Estimation of groundwater recharge rate from river on an alluvial fan in the Nobi plain

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K06552
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Geotechnical engineering
• Research Institution: Gifu University
• Principal Investigator: KAMIYA Kohji 岐阜大学, 工学部, 教授 (50252119)
• Co-Investigator(Kenkyū-buntansha): 原田 守啓 岐阜大学, 流域圏科学研究センター, 准教授 (00647042) ; 児島 利治 岐阜大学, 流域圏科学研究センター, 准教授 (90346057)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 地下水涵養 / 扇状地 / 河川 / 地下水管理

Outline of Final Research Achievements

It is necessary for the sustainable use of groundwater resource to understand the water balance between groundwater recharge rate and pumping rate in order to avoid groundwater level lowering and ground subsidence. In this study, the groundwater recharge rate from river on an alluvial fan in the Nobi basin was evaluated based on the measurement of the river discharge changes on the fan. The groundwater recharge rate from Ibi river was about 14m^3/s, the recharge rate from Nagara river was 2.2m^3/s during the period of water shortage. Then flow path of groundwater recharged from the river was evaluated based on the resemblance of the ions data between the groundwater and the river water. It was revealed that the main groundwater flow path was located along the former river channel. Furthermore, it was suggested that the groundwater recharge was be able to estimate by a multiple linear regression equation using the observation data of the river water level and the groundwater level.

Free Research Field

地下水工学

Academic Significance and Societal Importance of the Research Achievements

本研究は，濃尾平野における貴重な水資源である地下水の持続利用に資するため，地下水の供給源としての扇状地河川の機能を究明して，木曽三川である長良川と揖斐川が重要な地下水涵養源であること，現状の揚水量に対して両河川が十分な地下水涵養量の関係にあることを明確にしたものであり，河川水と地下水を総合的に水資源管理することの重要性を示した．今後，地下水の保全と利用に関する管理手法の構築に寄与できると考えられる．