A Determination of Peak- Flood using Different Curve Number Methods (Case Study, Central Alborz Area)

Soil conservation service-curve number (SCS-CN) method is one of the most employed methods for computing discharge as well as surface run off from watersheds. Recent studies show that this muchused method is susceptible to difference in curve number. As a result, much caution is recommended in its application. In this research the above-mentioned method was used and it was found that the asymptotic method would give a better SCS Table method for determining curve number, Results also reveal least peak-flood differences between observed and calculated discharge in the asymptotic method. The discharge while using SCS Table method in different antecedent moisture conditions shows a larger difference with the observed discharge.