SWAT+ is able to run at the following time steps:

The print.prt file is formatted differently than most other SWAT+ input files (see figure below). In line three, there are several variables for controlling the time period to be printed. In line five, the user can specify the number of print intervals for average annual output. In line seven, the user can select to have output files printed in a specific file format (in addition to the default *.txt output files). In line 9, the user can control the printing of outputs for soils and management as well as flow duration curves. In lines 11 to 90, there is a list of outputs for different spatial levels and objects that can be printed at daily, monthly, yearly, and average annual time steps. A description of the output files is provided in the section.

SWAT+ is able to end a simulation at any day of the year. This option can for example be useful, if the user wishes to simulate hydrological years instead of calendar years.

Some simulations will need a warm-up or equilibration period. The use of a warm-up period becomes more important as the simulation period of interest shortens. For 30-year simulations, a warm-up period is optional. For a simulation covering 5 years or less, a warm-up period is recommended.

There are three files that control the settings for a simulation run:

• object.cnt specifies the land area and the total area (including ponds and reservoirs) of the watershed and the counts of all spatial objects in a simulation,

• time.sim controls the simulation time period and time step, and

• print.prt controls which output files will be printed for a simulation.

An additional, optional file, object.prt, allows the user to print selected output for individual spatial objects.

If aa_int_cnt = 0, the model will print average annual output for the entire period. If aa_int_cnt > 0, the end years of the print intervals have to be specified by the user by listing them in chronological order in the same line as aa_int_cnt.

The object.prt file is commonly used to:

• Print daily channel outflow to compare to observed streamflow a stream gage

• Print daily flow to a file that can be read in as a point source from another SWAT+ simulation

The only timestep output can be printed at using this file is daily. A description of the output files is provided in the SWAT+ Output Files section.

The table below lists the objects that are listed in the first column of this section of the print.prt file. For each of these objects, output can be printed at daily, monthly, yearly, and average annual time steps by entering y (=yes) or n (=no) in the following four columns.

Output can be printed for the following types of objects:

This parameter specifies the interval within the specified printing period.

The following hydrographs can be printed:

Soil water contents of the soil layers can be printed for all HRUs in the same file by setting obj_typ_no = 0. For all other outputs, a separate object print record with a unique name has to be defined for each object.

SWAT+ is able to begin a simulation at any day of the year. This option can for example be useful, if the user wishes to simulate hydrological years instead of calendar years.