The SCS curve number method is a simiple, widely used and efficient method for determining the approxient amount of runoff from a rainfall even in a particular area Although the method is designed for a single storm event, it can be scaled to find average annual runoff values The stat requirments for this method are very low, rainfall amountThis method should be used only if the weighted CN is greater than 40 Exhibit 4I from chapter 4 of TR55 for Type I rainfall Distribution Exhibit 4IA from chapter 4 of TR55 for Type IA rainfall Distribution Exhibit 4II from chapter 4 of TR55 for Type II rainfall DistributionComputer programs provide accurate analysis methods WinTR55 also has improved routing • This chapter in TR55 contains a manual method for qqpyuick estimates if the effects of temporary detention on peak discharges – The method is based on average storage and routing effects for many structures Transportation Wv Gov Highways Engineering Manuals Drainage A1 In Total Final Pdf Tr-55...