NAME
modbrnch - MODFLOW/BRANCH coupled flow model
ABSTRACT
Surface- and ground-water interactions can be simulated by the
coupled BRANCH and USGS modular, three-dimensional, finite-
difference ground-water flow (MODFLOW-96) models, referred to as
MODBRNCH. MODFLOW-96 simulates steady and nonsteady flow in an
irregularly shaped flow system in which aquifer layers can be
confined, unconfined, or a combination of confined and unconfined.
BRANCH simulates steady or unsteady flow in a single open-channel
reach (branch) or throughout a system of branches (network)
connected in a dendritic or looped pattern by solving the one-
dimensional equations of continuity and momentum for the river flow.
Channel-aquifer flows are leakage through a confining layer or
riverbed. Computation of this leakage in the ground-water and
surface-water systems allows these processes to be coupled for
simulation purposes.
METHOD
The ground-water flow equation is solved using the finite-difference
approximation. The BRANCH model uses a weighted four-point,
implicit, finite-difference approximation of the unsteady-flow
equations. A leakage term has been added to the equations in the
BRANCH model and was coupled through the leakage quantity to the
MODFLOW-96 model.
HISTORY
Version 3.7 1997/06/05 - Use name file to designate input and output
file names. Updated to be compatible with MODFLOW-96 version 3.1
and BRANCH version 4.3.
Version 3.6 1995/11/09 - First version available on World Wide Web.
Coupled with MODFLOW version 2.5 and BRANCH version 4.0.
DATA REQUIREMENTS
In order to use MODFLOW, initial conditions, hydraulic properties,
and stresses must be specified for every model cell in the finite-
difference grid. BRANCH input data consist of channel geometry and
initial flow conditions defined at all cross-section locations and
boundary conditions defined at channel extremities. Refer to input
specifications instructions for the MODFLOW-96 and BRANCH models for
specific details.
OUTPUT OPTIONS
Primary ground-water computational output is head, which can be
written to the listing file or into a separate file. Other output
includes the complete listing of all input data, drawdown, and
budget data. Budget data are printed as a summary in the listing
file, and detailed budget data for all model cells can be written
into a separate file.
Time series of computed surface-water flow results can be directly
output in tabular or graphical form at all, or selected, cross-
section locations. Tabular output options include discrete flow
results at every time step or iteration; daily summaries of minimum,
maximum, and average flow conditions; monthly flow-volume summaries;
or river-mile locations of injected particles. Digital or line-
printer graphical options include hydrograph plots of computed water
levels or discharges or comparative plots of computed results versus
measured data. Output results can be either in metric or inch-pound
units.
SYSTEM REQUIREMENTS
MODBRANCH is written in Fortran 77 with the following extensions:
use of integer*2 declarations, use of include files, variable names
longer than 6 characters, use of mixed case, and reference to
compiler-dependent system date and time routines. To compile
MODBRANCH the BRANCH and MODFLOW-96 software and LIBUTL utility
library are required. LIBUTL includes software/user,
software/computer, software/data base, and software/graphics
interaction routines. MODBRANCH graphics (from the BRANCH model)
are coded using CalComp graphics calls. The LIBUTL software
provides graphics libraries to convert CalComp graphic references to
Graphical Kernel System (GKS) library references and Interactive
Software Services's INTERACTER library references. MODBRANCH memory
requirements depend on array dimensioning parameters found in the
dimens.cmn include file and modflw96.f source file. The memory
requirements can be tailored to suit application needs and computer
system memory constraints by modifying the parameters in these files
and then recompiling the code. Generally, the program is easily
adapted to most computer systems that have access to one of the
mentioned graphics libraries. The code has been used on UNIX-based
computers and DOS-based 386 or greater computers having a math
coprocessor and 8 mb of memory.
DOCUMENTATION
Swain, E.D., and Wexler, E.J., 1996, A coupled surface-water and
ground-water flow model (MODBRNCH) for simulation of stream-
aquifer interaction: U.S. Geological Survey Techniques of Water-
Resources Investigations, book 6, chap. A6, 125 p.
Swain, E.D., 1992, Incorporating hydraulic structures in an open-
channel model: Proceedings, 1992 National Hydraulic Engineering
Conference, American Society of Civil Engineers, New York, N.Y.,
p. 1118-1123.
