U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590

Skip to content U.S. Department of Transportation/Federal Highway AdministrationU.S. Department of Transportation/Federal Highway Administration

Bridges & Structures


FHWA Hydraulic Toolbox

The FHWA Hydraulic Toolbox Program is a stand-alone suite of calculators that performs routine hydrologic and hydraulic analysis and design computations. Specific calculators address: Rational Method hydrology, channels, channel linings, weirs, curb and gutter sections, storm drain inlets, detention basins, bridge scour, riprap countermeasures, sediment gradations, and culvert assessments. The Hydraulic Toolbox significantly extends the basic functionality of the historic version of the FHWA Visual Urban Program and other tools. The program allows a user to perform and save hydraulic calculations in one project file, analyze multiple scenarios, and create plots and reports of these analyses. The computations can be carried out in either US Customary Units or the International System of Units.

A FHWA Hydraulic Toolbox Desktop Reference Guide is included with the software installation (access via ‘Help’ button on top toolbar) to provide important information on the technical features, capabilities, and limitations of the calculators.

System Compatibility

The Hydraulic Toolbox (Toolbox) is a 64-bit program and only compatible with 64-bit Windows-based operating systems. When installing the Toolbox, make sure you have permissions on your computer to install programs (usually this requires administrator permissions or a username and password for an administrator account). If you do not have administrator permissions on your account, you need to right-click on the installation program and select the "Run as Administrator" option.

Download Agreement

By downloading the software, users agree to the following terms and conditions:

  • FHWA does not provide user assistance or support for this software.
  • The application of this software is the responsibility of the user. It is imperative that the responsible engineer understands the potential accuracy limitations of the program results, independently cross checks those results with other methods, and examines the reasonableness of the results with engineering knowledge and experience.
  • There are no expressed or implied warranties.

I agree to these conditions when downloading the software.

Reporting Issues

If you believe you have found an issue with any version of the Hydraulic Toolbox (including installation errors, calculation errors, interface problems, confusing functions, errors and omissions in the User Manual, and anything else that might impact the functionality and usability of the software), please submit the following information to Ryan Lizewski (ryan.lizewski@dot.gov):

  • Name
  • Contact info (this won't be used unless there is a question about your Toolbox issue)
  • Computer operating system (Windows 8, Windows Vista, etc.)
  • Complete description of each issue
  • PLEASE attach the Toolbox project file (.hyd) that demonstrates the issue
  • Also consider attaching a screen shot of the Toolbox window if applicable

Hydraulic Toolbox Version 5.2.0

Build date: October 18, 2022. Download Hydraulic Toolbox Version 5.2.0 (.zip, 87 mb)

Bugs addressed:

  • Fixed issue with report generation failing on names with quotes (‘ or “) in the name.
  • Fixed issue where bridge Scour’s abutment scour was zero with any scour entered into the contraction scour’s pressure scour.
  • Fixed issues where the incorrect governing value was bolded in the Bridge Scour’s Summary Table.
  • Fixed issue where the summary table was not using the special case maximum scour depth.
  • Fixed issue where the toggle to turn off the Bridge Scour’s abutment scour plotting was unresponsive.
  • Fixed issue with the web service connection for NOAA Atlas 14 data in the Rational Calculator.
  • Fixed issue with the Rational Calculator not correctly saving the 1 and 200 year data.
  • Fixed a few minor issues in the Bridge scour combo boxes.

Hydraulic Toolbox Version 5.1.4

Build date: August 9, 2021. Download Hydraulic Toolbox Version 5.1.4 (.zip, 98.5 mb)

Improvements made to this version of the software include the following bug fixes:

  • Fixed discharge entry in contraction scour for live bed condition.
  • Fixed rational method file saving and reading issue for 1-, 200-, and 500-year intervals.
  • Fixed gradation row display issue.
  • Fixed issue of editing profile names.
  • Fixed weir width and tailwater depth display issue.
  • Fixed crash when generating curb & gutter reports for inlets in sags.
  • Fixed issues with writing detention basin calculations to the report file.
  • Added notes to the culvert riprap calculator.
  • Fixed digital gradation dialog resizing issue.
  • Updated combo box size in the rational method calculator.

Hydraulic Toolbox Version 5.1.1

Build date: May 3, 2021. Download Hydraulic Toolbox Version 5.1.1 (.zip, 97.1 mb)

Improvements made to this version of the software include the following:

