Infiltration is calculated using the Green and Ampt formulation. It also draws animation maps at the basin level. Input rainfall is allowed to vary in space and time. Major components of the model include interception, infiltration, and surface runoff routing. Interception is a process whereby rainfall is retained by vegetation.
Interception is estimated using an empirical three parameter model.
Infiltration is the process whereby rainfall or surface water is pulled into the soil by capillary and gravity forces. The Green and Ampt equation with four parameters is applied to model the event-based infiltration. For continuous soil moisture accounting, redistribution of soil moisture can also be simulated whenever the non-intercepted rainfall intensity falls below the saturated hydraulic conductivity of the soil. The redistribution option requires two more soil hydraulic parameters. Excess rainfall becomes surface runoff and is routed as overland flow and subsequently as channel flow.