Estimation of runoff volume by geomorphometry and statistics analysis using digital elevation model in Tono area

Takeuchi, Ryuji  ; Kosaka, Hiroshi; Sato, Atsuya*; Tomiyama, Shingo*; Kageyama, Soichiro*; Ikeda, Makoto*

Subsurface water balance observation is a kind of methods in order to estimate a recharge rate. Results of the observation are affected by the various factors such as the scale, the topography, a geological feature, the climate. Therefore, the observation in the regional scale is necessary at many basins. The purpose of this study is to confirm the applicability of the method for the evaluation of runoff volume, which is one of parameters to evaluate the recharge rate by surface water balance observation, by geomorphometry and statistical analyses using digital elevation model (DEM). The runoff index which is the original indicator to evaluate the degree of flow rate on a catchment was calculated by the comparison between the result of geomorphometry and statistics analyses, and the observed data of river flow rate in the monitoring stations. Using this index, the flow rate of the Hiyoshi River was evaluated. The evaluated flow rate was about 60% against the observed flow rate.