The Evaporation page of the Climatology Editor dialog is used to supply evaporation rates for a study area. There are six choices for specifying these rates; for all but the No Evaporation option, check the Evaporate Only During Dry Periods? box to allow evaporation only during periods with no precipitation. You may also define a Monthly Soil Recovery Pattern to allow the infiltration recovery rate to be adjusted by a fixed amount on a monthly basis to account for seasonal variation in evaporation rates. The Evaporation Types are as follows:

• No Evaporation: Use this choice if there is no evaporation for this scenario.
• Constant Evaporation: Use this choice if evaporation remains constant over time. Enter the value in the edit box provided.
• Time Series Evaporation: Select this choice if evaporation rates will be specified in a time series. Note that for each time specified in the time series, the evaporation rate remains constant at the value supplied for that date until the next date in the series is reached (i.e., interpolation is not used on the series).
• Climate File: This choice indicates that daily evaporation rates will be read from the same climate file that was specified for temperature. Enter values for monthly pan coefficients in the data grid provided to convert the pan evaporation data to free water-surface values.
• Climate File - Temperatures: Hargreaves’ method will be used to compute daily evaporation rates from the daily air temperature record contained in the external climate file specified on the Temperature page of the dialog. This method also uses the site’s latitude, which can be entered on the Snowmelt page of the dialog even if snow melt is not being simulated.
• Monthly Evaporation: Use this choice to supply an average rate for each month of the year. Enter the value for each month in the data grid provided. Note that rates remain constant within each month.