River corridors, even if highly modified or degraded, still provide important habitats for numerous biological species, and carry high aesthetic and economic values. One of the keys to urban stream restoration is reco...River corridors, even if highly modified or degraded, still provide important habitats for numerous biological species, and carry high aesthetic and economic values. One of the keys to urban stream restoration is recovery and maintenance of ecological flows sufficient to sustain aquatic ecosystems. In this study, the Hongje Stream in the Seoul metropolitan area of Korea was selected for evaluating a physically-based habitat with and without habitat structures. The potential value of the aquatic habitat was evaluated by a weighted usable area （WUA） using River2D, a two-dimensional hydraulic model. The habitat suitability for Zacco platypus in the Hongje Stream was simulated with and without habitat structures. The computed WUA values for the boulder, spur dike, and riffle increased by about 2%, 7%, and 131%, respectively, after their construction. Also, the three habitat structures, especially the riffle, can contribute to increasing hydraulic heterogeneity and enhancing habitat diversity.展开更多
A groyne zone formed by installing groynes functions as habitat or shelter for aquatic organisms during a flood. Since flow characteristics over a groyne zone are affected directly by groynes, understanding flow patte...A groyne zone formed by installing groynes functions as habitat or shelter for aquatic organisms during a flood. Since flow characteristics over a groyne zone are affected directly by groynes, understanding flow patterns due to shapes and types of groynes is of importance for designing groynes. In order to use groynes as an eco-friendly river structure, the ecological effects should also be considered at the design stage. In Korea, the ecological effects of groynes have rarely been examined or included for the actual design. In this study, a set of experiments were carried out to investigate flow pattern changes depending on different types of groynes. Based on the flow characteristics in the groyne zone, the scales of habitats and shelters by the groyne types were estimated. In addition, to test the applicability of a habitat evaluation model to the ecological design of groynes, River2D was used for a virtual river. For assessment of the groyne’s function of ecological habitat, the suitability index of a habitat for pale chub, one of the popular fishes in Korea, was used and the habitat areas by the groyne types were analyzed. The flow changes depending on the groyne types simulated by River2D show the applicability for the simulation of an ecological habitat to the groyne design.展开更多
This study sought to review whether large-scale experimentation can apply to actual rivers concerning the effect of topographical change by scour in the downstream area of natural-type low drop structures on the fish ...This study sought to review whether large-scale experimentation can apply to actual rivers concerning the effect of topographical change by scour in the downstream area of natural-type low drop structures on the fish habitat. The large-scale applicability experiment performed in this study installed low drop structures as the study object within the experiment channel and precisely surveyed topography in the downstream area of drop structures along with the hydraulic amount including water level and flow velocity under certain flow conditions. Based on topographical data acquired through the survey after the experiment ended, this study reviewed the change of suitability index and difference of weighted usable area by performing 2D habitat simulation. Ultimately, through the habitat simulation results in cases of considering and not considering scour in the downstream area of drop structures, this study analyzed the effects of topographical change in actual rivers on the habitat.展开更多
文摘River corridors, even if highly modified or degraded, still provide important habitats for numerous biological species, and carry high aesthetic and economic values. One of the keys to urban stream restoration is recovery and maintenance of ecological flows sufficient to sustain aquatic ecosystems. In this study, the Hongje Stream in the Seoul metropolitan area of Korea was selected for evaluating a physically-based habitat with and without habitat structures. The potential value of the aquatic habitat was evaluated by a weighted usable area （WUA） using River2D, a two-dimensional hydraulic model. The habitat suitability for Zacco platypus in the Hongje Stream was simulated with and without habitat structures. The computed WUA values for the boulder, spur dike, and riffle increased by about 2%, 7%, and 131%, respectively, after their construction. Also, the three habitat structures, especially the riffle, can contribute to increasing hydraulic heterogeneity and enhancing habitat diversity.
文摘A groyne zone formed by installing groynes functions as habitat or shelter for aquatic organisms during a flood. Since flow characteristics over a groyne zone are affected directly by groynes, understanding flow patterns due to shapes and types of groynes is of importance for designing groynes. In order to use groynes as an eco-friendly river structure, the ecological effects should also be considered at the design stage. In Korea, the ecological effects of groynes have rarely been examined or included for the actual design. In this study, a set of experiments were carried out to investigate flow pattern changes depending on different types of groynes. Based on the flow characteristics in the groyne zone, the scales of habitats and shelters by the groyne types were estimated. In addition, to test the applicability of a habitat evaluation model to the ecological design of groynes, River2D was used for a virtual river. For assessment of the groyne’s function of ecological habitat, the suitability index of a habitat for pale chub, one of the popular fishes in Korea, was used and the habitat areas by the groyne types were analyzed. The flow changes depending on the groyne types simulated by River2D show the applicability for the simulation of an ecological habitat to the groyne design.
文摘This study sought to review whether large-scale experimentation can apply to actual rivers concerning the effect of topographical change by scour in the downstream area of natural-type low drop structures on the fish habitat. The large-scale applicability experiment performed in this study installed low drop structures as the study object within the experiment channel and precisely surveyed topography in the downstream area of drop structures along with the hydraulic amount including water level and flow velocity under certain flow conditions. Based on topographical data acquired through the survey after the experiment ended, this study reviewed the change of suitability index and difference of weighted usable area by performing 2D habitat simulation. Ultimately, through the habitat simulation results in cases of considering and not considering scour in the downstream area of drop structures, this study analyzed the effects of topographical change in actual rivers on the habitat.
