Abstract
The notable features of the Kumamoto area located at the foot of the western slope of Mt.Aso(a volcano)is formed by groundwater flow based on the basin characteristics peculiar to Quarternary volcanic rocks.In utilizing and managing groundwater in such an area, the results of a hydrological analysis will be unreliable if groundwater balance with the exception of recharge from surface water and precipitation is not considered in relation to that of the hydrological cycle system as a whole.The authors have elucidated a change in the water cycle in light of the groundwater flow by means of a macroscopical water balance of each river basin in the above area.The approach adopted in this research is beneficial in the water management of the basin.
