UNCERTAINTY ON A SHORT-TERM FLOOD FORECAST WITH RAINFALL-RUNOFF MODEL

摘要

Precipitation forecast has been become a useful asset for flood prediction using rainfall-runoff model. An uncertainty that appears on the forecast affects accuracy of flood prediction, added to that is which possessed in the rainfall-runoff model. The case is in Shichikashuku Dam basin in Japan. The precipitation forecast is a product of short range forecast of Japan operational numerical weather prediction based on Mesoscale Model (MSM) and Regional Scale Model (RSM). The rainfall-runoff model based on distributed tank model. This research estimates total uncertainty by quantifying mean error and standard deviation on the precipitation and discharge forecast. The result has shown that the precipitation forecast is more uncertain than discharge's. Uncertainty is significantly increased after twelve hour and draws a common characteristic between both models.