Mitigating human impacts on stream temperature for conserving river environment and aquatic ecosystem

2014 Fiscal Year Final Research Report

• Project/Area Number: 23560606
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Hydraulic engineering
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: KINOUCHI Tsuyoshi 東京工業大学, 総合理工学研究科(研究院), 教授 (00355835)
• Project Period (FY): 2011-04-28 – 2015-03-31
• Keywords: 河川水温 / 多摩川 / 水・熱輸送解析 / 下水処理水 / 水面と河床の水・熱交換 / 都市化

Outline of Final Research Achievements

We studied the stream temperature of the Tama River, which has been strongly affected by the progress of urbanization. Through our monitoring and historical data analysis, we found an abrupt increase in the middle- and downstream reaches where a huge wastewater effluent is discharged, and the increase is even intensified in recent years. We also indicated that the interaction between groundwater and streamflow, and the summertime wastewater discharge contribute to suppress the daily maximum stream temperatures. Finally, we simulated stream temperatures assuming the introduction of two measures, i.e. the increase of flow rate by reducing upstream withdrawals and the larger interaction between groundwater and stream water by enhancing the rainwater infiltration and recharge to groundwater, to demonstrate the effect in mitigating the human impact on stream temperatures.

Free Research Field

水文学