Output reference

SWAT+ writes one text file per (scope, group, interval) combination. Every output is toggled in print.prt. This section documents the file groups, their columns, and where they are written in the source.

Naming convention¶

All time-step output files follow the pattern:

<scope>_<group>_<interval>.txt

When csvout = y in print.prt, a matching .csv variant is also written.

Scopes (the spatial aggregation level):

Scope	Meaning
`hru_`	one row per Hydrologic Response Unit
`hru-lte_`	one row per low-resolution HRU (lite model)
`lsunit_`	one row per landscape unit (`ls_unit.def`)
`ru_`	one row per routing unit
`region_`	one row per region defined for regional output
`basin_`	one row, the basin-wide sum or average
`channel_`	one row per channel object (legacy `cha`)
`channel_sd` / `sd_chan`	one row per channel object (sd_channel routing)
`aquifer_`	one row per aquifer object
`reservoir_`	one row per reservoir object
`wetland_`	one row per wetland object
`recall_`	one row per recall object (point source or inlet)
`crop_yld_`	one row per HRU per harvested plant

Groups (the variable family):

Group	Meaning
`_wb`	water balance (precipitation, ET, runoff, percolation, storage)
`_nb`	nutrient balance (mineral and organic N and P pools)
`_ls`	losses from the landscape (sediment, nutrient yields)
`_pw`	plant and weather (LAI, biomass, yield, temperature, stress)
`_cha`	channel routing (legacy: flow, sediment, nutrients)
`_sd_cha`	sd_channel routing (water body storage, in, out)
`_aqu`	aquifer storage and fluxes
`_res`	reservoir storage and fluxes
`_pest`	pesticide
`_salt`	salt ions
`_cs`	constituents
`_carbon`	soil carbon pools
`_chanbud`	channel sediment budget
`_chamorph`	channel morphology

Intervals (the time aggregation):

Suffix	Meaning
`_day`	one row per simulated day
`_mon`	one row per month
`_yr`	one row per year
`_aa`	one row, average annual over the print window

Each interval is enabled independently in print.prt. A row in print.prt named hru_wb with y in the avann column produces hru_wb_aa.txt; with y in the daily column it also produces hru_wb_day.txt. The file is opened in output_landscape_init.f90 only if the matching switch is y.

Per-group pages¶

Naming convention. The full grammar and the print.prt mapping.
Water balance. The *_wb_*.txt columns: precipitation, ET, runoff, percolation, soil and snow storage.
Channel and sediment. The legacy channel_*.txt and the sd_channel channel_sd_*.txt columns, including sediment and nutrient routing.
Aquifer, reservoir, plant. The aquifer_*.txt, reservoir_*.txt, crop_yld_*.txt, and plant/water-stress (*_pw_*.txt) columns.
Checker and diagnostics. The always-on diagnostic files: checker.out, diagnostics.out, simulation.out, files_out.out.
Post-processing helpers. The two Python scripts shipped in test/ for regression checks and CSV conversion.

Output index file¶

When SWAT+ runs, it writes a master index files_out.out listing every output file actually opened during that run. The first column is a short tag (HRU, BASIN, CHK, CHN, AQU, RES, ...) and the second column is the filename. Open files_out.out first to see exactly which outputs your print.prt produced.