Author(s): Yoshiyuki Yokoo; So Kazama; Masaki Sawamoto
Linked Author(s):
Keywords: Hydraulic conductivity; Base-flow behavior; Richards’equation; Numerical experiment
Abstract: A series of numerical simulations was carried out to investigate the relationship between “basin-averaged hydraulic conductivity” and long-term behavior of base-flow at hill-slope. Variable parameters were only hydraulic conductivities in the direction of the hill slope and the normal direction. Numerical experiments were divided into three groups. The first one varied hydraulic conductivity only in the direction of the hill-slope, and the second one varied it only in the normal direction to the hill-slope direction. The third one was performed to argue about the combined effects of the hydraulic conductivity in the both directions on the base-flow. According to the simulation results of the first group, peak runoff was proportional to hydraulic conductivity in the direction of the hill-slope, and the arrival time decrease exponentially as the hydraulic conductivity becomes greater. The results of second group showed that peak runoff increase logarithmically and the arrival time decrease exponentially, as the hydraulic conductivity increase in the normal direction of the hill-slope. The simulations of the third groups resulted that the gradients of the base-flow recession curves could be controlled by the magnitude of hydraulic conductivity in the direction of hill-slope.
Year: 2001