  • Updated user guide documentation.
  • Enhanced 508 compliance. The program can now be navigated with the keyboard with increased menu tools and navigation. Each dialog was reviewed for keyboard navigation. The documentation has been updated to follow 508 compliance by using formatting, style sets, and alternate text for images. The report generator was updated to use style sets.
  • Upgraded interface for high pixel density displays and interface icons.
  • Added option to display rock riprap gradations in inches, feet, or millimeters.
  • Added option to set default unit system and profile.
  • Upgraded to a new library to export data to the report generator with Microsoft Word format (DOCX).
  • Channel Calculator:
    • Fixed issue with unit conversion using cross sections.
    • Removed lining calculations from the Channel Calculator since these calculations are in the Channel Lining Calculator.
  • Channel Lining Calculator:
    • Modified the note in rolled erosion control product (RECP) field for ½ inch of erosion.
    • Fixed issue where Da/D50 leaves the range of computation resulting in a message "Root must be bracketed in Newton Raphson".
  • Weir Calculator:
    • Fixed issue with SI units reducing head or flow with each computation
    • Added "irregular weir" computations.
  • Rational Calculator:
    • Removed NOAA Atlas 2 data from states where NOAA Atlas 2 is available.
    • Added NOAA Atlas 14 online data to the Intensity-Duration-Frequency data.
    • Fixed issues with computing a rational hydrograph with small times of concentration.
  • Detention Basin Calculator:
    • Fixed issue with unit conversion.
  • Riprap Calculator:
    • Fixed issue with transferring data from the channel calculations.
  • Bridge Scour Calculator:
    • Fixed plotting large number of piers and subsequent overlapping scour holes.
    • Fixed logic determining Abutment Type A or Abutment Type B.
    • Altered gradation note to be consistent with HEC-18.
    • Removed incorrect note about Meyer-Peter and Muller method.
    • Created channel width note for removing pier widths to indicate that the pier widths have been removed when exported by SMS.
    • Added 2 significant figures for Energy Grade Line Slope.
    • Fixed issue with abutment scour elevation.
    • Fixed issue with length of embankment visibility.
    • Added option to specify clear-water or live-bed contraction scour in the NCHRP abutment scour computations.
    • Added note in pier scour "if L/a > 12, use 12".
    • Fixed issue with no computed answer.
    • Fixed issue with negative scour depths being used in the scour summary table.
    • Fixed issue with pressure scour with multiple scenarios not being correctly added to the scour summary table.
    • Fixed issue with computing an eroded cross section with a NCHRP abutment in Scour Condition A.
    • Changed the default abutment type to be spill through.
    • Fixed unit conversion issue when importing a HEC-RAS file.
    • Added a new variable in pressure flow: "Depth at upstream bridge face".
    • Fixed error in note for cohesive soil limit (fixed from noncohesive soil limit).
    • Fixed issue with showing correct computed values in the scour summary table.
    • Modified report generator to export all scenarios instead of only the selected scenario.

Hydraulic Toolbox Version 5.0

Build Date August 21, 2020. Download Hydraulic Toolbox Version 5.0 (.zip, 42 mb)

Improvements made to this version of the software include the following:

  • Added new Interface colors.
  • Added multiple scenarios.
  • Created additional linkage with the Surface-water Modeling System (SMS) software.
  • Updated documentation.
  • Fixed the following bugs:
    • issue where zeroes were added in the bridge deck definition instead of blanks
    • incorrect note in the summary table
    • D50 changes and the summary table did not update correctly
    • user-defined channel incorrectly converted and saved the stationing and elevations
    • abutments not computing when all input was entered
    • abutment was computing a Type B condition when it was clearly a Type A
    • abutment did not compute Type B condition correctly
    • issue with abutment's station not being correctly used
    • removed scour reference point for abutments in bridge scour calculator
    • unit weight of water was improperly converted in metric
    • note for gradation limits needed clarification
    • additional significant figures for the EGL were needed
    • adjustments were needed for hydraulic conditions for scour computations when exported from SMS
    • contraction scour labels required clarification
    • a delete pier button with verification was needed
    • water surface elevations to bridge scour plot were added when exported from SMS
    • issue with pile cap component computation in complex pier computations
    • issue with minimum time of concentration in the IDF calculator
    • issue with exporting cross sections from SMS with 'no data'
    • issue with grate flow area when the grate is not fully submerged
    • reading issue in bridge pier scour

Hydraulic Toolbox Version 4.4

Build Date July 10, 2018. Download Hydraulic Toolbox Version 4.4 (.zip, 47 mb)

Improvements made to this version of the software include the following:

  • General issues:
    • Updated the code so it is easier to interpret and performed general maintenance and software updates.
    • Fixed scripting errors in the Map Viewer.
    • Modified the Report Generator to: correct an issue where a report was generated without computed results; correct some output labels; and change the report generation library files for each version of Hydraulic Toolbox to be unique (this prevents errors when installing and uninstalling different versions of FHWA software).
  • Ditch Inlet Calculator: adjusted calculations to better accommodate non-trapezoidal channel shapes.
  • Curb and Gutter Calculator: fixed incorrect depth calculations at the curb with a complex gutter (the calculator would compute the wrong depth when the width of spread was less than the gutter width in a complex gutter).
  • Detention Basin Calculator: corrected a computational instability issue and addressed a bug with determining the smallest flow to capture in the routing computations.
  • Bridge Scour Calculator:
    • Changed the calculator to perform computations as a bridge scour project instead of individual bridge scour components.
    • Added user options for scour hole computations and improved the plotting of bridge geometry and scour results.
    • Improved the capability to import variables and files from hydraulic models including HEC-RAS.
    • Added an option for the user to specify a depth for long-term channel degradation.
    • Fixed an issue where density was not properly converted in the contraction scour interface.
    • Added a warning for the Bridge Scour’s Pressurized Contraction Scour calculation if the bridge deck is not submerged.
    • Fixed a few specific issues with abutment scour: added user ability to specify the abutment scour condition location; fixed an abutment scour bug related to computing if the scour condition is occurring in the main channel or in the overbanks; and fixed an issue with some variables not properly being converted in the abutment scour interface.
    • Fixed a few specific issues with pier scour computations: corrected the length to width (L/A) for a pier to not exceed 12; corrected an issue with spacing and angle of attack for pier geometries defined by multiple pile rows and columns; and added appropriate warning messages and corresponding references to HEC-18 for more information.
Updated: 11/10/2022
Federal Highway Administration | 1200 New Jersey Avenue, SE | Washington, DC 20590 | 202-366-4000