Author(s): So Kazama

Linked Author(s): So Kazama

Keywords: SWE; Snowmelt runoff; Energy balance model; Water storage;

Abstract: The hydrological model is composed of a SWE model based on water balance in snowpack involving a consolidation process and an assimilation method by observed data, a snowmelt model based on an energy balance model on the snow surface and below the snow bottom, and a runoff model based on kinematic wave theory on channels and storage function theory on hill slopes. Almost meteorological data for input to the simulation are available at 3 to 10 stations in the study basin but vapor pressure is only available at Akita city, out of the basin. The model is applied to the Yoneshiro River Basin from September, 2015 to May, 2016. The Nash Efficiency Coefficients are 0.70 for discharge at Futatsui point, the most downstream observing station, and 0.93 for snow depth at Kazuno point, the second highest station. Main errors for both data occur in the end of snowmelt season. Storages of snow and groundwater simulated in time series, show that the snow storage changes greatly larger than groundwater one, that snow storage variation has negative correlation to groundwater variation, and that the maximum groundwater storage arises in the beginning of the spring season. Also the simulation and a spectral analysis are carried out for daily variation correlation for both storages. The analysis indicates the strong negative correlation on more than 5 days period and time difference about 1 week for groundwater level changing after snowmelt.

DOI: https://doi.org/10.3850/38WC092019-0921

Year: 2019