Acta Geographica Sinica ›› 2014, Vol. 69 ›› Issue (7): 926-932.doi: 10.11821/dlxb201407005

• Orginal Article • Previous Articles     Next Articles

Two universal runoff yield models: SCS vs. LCM

Jun Li(), Changming LIU(), Zhonggen WANG, Kang LIANG   

  1. Key Laboratory of Water Cycle & Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China
  • Received:2014-04-20 Revised:2014-05-26 Online:2014-07-20 Published:2014-07-20
  • Supported by:
    National Science and Technology Support Program, No.2013BAC10B02-02;National Natural Science Foundation of China, No.41271048;The Key Project of the National Natural Science Foundation of China, No.41330529

Abstract:

Runoff calculation is one of the key components in the hydrological modeling. For a certain spatial scale, runoff is a very complex nonlinear process. Currently, the runoff yield model in different hydrological models is not unique. The Chinese LCM model and the American SCS model describe runoff at the macroscopic scale, taking into account the relationship between total actual retention and total rainfall and having a certain similarity. In this study, by comparing the two runoff yield models using theoretical analyses and numerical simulations, we found that: (1) the SCS model is a simple linear representation of the LCM model, and the LCM model reflects more significantly the nonlinearity of catchment runoff. (2) There are strict mathematical relationships between parameters (R, r) of LCM model and between parameters (S) of SCS model, respectively. Parameters (R, r) of LCM can be determined using the research results of SCS model parameters. (3) LCM model parameters (R, r) can be easily obtained by field experiments, while it is difficult to measure SCS parameters (S). Therefore, parameters (R, r) of LCM model can also provide the foundation for SCS model. (4) The SCS model has a linear relationship between the reciprocal of total actual retention and the reciprocal of total rainfall during runoff period. The one-order term of a Taylor series expansion of the LCM model describes the same relationship, which needs to be further studied.

Key words: rainfall infiltration, runoff calculation, nonlinearity, the SCS model, the LCM model