トリニティ川におけるRFIDを用いた砂礫の追跡による土砂還元事業の評価

Abstract

The Trinity River Division of the Central Valley Project has executed since 1964 and habitat for aquatic animals have received an adverse impact from the construction of dams and transport water from the Trinity River into the Sacrament River as a part of the project. The Trinity River Restoration Program has conducted various projects to implement recovery of the Trinity River and its fish population. The objective of this paper is to estimate the mobility of the riverbed materials by tracing gravel with Passive Integrated Transponder tags (PIT-tags gravel) using Radio Frequency Identification system and to evaluate by computing the 2-dimensional (2D) model calculation for riverbed variation. From the results of the survey, we could detect the PIT-tags gravel at most 460 m downstream from the gravel injection point (IP) when floods have occurred twice after gravel injection and there is a possibility that the area of 200-250m downstream from IP seems to have a potential to catch gravel and to be a sandbar in the near future. And also we need to discuss the requirement for suitable sandbar for aquatic animal's habitat from the view point of the function of sandbar as a next work. Applying this concept would give better insights into preferable gravel augmentation method.