Distribution of Temperature and Precipitation in the Snowmelt Runoff Analysis

Good accuracy in snowmelt runoff analysis is needed for water resource management in snowy mountainous regions. In the present study, a distributed, as opposed to lumped, model of snowmelt calculation as well as runoff calculation is developed and applied to a mountainous basin in Japan with the catchment area of 355 km². In applying this model, observed temperature data are analyzed to obtain the actual lapse rate, which in turn gives the temperature distribution throughout the basin. For the distribution of snow precipitation the catch-ratio of the gage and dependence on the altitude is assumed and the associated constants are determined to give the best fit of the calculated runoff to the observed data. The result shows the better fitting with the runoff data as compared to the calculation without this kind of consideration.