mf6ivar.md

MODFLOW 6 INPUT VARIABLES

component	package	block	variable name	type	description
SIM	NAM	OPTIONS	CONTINUE	KEYWORD	keyword flag to indicate that the simulation should continue even if one or more solutions do not converge.
SIM	NAM	OPTIONS	NOCHECK	KEYWORD	keyword flag to indicate that the model input check routines should not be called prior to each time step. Checks are performed by default.
SIM	NAM	OPTIONS	MEMORY_PRINT_OPTION	STRING	is a flag that controls printing of detailed memory manager usage to the end of the simulation list file. NONE means do not print detailed information. SUMMARY means print only the total memory for each simulation component. ALL means print information for each variable stored in the memory manager. NONE is default if MEMORY_PRINT_OPTION is not specified.
SIM	NAM	OPTIONS	MAXERRORS	INTEGER	maximum number of errors that will be stored and printed.
SIM	NAM	OPTIONS	PRINT_INPUT	KEYWORD	keyword to activate printing of simulation input summaries to the simulation list file (mfsim.lst). With this keyword, input summaries will be written for those packages that support newer input data model routines. Not all packages are supported yet by the newer input data model routines.
SIM	NAM	TIMING	TDIS6	STRING	is the name of the Temporal Discretization (TDIS) Input File.
SIM	NAM	MODELS	MTYPE	STRING	is the type of model to add to simulation.
SIM	NAM	MODELS	MFNAME	STRING	is the file name of the model name file.
SIM	NAM	MODELS	MNAME	STRING	is the user-assigned name of the model. The model name cannot exceed 16 characters and must not have blanks within the name. The model name is case insensitive; any lowercase letters are converted and stored as upper case letters.
SIM	NAM	EXCHANGES	EXGTYPE	STRING	is the exchange type.
SIM	NAM	EXCHANGES	EXGFILE	STRING	is the input file for the exchange.
SIM	NAM	EXCHANGES	EXGMNAMEA	STRING	is the name of the first model that is part of this exchange.
SIM	NAM	EXCHANGES	EXGMNAMEB	STRING	is the name of the second model that is part of this exchange.
SIM	NAM	SOLUTIONGROUP	GROUP_NUM	INTEGER	is the group number of the solution group. Solution groups must be numbered sequentially, starting with group number one.
SIM	NAM	SOLUTIONGROUP	MXITER	INTEGER	is the maximum number of outer iterations for this solution group. The default value is 1. If there is only one solution in the solution group, then MXITER must be 1.
SIM	NAM	SOLUTIONGROUP	SLNTYPE	STRING	is the type of solution. The Integrated Model Solution (IMS6) is the only supported option in this version.
SIM	NAM	SOLUTIONGROUP	SLNFNAME	STRING	name of file containing solution input.
SIM	NAM	SOLUTIONGROUP	SLNMNAMES	STRING (:)	is the array of model names to add to this solution. The number of model names is determined by the number of model names the user provides on this line.
SIM	TDIS	OPTIONS	TIME_UNITS	STRING	is the time units of the simulation. This is a text string that is used as a label within model output files. Values for time_units may be unknown'', seconds'', minutes'', hours'', days'', or years''. The default time unit is ``unknown''.
SIM	TDIS	OPTIONS	START_DATE_TIME	STRING	is the starting date and time of the simulation. This is a text string that is used as a label within the simulation list file. The value has no effect on the simulation. The recommended format for the starting date and time is described at https://www.w3.org/TR/NOTE-datetime.
SIM	TDIS	OPTIONS	ATS6	KEYWORD	keyword to specify that record corresponds to an adaptive time step (ATS) input file. The behavior of ATS and a description of the input file is provided separately.
SIM	TDIS	OPTIONS	FILEIN	KEYWORD	keyword to specify that an input filename is expected next.
SIM	TDIS	OPTIONS	ATS6_FILENAME	STRING	defines an adaptive time step (ATS) input file defining ATS controls. Records in the ATS file can be used to override the time step behavior for selected stress periods.
SIM	TDIS	DIMENSIONS	NPER	INTEGER	is the number of stress periods for the simulation.
SIM	TDIS	PERIODDATA	PERLEN	DOUBLE PRECISION	is the length of a stress period.
SIM	TDIS	PERIODDATA	NSTP	INTEGER	is the number of time steps in a stress period.
SIM	TDIS	PERIODDATA	TSMULT	DOUBLE PRECISION	is the multiplier for the length of successive time steps. The length of a time step is calculated by multiplying the length of the previous time step by TSMULT. The length of the first time step, $\Delta t_1$, is related to PERLEN, NSTP, and TSMULT by the relation $\Delta t_1= perlen \frac{tsmult - 1}{tsmult^{nstp}-1}$.
EXG	GWFGWF	OPTIONS	AUXILIARY	STRING (NAUX)	an array of auxiliary variable names. There is no limit on the number of auxiliary variables that can be provided. Most auxiliary variables will not be used by the GWF-GWF Exchange, but they will be available for use by other parts of the program. If an auxiliary variable with the name ANGLDEGX'' is found, then this information will be used as the angle (provided in degrees) between the connection face normal and the x axis, where a value of zero indicates that a normal vector points directly along the positive x axis. The connection face normal is a normal vector on the cell face shared between the cell in model 1 and the cell in model 2 pointing away from the model 1 cell. Additional information on ANGLDEGX'' is provided in the description of the DISU Package. If an auxiliary variable with the name ``CDIST'' is found, then this information will be used as the straight-line connection distance, including the vertical component, between the two cell centers. Both ANGLDEGX and CDIST are required if specific discharge is calculated for either of the groundwater models.
EXG	GWFGWF	OPTIONS	BOUNDNAMES	KEYWORD	keyword to indicate that boundary names may be provided with the list of GWF Exchange cells.
EXG	GWFGWF	OPTIONS	PRINT_INPUT	KEYWORD	keyword to indicate that the list of exchange entries will be echoed to the listing file immediately after it is read.
EXG	GWFGWF	OPTIONS	PRINT_FLOWS	KEYWORD	keyword to indicate that the list of exchange flow rates will be printed to the listing file for every stress period in which ``SAVE BUDGET'' is specified in Output Control.
EXG	GWFGWF	OPTIONS	SAVE_FLOWS	KEYWORD	keyword to indicate that cell-by-cell flow terms will be written to the budget file for each model provided that the Output Control for the models are set up with the ``BUDGET SAVE FILE'' option.
EXG	GWFGWF	OPTIONS	CELL_AVERAGING	STRING	is a keyword and text keyword to indicate the method that will be used for calculating the conductance for horizontal cell connections. The text value for CELL_AVERAGING can be HARMONIC'', LOGARITHMIC'', or AMT-LMK'', which means arithmetic-mean thickness and logarithmic-mean hydraulic conductivity''. If the user does not specify a value for CELL_AVERAGING, then the harmonic-mean method will be used.
EXG	GWFGWF	OPTIONS	VARIABLECV	KEYWORD	keyword to indicate that the vertical conductance will be calculated using the saturated thickness and properties of the overlying cell and the thickness and properties of the underlying cell. If the DEWATERED keyword is also specified, then the vertical conductance is calculated using only the saturated thickness and properties of the overlying cell if the head in the underlying cell is below its top. If these keywords are not specified, then the default condition is to calculate the vertical conductance at the start of the simulation using the initial head and the cell properties. The vertical conductance remains constant for the entire simulation.
EXG	GWFGWF	OPTIONS	DEWATERED	KEYWORD	If the DEWATERED keyword is specified, then the vertical conductance is calculated using only the saturated thickness and properties of the overlying cell if the head in the underlying cell is below its top.
EXG	GWFGWF	OPTIONS	NEWTON	KEYWORD	keyword that activates the Newton-Raphson formulation for groundwater flow between connected, convertible groundwater cells. Cells will not dry when this option is used.
EXG	GWFGWF	OPTIONS	XT3D	KEYWORD	keyword that activates the XT3D formulation between the cells connected with this GWF-GWF Exchange.
EXG	GWFGWF	OPTIONS	FILEIN	KEYWORD	keyword to specify that an input filename is expected next.
EXG	GWFGWF	OPTIONS	GNC6	KEYWORD	keyword to specify that record corresponds to a ghost-node correction file.
EXG	GWFGWF	OPTIONS	GNC6_FILENAME	STRING	is the file name for ghost node correction input file. Information for the ghost nodes are provided in the file provided with these keywords. The format for specifying the ghost nodes is the same as described for the GNC Package of the GWF Model. This includes specifying OPTIONS, DIMENSIONS, and GNCDATA blocks. The order of the ghost nodes must follow the same order as the order of the cells in the EXCHANGEDATA block. For the GNCDATA, noden and all of the nodej values are assumed to be located in model 1, and nodem is assumed to be in model 2.
EXG	GWFGWF	OPTIONS	MVR6	KEYWORD	keyword to specify that record corresponds to a mover file.
EXG	GWFGWF	OPTIONS	MVR6_FILENAME	STRING	is the file name of the water mover input file to apply to this exchange. Information for the water mover are provided in the file provided with these keywords. The format for specifying the water mover information is the same as described for the Water Mover (MVR) Package of the GWF Model, with two exceptions. First, in the PACKAGES block, the model name must be included as a separate string before each package. Second, the appropriate model name must be included before package name 1 and package name 2 in the BEGIN PERIOD block. This allows providers and receivers to be located in both models listed as part of this exchange.
EXG	GWFGWF	OPTIONS	OBS6	KEYWORD	keyword to specify that record corresponds to an observations file.
EXG	GWFGWF	OPTIONS	OBS6_FILENAME	STRING	is the file name of the observations input file for this exchange. See the ``Observation utility'' section for instructions for preparing observation input files. Table \ref{table:gwf-obstypetable} lists observation type(s) supported by the GWF-GWF package.
EXG	GWFGWF	OPTIONS	DEV_INTERFACEMODEL_ON	KEYWORD	activates the interface model mechanism for calculating the coefficients at (and possibly near) the exchange. This keyword should only be used for development purposes.
EXG	GWFGWF	DIMENSIONS	NEXG	INTEGER	keyword and integer value specifying the number of GWF-GWF exchanges.
EXG	GWFGWF	EXCHANGEDATA	CELLIDM1	INTEGER	is the cellid of the cell in model 1 as specified in the simulation name file. For a structured grid that uses the DIS input file, CELLIDM1 is the layer, row, and column numbers of the cell. For a grid that uses the DISV input file, CELLIDM1 is the layer number and CELL2D number for the two cells. If the model uses the unstructured discretization (DISU) input file, then CELLIDM1 is the node number for the cell.
EXG	GWFGWF	EXCHANGEDATA	CELLIDM2	INTEGER	is the cellid of the cell in model 2 as specified in the simulation name file. For a structured grid that uses the DIS input file, CELLIDM2 is the layer, row, and column numbers of the cell. For a grid that uses the DISV input file, CELLIDM2 is the layer number and CELL2D number for the two cells. If the model uses the unstructured discretization (DISU) input file, then CELLIDM2 is the node number for the cell.
EXG	GWFGWF	EXCHANGEDATA	IHC	INTEGER	is an integer flag indicating the direction between node n and all of its m connections. If IHC = 0 then the connection is vertical. If IHC = 1 then the connection is horizontal. If IHC = 2 then the connection is horizontal for a vertically staggered grid.
EXG	GWFGWF	EXCHANGEDATA	CL1	DOUBLE PRECISION	is the distance between the center of cell 1 and the its shared face with cell 2.
EXG	GWFGWF	EXCHANGEDATA	CL2	DOUBLE PRECISION	is the distance between the center of cell 2 and the its shared face with cell 1.
EXG	GWFGWF	EXCHANGEDATA	HWVA	DOUBLE PRECISION	is the horizontal width of the flow connection between cell 1 and cell 2 if IHC $>$ 0, or it is the area perpendicular to flow of the vertical connection between cell 1 and cell 2 if IHC = 0.
EXG	GWFGWF	EXCHANGEDATA	AUX	DOUBLE PRECISION (NAUX)	represents the values of the auxiliary variables for each GWFGWF Exchange. The values of auxiliary variables must be present for each exchange. The values must be specified in the order of the auxiliary variables specified in the OPTIONS block.
EXG	GWFGWF	EXCHANGEDATA	BOUNDNAME	STRING	name of the GWF Exchange 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.
EXG	GWTGWT	OPTIONS	GWFMODELNAME1	STRING	keyword to specify name of first corresponding GWF Model. In the simulation name file, the GWT6-GWT6 entry contains names for GWT Models (exgmnamea and exgmnameb). The GWT Model with the name exgmnamea must correspond to the GWF Model with the name gwfmodelname1.
EXG	GWTGWT	OPTIONS	GWFMODELNAME2	STRING	keyword to specify name of second corresponding GWF Model. In the simulation name file, the GWT6-GWT6 entry contains names for GWT Models (exgmnamea and exgmnameb). The GWT Model with the name exgmnameb must correspond to the GWF Model with the name gwfmodelname2.
EXG	GWTGWT	OPTIONS	AUXILIARY	STRING (NAUX)	an array of auxiliary variable names. There is no limit on the number of auxiliary variables that can be provided. Most auxiliary variables will not be used by the GWF-GWF Exchange, but they will be available for use by other parts of the program. If an auxiliary variable with the name ANGLDEGX'' is found, then this information will be used as the angle (provided in degrees) between the connection face normal and the x axis, where a value of zero indicates that a normal vector points directly along the positive x axis. The connection face normal is a normal vector on the cell face shared between the cell in model 1 and the cell in model 2 pointing away from the model 1 cell. Additional information on ANGLDEGX'' is provided in the description of the DISU Package. If an auxiliary variable with the name ``CDIST'' is found, then this information will be used as the straight-line connection distance, including the vertical component, between the two cell centers. Both ANGLDEGX and CDIST are required if specific discharge is calculated for either of the groundwater models.
EXG	GWTGWT	OPTIONS	BOUNDNAMES	KEYWORD	keyword to indicate that boundary names may be provided with the list of GWT Exchange cells.
EXG	GWTGWT	OPTIONS	PRINT_INPUT	KEYWORD	keyword to indicate that the list of exchange entries will be echoed to the listing file immediately after it is read.
EXG	GWTGWT	OPTIONS	PRINT_FLOWS	KEYWORD	keyword to indicate that the list of exchange flow rates will be printed to the listing file for every stress period in which ``SAVE BUDGET'' is specified in Output Control.
EXG	GWTGWT	OPTIONS	SAVE_FLOWS	KEYWORD	keyword to indicate that cell-by-cell flow terms will be written to the budget file for each model provided that the Output Control for the models are set up with the ``BUDGET SAVE FILE'' option.
EXG	GWTGWT	OPTIONS	ADV_SCHEME	STRING	scheme used to solve the advection term. Can be upstream, central, or TVD. If not specified, upstream weighting is the default weighting scheme.
EXG	GWTGWT	OPTIONS	DSP_XT3D_OFF	KEYWORD	deactivate the xt3d method for the dispersive flux and use the faster and less accurate approximation for this exchange.
EXG	GWTGWT	OPTIONS	DSP_XT3D_RHS	KEYWORD	add xt3d dispersion terms to right-hand side, when possible, for this exchange.
EXG	GWTGWT	OPTIONS	FILEIN	KEYWORD	keyword to specify that an input filename is expected next.
EXG	GWTGWT	OPTIONS	MVT6	KEYWORD	keyword to specify that record corresponds to a transport mover file.
EXG	GWTGWT	OPTIONS	MVT6_FILENAME	STRING	is the file name of the transport mover input file to apply to this exchange. Information for the transport mover are provided in the file provided with these keywords.
EXG	GWTGWT	OPTIONS	OBS6	KEYWORD	keyword to specify that record corresponds to an observations file.
EXG	GWTGWT	OPTIONS	OBS6_FILENAME	STRING	is the file name of the observations input file for this exchange. See the ``Observation utility'' section for instructions for preparing observation input files. Table \ref{table:gwt-obstypetable} lists observation type(s) supported by the GWT-GWT package.
EXG	GWTGWT	OPTIONS	DEV_INTERFACEMODEL_ON	KEYWORD	activates the interface model mechanism for calculating the coefficients at (and possibly near) the exchange. This keyword should only be used for development purposes.
EXG	GWTGWT	DIMENSIONS	NEXG	INTEGER	keyword and integer value specifying the number of GWT-GWT exchanges.
EXG	GWTGWT	EXCHANGEDATA	CELLIDM1	INTEGER	is the cellid of the cell in model 1 as specified in the simulation name file. For a structured grid that uses the DIS input file, CELLIDM1 is the layer, row, and column numbers of the cell. For a grid that uses the DISV input file, CELLIDM1 is the layer number and CELL2D number for the two cells. If the model uses the unstructured discretization (DISU) input file, then CELLIDM1 is the node number for the cell.
EXG	GWTGWT	EXCHANGEDATA	CELLIDM2	INTEGER	is the cellid of the cell in model 2 as specified in the simulation name file. For a structured grid that uses the DIS input file, CELLIDM2 is the layer, row, and column numbers of the cell. For a grid that uses the DISV input file, CELLIDM2 is the layer number and CELL2D number for the two cells. If the model uses the unstructured discretization (DISU) input file, then CELLIDM2 is the node number for the cell.
EXG	GWTGWT	EXCHANGEDATA	IHC	INTEGER	is an integer flag indicating the direction between node n and all of its m connections. If IHC = 0 then the connection is vertical. If IHC = 1 then the connection is horizontal. If IHC = 2 then the connection is horizontal for a vertically staggered grid.
EXG	GWTGWT	EXCHANGEDATA	CL1	DOUBLE PRECISION	is the distance between the center of cell 1 and the its shared face with cell 2.
EXG	GWTGWT	EXCHANGEDATA	CL2	DOUBLE PRECISION	is the distance between the center of cell 2 and the its shared face with cell 1.
EXG	GWTGWT	EXCHANGEDATA	HWVA	DOUBLE PRECISION	is the horizontal width of the flow connection between cell 1 and cell 2 if IHC $>$ 0, or it is the area perpendicular to flow of the vertical connection between cell 1 and cell 2 if IHC = 0.
EXG	GWTGWT	EXCHANGEDATA	AUX	DOUBLE PRECISION (NAUX)	represents the values of the auxiliary variables for each GWTGWT Exchange. The values of auxiliary variables must be present for each exchange. The values must be specified in the order of the auxiliary variables specified in the OPTIONS block.
EXG	GWTGWT	EXCHANGEDATA	BOUNDNAME	STRING	name of the GWT Exchange 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.
SLN	IMS	OPTIONS	PRINT_OPTION	STRING	is a flag that controls printing of convergence information from the solver. NONE means print nothing. SUMMARY means print only the total number of iterations and nonlinear residual reduction summaries. ALL means print linear matrix solver convergence information to the solution listing file and model specific linear matrix solver convergence information to each model listing file in addition to SUMMARY information. NONE is default if PRINT_OPTION is not specified.
SLN	IMS	OPTIONS	COMPLEXITY	STRING	is an optional keyword that defines default non-linear and linear solver parameters. SIMPLE - indicates that default solver input values will be defined that work well for nearly linear models. This would be used for models that do not include nonlinear stress packages and models that are either confined or consist of a single unconfined layer that is thick enough to contain the water table within a single layer. MODERATE - indicates that default solver input values will be defined that work well for moderately nonlinear models. This would be used for models that include nonlinear stress packages and models that consist of one or more unconfined layers. The MODERATE option should be used when the SIMPLE option does not result in successful convergence. COMPLEX - indicates that default solver input values will be defined that work well for highly nonlinear models. This would be used for models that include nonlinear stress packages and models that consist of one or more unconfined layers representing complex geology and surface-water/groundwater interaction. The COMPLEX option should be used when the MODERATE option does not result in successful convergence. Non-linear and linear solver parameters assigned using a specified complexity can be modified in the NONLINEAR and LINEAR blocks. If the COMPLEXITY option is not specified, NONLINEAR and LINEAR variables will be assigned the simple complexity values.
SLN	IMS	OPTIONS	CSV_OUTPUT	KEYWORD	keyword to specify that the record corresponds to the comma separated values solver convergence output. The CSV_OUTPUT option has been deprecated and split into the CSV_OUTER_OUTPUT and CSV_INNER_OUTPUT options. Starting with MODFLOW 6 version 6.1.1 if the CSV_OUTPUT option is specified, then it is treated as the CSV_OUTER_OUTPUT option.
SLN	IMS	OPTIONS	CSVFILE	STRING	name of the ascii comma separated values output file to write solver convergence information. If PRINT_OPTION is NONE or SUMMARY, comma separated values output includes maximum head change convergence information at the end of each outer iteration for each time step. If PRINT_OPTION is ALL, comma separated values output includes maximum head change and maximum residual convergence information for the solution and each model (if the solution includes more than one model) and linear acceleration information for each inner iteration.
SLN	IMS	OPTIONS	CSV_OUTER_OUTPUT	KEYWORD	keyword to specify that the record corresponds to the comma separated values outer iteration convergence output.
SLN	IMS	OPTIONS	FILEOUT	KEYWORD	keyword to specify that an output filename is expected next.
SLN	IMS	OPTIONS	OUTER_CSVFILE	STRING	name of the ascii comma separated values output file to write maximum dependent-variable (for example, head) change convergence information at the end of each outer iteration for each time step.
SLN	IMS	OPTIONS	CSV_INNER_OUTPUT	KEYWORD	keyword to specify that the record corresponds to the comma separated values solver convergence output.
SLN	IMS	OPTIONS	INNER_CSVFILE	STRING	name of the ascii comma separated values output file to write solver convergence information. Comma separated values output includes maximum dependent-variable (for example, head) change and maximum residual convergence information for the solution and each model (if the solution includes more than one model) and linear acceleration information for each inner iteration.
SLN	IMS	OPTIONS	NO_PTC	KEYWORD	is a flag that is used to disable pseudo-transient continuation (PTC). Option only applies to steady-state stress periods for models using the Newton-Raphson formulation. For many problems, PTC can significantly improve convergence behavior for steady-state simulations, and for this reason it is active by default. In some cases, however, PTC can worsen the convergence behavior, especially when the initial conditions are similar to the solution. When the initial conditions are similar to, or exactly the same as, the solution and convergence is slow, then the NO_PTC FIRST option should be used to deactivate PTC for the first stress period. The NO_PTC ALL option should also be used in order to compare convergence behavior with other MODFLOW versions, as PTC is only available in MODFLOW 6.
SLN	IMS	OPTIONS	NO_PTC_OPTION	STRING	is an optional keyword that is used to define options for disabling pseudo-transient continuation (PTC). FIRST is an optional keyword to disable PTC for the first stress period, if steady-state and one or more model is using the Newton-Raphson formulation. ALL is an optional keyword to disable PTC for all steady-state stress periods for models using the Newton-Raphson formulation. If NO_PTC_OPTION is not specified, the NO_PTC ALL option is used.
SLN	IMS	OPTIONS	ATS_OUTER_MAXIMUM_FRACTION	DOUBLE PRECISION	real value defining the fraction of the maximum allowable outer iterations used with the Adaptive Time Step (ATS) capability if it is active. If this value is set to zero by the user, then this solution will have no effect on ATS behavior. This value must be greater than or equal to zero and less than or equal to 0.5 or the program will terminate with an error. If it is not specified by the user, then it is assigned a default value of one third. When the number of outer iterations for this solution is less than the product of this value and the maximum allowable outer iterations, then ATS will increase the time step length by a factor of DTADJ in the ATS input file. When the number of outer iterations for this solution is greater than the maximum allowable outer iterations minus the product of this value and the maximum allowable outer iterations, then the ATS (if active) will decrease the time step length by a factor of 1 / DTADJ.
SLN	IMS	NONLINEAR	OUTER_HCLOSE	DOUBLE PRECISION	real value defining the head change criterion for convergence of the outer (nonlinear) iterations, in units of length. When the maximum absolute value of the head change at all nodes during an iteration is less than or equal to OUTER_HCLOSE, iteration stops. Commonly, OUTER_HCLOSE equals 0.01. The OUTER_HCLOSE option has been deprecated in favor of the more general OUTER_DVCLOSE (for dependent variable), however either one can be specified in order to maintain backward compatibility.
SLN	IMS	NONLINEAR	OUTER_DVCLOSE	DOUBLE PRECISION	real value defining the dependent-variable (for example, head) change criterion for convergence of the outer (nonlinear) iterations, in units of the dependent-variable (for example, length for head). When the maximum absolute value of the dependent-variable change at all nodes during an iteration is less than or equal to OUTER_DVCLOSE, iteration stops. Commonly, OUTER_DVCLOSE equals 0.01. The keyword, OUTER_HCLOSE can be still be specified instead of OUTER_DVCLOSE for backward compatibility with previous versions of MODFLOW 6 but eventually OUTER_HCLOSE will be deprecated and specification of OUTER_HCLOSE will cause MODFLOW 6 to terminate with an error.
SLN	IMS	NONLINEAR	OUTER_RCLOSEBND	DOUBLE PRECISION	real value defining the residual tolerance for convergence of model packages that solve a separate equation not solved by the IMS linear solver. This value represents the maximum allowable residual between successive outer iterations at any single model package element. An example of a model package that would use OUTER_RCLOSEBND to evaluate convergence is the SFR package which solves a continuity equation for each reach. The OUTER_RCLOSEBND option is deprecated and has no effect on simulation results as of version 6.1.1. The keyword, OUTER_RCLOSEBND can be still be specified for backward compatibility with previous versions of MODFLOW 6 but eventually specificiation of OUTER_RCLOSEBND will cause MODFLOW 6 to terminate with an error.
SLN	IMS	NONLINEAR	OUTER_MAXIMUM	INTEGER	integer value defining the maximum number of outer (nonlinear) iterations -- that is, calls to the solution routine. For a linear problem OUTER_MAXIMUM should be 1.
SLN	IMS	NONLINEAR	UNDER_RELAXATION	STRING	is an optional keyword that defines the nonlinear under-relaxation schemes used. Under-relaxation is also known as dampening, and is used to reduce the size of the calculated dependent variable before proceeding to the next outer iteration. Under-relaxation can be an effective tool for highly nonlinear models when there are large and often counteracting changes in the calculated dependent variable between successive outer iterations. By default under-relaxation is not used. NONE - under-relaxation is not used (default). SIMPLE - Simple under-relaxation scheme with a fixed relaxation factor (UNDER_RELAXATION_GAMMA) is used. COOLEY - Cooley under-relaxation scheme is used. DBD - delta-bar-delta under-relaxation is used. Note that the under-relaxation schemes are often used in conjunction with problems that use the Newton-Raphson formulation, however, experience has indicated that they also work well for non-Newton problems, such as those with the wet/dry options of MODFLOW 6.
SLN	IMS	NONLINEAR	UNDER_RELAXATION_GAMMA	DOUBLE PRECISION	real value defining either the relaxation factor for the SIMPLE scheme or the history or memory term factor of the Cooley and delta-bar-delta algorithms. For the SIMPLE scheme, a value of one indicates that there is no under-relaxation and the full head change is applied. This value can be gradually reduced from one as a way to improve convergence; for well behaved problems, using a value less than one can increase the number of outer iterations required for convergence and needlessly increase run times. UNDER_RELAXATION_GAMMA must be greater than zero for the SIMPLE scheme or the program will terminate with an error. For the Cooley and delta-bar-delta schemes, UNDER_RELAXATION_GAMMA is a memory term that can range between zero and one. When UNDER_RELAXATION_GAMMA is zero, only the most recent history (previous iteration value) is maintained. As UNDER_RELAXATION_GAMMA is increased, past history of iteration changes has greater influence on the memory term. The memory term is maintained as an exponential average of past changes. Retaining some past history can overcome granular behavior in the calculated function surface and therefore helps to overcome cyclic patterns of non-convergence. The value usually ranges from 0.1 to 0.3; a value of 0.2 works well for most problems. UNDER_RELAXATION_GAMMA only needs to be specified if UNDER_RELAXATION is not NONE.
SLN	IMS	NONLINEAR	UNDER_RELAXATION_THETA	DOUBLE PRECISION	real value defining the reduction factor for the learning rate (under-relaxation term) of the delta-bar-delta algorithm. The value of UNDER_RELAXATION_THETA is between zero and one. If the change in the dependent-variable (for example, head) is of opposite sign to that of the previous iteration, the under-relaxation term is reduced by a factor of UNDER_RELAXATION_THETA. The value usually ranges from 0.3 to 0.9; a value of 0.7 works well for most problems. UNDER_RELAXATION_THETA only needs to be specified if UNDER_RELAXATION is DBD.
SLN	IMS	NONLINEAR	UNDER_RELAXATION_KAPPA	DOUBLE PRECISION	real value defining the increment for the learning rate (under-relaxation term) of the delta-bar-delta algorithm. The value of UNDER_RELAXATION_kappa is between zero and one. If the change in the dependent-variable (for example, head) is of the same sign to that of the previous iteration, the under-relaxation term is increased by an increment of UNDER_RELAXATION_KAPPA. The value usually ranges from 0.03 to 0.3; a value of 0.1 works well for most problems. UNDER_RELAXATION_KAPPA only needs to be specified if UNDER_RELAXATION is DBD.
SLN	IMS	NONLINEAR	UNDER_RELAXATION_MOMENTUM	DOUBLE PRECISION	real value defining the fraction of past history changes that is added as a momentum term to the step change for a nonlinear iteration. The value of UNDER_RELAXATION_MOMENTUM is between zero and one. A large momentum term should only be used when small learning rates are expected. Small amounts of the momentum term help convergence. The value usually ranges from 0.0001 to 0.1; a value of 0.001 works well for most problems. UNDER_RELAXATION_MOMENTUM only needs to be specified if UNDER_RELAXATION is DBD.
SLN	IMS	NONLINEAR	BACKTRACKING_NUMBER	INTEGER	integer value defining the maximum number of backtracking iterations allowed for residual reduction computations. If BACKTRACKING_NUMBER = 0 then the backtracking iterations are omitted. The value usually ranges from 2 to 20; a value of 10 works well for most problems.
SLN	IMS	NONLINEAR	BACKTRACKING_TOLERANCE	DOUBLE PRECISION	real value defining the tolerance for residual change that is allowed for residual reduction computations. BACKTRACKING_TOLERANCE should not be less than one to avoid getting stuck in local minima. A large value serves to check for extreme residual increases, while a low value serves to control step size more severely. The value usually ranges from 1.0 to 10$^6$; a value of 10$^4$ works well for most problems but lower values like 1.1 may be required for harder problems. BACKTRACKING_TOLERANCE only needs to be specified if BACKTRACKING_NUMBER is greater than zero.
SLN	IMS	NONLINEAR	BACKTRACKING_REDUCTION_FACTOR	DOUBLE PRECISION	real value defining the reduction in step size used for residual reduction computations. The value of BACKTRACKING_REDUCTION_FACTOR is between zero and one. The value usually ranges from 0.1 to 0.3; a value of 0.2 works well for most problems. BACKTRACKING_REDUCTION_FACTOR only needs to be specified if BACKTRACKING_NUMBER is greater than zero.
SLN	IMS	NONLINEAR	BACKTRACKING_RESIDUAL_LIMIT	DOUBLE PRECISION	real value defining the limit to which the residual is reduced with backtracking. If the residual is smaller than BACKTRACKING_RESIDUAL_LIMIT, then further backtracking is not performed. A value of 100 is suitable for large problems and residual reduction to smaller values may only slow down computations. BACKTRACKING_RESIDUAL_LIMIT only needs to be specified if BACKTRACKING_NUMBER is greater than zero.
SLN	IMS	LINEAR	INNER_MAXIMUM	INTEGER	integer value defining the maximum number of inner (linear) iterations. The number typically depends on the characteristics of the matrix solution scheme being used. For nonlinear problems, INNER_MAXIMUM usually ranges from 60 to 600; a value of 100 will be sufficient for most linear problems.
SLN	IMS	LINEAR	INNER_HCLOSE	DOUBLE PRECISION	real value defining the head change criterion for convergence of the inner (linear) iterations, in units of length. When the maximum absolute value of the head change at all nodes during an iteration is less than or equal to INNER_HCLOSE, the matrix solver assumes convergence. Commonly, INNER_HCLOSE is set equal to or an order of magnitude less than the OUTER_HCLOSE value specified for the NONLINEAR block. The INNER_HCLOSE keyword has been deprecated in favor of the more general INNER_DVCLOSE (for dependent variable), however either one can be specified in order to maintain backward compatibility.
SLN	IMS	LINEAR	INNER_DVCLOSE	DOUBLE PRECISION	real value defining the dependent-variable (for example, head) change criterion for convergence of the inner (linear) iterations, in units of the dependent-variable (for example, length for head). When the maximum absolute value of the dependent-variable change at all nodes during an iteration is less than or equal to INNER_DVCLOSE, the matrix solver assumes convergence. Commonly, INNER_DVCLOSE is set equal to or an order of magnitude less than the OUTER_DVCLOSE value specified for the NONLINEAR block. The keyword, INNER_HCLOSE can be still be specified instead of INNER_DVCLOSE for backward compatibility with previous versions of MODFLOW 6 but eventually INNER_HCLOSE will be deprecated and specification of INNER_HCLOSE will cause MODFLOW 6 to terminate with an error.
SLN	IMS	LINEAR	INNER_RCLOSE	DOUBLE PRECISION	real value that defines the flow residual tolerance for convergence of the IMS linear solver and specific flow residual criteria used. This value represents the maximum allowable residual at any single node. Value is in units of length cubed per time, and must be consistent with \mf length and time units. Usually a value of $1.0 \times 10^{-1}$ is sufficient for the flow-residual criteria when meters and seconds are the defined \mf length and time.
SLN	IMS	LINEAR	RCLOSE_OPTION	STRING	an optional keyword that defines the specific flow residual criterion used. STRICT--an optional keyword that is used to specify that INNER_RCLOSE represents a infinity-Norm (absolute convergence criteria) and that the dependent-variable (for example, head) and flow convergence criteria must be met on the first inner iteration (this criteria is equivalent to the criteria used by the MODFLOW-2005 PCG package~\citep{hill1990preconditioned}). L2NORM_RCLOSE--an optional keyword that is used to specify that INNER_RCLOSE represents a L-2 Norm closure criteria instead of a infinity-Norm (absolute convergence criteria). When L2NORM_RCLOSE is specified, a reasonable initial INNER_RCLOSE value is 0.1 times the number of active cells when meters and seconds are the defined \mf length and time. RELATIVE_RCLOSE--an optional keyword that is used to specify that INNER_RCLOSE represents a relative L-2 Norm reduction closure criteria instead of a infinity-Norm (absolute convergence criteria). When RELATIVE_RCLOSE is specified, a reasonable initial INNER_RCLOSE value is $1.0 \times 10^{-4}$ and convergence is achieved for a given inner (linear) iteration when $\Delta h \le$ INNER_DVCLOSE and the current L-2 Norm is $\le$ the product of the RELATIVE_RCLOSE and the initial L-2 Norm for the current inner (linear) iteration. If RCLOSE_OPTION is not specified, an absolute residual (infinity-norm) criterion is used.
