In the present version of this model, only clearcutting and partial cutting can be handled and it is assumed a single layer canopy structure. Two point linear temperature partitioning is used to differentiate the incoming precipitation into rain and snow. A single layer snowpack energy and mass balance model is utilized with finite difference solution to simulate snow accumulation and melt when the incoming precipitation has snow component or there is snow on the ground. Interception is described as a linear function with leaf area index through the storage capacity. Subsurface water movement is based on the Dupuit assumption of slope-parallel saturated flow through a limited depth of soil over a relative impermeable layer of parent material or bedrock.
Overland flow is assumed only to occur when the ground is saturated.
Some exchange between deep groundwater and the subsurface layer is incorporated. Intercell water movement is modeled with a kinematic continuity equation and combined subsurface and overland flow equation are solved to route water from one element to another. Landslide occurrence is simulated with infinite slope model using the hydrological results. Upon any slope instability, the possible runout path or debris flow is simulated using the local slope, channel geometry and mass decay function. Sediment transport out off the watershed by streamflow is based on the rating curve to discharge.