Culvert Analysis Program Graphical User Interface 1.0--A preprocessing and postprocessing tool for estimating flow throu

A Preprocessing and Postprocessing Tool for Estimating Flow Through Culverts

Introduction

The peak discharge of a flood can be estimated from the elevation of high-water marks near the inlet and outlet of a culvert after the flood has occurred. This type of discharge estimate is called an “indirect measurement” because it relies on evidence left behind by the flood, such as high-water marks on trees or buildings. When combined with the cross-sectional geometry of the channel upstream from the culvert and the culvert size, shape, roughness, and orientation, the high-water marks define a water-surface profile that can be used to estimate the peak discharge by using the methods described by Bodhaine (1968). This type of measurement is in contrast to a “direct” measurement of discharge made during the flood where cross-sectional area is measured and a current meter or acoustic equipment is used to measure the water velocity. When a direct discharge measurement cannot be made at a streamgage during high flows because of logistics or safety reasons, an indirect measurement of a peak discharge is useful for defining the high-flow section of the stage-discharge relation (rating curve) at the streamgage, resulting in more accurate computation of high flows.

The Culvert Analysis Program (CAP) (Fulford, 1998) is a command-line program written in Fortran for computing peak discharges and culvert rating surfaces or curves. CAP reads input data from a formatted text file and prints results to another formatted text file. Preparing and correctly formatting the input file may be time-consuming and prone to errors. This document describes the CAP graphical user interface (GUI)—a modern, cross-platform, menu-driven application that prepares the CAP input file, executes the program, and helps the user interpret the output.

Description of the CAP GUI

The CAP GUI is organized around a series of input screens that specify the culvert type, the approach section geometry, the spatial relation between the two, and the depth of the flow. A representative sample of the input screens is shown in figure 1. The input screens are accessed from a series of menus that are arranged from left to right in the order that the data typically are entered.

The New Indirect item from the File menu opens an input screen for basic information about the flood, the survey, the system of units, and the personnel involved. This information can be edited later by selecting Project Info (fig. 1A) from the General menu. This information is not used in the computation of peak discharges or in the culvert rating.

The Shape menu defines the culvert shape. Five shapes are supported: box, circular (fig. 1B ), elliptical, pipe arch, and non-standard.

The Alignment menu specifies how the culvert is aligned in relation to the road and the flow. Three alignment options are supported: unskewed (fig. 1C ), skewed road to flow, and mitered culvert.

The culvert edging is defined using the Edging menu. Available options are no edging, rounding, beveled (fig. 1D ), bell mouth or tongue and groove, mitered end, and flared pipe.

The Wingwalls menu allows culvert wingwalls to be specified as none, equal angled (fig. 1E ), or unequal angled.

Culvert projection, either flush, equal projection (fig. 1F ), or unequal projection, is defined using the Projection menu.

The Approach menu is used to define the approach cross-section location, geometry (fig. 1G ), roughness, and water-surface elevation.

Once all the data are entered, the CAP menu controls execution of the CAP program and access to the output. The Run CAP item opens a dialog box where the user specifies the locations of the CAP input and output files. Before the CAP GUI executes CAP, it performs basic validation steps to ensure that all required data have been supplied and that all data are the correct type. It does not verify that the data are sensible.

Obtaining and Installing CAP and the CAP GUI

The CAP GUI is a Java program that interfaces with the CAP command-line Fortran program. The CAP GUI and CAP have been run successfully under Windows and Macintosh operating systems. CAP GUI, CAP, example datasets, documentation, installation requirements, and an installer are available from the CAP/CAP GUI Web page (http://water.usgs.gov/software/CAP/).

References

Bodhaine, G.L., 1968, Measurement of peak discharge 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.

Where this page came from

This page was imported from U.S. Geological Survey. Published by the U.S. Geological Survey and, as a work of the United States government, in the public domain.

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