Importance of Storm Type and Initial Loss Value for Flood Discharge Estimation

Available flood discharge data has a significant role in the procedure of flood control and management. In sites with a lack of data, a simulation model with the synthetic and estimated data is recommended. In this study a rainfall-runoff model (HEC-HMS) based on SCS (curve number) and flood routing (lag-trend) methods have been applied for a watershed situated in the north of Neyshabour, Northeast of Iran. The effects of several storm patterns and initial losses (0.2 & 0.05) have been studied for flood estimation. The results indicated that for a storm pattern of type IV and initial losses of 0.2, the estimated peak flood had more accuracy among patterns. However with this model 53% of 15 observed flood peak data is acceptable. Other result showed that the SCS method has less accuracy and it is not recommended for a watershed like north Neyshaboor flood management and should be calibrated.