CHARACTERISTICS OF WATER RESOURCES DUE TO SNOW IN THE TOYOHIRA RIVER CATCHMENT AREA

Abstract

 To investigate the characteristics and trends of water resources in the snow-covered regions of the Hoheikyo and Jozankei dams, we conducted an analysis using the inflow data of the hydrology and water quality database and the snow observation data at the upstream point of the Jozankei dam. Defining the snowmelt period from April 1 to June 30, we found that the total inflow volume into the dam lakes during the snowmelt period of the Hohei-kyo and Jozankei dams from 2003 to 2022 was generally synchronized, and that the total inflow volume during the snowmelt period for both dams decreased annually. The maximum snow water equivalent and snow depth at the Jozankei observation site occurred earlier, indicating an earlier melting period. Furthermore, based on the observations using the snow water equivalent, we investigated the relationship between the snowfall and snowmelt during the snow accumulation period in the Jozankei dam basin and the inflow volume during the snowmelt period into the dam lakes.