NASA Home Page Goddard Space Flight Center Home Page
NASA Logo - Goddard Space Flight Center   + Visit
a directory of Earth science data and services Global Change Master Directory Web site
header 2 bullet Links bullet FAQ bullet Contact Us bullet Site Map
Home Data Sets Data Services Learn about GCMD_legacy's portal collaborations. Add new dataset or dataservice records to GCMD_legacy What's New Participate Calendar About GCMD_legacy
Record Search Query: ServiceParameters>MODELS

FourPt - An Unsteady, One-Dimensional, Open-Channel Flow Model
Entry ID: USGS_FourPt

[ Get Service ]
[ Update this Record ]

Abstract: FOURPT is a numerical model for simulating unsteady, one-dimensional flow in networks of open channels. Options particularly useful in training or prototyping include selection of governing equations (kinematic, diffusion, or dynamic), boundary-value perturbation, and user-programmable constraint equations. The model can simulate non- trivial concepts, such as flow in complex interconnected channel networks, meandering channels with variable effective flow lengths, hydraulic structures defined by unique three-parameter relations, and density-driven flow. Channel geometry may be rectangular, trapezoidal, or irregular depending upon which of three channel- property modules is linked with the program.

[Summary provided by the USGS.]
Related URL
Description: Download FourPt.

The Free Software Foundation's gunzip is necessary to uncompress the UNIX tar files available below. However, some World Wide Web browsers automatically uncompress retrieved files. Thus, running gunzip as stated in the installation instructions may be unnecessary.
View entire list
Service Citation
Originators: DeLong, L.L., Thompson, D.B. and Lee, J.K.
Title: FourPt - An Unsteady, One-Dimensional, Open-Channel Flow Model
Release_Date: 1997
Provider: U.S. Geological Survey
Service Keywords

Access Constraints None
Use Constraints System Requirements:

FOURPT is written in Fortran 77 with the following extensions: use of include files, variable names longer than 6 characters, use of mixed case, and unformatted read of internal file. Memory requirements depend on array dimensioning parameters in include files. Generally, the program is easily adapted to most computer systems. The code has been used on UNIX-based computers, Macintosh, and DOS-based 386 or greater computers having a math coprocessor and 4 mb of memory.

WARNING: FOURPT is coded such that local variables are expected to be static (that is, local variables need to retain their values upon exit of a routine). Thus, the appropriate compiler option(s) must be specified to produce reliable results.
Ancillary Keywords
Flow Model
View entire list

Service Provider
DOI/USGS/WRD/OSW > Office of Surface Water, Water Resource Division, USGS, U.S. Department of the Interior Supplemental Info
Service Organization URL:

Service Provider Personnel
Email: h2osoft at
Contact Address:
Hydrologic Analysis Software Support Program
437 National Center
City: Reston
Province or State: VA
Postal Code: 20192
Country: USA
Distribution Media
Distribution_Media: Online
Fees: No fees
Email: jfulford at
Contact Address:
U.S. Geological Survey
Office of Surface Water
Building 2101, Mail Stop 1515
City: Stennis Space Center
Province or State: MS
Postal Code: 39529
Country: USA
View entire list
DeLong, L.L., 1986, Extension of the unsteady one-dimensional open- channel flow equations for flow simulation in meandering channels with flood plains, in Subitzky, S., ed., selected papers in the hydrologic sciences: U.S. Geological Survey Water-Supply Paper 2290, p. 101-105.

DeLong, L.L., 1993, A numerical model for learning concepts of streamflow simulation, in National Conference on ... View entire text
Creation and Review Dates
SERF Creation Date: 2011-12-16
SERF Last Revision Date: 2015-01-28
USA dot gov - The U.S. Government's Official Web Portal NASA
Webmaster:  Monica Lyles
Responsible NASA Official:  class="light">Stephen Berrick
Last Updated:  February 2018