Fast method for estimating soil infiltrability with modified Green-Ampt model

To quantify the soil infiltrability is of great importance for the study of the hydrological process and related researches and applications. A fast method for estimating soil infiltrability was proposed in this study based on the horizontal soil column measurement method and the modified Green-Ampt model according to the proportional relationship between the soil infiltrability estimated with the piston model and that calculated with the modified Green-Ampt one. The newly introduced fast model for estimating soil infiltrability was the simplification of the modified Green-Ampt infiltration model with relatively high accuracy. Comparisons were made among the results estimated with the three calculation models, which were the piston model, the modified Green-Ampt model and the fast estimation model. The results showed that the soil infiltrability estimated with the fast estimation model was very close to that calculated with the modified Green-Ampt model. The relative errors of these three methods were calculated based on the mass balance principle which were 11.5% for the piston model, 0.66% for the modified Green-Ampt model and 2.68% for the fast estimation model. The fast estimation method introduced in this study, combined with the horizontal soil column measurement method is applicable to laboratory studies of soil infiltrability. This method supplies a useful tool for the study of hydrologic circulation/overland flow and other relative fields.