Climate parameters required : rainfall amount and duration, solar radiation, maximum and minimum air temperatures, dew point temperatures. If actual measured data is not available the model uses CLIGEN to generate climate data.

Upland Input: Surface and subsurface runoff.

Interception: Vegetation canopy and litter layer interception.

• Interception computed using modified form of Thomas & Beasley (1986) equation. Variables that determine interception amount are: LAI, canopy storage capacity, and rainfall amount.
• Precipitation falling through the canopy is available for litter interception. Litter interception is a function of litter storage capacity and litter layer depth.

Evaporation and transpiration:

• Evapotranspiration is computed in two stages. Intercepted water on the vegetation canopy evaporates first. Transpiration proceeds after all intercepted water is lost.
• Potential evapotranspiration is computed using a modified form of the Penman-Monteith equation (Running & Coughlan, 1988).
• Transpiration losses are controlled by stomatal resistance.
• Radiation that reaches the mineral soil surface drives the soil surface evaporation. Soil evaporation is computed in two stages following Gardner & Hillel (1962).
• The extinction of radiation through the vegetative canopy is computed using Beer-Lambert Law.

Infiltration and vertical drainage:

• Infiltration is computed using the modified form of Green-Ampt equation (Stone et al., 1994).
• Vertical drainage occurs when soil moisture exceeds the field capacity of a soil layer.
• Influence of a shallow water table on soil moisture of an overlaying soil layer is considered.
• Upward flux from the shallow water table to meet evapotranspiration losses from overlaying soil layers is simulated using the Darcy-Buckingham equation as decsribed by Skaggs (1978).

Surface runoff:

• Surface runoff forms simulated - infiltration excess, saturation excess, and return flow.
• Surface runoff entering the riparian area from upland contributing areas is routed downslope.

Subsurface flow:

• Lateral subsurface flow is assumed to occur when soil moisture exceeds the field capacity and there is sufficient hydraulic gradient to move the water.
• Lateral flow is simulated using Darcy's equation.
• Lateral subsurface flow can be released as return flow if the soil profile downslope is already saturated.