Development of a Snowmelt-Runoff Model Considering Dam Function for the Ane River Dam Basin, Japan (PAP014812)
Pedro Luiz Borges Chaffe, APIP, Yosuke Yamashiki, Kaoru Takara
Floods in a changing climate
The Ane River Basin is located in Japan and snowmelt during spring is a major contributionto total river discharge. The proper estimation of the snowmelt runoff in the maritime snow area isnecessary for the understanding of the hydrological processes of the region and for analyzing differentclimate change impacts in the water resources of the area. The objective of this paper was to developand test an energy balance snowmelt and runoff model for the Ane River Dam catchment consideringdam reservoir. The Ane River Dam (ARD) has a catchment area of 28 km2 mainly covered by forest. Themodel developed was a combination of three different models: an energy-balance Soil-Vegetation-Atmosphere-Transfer model for the snowmelt calculation; a cell distributed runoff model (CDRMV3); andthe implementation of a dam reservoir routing routine using the Level Pool method. In the model we setthe grid cell where the dam is located to have the reservoir rules. The runoff model was calibrated byusing dam inflow hydrographs for three summer events. Snow accumulation and depletion patternrepresented well the observed snow depth at the crest of the ARD. The total snow depth wasoverestimated due to the constant snow density which was used in the model. The time of snowdisappearance was well estimated for the winter of 2010-2011, however, it was 10 days late in the winterof 2010. The simulated peak outflow from the dam was overestimated but the recession curves wereaccurate. The use of the summer calibrated parameters for the three winter events demonstrates thedeveloped snowmelt-runoff model sensitivity to snowmelt and rainfall. However, there are still verificationlimitations due to the quality of observed inflow data during the winter and the uncertain simulation of soilmoisture patterns.