observable variable

• actual evaporation
• actual soil evaporation
• canopy storage of solute
• potential 'wet-canopy' evaporation
• potential root water uptake
• soil temperature
• soil water content
• solute concentration in macropores
• solute concentration in micropores
• solute concentration in soil solution
• solute concentration in solid phase
• water flux entering a soil layer or domain
• water table height

internal variable

• canopy interception
• direct throughfall
• drainage rate
• drip throughfall
• effective saturation in macropores
• effective saturation in micropores
• hydraulic conductivity
• hydraulic conductivity of macropores
• hydraulic conductivity of micropores
• hydraulic head
• infiltration in macropores
• infiltration in micropores
• leaf area index
• lower boundary condition
• maximum possible water flux to soil surface
• maximum water pressure head
• potential 'dry-canopy' transpiration
• potential soil evaporation
• root depth
• root water uptake sink
• sink term in solute transport equation (biodegradation)
• soil water content in macropores
• soil water pressure head
• soil water pressure head of micropores
• solute concentration in net rainfall
• solute concentration in solid phase, macropores
• solute concentration in water...
• solute store in micropores
• source/sink term
• total drainage rate
• water stored in the canopy