Two universal runoff yield models: SCS vs. LCM

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 have 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 the LCM model and between parameters (S) of the SCS model, respectively. Parameters (R, r) of the LCM can be determined using the research results of the SCS model parameters. (3) LCM model parameters (R, r) can be easily obtained by field experiments, while SCS parameters (S) are difficult to measure. Therefore, parameters (R, r) of the LCM model also can provide the foundation for the 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 terms of a Taylor series expansion of the LCM model describe the same relationship, which is worth further study.

A Flexible Framework HydroInformatic Modeling System—HIMS

“…The runoff generation modular contains the SCS-CN, the Green-Ampt equation, Water 2018, 10, 962 3 of 17 the LCM developed by Liu et al [19,20], and the Time-Variant Gain Model by Xia et al [21]. Though both the SCS and LCM indicate reciprocal linear relationship between precipitation losses and total precipitation volume [22], the LCM equation is much more advanced than the SCS-CN method when it comes to the utilization at un-gauged areas. The key parameters of SCS are hard to obtain, while the parameters of LCM are easily obtained with field experiments.…”

“…The key parameters of SCS are hard to obtain, while the parameters of LCM are easily obtained with field experiments. Therefore, LCM is much more suitable for estimating runoff of the un-gauged study areas [22]. Hillslope flow routing contains the kinematic wave equation and the unit hydrograph, which are used to calculate the flow velocity, concentration time from hill-slopes to the channel, and/or the flow concentration process of the sub-watershed/grid cell, including peak flow, peak lag time, and duration of the grid cell.…”

“…In the semi-arid areas, it is recommended to use the LCM as the runoff generation equation and the Muskingum equation as the channel routing model based on the literature review [22][23][24] for setting the HIMS model structure. It makes senses as the HIMS model has the structure of the combined runoff generation mechanisms and LCM is an empirical model developed on the base of the observed data from the semi-arid areas including the Lhasa River basin [21].…”

Rainfall–runoff estimation using SCS–CN and GIS approach in the Pappiredipatti watershed of the Vaniyar sub basin, South India

“…The Soil conversations Service-Curve Number approach is based on the water balance calculation and two fundamental hypotheses had been proposed (Jun et al 2015). The first suggestion states about that the ratio of the real quantity of direct runoff to the maximum possible runoff is equal to the ratio of the amount of real infiltration to the quantity of the potential maximum retention.…”

Rainfall-runoff modeling, parameter estimation and sensitivity analysis in a semiarid catchment

“…It was discovered that rainfall infiltration and runoff is not only related to rainfall intensity, but also to soil moisture content. Using theoretical analyses and numerical simulations, Li et al (2014) compared the SCS and LCM models. They found that SCS model is a linear representation of LCM model, and the latter can reflect nonlinear runoff.…”