GWT-MST

Structure of Blocks

FOR EACH SIMULATION

    BEGIN OPTIONS
      [SAVE_FLOWS]
      [FIRST_ORDER_DECAY]
      [ZERO_ORDER_DECAY]
      [SORPTION <sorption>]
    END OPTIONS

    BEGIN GRIDDATA
      POROSITY [LAYERED]
            <porosity(nodes)> -- READARRAY
      [DECAY [LAYERED]
            <decay(nodes)> -- READARRAY]
      [DECAY_SORBED [LAYERED]
            <decay_sorbed(nodes)> -- READARRAY]
      [BULK_DENSITY [LAYERED]
            <bulk_density(nodes)> -- READARRAY]
      [DISTCOEF [LAYERED]
            <distcoef(nodes)> -- READARRAY]
      [SP2 [LAYERED]
            <sp2(nodes)> -- READARRAY]
    END GRIDDATA

Explanation of Variables

Block: OPTIONS

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

  • FIRST_ORDER_DECAY is a text keyword to indicate that first-order decay will occur. Use of this keyword requires that DECAY and DECAY_SORBED (if sorption is active) are specified in the GRIDDATA block.

  • ZERO_ORDER_DECAY is a text keyword to indicate that zero-order decay will occur. Use of this keyword requires that DECAY and DECAY_SORBED (if sorption is active) are specified in the GRIDDATA block.

  • sorption is a text keyword to indicate that sorption will be activated. Valid sorption options include LINEAR, FREUNDLICH, and LANGMUIR. Use of this keyword requires that BULK_DENSITY and DISTCOEF are specified in the GRIDDATA block. If sorption is specified as FREUNDLICH or LANGMUIR then SP2 is also required in the GRIDDATA block.

Block: GRIDDATA

  • porosity is the aquifer porosity.

  • decay is the rate coefficient for first or zero-order decay for the aqueous phase of the mobile domain. A negative value indicates solute production. The dimensions of decay for first-order decay is one over time. The dimensions of decay for zero-order decay is mass per length cubed per time. decay will have no effect on simulation results unless either first- or zero-order decay is specified in the options block.

  • decay_sorbed is the rate coefficient for first or zero-order decay for the sorbed phase of the mobile domain. A negative value indicates solute production. The dimensions of decay_sorbed for first-order decay is one over time. The dimensions of decay_sorbed for zero-order decay is mass of solute per mass of aquifer per time. If decay_sorbed is not specified and both decay and sorption are active, then the program will terminate with an error. decay_sorbed will have no effect on simulation results unless the SORPTION keyword and either first- or zero-order decay are specified in the options block.

  • bulk_density is the bulk density of the aquifer in mass per length cubed. bulk_density is not required unless the SORPTION keyword is specified.

  • distcoef is the distribution coefficient for the equilibrium-controlled linear sorption isotherm in dimensions of length cubed per mass. distcoef is not required unless the SORPTION keyword is specified.

  • sp2 is the exponent for the Freundlich isotherm and the sorption capacity for the Langmuir isotherm.

Example Input File

    BEGIN OPTIONS
      SORPTION linear
      FIRST_ORDER_DECAY
    END OPTIONS
    
    BEGIN GRIDDATA
      POROSITY
        CONSTANT  0.1
      DECAY
        CONSTANT 0.001
      DECAY_SORBED
        CONSTANT 0.001
      BULK_DENSITY
        CONSTANT 1.
      DISTCOEF
        CONSTANT 0.01
    END GRIDDATA