SLN	IMS	LINEAR	LINEAR_ACCELERATION	STRING	a keyword that defines the linear acceleration method used by the default IMS linear solvers. CG - preconditioned conjugate gradient method. BICGSTAB - preconditioned bi-conjugate gradient stabilized method.
SLN	IMS	LINEAR	RELAXATION_FACTOR	DOUBLE PRECISION	optional real value that defines the relaxation factor used by the incomplete LU factorization preconditioners (MILU(0) and MILUT). RELAXATION_FACTOR is unitless and should be greater than or equal to 0.0 and less than or equal to 1.0. RELAXATION_FACTOR values of about 1.0 are commonly used, and experience suggests that convergence can be optimized in some cases with relax values of 0.97. A RELAXATION_FACTOR value of 0.0 will result in either ILU(0) or ILUT preconditioning (depending on the value specified for PRECONDITIONER_LEVELS and/or PRECONDITIONER_DROP_TOLERANCE). By default, RELAXATION_FACTOR is zero.
SLN	IMS	LINEAR	PRECONDITIONER_LEVELS	INTEGER	optional integer value defining the level of fill for ILU decomposition used in the ILUT and MILUT preconditioners. Higher levels of fill provide more robustness but also require more memory. For optimal performance, it is suggested that a large level of fill be applied (7 or 8) with use of a drop tolerance. Specification of a PRECONDITIONER_LEVELS value greater than zero results in use of the ILUT preconditioner. By default, PRECONDITIONER_LEVELS is zero and the zero-fill incomplete LU factorization preconditioners (ILU(0) and MILU(0)) are used.
SLN	IMS	LINEAR	PRECONDITIONER_DROP_TOLERANCE	DOUBLE PRECISION	optional real value that defines the drop tolerance used to drop preconditioner terms based on the magnitude of matrix entries in the ILUT and MILUT preconditioners. A value of $10^{-4}$ works well for most problems. By default, PRECONDITIONER_DROP_TOLERANCE is zero and the zero-fill incomplete LU factorization preconditioners (ILU(0) and MILU(0)) are used.
SLN	IMS	LINEAR	NUMBER_ORTHOGONALIZATIONS	INTEGER	optional integer value defining the interval used to explicitly recalculate the residual of the flow equation using the solver coefficient matrix, the latest dependent-variable (for example, head) estimates, and the right hand side. For problems that benefit from explicit recalculation of the residual, a number between 4 and 10 is appropriate. By default, NUMBER_ORTHOGONALIZATIONS is zero.
SLN	IMS	LINEAR	SCALING_METHOD	STRING	an optional keyword that defines the matrix scaling approach used. By default, matrix scaling is not applied. NONE - no matrix scaling applied. DIAGONAL - symmetric matrix scaling using the POLCG preconditioner scaling method in Hill (1992). L2NORM - symmetric matrix scaling using the L2 norm.
SLN	IMS	LINEAR	REORDERING_METHOD	STRING	an optional keyword that defines the matrix reordering approach used. By default, matrix reordering is not applied. NONE - original ordering. RCM - reverse Cuthill McKee ordering. MD - minimum degree ordering.
GWF	NAM	OPTIONS	LIST	STRING	is name of the listing file to create for this GWF model. If not specified, then the name of the list file will be the basename of the GWF model name file and the '.lst' extension. For example, if the GWF name file is called my.model.nam'' then the list file will be called my.model.lst''.
GWF	NAM	OPTIONS	PRINT_INPUT	KEYWORD	keyword to indicate that the list of all model stress package information will be written to the listing file immediately after it is read.
GWF	NAM	OPTIONS	PRINT_FLOWS	KEYWORD	keyword to indicate that the list of all model package 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.
GWF	NAM	OPTIONS	SAVE_FLOWS	KEYWORD	keyword to indicate that all model package flow terms will be written to the file specified with ``BUDGET FILEOUT'' in Output Control.
GWF	NAM	OPTIONS	NEWTON	KEYWORD	keyword that activates the Newton-Raphson formulation for groundwater flow between connected, convertible groundwater cells and stress packages that support calculation of Newton-Raphson terms for groundwater exchanges. Cells will not dry when this option is used. By default, the Newton-Raphson formulation is not applied.
GWF	NAM	OPTIONS	UNDER_RELAXATION	KEYWORD	keyword that indicates whether the groundwater head in a cell will be under-relaxed when water levels fall below the bottom of the model below any given cell. By default, Newton-Raphson UNDER_RELAXATION is not applied.
GWF	NAM	PACKAGES	FTYPE	STRING	is the file type, which must be one of the following character values shown in table~\ref{table:ftype}. Ftype may be entered in any combination of uppercase and lowercase.
GWF	NAM	PACKAGES	FNAME	STRING	is the name of the file containing the package input. The path to the file should be included if the file is not located in the folder where the program was run.
GWF	NAM	PACKAGES	PNAME	STRING	is the user-defined name for the package. PNAME is restricted to 16 characters. No spaces are allowed in PNAME. PNAME character values are read and stored by the program for stress packages only. These names may be useful for labeling purposes when multiple stress packages of the same type are located within a single GWF Model. If PNAME is specified for a stress package, then PNAME will be used in the flow budget table in the listing file; it will also be used for the text entry in the cell-by-cell budget file. PNAME is case insensitive and is stored in all upper case letters.
GWF	DIS	OPTIONS	LENGTH_UNITS	STRING	is the length units used for this model. Values can be FEET'', METERS'', or CENTIMETERS''. If not specified, the default is UNKNOWN''.
GWF	DIS	OPTIONS	NOGRB	KEYWORD	keyword to deactivate writing of the binary grid file.
GWF	DIS	OPTIONS	XORIGIN	DOUBLE PRECISION	x-position of the lower-left corner of the model grid. A default value of zero is assigned if not specified. The value for XORIGIN does not affect the model simulation, but it is written to the binary grid file so that postprocessors can locate the grid in space.
GWF	DIS	OPTIONS	YORIGIN	DOUBLE PRECISION	y-position of the lower-left corner of the model grid. If not specified, then a default value equal to zero is used. The value for YORIGIN does not affect the model simulation, but it is written to the binary grid file so that postprocessors can locate the grid in space.
GWF	DIS	OPTIONS	ANGROT	DOUBLE PRECISION	counter-clockwise rotation angle (in degrees) of the lower-left corner of the model grid. If not specified, then a default value of 0.0 is assigned. The value for ANGROT does not affect the model simulation, but it is written to the binary grid file so that postprocessors can locate the grid in space.
GWF	DIS	DIMENSIONS	NLAY	INTEGER	is the number of layers in the model grid.
GWF	DIS	DIMENSIONS	NROW	INTEGER	is the number of rows in the model grid.
GWF	DIS	DIMENSIONS	NCOL	INTEGER	is the number of columns in the model grid.
GWF	DIS	GRIDDATA	DELR	DOUBLE PRECISION (NCOL)	is the column spacing in the row direction.
GWF	DIS	GRIDDATA	DELC	DOUBLE PRECISION (NROW)	is the row spacing in the column direction.
GWF	DIS	GRIDDATA	TOP	DOUBLE PRECISION (NCOL, NROW)	is the top elevation for each cell in the top model layer.
GWF	DIS	GRIDDATA	BOTM	DOUBLE PRECISION (NCOL, NROW, NLAY)	is the bottom elevation for each cell.
GWF	DIS	GRIDDATA	IDOMAIN	INTEGER (NCOL, NROW, NLAY)	is an optional array that characterizes the existence status of a cell. If the IDOMAIN array is not specified, then all model cells exist within the solution. If the IDOMAIN value for a cell is 0, the cell does not exist in the simulation. Input and output values will be read and written for the cell, but internal to the program, the cell is excluded from the solution. If the IDOMAIN value for a cell is 1 or greater, the cell exists in the simulation. If the IDOMAIN value for a cell is -1, the cell does not exist in the simulation. Furthermore, the first existing cell above will be connected to the first existing cell below. This type of cell is referred to as a ``vertical pass through'' cell.
GWF	DISV	OPTIONS	LENGTH_UNITS	STRING	is the length units used for this model. Values can be FEET'', METERS'', or CENTIMETERS''. If not specified, the default is UNKNOWN''.
GWF	DISV	OPTIONS	NOGRB	KEYWORD	keyword to deactivate writing of the binary grid file.
GWF	DISV	OPTIONS	XORIGIN	DOUBLE PRECISION	x-position of the origin used for model grid vertices. This value should be provided in a real-world coordinate system. A default value of zero is assigned if not specified. The value for XORIGIN does not affect the model simulation, but it is written to the binary grid file so that postprocessors can locate the grid in space.
GWF	DISV	OPTIONS	YORIGIN	DOUBLE PRECISION	y-position of the origin used for model grid vertices. This value should be provided in a real-world coordinate system. If not specified, then a default value equal to zero is used. The value for YORIGIN does not affect the model simulation, but it is written to the binary grid file so that postprocessors can locate the grid in space.
GWF	DISV	OPTIONS	ANGROT	DOUBLE PRECISION	counter-clockwise rotation angle (in degrees) of the model grid coordinate system relative to a real-world coordinate system. If not specified, then a default value of 0.0 is assigned. The value for ANGROT does not affect the model simulation, but it is written to the binary grid file so that postprocessors can locate the grid in space.
GWF	DISV	DIMENSIONS	NLAY	INTEGER	is the number of layers in the model grid.
GWF	DISV	DIMENSIONS	NCPL	INTEGER	is the number of cells per layer. This is a constant value for the grid and it applies to all layers.
GWF	DISV	DIMENSIONS	NVERT	INTEGER	is the total number of (x, y) vertex pairs used to characterize the horizontal configuration of the model grid.
GWF	DISV	GRIDDATA	TOP	DOUBLE PRECISION (NCPL)	is the top elevation for each cell in the top model layer.
GWF	DISV	GRIDDATA	BOTM	DOUBLE PRECISION (NCPL, NLAY)	is the bottom elevation for each cell.
GWF	DISV	GRIDDATA	IDOMAIN	INTEGER (NCPL, NLAY)	is an optional array that characterizes the existence status of a cell. If the IDOMAIN array is not specified, then all model cells exist within the solution. If the IDOMAIN value for a cell is 0, the cell does not exist in the simulation. Input and output values will be read and written for the cell, but internal to the program, the cell is excluded from the solution. If the IDOMAIN value for a cell is 1 or greater, the cell exists in the simulation. If the IDOMAIN value for a cell is -1, the cell does not exist in the simulation. Furthermore, the first existing cell above will be connected to the first existing cell below. This type of cell is referred to as a ``vertical pass through'' cell.
GWF	DISV	VERTICES	IV	INTEGER	is the vertex number. Records in the VERTICES block must be listed in consecutive order from 1 to NVERT.
GWF	DISV	VERTICES	XV	DOUBLE PRECISION	is the x-coordinate for the vertex.
GWF	DISV	VERTICES	YV	DOUBLE PRECISION	is the y-coordinate for the vertex.
GWF	DISV	CELL2D	ICELL2D	INTEGER	is the CELL2D number. Records in the CELL2D block must be listed in consecutive order from the first to the last.
GWF	DISV	CELL2D	XC	DOUBLE PRECISION	is the x-coordinate for the cell center.
GWF	DISV	CELL2D	YC	DOUBLE PRECISION	is the y-coordinate for the cell center.
GWF	DISV	CELL2D	NCVERT	INTEGER	is the number of vertices required to define the cell. There may be a different number of vertices for each cell.
GWF	DISV	CELL2D	ICVERT	INTEGER (NCVERT)	is an array of integer values containing vertex numbers (in the VERTICES block) used to define the cell. Vertices must be listed in clockwise order. Cells that are connected must share vertices.
GWF	DISU	OPTIONS	LENGTH_UNITS	STRING	is the length units used for this model. Values can be FEET'', METERS'', or CENTIMETERS''. If not specified, the default is UNKNOWN''.
GWF	DISU	OPTIONS	NOGRB	KEYWORD	keyword to deactivate writing of the binary grid file.
GWF	DISU	OPTIONS	XORIGIN	DOUBLE PRECISION	x-position of the origin used for model grid vertices. This value should be provided in a real-world coordinate system. A default value of zero is assigned if not specified. The value for XORIGIN does not affect the model simulation, but it is written to the binary grid file so that postprocessors can locate the grid in space.
GWF	DISU	OPTIONS	YORIGIN	DOUBLE PRECISION	y-position of the origin used for model grid vertices. This value should be provided in a real-world coordinate system. If not specified, then a default value equal to zero is used. The value for YORIGIN does not affect the model simulation, but it is written to the binary grid file so that postprocessors can locate the grid in space.
GWF	DISU	OPTIONS	ANGROT	DOUBLE PRECISION	counter-clockwise rotation angle (in degrees) of the model grid coordinate system relative to a real-world coordinate system. If not specified, then a default value of 0.0 is assigned. The value for ANGROT does not affect the model simulation, but it is written to the binary grid file so that postprocessors can locate the grid in space.
GWF	DISU	OPTIONS	VERTICAL_OFFSET_TOLERANCE	DOUBLE PRECISION	checks are performed to ensure that the top of a cell is not higher than the bottom of an overlying cell. This option can be used to specify the tolerance that is used for checking. If top of a cell is above the bottom of an overlying cell by a value less than this tolerance, then the program will not terminate with an error. The default value is zero. This option should generally not be used.
GWF	DISU	DIMENSIONS	NODES	INTEGER	is the number of cells in the model grid.
GWF	DISU	DIMENSIONS	NJA	INTEGER	is the sum of the number of connections and NODES. When calculating the total number of connections, the connection between cell n and cell m is considered to be different from the connection between cell m and cell n. Thus, NJA is equal to the total number of connections, including n to m and m to n, and the total number of cells.
GWF	DISU	DIMENSIONS	NVERT	INTEGER	is the total number of (x, y) vertex pairs used to define the plan-view shape of each cell in the model grid. If NVERT is not specified or is specified as zero, then the VERTICES and CELL2D blocks below are not read. NVERT and the accompanying VERTICES and CELL2D blocks should be specified for most simulations. If the XT3D or SAVE_SPECIFIC_DISCHARGE options are specified in the NPF Package, then this information is required.
GWF	DISU	GRIDDATA	TOP	DOUBLE PRECISION (NODES)	is the top elevation for each cell in the model grid.
GWF	DISU	GRIDDATA	BOT	DOUBLE PRECISION (NODES)	is the bottom elevation for each cell.
GWF	DISU	GRIDDATA	AREA	DOUBLE PRECISION (NODES)	is the cell surface area (in plan view).
GWF	DISU	GRIDDATA	IDOMAIN	INTEGER (NODES)	is an optional array that characterizes the existence status of a cell. If the IDOMAIN array is not specified, then all model cells exist within the solution. If the IDOMAIN value for a cell is 0, the cell does not exist in the simulation. Input and output values will be read and written for the cell, but internal to the program, the cell is excluded from the solution. If the IDOMAIN value for a cell is 1 or greater, the cell exists in the simulation. IDOMAIN values of -1 cannot be specified for the DISU Package.
GWF	DISU	CONNECTIONDATA	IAC	INTEGER (NODES)	is the number of connections (plus 1) for each cell. The sum of all the entries in IAC must be equal to NJA.
GWF	DISU	CONNECTIONDATA	JA	INTEGER (NJA)	is a list of cell number (n) followed by its connecting cell numbers (m) for each of the m cells connected to cell n. The number of values to provide for cell n is IAC(n). This list is sequentially provided for the first to the last cell. The first value in the list must be cell n itself, and the remaining cells must be listed in an increasing order (sorted from lowest number to highest). Note that the cell and its connections are only supplied for the GWF cells and their connections to the other GWF cells. Also note that the JA list input may be divided such that every node and its connectivity list can be on a separate line for ease in readability of the file. To further ease readability of the file, the node number of the cell whose connectivity is subsequently listed, may be expressed as a negative number, the sign of which is subsequently converted to positive by the code.
GWF	DISU	CONNECTIONDATA	IHC	INTEGER (NJA)	is an index array indicating the direction between node n and all of its m connections. If IHC = 0 then cell n and cell m are connected in the vertical direction. Cell n overlies cell m if the cell number for n is less than m; cell m overlies cell n if the cell number for m is less than n. If IHC = 1 then cell n and cell m are connected in the horizontal direction. If IHC = 2 then cell n and cell m are connected in the horizontal direction, and the connection is vertically staggered. A vertically staggered connection is one in which a cell is horizontally connected to more than one cell in a horizontal connection.
GWF	DISU	CONNECTIONDATA	CL12	DOUBLE PRECISION (NJA)	is the array containing connection lengths between the center of cell n and the shared face with each adjacent m cell.
GWF	DISU	CONNECTIONDATA	HWVA	DOUBLE PRECISION (NJA)	is a symmetric array of size NJA. For horizontal connections, entries in HWVA are the horizontal width perpendicular to flow. For vertical connections, entries in HWVA are the vertical area for flow. Thus, values in the HWVA array contain dimensions of both length and area. Entries in the HWVA array have a one-to-one correspondence with the connections specified in the JA array. Likewise, there is a one-to-one correspondence between entries in the HWVA array and entries in the IHC array, which specifies the connection type (horizontal or vertical). Entries in the HWVA array must be symmetric; the program will terminate with an error if the value for HWVA for an n to m connection does not equal the value for HWVA for the corresponding n to m connection.
GWF	DISU	CONNECTIONDATA	ANGLDEGX	DOUBLE PRECISION (NJA)	is the angle (in degrees) between the horizontal x-axis and the outward normal to the face between a cell and its connecting cells. The angle varies between zero and 360.0 degrees, where zero degrees points in the positive x-axis direction, and 90 degrees points in the positive y-axis direction. ANGLDEGX is only needed if horizontal anisotropy is specified in the NPF Package, if the XT3D option is used in the NPF Package, or if the SAVE_SPECIFIC_DISCHARGE option is specifed in the NPF Package. ANGLDEGX does not need to be specified if these conditions are not met. ANGLDEGX is of size NJA; values specified for vertical connections and for the diagonal position are not used. Note that ANGLDEGX is read in degrees, which is different from MODFLOW-USG, which reads a similar variable (ANGLEX) in radians.
GWF	DISU	VERTICES	IV	INTEGER	is the vertex number. Records in the VERTICES block must be listed in consecutive order from 1 to NVERT.
GWF	DISU	VERTICES	XV	DOUBLE PRECISION	is the x-coordinate for the vertex.
GWF	DISU	VERTICES	YV	DOUBLE PRECISION	is the y-coordinate for the vertex.
GWF	DISU	CELL2D	ICELL2D	INTEGER	is the cell2d number. Records in the CELL2D block must be listed in consecutive order from 1 to NODES.
GWF	DISU	CELL2D	XC	DOUBLE PRECISION	is the x-coordinate for the cell center.
GWF	DISU	CELL2D	YC	DOUBLE PRECISION	is the y-coordinate for the cell center.
GWF	DISU	CELL2D	NCVERT	INTEGER	is the number of vertices required to define the cell. There may be a different number of vertices for each cell.
GWF	DISU	CELL2D	ICVERT	INTEGER (NCVERT)	is an array of integer values containing vertex numbers (in the VERTICES block) used to define the cell. Vertices must be listed in clockwise order.
GWF	IC	GRIDDATA	STRT	DOUBLE PRECISION (NODES)	is the initial (starting) head---that is, head at the beginning of the GWF Model simulation. STRT must be specified for all simulations, including steady-state simulations. One value is read for every model cell. For simulations in which the first stress period is steady state, the values used for STRT generally do not affect the simulation (exceptions may occur if cells go dry and (or) rewet). The execution time, however, will be less if STRT includes hydraulic heads that are close to the steady-state solution. A head value lower than the cell bottom can be provided if a cell should start as dry.
GWF	NPF	OPTIONS	SAVE_FLOWS	KEYWORD	keyword to indicate that budget flow terms will be written to the file specified with ``BUDGET SAVE FILE'' in Output Control.
GWF	NPF	OPTIONS	PRINT_FLOWS	KEYWORD	keyword to indicate that calculated flows between cells 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. This option can produce extremely large list files because all cell-by-cell flows are printed. It should only be used with the NPF Package for models that have a small number of cells.
GWF	NPF	OPTIONS	ALTERNATIVE_CELL_AVERAGING	STRING	is a text keyword to indicate that an alternative method will be used for calculating the conductance for horizontal cell connections. The text value for ALTERNATIVE_CELL_AVERAGING can be LOGARITHMIC'', AMT-LMK'', or AMT-HMK''. AMT-LMK'' signifies that the conductance will be calculated using arithmetic-mean thickness and logarithmic-mean hydraulic conductivity. ``AMT-HMK'' signifies that the conductance will be calculated using arithmetic-mean thickness and harmonic-mean hydraulic conductivity. If the user does not specify a value for ALTERNATIVE_CELL_AVERAGING, then the harmonic-mean method will be used. This option cannot be used if the XT3D option is invoked.
GWF	NPF	OPTIONS	THICKSTRT	KEYWORD	indicates that cells having a negative ICELLTYPE are confined, and their cell thickness for conductance calculations will be computed as STRT-BOT rather than TOP-BOT. This option should be used with caution as it only affects conductance calculations in the NPF Package.
GWF	NPF	OPTIONS	VARIABLECV	KEYWORD	keyword to indicate that the vertical conductance will be calculated using the saturated thickness and properties of the overlying cell and the thickness and properties of the underlying cell. If the DEWATERED keyword is also specified, then the vertical conductance is calculated using only the saturated thickness and properties of the overlying cell if the head in the underlying cell is below its top. If these keywords are not specified, then the default condition is to calculate the vertical conductance at the start of the simulation using the initial head and the cell properties. The vertical conductance remains constant for the entire simulation.
GWF	NPF	OPTIONS	DEWATERED	KEYWORD	If the DEWATERED keyword is specified, then the vertical conductance is calculated using only the saturated thickness and properties of the overlying cell if the head in the underlying cell is below its top.
GWF	NPF	OPTIONS	PERCHED	KEYWORD	keyword to indicate that when a cell is overlying a dewatered convertible cell, the head difference used in Darcy's Law is equal to the head in the overlying cell minus the bottom elevation of the overlying cell. If not specified, then the default is to use the head difference between the two cells.
GWF	NPF	OPTIONS	REWET	KEYWORD	activates model rewetting. Rewetting is off by default.
GWF	NPF	OPTIONS	WETFCT	DOUBLE PRECISION	is a keyword and factor that is included in the calculation of the head that is initially established at a cell when that cell is converted from dry to wet.
GWF	NPF	OPTIONS	IWETIT	INTEGER	is a keyword and iteration interval for attempting to wet cells. Wetting is attempted every IWETIT iteration. This applies to outer iterations and not inner iterations. If IWETIT is specified as zero or less, then the value is changed to 1.
GWF	NPF	OPTIONS	IHDWET	INTEGER	is a keyword and integer flag that determines which equation is used to define the initial head at cells that become wet. If IHDWET is 0, h = BOT + WETFCT (hm - BOT). If IHDWET is not 0, h = BOT + WETFCT (THRESH).
GWF	NPF	OPTIONS	XT3D	KEYWORD	keyword indicating that the XT3D formulation will be used. If the RHS keyword is also included, then the XT3D additional terms will be added to the right-hand side. If the RHS keyword is excluded, then the XT3D terms will be put into the coefficient matrix. Use of XT3D will substantially increase the computational effort, but will result in improved accuracy for anisotropic conductivity fields and for unstructured grids in which the CVFD requirement is violated. XT3D requires additional information about the shapes of grid cells. If XT3D is active and the DISU Package is used, then the user will need to provide in the DISU Package the angldegx array in the CONNECTIONDATA block and the VERTICES and CELL2D blocks.
GWF	NPF	OPTIONS	RHS	KEYWORD	If the RHS keyword is also included, then the XT3D additional terms will be added to the right-hand side. If the RHS keyword is excluded, then the XT3D terms will be put into the coefficient matrix.
GWF	NPF	OPTIONS	SAVE_SPECIFIC_DISCHARGE	KEYWORD	keyword to indicate that x, y, and z components of specific discharge will be calculated at cell centers and written to the budget file, which is specified with ``BUDGET SAVE FILE'' in Output Control. If this option is activated, then additional information may be required in the discretization packages and the GWF Exchange package (if GWF models are coupled). Specifically, ANGLDEGX must be specified in the CONNECTIONDATA block of the DISU Package; ANGLDEGX must also be specified for the GWF Exchange as an auxiliary variable.
GWF	NPF	OPTIONS	SAVE_SATURATION	KEYWORD	keyword to indicate that cell saturation will be written to the budget file, which is specified with ``BUDGET SAVE FILE'' in Output Control. Saturation will be saved to the budget file as an auxiliary variable saved with the DATA-SAT text label. Saturation is a cell variable that ranges from zero to one and can be used by post processing programs to determine how much of a cell volume is saturated. If ICELLTYPE is 0, then saturation is always one.
GWF	NPF	OPTIONS	K22OVERK	KEYWORD	keyword to indicate that specified K22 is a ratio of K22 divided by K. If this option is specified, then the K22 array entered in the NPF Package will be multiplied by K after being read.
GWF	NPF	OPTIONS	K33OVERK	KEYWORD	keyword to indicate that specified K33 is a ratio of K33 divided by K. If this option is specified, then the K33 array entered in the NPF Package will be multiplied by K after being read.
GWF	NPF	OPTIONS	TVK6	KEYWORD	keyword to specify that record corresponds to a time-varying hydraulic conductivity (TVK) file. The behavior of TVK and a description of the input file is provided separately.
GWF	NPF	OPTIONS	FILEIN	KEYWORD	keyword to specify that an input filename is expected next.
GWF	NPF	OPTIONS	TVK6_FILENAME	STRING	defines a time-varying hydraulic conductivity (TVK) input file. Records in the TVK file can be used to change hydraulic conductivity properties at specified times or stress periods.
GWF	NPF	OPTIONS	DEV_NO_NEWTON	KEYWORD	turn off Newton for unconfined cells
GWF	NPF	OPTIONS	DEV_MODFLOWUSG_UPSTREAM_WEIGHTED_SATURATION	KEYWORD	use MODFLOW-USG upstream-weighted saturation approach
GWF	NPF	OPTIONS	DEV_MODFLOWNWT_UPSTREAM_WEIGHTING	KEYWORD	use MODFLOW-NWT approach for upstream weighting
GWF	NPF	OPTIONS	DEV_MINIMUM_SATURATED_THICKNESS	DOUBLE PRECISION	set minimum allowed saturated thickness
GWF	NPF	OPTIONS	DEV_OMEGA	DOUBLE PRECISION	set saturation omega value
GWF	NPF	GRIDDATA	ICELLTYPE	INTEGER (NODES)	flag for each cell that specifies how saturated thickness is treated. 0 means saturated thickness is held constant; $>$0 means saturated thickness varies with computed head when head is below the cell top; $<$0 means saturated thickness varies with computed head unless the THICKSTRT option is in effect. When THICKSTRT is in effect, a negative value for ICELLTYPE indicates that the saturated thickness value used in conductance calculations in the NPF Package will be computed as STRT-BOT and held constant. If the THICKSTRT option is not in effect, then negative values provided by the user for ICELLTYPE are automatically reassigned by the program to a value of one.
GWF	NPF	GRIDDATA	K	DOUBLE PRECISION (NODES)	is the hydraulic conductivity. For the common case in which the user would like to specify the horizontal hydraulic conductivity and the vertical hydraulic conductivity, then K should be assigned as the horizontal hydraulic conductivity, K33 should be assigned as the vertical hydraulic conductivity, and K22 and the three rotation angles should not be specified. When more sophisticated anisotropy is required, then K corresponds to the K11 hydraulic conductivity axis. All included cells (IDOMAIN $&gt;$ 0) must have a K value greater than zero.
GWF	NPF	GRIDDATA	K22	DOUBLE PRECISION (NODES)	is the hydraulic conductivity of the second ellipsoid axis (or the ratio of K22/K if the K22OVERK option is specified); for an unrotated case this is the hydraulic conductivity in the y direction. If K22 is not included in the GRIDDATA block, then K22 is set equal to K. For a regular MODFLOW grid (DIS Package is used) in which no rotation angles are specified, K22 is the hydraulic conductivity along columns in the y direction. For an unstructured DISU grid, the user must assign principal x and y axes and provide the angle for each cell face relative to the assigned x direction. All included cells (IDOMAIN $&gt;$ 0) must have a K22 value greater than zero.
GWF	NPF	GRIDDATA	K33	DOUBLE PRECISION (NODES)	is the hydraulic conductivity of the third ellipsoid axis (or the ratio of K33/K if the K33OVERK option is specified); for an unrotated case, this is the vertical hydraulic conductivity. When anisotropy is applied, K33 corresponds to the K33 tensor component. All included cells (IDOMAIN $&gt;$ 0) must have a K33 value greater than zero.
GWF	NPF	GRIDDATA	ANGLE1	DOUBLE PRECISION (NODES)	is a rotation angle of the hydraulic conductivity tensor in degrees. The angle represents the first of three sequential rotations of the hydraulic conductivity ellipsoid. With the K11, K22, and K33 axes of the ellipsoid initially aligned with the x, y, and z coordinate axes, respectively, ANGLE1 rotates the ellipsoid about its K33 axis (within the x - y plane). A positive value represents counter-clockwise rotation when viewed from any point on the positive K33 axis, looking toward the center of the ellipsoid. A value of zero indicates that the K11 axis lies within the x - z plane. If ANGLE1 is not specified, default values of zero are assigned to ANGLE1, ANGLE2, and ANGLE3, in which case the K11, K22, and K33 axes are aligned with the x, y, and z axes, respectively.
GWF	NPF	GRIDDATA	ANGLE2	DOUBLE PRECISION (NODES)	is a rotation angle of the hydraulic conductivity tensor in degrees. The angle represents the second of three sequential rotations of the hydraulic conductivity ellipsoid. Following the rotation by ANGLE1 described above, ANGLE2 rotates the ellipsoid about its K22 axis (out of the x - y plane). An array can be specified for ANGLE2 only if ANGLE1 is also specified. A positive value of ANGLE2 represents clockwise rotation when viewed from any point on the positive K22 axis, looking toward the center of the ellipsoid. A value of zero indicates that the K11 axis lies within the x - y plane. If ANGLE2 is not specified, default values of zero are assigned to ANGLE2 and ANGLE3; connections that are not user-designated as vertical are assumed to be strictly horizontal (that is, to have no z component to their orientation); and connection lengths are based on horizontal distances.
GWF	NPF	GRIDDATA	ANGLE3	DOUBLE PRECISION (NODES)	is a rotation angle of the hydraulic conductivity tensor in degrees. The angle represents the third of three sequential rotations of the hydraulic conductivity ellipsoid. Following the rotations by ANGLE1 and ANGLE2 described above, ANGLE3 rotates the ellipsoid about its K11 axis. An array can be specified for ANGLE3 only if ANGLE1 and ANGLE2 are also specified. An array must be specified for ANGLE3 if ANGLE2 is specified. A positive value of ANGLE3 represents clockwise rotation when viewed from any point on the positive K11 axis, looking toward the center of the ellipsoid. A value of zero indicates that the K22 axis lies within the x - y plane.
GWF	NPF	GRIDDATA	WETDRY	DOUBLE PRECISION (NODES)	is a combination of the wetting threshold and a flag to indicate which neighboring cells can cause a cell to become wet. If WETDRY $&lt;$ 0, only a cell below a dry cell can cause the cell to become wet. If WETDRY $&gt;$ 0, the cell below a dry cell and horizontally adjacent cells can cause a cell to become wet. If WETDRY is 0, the cell cannot be wetted. The absolute value of WETDRY is the wetting threshold. When the sum of BOT and the absolute value of WETDRY at a dry cell is equaled or exceeded by the head at an adjacent cell, the cell is wetted. WETDRY must be specified if REWET'' is specified in the OPTIONS block. If REWET'' is not specified in the options block, then WETDRY can be entered, and memory will be allocated for it, even though it is not used.
GWF	BUY	OPTIONS	HHFORMULATION_RHS	KEYWORD	use the variable-density hydraulic head formulation and add off-diagonal terms to the right-hand. This option will prevent the BUY Package from adding asymmetric terms to the flow matrix.
GWF	BUY	OPTIONS	DENSEREF	DOUBLE PRECISION	fluid reference density used in the equation of state. This value is set to 1000. if not specified as an option.
GWF	BUY	OPTIONS	DENSITY	KEYWORD	keyword to specify that record corresponds to density.
GWF	BUY	OPTIONS	FILEOUT	KEYWORD	keyword to specify that an output filename is expected next.
GWF	BUY	OPTIONS	DENSITYFILE	STRING	name of the binary output file to write density information. The density file has the same format as the head file. Density values will be written to the density file whenever heads are written to the binary head file. The settings for controlling head output are contained in the Output Control option.
GWF	BUY	OPTIONS	DEV_EFH_FORMULATION	KEYWORD	use the variable-density equivalent freshwater head formulation instead of the hydraulic head head formulation. This dev option has only been implemented for confined aquifer conditions and should generally not be used.
GWF	BUY	DIMENSIONS	NRHOSPECIES	INTEGER	number of species used in density equation of state. This value must be one or greater if the BUY package is activated.
GWF	BUY	PACKAGEDATA	IRHOSPEC	INTEGER	integer value that defines the species number associated with the specified PACKAGEDATA data on the line. IRHOSPECIES must be greater than zero and less than or equal to NRHOSPECIES. Information must be specified for each of the NRHOSPECIES species or the program will terminate with an error. The program will also terminate with an error if information for a species is specified more than once.
GWF	BUY	PACKAGEDATA	DRHODC	DOUBLE PRECISION	real value that defines the slope of the density-concentration line for this species used in the density equation of state.
GWF	BUY	PACKAGEDATA	CRHOREF	DOUBLE PRECISION	real value that defines the reference concentration value used for this species in the density equation of state.
GWF	BUY	PACKAGEDATA	MODELNAME	STRING	name of GWT model used to simulate a species that will be used in the density equation of state. This name will have no effect if the simulation does not include a GWT model that corresponds to this GWF model.
