Spatio-temporal distribution for infiltration rate over horizontal heterogeneous field

摘要

Infiltration model in heterogeneous areas is developed during rainfall and recession. The soil properties of spatially uneven field are assumed to be uniform along the vertical direction but are allowed to vary in the horizontal direction and only the saturated hydraulic conductivity among all the soil parameters is variable along horizontal direction , which is described as lognormal distribution. The soil surface is separated as the saturated and unsaturated region due to rainfall process. The vertically integrated Darcy law and continuity equation are the two basic equations to obtain the analytic approximation of infiltration rate based on the rectangular profile assumption of Green-Ampt model. The spatio-temporal varying mean infiltration recharge is derived as a function of depth , time and saturated hydraulic conductivity over unsaturated and saturated region. The model results show it is helpful to consider the infiltration recharge hysteresis of different soil depth in heterogeneous field during rainfall and redistribution.