PVAL - Parameter Value File

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Abbreviation in Name file

PVAL

Purpose

Parameter values in this file replace parameter values specified in the files where parameters are defined.

Documentation

•Harbaugh, A.W., 2005, MODFLOW-2005, the U.S. Geological Survey modular ground-water model -- the Ground-Water Flow Process: U.S. Geological Survey Techniques and Methods 6-A16, variously p.

•Hanson, R.T., Boyce, S.E., Schmid, Wolfgang, Hughes, J.D., Mehl, S.M., Leake, S.A., Maddock, Thomas, III, and Niswonger, R.G., 2014, One-Water Hydrologic Flow Model (MODFLOW-OWHM): U.S. Geological Survey Techniques and Methods 6–A51, 120 p., http://dx.doi.org/10.3133/tm6A51.

Related Packages

The Sensitivity (SEN ) process in MODFLOW-2000 provides the same functionality as the PVAL input file and more.

Supported in

•MODFLOW-2005

•MODFLOW-LGR

•MODFLOW-CFP

•MODFLOW-NWT

•MODFLOW-OWHM

The Parameter Value File is the file that is specified with “PVAL” as the file type. Parameter values in this file replace parameter values specified in the files where parameters are defined.

FOR EACH SIMULATION

Data Set 0

[#Text]

Item 0 is optional—“#” must be in column 1. Item 0 can be repeated multiple times.

Text—is a character variable (199 characters) that starts in column 2. Any characters can be included in Text. The “#” character must be in column 1. Lines beginning with # are restricted to the first lines of the file. Text is written to the Listing File.

Data Set 1

NP {OPTIONS}

NP repetitions of Item 2 are read.

The keyword PROPPRINT will cause property arrays defined using parameters in the LPF or UPW packages to be printed to separate files. This option is only available in MODFLOW-OWHM. However, this information can be printed to the listing file in any version of MODFLOW.

For parameter estimation and visualization purposes, the user can now output the actual property arrays that are constructed and used by LPF or UPW. This aids in understanding the final result for input files that contain complex parameter scaling, multiplier arrays, and zone arrays. The arrays are printed as row-column slices to a separate file for each LGR grid and layer. Some of the properties that are printed include lateral hydraulic conductivities (Kx, Ky), vertical hydraulic conductivities (Kv), specific storage (Ss), and specific yield (Sy).

To initiate printing of the model parameters to separate files the keyword “PROPPRINT” is specified in the PVAL file after the variable NPVAL. If PVAL is not needed, but parameter printing is desired, then PVAL must appear in the NAM file and NPVAL be set to 0, followed by the keyword “PROPPRINT” (without quotes).

PROPPRINT is read as part of the PVAL file, which structure would be as follows:

#URWORD COMMENTS THAT BEGIN WITH “#”

NPVAL {OPTIONS}

Where

OPTIONS is the optional keyword “PROPPRINT” without quotes

When activated, this option will output for each model layer individual files for each hydraulic property used within the model (only model layer 1-L1 shown here), such as the following:

Horizontal hydraulic conductivity: PARAM_HKC_G1_L1.txt

Conductivity Anisotropy Ratio: PARAM_HKR_G1_L1.txt

Vertical Hydraulic Conductivity: PARAM_VKA_G1_L1.txt

Specific Storage: PARAM_Ss_G1_L1.txt

Specific Yield: PARAM_Sy_G1_L1.txt”

 

Data Set 2

PARNAM Parval

NP repetitions of Item 2 are read.

PARNAM—is the name of a parameter whose value is to be defined. This name can consist of 1 to 10 characters and is not case sensitive. That is, any combination of the same characters with different case will be equivalent.

Parval—is the parameter value. This value overrides the parameter value specified in the file where the parameter is defined.