GWF	BUY	PACKAGEDATA	AUXSPECIESNAME	STRING	name of an auxiliary variable in a GWF stress package that will be used for this species to calculate a density value. If a density value is needed by the Buoyancy Package then it will use the concentration values in this AUXSPECIESNAME column in the density equation of state. For advanced stress packages (LAK, SFR, MAW, and UZF) that have an associated advanced transport package (LKT, SFT, MWT, and UZT), the FLOW_PACKAGE_AUXILIARY_NAME option in the advanced transport package can be used to transfer simulated concentrations into the flow package auxiliary variable. In this manner, the Buoyancy Package can calculate density values for lakes, streams, multi-aquifer wells, and unsaturated zone flow cells using simulated concentrations.
GWF	STO	OPTIONS	SAVE_FLOWS	KEYWORD	keyword to indicate that cell-by-cell flow terms will be written to the file specified with ``BUDGET SAVE FILE'' in Output Control.
GWF	STO	OPTIONS	STORAGECOEFFICIENT	KEYWORD	keyword to indicate that the SS array is read as storage coefficient rather than specific storage.
GWF	STO	OPTIONS	SS_CONFINED_ONLY	KEYWORD	keyword to indicate that compressible storage is only calculated for a convertible cell (ICONVERT>0) when the cell is under confined conditions (head greater than or equal to the top of the cell). This option has no effect on cells that are marked as being always confined (ICONVERT=0). This option is identical to the approach used to calculate storage changes under confined conditions in MODFLOW-2005.
GWF	STO	OPTIONS	TVS6	KEYWORD	keyword to specify that record corresponds to a time-varying storage (TVS) file. The behavior of TVS and a description of the input file is provided separately.
GWF	STO	OPTIONS	FILEIN	KEYWORD	keyword to specify that an input filename is expected next.
GWF	STO	OPTIONS	TVS_FILENAME	STRING	defines a time-varying storage (TVS) input file. Records in the TVS file can be used to change specific storage and specific yield properties at specified times or stress periods.
GWF	STO	GRIDDATA	ICONVERT	INTEGER (NODES)	is a flag for each cell that specifies whether or not a cell is convertible for the storage calculation. 0 indicates confined storage is used. $>$0 indicates confined storage is used when head is above cell top and a mixed formulation of unconfined and confined storage is used when head is below cell top.
GWF	STO	GRIDDATA	SS	DOUBLE PRECISION (NODES)	is specific storage (or the storage coefficient if STORAGECOEFFICIENT is specified as an option). Specific storage values must be greater than or equal to 0. If the CSUB Package is included in the GWF model, specific storage must be zero for every cell.
GWF	STO	GRIDDATA	SY	DOUBLE PRECISION (NODES)	is specific yield. Specific yield values must be greater than or equal to 0. Specific yield does not have to be specified if there are no convertible cells (ICONVERT=0 in every cell).
GWF	STO	PERIOD	IPER	INTEGER	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.
GWF	STO	PERIOD	STEADY-STATE	KEYWORD	keyword to indicate that stress period IPER is steady-state. Steady-state conditions will apply until the TRANSIENT keyword is specified in a subsequent BEGIN PERIOD block. If the CSUB Package is included in the GWF model, only the first and last stress period can be steady-state.
GWF	STO	PERIOD	TRANSIENT	KEYWORD	keyword to indicate that stress period IPER is transient. Transient conditions will apply until the STEADY-STATE keyword is specified in a subsequent BEGIN PERIOD block.
GWF	CSUB	OPTIONS	BOUNDNAMES	KEYWORD	keyword to indicate that boundary names may be provided with the list of CSUB cells.
GWF	CSUB	OPTIONS	PRINT_INPUT	KEYWORD	keyword to indicate that the list of CSUB information will be written to the listing file immediately after it is read.
GWF	CSUB	OPTIONS	SAVE_FLOWS	KEYWORD	keyword to indicate that cell-by-cell flow terms will be written to the file specified with ``BUDGET SAVE FILE'' in Output Control.
GWF	CSUB	OPTIONS	GAMMAW	DOUBLE PRECISION	unit weight of water. For freshwater, GAMMAW is 9806.65 Newtons/cubic meters or 62.48 lb/cubic foot in SI and English units, respectively. By default, GAMMAW is 9806.65 Newtons/cubic meters.
GWF	CSUB	OPTIONS	BETA	DOUBLE PRECISION	compressibility of water. Typical values of BETA are 4.6512e-10 1/Pa or 2.2270e-8 lb/square foot in SI and English units, respectively. By default, BETA is 4.6512e-10 1/Pa.
GWF	CSUB	OPTIONS	HEAD_BASED	KEYWORD	keyword to indicate the head-based formulation will be used to simulate coarse-grained aquifer materials and no-delay and delay interbeds. Specifying HEAD_BASED also specifies the INITIAL_PRECONSOLIDATION_HEAD option.
GWF	CSUB	OPTIONS	INITIAL_PRECONSOLIDATION_HEAD	KEYWORD	keyword to indicate that preconsolidation heads will be specified for no-delay and delay interbeds in the PACKAGEDATA block. If the SPECIFIED_INITIAL_INTERBED_STATE option is specified in the OPTIONS block, user-specified preconsolidation heads in the PACKAGEDATA block are absolute values. Otherwise, user-specified preconsolidation heads in the PACKAGEDATA block are relative to steady-state or initial heads.
GWF	CSUB	OPTIONS	NDELAYCELLS	INTEGER	number of nodes used to discretize delay interbeds. If not specified, then a default value of 19 is assigned.
GWF	CSUB	OPTIONS	COMPRESSION_INDICES	KEYWORD	keyword to indicate that the recompression (CR) and compression (CC) indices are specified instead of the elastic specific storage (SSE) and inelastic specific storage (SSV) coefficients. If not specified, then elastic specific storage (SSE) and inelastic specific storage (SSV) coefficients must be specified.
GWF	CSUB	OPTIONS	UPDATE_MATERIAL_PROPERTIES	KEYWORD	keyword to indicate that the thickness and void ratio of coarse-grained and interbed sediments (delay and no-delay) will vary during the simulation. If not specified, the thickness and void ratio of coarse-grained and interbed sediments will not vary during the simulation.
GWF	CSUB	OPTIONS	CELL_FRACTION	KEYWORD	keyword to indicate that the thickness of interbeds will be specified in terms of the fraction of cell thickness. If not specified, interbed thicknness must be specified.
GWF	CSUB	OPTIONS	SPECIFIED_INITIAL_INTERBED_STATE	KEYWORD	keyword to indicate that absolute preconsolidation stresses (heads) and delay bed heads will be specified for interbeds defined in the PACKAGEDATA block. The SPECIFIED_INITIAL_INTERBED_STATE option is equivalent to specifying the SPECIFIED_INITIAL_PRECONSOLITATION_STRESS and SPECIFIED_INITIAL_DELAY_HEAD. If SPECIFIED_INITIAL_INTERBED_STATE is not specified then preconsolidation stress (head) and delay bed head values specified in the PACKAGEDATA block are relative to simulated values of the first stress period if steady-state or initial stresses and GWF heads if the first stress period is transient.
GWF	CSUB	OPTIONS	SPECIFIED_INITIAL_PRECONSOLIDATION_STRESS	KEYWORD	keyword to indicate that absolute preconsolidation stresses (heads) will be specified for interbeds defined in the PACKAGEDATA block. If SPECIFIED_INITIAL_PRECONSOLITATION_STRESS and SPECIFIED_INITIAL_INTERBED_STATE are not specified then preconsolidation stress (head) values specified in the PACKAGEDATA block are relative to simulated values if the first stress period is steady-state or initial stresses (heads) if the first stress period is transient.
GWF	CSUB	OPTIONS	SPECIFIED_INITIAL_DELAY_HEAD	KEYWORD	keyword to indicate that absolute initial delay bed head will be specified for interbeds defined in the PACKAGEDATA block. If SPECIFIED_INITIAL_DELAY_HEAD and SPECIFIED_INITIAL_INTERBED_STATE are not specified then delay bed head values specified in the PACKAGEDATA block are relative to simulated values if the first stress period is steady-state or initial GWF heads if the first stress period is transient.
GWF	CSUB	OPTIONS	EFFECTIVE_STRESS_LAG	KEYWORD	keyword to indicate the effective stress from the previous time step will be used to calculate specific storage values. This option can 1) help with convergence in models with thin cells and water table elevations close to land surface; 2) is identical to the approach used in the SUBWT package for MODFLOW-2005; and 3) is only used if the effective-stress formulation is being used. By default, current effective stress values are used to calculate specific storage values.
GWF	CSUB	OPTIONS	STRAIN_CSV_INTERBED	KEYWORD	keyword to specify the record that corresponds to final interbed strain output.
GWF	CSUB	OPTIONS	FILEOUT	KEYWORD	keyword to specify that an output filename is expected next.
GWF	CSUB	OPTIONS	INTERBEDSTRAIN_FILENAME	STRING	name of the comma-separated-values output file to write final interbed strain information.
GWF	CSUB	OPTIONS	STRAIN_CSV_COARSE	KEYWORD	keyword to specify the record that corresponds to final coarse-grained material strain output.
GWF	CSUB	OPTIONS	COARSESTRAIN_FILENAME	STRING	name of the comma-separated-values output file to write final coarse-grained material strain information.
GWF	CSUB	OPTIONS	COMPACTION	KEYWORD	keyword to specify that record corresponds to the compaction.
GWF	CSUB	OPTIONS	COMPACTION_FILENAME	STRING	name of the binary output file to write compaction information.
GWF	CSUB	OPTIONS	COMPACTION_ELASTIC	KEYWORD	keyword to specify that record corresponds to the elastic interbed compaction binary file.
GWF	CSUB	OPTIONS	ELASTIC_COMPACTION_FILENAME	STRING	name of the binary output file to write elastic interbed compaction information.
GWF	CSUB	OPTIONS	COMPACTION_INELASTIC	KEYWORD	keyword to specify that record corresponds to the inelastic interbed compaction binary file.
GWF	CSUB	OPTIONS	INELASTIC_COMPACTION_FILENAME	STRING	name of the binary output file to write inelastic interbed compaction information.
GWF	CSUB	OPTIONS	COMPACTION_INTERBED	KEYWORD	keyword to specify that record corresponds to the interbed compaction binary file.
GWF	CSUB	OPTIONS	INTERBED_COMPACTION_FILENAME	STRING	name of the binary output file to write interbed compaction information.
GWF	CSUB	OPTIONS	COMPACTION_COARSE	KEYWORD	keyword to specify that record corresponds to the elastic coarse-grained material compaction binary file.
GWF	CSUB	OPTIONS	COARSE_COMPACTION_FILENAME	STRING	name of the binary output file to write elastic coarse-grained material compaction information.
GWF	CSUB	OPTIONS	ZDISPLACEMENT	KEYWORD	keyword to specify that record corresponds to the z-displacement binary file.
GWF	CSUB	OPTIONS	ZDISPLACEMENT_FILENAME	STRING	name of the binary output file to write z-displacement information.
GWF	CSUB	OPTIONS	PACKAGE_CONVERGENCE	KEYWORD	keyword to specify that record corresponds to the package convergence comma spaced values file.
GWF	CSUB	OPTIONS	PACKAGE_CONVERGENCE_FILENAME	STRING	name of the comma spaced values output file to write package convergence information.
GWF	CSUB	OPTIONS	TS6	KEYWORD	keyword to specify that record corresponds to a time-series file.
GWF	CSUB	OPTIONS	FILEIN	KEYWORD	keyword to specify that an input filename is expected next.
GWF	CSUB	OPTIONS	TS6_FILENAME	STRING	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.
GWF	CSUB	OPTIONS	OBS6	KEYWORD	keyword to specify that record corresponds to an observations file.
GWF	CSUB	OPTIONS	OBS6_FILENAME	STRING	name of input file to define observations for the CSUB package. See the ``Observation utility'' section for instructions for preparing observation input files. Tables \ref{table:gwf-obstypetable} and \ref{table:gwt-obstypetable} lists observation type(s) supported by the CSUB package.
GWF	CSUB	DIMENSIONS	NINTERBEDS	INTEGER	is the number of CSUB interbed systems. More than 1 CSUB interbed systems can be assigned to a GWF cell; however, only 1 GWF cell can be assigned to a single CSUB interbed system.
GWF	CSUB	DIMENSIONS	MAXSIG0	INTEGER	is the maximum number of cells that can have a specified stress offset. More than 1 stress offset can be assigned to a GWF cell. By default, MAXSIG0 is 0.
GWF	CSUB	GRIDDATA	CG_SKE_CR	DOUBLE PRECISION (NODES)	is the initial elastic coarse-grained material specific storage or recompression index. The recompression index is specified if COMPRESSION_INDICES is specified in the OPTIONS block. Specified or calculated elastic coarse-grained material specific storage values are not adjusted from initial values if HEAD_BASED is specified in the OPTIONS block.
GWF	CSUB	GRIDDATA	CG_THETA	DOUBLE PRECISION (NODES)	is the initial porosity of coarse-grained materials.
GWF	CSUB	GRIDDATA	SGM	DOUBLE PRECISION (NODES)	is the specific gravity of moist or unsaturated sediments. If not specified, then a default value of 1.7 is assigned.
GWF	CSUB	GRIDDATA	SGS	DOUBLE PRECISION (NODES)	is the specific gravity of saturated sediments. If not specified, then a default value of 2.0 is assigned.
GWF	CSUB	PACKAGEDATA	ICSUBNO	INTEGER	integer value that defines the CSUB interbed number associated with the specified PACKAGEDATA data on the line. CSUBNO must be greater than zero and less than or equal to NINTERBEDS. CSUB information must be specified for every CSUB cell or the program will terminate with an error. The program will also terminate with an error if information for a CSUB interbed number is specified more than once.
GWF	CSUB	PACKAGEDATA	CELLID	INTEGER (NCELLDIM)	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.
GWF	CSUB	PACKAGEDATA	CDELAY	STRING	character string that defines the subsidence delay type for the interbed. Possible subsidence package CDELAY strings include: NODELAY--character keyword to indicate that delay will not be simulated in the interbed. DELAY--character keyword to indicate that delay will be simulated in the interbed.
GWF	CSUB	PACKAGEDATA	PCS0	DOUBLE PRECISION	is the initial offset from the calculated initial effective stress or initial preconsolidation stress in the interbed, in units of height of a column of water. PCS0 is the initial preconsolidation stress if SPECIFIED_INITIAL_INTERBED_STATE or SPECIFIED_INITIAL_PRECONSOLIDATION_STRESS are specified in the OPTIONS block. If HEAD_BASED is specified in the OPTIONS block, PCS0 is the initial offset from the calculated initial head or initial preconsolidation head in the CSUB interbed and the initial preconsolidation stress is calculated from the calculated initial effective stress or calculated initial geostatic stress, respectively.
GWF	CSUB	PACKAGEDATA	THICK_FRAC	DOUBLE PRECISION	is the interbed thickness or cell fraction of the interbed. Interbed thickness is specified as a fraction of the cell thickness if CELL_FRACTION is specified in the OPTIONS block.
GWF	CSUB	PACKAGEDATA	RNB	DOUBLE PRECISION	is the interbed material factor equivalent number of interbeds in the interbed system represented by the interbed. RNB must be greater than or equal to 1 if CDELAY is DELAY. Otherwise, RNB can be any value.
GWF	CSUB	PACKAGEDATA	SSV_CC	DOUBLE PRECISION	is the initial inelastic specific storage or compression index of the interbed. The compression index is specified if COMPRESSION_INDICES is specified in the OPTIONS block. Specified or calculated interbed inelastic specific storage values are not adjusted from initial values if HEAD_BASED is specified in the OPTIONS block.
GWF	CSUB	PACKAGEDATA	SSE_CR	DOUBLE PRECISION	is the initial elastic coarse-grained material specific storage or recompression index of the interbed. The recompression index is specified if COMPRESSION_INDICES is specified in the OPTIONS block. Specified or calculated interbed elastic specific storage values are not adjusted from initial values if HEAD_BASED is specified in the OPTIONS block.
GWF	CSUB	PACKAGEDATA	THETA	DOUBLE PRECISION	is the initial porosity of the interbed.
GWF	CSUB	PACKAGEDATA	KV	DOUBLE PRECISION	is the vertical hydraulic conductivity of the delay interbed. KV must be greater than 0 if CDELAY is DELAY. Otherwise, KV can be any value.
GWF	CSUB	PACKAGEDATA	H0	DOUBLE PRECISION	is the initial offset from the head in cell cellid or the initial head in the delay interbed. H0 is the initial head in the delay bed if SPECIFIED_INITIAL_INTERBED_STATE or SPECIFIED_INITIAL_DELAY_HEAD are specified in the OPTIONS block. H0 can be any value if CDELAY is NODELAY.
GWF	CSUB	PACKAGEDATA	BOUNDNAME	STRING	name of the CSUB 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.
GWF	CSUB	PERIOD	IPER	INTEGER	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.
GWF	CSUB	PERIOD	CELLID	INTEGER (NCELLDIM)	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.
GWF	CSUB	PERIOD	SIG0	DOUBLE PRECISION	is the stress offset for the cell. SIG0 is added to the calculated geostatic stress for the cell. SIG0 is specified only if MAXSIG0 is specified to be greater than 0 in the DIMENSIONS block. 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.
GWF	HFB	OPTIONS	PRINT_INPUT	KEYWORD	keyword to indicate that the list of horizontal flow barriers will be written to the listing file immediately after it is read.
GWF	HFB	DIMENSIONS	MAXHFB	INTEGER	integer value specifying the maximum number of horizontal flow barriers that will be entered in this input file. The value of MAXHFB is used to allocate memory for the horizontal flow barriers.
GWF	HFB	PERIOD	IPER	INTEGER	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.
GWF	HFB	PERIOD	CELLID1	INTEGER (NCELLDIM)	identifier for the first cell. For a structured grid that uses the DIS input file, CELLID1 is the layer, row, and column numbers of the cell. For a grid that uses the DISV input file, CELLID1 is the layer number and CELL2D number for the two cells. If the model uses the unstructured discretization (DISU) input file, then CELLID1 is the node numbers for the cell. The barrier is located between cells designated as CELLID1 and CELLID2. For models that use the DIS and DISV grid types, the layer number for CELLID1 and CELLID2 must be the same. For all grid types, cells must be horizontally adjacent or the program will terminate with an error.
GWF	HFB	PERIOD	CELLID2	INTEGER (NCELLDIM)	identifier for the second cell. See CELLID1 for description of how to specify.
GWF	HFB	PERIOD	HYDCHR	DOUBLE PRECISION	is the hydraulic characteristic of the horizontal-flow barrier. The hydraulic characteristic is the barrier hydraulic conductivity divided by the width of the horizontal-flow barrier. If the hydraulic characteristic is negative, then the absolute value of HYDCHR acts as a multiplier to the conductance between the two model cells specified as containing the barrier. For example, if the value for HYDCHR was specified as -1.5, the conductance calculated for the two cells would be multiplied by 1.5.
GWF	CHD	OPTIONS	AUXILIARY	STRING (NAUX)	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.
GWF	CHD	OPTIONS	AUXMULTNAME	STRING	name of auxiliary variable to be used as multiplier of CHD head value.
GWF	CHD	OPTIONS	BOUNDNAMES	KEYWORD	keyword to indicate that boundary names may be provided with the list of constant-head cells.
GWF	CHD	OPTIONS	PRINT_INPUT	KEYWORD	keyword to indicate that the list of constant-head information will be written to the listing file immediately after it is read.
GWF	CHD	OPTIONS	PRINT_FLOWS	KEYWORD	keyword to indicate that the list of constant-head 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.
GWF	CHD	OPTIONS	SAVE_FLOWS	KEYWORD	keyword to indicate that constant-head flow terms will be written to the file specified with ``BUDGET FILEOUT'' in Output Control.
GWF	CHD	OPTIONS	TS6	KEYWORD	keyword to specify that record corresponds to a time-series file.
GWF	CHD	OPTIONS	FILEIN	KEYWORD	keyword to specify that an input filename is expected next.
GWF	CHD	OPTIONS	TS6_FILENAME	STRING	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.
GWF	CHD	OPTIONS	OBS6	KEYWORD	keyword to specify that record corresponds to an observations file.
GWF	CHD	OPTIONS	OBS6_FILENAME	STRING	name of input file to define observations for the constant-head package. See the ``Observation utility'' section for instructions for preparing observation input files. Tables \ref{table:gwf-obstypetable} and \ref{table:gwt-obstypetable} lists observation type(s) supported by the constant-head package.
GWF	CHD	DIMENSIONS	MAXBOUND	INTEGER	integer value specifying the maximum number of constant-head cells that will be specified for use during any stress period.
GWF	CHD	PERIOD	IPER	INTEGER	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.
GWF	CHD	PERIOD	CELLID	INTEGER (NCELLDIM)	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.
GWF	CHD	PERIOD	HEAD	DOUBLE PRECISION	is the head at the boundary. 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.
GWF	CHD	PERIOD	AUX	DOUBLE PRECISION (NAUX)	represents the values of the auxiliary variables for each constant head. The values of auxiliary variables must be present for each constant head. 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.
GWF	CHD	PERIOD	BOUNDNAME	STRING	name of the constant head boundary 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.
GWF	WEL	OPTIONS	AUXILIARY	STRING (NAUX)	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.
GWF	WEL	OPTIONS	AUXMULTNAME	STRING	name of auxiliary variable to be used as multiplier of well flow rate.
GWF	WEL	OPTIONS	BOUNDNAMES	KEYWORD	keyword to indicate that boundary names may be provided with the list of well cells.
GWF	WEL	OPTIONS	PRINT_INPUT	KEYWORD	keyword to indicate that the list of well information will be written to the listing file immediately after it is read.
GWF	WEL	OPTIONS	PRINT_FLOWS	KEYWORD	keyword to indicate that the list of well 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.
GWF	WEL	OPTIONS	SAVE_FLOWS	KEYWORD	keyword to indicate that well flow terms will be written to the file specified with ``BUDGET FILEOUT'' in Output Control.
GWF	WEL	OPTIONS	AUTO_FLOW_REDUCE	DOUBLE PRECISION	keyword and real value that defines the fraction of the cell thickness used as an interval for smoothly adjusting negative pumping rates to 0 in cells with head values less than or equal to the bottom of the cell. Negative pumping rates are adjusted to 0 or a smaller negative value when the head in the cell is equal to or less than the calculated interval above the cell bottom. AUTO_FLOW_REDUCE is set to 0.1 if the specified value is less than or equal to zero. By default, negative pumping rates are not reduced during a simulation.
GWF	WEL	OPTIONS	AUTO_FLOW_REDUCE_CSV	KEYWORD	keyword to specify that record corresponds to the AUTO_FLOW_REDUCE output option in which a new record is written for each well and for each time step in which the user-requested extraction rate is reduced by the program.
GWF	WEL	OPTIONS	FILEOUT	KEYWORD	keyword to specify that an output filename is expected next.
GWF	WEL	OPTIONS	AFRCSVFILE	STRING	name of the comma-separated value (CSV) output file to write information about well extraction rates that have been reduced by the program. Entries are only written if the extraction rates are reduced.
GWF	WEL	OPTIONS	TS6	KEYWORD	keyword to specify that record corresponds to a time-series file.
GWF	WEL	OPTIONS	FILEIN	KEYWORD	keyword to specify that an input filename is expected next.
GWF	WEL	OPTIONS	TS6_FILENAME	STRING	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.
GWF	WEL	OPTIONS	OBS6	KEYWORD	keyword to specify that record corresponds to an observations file.
GWF	WEL	OPTIONS	OBS6_FILENAME	STRING	name of input file to define observations for the Well package. See the ``Observation utility'' section for instructions for preparing observation input files. Tables \ref{table:gwf-obstypetable} and \ref{table:gwt-obstypetable} lists observation type(s) supported by the Well package.
GWF	WEL	OPTIONS	MOVER	KEYWORD	keyword to indicate that this instance of the Well Package can be used with the Water Mover (MVR) Package. When the MOVER option is specified, additional memory is allocated within the package to store the available, provided, and received water.
GWF	WEL	DIMENSIONS	MAXBOUND	INTEGER	integer value specifying the maximum number of wells cells that will be specified for use during any stress period.
GWF	WEL	PERIOD	IPER	INTEGER	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.
GWF	WEL	PERIOD	CELLID	INTEGER (NCELLDIM)	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.
GWF	WEL	PERIOD	Q	DOUBLE PRECISION	is the volumetric well rate. A positive value indicates recharge (injection) and a negative value indicates discharge (extraction). 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.
GWF	WEL	PERIOD	AUX	DOUBLE PRECISION (NAUX)	represents the values of the auxiliary variables for each well. The values of auxiliary variables must be present for each well. 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.
GWF	WEL	PERIOD	BOUNDNAME	STRING	name of the well 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.
GWF	DRN	OPTIONS	AUXILIARY	STRING (NAUX)	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.
GWF	DRN	OPTIONS	AUXMULTNAME	STRING	name of auxiliary variable to be used as multiplier of drain conductance.
GWF	DRN	OPTIONS	AUXDEPTHNAME	STRING	name of a variable listed in AUXILIARY that defines the depth at which drainage discharge will be scaled. If a positive value is specified for the AUXDEPTHNAME AUXILIARY variable, then ELEV is the elevation at which the drain starts to discharge and ELEV + DDRN (assuming DDRN is the AUXDEPTHNAME variable) is the elevation when the drain conductance (COND) scaling factor is 1. If a negative drainage depth value is specified for DDRN, then ELEV + DDRN is the elevation at which the drain starts to discharge and ELEV is the elevation when the conductance (COND) scaling factor is 1. A linear- or cubic-scaling is used to scale the drain conductance (COND) when the Standard or Newton-Raphson Formulation is used, respectively. This discharge scaling option is described in more detail in Chapter 3 of the Supplemental Technical Information.
GWF	DRN	OPTIONS	BOUNDNAMES	KEYWORD	keyword to indicate that boundary names may be provided with the list of drain cells.
GWF	DRN	OPTIONS	PRINT_INPUT	KEYWORD	keyword to indicate that the list of drain information will be written to the listing file immediately after it is read.
GWF	DRN	OPTIONS	PRINT_FLOWS	KEYWORD	keyword to indicate that the list of drain 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.
GWF	DRN	OPTIONS	SAVE_FLOWS	KEYWORD	keyword to indicate that drain flow terms will be written to the file specified with ``BUDGET FILEOUT'' in Output Control.
GWF	DRN	OPTIONS	TS6	KEYWORD	keyword to specify that record corresponds to a time-series file.
GWF	DRN	OPTIONS	FILEIN	KEYWORD	keyword to specify that an input filename is expected next.
GWF	DRN	OPTIONS	TS6_FILENAME	STRING	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.
GWF	DRN	OPTIONS	OBS6	KEYWORD	keyword to specify that record corresponds to an observations file.
GWF	DRN	OPTIONS	OBS6_FILENAME	STRING	name of input file to define observations for the Drain package. See the ``Observation utility'' section for instructions for preparing observation input files. Tables \ref{table:gwf-obstypetable} and \ref{table:gwt-obstypetable} lists observation type(s) supported by the Drain package.
GWF	DRN	OPTIONS	MOVER	KEYWORD	keyword to indicate that this instance of the Drain Package can be used with the Water Mover (MVR) Package. When the MOVER option is specified, additional memory is allocated within the package to store the available, provided, and received water.
GWF	DRN	DIMENSIONS	MAXBOUND	INTEGER	integer value specifying the maximum number of drains cells that will be specified for use during any stress period.
GWF	DRN	PERIOD	IPER	INTEGER	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.
GWF	DRN	PERIOD	CELLID	INTEGER (NCELLDIM)	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.
GWF	DRN	PERIOD	ELEV	DOUBLE PRECISION	is the elevation of the drain. 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.
GWF	DRN	PERIOD	COND	DOUBLE PRECISION	is the hydraulic conductance of the interface between the aquifer and the drain. 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.
GWF	DRN	PERIOD	AUX	DOUBLE PRECISION (NAUX)	represents the values of the auxiliary variables for each drain. The values of auxiliary variables must be present for each drain. 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.
GWF	DRN	PERIOD	BOUNDNAME	STRING	name of the drain 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.
GWF	RIV	OPTIONS	AUXILIARY	STRING (NAUX)	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.
GWF	RIV	OPTIONS	AUXMULTNAME	STRING	name of auxiliary variable to be used as multiplier of riverbed conductance.
GWF	RIV	OPTIONS	BOUNDNAMES	KEYWORD	keyword to indicate that boundary names may be provided with the list of river cells.
GWF	RIV	OPTIONS	PRINT_INPUT	KEYWORD	keyword to indicate that the list of river information will be written to the listing file immediately after it is read.
GWF	RIV	OPTIONS	PRINT_FLOWS	KEYWORD	keyword to indicate that the list of river 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.
GWF	RIV	OPTIONS	SAVE_FLOWS	KEYWORD	keyword to indicate that river flow terms will be written to the file specified with ``BUDGET FILEOUT'' in Output Control.
GWF	RIV	OPTIONS	TS6	KEYWORD	keyword to specify that record corresponds to a time-series file.
GWF	RIV	OPTIONS	FILEIN	KEYWORD	keyword to specify that an input filename is expected next.
GWF	RIV	OPTIONS	TS6_FILENAME	STRING	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.
GWF	RIV	OPTIONS	OBS6	KEYWORD	keyword to specify that record corresponds to an observations file.
GWF	RIV	OPTIONS	OBS6_FILENAME	STRING	name of input file to define observations for the River package. See the ``Observation utility'' section for instructions for preparing observation input files. Tables \ref{table:gwf-obstypetable} and \ref{table:gwt-obstypetable} lists observation type(s) supported by the River package.
GWF	RIV	OPTIONS	MOVER	KEYWORD	keyword to indicate that this instance of the River Package can be used with the Water Mover (MVR) Package. When the MOVER option is specified, additional memory is allocated within the package to store the available, provided, and received water.
GWF	RIV	DIMENSIONS	MAXBOUND	INTEGER	integer value specifying the maximum number of rivers cells that will be specified for use during any stress period.
GWF	RIV	PERIOD	IPER	INTEGER	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.
GWF	RIV	PERIOD	CELLID	INTEGER (NCELLDIM)	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.
GWF	RIV	PERIOD	STAGE	DOUBLE PRECISION	is the head in the river. 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.
GWF	RIV	PERIOD	COND	DOUBLE PRECISION	is the riverbed hydraulic conductance. 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.
GWF	RIV	PERIOD	RBOT	DOUBLE PRECISION	is the elevation of the bottom of the riverbed. 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.
GWF	RIV	PERIOD	AUX	DOUBLE PRECISION (NAUX)	represents the values of the auxiliary variables for each river. The values of auxiliary variables must be present for each river. 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.
GWF	RIV	PERIOD	BOUNDNAME	STRING	name of the river 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.
GWF	GHB	OPTIONS	AUXILIARY	STRING (NAUX)	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.
GWF	GHB	OPTIONS	AUXMULTNAME	STRING	name of auxiliary variable to be used as multiplier of general-head boundary conductance.
GWF	GHB	OPTIONS	BOUNDNAMES	KEYWORD	keyword to indicate that boundary names may be provided with the list of general-head boundary cells.
GWF	GHB	OPTIONS	PRINT_INPUT	KEYWORD	keyword to indicate that the list of general-head boundary information will be written to the listing file immediately after it is read.
GWF	GHB	OPTIONS	PRINT_FLOWS	KEYWORD	keyword to indicate that the list of general-head boundary 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.
GWF	GHB	OPTIONS	SAVE_FLOWS	KEYWORD	keyword to indicate that general-head boundary flow terms will be written to the file specified with ``BUDGET FILEOUT'' in Output Control.
GWF	GHB	OPTIONS	TS6	KEYWORD	keyword to specify that record corresponds to a time-series file.
GWF	GHB	OPTIONS	FILEIN	KEYWORD	keyword to specify that an input filename is expected next.
GWF	GHB	OPTIONS	TS6_FILENAME	STRING	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.
GWF	GHB	OPTIONS	OBS6	KEYWORD	keyword to specify that record corresponds to an observations file.
GWF	GHB	OPTIONS	OBS6_FILENAME	STRING	name of input file to define observations for the General-Head Boundary package. See the ``Observation utility'' section for instructions for preparing observation input files. Tables \ref{table:gwf-obstypetable} and \ref{table:gwt-obstypetable} lists observation type(s) supported by the General-Head Boundary package.
GWF	GHB	OPTIONS	MOVER	KEYWORD	keyword to indicate that this instance of the General-Head Boundary Package can be used with the Water Mover (MVR) Package. When the MOVER option is specified, additional memory is allocated within the package to store the available, provided, and received water.
GWF	GHB	DIMENSIONS	MAXBOUND	INTEGER	integer value specifying the maximum number of general-head boundary cells that will be specified for use during any stress period.
GWF	GHB	PERIOD	IPER	INTEGER	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.
GWF	GHB	PERIOD	CELLID	INTEGER (NCELLDIM)	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.
GWF	GHB	PERIOD	BHEAD	DOUBLE PRECISION	is the boundary head. 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.
GWF	GHB	PERIOD	COND	DOUBLE PRECISION	is the hydraulic conductance of the interface between the aquifer cell and the boundary. 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.
GWF	GHB	PERIOD	AUX	DOUBLE PRECISION (NAUX)	represents the values of the auxiliary variables for each general-head boundary. The values of auxiliary variables must be present for each general-head boundary. 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.
GWF	GHB	PERIOD	BOUNDNAME	STRING	name of the general-head boundary 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.
GWF	RCH	OPTIONS	FIXED_CELL	KEYWORD	indicates that recharge will not be reassigned to a cell underlying the cell specified in the list if the specified cell is inactive.
GWF	RCH	OPTIONS	AUXILIARY	STRING (NAUX)	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.
GWF	RCH	OPTIONS	AUXMULTNAME	STRING	name of auxiliary variable to be used as multiplier of recharge.
GWF	RCH	OPTIONS	BOUNDNAMES	KEYWORD	keyword to indicate that boundary names may be provided with the list of recharge cells.
GWF	RCH	OPTIONS	PRINT_INPUT	KEYWORD	keyword to indicate that the list of recharge information will be written to the listing file immediately after it is read.
GWF	RCH	OPTIONS	PRINT_FLOWS	KEYWORD	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.
GWF	RCH	OPTIONS	SAVE_FLOWS	KEYWORD	keyword to indicate that recharge flow terms will be written to the file specified with ``BUDGET FILEOUT'' in Output Control.
