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*.wet

Purpose

The wetland group has two input files declared in type input_res (src/input_file_module.f90):

  • wetland.wet is the wetland object table. One record per wetland, naming the initial-condition set, hydrology profile, release rule, sediment profile, nutrient profile, and weir profile that apply.
  • hydrology.wet is the wetland hydrology database. One record per named hydrology profile. The geometry is HRU-relative (fraction of HRU area, depth in mm) rather than absolute area and volume as for reservoirs.

Wetlands reuse the reservoir sediment, nutrient, weir, and initial-condition databases. The wetland records in wetland.wet point at the same sediment.res, nutrients.res, weir.res, and initial.res tables described in reservoir.res.

Source

wetland.wet

Header lines: 2. The reader skips a title line and a column-header line, then reads one record per wetland with list-directed I/O. The first integer on each record is the wetland id (used as the index into wet_dat_c). The remaining columns are read into type reservoir_data_char_input in declaration order (the same type used by reservoirs).

# Field Type Description
1 id int wetland id. Used as the array index into wet_dat_c
2 name char(25) wetland name
3 init char(25) initial-state pointer. Cross-walks with init in initial.res
4 hyd char(25) hydrology pointer. Cross-walks with name in hydrology.wet
5 release char(25) release rule pointer (decision-table name)
6 sed char(25) sediment pointer. Cross-walks with name in sediment.res
7 nut char(25) nutrient pointer. Cross-walks with name in nutrients.res

The example dataset writes a trailing WEIR column. The base type has six character fields (name, init, hyd, release, sed, nut). A weir pointer is held in the extension type reservoir_data (character (len=25) :: weir). The list-directed reader for wetland.wet does not consume a separate weir token into the base record; the source links wetland weirs through dedicated reservoir-conditions input. See the Important note below.

Example

refdata/Osu_1hru/wetland.wet:

wetland.       wet: written by SWAT+ edi############for SWAT+ rev.60.5.4
     id                name        init         hyd         rel         sed         nut        WEIR
       1          paddy0001    initwet2       paddy        weir     sedwet1     nutwet1       weir1

Notes:

  • The title line in this dataset is partially corrupted ("wetland. wet:"). The reader skips it as a single text line, so the content does not matter as long as it stays on one line.
  • The rel column value weir is matched against decision-table names. If no match exists in res_rel.dtl (or in the ctbl_ conditional tables), the wetland will be flagged as missing a release rule.

hydrology.wet

Header lines: 2. The reader skips a title line and a column-header line, then reads one record per hydrology profile with list-directed I/O. Records are read into wet_hyddb (an array of type wetland_hyd_data) in declaration order.

# Field Type Units Default Description
1 name char(25) none "default" hydrology profile name
2 psa real fraction 0.0 fraction of HRU area at the principal spillway. Surface-inlet riser flow starts at this level
3 pdep real mm 0.0 average water depth at the principal spillway
4 esa real fraction 0.0 fraction of HRU area at the emergency spillway. Overflow into the ditch starts at this level
5 edep real mm 0.0 average water depth at the emergency spillway
6 k real mm/hr 0.01 hydraulic conductivity of the wetland bottom
7 evrsv real none 0.7 wetland evaporation coefficient
8 acoef real none 1.0 volume-surface area coefficient for HRU impoundment
9 bcoef real none 1.0 volume-depth coefficient for HRU impoundment
10 ccoef real none 1.0 volume-depth coefficient for HRU impoundment
11 frac real none 0.5 fraction of HRU that drains into the impoundment

The reader fills defaults when fields are zero or non-positive:

  • If psa <= 0, sets psa = 0.08 * wet_hyd(ires)%pdep (uses the previously initialized wet_hyd, not the just-read wet_hyddb).
  • If esa <= 0, sets esa = 1.5 * wet_hyd(ires)%psa.
  • If evrsv <= 0, sets evrsv = 0.6.

Example

refdata/Osu_1hru/hydrology.wet:

hydrology.wet: written by SWAT+ editor v2.2.0 on 2023-03-22 04:25 for SWAT+ rev.60.5.4
name                    hru_ps         dp_ps        hru_es         dp_es             k          evap   vol_area_co      vol_dp_a      vol_dp_b      hru_frac  
paddy                     1.00        150.00         1.00        150.00           0.5           0.75          1.00         1.00         1.00          1.0

Editor headers hru_ps, dp_ps, hru_es, dp_es, evap, vol_area_co, vol_dp_a, vol_dp_b, hru_frac correspond to source fields psa, pdep, esa, edep, evrsv, acoef, bcoef, ccoef, frac. Column order is what matters.

  • reservoir.res and initial.res. Shared tables. wetland.wet records point at initial.res names, and the sediment, nutrient, and weir lookups use the same databases as reservoirs.
  • HRU connectivity. Each wetland is attached to an HRU; the geometry in hydrology.wet is expressed as fractions of HRU area.

Important

Potential bug. wet_read_hyd applies its default fallbacks for psa and esa using values from wet_hyd (the runtime array), not from wet_hyddb (the array being populated). The two arrays are allocated independently; wet_hyd is sized by the number of wetland objects, wet_hyddb is sized by the number of database records. When the read loop hits a record whose psa is zero, the fallback expression wet_hyddb(ires)%psa = 0.08 * wet_hyd(ires)%pdep indexes wet_hyd with the database record index ires, not the wetland-object index. If wet_hyd has not been initialized at this point in the start-up sequence, this fallback can compute against zero or stale data. See src/wet_read_hyd.f90 lines 55 to 57.