RELATED DOCUMENTATION
BRANCH
Schaffranek, R.W., 1987, Flow model for open-channel reach or
network: U.S. Geological Survey Professional Paper 1384, 12 p.
Schaffranek, R.W., Baltzer, R.A., and Goldberg, D.E., 1981, A model
for simulation of flow in singular and interconnected channels:
U.S. Geological Survey Techniques of Water-Resources
Investigations, book 7, chap. C3, 110 p.
Latest version enhancements and additions to the BRANCH model are
documented and maintained in a file included in the software
distribution. The latest model version is downward compatible with
the original documentation:
MODFLOW
The basic model is documented in:
Harbaugh, A.W., and McDonald, M.G., 1996, User's documentation for
MODFLOW-96, an update to the U.S. Geological Survey modular
finite-difference ground-water flow model: U.S. Geological Survey
Open-File Report 96-485, 56 p.
Harbaugh, A.W., and McDonald, M.G., 1996, Programmer's documentation
for MODFLOW-96, an update to the U.S. Geological Survey modular
finite-difference ground-water flow model: U.S. Geological Survey
Open-File Report 96-486, 220 p.
McDonald, M.G., and Harbaugh, A.W., 1988, A modular three-
dimensional finite-difference ground-water flow model: U.S.
Geological Survey Techniques of Water-Resources Investigations,
book 6, chap. A1, 586 p.
GENERAL
Harbaugh, A.W., 1990, A simple contouring program for gridded data:
U.S. Geological Survey Open-File Report 90-144, 37 p.
Regan, R.S., and Schaffranek, R.W., 1985, A computer program for
analyzing channel geometry: U.S. Geological Survey Water-
Resources Investigations Report 85-4335, 49 p.
Regan, R.S., Schaffranek, R.W., and Baltzer, R.A., 1996, Time-
Dependent Data System (TDDS)--An interactive program to assemble,
manage, and appraise input data and numerical output of
flow/transport simulation models: U.S. Geological Survey Water-
Resources Investigations Report 96-4143, 104 p.
Sanders, C.L., 1995, The use of three-parameter rating table lookup
programs, RDRAT and PARM3, in hydraulic flow models: U.S.
Geological Survey Water-Resources Investigations Report 95-4090,
18 p.
TRAINING
Modeling of Ground-Water Flow Using Finite-Difference Methods
(GW2096TC), offered annually at the USGS National Training Center.
Advanced Modeling of Ground-Water Flow (GW3099TC), offered annually
at the USGS National Training Center.
Ground-Water/Surface-Water Relationships (ID2015TC), offered
annually at the USGS National Training Center.
Implementation and Calibration of Unsteady Open-Channel Flow
Transport Models (SW3091TC), offered annually at the USGS National
Training Center.
CONTACTS
Operation:
U.S. Geological Survey
Eric Swain
9100 NW 36 Street, Suite 107
Miami, FL 33178
edswain@usgs.gov
Distribution:
U.S. Geological Survey
Hydrologic Analysis Software Support Program
437 National Center
Reston, VA 20192
h2osoft@usgs.gov
Official versions of U.S. Geological Survey water-resources analysis
software are available for electronic retrieval via the World Wide
Web (WWW) at:
http://water.usgs.gov/software/
and via anonymous File Transfer Protocol (FTP) from:
water.usgs.gov (path: /pub/software).
The WWW page and anonymous FTP directory from which the MODBRNCH
software can be retrieved are, respectively:
http://water.usgs.gov/software/modbrnch.html
--and--
/pub/software/surface_water/modbrnch
SEE ALSO
branch(1) - One-dimensional Branch-network flow model
cgap(1) - Channel Geometry Analysis Program
contour(1) - A contouring program for gridded data
libutl(1) - Utility libraries for simulation models
modflow(1) - Modular three-dimensional ground-water flow
model
Modflowp(1) - Parameter-estimation version of the modular model
modpath(1) - Particle-tracking postprocessor program for
the modular three-dimensional finite-difference
ground-water flow model
tdds(1) - Time-Dependent Data System
wdm(1) - Watershed Data Management system