Estimation of Surface Runoff and Groundwater Infiltration Components by the Groundwater Recharge Model (Itoshima Area, Japan)

This paper presents the estimation of the parameters F_∞, and (r)_1/2 used in the groundwater recharge model by separating the surface runoff component for isolated rainfall event. The time-area distribution method was used. Several types of land use were considered. The watershed of the upstream of Sakurai River at Suematsu Bridge in Itoshima Peninsula which includes the western part of the new campus (Ito campus) area of Kyushu University in southern Japan, was selected as a site study to test the model approach. Since more than 80% of study area is covered with forest, the proposed model considers rainfall interception by forest canopy. The runoff parameters F_∞, and (r)_1/2 were identified in this study using records of river discharge at the outlet point of the watershed. The results indicate that the separation approach satisfactorily predicted runoff parameters for different land use, and also showed that simulated runoff results agree well with observed results