GLOBAL PROCESS DATA
Name File: Contains the names of most input
and output files and controls the parts of the
model program that are active.
Discretization File: Contains data that defines
the physical size of the finite difference grid
and the fundamental components of time
discretization.
Multiplier File: Contains data to define multiplier
arrays.
Zone File: Contains data to define zone arrays.
Global Processes
1
NAME
FILE
Contains the names of most input and output files and controls the
parts of the model program that are active.
• For each simulation, in free
format
Ftype Nunit Fname
• Ftype—is the file type with
special character values. It is
not case specific.
• Nunit—is the Fortran unit to be
used when reading from or
writing to a file (1-95).
• Fname—is the name of the
file. Pathnames maybe
specified.
Global Processes
Example Name File twri.nam
Name File is read on unit 99.
Comments are indicated by
the # character in column 1.
2
FTYPE
Global for the global listing file—if this type is not present,
the LIST file is used for global listing as well as for
the forward run listing
List for the forward run listing—if this file is not present,
the Global file isused for the forward run listing as
well as for the global listing
The name file must always include a record that specifies
GLOBAL or LIST for Ftype.
Both record can be included, and if so, the GLOBAL record
must be the first non-comment record and LIST the
second non-comment record.
If only one of these records is included, it must be the first
non-comment record
Global Processes
3
FTYPE CONTINUED
Global Process Files
DIS
Discretization
MULT Multiplier Array
ZONE Zone Array
DRN
GHB
EVT
STR
CHD
GWF Process Packages
BAS6 Basic
OC
Output Control
BCF6 Block-Centered Flow
LPF
Layer Property Flow
HFB6 Horizontal Flow Barrier
RCH Recharge
RIV
River
WEL Well
Drain
General-Head Boundary
Evapotranspiration
Stream-Aquifer
Constant-Head
GWF Solvers Packages
SIP
Strongly Implicit
Procedure
SOR Slice-Successive OverRelaxation
PCG Preconditioned Conjugate
Gradient
DE4
Direct Solution
Global Processes
4
FTYPE CONTINUED
Data Files
DATA(BINARY) A binary (unformatted) file such as those used to save
cell-by-cell budget data. Rewound for parameter
estimation
DATA
A formatted (text) file such as those used to save
heads and drawdown, and for input of data from files
that are separate from primary package input files.
Rewound for parameter estimation.
Data Files For Parameter estimation (we probably won’t use these)
DATAGLO(BINARY) A binary file (unformatted)—Not rewound
DATAGLO
A formatted (text) file—Not rewound
Global Processes
5
DISCRETIZATION FILE
Contains data that defines the physical size of the finite difference grid
and the fundamental components of time discretization.
Horizontal Discretization
• Columns are numbered starting
from the left side of the grid
• Rows are numbered starting
from upper edge of grid
• Horizontal grid dimensions are
specified in variables DELR and
DELC.
• All cells in a column have the
same width so there is one value
of DELR for each of the
columns.
• There is one value of DELC for
each of the rows
Global Processes
6
DISCRETIZATION FILE CONTINUED
Vertical Discretization
• Layers are numbered from the
top layer down.
• Elevation of the top of layer 1
is defined in addition to the
bottom elevation of every
layer.
• Cell thickness is calculated
from the elevation information.
• Below each layer, except for
the bottom layer, there may be
a confining unit where only
vertical flow is treated (Quazi
3d).
• For the confining units, the
elevation of the bottom of bed
is defined.
For each layer, the present or
absents of a quazi-3D confining
bed must be indicated (LAYCBD).
Global Processes
7
DISCRETIZATION FILE CONTINUED
Time Discretization
The fundamental component of
time is the time step.
Time steps are grouped into stress
periods.
Time dependent input data can be
changed every stress period.
Specified by user each stress
period:
PERLEN
Length of stress
period
TSMULT
Time step multiplier
NSTP
Number of time
steps in a stress
period
If TSMULT>1, the length of the first
time step (Δt1) is determined from
the following equation for a
geometric series:
 TSMULT  1 
t1  PERLEN 

NSTP
1 
 TSMULT
And for 2≤m≤NSTP,
tm  TSMULT  tm1
Global Processes
8
DISCRETIZATION FILE CONTINUED
• MODFLOW can simulate steady state (SS) or
transient conditions (TR).
• A single stress period length is specified for
steady state and only a single time step is
required.
• Individual stress periods in a single simulation
maybe either steady state or transient.
• The steady state and transient stress periods
can occur in any order.
Global Processes
9
DISCRETIZATION FILE CONTINUED
• Within the listing outputs, units of length and time may
be labeled
• ITMUNI indicates the time label:
0 – undefined
3 – hours
1 – seconds
4 – days
2 - minutes
5 – years
• LENUNI indicates the length label:
0 – undefined
2 - meters
1 - feet
3 – centimeters
Note: Be sure to use consistent units for all input data!
Global Processes
10
DISCRETIZATION FILE CONTINUED
•
•
•
•
•
•
•
Spatial
NROW Number of rows
NCOL
Number of columns
NPER
Number of stress periods
ITMUNI Time unit
LENUNI Length unit
LAYCBD Quazi 3D confining layer
indicator. There is one
value for each layer.
LAYCON =1→Confining
unit
LAYCON=0→No
confining
unit
DELR
Cell width along the row,
there is one value for
each NCOL columns.
