GWF-RCH

Structure of Blocks

FOR EACH SIMULATION

    BEGIN OPTIONS
      [FIXED_CELL]
      [AUXILIARY <auxiliary>]
      [AUXMULTNAME <auxmultname>]
      [BOUNDNAMES]
      [PRINT_INPUT]
      [PRINT_FLOWS]
      [SAVE_FLOWS]
      [TS6 FILEIN <ts6_filename>]
      [OBS6 FILEIN <obs6_filename>]
    END OPTIONS

    BEGIN DIMENSIONS
      MAXBOUND <maxbound>
    END DIMENSIONS

FOR ANY STRESS PERIOD

    BEGIN PERIOD <iper>
      <cellid> <recharge> [<aux(naux)>] [<boundname>]
      <cellid> <recharge> [<aux(naux)>] [<boundname>]
      ...
    END PERIOD

Explanation of Variables

Block: OPTIONS

• FIXED_CELL indicates that recharge will not be reassigned to a cell underlying the cell specified in the list if the specified cell is inactive.

• auxiliary defines an array of one or more auxiliary variable names. There is no limit on the number of auxiliary variables that can be provided on this line; however, lists of information provided in subsequent blocks must have a column of data for each auxiliary variable name defined here. The number of auxiliary variables detected on this line determines the value for naux. Comments cannot be provided anywhere on this line as they will be interpreted as auxiliary variable names. Auxiliary variables may not be used by the package, but they will be available for use by other parts of the program. The program will terminate with an error if auxiliary variables are specified on more than one line in the options block.

• auxmultname name of auxiliary variable to be used as multiplier of recharge.

• BOUNDNAMES keyword to indicate that boundary names may be provided with the list of recharge cells.

• PRINT_INPUT keyword to indicate that the list of recharge information will be written to the listing file immediately after it is read.

• PRINT_FLOWS keyword to indicate that the list of recharge flow rates will be printed to the listing file for every stress period time step in which “BUDGET PRINT” is specified in Output Control. If there is no Output Control option and “PRINT_FLOWS” is specified, then flow rates are printed for the last time step of each stress period.

• SAVE_FLOWS keyword to indicate that recharge flow terms will be written to the file specified with “BUDGET FILEOUT” in Output Control.

• TS6 keyword to specify that record corresponds to a time-series file.

• FILEIN keyword to specify that an input filename is expected next.

• ts6_filename defines a time-series file defining time series that can be used to assign time-varying values. See the “Time-Variable Input” section for instructions on using the time-series capability.

• OBS6 keyword to specify that record corresponds to an observations file.

• obs6_filename name of input file to define observations for the RCH package. See the “Observation utility” section for instructions for preparing observation input files. Table ref{table:gwf-obstypetable} lists observation type(s) supported by the RCH package.

Block: DIMENSIONS

• maxbound integer value specifying the maximum number of recharge cells that will be specified for use during any stress period.

Block: PERIOD

• iper integer value specifying the starting stress period number for which the data specified in the PERIOD block apply. IPER must be less than or equal to NPER in the TDIS Package and greater than zero. The IPER value assigned to a stress period block must be greater than the IPER value assigned for the previous PERIOD block. The information specified in the PERIOD block will continue to apply for all subsequent stress periods, unless the program encounters another PERIOD block.

• cellid is the cell identifier, and depends on the type of grid that is used for the simulation. For a structured grid that uses the DIS input file, CELLID is the layer, row, and column. For a grid that uses the DISV input file, CELLID is the layer and CELL2D number. If the model uses the unstructured discretization (DISU) input file, CELLID is the node number for the cell.

• recharge is the recharge flux rate (LT^-1). This rate is multiplied inside the program by the surface area of the cell to calculate the volumetric recharge rate. If the Options block includes a TIMESERIESFILE entry (see the “Time-Variable Input” section), values can be obtained from a time series by entering the time-series name in place of a numeric value.

• aux represents the values of the auxiliary variables for each recharge. The values of auxiliary variables must be present for each recharge. The values must be specified in the order of the auxiliary variables specified in the OPTIONS block. If the package supports time series and the Options block includes a TIMESERIESFILE entry (see the “Time-Variable Input” section), values can be obtained from a time series by entering the time-series name in place of a numeric value.

• boundname name of the recharge cell. BOUNDNAME is an ASCII character variable that can contain as many as 40 characters. If BOUNDNAME contains spaces in it, then the entire name must be enclosed within single quotes.

Example Input File

Example 1

    BEGIN OPTIONS
      AUXILIARY var1 var2 mult
      PRINT_INPUT
      PRINT_FLOWS
      SAVE_FLOWS
      BOUNDNAMES
      TS6 FILEIN recharge_rates.ts
      # Note: Time-series file recharge_rates.ts defines time series rch_1
      AUXMULTNAME mult
    END OPTIONS
    
    BEGIN DIMENSIONS
      MAXBOUND  10
    END DIMENSIONS
    
    BEGIN PERIOD 1
      # Lay  Row  Col  Rate   Var1  Var2   mult  BoundName
         1    1    1   rch_1   1.0   2.0     1.0       Rch-1-1
         1    1    2   rch_1   1.1   2.1     1.0       Rch-1-2
         1    1    3   rch_1   1.2   2.2     0.5
         1    2    1   rch_1   1.3   2.3     1.0       Rch-2-1
         1    2    2   rch_1   1.4   2.4     1.0       Rch-2-2
         1    2    3   rch_1   1.5   2.5     1.0
         1    2    4   rch_1   1.6   2.6     0.5
         1    3    1   rch_1   1.7   2.7     1.0
         1    3    2   rch_1   1.8   2.8     1.0
         1    3    3   rch_1   1.9   2.9     1.0
    END PERIOD

Example 2

    BEGIN OPTIONS
      AUXILIARY var1 var2 mymult
      READASARRAYS
      PRINT_INPUT
      PRINT_FLOWS
      SAVE_FLOWS
      AUXMULTNAME mymult
    END OPTIONS
    
    BEGIN PERIOD 1
    
      # For this model, the absence of an IRCH array causes
      # recharge to apply to model layer 1. To make recharge
      # apply to layer 2 instead, the following lines
      # (uncommented) could be used:
      # IRCH
      #   constant 2
    
      # recharge rate
      RECHARGE
        constant 0.0040
    
      # auxiliary variable (var1) array
      var1
        constant 100.
    
      # auxiliary variable (var2) array
      var2
        constant 0.
    
      # auxiliary variable (mymult) array
      # Because ``AUXMULTNAME mymult'' was specified in the
      # options block, the MYMULT array will be used to multiply
      # the values in the RECHARGE array
      MYMULT
        INTERNAL FACTOR  1.0
          0.5  1.0  1.0  0.5
          1.0  1.0  1.0  1.0
          0.5  1.0  1.0  0.5
    
    END PERIOD

Available Observation Types

Stress Package	Observation Type	ID1	ID2	Description
RCH	rch	cellid or boundname	--	Flow to the groundwater system through a recharge boundary or a group of recharge boundaries.

Example Observation Input File

    BEGIN OPTIONS
      PRINT_INPUT
    END OPTIONS
    
    BEGIN CONTINUOUS FILEOUT my_model.rch.csv
      rch1-1    RCH   Rch-1-1
      rch1-2    RCH   Rch-1-2
      rch2-1    RCH   Rch-2-1
      rch2-2    RCH   Rch-2-2
      rch2-3    RCH   1  2  3
    END CONTINUOUS