Cap(1) U.S. Geological Survey (wrdapp) Cap(1) 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: 16 December 1999 1 Cap(1) U.S. Geological Survey (wrdapp) Cap(1) 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 16 December 1999 2 Cap(1) U.S. Geological Survey (wrdapp) Cap(1) 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 16 December 1999 3