抄録
This paper described Runoff Characteristics in drought period based on Minimum monthlyPrecipitation and Continuous dry days. Therefore, we conducted during September 2005 to August 2007 in the upper Iwaki catchment, Japan with distributed snowmelt runoff model. As the result of the analysis with Continuous dry days, the runoff analysis shows precipitation in July and August have an impact on lack of river discharge, but shows precipitation in June don't have an impact on river discharge because snow contribute to discharge. Moreover, river discharge has decreased about 5m3/s when continuous dry days have 21 days in July. So these shows drought event probability get higher when timing of the appearance of continuous dry days are increasing distance from snowmelt season.