山地小流域に関する陸水学的研究(IV) 山腹部からの長期流出について

Abstract

The groundwater recharge was calculated from the groundwater level oliserved at the localunconfined aquifer at the head of a first-order valley in the Takigatani experimental basin from themountain slope to the aquifer, according to the method developed in the former paper. This resultwas used to construct the function of influence between the precipitation and the groundwater re-charge, averaged for the period of the observation of the groundwater level. A technique of theinverse transform of Duhamel integral was applied in it.The groundwater recharge was again calculated from the precipitation and the function ofinfluence and compared with that formerly calculated from the groundwater level, in order toexamine to what extent the runoff characteristics of the mountain sipoc was reflected by thefunction of influence.Although the function of influence represents the average aspect of the runoff from the mountainslope, it was found that the surface runoff component of the recharge was not correctly representedby the function of influence, and that the deviation between the two values of groundwater recharge(lescribed above showed a long term variation, because the percentage of the evapotranspiration lossvaried in long period, due to the change in the soil moisture conditions.