GWF	RCH	OPTIONS	TS6	KEYWORD	keyword to specify that record corresponds to a time-series file.
GWF	RCH	OPTIONS	FILEIN	KEYWORD	keyword to specify that an input filename is expected next.
GWF	RCH	OPTIONS	TS6_FILENAME	STRING	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.
GWF	RCH	OPTIONS	OBS6	KEYWORD	keyword to specify that record corresponds to an observations file.
GWF	RCH	OPTIONS	OBS6_FILENAME	STRING	name of input file to define observations for the Recharge package. See the ``Observation utility'' section for instructions for preparing observation input files. Tables \ref{table:gwf-obstypetable} and \ref{table:gwt-obstypetable} lists observation type(s) supported by the Recharge package.
GWF	RCH	DIMENSIONS	MAXBOUND	INTEGER	integer value specifying the maximum number of recharge cells cells that will be specified for use during any stress period.
GWF	RCH	PERIOD	IPER	INTEGER	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.
GWF	RCH	PERIOD	CELLID	INTEGER (NCELLDIM)	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.
GWF	RCH	PERIOD	RECHARGE	DOUBLE PRECISION	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.
GWF	RCH	PERIOD	AUX	DOUBLE PRECISION (NAUX)	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.
GWF	RCH	PERIOD	BOUNDNAME	STRING	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.
GWF	RCHA	OPTIONS	READASARRAYS	KEYWORD	indicates that array-based input will be used for the Recharge Package. This keyword must be specified to use array-based input.
GWF	RCHA	OPTIONS	FIXED_CELL	KEYWORD	indicates that recharge will not be reassigned to a cell underlying the cell specified in the list if the specified cell is inactive.
GWF	RCHA	OPTIONS	AUXILIARY	STRING (NAUX)	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.
GWF	RCHA	OPTIONS	AUXMULTNAME	STRING	name of auxiliary variable to be used as multiplier of recharge.
GWF	RCHA	OPTIONS	PRINT_INPUT	KEYWORD	keyword to indicate that the list of recharge information will be written to the listing file immediately after it is read.
GWF	RCHA	OPTIONS	PRINT_FLOWS	KEYWORD	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.
GWF	RCHA	OPTIONS	SAVE_FLOWS	KEYWORD	keyword to indicate that recharge flow terms will be written to the file specified with ``BUDGET FILEOUT'' in Output Control.
GWF	RCHA	OPTIONS	TAS6	KEYWORD	keyword to specify that record corresponds to a time-array-series file.
GWF	RCHA	OPTIONS	FILEIN	KEYWORD	keyword to specify that an input filename is expected next.
GWF	RCHA	OPTIONS	TAS6_FILENAME	STRING	defines a time-array-series file defining a time-array series that can be used to assign time-varying values. See the Time-Variable Input section for instructions on using the time-array series capability.
GWF	RCHA	OPTIONS	OBS6	KEYWORD	keyword to specify that record corresponds to an observations file.
GWF	RCHA	OPTIONS	OBS6_FILENAME	STRING	name of input file to define observations for the Recharge package. See the ``Observation utility'' section for instructions for preparing observation input files. Tables \ref{table:gwf-obstypetable} and \ref{table:gwt-obstypetable} lists observation type(s) supported by the Recharge package.
GWF	RCHA	PERIOD	IPER	INTEGER	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.
GWF	RCHA	PERIOD	IRCH	INTEGER (NCOL*NROW; NCPL)	IRCH is the layer number that defines the layer in each vertical column where recharge is applied. If IRCH is omitted, recharge by default is applied to cells in layer 1. IRCH can only be used if READASARRAYS is specified in the OPTIONS block. If IRCH is specified, it must be specified as the first variable in the PERIOD block or MODFLOW will terminate with an error.
GWF	RCHA	PERIOD	RECHARGE	DOUBLE PRECISION (NCOL*NROW; NCPL)	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. The recharge array may be defined by a time-array series (see the "Using Time-Array Series in a Package" section).
GWF	RCHA	PERIOD	AUX	DOUBLE PRECISION (NCOL*NROW; NCPL)	is an array of values for auxiliary variable aux(iaux), where iaux is a value from 1 to naux, and aux(iaux) must be listed as part of the auxiliary variables. A separate array can be specified for each auxiliary variable. If an array is not specified for an auxiliary variable, then a value of zero is assigned. If the value specified here for the auxiliary variable is the same as auxmultname, then the recharge array will be multiplied by this array.
GWF	EVT	OPTIONS	FIXED_CELL	KEYWORD	indicates that evapotranspiration will not be reassigned to a cell underlying the cell specified in the list if the specified cell is inactive.
GWF	EVT	OPTIONS	AUXILIARY	STRING (NAUX)	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.
GWF	EVT	OPTIONS	AUXMULTNAME	STRING	name of auxiliary variable to be used as multiplier of evapotranspiration rate.
GWF	EVT	OPTIONS	BOUNDNAMES	KEYWORD	keyword to indicate that boundary names may be provided with the list of evapotranspiration cells.
GWF	EVT	OPTIONS	PRINT_INPUT	KEYWORD	keyword to indicate that the list of evapotranspiration information will be written to the listing file immediately after it is read.
GWF	EVT	OPTIONS	PRINT_FLOWS	KEYWORD	keyword to indicate that the list of evapotranspiration 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.
GWF	EVT	OPTIONS	SAVE_FLOWS	KEYWORD	keyword to indicate that evapotranspiration flow terms will be written to the file specified with ``BUDGET FILEOUT'' in Output Control.
GWF	EVT	OPTIONS	TS6	KEYWORD	keyword to specify that record corresponds to a time-series file.
GWF	EVT	OPTIONS	FILEIN	KEYWORD	keyword to specify that an input filename is expected next.
GWF	EVT	OPTIONS	TS6_FILENAME	STRING	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.
GWF	EVT	OPTIONS	OBS6	KEYWORD	keyword to specify that record corresponds to an observations file.
GWF	EVT	OPTIONS	OBS6_FILENAME	STRING	name of input file to define observations for the Evapotranspiration package. See the ``Observation utility'' section for instructions for preparing observation input files. Tables \ref{table:gwf-obstypetable} and \ref{table:gwt-obstypetable} lists observation type(s) supported by the Evapotranspiration package.
GWF	EVT	OPTIONS	SURF_RATE_SPECIFIED	KEYWORD	indicates that the proportion of the evapotranspiration rate at the ET surface will be specified as PETM0 in list input.
GWF	EVT	DIMENSIONS	MAXBOUND	INTEGER	integer value specifying the maximum number of evapotranspiration cells cells that will be specified for use during any stress period.
GWF	EVT	DIMENSIONS	NSEG	INTEGER	number of ET segments. Default is one. When NSEG is greater than 1, the PXDP and PETM arrays must be of size NSEG - 1 and be listed in order from the uppermost segment down. Values for PXDP must be listed first followed by the values for PETM. PXDP defines the extinction-depth proportion at the bottom of a segment. PETM defines the proportion of the maximum ET flux rate at the bottom of a segment.
GWF	EVT	PERIOD	IPER	INTEGER	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.
GWF	EVT	PERIOD	CELLID	INTEGER (NCELLDIM)	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.
GWF	EVT	PERIOD	SURFACE	DOUBLE PRECISION	is the elevation of the ET surface ($L$). If the Options block includes a TIMESERIESFILE entry (see the ``Time-Variable Input'' section), values can be obtained from a time series by entering the time-series name in place of a numeric value.
GWF	EVT	PERIOD	RATE	DOUBLE PRECISION	is the maximum ET flux rate ($LT^{-1}$). If the Options block includes a TIMESERIESFILE entry (see the ``Time-Variable Input'' section), values can be obtained from a time series by entering the time-series name in place of a numeric value.
GWF	EVT	PERIOD	DEPTH	DOUBLE PRECISION	is the ET extinction depth ($L$). 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.
GWF	EVT	PERIOD	PXDP	DOUBLE PRECISION (NSEG-1)	is the proportion of the ET extinction depth at the bottom of a segment (dimensionless). pxdp is an array of size (nseg - 1). Values in pxdp must be greater than 0.0 and less than 1.0. pxdp values for a cell must increase monotonically. 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.
GWF	EVT	PERIOD	PETM	DOUBLE PRECISION (NSEG-1)	is the proportion of the maximum ET flux rate at the bottom of a segment (dimensionless). petm is an array of size (nseg - 1). 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.
GWF	EVT	PERIOD	PETM0	DOUBLE PRECISION	is the proportion of the maximum ET flux rate that will apply when head is at or above the ET surface (dimensionless). PETM0 is read only when the SURF_RATE_SPECIFIED option is used. 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.
GWF	EVT	PERIOD	AUX	DOUBLE PRECISION (NAUX)	represents the values of the auxiliary variables for each evapotranspiration. The values of auxiliary variables must be present for each evapotranspiration. 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.
GWF	EVT	PERIOD	BOUNDNAME	STRING	name of the evapotranspiration 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.
GWF	EVTA	OPTIONS	READASARRAYS	KEYWORD	indicates that array-based input will be used for the Evapotranspiration Package. This keyword must be specified to use array-based input.
GWF	EVTA	OPTIONS	FIXED_CELL	KEYWORD	indicates that evapotranspiration will not be reassigned to a cell underlying the cell specified in the list if the specified cell is inactive.
GWF	EVTA	OPTIONS	AUXILIARY	STRING (NAUX)	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.
GWF	EVTA	OPTIONS	AUXMULTNAME	STRING	name of auxiliary variable to be used as multiplier of evapotranspiration rate.
GWF	EVTA	OPTIONS	PRINT_INPUT	KEYWORD	keyword to indicate that the list of evapotranspiration information will be written to the listing file immediately after it is read.
GWF	EVTA	OPTIONS	PRINT_FLOWS	KEYWORD	keyword to indicate that the list of evapotranspiration 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.
GWF	EVTA	OPTIONS	SAVE_FLOWS	KEYWORD	keyword to indicate that evapotranspiration flow terms will be written to the file specified with ``BUDGET FILEOUT'' in Output Control.
GWF	EVTA	OPTIONS	TAS6	KEYWORD	keyword to specify that record corresponds to a time-array-series file.
GWF	EVTA	OPTIONS	FILEIN	KEYWORD	keyword to specify that an input filename is expected next.
GWF	EVTA	OPTIONS	TAS6_FILENAME	STRING	defines a time-array-series file defining a time-array series that can be used to assign time-varying values. See the Time-Variable Input section for instructions on using the time-array series capability.
GWF	EVTA	OPTIONS	OBS6	KEYWORD	keyword to specify that record corresponds to an observations file.
GWF	EVTA	OPTIONS	OBS6_FILENAME	STRING	name of input file to define observations for the Evapotranspiration package. See the ``Observation utility'' section for instructions for preparing observation input files. Tables \ref{table:gwf-obstypetable} and \ref{table:gwt-obstypetable} lists observation type(s) supported by the Evapotranspiration package.
GWF	EVTA	PERIOD	IPER	INTEGER	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.
GWF	EVTA	PERIOD	IEVT	INTEGER (NCOL*NROW; NCPL)	IEVT is the layer number that defines the layer in each vertical column where evapotranspiration is applied. If IEVT is omitted, evapotranspiration by default is applied to cells in layer 1. If IEVT is specified, it must be specified as the first variable in the PERIOD block or MODFLOW will terminate with an error.
GWF	EVTA	PERIOD	SURFACE	DOUBLE PRECISION (NCOL*NROW; NCPL)	is the elevation of the ET surface ($L$).
GWF	EVTA	PERIOD	RATE	DOUBLE PRECISION (NCOL*NROW; NCPL)	is the maximum ET flux rate ($LT^{-1}$).
GWF	EVTA	PERIOD	DEPTH	DOUBLE PRECISION (NCOL*NROW; NCPL)	is the ET extinction depth ($L$).
GWF	EVTA	PERIOD	AUX(IAUX)	DOUBLE PRECISION (NCOL*NROW; NCPL)	is an array of values for auxiliary variable AUX(IAUX), where iaux is a value from 1 to NAUX, and AUX(IAUX) must be listed as part of the auxiliary variables. A separate array can be specified for each auxiliary variable. If an array is not specified for an auxiliary variable, then a value of zero is assigned. If the value specified here for the auxiliary variable is the same as auxmultname, then the evapotranspiration rate will be multiplied by this array.
GWF	MAW	OPTIONS	AUXILIARY	STRING (NAUX)	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.
GWF	MAW	OPTIONS	BOUNDNAMES	KEYWORD	keyword to indicate that boundary names may be provided with the list of multi-aquifer well cells.
GWF	MAW	OPTIONS	PRINT_INPUT	KEYWORD	keyword to indicate that the list of multi-aquifer well information will be written to the listing file immediately after it is read.
GWF	MAW	OPTIONS	PRINT_HEAD	KEYWORD	keyword to indicate that the list of multi-aquifer well heads will be printed to the listing file for every stress period in which ``HEAD PRINT'' is specified in Output Control. If there is no Output Control option and PRINT_HEAD is specified, then heads are printed for the last time step of each stress period.
GWF	MAW	OPTIONS	PRINT_FLOWS	KEYWORD	keyword to indicate that the list of multi-aquifer well 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.
GWF	MAW	OPTIONS	SAVE_FLOWS	KEYWORD	keyword to indicate that multi-aquifer well flow terms will be written to the file specified with ``BUDGET FILEOUT'' in Output Control.
GWF	MAW	OPTIONS	HEAD	KEYWORD	keyword to specify that record corresponds to head.
GWF	MAW	OPTIONS	HEADFILE	STRING	name of the binary output file to write head information.
GWF	MAW	OPTIONS	BUDGET	KEYWORD	keyword to specify that record corresponds to the budget.
GWF	MAW	OPTIONS	FILEOUT	KEYWORD	keyword to specify that an output filename is expected next.
GWF	MAW	OPTIONS	BUDGETFILE	STRING	name of the binary output file to write budget information.
GWF	MAW	OPTIONS	BUDGETCSV	KEYWORD	keyword to specify that record corresponds to the budget CSV.
GWF	MAW	OPTIONS	BUDGETCSVFILE	STRING	name of the comma-separated value (CSV) output file to write budget summary information. A budget summary record will be written to this file for each time step of the simulation.
GWF	MAW	OPTIONS	NO_WELL_STORAGE	KEYWORD	keyword that deactivates inclusion of well storage contributions to the multi-aquifer well package continuity equation.
GWF	MAW	OPTIONS	FLOW_CORRECTION	KEYWORD	keyword that activates flow corrections in cases where the head in a multi-aquifer well is below the bottom of the screen for a connection or the head in a convertible cell connected to a multi-aquifer well is below the cell bottom. When flow corrections are activated, unit head gradients are used to calculate the flow between a multi-aquifer well and a connected GWF cell. By default, flow corrections are not made.
GWF	MAW	OPTIONS	FLOWING_WELLS	KEYWORD	keyword that activates the flowing wells option for the multi-aquifer well package.
GWF	MAW	OPTIONS	SHUTDOWN_THETA	DOUBLE PRECISION	value that defines the weight applied to discharge rate for wells that limit the water level in a discharging well (defined using the HEAD_LIMIT keyword in the stress period data). SHUTDOWN_THETA is used to control discharge rate oscillations when the flow rate from the aquifer is less than the specified flow rate from the aquifer to the well. Values range between 0.0 and 1.0, and larger values increase the weight (decrease under-relaxation) applied to the well discharge rate. The HEAD_LIMIT option has been included to facilitate backward compatibility with previous versions of MODFLOW but use of the RATE_SCALING option instead of the HEAD_LIMIT option is recommended. By default, SHUTDOWN_THETA is 0.7.
GWF	MAW	OPTIONS	SHUTDOWN_KAPPA	DOUBLE PRECISION	value that defines the weight applied to discharge rate for wells that limit the water level in a discharging well (defined using the HEAD_LIMIT keyword in the stress period data). SHUTDOWN_KAPPA is used to control discharge rate oscillations when the flow rate from the aquifer is less than the specified flow rate from the aquifer to the well. Values range between 0.0 and 1.0, and larger values increase the weight applied to the well discharge rate. The HEAD_LIMIT option has been included to facilitate backward compatibility with previous versions of MODFLOW but use of the RATE_SCALING option instead of the HEAD_LIMIT option is recommended. By default, SHUTDOWN_KAPPA is 0.0001.
GWF	MAW	OPTIONS	MAW_FLOW_REDUCE_CSV	KEYWORD	keyword to specify that record corresponds to the output option in which a new record is written for each multi-aquifer well and for each time step in which the user-requested extraction or injection rate is reduced by the program.
GWF	MAW	OPTIONS	MFRCSVFILE	STRING	name of the comma-separated value (CSV) output file to write information about multi-aquifer well extraction or injection rates that have been reduced by the program. Entries are only written if the extraction or injection rates are reduced.
GWF	MAW	OPTIONS	TS6	KEYWORD	keyword to specify that record corresponds to a time-series file.
GWF	MAW	OPTIONS	FILEIN	KEYWORD	keyword to specify that an input filename is expected next.
GWF	MAW	OPTIONS	TS6_FILENAME	STRING	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.
GWF	MAW	OPTIONS	OBS6	KEYWORD	keyword to specify that record corresponds to an observations file.
GWF	MAW	OPTIONS	OBS6_FILENAME	STRING	name of input file to define observations for the MAW package. See the ``Observation utility'' section for instructions for preparing observation input files. Tables \ref{table:gwf-obstypetable} and \ref{table:gwt-obstypetable} lists observation type(s) supported by the MAW package.
GWF	MAW	OPTIONS	MOVER	KEYWORD	keyword to indicate that this instance of the MAW Package can be used with the Water Mover (MVR) Package. When the MOVER option is specified, additional memory is allocated within the package to store the available, provided, and received water.
GWF	MAW	DIMENSIONS	NMAWWELLS	INTEGER	integer value specifying the number of multi-aquifer wells that will be simulated for all stress periods.
GWF	MAW	PACKAGEDATA	IFNO	INTEGER	integer value that defines the feature (well) number associated with the specified PACKAGEDATA data on the line. IFNO must be greater than zero and less than or equal to NMAWWELLS. Multi-aquifer well information must be specified for every multi-aquifer well or the program will terminate with an error. The program will also terminate with an error if information for a multi-aquifer well is specified more than once.
GWF	MAW	PACKAGEDATA	RADIUS	DOUBLE PRECISION	radius for the multi-aquifer well. The program will terminate with an error if the radius is less than or equal to zero.
GWF	MAW	PACKAGEDATA	BOTTOM	DOUBLE PRECISION	bottom elevation of the multi-aquifer well. If CONDEQN is SPECIFIED, THIEM, SKIN, or COMPOSITE, BOTTOM is set to the cell bottom in the lowermost GWF cell connection in cases where the specified well bottom is above the bottom of this GWF cell. If CONDEQN is MEAN, BOTTOM is set to the lowermost GWF cell connection screen bottom in cases where the specified well bottom is above this value. The bottom elevation defines the lowest well head that will be simulated when the NEWTON UNDER_RELAXATION option is specified in the GWF model name file. The bottom elevation is also used to calculate volumetric storage in the well.
GWF	MAW	PACKAGEDATA	STRT	DOUBLE PRECISION	starting head for the multi-aquifer well. The program will terminate with an error if the starting head is less than the specified well bottom.
GWF	MAW	PACKAGEDATA	CONDEQN	STRING	character string that defines the conductance equation that is used to calculate the saturated conductance for the multi-aquifer well. Possible multi-aquifer well CONDEQN strings include: SPECIFIED--character keyword to indicate the multi-aquifer well saturated conductance will be specified. THIEM--character keyword to indicate the multi-aquifer well saturated conductance will be calculated using the Thiem equation, which considers the cell top and bottom, aquifer hydraulic conductivity, and effective cell and well radius. SKIN--character keyword to indicate that the multi-aquifer well saturated conductance will be calculated using the cell top and bottom, aquifer and screen hydraulic conductivity, and well and skin radius. CUMULATIVE--character keyword to indicate that the multi-aquifer well saturated conductance will be calculated using a combination of the Thiem and SKIN equations. MEAN--character keyword to indicate the multi-aquifer well saturated conductance will be calculated using the aquifer and screen top and bottom, aquifer and screen hydraulic conductivity, and well and skin radius. The CUMULATIVE conductance equation is identical to the SKIN LOSSTYPE in the Multi-Node Well (MNW2) package for MODFLOW-2005. The program will terminate with an error condition if CONDEQN is SKIN or CUMULATIVE and the calculated saturated conductance is less than zero; if an error condition occurs, it is suggested that the THEIM or MEAN conductance equations be used for these multi-aquifer wells.
GWF	MAW	PACKAGEDATA	NGWFNODES	INTEGER	integer value that defines the number of GWF nodes connected to this (IFNO) multi-aquifer well. NGWFNODES must be greater than zero.
GWF	MAW	PACKAGEDATA	AUX	DOUBLE PRECISION (NAUX)	represents the values of the auxiliary variables for each multi-aquifer well. The values of auxiliary variables must be present for each multi-aquifer well. 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.
GWF	MAW	PACKAGEDATA	BOUNDNAME	STRING	name of the multi-aquifer well 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.
GWF	MAW	CONNECTIONDATA	IFNO	INTEGER	integer value that defines the feature (well) number associated with the specified CONNECTIONDATA data on the line. IFNO must be greater than zero and less than or equal to NMAWWELLS. Multi-aquifer well connection information must be specified for every multi-aquifer well connection to the GWF model (NGWFNODES) or the program will terminate with an error. The program will also terminate with an error if connection information for a multi-aquifer well connection to the GWF model is specified more than once.
GWF	MAW	CONNECTIONDATA	ICON	INTEGER	integer value that defines the GWF connection number for this multi-aquifer well connection entry. ICONN must be greater than zero and less than or equal to NGWFNODES for multi-aquifer well IFNO.
GWF	MAW	CONNECTIONDATA	CELLID	INTEGER (NCELLDIM)	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. One or more screened intervals can be connected to the same CELLID if CONDEQN for a well is MEAN. The program will terminate with an error if MAW wells using SPECIFIED, THIEM, SKIN, or CUMULATIVE conductance equations have more than one connection to the same CELLID.
GWF	MAW	CONNECTIONDATA	SCRN_TOP	DOUBLE PRECISION	value that defines the top elevation of the screen for the multi-aquifer well connection. If CONDEQN is SPECIFIED, THIEM, SKIN, or COMPOSITE, SCRN_TOP can be any value and is set to the top of the cell. If CONDEQN is MEAN, SCRN_TOP is set to the multi-aquifer well connection cell top if the specified value is greater than the cell top. The program will terminate with an error if the screen top is less than the screen bottom.
GWF	MAW	CONNECTIONDATA	SCRN_BOT	DOUBLE PRECISION	value that defines the bottom elevation of the screen for the multi-aquifer well connection. If CONDEQN is SPECIFIED, THIEM, SKIN, or COMPOSITE, SCRN_BOT can be any value is set to the bottom of the cell. If CONDEQN is MEAN, SCRN_BOT is set to the multi-aquifer well connection cell bottom if the specified value is less than the cell bottom. The program will terminate with an error if the screen bottom is greater than the screen top.
GWF	MAW	CONNECTIONDATA	HK_SKIN	DOUBLE PRECISION	value that defines the skin (filter pack) hydraulic conductivity (if CONDEQN for the multi-aquifer well is SKIN, CUMULATIVE, or MEAN) or conductance (if CONDEQN for the multi-aquifer well is SPECIFIED) for each GWF node connected to the multi-aquifer well (NGWFNODES). If CONDEQN is SPECIFIED, HK_SKIN must be greater than or equal to zero. HK_SKIN can be any value if CONDEQN is THIEM. Otherwise, HK_SKIN must be greater than zero. If CONDEQN is SKIN, the contrast between the cell transmissivity (the product of geometric mean horizontal hydraulic conductivity and the cell thickness) and the well transmissivity (the product of HK_SKIN and the screen thicknesses) must be greater than one in node CELLID or the program will terminate with an error condition; if an error condition occurs, it is suggested that the HK_SKIN be reduced to a value less than K11 and K22 in node CELLID or the THEIM or MEAN conductance equations be used for these multi-aquifer wells.
GWF	MAW	CONNECTIONDATA	RADIUS_SKIN	DOUBLE PRECISION	real value that defines the skin radius (filter pack radius) for the multi-aquifer well. RADIUS_SKIN can be any value if CONDEQN is SPECIFIED or THIEM. If CONDEQN is SKIN, CUMULATIVE, or MEAN, the program will terminate with an error if RADIUS_SKIN is less than or equal to the RADIUS for the multi-aquifer well.
GWF	MAW	PERIOD	IPER	INTEGER	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.
GWF	MAW	PERIOD	IFNO	INTEGER	integer value that defines the well number associated with the specified PERIOD data on the line. IFNO must be greater than zero and less than or equal to NMAWWELLS.
GWF	MAW	PERIOD	MAWSETTING	KEYSTRING	line of information that is parsed into a keyword and values. Keyword values that can be used to start the MAWSETTING string include: STATUS, FLOWING_WELL, RATE, WELL_HEAD, HEAD_LIMIT, SHUT_OFF, RATE_SCALING, and AUXILIARY.
GWF	MAW	PERIOD	STATUS	STRING	keyword option to define well status. STATUS can be ACTIVE, INACTIVE, or CONSTANT. By default, STATUS is ACTIVE.
GWF	MAW	PERIOD	FLOWING_WELL	KEYWORD	keyword to indicate the well is a flowing well. The FLOWING_WELL option can be used to simulate flowing wells when the simulated well head exceeds the specified drainage elevation.
GWF	MAW	PERIOD	FWELEV	DOUBLE PRECISION	elevation used to determine whether or not the well is flowing.
GWF	MAW	PERIOD	FWCOND	DOUBLE PRECISION	conductance used to calculate the discharge of a free flowing well. Flow occurs when the head in the well is above the well top elevation (FWELEV).
GWF	MAW	PERIOD	FWRLEN	DOUBLE PRECISION	length used to reduce the conductance of the flowing well. When the head in the well drops below the well top plus the reduction length, then the conductance is reduced. This reduction length can be used to improve the stability of simulations with flowing wells so that there is not an abrupt change in flowing well rates.
GWF	MAW	PERIOD	RATE	DOUBLE PRECISION	is the volumetric pumping rate for the multi-aquifer well. A positive value indicates recharge and a negative value indicates discharge (pumping). RATE only applies to active (STATUS is ACTIVE) multi-aquifer wells. 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. By default, the RATE for each multi-aquifer well is zero.
GWF	MAW	PERIOD	WELL_HEAD	DOUBLE PRECISION	is the head in the multi-aquifer well. WELL_HEAD is only applied to constant head (STATUS is CONSTANT) and inactive (STATUS is INACTIVE) multi-aquifer wells. 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. The program will terminate with an error if WELL_HEAD is less than the bottom of the well.
GWF	MAW	PERIOD	HEAD_LIMIT	STRING	is the limiting water level (head) in the well, which is the minimum of the well RATE or the well inflow rate from the aquifer. HEAD_LIMIT can be applied to extraction wells (RATE $&lt;$ 0) or injection wells (RATE $&gt;$ 0). HEAD_LIMIT can be deactivated by specifying the text string OFF'. The HEAD\_LIMIT option is based on the HEAD\_LIMIT functionality available in the MNW2~\citep{konikow2009} package for MODFLOW-2005. The HEAD\_LIMIT option has been included to facilitate backward compatibility with previous versions of MODFLOW but use of the RATE\_SCALING option instead of the HEAD\_LIMIT option is recommended. By default, HEAD\_LIMIT is OFF'.
GWF	MAW	PERIOD	SHUT_OFF	KEYWORD	keyword for activating well shut off capability. Subsequent values define the minimum and maximum pumping rate that a well must exceed to shutoff or reactivate a well, respectively, during a stress period. SHUT_OFF is only applied to injection wells (RATE$<0$) and if HEAD_LIMIT is specified (not set to `OFF'). If HEAD_LIMIT is specified, SHUT_OFF can be deactivated by specifying a minimum value equal to zero. The SHUT_OFF option is based on the SHUT_OFF functionality available in the MNW2~\citep{konikow2009} package for MODFLOW-2005. The SHUT_OFF option has been included to facilitate backward compatibility with previous versions of MODFLOW but use of the RATE_SCALING option instead of the SHUT_OFF option is recommended. By default, SHUT_OFF is not used.
GWF	MAW	PERIOD	MINRATE	DOUBLE PRECISION	is the minimum rate that a well must exceed to shutoff a well during a stress period. The well will shut down during a time step if the flow rate to the well from the aquifer is less than MINRATE. If a well is shut down during a time step, reactivation of the well cannot occur until the next time step to reduce oscillations. MINRATE must be less than maxrate.
GWF	MAW	PERIOD	MAXRATE	DOUBLE PRECISION	is the maximum rate that a well must exceed to reactivate a well during a stress period. The well will reactivate during a timestep if the well was shutdown during the previous time step and the flow rate to the well from the aquifer exceeds maxrate. Reactivation of the well cannot occur until the next time step if a well is shutdown to reduce oscillations. maxrate must be greater than MINRATE.
GWF	MAW	PERIOD	RATE_SCALING	KEYWORD	activate rate scaling. If RATE_SCALING is specified, both PUMP_ELEVATION and SCALING_LENGTH must be specified. RATE_SCALING cannot be used with HEAD_LIMIT. RATE_SCALING can be used for extraction or injection wells. For extraction wells, the extraction rate will start to decrease once the head in the well lowers to a level equal to the pump elevation plus the scaling length. If the head in the well drops below the pump elevation, then the extraction rate is calculated to be zero. For an injection well, the injection rate will begin to decrease once the head in the well rises above the specified pump elevation. If the head in the well rises above the pump elevation plus the scaling length, then the injection rate will be set to zero.
GWF	MAW	PERIOD	PUMP_ELEVATION	DOUBLE PRECISION	is the elevation of the multi-aquifer well pump (PUMP_ELEVATION). PUMP_ELEVATION should not be less than the bottom elevation (BOTTOM) of the multi-aquifer well.
GWF	MAW	PERIOD	SCALING_LENGTH	DOUBLE PRECISION	height above the pump elevation (SCALING_LENGTH). If the simulated well head is below this elevation (pump elevation plus the scaling length), then the pumping rate is reduced.
GWF	MAW	PERIOD	AUXILIARY	KEYWORD	keyword for specifying auxiliary variable.
GWF	MAW	PERIOD	AUXNAME	STRING	name for the auxiliary variable to be assigned AUXVAL. AUXNAME must match one of the auxiliary variable names defined in the OPTIONS block. If AUXNAME does not match one of the auxiliary variable names defined in the OPTIONS block the data are ignored.
GWF	MAW	PERIOD	AUXVAL	DOUBLE PRECISION	value for the auxiliary variable. 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.
GWF	SFR	OPTIONS	AUXILIARY	STRING (NAUX)	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.
GWF	SFR	OPTIONS	BOUNDNAMES	KEYWORD	keyword to indicate that boundary names may be provided with the list of stream reach cells.
GWF	SFR	OPTIONS	PRINT_INPUT	KEYWORD	keyword to indicate that the list of stream reach information will be written to the listing file immediately after it is read.
GWF	SFR	OPTIONS	PRINT_STAGE	KEYWORD	keyword to indicate that the list of stream reach stages will be printed to the listing file for every stress period in which ``HEAD PRINT'' is specified in Output Control. If there is no Output Control option and PRINT_STAGE is specified, then stages are printed for the last time step of each stress period.
GWF	SFR	OPTIONS	PRINT_FLOWS	KEYWORD	keyword to indicate that the list of stream reach 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.
GWF	SFR	OPTIONS	SAVE_FLOWS	KEYWORD	keyword to indicate that stream reach flow terms will be written to the file specified with ``BUDGET FILEOUT'' in Output Control.
GWF	SFR	OPTIONS	STAGE	KEYWORD	keyword to specify that record corresponds to stage.
GWF	SFR	OPTIONS	STAGEFILE	STRING	name of the binary output file to write stage information.
GWF	SFR	OPTIONS	BUDGET	KEYWORD	keyword to specify that record corresponds to the budget.
GWF	SFR	OPTIONS	FILEOUT	KEYWORD	keyword to specify that an output filename is expected next.
GWF	SFR	OPTIONS	BUDGETFILE	STRING	name of the binary output file to write budget information.
GWF	SFR	OPTIONS	BUDGETCSV	KEYWORD	keyword to specify that record corresponds to the budget CSV.
GWF	SFR	OPTIONS	BUDGETCSVFILE	STRING	name of the comma-separated value (CSV) output file to write budget summary information. A budget summary record will be written to this file for each time step of the simulation.
GWF	SFR	OPTIONS	PACKAGE_CONVERGENCE	KEYWORD	keyword to specify that record corresponds to the package convergence comma spaced values file.
GWF	SFR	OPTIONS	PACKAGE_CONVERGENCE_FILENAME	STRING	name of the comma spaced values output file to write package convergence information.
GWF	SFR	OPTIONS	TS6	KEYWORD	keyword to specify that record corresponds to a time-series file.
GWF	SFR	OPTIONS	FILEIN	KEYWORD	keyword to specify that an input filename is expected next.
GWF	SFR	OPTIONS	TS6_FILENAME	STRING	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.
GWF	SFR	OPTIONS	OBS6	KEYWORD	keyword to specify that record corresponds to an observations file.
GWF	SFR	OPTIONS	OBS6_FILENAME	STRING	name of input file to define observations for the SFR package. See the ``Observation utility'' section for instructions for preparing observation input files. Tables \ref{table:gwf-obstypetable} and \ref{table:gwt-obstypetable} lists observation type(s) supported by the SFR package.
GWF	SFR	OPTIONS	MOVER	KEYWORD	keyword to indicate that this instance of the SFR Package can be used with the Water Mover (MVR) Package. When the MOVER option is specified, additional memory is allocated within the package to store the available, provided, and received water.
GWF	SFR	OPTIONS	MAXIMUM_PICARD_ITERATIONS	INTEGER	integer value that defines the maximum number of Streamflow Routing picard iterations allowed when solving for reach stages and flows as part of the GWF formulate step. Picard iterations are used to minimize differences in SFR package results between subsequent GWF picard (non-linear) iterations as a result of non-optimal reach numbering. If reaches are numbered in order, from upstream to downstream, MAXIMUM_PICARD_ITERATIONS can be set to 1 to reduce model run time. By default, MAXIMUM_PICARD_ITERATIONS is equal to 100.
