groundwater temperature, measured under the riparian sandbar, of 11℃ in early April and the highest one of 16℃ in early November were observed at the monitored riparian sandbar during the two years, which show a lag about three months behind the typical atmospheric water temperatures of the lowest in January and the highest in August in Korea. Meanwhile, observed stream water temperatures show a seasonal maximum difference of 30℃ and a daily maximum difference of 10℃. These results show that the groundwater temperature might affect vegetation recruitment and growth in the riparian area. Finally, the study shows that the grain size of riparian bed materials is also an important physical factor for the germination and growth of vegetation on sandbars because it affects a capillary action in ranges.
Year: 2013