Evaporation

Evaporation can occur for standing water on subcatchment surfaces, for subsurface water in groundwater aquifers, and water held in storage units. Evaporation rates can be stated as: 

·       A single constant value

·       A set of monthly average values 

·       A user-defined time series of daily values

·       values computed from the daily temperatures contained in an external climate file

·       daily values read directly from an external climate file.

If rates are read directly from a climate file, then a set of monthly pan coefficients should also be supplied to convert the pan evaporation data to free water-surface values. An option is also available to allow evaporation only during periods with no precipitation.