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Online Guide to MODFLOW-NWT

Abbreviation in Name file

STR

Purpose

The Stream package is used to simulate streams in a model.  The flow in a stream is routed instantaneously to downstream streams

Documentation

Prudic, D.E., 1989, Documentation of a computer program to simulate stream-aquifer relations using a modular, finite-difference, ground-water flow model: U.S. Geological Survey Open-File Report 88-729, 113 p.

str6.pdf

STR7.pdf

Related Packages

Stream Observation package

Streamflow-Routing (SFR) package

Surface-Water Routing (SWR) process

Supported in

MODFLOW-2000

MODFLOW-2005

MODFLOW-LGR

MODFLOW-CFP

MODFLOW-NWT

MODFLOW-OWHM

Common Errors

Stream reaches within segments are listed from downstream to upstream instead of from upstream to downstream.

Linkages between streams are not specified.

Linkages between streams are specified incorrectly.

Other Notes

Compared with the Stream (STR) package, the Streamflow-Routing (SFR) provides greater flexibility in how streams are specified but the parameters in it can not be used with the Sensitivity or Parameter-Estimation processes.

Prior to MODFLOW-2005 version 1.11, the Stream package did not support the "FREE" option of the Basic Package, so input was required to be entered in fixed-field format where indicated.

In MODFLOW-2005 version 1.11 and later, variables are free format if the option “FREE” is specified in the Basic Package input file; otherwise, most variables are read with the indicated fixed format.

MODFLOW-LGR and MODFLOW-CFP always uses the fixed-field format as in MODFLOW-2005 prior to version 1.11.

The Stream (STR) package was originally called the "Streamflow-Routing" package.  This name is identical with the name of the SFR package.  The name  "Stream" rather than "Streamflow-Routing" is adopted here for the STR package to minimize confusion.

Input Instructions

Input to the modified version of the Stream (STR) Package is read from the file that has file type "STR" in the MODFLOW name file. Optional variables are shown in brackets. All variables are read with fixed format except as noted.

FOR EACH SIMULATION

Data Set 0

[#Text]

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

Data Set 1

[PARAMETER NPSTR MXL]

This optional record is read with free format; it must start with the word “PARAMETER”.

Data Set 2

MXACTS NSS NTRIB NDIV  ICALC CONST ISTCB1 ISTCB2 Option

I10 I10 I10 I10 I10 F10.0 I10 I10 Free

In MODFLOW-2005 version 1.11 and later, variables are free format if the option “FREE” is specified in the Basic Package input file.

Repeat Items 3 and 4 for each of NPSTR parameters.

Data Set 3

[PARNAM PARTYP Parval NLST [INSTANCES NUMINST]]

Item 3 is read with free format. If PARNAM is to be a time-varying parameter, the keyword “INSTANCES” and a value for NUMINST must be entered.

Data Set 4a

[INSTNAM]

Item 4a is read only if PARNAM is time varying. NUMINST repetitions of Item 4 (parts a and b) are read. After each repetition of Item 4a, NLST repetitions of Item 4b are read.

Data Set 4b

[Layer Row Col Seg Reach Flow Stage Condfact Sbot Stop] [xyz]

I5 I5 I5 I5 I5 F15.0 F10.0 F10.0 F10.0 F10.0 Free

In MODFLOW-2005 version 1.11 and later, variables are free format if the option “FREE” is specified in the Basic Package input file.

NLST repetitions of Item 4b are required. The NLST repetitions of Item 4b follow each repetition of Item 4a when PARNAM is time varying.

FOR EACH STRESS PERIOD

Data Set 5

ITMP IRDFLG IPTFLG

I10 I10 I10

In MODFLOW-2005 version 1.11 and later, variables are free format if the option “FREE” is specified in the Basic Package input file.

[Note that either Item 6 or Item 7 may be read, but not both.]

Data Set 6

Layer Row Col Seg Reach Flow Stage Cond Sbot Stop [xyz]

I5 I5 I5 I5 I5 F15.0 F10.0 F10.0 F10.0 F10.0 Free

In MODFLOW-2005 version 1.11 and later, variables are free format if the option “FREE” is specified in the Basic Package input file.

Item 6 is repeated ITMP times if NPSTR=0. If ITMP<0, Item 6 records are used from the previous stress period.

Data Set 7

[Pname [Iname]]

Item 7 is repeated ITMP times if NPSTR>0. Free format is used. Iname is read if Pname is a time-varying parameter.

Data Set 8

Width Slope Rough

F10.0 F10.0 F10.0

In MODFLOW-2005 version 1.11 and later, variables are free format if the option “FREE” is specified in the Basic Package input file.

Item 8 is read only if ICALC > 0, in which case Item 8 is repeated for every stream reach. The records must be is the same order as the stream reaches.

Data Set 9

Itrib(NTRIB)

10I5

In MODFLOW-2005 version 1.11 and later, variables are free format if the option “FREE” is specified in the Basic Package input file.

Item 9 is read only if NTRIB > 0, in which case Item 9 is repeated NSS times in sequential order of the segments. Each record contains NTRIB values.

Data Set 10

Iupseg

I10

In MODFLOW-2005 version 1.11 and later, variables are free format if the option “FREE” is specified in the Basic Package input file.

Item 10 is read only if NDIV>0, in which case Item 10 is repeated NSS times in sequential order of the segments.

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