Water Resources Management

, Volume 19, Issue 1, pp 37-62

First online:

Field Applicability of the SCS-CN-Based Mishra–Singh General Model and its Variants

  • S. K. MishraAffiliated withWater Res. Dev. Training Centre, Indian Institute of Technology
  • , M. K. JainAffiliated withNational Institute of Hydrology
  • , P. K. BhunyaAffiliated withNational Institute of Hydrology Email author 
  • , V. P. SinghAffiliated withDepartment of Civil and Environmental Engineering, Louisiana State University

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The general soil conservation service curve number (SCS-CN)-based Mishra and Singh (Mishra and Singh, 1999, J. Hydrologic. Eng. ASCE, 4(3), 257–264) model and its eight variants were investigated for their field applicability using a large set of rainfall-runoff events, derived from a number of U.S. watersheds varying in size from 0.3 to 30351.5 ha, grouped into five classes based on the rainfall magnitude. The analysis based on the goodness of fit criteria of root mean square error (RMSE) and error in computed and observed mean runoff revealed that the performance of the existing version of the SCS-CN method was significantly poorer than that of all the model variants on all the five data sets with rainfall ≤ 38.1 mm. The existing version showed a consistently improved performance on the data with increasing rainfall amount, but greater than 38.1 mm. The one-parameter modified SCS-CN method (a = 0.5 and λ = a median value) performed significantly better than the existing one on all the data sets, but far better on rainfall data less than 2 inches. Finally, the former with λ = 0 was recommended for routine field applications to any data set.


agriculture research service ars water database curve number initial abstraction coefficient soil conservation service SCS-CN method