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Washington, DC 20590

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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 32-bit program, but it is fully compatible with 32 and 64-bit Windows-based operating systems (XP, Vista, Windows 7, and Windows 10) and runs in 32-bit mode on these 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 if running Windows Vista or Windows 7. Windows XP users should login to an account that allows you to install software before installing the Toolbox.

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

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.

Hydraulic Toolbox Version 4.3

Note: Hydraulic Toolbox Version 4.3 was released internally to FHWA staff as a Beta version for testing. Version 4.4 implements Version 4.3 features as well as additional functionality. Version 4.3 will not see an external release.

Hydraulic Toolbox Version 4.2

Build Date August 18, 2014. Download Hydraulic Toolbox Version 4.2 (.zip, 40 mb)

Improvements made to this version of the software include bug fixes to the bridge scour calculators and the addition of a project mapping module. The scour calculators follow the procedures presented in Hydraulic Engineering Circular 18 (HEC 18), Evaluating Scour at Bridges, Fifth Edition, 2012. The mapping module allows users to identify the location(s) of any analyses conducted within the Hydraulic Toolbox software on a user supplied image or an image taken from current aerial photography (internet connection required). It also allows ground photos to be attached to each analysis location, as needed or desired.

Updated: 12/04/2018
Federal Highway Administration | 1200 New Jersey Avenue, SE | Washington, DC 20590 | 202-366-4000