Author(s): Yoshihisa Akamatsu; Takanori Kono; Ryutei Inui
Linked Author(s):
Keywords: Ecological model; Riverbed excavation; Takatsu River; Impact assessment
Abstract: In recent years, a riverbed excavation project is planned and implemented for safety against frequent floods in many rivers of Japan. It is necessary to predict the impacts on the growth and habitat of aquatic organisms because riverbed would be largely altered by the excavation. In this study, we developed an ecosystem model, which can do the effects assessment of a project. Then, we examined the effects of the riverbed excavation project on the riverine ecosystem in the Takatsu River with the model. As a result, the ecosystem model has sufficient reproducibility for physical environmental variables and the biomass of aquatic organisms. Moreover, the ecosystem model estimated that the distribution of water depth and velocity changed due to the riverbed excavation and the longitudinal distribution of water temperature also changed. In addition, the biomass distribution of aquatic organisms changed in response to the differences in the physical environment. When total biomass in the calculated interval was examined, the attached algae and benthic invertebrates were maximally up 12.7% and 26.3%, respectively. In contrast, the biomass of fishes did not significantly change (~2% increase/decrease) in the total biomass.
Year: 2020