GWF	SFR	OPTIONS	MAXIMUM_ITERATIONS	INTEGER	integer value that defines the maximum number of Streamflow Routing Newton-Raphson iterations allowed for a reach. By default, MAXIMUM_ITERATIONS is equal to 100. MAXIMUM_ITERATIONS would only need to be increased from the default value if one or more reach in a simulation has a large water budget error.
GWF	SFR	OPTIONS	MAXIMUM_DEPTH_CHANGE	DOUBLE PRECISION	real value that defines the depth closure tolerance. By default, MAXIMUM_DEPTH_CHANGE is equal to $1 \times 10^{-5}$. The MAXIMUM_STAGE_CHANGE would only need to be increased or decreased from the default value if the water budget error for one or more reach is too small or too large, respectively.
GWF	SFR	OPTIONS	UNIT_CONVERSION	DOUBLE PRECISION	real value that is used to convert user-specified Manning's roughness coefficients from seconds per meters$^{1/3}$ to model length and time units. A constant of 1.486 is used for flow units of cubic feet per second, and a constant of 1.0 is used for units of cubic meters per second. The constant must be multiplied by 86,400 when using time units of days in the simulation.
GWF	SFR	OPTIONS	LENGTH_CONVERSION	DOUBLE PRECISION	real value that is used to convert user-specified Manning's roughness coefficients from meters to model length units. LENGTH_CONVERSION should be set to 3.28081, 1.0, and 100.0 when using length units (LENGTH_UNITS) of feet, meters, or centimeters in the simulation, respectively. LENGTH_CONVERSION does not need to be specified if LENGTH_UNITS are meters.
GWF	SFR	OPTIONS	TIME_CONVERSION	DOUBLE PRECISION	real value that is used to convert user-specified Manning's roughness coefficients from seconds to model time units. TIME_CONVERSION should be set to 1.0, 60.0, 3,600.0, 86,400.0, and 31,557,600.0 when using time units (TIME_UNITS) of seconds, minutes, hours, days, or years in the simulation, respectively. TIME_CONVERSION does not need to be specified if TIME_UNITS are seconds.
GWF	SFR	DIMENSIONS	NREACHES	INTEGER	integer value specifying the number of stream reaches. There must be NREACHES entries in the PACKAGEDATA block.
GWF	SFR	PACKAGEDATA	IFNO	INTEGER	integer value that defines the feature (reach) number associated with the specified PACKAGEDATA data on the line. IFNO must be greater than zero and less than or equal to NREACHES. Reach information must be specified for every reach or the program will terminate with an error. The program will also terminate with an error if information for a reach is specified more than once.
GWF	SFR	PACKAGEDATA	CELLID	INTEGER (NCELLDIM)	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. For reaches that are not connected to an underlying GWF cell, a zero should be specified for each grid dimension. For example, for a DIS grid a CELLID of 0 0 0 should be specified. Reach-aquifer flow is not calculated for unconnected reaches. The keyword NONE can be still be specified to identify unconnected reaches for backward compatibility with previous versions of MODFLOW 6 but eventually NONE will be deprecated and will cause MODFLOW 6 to terminate with an error.
GWF	SFR	PACKAGEDATA	RLEN	DOUBLE PRECISION	real value that defines the reach length. RLEN must be greater than zero.
GWF	SFR	PACKAGEDATA	RWID	DOUBLE PRECISION	real value that defines the reach width. RWID must be greater than zero.
GWF	SFR	PACKAGEDATA	RGRD	DOUBLE PRECISION	real value that defines the stream gradient (slope) across the reach. RGRD must be greater than zero.
GWF	SFR	PACKAGEDATA	RTP	DOUBLE PRECISION	real value that defines the bottom elevation of the reach.
GWF	SFR	PACKAGEDATA	RBTH	DOUBLE PRECISION	real value that defines the thickness of the reach streambed. RBTH can be any value if the reach is not connected to an underlying GWF cell. Otherwise, RBTH must be greater than zero.
GWF	SFR	PACKAGEDATA	RHK	DOUBLE PRECISION	real value that defines the hydraulic conductivity of the reach streambed. RHK can be any positive value if the reach is not connected to an underlying GWF cell. Otherwise, RHK must be greater than zero.
GWF	SFR	PACKAGEDATA	MAN	STRING	real or character value that defines the Manning's roughness coefficient for the reach. MAN must be greater than zero. 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.
GWF	SFR	PACKAGEDATA	NCON	INTEGER	integer value that defines the number of reaches connected to the reach. If a value of zero is specified for NCON an entry for IFNO is still required in the subsequent CONNECTIONDATA block.
GWF	SFR	PACKAGEDATA	USTRF	DOUBLE PRECISION	real value that defines the fraction of upstream flow from each upstream reach that is applied as upstream inflow to the reach. The sum of all USTRF values for all reaches connected to the same upstream reach must be equal to one and USTRF must be greater than or equal to zero. 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.
GWF	SFR	PACKAGEDATA	NDV	INTEGER	integer value that defines the number of downstream diversions for the reach.
GWF	SFR	PACKAGEDATA	AUX	DOUBLE PRECISION (NAUX)	represents the values of the auxiliary variables for each stream reach. The values of auxiliary variables must be present for each stream reach. 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.
GWF	SFR	PACKAGEDATA	BOUNDNAME	STRING	name of the stream reach 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.
GWF	SFR	CROSSSECTIONS	IFNO	INTEGER	integer value that defines the feature (reach) number associated with the specified cross-section table file on the line. IFNO must be greater than zero and less than or equal to NREACHES. The program will also terminate with an error if table information for a reach is specified more than once.
GWF	SFR	CROSSSECTIONS	TAB6	KEYWORD	keyword to specify that record corresponds to a cross-section table file.
GWF	SFR	CROSSSECTIONS	FILEIN	KEYWORD	keyword to specify that an input filename is expected next.
GWF	SFR	CROSSSECTIONS	TAB6_FILENAME	STRING	character string that defines the path and filename for the file containing cross-section table data for the reach. The TAB6_FILENAME file includes the number of entries in the file and the station elevation data in terms of the fractional width and the reach depth. Instructions for creating the TAB6_FILENAME input file are provided in SFR Reach Cross-Section Table Input File section.
GWF	SFR	CONNECTIONDATA	IFNO	INTEGER	integer value that defines the feature (reach) number associated with the specified CONNECTIONDATA data on the line. IFNO must be greater than zero and less than or equal to NREACHES. Reach connection information must be specified for every reach or the program will terminate with an error. The program will also terminate with an error if connection information for a reach is specified more than once.
GWF	SFR	CONNECTIONDATA	IC	INTEGER (NCON(IFNO))	integer value that defines the reach number of the reach connected to the current reach and whether it is connected to the upstream or downstream end of the reach. Negative IC numbers indicate connected reaches are connected to the downstream end of the current reach. Positive IC numbers indicate connected reaches are connected to the upstream end of the current reach. The absolute value of IC must be greater than zero and less than or equal to NREACHES. IC should not be specified when NCON is zero but must be specified otherwise.
GWF	SFR	DIVERSIONS	IFNO	INTEGER	integer value that defines the feature (reach) number associated with the specified DIVERSIONS data on the line. IFNO must be greater than zero and less than or equal to NREACHES. Reach diversion information must be specified for every reach with a NDV value greater than 0 or the program will terminate with an error. The program will also terminate with an error if diversion information for a given reach diversion is specified more than once.
GWF	SFR	DIVERSIONS	IDV	INTEGER	integer value that defines the downstream diversion number for the diversion for reach IFNO. IDV must be greater than zero and less than or equal to NDV for reach IFNO.
GWF	SFR	DIVERSIONS	ICONR	INTEGER	integer value that defines the downstream reach that will receive the diverted water. IDV must be greater than zero and less than or equal to NREACHES. Furthermore, reach ICONR must be a downstream connection for reach IFNO.
GWF	SFR	DIVERSIONS	CPRIOR	STRING	character string value that defines the the prioritization system for the diversion, such as when insufficient water is available to meet all diversion stipulations, and is used in conjunction with the value of FLOW value specified in the STRESS_PERIOD_DATA section. Available diversion options include: (1) CPRIOR = FRACTION', then the amount of the diversion is computed as a fraction of the streamflow leaving reach IFNO ($Q_{DS}$); in this case, 0.0 $\le$ DIVFLOW $\le$ 1.0. (2) CPRIOR = EXCESS', a diversion is made only if $Q_{DS}$ for reach IFNO exceeds the value of DIVFLOW. If this occurs, then the quantity of water diverted is the excess flow ($Q_{DS} -$ DIVFLOW) and $Q_{DS}$ from reach IFNO is set equal to DIVFLOW. This represents a flood-control type of diversion, as described by Danskin and Hanson (2002). (3) CPRIOR = THRESHOLD', then if $Q_{DS}$ in reach IFNO is less than the specified diversion flow DIVFLOW, no water is diverted from reach IFNO. If $Q_{DS}$ in reach IFNO is greater than or equal to DIVFLOW, DIVFLOW is diverted and $Q_{DS}$ is set to the remainder ($Q_{DS} -$ DIVFLOW)). This approach assumes that once flow in the stream is sufficiently low, diversions from the stream cease, and is the priority' algorithm that originally was programmed into the STR1 Package (Prudic, 1989). (4) CPRIOR = `UPTO' -- if $Q_{DS}$ in reach IFNO is greater than or equal to the specified diversion flow DIVFLOW, $Q_{DS}$ is reduced by DIVFLOW. If $Q_{DS}$ in reach IFNO is less than DIVFLOW, DIVFLOW is set to $Q_{DS}$ and there will be no flow available for reaches connected to downstream end of reach IFNO.
GWF	SFR	PERIOD	IPER	INTEGER	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.
GWF	SFR	PERIOD	IFNO	INTEGER	integer value that defines the feature (reach) number associated with the specified PERIOD data on the line. IFNO must be greater than zero and less than or equal to NREACHES.
GWF	SFR	PERIOD	SFRSETTING	KEYSTRING	line of information that is parsed into a keyword and values. Keyword values that can be used to start the SFRSETTING string include: STATUS, MANNING, STAGE, INFLOW, RAINFALL, EVAPORATION, RUNOFF, DIVERSION, UPSTREAM_FRACTION, and AUXILIARY.
GWF	SFR	PERIOD	STATUS	STRING	keyword option to define stream reach status. STATUS can be ACTIVE, INACTIVE, or SIMPLE. The SIMPLE STATUS option simulates streamflow using a user-specified stage for a reach or a stage set to the top of the reach (depth = 0). In cases where the simulated leakage calculated using the specified stage exceeds the sum of inflows to the reach, the stage is set to the top of the reach and leakage is set equal to the sum of inflows. Upstream fractions should be changed using the UPSTREAM_FRACTION SFRSETTING if the status for one or more reaches is changed to ACTIVE or INACTIVE. For example, if one of two downstream connections for a reach is inactivated, the upstream fraction for the active and inactive downstream reach should be changed to 1.0 and 0.0, respectively, to ensure that the active reach receives all of the downstream outflow from the upstream reach. By default, STATUS is ACTIVE.
GWF	SFR	PERIOD	MANNING	STRING	real or character value that defines the Manning's roughness coefficient for the reach. MANNING must be greater than zero. 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.
GWF	SFR	PERIOD	STAGE	STRING	real or character value that defines the stage for the reach. The specified STAGE is only applied if the reach uses the simple routing option. If STAGE is not specified for reaches that use the simple routing option, the specified stage is set to the top of the reach. 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.
GWF	SFR	PERIOD	INFLOW	STRING	real or character value that defines the volumetric inflow rate for the streamflow routing reach. 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. By default, inflow rates are zero for each reach.
GWF	SFR	PERIOD	RAINFALL	STRING	real or character value that defines the volumetric rate per unit area of water added by precipitation directly on the streamflow routing reach. 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. By default, rainfall rates are zero for each reach.
GWF	SFR	PERIOD	EVAPORATION	STRING	real or character value that defines the volumetric rate per unit area of water subtracted by evaporation from the streamflow routing reach. A positive evaporation rate should be provided. 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. If the volumetric evaporation rate for a reach exceeds the sources of water to the reach (upstream and specified inflows, rainfall, and runoff but excluding groundwater leakage into the reach) the volumetric evaporation rate is limited to the sources of water to the reach. By default, evaporation rates are zero for each reach.
GWF	SFR	PERIOD	RUNOFF	STRING	real or character value that defines the volumetric rate of diffuse overland runoff that enters the streamflow routing reach. 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. If the volumetric runoff rate for a reach is negative and exceeds inflows to the reach (upstream and specified inflows, and rainfall but excluding groundwater leakage into the reach) the volumetric runoff rate is limited to inflows to the reach and the volumetric evaporation rate for the reach is set to zero. By default, runoff rates are zero for each reach.
GWF	SFR	PERIOD	DIVERSION	KEYWORD	keyword to indicate diversion record.
GWF	SFR	PERIOD	IDV	INTEGER	an integer value specifying which diversion of reach IFNO that DIVFLOW is being specified for. Must be less or equal to ndv for the current reach (IFNO).
GWF	SFR	PERIOD	DIVFLOW	DOUBLE PRECISION	real or character value that defines the volumetric diversion (DIVFLOW) rate for the streamflow routing reach. 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.
GWF	SFR	PERIOD	UPSTREAM_FRACTION	DOUBLE PRECISION	real value that defines the fraction of upstream flow (USTRF) from each upstream reach that is applied as upstream inflow to the reach. The sum of all USTRF values for all reaches connected to the same upstream reach must be equal to one.
GWF	SFR	PERIOD	CROSS_SECTION	KEYWORD	keyword to specify that record corresponds to a reach cross-section.
GWF	SFR	PERIOD	TAB6	KEYWORD	keyword to specify that record corresponds to a cross-section table file.
GWF	SFR	PERIOD	FILEIN	KEYWORD	keyword to specify that an input filename is expected next.
GWF	SFR	PERIOD	TAB6_FILENAME	STRING	character string that defines the path and filename for the file containing cross-section table data for the reach. The TAB6_FILENAME file includes the number of entries in the file and the station elevation data in terms of the fractional width and the reach depth. Instructions for creating the TAB6_FILENAME input file are provided in SFR Reach Cross-Section Table Input File section.
GWF	SFR	PERIOD	AUXILIARY	KEYWORD	keyword for specifying auxiliary variable.
GWF	SFR	PERIOD	AUXNAME	STRING	name for the auxiliary variable to be assigned AUXVAL. AUXNAME must match one of the auxiliary variable names defined in the OPTIONS block. If AUXNAME does not match one of the auxiliary variable names defined in the OPTIONS block the data are ignored.
GWF	SFR	PERIOD	AUXVAL	DOUBLE PRECISION	value for the auxiliary variable. 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.
GWF	LAK	OPTIONS	AUXILIARY	STRING (NAUX)	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.
GWF	LAK	OPTIONS	BOUNDNAMES	KEYWORD	keyword to indicate that boundary names may be provided with the list of lake cells.
GWF	LAK	OPTIONS	PRINT_INPUT	KEYWORD	keyword to indicate that the list of lake information will be written to the listing file immediately after it is read.
GWF	LAK	OPTIONS	PRINT_STAGE	KEYWORD	keyword to indicate that the list of lake stages will be printed to the listing file for every stress period in which ``HEAD PRINT'' is specified in Output Control. If there is no Output Control option and PRINT_STAGE is specified, then stages are printed for the last time step of each stress period.
GWF	LAK	OPTIONS	PRINT_FLOWS	KEYWORD	keyword to indicate that the list of lake 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.
GWF	LAK	OPTIONS	SAVE_FLOWS	KEYWORD	keyword to indicate that lake flow terms will be written to the file specified with ``BUDGET FILEOUT'' in Output Control.
GWF	LAK	OPTIONS	STAGE	KEYWORD	keyword to specify that record corresponds to stage.
GWF	LAK	OPTIONS	STAGEFILE	STRING	name of the binary output file to write stage information.
GWF	LAK	OPTIONS	BUDGET	KEYWORD	keyword to specify that record corresponds to the budget.
GWF	LAK	OPTIONS	FILEOUT	KEYWORD	keyword to specify that an output filename is expected next.
GWF	LAK	OPTIONS	BUDGETFILE	STRING	name of the binary output file to write budget information.
GWF	LAK	OPTIONS	BUDGETCSV	KEYWORD	keyword to specify that record corresponds to the budget CSV.
GWF	LAK	OPTIONS	BUDGETCSVFILE	STRING	name of the comma-separated value (CSV) output file to write budget summary information. A budget summary record will be written to this file for each time step of the simulation.
GWF	LAK	OPTIONS	PACKAGE_CONVERGENCE	KEYWORD	keyword to specify that record corresponds to the package convergence comma spaced values file.
GWF	LAK	OPTIONS	PACKAGE_CONVERGENCE_FILENAME	STRING	name of the comma spaced values output file to write package convergence information.
GWF	LAK	OPTIONS	TS6	KEYWORD	keyword to specify that record corresponds to a time-series file.
GWF	LAK	OPTIONS	FILEIN	KEYWORD	keyword to specify that an input filename is expected next.
GWF	LAK	OPTIONS	TS6_FILENAME	STRING	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.
GWF	LAK	OPTIONS	OBS6	KEYWORD	keyword to specify that record corresponds to an observations file.
GWF	LAK	OPTIONS	OBS6_FILENAME	STRING	name of input file to define observations for the LAK package. See the ``Observation utility'' section for instructions for preparing observation input files. Tables \ref{table:gwf-obstypetable} and \ref{table:gwt-obstypetable} lists observation type(s) supported by the LAK package.
GWF	LAK	OPTIONS	MOVER	KEYWORD	keyword to indicate that this instance of the LAK Package can be used with the Water Mover (MVR) Package. When the MOVER option is specified, additional memory is allocated within the package to store the available, provided, and received water.
GWF	LAK	OPTIONS	SURFDEP	DOUBLE PRECISION	real value that defines the surface depression depth for VERTICAL lake-GWF connections. If specified, SURFDEP must be greater than or equal to zero. If SURFDEP is not specified, a default value of zero is used for all vertical lake-GWF connections.
GWF	LAK	OPTIONS	MAXIMUM_ITERATIONS	INTEGER	integer value that defines the maximum number of Newton-Raphson iterations allowed for a lake. By default, MAXIMUM_ITERATIONS is equal to 100. MAXIMUM_ITERATIONS would only need to be increased from the default value if one or more lakes in a simulation has a large water budget error.
GWF	LAK	OPTIONS	MAXIMUM_STAGE_CHANGE	DOUBLE PRECISION	real value that defines the lake stage closure tolerance. By default, MAXIMUM_STAGE_CHANGE is equal to $1 \times 10^{-5}$. The MAXIMUM_STAGE_CHANGE would only need to be increased or decreased from the default value if the water budget error for one or more lakes is too small or too large, respectively.
GWF	LAK	OPTIONS	TIME_CONVERSION	DOUBLE PRECISION	real value that is used to convert user-specified Manning's roughness coefficients or gravitational acceleration used to calculate outlet flows from seconds to model time units. TIME_CONVERSION should be set to 1.0, 60.0, 3,600.0, 86,400.0, and 31,557,600.0 when using time units (TIME_UNITS) of seconds, minutes, hours, days, or years in the simulation, respectively. CONVTIME does not need to be specified if no lake outlets are specified or TIME_UNITS are seconds.
GWF	LAK	OPTIONS	LENGTH_CONVERSION	DOUBLE PRECISION	real value that is used to convert outlet user-specified Manning's roughness coefficients or gravitational acceleration used to calculate outlet flows from meters to model length units. LENGTH_CONVERSION should be set to 3.28081, 1.0, and 100.0 when using length units (LENGTH_UNITS) of feet, meters, or centimeters in the simulation, respectively. LENGTH_CONVERSION does not need to be specified if no lake outlets are specified or LENGTH_UNITS are meters.
GWF	LAK	DIMENSIONS	NLAKES	INTEGER	value specifying the number of lakes that will be simulated for all stress periods.
GWF	LAK	DIMENSIONS	NOUTLETS	INTEGER	value specifying the number of outlets that will be simulated for all stress periods. If NOUTLETS is not specified, a default value of zero is used.
GWF	LAK	DIMENSIONS	NTABLES	INTEGER	value specifying the number of lakes tables that will be used to define the lake stage, volume relation, and surface area. If NTABLES is not specified, a default value of zero is used.
GWF	LAK	PACKAGEDATA	IFNO	INTEGER	integer value that defines the feature (lake) number associated with the specified PACKAGEDATA data on the line. IFNO must be greater than zero and less than or equal to NLAKES. Lake information must be specified for every lake or the program will terminate with an error. The program will also terminate with an error if information for a lake is specified more than once.
GWF	LAK	PACKAGEDATA	STRT	DOUBLE PRECISION	real value that defines the starting stage for the lake.
GWF	LAK	PACKAGEDATA	NLAKECONN	INTEGER	integer value that defines the number of GWF cells connected to this (IFNO) lake. There can only be one vertical lake connection to each GWF cell. NLAKECONN must be greater than zero.
GWF	LAK	PACKAGEDATA	AUX	DOUBLE PRECISION (NAUX)	represents the values of the auxiliary variables for each lake. The values of auxiliary variables must be present for each lake. 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.
GWF	LAK	PACKAGEDATA	BOUNDNAME	STRING	name of the lake 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.
GWF	LAK	CONNECTIONDATA	IFNO	INTEGER	integer value that defines the feature (lake) number associated with the specified CONNECTIONDATA data on the line. IFNO must be greater than zero and less than or equal to NLAKES. Lake connection information must be specified for every lake connection to the GWF model (NLAKECONN) or the program will terminate with an error. The program will also terminate with an error if connection information for a lake connection to the GWF model is specified more than once.
GWF	LAK	CONNECTIONDATA	ICONN	INTEGER	integer value that defines the GWF connection number for this lake connection entry. ICONN must be greater than zero and less than or equal to NLAKECONN for lake IFNO.
GWF	LAK	CONNECTIONDATA	CELLID	INTEGER (NCELLDIM)	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.
GWF	LAK	CONNECTIONDATA	CLAKTYPE	STRING	character string that defines the lake-GWF connection type for the lake connection. Possible lake-GWF connection type strings include: VERTICAL--character keyword to indicate the lake-GWF connection is vertical and connection conductance calculations use the hydraulic conductivity corresponding to the $K_{33}$ tensor component defined for CELLID in the NPF package. HORIZONTAL--character keyword to indicate the lake-GWF connection is horizontal and connection conductance calculations use the hydraulic conductivity corresponding to the $K_{11}$ tensor component defined for CELLID in the NPF package. EMBEDDEDH--character keyword to indicate the lake-GWF connection is embedded in a single cell and connection conductance calculations use the hydraulic conductivity corresponding to the $K_{11}$ tensor component defined for CELLID in the NPF package. EMBEDDEDV--character keyword to indicate the lake-GWF connection is embedded in a single cell and connection conductance calculations use the hydraulic conductivity corresponding to the $K_{33}$ tensor component defined for CELLID in the NPF package. Embedded lakes can only be connected to a single cell (NLAKECONN = 1) and there must be a lake table associated with each embedded lake.
GWF	LAK	CONNECTIONDATA	BEDLEAK	STRING	real value or character string that defines the bed leakance for the lake-GWF connection. BEDLEAK must be greater than or equal to zero, equal to the DNODATA value (3.0E+30), or specified to be NONE. If DNODATA or NONE is specified for BEDLEAK, the lake-GWF connection conductance is solely a function of aquifer properties in the connected GWF cell and lakebed sediments are assumed to be absent. Warning messages will be issued if NONE is specified. Eventually the ability to specify NONE will be deprecated and cause MODFLOW 6 to terminate with an error.
GWF	LAK	CONNECTIONDATA	BELEV	DOUBLE PRECISION	real value that defines the bottom elevation for a HORIZONTAL lake-GWF connection. Any value can be specified if CLAKTYPE is VERTICAL, EMBEDDEDH, or EMBEDDEDV. If CLAKTYPE is HORIZONTAL and BELEV is not equal to TELEV, BELEV must be greater than or equal to the bottom of the GWF cell CELLID. If BELEV is equal to TELEV, BELEV is reset to the bottom of the GWF cell CELLID.
GWF	LAK	CONNECTIONDATA	TELEV	DOUBLE PRECISION	real value that defines the top elevation for a HORIZONTAL lake-GWF connection. Any value can be specified if CLAKTYPE is VERTICAL, EMBEDDEDH, or EMBEDDEDV. If CLAKTYPE is HORIZONTAL and TELEV is not equal to BELEV, TELEV must be less than or equal to the top of the GWF cell CELLID. If TELEV is equal to BELEV, TELEV is reset to the top of the GWF cell CELLID.
GWF	LAK	CONNECTIONDATA	CONNLEN	DOUBLE PRECISION	real value that defines the distance between the connected GWF CELLID node and the lake for a HORIZONTAL, EMBEDDEDH, or EMBEDDEDV lake-GWF connection. CONLENN must be greater than zero for a HORIZONTAL, EMBEDDEDH, or EMBEDDEDV lake-GWF connection. Any value can be specified if CLAKTYPE is VERTICAL.
GWF	LAK	CONNECTIONDATA	CONNWIDTH	DOUBLE PRECISION	real value that defines the connection face width for a HORIZONTAL lake-GWF connection. CONNWIDTH must be greater than zero for a HORIZONTAL lake-GWF connection. Any value can be specified if CLAKTYPE is VERTICAL, EMBEDDEDH, or EMBEDDEDV.
GWF	LAK	TABLES	IFNO	INTEGER	integer value that defines the feature (lake) number associated with the specified TABLES data on the line. IFNO must be greater than zero and less than or equal to NLAKES. The program will terminate with an error if table information for a lake is specified more than once or the number of specified tables is less than NTABLES.
GWF	LAK	TABLES	TAB6	KEYWORD	keyword to specify that record corresponds to a table file.
GWF	LAK	TABLES	FILEIN	KEYWORD	keyword to specify that an input filename is expected next.
GWF	LAK	TABLES	TAB6_FILENAME	STRING	character string that defines the path and filename for the file containing lake table data for the lake connection. The TAB6_FILENAME file includes the number of entries in the file and the relation between stage, volume, and surface area for each entry in the file. Lake table files for EMBEDDEDH and EMBEDDEDV lake-GWF connections also include lake-GWF exchange area data for each entry in the file. Instructions for creating the TAB6_FILENAME input file are provided in Lake Table Input File section.
GWF	LAK	OUTLETS	OUTLETNO	INTEGER	integer value that defines the outlet number associated with the specified OUTLETS data on the line. OUTLETNO must be greater than zero and less than or equal to NOUTLETS. Outlet information must be specified for every outlet or the program will terminate with an error. The program will also terminate with an error if information for a outlet is specified more than once.
GWF	LAK	OUTLETS	LAKEIN	INTEGER	integer value that defines the lake number that outlet is connected to. LAKEIN must be greater than zero and less than or equal to NLAKES.
GWF	LAK	OUTLETS	LAKEOUT	INTEGER	integer value that defines the lake number that outlet discharge from lake outlet OUTLETNO is routed to. LAKEOUT must be greater than or equal to zero and less than or equal to NLAKES. If LAKEOUT is zero, outlet discharge from lake outlet OUTLETNO is discharged to an external boundary.
GWF	LAK	OUTLETS	COUTTYPE	STRING	character string that defines the outlet type for the outlet OUTLETNO. Possible COUTTYPE strings include: SPECIFIED--character keyword to indicate the outlet is defined as a specified flow. MANNING--character keyword to indicate the outlet is defined using Manning's equation. WEIR--character keyword to indicate the outlet is defined using a sharp weir equation.
GWF	LAK	OUTLETS	INVERT	DOUBLE PRECISION	real value that defines the invert elevation for the lake outlet. Any value can be specified if COUTTYPE is SPECIFIED. 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.
GWF	LAK	OUTLETS	WIDTH	DOUBLE PRECISION	real value that defines the width of the lake outlet. Any value can be specified if COUTTYPE is SPECIFIED. 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.
GWF	LAK	OUTLETS	ROUGH	DOUBLE PRECISION	real value that defines the roughness coefficient for the lake outlet. Any value can be specified if COUTTYPE is not MANNING. 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.
GWF	LAK	OUTLETS	SLOPE	DOUBLE PRECISION	real value that defines the bed slope for the lake outlet. Any value can be specified if COUTTYPE is not MANNING. 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.
GWF	LAK	PERIOD	IPER	INTEGER	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.
GWF	LAK	PERIOD	NUMBER	INTEGER	integer value that defines the lake or outlet number associated with the specified PERIOD data on the line. NUMBER must be greater than zero and less than or equal to NLAKES for a lake number and less than or equal to NOUTLETS for an outlet number.
GWF	LAK	PERIOD	LAKSETTING	KEYSTRING	line of information that is parsed into a keyword and values. Keyword values that can be used to start the LAKSETTING string include both keywords for lake settings and keywords for outlet settings. Keywords for lake settings include: STATUS, STAGE, RAINFALL, EVAPORATION, RUNOFF, INFLOW, WITHDRAWAL, and AUXILIARY. Keywords for outlet settings include RATE, INVERT, WIDTH, SLOPE, and ROUGH.
GWF	LAK	PERIOD	STATUS	STRING	keyword option to define lake status. STATUS can be ACTIVE, INACTIVE, or CONSTANT. By default, STATUS is ACTIVE.
GWF	LAK	PERIOD	STAGE	STRING	real or character value that defines the stage for the lake. The specified STAGE is only applied if the lake is a constant stage lake. 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.
GWF	LAK	PERIOD	RAINFALL	STRING	real or character value that defines the rainfall rate $(LT^{-1})$ for the lake. Value must be greater than or equal to zero. 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.
GWF	LAK	PERIOD	EVAPORATION	STRING	real or character value that defines the maximum evaporation rate $(LT^{-1})$ for the lake. Value must be greater than or equal to zero. 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.
GWF	LAK	PERIOD	RUNOFF	STRING	real or character value that defines the runoff rate $(L^3 T^{-1})$ for the lake. Value must be greater than or equal to zero. 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.
GWF	LAK	PERIOD	INFLOW	STRING	real or character value that defines the volumetric inflow rate $(L^3 T^{-1})$ for the lake. Value must be greater than or equal to zero. 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. By default, inflow rates are zero for each lake.
GWF	LAK	PERIOD	WITHDRAWAL	STRING	real or character value that defines the maximum withdrawal rate $(L^3 T^{-1})$ for the lake. Value must be greater than or equal to zero. 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.
GWF	LAK	PERIOD	RATE	STRING	real or character value that defines the extraction rate for the lake outflow. A positive value indicates inflow and a negative value indicates outflow from the lake. RATE only applies to outlets associated with active lakes (STATUS is ACTIVE). A specified RATE is only applied if COUTTYPE for the OUTLETNO is SPECIFIED. 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. By default, the RATE for each SPECIFIED lake outlet is zero.
GWF	LAK	PERIOD	INVERT	STRING	real or character value that defines the invert elevation for the lake outlet. A specified INVERT value is only used for active lakes if COUTTYPE for lake outlet OUTLETNO is not SPECIFIED. 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.
GWF	LAK	PERIOD	ROUGH	STRING	real value that defines the roughness coefficient for the lake outlet. Any value can be specified if COUTTYPE is not MANNING. 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.
GWF	LAK	PERIOD	WIDTH	STRING	real or character value that defines the width of the lake outlet. A specified WIDTH value is only used for active lakes if COUTTYPE for lake outlet OUTLETNO is not SPECIFIED. 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.
GWF	LAK	PERIOD	SLOPE	STRING	real or character value that defines the bed slope for the lake outlet. A specified SLOPE value is only used for active lakes if COUTTYPE for lake outlet OUTLETNO is MANNING. 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.
GWF	LAK	PERIOD	AUXILIARY	KEYWORD	keyword for specifying auxiliary variable.
GWF	LAK	PERIOD	AUXNAME	STRING	name for the auxiliary variable to be assigned AUXVAL. AUXNAME must match one of the auxiliary variable names defined in the OPTIONS block. If AUXNAME does not match one of the auxiliary variable names defined in the OPTIONS block the data are ignored.
GWF	LAK	PERIOD	AUXVAL	DOUBLE PRECISION	value for the auxiliary variable. 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.
GWF	UZF	OPTIONS	AUXILIARY	STRING (NAUX)	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.
GWF	UZF	OPTIONS	AUXMULTNAME	STRING	name of auxiliary variable to be used as multiplier of GWF cell area used by UZF cell.
GWF	UZF	OPTIONS	BOUNDNAMES	KEYWORD	keyword to indicate that boundary names may be provided with the list of UZF cells.
GWF	UZF	OPTIONS	PRINT_INPUT	KEYWORD	keyword to indicate that the list of UZF information will be written to the listing file immediately after it is read.
GWF	UZF	OPTIONS	PRINT_FLOWS	KEYWORD	keyword to indicate that the list of UZF 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.
GWF	UZF	OPTIONS	SAVE_FLOWS	KEYWORD	keyword to indicate that UZF flow terms will be written to the file specified with ``BUDGET FILEOUT'' in Output Control.
GWF	UZF	OPTIONS	WATER_CONTENT	KEYWORD	keyword to specify that record corresponds to unsaturated zone water contents.
GWF	UZF	OPTIONS	WCFILE	STRING	name of the binary output file to write water content information.
GWF	UZF	OPTIONS	BUDGET	KEYWORD	keyword to specify that record corresponds to the budget.
GWF	UZF	OPTIONS	FILEOUT	KEYWORD	keyword to specify that an output filename is expected next.
GWF	UZF	OPTIONS	BUDGETFILE	STRING	name of the binary output file to write budget information.
GWF	UZF	OPTIONS	BUDGETCSV	KEYWORD	keyword to specify that record corresponds to the budget CSV.
GWF	UZF	OPTIONS	BUDGETCSVFILE	STRING	name of the comma-separated value (CSV) output file to write budget summary information. A budget summary record will be written to this file for each time step of the simulation.
GWF	UZF	OPTIONS	PACKAGE_CONVERGENCE	KEYWORD	keyword to specify that record corresponds to the package convergence comma spaced values file.
GWF	UZF	OPTIONS	PACKAGE_CONVERGENCE_FILENAME	STRING	name of the comma spaced values output file to write package convergence information.
GWF	UZF	OPTIONS	TS6	KEYWORD	keyword to specify that record corresponds to a time-series file.
GWF	UZF	OPTIONS	FILEIN	KEYWORD	keyword to specify that an input filename is expected next.
GWF	UZF	OPTIONS	TS6_FILENAME	STRING	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.
GWF	UZF	OPTIONS	OBS6	KEYWORD	keyword to specify that record corresponds to an observations file.
