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Navigation: Online Guide to MODFLOW > Groundwater Flow Process > Groundwater Flow Packages > HUF2 - Hydrogeologic-Unit Flow Package

LVDA - Model-Layer Variable-Direction Horizontal Anisotropy Capability

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Abbreviation in Name file

LVDA

Purpose

The LVDA capability allows the principal directions of horizontal anisotropy to be different than the model-grid row and column directions, and for the directions to vary on a cell-by-cell basis within model layers.

Documentation

Anderman, E.R., Kipp, K.L., Hill, M.C., Valstar, Johan, and Neupauer, R.M., 2002, MODFLOW-2000, the U.S. Geological Survey modular ground-water model -- Documentation of the Model-Layer Variable-Direction Horizontal Anisotropy (LVDA) capability of the Hydrogeologic-Unit Flow (HUF) Package: U.S. Geological Survey Open-File Report 02-409, 60 p.

Supported in

MODFLOW-2000

MODFLOW-2005

MODFLOW-LGR

MODFLOW-NWT

MODFLOW-OWHM

Other Notes

The "Model-Layer Variable-Direction Horizontal Anisotropy" capability is provided in the LVDA input file but is part of the Hydrogeologic-Unit Flow package (HUF2).

The "Model-Layer Variable-Direction Horizontal Anisotropy" capability is incompatible with the Horizontal Flow Barrier (HFB) package.

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

Input Instructions

The LVDA capability is a modification to the existing Hydrogeologic-Unit Flow (HUF) Package (Anderman and Hill, 2000). This section describes the new input file needed with the LVDA capability and the changes in the HUF Package output files resulting from using the LVDA capability. There are no changes in the HUF Package output files if the LVDA capability is not used. Although the HUF input file is not changed when using the LVDA capability, the definition of two parameter types does change. The new definitions are presented below.

Printing of the LVDA model layer arrays is not supported by the print capability represented by item 12 of the HUF Package input file. Printing these arrays requires use of the new printing capability for the HUF Package documented by Anderman and Hill (in review).

Input for the Model-Layer Variable-Direction Horizontal Anisotropy capability is read from the file that has type “LVDA” in the Name file. Free format is used for reading all values. This file defines the horizontal anisotropy direction for each cell of the finite-difference grid.

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

Repeat Items 2 and 3 for each parameter to be defined (that is, NPLVDA times).

Data Set 2

PARNAM PARTYP Parval NCLU

Data Set 3

Layer Mltarr Zonarr IZ

Each Item 3 record is called a parameter cluster. Repeat Item 3 NCLU times.