Probabilistic estimation of design runoff curve number: a case study for Shakkar river watershed, India

摘要

In this study, one-day, two-day and three-day maximum surface runoff were calculated. The curve number (CN) are dealt with as arbitrary factors with the CN connected with antecedent moisture condition (AMC-II) representing 50%, AMC-I, AMC-III representative of 10% and 90% CN value, respectively. The maximum surface runoff for one, two and three-day was fitted with three probability distribution [log-normal (LN), Gumbel and log-Pearson-III]. Out of three probability distribution, log-Pearson-III showed the best fit for the data. The maximum surface runoff (1/2/3 day) was estimated at 2, 5, 10, 25, 50, 100 and 200 years return periods. For all the return periods and rain durations, the design CN runoff and conventional design runoff found satisfactory performance. Probabilistic estimation of one, two and three-day maximum runoff is important for safe and cost effective planning and design of surface runoff storage system.