Abstract
Mathematical models for defining permeability of unsaturated flow and purification coefficient of muddy water in forest-soil layer are proposed based on the pF test. The models are applied to two-dimensional soil layer, in which effluents of water and fine suspended material are calculated numerically by coupling kinematic wave equation and Richards equation for surface flow and unsaturated seepage flow, respectively. A model test is performed for 2 runs, from which it is indicated that the concentration of suspended sediment is considerably reduced by infiltrating the muddy water into forest-soil layers. The numerical computation based on the present modelling agrees reasonably well with the laboratory test.