GWF	UZF	OPTIONS	OBS6_FILENAME	STRING	name of input file to define observations for the UZF package. See the ``Observation utility'' section for instructions for preparing observation input files. Tables \ref{table:gwf-obstypetable} and \ref{table:gwt-obstypetable} lists observation type(s) supported by the UZF package.
GWF	UZF	OPTIONS	MOVER	KEYWORD	keyword to indicate that this instance of the UZF Package can be used with the Water Mover (MVR) Package. When the MOVER option is specified, additional memory is allocated within the package to store the available, provided, and received water.
GWF	UZF	OPTIONS	SIMULATE_ET	KEYWORD	keyword specifying that ET in the unsaturated (UZF) and saturated zones (GWF) will be simulated. ET can be simulated in the UZF cell and not the GWF cell by omitting keywords LINEAR_GWET and SQUARE_GWET.
GWF	UZF	OPTIONS	LINEAR_GWET	KEYWORD	keyword specifying that groundwater ET will be simulated using the original ET formulation of MODFLOW-2005.
GWF	UZF	OPTIONS	SQUARE_GWET	KEYWORD	keyword specifying that groundwater ET will be simulated by assuming a constant ET rate for groundwater levels between land surface (TOP) and land surface minus the ET extinction depth (TOP-EXTDP). Groundwater ET is smoothly reduced from the PET rate to zero over a nominal interval at TOP-EXTDP.
GWF	UZF	OPTIONS	SIMULATE_GWSEEP	KEYWORD	keyword specifying that groundwater discharge (GWSEEP) to land surface will be simulated. Groundwater discharge is nonzero when groundwater head is greater than land surface. This option is no longer recommended; a better approach is to use the Drain Package with discharge scaling as a way to handle seepage to land surface. The Drain Package with discharge scaling is described in Chapter 3 of the Supplemental Technical Information.
GWF	UZF	OPTIONS	UNSAT_ETWC	KEYWORD	keyword specifying that ET in the unsaturated zone will be simulated as a function of the specified PET rate while the water content (THETA) is greater than the ET extinction water content (EXTWC).
GWF	UZF	OPTIONS	UNSAT_ETAE	KEYWORD	keyword specifying that ET in the unsaturated zone will be simulated using a capillary pressure based formulation. Capillary pressure is calculated using the Brooks-Corey retention function.
GWF	UZF	DIMENSIONS	NUZFCELLS	INTEGER	is the number of UZF cells. More than one UZF cell can be assigned to a GWF cell; however, only one GWF cell can be assigned to a single UZF cell. If more than one UZF cell is assigned to a GWF cell, then an auxiliary variable should be used to reduce the surface area of the UZF cell with the AUXMULTNAME option.
GWF	UZF	DIMENSIONS	NTRAILWAVES	INTEGER	is the number of trailing waves. A recommended value of 7 can be used for NTRAILWAVES. This value can be increased to lower mass balance error in the unsaturated zone.
GWF	UZF	DIMENSIONS	NWAVESETS	INTEGER	is the number of wave sets. A recommended value of 40 can be used for NWAVESETS. This value can be increased if more waves are required to resolve variations in water content within the unsaturated zone.
GWF	UZF	PACKAGEDATA	IFNO	INTEGER	integer value that defines the feature (UZF object) number associated with the specified PACKAGEDATA data on the line. IFNO must be greater than zero and less than or equal to NUZFCELLS. UZF information must be specified for every UZF cell or the program will terminate with an error. The program will also terminate with an error if information for a UZF cell is specified more than once.
GWF	UZF	PACKAGEDATA	CELLID	INTEGER (NCELLDIM)	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.
GWF	UZF	PACKAGEDATA	LANDFLAG	INTEGER	integer value set to one for land surface cells indicating that boundary conditions can be applied and data can be specified in the PERIOD block. A value of 0 specifies a non-land surface cell.
GWF	UZF	PACKAGEDATA	IVERTCON	INTEGER	integer value set to specify underlying UZF cell that receives water flowing to bottom of cell. If unsaturated zone flow reaches the water table before the cell bottom, then water is added to the GWF cell instead of flowing to the underlying UZF cell. A value of 0 indicates the UZF cell is not connected to an underlying UZF cell.
GWF	UZF	PACKAGEDATA	SURFDEP	DOUBLE PRECISION	is the surface depression depth of the UZF cell.
GWF	UZF	PACKAGEDATA	VKS	DOUBLE PRECISION	is the saturated vertical hydraulic conductivity of the UZF cell. This value is used with the Brooks-Corey function and the simulated water content to calculate the partially saturated hydraulic conductivity.
GWF	UZF	PACKAGEDATA	THTR	DOUBLE PRECISION	is the residual (irreducible) water content of the UZF cell. This residual water is not available to plants and will not drain into underlying aquifer cells.
GWF	UZF	PACKAGEDATA	THTS	DOUBLE PRECISION	is the saturated water content of the UZF cell. The values for saturated and residual water content should be set in a manner that is consistent with the specific yield value specified in the Storage Package. The saturated water content must be greater than the residual content.
GWF	UZF	PACKAGEDATA	THTI	DOUBLE PRECISION	is the initial water content of the UZF cell. The value must be greater than or equal to the residual water content and less than or equal to the saturated water content.
GWF	UZF	PACKAGEDATA	EPS	DOUBLE PRECISION	is the exponent used in the Brooks-Corey function. The Brooks-Corey function is used by UZF to calculated hydraulic conductivity under partially saturated conditions as a function of water content and the user-specified saturated hydraulic conductivity.
GWF	UZF	PACKAGEDATA	BOUNDNAME	STRING	name of the UZF cell 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.
GWF	UZF	PERIOD	IPER	INTEGER	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.
GWF	UZF	PERIOD	IFNO	INTEGER	integer value that defines the feature (UZF object) number associated with the specified PERIOD data on the line.
GWF	UZF	PERIOD	FINF	STRING	real or character value that defines the applied infiltration rate of the UZF cell ($LT^{-1}$). 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.
GWF	UZF	PERIOD	PET	STRING	real or character value that defines the potential evapotranspiration rate of the UZF cell and specified GWF cell. Evapotranspiration is first removed from the unsaturated zone and any remaining potential evapotranspiration is applied to the saturated zone. If IVERTCON is greater than zero then residual potential evapotranspiration not satisfied in the UZF cell is applied to the underlying UZF and GWF cells. PET is always specified, but is only used if SIMULATE_ET is specified in the OPTIONS block. 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.
GWF	UZF	PERIOD	EXTDP	STRING	real or character value that defines the evapotranspiration extinction depth of the UZF cell. If IVERTCON is greater than zero and EXTDP extends below the GWF cell bottom then remaining potential evapotranspiration is applied to the underlying UZF and GWF cells. EXTDP is always specified, but is only used if SIMULATE_ET is specified in the OPTIONS block. 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.
GWF	UZF	PERIOD	EXTWC	STRING	real or character value that defines the evapotranspiration extinction water content of the UZF cell. EXTWC is always specified, but is only used if SIMULATE_ET and UNSAT_ETWC are specified in the OPTIONS block. The evapotranspiration rate from the unsaturated zone will be set to zero when the calculated water content is at or less than this value. The value for EXTWC cannot be less than the residual water content, and if it is specified as being less than the residual water content it is set to the residual water content. 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.
GWF	UZF	PERIOD	HA	STRING	real or character value that defines the air entry potential (head) of the UZF cell. HA is always specified, but is only used if SIMULATE_ET and UNSAT_ETAE are specified in the OPTIONS block. 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.
GWF	UZF	PERIOD	HROOT	STRING	real or character value that defines the root potential (head) of the UZF cell. HROOT is always specified, but is only used if SIMULATE_ET and UNSAT_ETAE are specified in the OPTIONS block. 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.
GWF	UZF	PERIOD	ROOTACT	STRING	real or character value that defines the root activity function of the UZF cell. ROOTACT is the length of roots in a given volume of soil divided by that volume. Values range from 0 to about 3 $cm^{-2}$, depending on the plant community and its stage of development. ROOTACT is always specified, but is only used if SIMULATE_ET and UNSAT_ETAE are specified in the OPTIONS block. 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.
GWF	UZF	PERIOD	AUX	DOUBLE PRECISION (NAUX)	represents the values of the auxiliary variables for each UZF. The values of auxiliary variables must be present for each UZF. 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.
GWF	MVR	OPTIONS	PRINT_INPUT	KEYWORD	keyword to indicate that the list of MVR information will be written to the listing file immediately after it is read.
GWF	MVR	OPTIONS	PRINT_FLOWS	KEYWORD	keyword to indicate that the list of MVR 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.
GWF	MVR	OPTIONS	MODELNAMES	KEYWORD	keyword to indicate that all package names will be preceded by the model name for the package. Model names are required when the Mover Package is used with a GWF-GWF Exchange. The MODELNAME keyword should not be used for a Mover Package that is for a single GWF Model.
GWF	MVR	OPTIONS	BUDGET	KEYWORD	keyword to specify that record corresponds to the budget.
GWF	MVR	OPTIONS	FILEOUT	KEYWORD	keyword to specify that an output filename is expected next.
GWF	MVR	OPTIONS	BUDGETFILE	STRING	name of the output file to write budget information.
GWF	MVR	OPTIONS	BUDGETCSV	KEYWORD	keyword to specify that record corresponds to the budget CSV.
GWF	MVR	OPTIONS	BUDGETCSVFILE	STRING	name of the comma-separated value (CSV) output file to write budget summary information. A budget summary record will be written to this file for each time step of the simulation.
GWF	MVR	DIMENSIONS	MAXMVR	INTEGER	integer value specifying the maximum number of water mover entries that will specified for any stress period.
GWF	MVR	DIMENSIONS	MAXPACKAGES	INTEGER	integer value specifying the number of unique packages that are included in this water mover input file.
GWF	MVR	PACKAGES	MNAME	STRING	name of model containing the package. Model names are assigned by the user in the simulation name file.
GWF	MVR	PACKAGES	PNAME	STRING	is the name of a package that may be included in a subsequent stress period block. The package name is assigned in the name file for the GWF Model. Package names are optionally provided in the name file. If they are not provided by the user, then packages are assigned a default value, which is the package acronym followed by a hyphen and the package number. For example, the first Drain Package is named DRN-1. The second Drain Package is named DRN-2, and so forth.
GWF	MVR	PERIOD	IPER	INTEGER	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.
GWF	MVR	PERIOD	MNAME1	STRING	name of model containing the package, PNAME1.
GWF	MVR	PERIOD	PNAME1	STRING	is the package name for the provider. The package PNAME1 must be designated to provide water through the MVR Package by specifying the keyword ``MOVER'' in its OPTIONS block.
GWF	MVR	PERIOD	ID1	INTEGER	is the identifier for the provider. For the standard boundary packages, the provider identifier is the number of the boundary as it is listed in the package input file. (Note that the order of these boundaries may change by stress period, which must be accounted for in the Mover Package.) So the first well has an identifier of one. The second is two, and so forth. For the advanced packages, the identifier is the reach number (SFR Package), well number (MAW Package), or UZF cell number. For the Lake Package, ID1 is the lake outlet number. Thus, outflows from a single lake can be routed to different streams, for example.
GWF	MVR	PERIOD	MNAME2	STRING	name of model containing the package, PNAME2.
GWF	MVR	PERIOD	PNAME2	STRING	is the package name for the receiver. The package PNAME2 must be designated to receive water from the MVR Package by specifying the keyword ``MOVER'' in its OPTIONS block.
GWF	MVR	PERIOD	ID2	INTEGER	is the identifier for the receiver. The receiver identifier is the reach number (SFR Package), Lake number (LAK Package), well number (MAW Package), or UZF cell number.
GWF	MVR	PERIOD	MVRTYPE	STRING	is the character string signifying the method for determining how much water will be moved. Supported values are FACTOR'' EXCESS'' THRESHOLD'' and UPTO''. These four options determine how the receiver flow rate, $Q_R$, is calculated. These options mirror the options defined for the cprior variable in the SFR package, with the term FACTOR'' being functionally equivalent to the FRACTION'' option for cprior.
GWF	MVR	PERIOD	VALUE	DOUBLE PRECISION	is the value to be used in the equation for calculating the amount of water to move. For the ``FACTOR'' option, VALUE is the $\alpha$ factor. For the remaining options, VALUE is the specified flow rate, $Q_S$.
GWF	GNC	OPTIONS	PRINT_INPUT	KEYWORD	keyword to indicate that the list of GNC information will be written to the listing file immediately after it is read.
GWF	GNC	OPTIONS	PRINT_FLOWS	KEYWORD	keyword to indicate that the list of GNC 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.
GWF	GNC	OPTIONS	EXPLICIT	KEYWORD	keyword to indicate that the ghost node correction is applied in an explicit manner on the right-hand side of the matrix. The explicit approach will likely require additional outer iterations. If the keyword is not specified, then the correction will be applied in an implicit manner on the left-hand side. The implicit approach will likely converge better, but may require additional memory. If the EXPLICIT keyword is not specified, then the BICGSTAB linear acceleration option should be specified within the LINEAR block of the Sparse Matrix Solver.
GWF	GNC	DIMENSIONS	NUMGNC	INTEGER	is the number of GNC entries.
GWF	GNC	DIMENSIONS	NUMALPHAJ	INTEGER	is the number of contributing factors.
GWF	GNC	GNCDATA	CELLIDN	INTEGER	is the cellid of the cell, $n$, in which the ghost node is located. For a structured grid that uses the DIS input file, CELLIDN is the layer, row, and column numbers of the cell. For a grid that uses the DISV input file, CELLIDN is the layer number and CELL2D number for the two cells. If the model uses the unstructured discretization (DISU) input file, then CELLIDN is the node number for the cell.
GWF	GNC	GNCDATA	CELLIDM	INTEGER	is the cellid of the connecting cell, $m$, to which flow occurs from the ghost node. For a structured grid that uses the DIS input file, CELLIDM is the layer, row, and column numbers of the cell. For a grid that uses the DISV input file, CELLIDM is the layer number and CELL2D number for the two cells. If the model uses the unstructured discretization (DISU) input file, then CELLIDM is the node number for the cell.
GWF	GNC	GNCDATA	CELLIDSJ	INTEGER (NUMALPHAJ)	is the array of CELLIDS for the contributing j cells, which contribute to the interpolated head value at the ghost node. This item contains one CELLID for each of the contributing cells of the ghost node. Note that if the number of actual contributing cells needed by the user is less than NUMALPHAJ for any ghost node, then a dummy CELLID of zero(s) should be inserted with an associated contributing factor of zero. For a structured grid that uses the DIS input file, CELLID is the layer, row, and column numbers of the cell. For a grid that uses the DISV input file, CELLID is the layer number and cell2d number for the two cells. If the model uses the unstructured discretization (DISU) input file, then CELLID is the node number for the cell.
GWF	GNC	GNCDATA	ALPHASJ	DOUBLE PRECISION (NUMALPHAJ)	is the contributing factors for each contributing node in CELLIDSJ. Note that if the number of actual contributing cells is less than NUMALPHAJ for any ghost node, then dummy CELLIDS should be inserted with an associated contributing factor of zero. The sum of ALPHASJ should be less than one. This is because one minus the sum of ALPHASJ is equal to the alpha term (alpha n in equation 4-61 of the GWF Model report) that is multiplied by the head in cell n.
GWF	OC	OPTIONS	BUDGET	KEYWORD	keyword to specify that record corresponds to the budget.
GWF	OC	OPTIONS	FILEOUT	KEYWORD	keyword to specify that an output filename is expected next.
GWF	OC	OPTIONS	BUDGETFILE	STRING	name of the output file to write budget information.
GWF	OC	OPTIONS	BUDGETCSV	KEYWORD	keyword to specify that record corresponds to the budget CSV.
GWF	OC	OPTIONS	BUDGETCSVFILE	STRING	name of the comma-separated value (CSV) output file to write budget summary information. A budget summary record will be written to this file for each time step of the simulation.
GWF	OC	OPTIONS	HEAD	KEYWORD	keyword to specify that record corresponds to head.
GWF	OC	OPTIONS	HEADFILE	STRING	name of the output file to write head information.
GWF	OC	OPTIONS	PRINT_FORMAT	KEYWORD	keyword to specify format for printing to the listing file.
GWF	OC	OPTIONS	COLUMNS	INTEGER	number of columns for writing data.
GWF	OC	OPTIONS	WIDTH	INTEGER	width for writing each number.
GWF	OC	OPTIONS	DIGITS	INTEGER	number of digits to use for writing a number.
GWF	OC	OPTIONS	FORMAT	STRING	write format can be EXPONENTIAL, FIXED, GENERAL, or SCIENTIFIC.
GWF	OC	PERIOD	IPER	INTEGER	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.
GWF	OC	PERIOD	SAVE	KEYWORD	keyword to indicate that information will be saved this stress period.
GWF	OC	PERIOD	PRINT	KEYWORD	keyword to indicate that information will be printed this stress period.
GWF	OC	PERIOD	RTYPE	STRING	type of information to save or print. Can be BUDGET or HEAD.
GWF	OC	PERIOD	OCSETTING	KEYSTRING	specifies the steps for which the data will be saved.
GWF	OC	PERIOD	ALL	KEYWORD	keyword to indicate save for all time steps in period.
GWF	OC	PERIOD	FIRST	KEYWORD	keyword to indicate save for first step in period. This keyword may be used in conjunction with other keywords to print or save results for multiple time steps.
GWF	OC	PERIOD	LAST	KEYWORD	keyword to indicate save for last step in period. This keyword may be used in conjunction with other keywords to print or save results for multiple time steps.
GWF	OC	PERIOD	FREQUENCY	INTEGER	save at the specified time step frequency. This keyword may be used in conjunction with other keywords to print or save results for multiple time steps.
GWF	OC	PERIOD	STEPS	INTEGER (<NSTP)	save for each step specified in STEPS. This keyword may be used in conjunction with other keywords to print or save results for multiple time steps.
GWF	VSC	OPTIONS	VISCREF	DOUBLE PRECISION	fluid reference viscosity used in the equation of state. This value is set to 1.0 if not specified as an option.
GWF	VSC	OPTIONS	TEMPERATURE_SPECIES_NAME	STRING	string used to identify the auxspeciesname in PACKAGEDATA that corresponds to the temperature species. There can be only one occurrence of this temperature species name in the PACKAGEDATA block or the program will terminate with an error. This value has no effect if viscosity does not depend on temperature.
GWF	VSC	OPTIONS	THERMAL_FORMULATION	STRING	may be used for specifying which viscosity formulation to use for the temperature species. Can be either LINEAR or NONLINEAR. The LINEAR viscosity formulation is the default.
GWF	VSC	OPTIONS	THERMAL_A2	DOUBLE PRECISION	is an empirical parameter specified by the user for calculating viscosity using a nonlinear formulation. If A2 is not specified, a default value of 10.0 is assigned (Voss, 1984).
GWF	VSC	OPTIONS	THERMAL_A3	DOUBLE PRECISION	is an empirical parameter specified by the user for calculating viscosity using a nonlinear formulation. If A3 is not specified, a default value of 248.37 is assigned (Voss, 1984).
GWF	VSC	OPTIONS	THERMAL_A4	DOUBLE PRECISION	is an empirical parameter specified by the user for calculating viscosity using a nonlinear formulation. If A4 is not specified, a default value of 133.15 is assigned (Voss, 1984).
GWF	VSC	OPTIONS	VISCOSITY	KEYWORD	keyword to specify that record corresponds to viscosity.
GWF	VSC	OPTIONS	FILEOUT	KEYWORD	keyword to specify that an output filename is expected next.
GWF	VSC	OPTIONS	VISCOSITYFILE	STRING	name of the binary output file to write viscosity information. The viscosity file has the same format as the head file. Viscosity values will be written to the viscosity file whenever heads are written to the binary head file. The settings for controlling head output are contained in the Output Control option.
GWF	VSC	DIMENSIONS	NVISCSPECIES	INTEGER	number of species used in the viscosity equation of state. If either concentrations or temperature (or both) are used to update viscosity then then nrhospecies needs to be at least one.
GWF	VSC	PACKAGEDATA	IVISCSPEC	INTEGER	integer value that defines the species number associated with the specified PACKAGEDATA data entered on each line. IVISCSPECIES must be greater than zero and less than or equal to NVISCSPECIES. Information must be specified for each of the NVISCSPECIES species or the program will terminate with an error. The program will also terminate with an error if information for a species is specified more than once.
GWF	VSC	PACKAGEDATA	DVISCDC	DOUBLE PRECISION	real value that defines the slope of the line defining the linear relationship between viscosity and temperature or between viscosity and concentration, depending on the type of species entered on each line. If the value of AUXSPECIESNAME entered on a line corresponds to TEMPERATURE_SPECIES_NAME (in the OPTIONS block), this value will be used when VISCOSITY_FUNC is equal to LINEAR (the default) in the OPTIONS block. When VISCOSITY_FUNC is set to NONLINEAR, a value for DVISCDC must be specified though it is not used.
GWF	VSC	PACKAGEDATA	CVISCREF	DOUBLE PRECISION	real value that defines the reference temperature or reference concentration value used for this species in the viscosity equation of state. If AUXSPECIESNAME entered on a line corresponds to TEMPERATURE_SPECIES_NAME (in the OPTIONS block), then CVISCREF refers to a reference temperature, otherwise it refers to a reference concentration.
GWF	VSC	PACKAGEDATA	MODELNAME	STRING	name of a GWT model used to simulate a species that will be used in the viscosity equation of state. This name will have no effect if the simulation does not include a GWT model that corresponds to this GWF model.
GWF	VSC	PACKAGEDATA	AUXSPECIESNAME	STRING	name of an auxiliary variable in a GWF stress package that will be used for this species to calculate the viscosity values. If a viscosity value is needed by the Viscosity Package then it will use the temperature or concentration values associated with this AUXSPECIESNAME in the viscosity equation of state. For advanced stress packages (LAK, SFR, MAW, and UZF) that have an associated advanced transport package (LKT, SFT, MWT, and UZT), the FLOW_PACKAGE_AUXILIARY_NAME option in the advanced transport package can be used to transfer simulated temperature or concentration(s) into the flow package auxiliary variable. In this manner, the Viscosity Package can calculate viscosity values for lakes, streams, multi-aquifer wells, and unsaturated zone flow cells using simulated concentrations.
GWF	API	OPTIONS	BOUNDNAMES	KEYWORD	keyword to indicate that boundary names may be provided with the list of api boundary cells.
GWF	API	OPTIONS	PRINT_INPUT	KEYWORD	keyword to indicate that the list of api boundary information will be written to the listing file immediately after it is read.
GWF	API	OPTIONS	PRINT_FLOWS	KEYWORD	keyword to indicate that the list of api boundary 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.
GWF	API	OPTIONS	SAVE_FLOWS	KEYWORD	keyword to indicate that api boundary flow terms will be written to the file specified with ``BUDGET FILEOUT'' in Output Control.
GWF	API	OPTIONS	OBS6	KEYWORD	keyword to specify that record corresponds to an observations file.
GWF	API	OPTIONS	FILEIN	KEYWORD	keyword to specify that an input filename is expected next.
GWF	API	OPTIONS	OBS6_FILENAME	STRING	name of input file to define observations for the api boundary package. See the ``Observation utility'' section for instructions for preparing observation input files. Tables \ref{table:gwf-obstypetable} and \ref{table:gwt-obstypetable} lists observation type(s) supported by the api boundary package.
GWF	API	OPTIONS	MOVER	KEYWORD	keyword to indicate that this instance of the api boundary Package can be used with the Water Mover (MVR) Package. When the MOVER option is specified, additional memory is allocated within the package to store the available, provided, and received water.
GWF	API	DIMENSIONS	MAXBOUND	INTEGER	integer value specifying the maximum number of api boundary cells that will be specified for use during any stress period.
GWT	ADV	OPTIONS	SCHEME	STRING	scheme used to solve the advection term. Can be upstream, central, or TVD. If not specified, upstream weighting is the default weighting scheme.
GWT	DSP	OPTIONS	XT3D_OFF	KEYWORD	deactivate the xt3d method and use the faster and less accurate approximation. This option may provide a fast and accurate solution under some circumstances, such as when flow aligns with the model grid, there is no mechanical dispersion, or when the longitudinal and transverse dispersivities are equal. This option may also be used to assess the computational demand of the XT3D approach by noting the run time differences with and without this option on.
GWT	DSP	OPTIONS	XT3D_RHS	KEYWORD	add xt3d terms to right-hand side, when possible. This option uses less memory, but may require more iterations.
GWT	DSP	GRIDDATA	DIFFC	DOUBLE PRECISION (NODES)	effective molecular diffusion coefficient.
GWT	DSP	GRIDDATA	ALH	DOUBLE PRECISION (NODES)	longitudinal dispersivity in horizontal direction. If flow is strictly horizontal, then this is the longitudinal dispersivity that will be used. If flow is not strictly horizontal or strictly vertical, then the longitudinal dispersivity is a function of both ALH and ALV. If mechanical dispersion is represented (by specifying any dispersivity values) then this array is required.
GWT	DSP	GRIDDATA	ALV	DOUBLE PRECISION (NODES)	longitudinal dispersivity in vertical direction. If flow is strictly vertical, then this is the longitudinal dispsersivity value that will be used. If flow is not strictly horizontal or strictly vertical, then the longitudinal dispersivity is a function of both ALH and ALV. If this value is not specified and mechanical dispersion is represented, then this array is set equal to ALH.
GWT	DSP	GRIDDATA	ATH1	DOUBLE PRECISION (NODES)	transverse dispersivity in horizontal direction. This is the transverse dispersivity value for the second ellipsoid axis. If flow is strictly horizontal and directed in the x direction (along a row for a regular grid), then this value controls spreading in the y direction. If mechanical dispersion is represented (by specifying any dispersivity values) then this array is required.
GWT	DSP	GRIDDATA	ATH2	DOUBLE PRECISION (NODES)	transverse dispersivity in horizontal direction. This is the transverse dispersivity value for the third ellipsoid axis. If flow is strictly horizontal and directed in the x direction (along a row for a regular grid), then this value controls spreading in the z direction. If this value is not specified and mechanical dispersion is represented, then this array is set equal to ATH1.
GWT	DSP	GRIDDATA	ATV	DOUBLE PRECISION (NODES)	transverse dispersivity when flow is in vertical direction. If flow is strictly vertical and directed in the z direction, then this value controls spreading in the x and y directions. If this value is not specified and mechanical dispersion is represented, then this array is set equal to ATH2.
GWT	CNC	OPTIONS	AUXILIARY	STRING (NAUX)	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.
GWT	CNC	OPTIONS	AUXMULTNAME	STRING	name of auxiliary variable to be used as multiplier of concentration value.
GWT	CNC	OPTIONS	BOUNDNAMES	KEYWORD	keyword to indicate that boundary names may be provided with the list of constant concentration cells.
GWT	CNC	OPTIONS	PRINT_INPUT	KEYWORD	keyword to indicate that the list of constant concentration information will be written to the listing file immediately after it is read.
GWT	CNC	OPTIONS	PRINT_FLOWS	KEYWORD	keyword to indicate that the list of constant concentration 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.
GWT	CNC	OPTIONS	SAVE_FLOWS	KEYWORD	keyword to indicate that constant concentration flow terms will be written to the file specified with ``BUDGET FILEOUT'' in Output Control.
GWT	CNC	OPTIONS	TS6	KEYWORD	keyword to specify that record corresponds to a time-series file.
GWT	CNC	OPTIONS	FILEIN	KEYWORD	keyword to specify that an input filename is expected next.
GWT	CNC	OPTIONS	TS6_FILENAME	STRING	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.
GWT	CNC	OPTIONS	OBS6	KEYWORD	keyword to specify that record corresponds to an observations file.
GWT	CNC	OPTIONS	OBS6_FILENAME	STRING	name of input file to define observations for the Constant Concentration package. See the ``Observation utility'' section for instructions for preparing observation input files. Tables \ref{table:gwf-obstypetable} and \ref{table:gwt-obstypetable} lists observation type(s) supported by the Constant Concentration package.
GWT	CNC	DIMENSIONS	MAXBOUND	INTEGER	integer value specifying the maximum number of constant concentrations cells that will be specified for use during any stress period.
GWT	CNC	PERIOD	IPER	INTEGER	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.
GWT	CNC	PERIOD	CELLID	INTEGER (NCELLDIM)	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.
GWT	CNC	PERIOD	CONC	DOUBLE PRECISION	is the constant concentration value. 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.
GWT	CNC	PERIOD	AUX	DOUBLE PRECISION (NAUX)	represents the values of the auxiliary variables for each constant concentration. The values of auxiliary variables must be present for each constant concentration. 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.
GWT	CNC	PERIOD	BOUNDNAME	STRING	name of the constant concentration 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.
GWT	DIS	OPTIONS	LENGTH_UNITS	STRING	is the length units used for this model. Values can be FEET'', METERS'', or CENTIMETERS''. If not specified, the default is UNKNOWN''.
GWT	DIS	OPTIONS	NOGRB	KEYWORD	keyword to deactivate writing of the binary grid file.
GWT	DIS	OPTIONS	XORIGIN	DOUBLE PRECISION	x-position of the lower-left corner of the model grid. A default value of zero is assigned if not specified. The value for XORIGIN does not affect the model simulation, but it is written to the binary grid file so that postprocessors can locate the grid in space.
GWT	DIS	OPTIONS	YORIGIN	DOUBLE PRECISION	y-position of the lower-left corner of the model grid. If not specified, then a default value equal to zero is used. The value for YORIGIN does not affect the model simulation, but it is written to the binary grid file so that postprocessors can locate the grid in space.
GWT	DIS	OPTIONS	ANGROT	DOUBLE PRECISION	counter-clockwise rotation angle (in degrees) of the lower-left corner of the model grid. If not specified, then a default value of 0.0 is assigned. The value for ANGROT does not affect the model simulation, but it is written to the binary grid file so that postprocessors can locate the grid in space.
GWT	DIS	DIMENSIONS	NLAY	INTEGER	is the number of layers in the model grid.
GWT	DIS	DIMENSIONS	NROW	INTEGER	is the number of rows in the model grid.
GWT	DIS	DIMENSIONS	NCOL	INTEGER	is the number of columns in the model grid.
GWT	DIS	GRIDDATA	DELR	DOUBLE PRECISION (NCOL)	is the column spacing in the row direction.
GWT	DIS	GRIDDATA	DELC	DOUBLE PRECISION (NROW)	is the row spacing in the column direction.
GWT	DIS	GRIDDATA	TOP	DOUBLE PRECISION (NCOL, NROW)	is the top elevation for each cell in the top model layer.
GWT	DIS	GRIDDATA	BOTM	DOUBLE PRECISION (NCOL, NROW, NLAY)	is the bottom elevation for each cell.
GWT	DIS	GRIDDATA	IDOMAIN	INTEGER (NCOL, NROW, NLAY)	is an optional array that characterizes the existence status of a cell. If the IDOMAIN array is not specified, then all model cells exist within the solution. If the IDOMAIN value for a cell is 0, the cell does not exist in the simulation. Input and output values will be read and written for the cell, but internal to the program, the cell is excluded from the solution. If the IDOMAIN value for a cell is 1, the cell exists in the simulation. If the IDOMAIN value for a cell is -1, the cell does not exist in the simulation. Furthermore, the first existing cell above will be connected to the first existing cell below. This type of cell is referred to as a ``vertical pass through'' cell.
GWT	DISV	OPTIONS	LENGTH_UNITS	STRING	is the length units used for this model. Values can be FEET'', METERS'', or CENTIMETERS''. If not specified, the default is UNKNOWN''.
GWT	DISV	OPTIONS	NOGRB	KEYWORD	keyword to deactivate writing of the binary grid file.
GWT	DISV	OPTIONS	XORIGIN	DOUBLE PRECISION	x-position of the origin used for model grid vertices. This value should be provided in a real-world coordinate system. A default value of zero is assigned if not specified. The value for XORIGIN does not affect the model simulation, but it is written to the binary grid file so that postprocessors can locate the grid in space.
GWT	DISV	OPTIONS	YORIGIN	DOUBLE PRECISION	y-position of the origin used for model grid vertices. This value should be provided in a real-world coordinate system. If not specified, then a default value equal to zero is used. The value for YORIGIN does not affect the model simulation, but it is written to the binary grid file so that postprocessors can locate the grid in space.
GWT	DISV	OPTIONS	ANGROT	DOUBLE PRECISION	counter-clockwise rotation angle (in degrees) of the model grid coordinate system relative to a real-world coordinate system. If not specified, then a default value of 0.0 is assigned. The value for ANGROT does not affect the model simulation, but it is written to the binary grid file so that postprocessors can locate the grid in space.
GWT	DISV	DIMENSIONS	NLAY	INTEGER	is the number of layers in the model grid.
GWT	DISV	DIMENSIONS	NCPL	INTEGER	is the number of cells per layer. This is a constant value for the grid and it applies to all layers.
GWT	DISV	DIMENSIONS	NVERT	INTEGER	is the total number of (x, y) vertex pairs used to characterize the horizontal configuration of the model grid.
GWT	DISV	GRIDDATA	TOP	DOUBLE PRECISION (NCPL)	is the top elevation for each cell in the top model layer.
GWT	DISV	GRIDDATA	BOTM	DOUBLE PRECISION (NCPL, NLAY)	is the bottom elevation for each cell.
GWT	DISV	GRIDDATA	IDOMAIN	INTEGER (NCPL, NLAY)	is an optional array that characterizes the existence status of a cell. If the IDOMAIN array is not specified, then all model cells exist within the solution. If the IDOMAIN value for a cell is 0, the cell does not exist in the simulation. Input and output values will be read and written for the cell, but internal to the program, the cell is excluded from the solution. If the IDOMAIN value for a cell is 1, the cell exists in the simulation. If the IDOMAIN value for a cell is -1, the cell does not exist in the simulation. Furthermore, the first existing cell above will be connected to the first existing cell below. This type of cell is referred to as a ``vertical pass through'' cell.
GWT	DISV	VERTICES	IV	INTEGER	is the vertex number. Records in the VERTICES block must be listed in consecutive order from 1 to NVERT.
GWT	DISV	VERTICES	XV	DOUBLE PRECISION	is the x-coordinate for the vertex.
GWT	DISV	VERTICES	YV	DOUBLE PRECISION	is the y-coordinate for the vertex.
GWT	DISV	CELL2D	ICELL2D	INTEGER	is the CELL2D number. Records in the CELL2D block must be listed in consecutive order from the first to the last.
GWT	DISV	CELL2D	XC	DOUBLE PRECISION	is the x-coordinate for the cell center.
