Study on modeling infiltration responses of different soils under ponding conditions

Based on the infiltration model under ponding condition introduced by Parlange, infiltration responses of different soils under ponding conditions were numerically studied for 10 hours in this paper. Results modeled by Green-Ampt model were used for comparison under rainfall rate 20 cm/h. It has been found that the cumulative infiltration shows positive relativity with the saturated hydraulic conductivity. Actual infiltration rate curve was divided into 2 period, falling rate-state infiltrability phase and steady-state infiltrability phase. As for one type of soil, the cumulative infiltration varies widely under 4 designed cases, which is induced by the difference of ponding depth. Comparison was also made with the results modeled by the equation I=K_st. It has been also found that results of loamy sand and sandy loam modeled by I=K_st were close to those modeled by Parlange model under ponding conditions, except case 1. If ponding depth is less smaller (such as less than 3cm), results modeled by Green-Ampt model under heavy rainfall condition are close to those modeled under ponding conditions by Parlange model. Wetting front varies widely as well, from which it can be concluded infiltration capacity of different soils under ponding conditions as following: loamy sand>;sandy loam>;loam>;clay.