Evaporation

Evaporation can occur for standing water on subcatchment surfaces, for subsurface water in groundwater aquifers, and for 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.