NAME
Cap - Culvert Analysis Program
ABSTRACT
CAP follows USGS standardized procedures for computing flow through
culverts. It can be used to develop stage-discharge relationships
for culverts and to determine discharge through culverts from high
water marks. It will compute flows for rectangular, circular, pipe
arch, elliptical, and other nonstandard shaped culverts.
METHOD
The program solves the 1-D steady-state energy and continuity
equations for upstream water-surface elevation given a discharge and
a downstream water-surface elevation.
HISTORY
Version 97-08c 1999/11/15 - Defined variable that was defaulting to
unintended data type and causing divide-by-zero error.
Version 97-08b 1999/09/03 - Code fixed to ensure 0 returned for one
function when flow equation root doesn't close to specified
criteria. Minor corrections made in display of warning messages.
Version 97-08a 1998/12/07 - Elliptical culvert sections added.
Version 97-08 1997/08/30 - Version as documented in USGS Water-
Resources Investigations Report 98-4166.
Version 97-01 1997/05/01 - Several additions have been made to the
CAP program to reduce the effort required to assemble input data.
The major new features are: (1) metric conversion options (a new
record implements this feature); (2) default values for C5 and
C46 coefficients; (3) new input record for geometry data for
inlet details.
The following describes problems in the code that have been
corrected. The *CF record variable, HFLW, did not affect
computations as was stated in Open-File Report 95-137.
Meaningless fall and loss values for computations made by
linearly interpolating between high head and low head flows were
included in results. For nonstandard culvert descriptions using
the *CS record, if the left-most coordinate pair was not entered
first on the *CS record, an erroneous width was printed in the
results. Skew angles entered on the XS record that describes the
approach section geometry did not affect the computations. The
CG record variable, ICODE, did not affect pipe arch computations
appropriately. The report also neglected to state that the J
portion of the ICODE is required for pipe arches. The J portion
of the ICODE should be entered for pipe arches and indicates the
material used and, for corrugated pipe, the corner radius of the
pipe when BOTRAD, TOPRAD, and CORRAD are not specified. Omission
of a valid J value will result in the program failing to work.
The J codes are as follows:
1- concrete pipe, 2,4- corrugated metal pipe, corner radius<= 18"
3- aluminum pipe, 5- corrugated metal pipe, corner radius = 31"
6- corrugated metal pipe, corner radius = 47"
These codes may not be compatible with WSPRO J codes for some
cases.
Version 94-10 1995/10/31 - Version as documented in USGS Open-File
Report 95-137.
1993 - The CAP program was developed using an antecedent program,
A526, as a guide for some of the routines. Several features that
were not available in A526 were included. These features are
computations for nonstandard culvert sections, default
computation of discharge coefficients for flow types 1, 2, and 3,
computation between flow transitions, and input file formats that
are compatible with WSPRO input formats.
DATA REQUIREMENTS
Measurements of culvert geometry, culvert roughness, and culvert
inlet, and measurements of approach section geometry and roughness.
OUTPUT OPTIONS
Two outputs are available--a condensed table of computed values that
is meant for use by other computer programs and a text form that
summarizes the computations made by the program.
SYSTEM REQUIREMENTS
The program is written in Fortran 77 with the following extensions:
include files, variable names longer than 6 characters, and common
block with character and noncharacter variables. Generally, the
program is easily installed on most computer systems. The code has
been used on UNIX-based computers and DOS-based 386 or greater
computers having a math coprocessor.
DOCUMENTATION
Bodhaine, G.L., 1968, Measurement of peak discharges at culverts by
indirect methods: U.S. Geological Survey Techniques of Water-
Resources Investigations, book 3, chap. A3, 60 p.
Fulford, J.M., 1998, User's guide to the U.S. Geological Survey
Culvert Analysis Program, Version 97-08: U.S. Geological Survey
Water-Resources Investigations Report 98-4166, 70 p.
TRAINING
Surface-Water Hydraulic Analysis (G0093), offered annually at the
USGS National Training Center.
CONTACTS
Operation and 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 CAP software
can be retrieved are, respectively:
http://water.usgs.gov/software/Cap.html
--and--
/pub/software/surface_water/Cap
If you would like to obtain the price of and (or) order paper copies
of USGS reports, contact the USGS Branch of Information Services at:
USGS Information Services
Box 25286
Denver Federal Center
Denver CO 80225
To inquire about Open-File Reports or Water-Resources Investigations
Reports:
Tel: 303-202-4200; Fax 303-202-4695
To inquire about other USGS reports:
Tel: 303-202-4700; Fax 303-202-4693
SEE ALSO
wspro88(1) - A computer model for Water-Surface PROfile
computations