Spatial soil and vegetation distribution and logging history are also read in from GIS database and assigned to each element. Vegetation characteristics such as biomass, tree height, cover density, leaf area index, and root strength are calculated based on the logging history to simulate the vegetation dynamics after cutting or noncutting. 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.