HYDROLOGIC MEASUREMENT USING SNOWCOVER WEIGHTMETER IN WINTER

Snowmelt runoff is a precious water resource in cold region. However it causes disasters by influence of a warm air and a rainfall in spring. Therefore accurate estimation of snow water equivalent and forecast of snowmelt discharge are vital for river management. We investigated how snow water equivalent changes with time in the Jozankei Dam basin and on the premises of the Ishikari Experiment Laboratory. It was done by continuously monitoring of snowcover weight and snowmelt discharge using snowcover weightmeters and lysimeters. We observed time-lag of snowmelt runoff and excessive snowmelt runoff. It was caused by structure of snowcover layer. We proposed a simple equation for estimation of snow density by multiple linear regression analysis. We estimated snow water equivalent in the Jozankei dam basin by using the equation. The result of estimation is almost satisfactory.