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Open-File Report 03—473

Computation of Flow Through Water-Control Structures Using Program DAMFLO.2

U.S. Geological Survey Open-File Report 03—473, 109 pages (Published March 2004)

Curtis L. Sanders, Jr. and Toby D. Feaster

This report is available online in pdf format (3 MB): USGS OFR 03-473.pdf


Cover of OFR 03-473.

As part of its mission to collect, analyze, and store streamflow data, the U.S. Geological Survey computes flow through several dam structures throughout the country. Flows are computed using hydraulic equations that describe flow through sluice and Tainter gates, crest gates, lock gates, spillways, locks, pumps, and siphons, which are calibrated using flow measurements. The program DAMFLO.2 was written to compute, tabulate, and plot flow through dam structures using data that describe the physical properties of dams and various hydraulic parameters and ratings that use time-varying data, such as lake elevations or gate openings. The program uses electronic computer files of time-varying data, such as lake elevation or gate openings, retrieved from the U.S. Geological Survey Automated Data Processing System. Computed time-varying flow data from DAMFLO.2 are output in flat files, which can be entered into the Automated Data Processing System database. All computations are made in units of feet and seconds. DAMFLO.2 uses the procedures and language developed by the SAS Institute Inc.


The installation shell script is available for downloading over the Internet from the public anonymous File Transfer Protocol (FTP) server (internet address in the directory pub/damflo. When the system administrator executes the installation script file with root access from any directory on the SUN Microsystems (Solaris 8) computer, it will transfer, install, and create the necessary programs, directories, and links. The DAMFLO.2 programs are stored in the directory /usr/opt/wrdapp/locapp/damflo by the script program. DAMFLO.2 utilizes the SAS software package marketed by the SAS institute, Inc. (1993). Therefore, one copy of the SAS software also needs to be installed on the SUN computer.


Several steps are required prior to executing the DAMFLO.2 program. A working directory should be created for the station where the dam computations are being made. In the station directory, all time-varying data required for computations at the dam of interest must be retrieved and stored sequentially in a single file. The static input data defining the hydraulic parameters for the outlets must be entered into the SAS database by typing damflo and using the appropriate options (4-14) from the damflo menu. Using a text editor, a run.primary file with the specific calls needed for the flow computations at the dam of interest must be created and stored in the working directory. After completing these tasks, the program is executed by typing damflo and choosing option 1, 2, or 3 from the screen menu below.


1. Plot and table to the terminal screen.
2. Plot and table to the printer.
3. Only print uv and dv primary files and produce uv and dv card image files.


4. Control 10. Locks
5. Interpolation 11. Lockgates
6. Ratings 12. Crest gates
7. Stage 13. Pumps
8. Tainter gates 14. Siphons
9. Spillways


15. Plot hydraulic ratings
Select one of options 1-15:

Figure 2. Example of the damflo menu.




Purpose and Scope

General Description of Program DAMFLO.2

Time-Varying Input Data

Static Input Data

Static Stage Data Limits

Static Hydraulic Rating Data

Static Physical and Hydraulic Parameter Data

Program Operation

Program Output

Hydraulic Methodology

Gate Flow

Orifice Flow

Leakage for Free- and Submerged-Weir Flow Conditions

Weir Flow

Differentiation Between Free- and Submerged-Weir Flow Conditions

Differentiation Between Submerged-Orifice and Submerged-Weir Flow Conditions

Fixed-Spillway Flow

Lock Flow

Lock-Gate Flow

Crest-Gate Flow

Pump Flow

Siphon Flow

Program Installation

Data Entry and Program Operation

Unit-Values Time Series Data

Static Data Programs

Control (option 4).

Interpolation (option 5)

Ratings (option 6)

Stage (option 7)

Tainter gates (option 8)

Spillway (option 9)

Locks (option 10)

Lockgates (option 11)

Crest gates (option 12)

Pumps (option 13)

Siphons (option 14)

Plot hydraulic ratings (option 15)

Program Execution and Output















Utility Programs








Appendix 1 - Velocity-Fall Method for Computing Submerged-Weir Flow

Appendix 2 - Computation of Vertical Openings at Tainter Gates

Appendix 3 - Classification of Free- and Submerged-Orifice Flow by Proposed Hydraulic Jump Method

Appendix 4 - Unit-Value and Daily-Value Card Formats


This report is available online in pdf format (3 MB): USGS OFR 03-473
To view the PDF document, you need the Adobe Acrobat® Reader installed on your computer. (A free copy of the Acrobat® Reader may be downloaded from Adobe Systems Incorporated.)

For more information, contact the South Carolina Publications Unit.

USGS South Carolina Publications South Carolina Water Science Center

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