KSCE Journal of Civil Engineering

, Volume 23, Issue 12, pp 5257–5265 | Cite as

Feasible Ranges of Runoff Curve Numbers for Korean Watersheds Based on the Interior Point Optimization Algorithm

  • Jin-Young Lee
  • Nam Won Kim
  • Tae-Woong Kim
  • Muhammad JehanzaibEmail author
Water Resources and Hydrologic Engineering


Rainfall runoff is a complex phenomenon in nature. It differs from place to place due to different topographical features and rainfall patterns. The Natural Resources Conservation Service - Curve Number (NRCS-CN) is a well-adopted model to account for direct runoff volume from storm events. There are several studies on determining the initial abstraction and the CN from observed rainfall-runoff data; however, few studies demonstrate their statistical characteristics. The major aim of this study is to determine the feasible range and the confidence intervals of the CN. We examined 660 rainfall-runoff events collected from six medium sized watersheds in South Korea. The interior point optimization algorithm was adopted to ascertain the optimum value of CN and the initial abstraction coefficient (λ). The obtained results show that the CN value ranged from 45 to 90 and the average λ = 0.12 was best suited for Korean watersheds. The estimated confidence intervals were highly significant and strongly recommended for Korean watersheds.


initial abstraction interior point optimization NRCS-curve number confidence interval 


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This research was supported by grants from the Strategic Research Project (20180374-101) funded by the Korea Institute of Civil Engineering and Building Technology and the Disaster and Safety Management Institute (MOIS-DP-2015-05) funded by Ministry of the Interior and Safety of Korean Government. The corresponding author would like to acknowledge the Higher Education Commission (HEC) of Pakistan and the Government of Pakistan for granting a scholarship to Muhammad Jehanzaib to pursue his PhD degree from Hanyang University, South Korea.


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Copyright information

© Korean Society of Civil Engineers 2019

Authors and Affiliations

  1. 1.Dept. of Civil and Environmental EngineeringHanyang UniversitySeoulKorea
  2. 2.Dept. of Land, Water and Environment ResearchKorea Institute of Civil Engineering and Building TechnologyGoyangKorea
  3. 3.Dept. of Civil and Environmental EngineeringHanyang UniversityAnsanKorea

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