ETS - Evapotranspiration Segments Package

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Abbreviation in Name file

ETS

Purpose

The Evapotranspiration Segments Package allows simulation of evapotranspiration with a user-defined relation between evapotranspiration rate and hydraulic head.

Documentation

Banta, E.R., 2000, MODFLOW-2000, the U.S. Geological Survey Modular Ground-Water Model - Documentation of Packages for Simulating Evapotranspiration with a Segmented Function (ETS1) and Drains with Return Flow (DRT1): U.S. Geological Survey Open-File Report 00-466, 127 p.

Time-varying-parameters.pdf

release.txt for MODFLOW-2005

Related Packages

Evapotranspiration

Riparian Evapotranspiration

Head-Dependent Flux Boundary packages

Supported in

MODFLOW-2000

MODFLOW-2005

MODFLOW-LGR

MODFLOW-CFP

MODFLOW-NWT

MODFLOW-OWHM

Common Errors

Evapotranspiration is applied to the wrong cells because NETSOP was not set correctly.

Other Notes

The UZF package simulates evapotranspiration so the ETS package is not normally included in a model that includes the UZF package or at least not in the same locations.

The evapotranspiration simulated by the ETS package only includes evapotranspiration from the saturated zone. Recharge is sometime calculated as precipitation minus losses between the land surface and the water table. Evapotranspiration from the unsaturated zone would be one such loss. Another such loss would be surface runoff.

Input Instructions

Input to the ETS1 Package is read from the file that is type “ETS” in the name file. All single-valued variables are free format if the option “FREE” is specified in the Basic Package input file; otherwise, the variables have 10-character fields. Arrays are read by an array-reading utility module, either U2DREL or U2DINT (Harbaugh and others, 2000), as indicated. Optional variables are shown in brackets.

FOR EACH SIMULATION

Data Set 0

[#Text]

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

Data Set 1

NETSOP IETSCB NPETS NETSEG

Repeat Items 2 and 3 for each parameter to be defined (that is, NPETS times). Items 2 and 3 are omitted if NPETS = 0.

Data Set 2

[PARNAM PARTYP Parval NCLU [INSTANCES NUMINST]]

If PARNAM is to be a time-varying parameter, the keyword INSTANCES and a value for NUMINST must be entered.

Data Set 3a

INSTNAM

Item 3a is read only if PARNAM is time-varying. NUMINST repetitions of Item 3 (parts a and b) are read. After each repetition of Item 3a, NCLU repetitions of Item 3b are read.

Data Set 3b

[Mltarr Zonarr IZ]

Each repetition of Item 3b record is called a parameter cluster. Repeat Item 3b NCLU times. The NCLUrepetitions of Item 3b follow each repetition of Item 3a when PARNAM is time-varying.

FOR EACH STRESS PERIOD

Data Set 4

INETSS INETSR INETSX [INIETS [INSGDF]]

Data Set 5

[ETSS(NCOL,NROW)] – U2DREL – If INETSS ≥0

Either Item 6 or Item 7 may be read, but not both. If Item 7 is read, it is repeated INETSR times.

Data Set 6

[ETSR(NCOL,NROW)] – U2DREL – If NPETS = 0 and if INETSR ≥0

Data Set 7

[Pname [Iname] [IETSPF]] – If NPETS > 0 and if INETSR > 0

Iname is read if Pname is a time-varying parameter. If IETSPF is specified for a non-time-varying parameter, Iname must be omitted.

Data Set 8

[ETSX(NCOL,NROW)] – U2DREL – If INETSX ≥0

Data Set 9

[IETS(NCOL,NROW)] – U2DINT – If NETSOP = 2 and if INIETS ≥0

If NETSEG > 1, (NETSEG −1) repetitions of items 10 and 11 are read. If NETSEG > 2, items 10 and 11 are read for the uppermost segment intersection, followed by repetitions of items 10 and 11 for successively lower intersections.

Data Set 10

[PXDP(NCOL,NROW)] – U2DREL – If NETSEG > 1 and INSGDF ≥0

Data Set 11

[PETM(NCOL,NROW)] – U2DREL – If NETSEG > 1 and INSGDF ≥0