Transient effects of surface temperature and groundwater flow on subsurface temperature in Kumamoto Plain, Japan

Abstract

Groundwater flow systems evaluated from observed hydraulic potentials agree well with the regional and local groundwater flow system estimated from subsurface temperature in Kumamoto Plain. Subsurface temperature could be a good trace to detect the groundwater flow systems. Repeated measurements of groundwater temperature shows that the subsurface temperature increased during the last 15 years due to surface warming in the groundwater recharge area, and decreased in the discharge area because of decreasing in groundwater flow and recharge rates. These results are also supported by the analytical solutions of subsurface temperature to the heat conduction–advection equation under the condition of surface warming.