抄録
In Japan, about 70% of the land area is mountainous and provides water resources to the remaining 30% of the area, where agricultural, industrial and urban activities are held. Projection of the impact of climate change on water resources at the local level would provide useful information to decision makers formulating policies for climate change adaptation. Therefore, the accurate estimation of low flow in the mountainous basin is very important for the water resources management now and in the future. This study focuses on the storage-discharge equation and its optimal parameters of the low flow. We prepared 7900 sets of the two parameters, the fractional recession constant Au and the storage exponent value N in the storage-discharge equation, to examine the sensitivity of these parameters in the process of the calculation of low flow. We carried out the hydrological analysis using the hourly hydrological model for two basins in Japan: the Sameura Dam basin located in the western Japan which has variability of rainfall, and the Shirakawa Dam basin located in a region of heavy snowfall in the eastern Japan. The result showed that the optimal sets of the Au and the N, which obtain lower relation error in the hydrological analysis, are expressed in the exponent function of the Au and the N.
