SNOWMELT FLOOD FORECASTING IN THE YONESHIRO RIVER USING SNOWMELT MODEL AND PARTICLE FILTER

Abstract

 This study confirms the mechanism of snowmelt flood estimated from the high-altitude snow depth observation value in the Yoneshiro River basin, and proposes a new method of estimation for snow coverage distribution reflecting the altitude and basin topography in the slope direction. Furthermore, snowmeld flood is evaluated by a hydrological model with particle filters for the one-dimensional unsteady flow model and the snowmelt model improved by snow coverage distribution. Firstly, it is confirmed that temperature and rainfall more than 5 degree centigrade and 5 mm at Moriyoshiyama Ani Ski Resort can predict the high risk flood of the Yoneshiro River. Secondly, the model proposed can ensure the accuracy of the predicted water level 3 hours ahead at the downstream point. It becomes clear that it is important to consider the snowmelt model carrying out flood prediction in the middle and upper basin where the snow coverage is predominant and the influence of snowmelt is significant, and that it is possible to apply the model with only the particle filters except the snow melt model in the downstream regions.