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Online Guide to MODFLOW

Navigation: Sensitivity Process

SEN - Sensitivity Process Input File

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Abbreviation in Name file

SEN

Purpose

The Sensitivity Process is used to calculate the sensitivity of model results to variations in parameter values.

Documentation

Hill, M.C., Banta, E.R., Harbaugh, A.W., and Anderman, E.R., 2000, MODFLOW-2000, the U.S. Geological Survey modular ground-water model -- User guide to the Observation, Sensitivity, and Parameter-Estimation Processes and three post-processing programs: U.S. Geological Survey Open-File Report 00-184, 210 p.

ofr-00-184-errata.pdf

Related Packages

The PVAL input file in MODFLOW-2005 and MODFLOW-LGR provides a little of the functionality of the Sensitivity process in MODFLOW-2000.

Supported in

MODFLOW-2000

Other Notes

The "Model-Layer Variable-Direction Horizontal Anisotropy" capability is incompatible with the Sensitivity process when convertible layers are used.

Parameters in the Streamflow Routing (SFR) package can not be specified in the Sensitivity process input file.

The Sensitivity Process is not included in MODFLOW-2005 or MODFLOW-LGR.  External programs such as UCODE must be used instead.

Sensitivity Process

Input Instructions

Input for the Sensitivity Process is read from a file that is specified with “SEN” as the file type listed in the name file.

Data Set 0

[#Text]

Item 0 is optional and can include as many lines as desired. Each line needs to begin with the “#” character in the first column.

Data Set 1

NPLIST ISENALL IUHEAD MXSEN (free format)

Data Set 2

IPRINTS ISENSU ISENPU ISENFM (free format)

Data Set 3

PARNAM ISENS LN B BL BU BSCAL (free format)

Read NPLIST repetitions of item 3.

Example Input File

# Example SEN file

#

11 0 -36 11 ITEM 1: NPLIST ISENALL IUHEAD MXSEN

0 0 0 0 ITEM 2: IPRINTS ISENSU ISENPU ISENFM

WQ_1 1 0 45. 40. 50. 10. ITEMS 3: PARNAM ISENS LN B BL BU BSCAL

WQ_2 1 0 420. 320. 520. 100.

WQ_3 1 0 -9.7E4 –1.1E5 -9.0E4 9.0E4

WQ_4 1 0 -5.1E4 -6.1E4 -4.1E4 4.1E4

RCH_ZONE_1 1 0 0.4E-3 0.4E-4 0.4E-2 0.4E-2

RCH_ZONE_2 1 0 -0.2E-3 -0.2E-2 -0.2E-4 0.2E-4

RCH_ZONE_3 1 0 0.17E-3 0.17E-4 0.17E-2 0.17E-4

rivers 1 1 0.8E-1 0.7E-1 0.9E-1 0.7E-1

HK_1 1 1 70. 40. 100. 0.1

HK_2 1 1 420. 320. 520. 1.0

HK_3 1 1 15. 10. 20. 0.01

 

In this example, WQ_1, WQ_2, WQ_3, WQ_4, RCH_ZONE_1, RCH_ZONE_2, RCH_ZONE_3, rivers, HK_1, HK_2, and HK_3 are the names of parameters defined in Groundwater Flow Process input files. The Sensitivity Process matches parameter names with those defined in the Groundwater Flow Process input files in a case-insensitive manner.

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