This data is read using a
utility package (U1DREL)
Discretion File Data
Discretion File Data Example
Global Processes
11
DISCRETIZATION FILE CONTINUED
•
DELC
Cell width along the
columns, there is one
value for each NROW
rows. This data is read
using a utility package
(U1DREL)
•
Top
Top elevation for
Layer 1. This data is
read using a utility
package (U2DREL)
•
BOTM
The bottom elevation.
There is one for each
layer and quazi 3D
confining layer. This
data is read using a
utility package
(U2DREL)
Discretion File Data
Discretion File Data Example
Global Processes
12
DISCRETIZATION FILE CONTINUED
•
•
•
•
Temporal
PERLEN The length of a
stress period
NSTP
Number of time
steps in a stress
period
TSMULT Multiplier for the
length of successive
time steps
Ss/Tr
Is a character
variable that
indicates if a stress
period is transient or
steady state,
Discretion File Data
Discretion File Data Example
TR Transient
SS Steady State
Note: The four temporal variables
are read for each stress
period.
Global Processes
13
PARAMETERS
• A Parameter is a single value that can be used
to determine data values for multiple cells.
• Changing the parameter value changes all of the
associated data values.
• Parameters are used in the ParameterEstimation Process because there is not enough
data to estimate all types of inputs for all cells.
• Parameters are a convenient way to specify
input data even if not using the ParameterEstimation process.
Global Processes
14
PARAMETERS
Layer or Array Data
• A value is required for every cell in one or more
horizontal of the grid (e.g. hydraulic conductivity)
• Data can either be read using the utility modules
or using parameters, but the same method must
be used consistently for any data type (e.g. if
parameters are used to define hydraulic
conductivity in a layer, then parameters must be
used to define hydraulic conductivity for all the
layers).
Global Processes
15
PARAMETERS
List Data
• Data values are required for only some of the cells (e.g.
cell that have river nodes).
• MODFLOW-2000 allows only some list data to be
defined using parameters (e.g. streambed conductance,
but not stage or river bottom elevation).
• Parameters can be used, or one line of data can be read
for each cell for which the data is required.
• It is generally possible to define some values in the list
by directly reading and other values in the same list
through parameters.
Global Processes
16
PARAMETERS
When parameters are used
for list data, the data
value for the cell is
calculated as the product
of the parameter value,
which may apply to many
cells, and a cell multiplier
or factor, which applies
only to the cell.
Global Processes
17
PARAMETERS
•
•
•
•
When parameters are used for
array data, multipliers are defined
using multiplier arrays.
There may be a different
multiplier array for each layer and
each parameter type .
If a specific parameter type has
more than one parameter values
for a layer, a zone array is used
to assign specific values to
specific cells.
There can be a different zone
array for each layer and each
parameter type.
Global Processes
18
PARAMETERS
• The data value in a cell can be determined by
more than one parameter.
• If two or more parameters of the same type
include the same cell, the final data value equals
the sum of the contributions for all of the
parameters.
• When two or more parameters are used to
define the value for cells, the parameters are
said to be additive.
Global Processes
19
PARAMETERS
Example: Use of two parameters
to determine layer data
values for the same cells.
• It is desired to have a
hydraulic conductivity
distribution (layer data) vary
linearly from 10 to 100 from
the left side to the right side.
• Let P1 and P2 be the two
parameters with multiplier
arrays shown on the right.
Global Processes
Multiplier Array for P1
Multiplier Array for P2
20
PARAMETERS
• The contributions from both
parameters will be added as
indicated in the upper right
table.
• The final result is shown in
the lower right table.
Note: The same distribution
could have been created
other ways.
Global Processes
P1=10 and P2=100
Final Result
21
PARAMETERS
Parameter P1 Data List
Example: Use of two parameters to
determine list data values for the
same cells.
• Streambed conductance is
assumed to be a mixture of two
types of material: coarse grained
(P1) and fine grained (P2)
• Parameters P1 and P2 both
include the five cells where the
two river bed materials are
intermixed.
Global Processes
Parameter P2 Data List
22
MULTIPLIER FILE
TEXT
The # character in column 1 and
any type of characters there after
up to 199 in number. Used for
comments.
NML
The number of multiplier arrays to
be defined.
MLTNAM
Name of multiplier array. May be
up to 10 characters in length and
is not case sensitive.
FUNCTION
Optional keyword indicating that a
multiplier array will be constructed
from other multiplier arrays.
Global Processes
23
MULTIPLIER FILE
[RMLT(NCOL,NROW)] – U2DREL
The multiplier array.
MLTNAM1, MLTNAM2, MLTNAM3…
Are names of the multiplier arrays
that have already been defined.
Op1, op2, op3…
Are arithmetic operators used to
define a multiplier array based other
multiplier arrays. The operators +, -,
* and / are allowed.
Global Processes
24
MULTIPLIER FILE
Example Multiplier Array Input
Using FUNCTION keyword
Global Processes
25
ZONE FILE
NZN
The number of zone arrays to be
defined.
ZONNAM
The name of a zone array May be
up to 10 characters in length and
is not case sensitive.
IZON(NCOL,NROW) – U2DINT
A zone name.
Global Processes
26
ZONE FILE
Zone File Example
Global Processes
27