GWT	DISV	CELL2D	YC	DOUBLE PRECISION	is the y-coordinate for the cell center.
GWT	DISV	CELL2D	NCVERT	INTEGER	is the number of vertices required to define the cell. There may be a different number of vertices for each cell.
GWT	DISV	CELL2D	ICVERT	INTEGER (NCVERT)	is an array of integer values containing vertex numbers (in the VERTICES block) used to define the cell. Vertices must be listed in clockwise order. Cells that are connected must share vertices.
GWT	DISU	OPTIONS	LENGTH_UNITS	STRING	is the length units used for this model. Values can be FEET'', METERS'', or CENTIMETERS''. If not specified, the default is UNKNOWN''.
GWT	DISU	OPTIONS	NOGRB	KEYWORD	keyword to deactivate writing of the binary grid file.
GWT	DISU	OPTIONS	XORIGIN	DOUBLE PRECISION	x-position of the origin used for model grid vertices. This value should be provided in a real-world coordinate system. A default value of zero is assigned if not specified. The value for XORIGIN does not affect the model simulation, but it is written to the binary grid file so that postprocessors can locate the grid in space.
GWT	DISU	OPTIONS	YORIGIN	DOUBLE PRECISION	y-position of the origin used for model grid vertices. This value should be provided in a real-world coordinate system. If not specified, then a default value equal to zero is used. The value for YORIGIN does not affect the model simulation, but it is written to the binary grid file so that postprocessors can locate the grid in space.
GWT	DISU	OPTIONS	ANGROT	DOUBLE PRECISION	counter-clockwise rotation angle (in degrees) of the model grid coordinate system relative to a real-world coordinate system. If not specified, then a default value of 0.0 is assigned. The value for ANGROT does not affect the model simulation, but it is written to the binary grid file so that postprocessors can locate the grid in space.
GWT	DISU	OPTIONS	VERTICAL_OFFSET_TOLERANCE	DOUBLE PRECISION	checks are performed to ensure that the top of a cell is not higher than the bottom of an overlying cell. This option can be used to specify the tolerance that is used for checking. If top of a cell is above the bottom of an overlying cell by a value less than this tolerance, then the program will not terminate with an error. The default value is zero. This option should generally not be used.
GWT	DISU	DIMENSIONS	NODES	INTEGER	is the number of cells in the model grid.
GWT	DISU	DIMENSIONS	NJA	INTEGER	is the sum of the number of connections and NODES. When calculating the total number of connections, the connection between cell n and cell m is considered to be different from the connection between cell m and cell n. Thus, NJA is equal to the total number of connections, including n to m and m to n, and the total number of cells.
GWT	DISU	DIMENSIONS	NVERT	INTEGER	is the total number of (x, y) vertex pairs used to define the plan-view shape of each cell in the model grid. If NVERT is not specified or is specified as zero, then the VERTICES and CELL2D blocks below are not read. NVERT and the accompanying VERTICES and CELL2D blocks should be specified for most simulations. If the XT3D or SAVE_SPECIFIC_DISCHARGE options are specified in the NPF Package, then this information is required.
GWT	DISU	GRIDDATA	TOP	DOUBLE PRECISION (NODES)	is the top elevation for each cell in the model grid.
GWT	DISU	GRIDDATA	BOT	DOUBLE PRECISION (NODES)	is the bottom elevation for each cell.
GWT	DISU	GRIDDATA	AREA	DOUBLE PRECISION (NODES)	is the cell surface area (in plan view).
GWT	DISU	GRIDDATA	IDOMAIN	INTEGER (NODES)	is an optional array that characterizes the existence status of a cell. If the IDOMAIN array is not specified, then all model cells exist within the solution. If the IDOMAIN value for a cell is 0, the cell does not exist in the simulation. Input and output values will be read and written for the cell, but internal to the program, the cell is excluded from the solution. If the IDOMAIN value for a cell is 1 or greater, the cell exists in the simulation. IDOMAIN values of -1 cannot be specified for the DISU Package.
GWT	DISU	CONNECTIONDATA	IAC	INTEGER (NODES)	is the number of connections (plus 1) for each cell. The sum of all the entries in IAC must be equal to NJA.
GWT	DISU	CONNECTIONDATA	JA	INTEGER (NJA)	is a list of cell number (n) followed by its connecting cell numbers (m) for each of the m cells connected to cell n. The number of values to provide for cell n is IAC(n). This list is sequentially provided for the first to the last cell. The first value in the list must be cell n itself, and the remaining cells must be listed in an increasing order (sorted from lowest number to highest). Note that the cell and its connections are only supplied for the GWT cells and their connections to the other GWT cells. Also note that the JA list input may be divided such that every node and its connectivity list can be on a separate line for ease in readability of the file. To further ease readability of the file, the node number of the cell whose connectivity is subsequently listed, may be expressed as a negative number, the sign of which is subsequently converted to positive by the code.
GWT	DISU	CONNECTIONDATA	IHC	INTEGER (NJA)	is an index array indicating the direction between node n and all of its m connections. If IHC = 0 then cell n and cell m are connected in the vertical direction. Cell n overlies cell m if the cell number for n is less than m; cell m overlies cell n if the cell number for m is less than n. If IHC = 1 then cell n and cell m are connected in the horizontal direction. If IHC = 2 then cell n and cell m are connected in the horizontal direction, and the connection is vertically staggered. A vertically staggered connection is one in which a cell is horizontally connected to more than one cell in a horizontal connection.
GWT	DISU	CONNECTIONDATA	CL12	DOUBLE PRECISION (NJA)	is the array containing connection lengths between the center of cell n and the shared face with each adjacent m cell.
GWT	DISU	CONNECTIONDATA	HWVA	DOUBLE PRECISION (NJA)	is a symmetric array of size NJA. For horizontal connections, entries in HWVA are the horizontal width perpendicular to flow. For vertical connections, entries in HWVA are the vertical area for flow. Thus, values in the HWVA array contain dimensions of both length and area. Entries in the HWVA array have a one-to-one correspondence with the connections specified in the JA array. Likewise, there is a one-to-one correspondence between entries in the HWVA array and entries in the IHC array, which specifies the connection type (horizontal or vertical). Entries in the HWVA array must be symmetric; the program will terminate with an error if the value for HWVA for an n to m connection does not equal the value for HWVA for the corresponding n to m connection.
GWT	DISU	CONNECTIONDATA	ANGLDEGX	DOUBLE PRECISION (NJA)	is the angle (in degrees) between the horizontal x-axis and the outward normal to the face between a cell and its connecting cells. The angle varies between zero and 360.0 degrees, where zero degrees points in the positive x-axis direction, and 90 degrees points in the positive y-axis direction. ANGLDEGX is only needed if horizontal anisotropy is specified in the NPF Package, if the XT3D option is used in the NPF Package, or if the SAVE_SPECIFIC_DISCHARGE option is specifed in the NPF Package. ANGLDEGX does not need to be specified if these conditions are not met. ANGLDEGX is of size NJA; values specified for vertical connections and for the diagonal position are not used. Note that ANGLDEGX is read in degrees, which is different from MODFLOW-USG, which reads a similar variable (ANGLEX) in radians.
GWT	DISU	VERTICES	IV	INTEGER	is the vertex number. Records in the VERTICES block must be listed in consecutive order from 1 to NVERT.
GWT	DISU	VERTICES	XV	DOUBLE PRECISION	is the x-coordinate for the vertex.
GWT	DISU	VERTICES	YV	DOUBLE PRECISION	is the y-coordinate for the vertex.
GWT	DISU	CELL2D	ICELL2D	INTEGER	is the cell2d number. Records in the CELL2D block must be listed in consecutive order from 1 to NODES.
GWT	DISU	CELL2D	XC	DOUBLE PRECISION	is the x-coordinate for the cell center.
GWT	DISU	CELL2D	YC	DOUBLE PRECISION	is the y-coordinate for the cell center.
GWT	DISU	CELL2D	NCVERT	INTEGER	is the number of vertices required to define the cell. There may be a different number of vertices for each cell.
GWT	DISU	CELL2D	ICVERT	INTEGER (NCVERT)	is an array of integer values containing vertex numbers (in the VERTICES block) used to define the cell. Vertices must be listed in clockwise order.
GWT	IC	GRIDDATA	STRT	DOUBLE PRECISION (NODES)	is the initial (starting) concentration---that is, concentration at the beginning of the GWT Model simulation. STRT must be specified for all GWT Model simulations. One value is read for every model cell.
GWT	NAM	OPTIONS	LIST	STRING	is name of the listing file to create for this GWT model. If not specified, then the name of the list file will be the basename of the GWT model name file and the '.lst' extension. For example, if the GWT name file is called my.model.nam'' then the list file will be called my.model.lst''.
GWT	NAM	OPTIONS	PRINT_INPUT	KEYWORD	keyword to indicate that the list of all model stress package information will be written to the listing file immediately after it is read.
GWT	NAM	OPTIONS	PRINT_FLOWS	KEYWORD	keyword to indicate that the list of all model package 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.
GWT	NAM	OPTIONS	SAVE_FLOWS	KEYWORD	keyword to indicate that all model package flow terms will be written to the file specified with ``BUDGET FILEOUT'' in Output Control.
GWT	NAM	PACKAGES	FTYPE	STRING	is the file type, which must be one of the following character values shown in table~\ref{table:ftype}. Ftype may be entered in any combination of uppercase and lowercase.
GWT	NAM	PACKAGES	FNAME	STRING	is the name of the file containing the package input. The path to the file should be included if the file is not located in the folder where the program was run.
GWT	NAM	PACKAGES	PNAME	STRING	is the user-defined name for the package. PNAME is restricted to 16 characters. No spaces are allowed in PNAME. PNAME character values are read and stored by the program for stress packages only. These names may be useful for labeling purposes when multiple stress packages of the same type are located within a single GWT Model. If PNAME is specified for a stress package, then PNAME will be used in the flow budget table in the listing file; it will also be used for the text entry in the cell-by-cell budget file. PNAME is case insensitive and is stored in all upper case letters.
GWT	OC	OPTIONS	BUDGET	KEYWORD	keyword to specify that record corresponds to the budget.
GWT	OC	OPTIONS	FILEOUT	KEYWORD	keyword to specify that an output filename is expected next.
GWT	OC	OPTIONS	BUDGETFILE	STRING	name of the output file to write budget information.
GWT	OC	OPTIONS	BUDGETCSV	KEYWORD	keyword to specify that record corresponds to the budget CSV.
GWT	OC	OPTIONS	BUDGETCSVFILE	STRING	name of the comma-separated value (CSV) output file to write budget summary information. A budget summary record will be written to this file for each time step of the simulation.
GWT	OC	OPTIONS	CONCENTRATION	KEYWORD	keyword to specify that record corresponds to concentration.
GWT	OC	OPTIONS	CONCENTRATIONFILE	STRING	name of the output file to write conc information.
GWT	OC	OPTIONS	PRINT_FORMAT	KEYWORD	keyword to specify format for printing to the listing file.
GWT	OC	OPTIONS	COLUMNS	INTEGER	number of columns for writing data.
GWT	OC	OPTIONS	WIDTH	INTEGER	width for writing each number.
GWT	OC	OPTIONS	DIGITS	INTEGER	number of digits to use for writing a number.
GWT	OC	OPTIONS	FORMAT	STRING	write format can be EXPONENTIAL, FIXED, GENERAL, or SCIENTIFIC.
GWT	OC	PERIOD	IPER	INTEGER	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.
GWT	OC	PERIOD	SAVE	KEYWORD	keyword to indicate that information will be saved this stress period.
GWT	OC	PERIOD	PRINT	KEYWORD	keyword to indicate that information will be printed this stress period.
GWT	OC	PERIOD	RTYPE	STRING	type of information to save or print. Can be BUDGET or CONCENTRATION.
GWT	OC	PERIOD	OCSETTING	KEYSTRING	specifies the steps for which the data will be saved.
GWT	OC	PERIOD	ALL	KEYWORD	keyword to indicate save for all time steps in period.
GWT	OC	PERIOD	FIRST	KEYWORD	keyword to indicate save for first step in period. This keyword may be used in conjunction with other keywords to print or save results for multiple time steps.
GWT	OC	PERIOD	LAST	KEYWORD	keyword to indicate save for last step in period. This keyword may be used in conjunction with other keywords to print or save results for multiple time steps.
GWT	OC	PERIOD	FREQUENCY	INTEGER	save at the specified time step frequency. This keyword may be used in conjunction with other keywords to print or save results for multiple time steps.
GWT	OC	PERIOD	STEPS	INTEGER (<NSTP)	save for each step specified in STEPS. This keyword may be used in conjunction with other keywords to print or save results for multiple time steps.
GWT	SSM	OPTIONS	PRINT_FLOWS	KEYWORD	keyword to indicate that the list of SSM 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.
GWT	SSM	OPTIONS	SAVE_FLOWS	KEYWORD	keyword to indicate that SSM flow terms will be written to the file specified with ``BUDGET FILEOUT'' in Output Control.
GWT	SSM	SOURCES	PNAME	STRING	name of the flow package for which an auxiliary variable contains a source concentration. If this flow package is represented using an advanced transport package (SFT, LKT, MWT, or UZT), then the advanced transport package will override SSM terms specified here.
GWT	SSM	SOURCES	SRCTYPE	STRING	keyword indicating how concentration will be assigned for sources and sinks. Keyword must be specified as either AUX or AUXMIXED. For both options the user must provide an auxiliary variable in the corresponding flow package. The auxiliary variable must have the same name as the AUXNAME value that follows. If the AUX keyword is specified, then the auxiliary variable specified by the user will be assigned as the concentration value for groundwater sources (flows with a positive sign). For negative flow rates (sinks), groundwater will be withdrawn from the cell at the simulated concentration of the cell. The AUXMIXED option provides an alternative method for how to determine the concentration of sinks. If the cell concentration is larger than the user-specified auxiliary concentration, then the concentration of groundwater withdrawn from the cell will be assigned as the user-specified concentration. Alternatively, if the user-specified auxiliary concentration is larger than the cell concentration, then groundwater will be withdrawn at the cell concentration. Thus, the AUXMIXED option is designed to work with the Evapotranspiration (EVT) and Recharge (RCH) Packages where water may be withdrawn at a concentration that is less than the cell concentration.
GWT	SSM	SOURCES	AUXNAME	STRING	name of the auxiliary variable in the package PNAME. This auxiliary variable must exist and be specified by the user in that package. The values in this auxiliary variable will be used to set the concentration associated with the flows for that boundary package.
GWT	SSM	FILEINPUT	PNAME	STRING	name of the flow package for which an SPC6 input file contains a source concentration. If this flow package is represented using an advanced transport package (SFT, LKT, MWT, or UZT), then the advanced transport package will override SSM terms specified here.
GWT	SSM	FILEINPUT	SPC6	KEYWORD	keyword to specify that record corresponds to a source sink mixing input file.
GWT	SSM	FILEINPUT	FILEIN	KEYWORD	keyword to specify that an input filename is expected next.
GWT	SSM	FILEINPUT	SPC6_FILENAME	STRING	character string that defines the path and filename for the file containing source and sink input data for the flow package. The SPC6_FILENAME file is a flexible input file that allows concentrations to be specified by stress period and with time series. Instructions for creating the SPC6_FILENAME input file are provided in the next section on file input for boundary concentrations.
GWT	SSM	FILEINPUT	MIXED	KEYWORD	keyword to specify that these stress package boundaries will have the mixed condition. The MIXED condition is described in the SOURCES block for AUXMIXED. The MIXED condition allows for water to be withdrawn at a concentration that is less than the cell concentration. It is intended primarily for representing evapotranspiration.
GWT	SRC	OPTIONS	AUXILIARY	STRING (NAUX)	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.
GWT	SRC	OPTIONS	AUXMULTNAME	STRING	name of auxiliary variable to be used as multiplier of mass loading rate.
GWT	SRC	OPTIONS	BOUNDNAMES	KEYWORD	keyword to indicate that boundary names may be provided with the list of mass source cells.
GWT	SRC	OPTIONS	PRINT_INPUT	KEYWORD	keyword to indicate that the list of mass source information will be written to the listing file immediately after it is read.
GWT	SRC	OPTIONS	PRINT_FLOWS	KEYWORD	keyword to indicate that the list of mass source 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.
GWT	SRC	OPTIONS	SAVE_FLOWS	KEYWORD	keyword to indicate that mass source flow terms will be written to the file specified with ``BUDGET FILEOUT'' in Output Control.
GWT	SRC	OPTIONS	TS6	KEYWORD	keyword to specify that record corresponds to a time-series file.
GWT	SRC	OPTIONS	FILEIN	KEYWORD	keyword to specify that an input filename is expected next.
GWT	SRC	OPTIONS	TS6_FILENAME	STRING	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.
GWT	SRC	OPTIONS	OBS6	KEYWORD	keyword to specify that record corresponds to an observations file.
GWT	SRC	OPTIONS	OBS6_FILENAME	STRING	name of input file to define observations for the Mass Source package. See the ``Observation utility'' section for instructions for preparing observation input files. Tables \ref{table:gwf-obstypetable} and \ref{table:gwt-obstypetable} lists observation type(s) supported by the Mass Source package.
GWT	SRC	DIMENSIONS	MAXBOUND	INTEGER	integer value specifying the maximum number of sources cells that will be specified for use during any stress period.
GWT	SRC	PERIOD	IPER	INTEGER	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.
GWT	SRC	PERIOD	CELLID	INTEGER (NCELLDIM)	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.
GWT	SRC	PERIOD	SMASSRATE	DOUBLE PRECISION	is the mass source loading rate. A positive value indicates addition of solute mass and a negative value indicates removal of solute mass. 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.
GWT	SRC	PERIOD	AUX	DOUBLE PRECISION (NAUX)	represents the values of the auxiliary variables for each mass source. The values of auxiliary variables must be present for each mass source. 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.
GWT	SRC	PERIOD	BOUNDNAME	STRING	name of the mass source 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.
GWT	MST	OPTIONS	SAVE_FLOWS	KEYWORD	keyword to indicate that MST flow terms will be written to the file specified with ``BUDGET FILEOUT'' in Output Control.
GWT	MST	OPTIONS	FIRST_ORDER_DECAY	KEYWORD	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.
GWT	MST	OPTIONS	ZERO_ORDER_DECAY	KEYWORD	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.
GWT	MST	OPTIONS	SORPTION	STRING	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.
GWT	MST	GRIDDATA	POROSITY	DOUBLE PRECISION (NODES)	is the mobile domain porosity, defined as the mobile domain pore volume per mobile domain volume. Additional information on porosity within the context of mobile and immobile domain transport simulations is included in the MODFLOW 6 Supplemental Technical Information document.
GWT	MST	GRIDDATA	DECAY	DOUBLE PRECISION (NODES)	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.
GWT	MST	GRIDDATA	DECAY_SORBED	DOUBLE PRECISION (NODES)	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.
GWT	MST	GRIDDATA	BULK_DENSITY	DOUBLE PRECISION (NODES)	is the bulk density of the aquifer in mass per length cubed. bulk_density is not required unless the SORPTION keyword is specified. Bulk density is defined as the mobile domain solid mass per mobile domain volume. Additional information on bulk density is included in the MODFLOW 6 Supplemental Technical Information document.
GWT	MST	GRIDDATA	DISTCOEF	DOUBLE PRECISION (NODES)	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.
GWT	MST	GRIDDATA	SP2	DOUBLE PRECISION (NODES)	is the exponent for the Freundlich isotherm and the sorption capacity for the Langmuir isotherm.
GWT	IST	OPTIONS	SAVE_FLOWS	KEYWORD	keyword to indicate that IST flow terms will be written to the file specified with ``BUDGET FILEOUT'' in Output Control.
GWT	IST	OPTIONS	BUDGET	KEYWORD	keyword to specify that record corresponds to the budget.
GWT	IST	OPTIONS	FILEOUT	KEYWORD	keyword to specify that an output filename is expected next.
GWT	IST	OPTIONS	BUDGETFILE	STRING	name of the binary output file to write budget information.
GWT	IST	OPTIONS	BUDGETCSV	KEYWORD	keyword to specify that record corresponds to the budget CSV.
GWT	IST	OPTIONS	BUDGETCSVFILE	STRING	name of the comma-separated value (CSV) output file to write budget summary information. A budget summary record will be written to this file for each time step of the simulation.
GWT	IST	OPTIONS	SORPTION	KEYWORD	is a text keyword to indicate that sorption will be activated. Use of this keyword requires that BULK_DENSITY and DISTCOEF are specified in the GRIDDATA block. The linear sorption isotherm is the only isotherm presently supported in the IST Package.
GWT	IST	OPTIONS	FIRST_ORDER_DECAY	KEYWORD	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.
GWT	IST	OPTIONS	ZERO_ORDER_DECAY	KEYWORD	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.
GWT	IST	OPTIONS	CIM	KEYWORD	keyword to specify that record corresponds to immobile concentration.
GWT	IST	OPTIONS	CIMFILE	STRING	name of the output file to write immobile concentrations. This file is a binary file that has the same format and structure as a binary head and concentration file. The value for the text variable written to the file is CIM. Immobile domain concentrations will be written to this file at the same interval as mobile domain concentrations are saved, as specified in the GWT Model Output Control file.
GWT	IST	OPTIONS	PRINT_FORMAT	KEYWORD	keyword to specify format for printing to the listing file.
GWT	IST	OPTIONS	COLUMNS	INTEGER	number of columns for writing data.
GWT	IST	OPTIONS	WIDTH	INTEGER	width for writing each number.
GWT	IST	OPTIONS	DIGITS	INTEGER	number of digits to use for writing a number.
GWT	IST	OPTIONS	FORMAT	STRING	write format can be EXPONENTIAL, FIXED, GENERAL, or SCIENTIFIC.
GWT	IST	GRIDDATA	POROSITY	DOUBLE PRECISION (NODES)	porosity of the immobile domain specified as the immobile domain pore volume per immobile domain volume.
GWT	IST	GRIDDATA	VOLFRAC	DOUBLE PRECISION (NODES)	fraction of the cell volume that consists of this immobile domain. The sum of all immobile domain volume fractions must be less than one.
GWT	IST	GRIDDATA	ZETAIM	DOUBLE PRECISION (NODES)	mass transfer rate coefficient between the mobile and immobile domains, in dimensions of per time.
GWT	IST	GRIDDATA	CIM	DOUBLE PRECISION (NODES)	initial concentration of the immobile domain in mass per length cubed. If CIM is not specified, then it is assumed to be zero.
GWT	IST	GRIDDATA	DECAY	DOUBLE PRECISION (NODES)	is the rate coefficient for first or zero-order decay for the aqueous phase of the immobile 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.
GWT	IST	GRIDDATA	DECAY_SORBED	DOUBLE PRECISION (NODES)	is the rate coefficient for first or zero-order decay for the sorbed phase of the immobile 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.
GWT	IST	GRIDDATA	BULK_DENSITY	DOUBLE PRECISION (NODES)	is the bulk density of this immobile domain in mass per length cubed. Bulk density is defined as the immobile domain solid mass per volume of the immobile domain. bulk_density is not required unless the SORPTION keyword is specified in the options block. If the SORPTION keyword is not specified in the options block, bulk_density will have no effect on simulation results.
GWT	IST	GRIDDATA	DISTCOEF	DOUBLE PRECISION (NODES)	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 in the options block. If the SORPTION keyword is not specified in the options block, distcoef will have no effect on simulation results.
GWT	SFT	OPTIONS	FLOW_PACKAGE_NAME	STRING	keyword to specify the name of the corresponding flow package. If not specified, then the corresponding flow package must have the same name as this advanced transport package (the name associated with this package in the GWT name file).
GWT	SFT	OPTIONS	AUXILIARY	STRING (NAUX)	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.
GWT	SFT	OPTIONS	FLOW_PACKAGE_AUXILIARY_NAME	STRING	keyword to specify the name of an auxiliary variable in the corresponding flow package. If specified, then the simulated concentrations from this advanced transport package will be copied into the auxiliary variable specified with this name. Note that the flow package must have an auxiliary variable with this name or the program will terminate with an error. If the flows for this advanced transport package are read from a file, then this option will have no effect.
GWT	SFT	OPTIONS	BOUNDNAMES	KEYWORD	keyword to indicate that boundary names may be provided with the list of reach cells.
GWT	SFT	OPTIONS	PRINT_INPUT	KEYWORD	keyword to indicate that the list of reach information will be written to the listing file immediately after it is read.
GWT	SFT	OPTIONS	PRINT_CONCENTRATION	KEYWORD	keyword to indicate that the list of reach concentration will be printed to the listing file for every stress period in which ``CONCENTRATION PRINT'' is specified in Output Control. If there is no Output Control option and PRINT_CONCENTRATION is specified, then concentration are printed for the last time step of each stress period.
GWT	SFT	OPTIONS	PRINT_FLOWS	KEYWORD	keyword to indicate that the list of reach 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.
GWT	SFT	OPTIONS	SAVE_FLOWS	KEYWORD	keyword to indicate that reach flow terms will be written to the file specified with ``BUDGET FILEOUT'' in Output Control.
GWT	SFT	OPTIONS	CONCENTRATION	KEYWORD	keyword to specify that record corresponds to concentration.
GWT	SFT	OPTIONS	CONCFILE	STRING	name of the binary output file to write concentration information.
GWT	SFT	OPTIONS	BUDGET	KEYWORD	keyword to specify that record corresponds to the budget.
GWT	SFT	OPTIONS	FILEOUT	KEYWORD	keyword to specify that an output filename is expected next.
GWT	SFT	OPTIONS	BUDGETFILE	STRING	name of the binary output file to write budget information.
GWT	SFT	OPTIONS	BUDGETCSV	KEYWORD	keyword to specify that record corresponds to the budget CSV.
GWT	SFT	OPTIONS	BUDGETCSVFILE	STRING	name of the comma-separated value (CSV) output file to write budget summary information. A budget summary record will be written to this file for each time step of the simulation.
GWT	SFT	OPTIONS	TS6	KEYWORD	keyword to specify that record corresponds to a time-series file.
GWT	SFT	OPTIONS	FILEIN	KEYWORD	keyword to specify that an input filename is expected next.
GWT	SFT	OPTIONS	TS6_FILENAME	STRING	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.
GWT	SFT	OPTIONS	OBS6	KEYWORD	keyword to specify that record corresponds to an observations file.
GWT	SFT	OPTIONS	OBS6_FILENAME	STRING	name of input file to define observations for the SFT package. See the ``Observation utility'' section for instructions for preparing observation input files. Tables \ref{table:gwf-obstypetable} and \ref{table:gwt-obstypetable} lists observation type(s) supported by the SFT package.
GWT	SFT	PACKAGEDATA	IFNO	INTEGER	integer value that defines the feature (reach) number associated with the specified PACKAGEDATA data on the line. IFNO must be greater than zero and less than or equal to NREACHES. Reach information must be specified for every reach or the program will terminate with an error. The program will also terminate with an error if information for a reach is specified more than once.
GWT	SFT	PACKAGEDATA	STRT	DOUBLE PRECISION	real value that defines the starting concentration for the reach.
GWT	SFT	PACKAGEDATA	AUX	DOUBLE PRECISION (NAUX)	represents the values of the auxiliary variables for each reach. The values of auxiliary variables must be present for each reach. 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.
GWT	SFT	PACKAGEDATA	BOUNDNAME	STRING	name of the reach 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.
GWT	SFT	PERIOD	IPER	INTEGER	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.
GWT	SFT	PERIOD	IFNO	INTEGER	integer value that defines the feature (reach) number associated with the specified PERIOD data on the line. IFNO must be greater than zero and less than or equal to NREACHES.
GWT	SFT	PERIOD	REACHSETTING	KEYSTRING	line of information that is parsed into a keyword and values. Keyword values that can be used to start the REACHSETTING string include: STATUS, CONCENTRATION, RAINFALL, EVAPORATION, RUNOFF, and AUXILIARY. These settings are used to assign the concentration of associated with the corresponding flow terms. Concentrations cannot be specified for all flow terms. For example, the Streamflow Package supports a ``DIVERSION'' flow term. Diversion water will be routed using the calculated concentration of the reach.
GWT	SFT	PERIOD	STATUS	STRING	keyword option to define reach status. STATUS can be ACTIVE, INACTIVE, or CONSTANT. By default, STATUS is ACTIVE, which means that concentration will be calculated for the reach. If a reach is inactive, then there will be no solute mass fluxes into or out of the reach and the inactive value will be written for the reach concentration. If a reach is constant, then the concentration for the reach will be fixed at the user specified value.
GWT	SFT	PERIOD	CONCENTRATION	STRING	real or character value that defines the concentration for the reach. The specified CONCENTRATION is only applied if the reach is a constant concentration reach. 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.
GWT	SFT	PERIOD	RAINFALL	STRING	real or character value that defines the rainfall solute concentration $(ML^{-3})$ for the reach. 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.
GWT	SFT	PERIOD	EVAPORATION	STRING	real or character value that defines the concentration of evaporated water $(ML^{-3})$ for the reach. If this concentration value is larger than the simulated concentration in the reach, then the evaporated water will be removed at the same concentration as the reach. 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.
GWT	SFT	PERIOD	RUNOFF	STRING	real or character value that defines the concentration of runoff $(ML^{-3})$ for the reach. Value must be greater than or equal to zero. 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.
GWT	SFT	PERIOD	INFLOW	STRING	real or character value that defines the concentration of inflow $(ML^{-3})$ for the reach. Value must be greater than or equal to zero. 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.
GWT	SFT	PERIOD	AUXILIARY	KEYWORD	keyword for specifying auxiliary variable.
GWT	SFT	PERIOD	AUXNAME	STRING	name for the auxiliary variable to be assigned AUXVAL. AUXNAME must match one of the auxiliary variable names defined in the OPTIONS block. If AUXNAME does not match one of the auxiliary variable names defined in the OPTIONS block the data are ignored.
GWT	SFT	PERIOD	AUXVAL	DOUBLE PRECISION	value for the auxiliary variable. 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.
GWT	LKT	OPTIONS	FLOW_PACKAGE_NAME	STRING	keyword to specify the name of the corresponding flow package. If not specified, then the corresponding flow package must have the same name as this advanced transport package (the name associated with this package in the GWT name file).
GWT	LKT	OPTIONS	AUXILIARY	STRING (NAUX)	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.
GWT	LKT	OPTIONS	FLOW_PACKAGE_AUXILIARY_NAME	STRING	keyword to specify the name of an auxiliary variable in the corresponding flow package. If specified, then the simulated concentrations from this advanced transport package will be copied into the auxiliary variable specified with this name. Note that the flow package must have an auxiliary variable with this name or the program will terminate with an error. If the flows for this advanced transport package are read from a file, then this option will have no effect.
GWT	LKT	OPTIONS	BOUNDNAMES	KEYWORD	keyword to indicate that boundary names may be provided with the list of lake cells.
GWT	LKT	OPTIONS	PRINT_INPUT	KEYWORD	keyword to indicate that the list of lake information will be written to the listing file immediately after it is read.
GWT	LKT	OPTIONS	PRINT_CONCENTRATION	KEYWORD	keyword to indicate that the list of lake concentration will be printed to the listing file for every stress period in which ``CONCENTRATION PRINT'' is specified in Output Control. If there is no Output Control option and PRINT_CONCENTRATION is specified, then concentration are printed for the last time step of each stress period.
GWT	LKT	OPTIONS	PRINT_FLOWS	KEYWORD	keyword to indicate that the list of lake 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.
GWT	LKT	OPTIONS	SAVE_FLOWS	KEYWORD	keyword to indicate that lake flow terms will be written to the file specified with ``BUDGET FILEOUT'' in Output Control.
GWT	LKT	OPTIONS	CONCENTRATION	KEYWORD	keyword to specify that record corresponds to concentration.
GWT	LKT	OPTIONS	CONCFILE	STRING	name of the binary output file to write concentration information.
GWT	LKT	OPTIONS	BUDGET	KEYWORD	keyword to specify that record corresponds to the budget.
GWT	LKT	OPTIONS	FILEOUT	KEYWORD	keyword to specify that an output filename is expected next.
GWT	LKT	OPTIONS	BUDGETFILE	STRING	name of the binary output file to write budget information.
GWT	LKT	OPTIONS	BUDGETCSV	KEYWORD	keyword to specify that record corresponds to the budget CSV.
GWT	LKT	OPTIONS	BUDGETCSVFILE	STRING	name of the comma-separated value (CSV) output file to write budget summary information. A budget summary record will be written to this file for each time step of the simulation.
GWT	LKT	OPTIONS	TS6	KEYWORD	keyword to specify that record corresponds to a time-series file.
GWT	LKT	OPTIONS	FILEIN	KEYWORD	keyword to specify that an input filename is expected next.
GWT	LKT	OPTIONS	TS6_FILENAME	STRING	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.
GWT	LKT	OPTIONS	OBS6	KEYWORD	keyword to specify that record corresponds to an observations file.
GWT	LKT	OPTIONS	OBS6_FILENAME	STRING	name of input file to define observations for the LKT package. See the ``Observation utility'' section for instructions for preparing observation input files. Tables \ref{table:gwf-obstypetable} and \ref{table:gwt-obstypetable} lists observation type(s) supported by the LKT package.
GWT	LKT	PACKAGEDATA	IFNO	INTEGER	integer value that defines the feature (lake) number associated with the specified PACKAGEDATA data on the line. IFNO must be greater than zero and less than or equal to NLAKES. Lake information must be specified for every lake or the program will terminate with an error. The program will also terminate with an error if information for a lake is specified more than once.
GWT	LKT	PACKAGEDATA	STRT	DOUBLE PRECISION	real value that defines the starting concentration for the lake.
GWT	LKT	PACKAGEDATA	AUX	DOUBLE PRECISION (NAUX)	represents the values of the auxiliary variables for each lake. The values of auxiliary variables must be present for each lake. 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.
GWT	LKT	PACKAGEDATA	BOUNDNAME	STRING	name of the lake 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.
GWT	LKT	PERIOD	IPER	INTEGER	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.
GWT	LKT	PERIOD	IFNO	INTEGER	integer value that defines the feature (lake) number associated with the specified PERIOD data on the line. IFNO must be greater than zero and less than or equal to NLAKES.
GWT	LKT	PERIOD	LAKSETTING	KEYSTRING	line of information that is parsed into a keyword and values. Keyword values that can be used to start the LAKSETTING string include: STATUS, CONCENTRATION, RAINFALL, EVAPORATION, RUNOFF, and AUXILIARY. These settings are used to assign the concentration of associated with the corresponding flow terms. Concentrations cannot be specified for all flow terms. For example, the Lake Package supports a ``WITHDRAWAL'' flow term. If this withdrawal term is active, then water will be withdrawn from the lake at the calculated concentration of the lake.
