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学術研究成果リスト

Detail of Grant Awarded Academic Researches

Project

Study on stream temperature variation in the Tama River and its causal factors

Academic
Research
No.305
Principal
Investigator
Tsuyoshi Kinouchi
Affiliation Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology
Research
Summary

This study revealed the characteristics of stream temperature variations in the Tama River and their causal factors by means of the analysis of existing datasets and field measurements. In the winter season, the stream temperatures at the Hino Bridge station and its downstream locations are distinctively high and show increasing trends for the period 1990 to 2010. In the summer season, the significant increase in the stream temperature was detected between the Ozaku intake weir and the Haijima Bridge station, where the flow rate reaches the minimum level. No obvious trend was found for the stream temperatures in the summer season. Stream temperatures are strongly affected by the dam release and water withdrawal in upstream locations, while more influences are imposed by tributary inflows and wastewater effluents in the downstream. The wastewater effluent is the major source of heat causing higher temperatures in the middle and downstream reaches in the winter season, whereas it works to maintain the normal flow and prevent extremely high temperatures in mainstreams in the summer season. The interaction between the stream and groundwater also attributes to the temperatures in the Tama River mainstream.

Collaborators

Xin Zhuohang (Doctoral course student)

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