GWT	LKT	PERIOD	STATUS	STRING	keyword option to define lake status. STATUS can be ACTIVE, INACTIVE, or CONSTANT. By default, STATUS is ACTIVE, which means that concentration will be calculated for the lake. If a lake is inactive, then there will be no solute mass fluxes into or out of the lake and the inactive value will be written for the lake concentration. If a lake is constant, then the concentration for the lake will be fixed at the user specified value.
GWT	LKT	PERIOD	CONCENTRATION	STRING	real or character value that defines the concentration for the lake. The specified CONCENTRATION is only applied if the lake is a constant concentration lake. 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.
GWT	LKT	PERIOD	RAINFALL	STRING	real or character value that defines the rainfall solute concentration $(ML^{-3})$ for the lake. 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.
GWT	LKT	PERIOD	EVAPORATION	STRING	real or character value that defines the concentration of evaporated water $(ML^{-3})$ for the lake. If this concentration value is larger than the simulated concentration in the lake, then the evaporated water will be removed at the same concentration as the lake. 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.
GWT	LKT	PERIOD	RUNOFF	STRING	real or character value that defines the concentration of runoff $(ML^{-3})$ for the lake. Value must be greater than or equal to zero. 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.
GWT	LKT	PERIOD	EXT-INFLOW	STRING	real or character value that defines the concentration of external inflow $(ML^{-3})$ for the lake. Value must be greater than or equal to zero. 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.
GWT	LKT	PERIOD	AUXILIARY	KEYWORD	keyword for specifying auxiliary variable.
GWT	LKT	PERIOD	AUXNAME	STRING	name for the auxiliary variable to be assigned AUXVAL. AUXNAME must match one of the auxiliary variable names defined in the OPTIONS block. If AUXNAME does not match one of the auxiliary variable names defined in the OPTIONS block the data are ignored.
GWT	LKT	PERIOD	AUXVAL	DOUBLE PRECISION	value for the auxiliary variable. 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.
GWT	MWT	OPTIONS	FLOW_PACKAGE_NAME	STRING	keyword to specify the name of the corresponding flow package. If not specified, then the corresponding flow package must have the same name as this advanced transport package (the name associated with this package in the GWT name file).
GWT	MWT	OPTIONS	AUXILIARY	STRING (NAUX)	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.
GWT	MWT	OPTIONS	FLOW_PACKAGE_AUXILIARY_NAME	STRING	keyword to specify the name of an auxiliary variable in the corresponding flow package. If specified, then the simulated concentrations from this advanced transport package will be copied into the auxiliary variable specified with this name. Note that the flow package must have an auxiliary variable with this name or the program will terminate with an error. If the flows for this advanced transport package are read from a file, then this option will have no effect.
GWT	MWT	OPTIONS	BOUNDNAMES	KEYWORD	keyword to indicate that boundary names may be provided with the list of well cells.
GWT	MWT	OPTIONS	PRINT_INPUT	KEYWORD	keyword to indicate that the list of well information will be written to the listing file immediately after it is read.
GWT	MWT	OPTIONS	PRINT_CONCENTRATION	KEYWORD	keyword to indicate that the list of well concentration will be printed to the listing file for every stress period in which ``CONCENTRATION PRINT'' is specified in Output Control. If there is no Output Control option and PRINT_CONCENTRATION is specified, then concentration are printed for the last time step of each stress period.
GWT	MWT	OPTIONS	PRINT_FLOWS	KEYWORD	keyword to indicate that the list of well 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.
GWT	MWT	OPTIONS	SAVE_FLOWS	KEYWORD	keyword to indicate that well flow terms will be written to the file specified with ``BUDGET FILEOUT'' in Output Control.
GWT	MWT	OPTIONS	CONCENTRATION	KEYWORD	keyword to specify that record corresponds to concentration.
GWT	MWT	OPTIONS	CONCFILE	STRING	name of the binary output file to write concentration information.
GWT	MWT	OPTIONS	BUDGET	KEYWORD	keyword to specify that record corresponds to the budget.
GWT	MWT	OPTIONS	FILEOUT	KEYWORD	keyword to specify that an output filename is expected next.
GWT	MWT	OPTIONS	BUDGETFILE	STRING	name of the binary output file to write budget information.
GWT	MWT	OPTIONS	BUDGETCSV	KEYWORD	keyword to specify that record corresponds to the budget CSV.
GWT	MWT	OPTIONS	BUDGETCSVFILE	STRING	name of the comma-separated value (CSV) output file to write budget summary information. A budget summary record will be written to this file for each time step of the simulation.
GWT	MWT	OPTIONS	TS6	KEYWORD	keyword to specify that record corresponds to a time-series file.
GWT	MWT	OPTIONS	FILEIN	KEYWORD	keyword to specify that an input filename is expected next.
GWT	MWT	OPTIONS	TS6_FILENAME	STRING	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.
GWT	MWT	OPTIONS	OBS6	KEYWORD	keyword to specify that record corresponds to an observations file.
GWT	MWT	OPTIONS	OBS6_FILENAME	STRING	name of input file to define observations for the MWT package. See the ``Observation utility'' section for instructions for preparing observation input files. Tables \ref{table:gwf-obstypetable} and \ref{table:gwt-obstypetable} lists observation type(s) supported by the MWT package.
GWT	MWT	PACKAGEDATA	IFNO	INTEGER	integer value that defines the feature (well) number associated with the specified PACKAGEDATA data on the line. IFNO must be greater than zero and less than or equal to NMAWWELLS. Well information must be specified for every well or the program will terminate with an error. The program will also terminate with an error if information for a well is specified more than once.
GWT	MWT	PACKAGEDATA	STRT	DOUBLE PRECISION	real value that defines the starting concentration for the well.
GWT	MWT	PACKAGEDATA	AUX	DOUBLE PRECISION (NAUX)	represents the values of the auxiliary variables for each well. The values of auxiliary variables must be present for each well. 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.
GWT	MWT	PACKAGEDATA	BOUNDNAME	STRING	name of the well 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.
GWT	MWT	PERIOD	IPER	INTEGER	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.
GWT	MWT	PERIOD	IFNO	INTEGER	integer value that defines the feature (well) number associated with the specified PERIOD data on the line. IFNO must be greater than zero and less than or equal to NMAWWELLS.
GWT	MWT	PERIOD	MWTSETTING	KEYSTRING	line of information that is parsed into a keyword and values. Keyword values that can be used to start the MWTSETTING string include: STATUS, CONCENTRATION, RAINFALL, EVAPORATION, RUNOFF, and AUXILIARY. These settings are used to assign the concentration associated with the corresponding flow terms. Concentrations cannot be specified for all flow terms. For example, the Multi-Aquifer Well Package supports a ``WITHDRAWAL'' flow term. If this withdrawal term is active, then water will be withdrawn from the well at the calculated concentration of the well.
GWT	MWT	PERIOD	STATUS	STRING	keyword option to define well status. STATUS can be ACTIVE, INACTIVE, or CONSTANT. By default, STATUS is ACTIVE, which means that concentration will be calculated for the well. If a well is inactive, then there will be no solute mass fluxes into or out of the well and the inactive value will be written for the well concentration. If a well is constant, then the concentration for the well will be fixed at the user specified value.
GWT	MWT	PERIOD	CONCENTRATION	STRING	real or character value that defines the concentration for the well. The specified CONCENTRATION is only applied if the well is a constant concentration well. 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.
GWT	MWT	PERIOD	RATE	STRING	real or character value that defines the injection solute concentration $(ML^{-3})$ for the well. 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.
GWT	MWT	PERIOD	AUXILIARY	KEYWORD	keyword for specifying auxiliary variable.
GWT	MWT	PERIOD	AUXNAME	STRING	name for the auxiliary variable to be assigned AUXVAL. AUXNAME must match one of the auxiliary variable names defined in the OPTIONS block. If AUXNAME does not match one of the auxiliary variable names defined in the OPTIONS block the data are ignored.
GWT	MWT	PERIOD	AUXVAL	DOUBLE PRECISION	value for the auxiliary variable. 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.
GWT	UZT	OPTIONS	FLOW_PACKAGE_NAME	STRING	keyword to specify the name of the corresponding flow package. If not specified, then the corresponding flow package must have the same name as this advanced transport package (the name associated with this package in the GWT name file).
GWT	UZT	OPTIONS	AUXILIARY	STRING (NAUX)	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.
GWT	UZT	OPTIONS	FLOW_PACKAGE_AUXILIARY_NAME	STRING	keyword to specify the name of an auxiliary variable in the corresponding flow package. If specified, then the simulated concentrations from this advanced transport package will be copied into the auxiliary variable specified with this name. Note that the flow package must have an auxiliary variable with this name or the program will terminate with an error. If the flows for this advanced transport package are read from a file, then this option will have no effect.
GWT	UZT	OPTIONS	BOUNDNAMES	KEYWORD	keyword to indicate that boundary names may be provided with the list of unsaturated zone flow cells.
GWT	UZT	OPTIONS	PRINT_INPUT	KEYWORD	keyword to indicate that the list of unsaturated zone flow information will be written to the listing file immediately after it is read.
GWT	UZT	OPTIONS	PRINT_CONCENTRATION	KEYWORD	keyword to indicate that the list of UZF cell concentration will be printed to the listing file for every stress period in which ``CONCENTRATION PRINT'' is specified in Output Control. If there is no Output Control option and PRINT_CONCENTRATION is specified, then concentration are printed for the last time step of each stress period.
GWT	UZT	OPTIONS	PRINT_FLOWS	KEYWORD	keyword to indicate that the list of unsaturated zone 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.
GWT	UZT	OPTIONS	SAVE_FLOWS	KEYWORD	keyword to indicate that unsaturated zone flow terms will be written to the file specified with ``BUDGET FILEOUT'' in Output Control.
GWT	UZT	OPTIONS	CONCENTRATION	KEYWORD	keyword to specify that record corresponds to concentration.
GWT	UZT	OPTIONS	CONCFILE	STRING	name of the binary output file to write concentration information.
GWT	UZT	OPTIONS	BUDGET	KEYWORD	keyword to specify that record corresponds to the budget.
GWT	UZT	OPTIONS	FILEOUT	KEYWORD	keyword to specify that an output filename is expected next.
GWT	UZT	OPTIONS	BUDGETFILE	STRING	name of the binary output file to write budget information.
GWT	UZT	OPTIONS	BUDGETCSV	KEYWORD	keyword to specify that record corresponds to the budget CSV.
GWT	UZT	OPTIONS	BUDGETCSVFILE	STRING	name of the comma-separated value (CSV) output file to write budget summary information. A budget summary record will be written to this file for each time step of the simulation.
GWT	UZT	OPTIONS	TS6	KEYWORD	keyword to specify that record corresponds to a time-series file.
GWT	UZT	OPTIONS	FILEIN	KEYWORD	keyword to specify that an input filename is expected next.
GWT	UZT	OPTIONS	TS6_FILENAME	STRING	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.
GWT	UZT	OPTIONS	OBS6	KEYWORD	keyword to specify that record corresponds to an observations file.
GWT	UZT	OPTIONS	OBS6_FILENAME	STRING	name of input file to define observations for the UZT package. See the ``Observation utility'' section for instructions for preparing observation input files. Tables \ref{table:gwf-obstypetable} and \ref{table:gwt-obstypetable} lists observation type(s) supported by the UZT package.
GWT	UZT	PACKAGEDATA	IFNO	INTEGER	integer value that defines the feature (UZF object) number associated with the specified PACKAGEDATA data on the line. IFNO must be greater than zero and less than or equal to NUZFCELLS. Unsaturated zone flow information must be specified for every UZF cell or the program will terminate with an error. The program will also terminate with an error if information for a UZF cell is specified more than once.
GWT	UZT	PACKAGEDATA	STRT	DOUBLE PRECISION	real value that defines the starting concentration for the unsaturated zone flow cell.
GWT	UZT	PACKAGEDATA	AUX	DOUBLE PRECISION (NAUX)	represents the values of the auxiliary variables for each unsaturated zone flow. The values of auxiliary variables must be present for each unsaturated zone flow. 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.
GWT	UZT	PACKAGEDATA	BOUNDNAME	STRING	name of the unsaturated zone flow 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.
GWT	UZT	PERIOD	IPER	INTEGER	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.
GWT	UZT	PERIOD	IFNO	INTEGER	integer value that defines the feature (UZF object) number associated with the specified PERIOD data on the line. IFNO must be greater than zero and less than or equal to NUZFCELLS.
GWT	UZT	PERIOD	UZTSETTING	KEYSTRING	line of information that is parsed into a keyword and values. Keyword values that can be used to start the UZTSETTING string include: STATUS, CONCENTRATION, INFILTRATION, UZET, and AUXILIARY. These settings are used to assign the concentration of associated with the corresponding flow terms. Concentrations cannot be specified for all flow terms.
GWT	UZT	PERIOD	STATUS	STRING	keyword option to define UZF cell status. STATUS can be ACTIVE, INACTIVE, or CONSTANT. By default, STATUS is ACTIVE, which means that concentration will be calculated for the UZF cell. If a UZF cell is inactive, then there will be no solute mass fluxes into or out of the UZF cell and the inactive value will be written for the UZF cell concentration. If a UZF cell is constant, then the concentration for the UZF cell will be fixed at the user specified value.
GWT	UZT	PERIOD	CONCENTRATION	STRING	real or character value that defines the concentration for the unsaturated zone flow cell. The specified CONCENTRATION is only applied if the unsaturated zone flow cell is a constant concentration cell. 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.
GWT	UZT	PERIOD	INFILTRATION	STRING	real or character value that defines the infiltration solute concentration $(ML^{-3})$ for the UZF cell. 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.
GWT	UZT	PERIOD	UZET	STRING	real or character value that defines the concentration of unsaturated zone evapotranspiration water $(ML^{-3})$ for the UZF cell. If this concentration value is larger than the simulated concentration in the UZF cell, then the unsaturated zone ET water will be removed at the same concentration as the UZF cell. 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.
GWT	UZT	PERIOD	AUXILIARY	KEYWORD	keyword for specifying auxiliary variable.
GWT	UZT	PERIOD	AUXNAME	STRING	name for the auxiliary variable to be assigned AUXVAL. AUXNAME must match one of the auxiliary variable names defined in the OPTIONS block. If AUXNAME does not match one of the auxiliary variable names defined in the OPTIONS block the data are ignored.
GWT	UZT	PERIOD	AUXVAL	DOUBLE PRECISION	value for the auxiliary variable. 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.
GWT	FMI	OPTIONS	SAVE_FLOWS	KEYWORD	keyword to indicate that FMI flow terms will be written to the file specified with ``BUDGET FILEOUT'' in Output Control.
GWT	FMI	OPTIONS	FLOW_IMBALANCE_CORRECTION	KEYWORD	correct for an imbalance in flows by assuming that any residual flow error comes in or leaves at the concentration of the cell. When this option is activated, the GWT Model budget written to the listing file will contain two additional entries: FLOW-ERROR and FLOW-CORRECTION. These two entries will be equal but opposite in sign. The FLOW-CORRECTION term is a mass flow that is added to offset the error caused by an imprecise flow balance. If these terms are not relatively small, the flow model should be rerun with stricter convergence tolerances.
GWT	FMI	PACKAGEDATA	FLOWTYPE	STRING	is the word GWFBUDGET, GWFHEAD, GWFMOVER or the name of an advanced GWF stress package. If GWFBUDGET is specified, then the corresponding file must be a budget file from a previous GWF Model run. If an advanced GWF stress package name appears then the corresponding file must be the budget file saved by a LAK, SFR, MAW or UZF Package.
GWT	FMI	PACKAGEDATA	FILEIN	KEYWORD	keyword to specify that an input filename is expected next.
GWT	FMI	PACKAGEDATA	FNAME	STRING	is the name of the file containing flows. The path to the file should be included if the file is not located in the folder where the program was run.
GWT	MVT	OPTIONS	PRINT_INPUT	KEYWORD	keyword to indicate that the list of mover information will be written to the listing file immediately after it is read.
GWT	MVT	OPTIONS	PRINT_FLOWS	KEYWORD	keyword to indicate that the list of lake 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.
GWT	MVT	OPTIONS	SAVE_FLOWS	KEYWORD	keyword to indicate that lake flow terms will be written to the file specified with ``BUDGET FILEOUT'' in Output Control.
GWT	MVT	OPTIONS	BUDGET	KEYWORD	keyword to specify that record corresponds to the budget.
GWT	MVT	OPTIONS	FILEOUT	KEYWORD	keyword to specify that an output filename is expected next.
GWT	MVT	OPTIONS	BUDGETFILE	STRING	name of the binary output file to write budget information.
GWT	MVT	OPTIONS	BUDGETCSV	KEYWORD	keyword to specify that record corresponds to the budget CSV.
GWT	MVT	OPTIONS	BUDGETCSVFILE	STRING	name of the comma-separated value (CSV) output file to write budget summary information. A budget summary record will be written to this file for each time step of the simulation.
GWT	API	OPTIONS	BOUNDNAMES	KEYWORD	keyword to indicate that boundary names may be provided with the list of api boundary cells.
GWT	API	OPTIONS	PRINT_INPUT	KEYWORD	keyword to indicate that the list of api boundary information will be written to the listing file immediately after it is read.
GWT	API	OPTIONS	PRINT_FLOWS	KEYWORD	keyword to indicate that the list of api boundary 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.
GWT	API	OPTIONS	SAVE_FLOWS	KEYWORD	keyword to indicate that api boundary flow terms will be written to the file specified with ``BUDGET FILEOUT'' in Output Control.
GWT	API	OPTIONS	OBS6	KEYWORD	keyword to specify that record corresponds to an observations file.
GWT	API	OPTIONS	FILEIN	KEYWORD	keyword to specify that an input filename is expected next.
GWT	API	OPTIONS	OBS6_FILENAME	STRING	name of input file to define observations for the api boundary package. See the ``Observation utility'' section for instructions for preparing observation input files. Tables \ref{table:gwf-obstypetable} and \ref{table:gwt-obstypetable} lists observation type(s) supported by the api boundary package.
GWT	API	OPTIONS	MOVER	KEYWORD	keyword to indicate that this instance of the api boundary Package can be used with the Water Mover (MVR) Package. When the MOVER option is specified, additional memory is allocated within the package to store the available, provided, and received water.
GWT	API	DIMENSIONS	MAXBOUND	INTEGER	integer value specifying the maximum number of api boundary cells that will be specified for use during any stress period.
UTL	SPC	OPTIONS	PRINT_INPUT	KEYWORD	keyword to indicate that the list of spc information will be written to the listing file immediately after it is read.
UTL	SPC	OPTIONS	TS6	KEYWORD	keyword to specify that record corresponds to a time-series file.
UTL	SPC	OPTIONS	FILEIN	KEYWORD	keyword to specify that an input filename is expected next.
UTL	SPC	OPTIONS	TS6_FILENAME	STRING	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.
UTL	SPC	DIMENSIONS	MAXBOUND	INTEGER	integer value specifying the maximum number of spc cells that will be specified for use during any stress period.
UTL	SPC	PERIOD	IPER	INTEGER	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.
UTL	SPC	PERIOD	BNDNO	INTEGER	integer value that defines the boundary package feature number associated with the specified PERIOD data on the line. BNDNO must be greater than zero and less than or equal to MAXBOUND.
UTL	SPC	PERIOD	SPCSETTING	KEYSTRING	line of information that is parsed into a keyword and values. Keyword values that can be used to start the MAWSETTING string include: CONCENTRATION.
UTL	SPC	PERIOD	CONCENTRATION	DOUBLE PRECISION	is the boundary concentration. 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. By default, the CONCENTRATION for each boundary feature is zero.
UTL	SPCA	OPTIONS	READASARRAYS	KEYWORD	indicates that array-based input will be used for the SPC Package. This keyword must be specified to use array-based input.
UTL	SPCA	OPTIONS	PRINT_INPUT	KEYWORD	keyword to indicate that the list of spc information will be written to the listing file immediately after it is read.
UTL	SPCA	OPTIONS	TAS6	KEYWORD	keyword to specify that record corresponds to a time-array-series file.
UTL	SPCA	OPTIONS	FILEIN	KEYWORD	keyword to specify that an input filename is expected next.
UTL	SPCA	OPTIONS	TAS6_FILENAME	STRING	defines a time-array-series file defining a time-array series that can be used to assign time-varying values. See the Time-Variable Input section for instructions on using the time-array series capability.
UTL	SPCA	PERIOD	IPER	INTEGER	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.
UTL	SPCA	PERIOD	CONCENTRATION	DOUBLE PRECISION (NCOL*NROW; NCPL)	is the concentration of the associated Recharge or Evapotranspiration stress package. The concentration array may be defined by a time-array series (see the "Using Time-Array Series in a Package" section).
UTL	OBS	OPTIONS	DIGITS	INTEGER	Keyword and an integer digits specifier used for conversion of simulated values to text on output. If not specified, the default is the maximum number of digits stored in the program (as written with the G0 Fortran specifier). When simulated values are written to a comma-separated value text file specified in a CONTINUOUS block below, the digits specifier controls the number of significant digits with which simulated values are written to the output file. The digits specifier has no effect on the number of significant digits with which the simulation time is written for continuous observations. If DIGITS is specified as zero, then observations are written with the default setting, which is the maximum number of digits.
UTL	OBS	OPTIONS	PRINT_INPUT	KEYWORD	keyword to indicate that the list of observation information will be written to the listing file immediately after it is read.
UTL	OBS	CONTINUOUS	FILEOUT	KEYWORD	keyword to specify that an output filename is expected next.
UTL	OBS	CONTINUOUS	OBS_OUTPUT_FILE_NAME	STRING	Name of a file to which simulated values corresponding to observations in the block are to be written. The file name can be an absolute or relative path name. A unique output file must be specified for each CONTINUOUS block. If the BINARY'' option is used, output is written in binary form. By convention, text output files have the extension csv'' (for Comma-Separated Values'') and binary output files have the extension bsv'' (for ``Binary Simulated Values'').
UTL	OBS	CONTINUOUS	BINARY	KEYWORD	an optional keyword used to indicate that the output file should be written in binary (unformatted) form.
UTL	OBS	CONTINUOUS	OBSNAME	STRING	string of 1 to 40 nonblank characters used to identify the observation. The identifier need not be unique; however, identification and post-processing of observations in the output files are facilitated if each observation is given a unique name.
UTL	OBS	CONTINUOUS	OBSTYPE	STRING	a string of characters used to identify the observation type.
UTL	OBS	CONTINUOUS	ID	STRING	Text identifying cell where observation is located. For packages other than NPF, if boundary names are defined in the corresponding package input file, ID can be a boundary name. Otherwise ID is a cellid. If the model discretization is type DIS, cellid is three integers (layer, row, column). If the discretization is DISV, cellid is two integers (layer, cell number). If the discretization is DISU, cellid is one integer (node number).
UTL	OBS	CONTINUOUS	ID2	STRING	Text identifying cell adjacent to cell identified by ID. The form of ID2 is as described for ID. ID2 is used for intercell-flow observations of a GWF model, for three observation types of the LAK Package, for two observation types of the MAW Package, and one observation type of the UZF Package.
UTL	LAKTAB	DIMENSIONS	NROW	INTEGER	integer value specifying the number of rows in the lake table. There must be NROW rows of data in the TABLE block.
UTL	LAKTAB	DIMENSIONS	NCOL	INTEGER	integer value specifying the number of columns in the lake table. There must be NCOL columns of data in the TABLE block. For lakes with HORIZONTAL and/or VERTICAL CTYPE connections, NCOL must be equal to 3. For lakes with EMBEDDEDH or EMBEDDEDV CTYPE connections, NCOL must be equal to 4.
UTL	LAKTAB	TABLE	STAGE	DOUBLE PRECISION	real value that defines the stage corresponding to the remaining data on the line.
UTL	LAKTAB	TABLE	VOLUME	DOUBLE PRECISION	real value that defines the lake volume corresponding to the stage specified on the line.
UTL	LAKTAB	TABLE	SAREA	DOUBLE PRECISION	real value that defines the lake surface area corresponding to the stage specified on the line.
UTL	LAKTAB	TABLE	BAREA	DOUBLE PRECISION	real value that defines the lake-GWF exchange area corresponding to the stage specified on the line. BAREA is only specified if the CLAKTYPE for the lake is EMBEDDEDH or EMBEDDEDV.
UTL	SFRTAB	DIMENSIONS	NROW	INTEGER	integer value specifying the number of rows in the reach cross-section table. There must be NROW rows of data in the TABLE block.
UTL	SFRTAB	DIMENSIONS	NCOL	INTEGER	integer value specifying the number of columns in the reach cross-section table. There must be NCOL columns of data in the TABLE block. NCOL must be equal to 2 if MANFRACTION is not specified or 3 otherwise.
UTL	SFRTAB	TABLE	XFRACTION	DOUBLE PRECISION	real value that defines the station (x) data for the cross-section as a fraction of the width (RWID) of the reach. XFRACTION must be greater than or equal to zero but can be greater than one. XFRACTION values can be used to decrease or increase the width of a reach from the specified reach width (RWID).
UTL	SFRTAB	TABLE	HEIGHT	DOUBLE PRECISION	real value that is the height relative to the top of the lowest elevation of the streambed (RTP) and corresponding to the station data on the same line. HEIGHT must be greater than or equal to zero and at least one cross-section height must be equal to zero.
UTL	SFRTAB	TABLE	MANFRACTION	DOUBLE PRECISION	real value that defines the Manning's roughness coefficient data for the cross-section as a fraction of the Manning's roughness coefficient for the reach (MAN) and corresponding to the station data on the same line. MANFRACTION must be greater than zero. MANFRACTION is applied from the XFRACTION value on the same line to the XFRACTION value on the next line. Although a MANFRACTION value is specified on the last line, any value greater than zero can be applied to MANFRACTION(NROW). MANFRACTION is only specified if NCOL is 3. If MANFRACTION is not specified, the Manning's roughness coefficient for the reach (MAN) is applied to the entire cross-section.
UTL	TS	ATTRIBUTES	NAMES	KEYWORD	xxx
UTL	TS	ATTRIBUTES	TIME_SERIES_NAMES	STRING ANY1D	Name by which a package references a particular time-array series. The name must be unique among all time-array series used in a package.
UTL	TS	ATTRIBUTES	METHODS	KEYWORD	xxx
UTL	TS	ATTRIBUTES	INTERPOLATION_METHOD	STRING TIME_SERIES_NAMES	Interpolation method, which is either STEPWISE or LINEAR.
UTL	TS	ATTRIBUTES	METHOD	KEYWORD	xxx
UTL	TS	ATTRIBUTES	INTERPOLATION_METHOD_SINGLE	STRING	Interpolation method, which is either STEPWISE or LINEAR.
UTL	TS	ATTRIBUTES	SFACS	KEYWORD	xxx
UTL	TS	ATTRIBUTES	SFACVAL	DOUBLE PRECISION <TIME_SERIES_NAME	Scale factor, which will multiply all array values in time series. SFAC is an optional attribute; if omitted, SFAC = 1.0.
UTL	TS	ATTRIBUTES	SFAC	KEYWORD	xxx
UTL	TS	TIMESERIES	TS_TIME	DOUBLE PRECISION	A numeric time relative to the start of the simulation, in the time unit used in the simulation. Times must be strictly increasing.
UTL	TS	TIMESERIES	TS_ARRAY	DOUBLE PRECISION TIME_SERIES_NAMES	A 2-D array of numeric, floating-point values, or a constant value, readable by the U2DREL array-reading utility.
UTL	TAS	ATTRIBUTES	NAME	KEYWORD	xxx
UTL	TAS	ATTRIBUTES	TIME_SERIES_NAME	STRING ANY1D	Name by which a package references a particular time-array series. The name must be unique among all time-array series used in a package.
UTL	TAS	ATTRIBUTES	METHOD	KEYWORD	xxx
UTL	TAS	ATTRIBUTES	INTERPOLATION_METHOD	STRING	Interpolation method, which is either STEPWISE or LINEAR.
UTL	TAS	ATTRIBUTES	SFAC	KEYWORD	xxx
UTL	TAS	ATTRIBUTES	SFACVAL	DOUBLE PRECISION TIME_SERIES_NAME	Scale factor, which will multiply all array values in time series. SFAC is an optional attribute; if omitted, SFAC = 1.0.
UTL	TAS	TIME	TIME_FROM_MODEL_START	DOUBLE PRECISION	A numeric time relative to the start of the simulation, in the time unit used in the simulation. Times must be strictly increasing.
UTL	TAS	TIME	TAS_ARRAY	DOUBLE PRECISION (UNKNOWN)	An array of numeric, floating-point values, or a constant value, readable by the U2DREL array-reading utility.
UTL	ATS	DIMENSIONS	MAXATS	INTEGER	is the number of records in the subsequent perioddata block that will be used for adaptive time stepping.
UTL	ATS	PERIODDATA	IPERATS	INTEGER	is the period number to designate for adaptive time stepping. The remaining ATS values on this line will apply to period iperats. iperats must be greater than zero. A warning is printed if iperats is greater than nper.
UTL	ATS	PERIODDATA	DT0	DOUBLE PRECISION	is the initial time step length for period iperats. If dt0 is zero, then the final step from the previous stress period will be used as the initial time step. The program will terminate with an error message if dt0 is negative.
UTL	ATS	PERIODDATA	DTMIN	DOUBLE PRECISION	is the minimum time step length for this period. This value must be greater than zero and less than dtmax. dtmin must be a small value in order to ensure that simulation times end at the end of stress periods and the end of the simulation. A small value, such as 1.e-5, is recommended.
UTL	ATS	PERIODDATA	DTMAX	DOUBLE PRECISION	is the maximum time step length for this period. This value must be greater than dtmin.
UTL	ATS	PERIODDATA	DTADJ	DOUBLE PRECISION	is the time step multiplier factor for this period. If the number of outer solver iterations are less than the product of the maximum number of outer iterations (OUTER_MAXIMUM) and ATS_OUTER_MAXIMUM_FRACTION (an optional variable in the IMS input file with a default value of 1/3), then the time step length is multipled by dtadj. If the number of outer solver iterations are greater than the product of the maximum number of outer iterations and ATS_OUTER_MAXIMUM_FRACTION, then the time step length is divided by dtadj. dtadj must be zero, one, or greater than one. If dtadj is zero or one, then it has no effect on the simulation. A value between 2.0 and 5.0 can be used as an initial estimate.
UTL	ATS	PERIODDATA	DTFAILADJ	DOUBLE PRECISION	is the divisor of the time step length when a time step fails to converge. If there is solver failure, then the time step will be tried again with a shorter time step length calculated as the previous time step length divided by dtfailadj. dtfailadj must be zero, one, or greater than one. If dtfailadj is zero or one, then time steps will not be retried with shorter lengths. In this case, the program will terminate with an error, or it will continue of the CONTINUE option is set in the simulation name file. Initial tests with this variable should be set to 5.0 or larger to determine if convergence can be achieved.
UTL	TVK	OPTIONS	PRINT_INPUT	KEYWORD	keyword to indicate that information for each change to the hydraulic conductivity in a cell will be written to the model listing file.
UTL	TVK	OPTIONS	TS6	KEYWORD	keyword to specify that record corresponds to a time-series file.
UTL	TVK	OPTIONS	FILEIN	KEYWORD	keyword to specify that an input filename is expected next.
UTL	TVK	OPTIONS	TS6_FILENAME	STRING	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.
UTL	TVK	PERIOD	IPER	INTEGER	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.
UTL	TVK	PERIOD	CELLID	INTEGER (NCELLDIM)	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.
UTL	TVK	PERIOD	TVKSETTING	KEYSTRING	line of information that is parsed into a property name keyword and values. Property name keywords that can be used to start the TVKSETTING string include: K, K22, and K33.
UTL	TVK	PERIOD	K	DOUBLE PRECISION	is the new value to be assigned as the cell's hydraulic conductivity from the start of the specified stress period, as per K in the NPF package. If the OPTIONS block includes a TS6 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.
UTL	TVK	PERIOD	K22	DOUBLE PRECISION	is the new value to be assigned as the cell's hydraulic conductivity of the second ellipsoid axis (or the ratio of K22/K if the K22OVERK NPF package option is specified) from the start of the specified stress period, as per K22 in the NPF package. For an unrotated case this is the hydraulic conductivity in the y direction. If the OPTIONS block includes a TS6 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.
UTL	TVK	PERIOD	K33	DOUBLE PRECISION	is the new value to be assigned as the cell's hydraulic conductivity of the third ellipsoid axis (or the ratio of K33/K if the K33OVERK NPF package option is specified) from the start of the specified stress period, as per K33 in the NPF package. For an unrotated case, this is the vertical hydraulic conductivity. If the OPTIONS block includes a TS6 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.
UTL	TVS	OPTIONS	DISABLE_STORAGE_CHANGE_INTEGRATION	KEYWORD	keyword that deactivates inclusion of storage derivative terms in the STO package matrix formulation. In the absence of this keyword (the default), the groundwater storage formulation will be modified to correctly adjust heads based on transient variations in stored water volumes arising from changes to SS and SY properties.
UTL	TVS	OPTIONS	PRINT_INPUT	KEYWORD	keyword to indicate that information for each change to a storage property in a cell will be written to the model listing file.
UTL	TVS	OPTIONS	TS6	KEYWORD	keyword to specify that record corresponds to a time-series file.
UTL	TVS	OPTIONS	FILEIN	KEYWORD	keyword to specify that an input filename is expected next.
UTL	TVS	OPTIONS	TS6_FILENAME	STRING	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.
UTL	TVS	PERIOD	IPER	INTEGER	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.
UTL	TVS	PERIOD	CELLID	INTEGER (NCELLDIM)	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.
UTL	TVS	PERIOD	TVSSETTING	KEYSTRING	line of information that is parsed into a property name keyword and values. Property name keywords that can be used to start the TVSSETTING string include: SS and SY.
UTL	TVS	PERIOD	SS	DOUBLE PRECISION	is the new value to be assigned as the cell's specific storage (or storage coefficient if the STORAGECOEFFICIENT STO package option is specified) from the start of the specified stress period, as per SS in the STO package. Specific storage values must be greater than or equal to 0. If the OPTIONS block includes a TS6 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.
UTL	TVS	PERIOD	SY	DOUBLE PRECISION	is the new value to be assigned as the cell's specific yield from the start of the specified stress period, as per SY in the STO package. Specific yield values must be greater than or equal to 0. If the OPTIONS block includes a TS6 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.