HEC-RAS includes a suite of hydraulic and sediment transport calculators called the Hydraulic Design tools.  These tools are HEC-RAS post-processors that use results from 1D steady and/or unsteady hydraulic computations to perform common, classic, or simplified analyses for hydraulic design or sediment transport problems.

This suite of tools is actively expanding, including a new Riprap Calculator in version 6.1, with more planned for upcoming versions.

To use one of the Hydraulic Design Calculators press the HD button , or select the Run → Hydraulic Design Functions menu from the main HEC-RAS editor.  The HD editor automatically opens to the Bridge Scour tool.  To select any of the other HD calculators, select the Type menu and choose one of the other options.

The Hydraulic Design tools currently include the following six hydraulic and sediment transport calculators:


Bridge ScourApplies the US Federal Highway Administration's bridge scour equations and algorithms from HEC-18 to a steady flow hydraulics profile 

RiprapComputes a stable rock size for bank protection using the USACE guidance in EM 1110-2-1601 and applies a suite of general and bend scour equations to help design toe protection.

Uniform FlowA normal depth calculator, that allows users to apply manning's equation to compute a hydraulic geometry without a full HEC-RAS model. 

Stable Channel DesignA suite of tools (including tractive force, Lane, and Copeland methods) that compute the hydraulic geometry that is in transport equilibrium with the flow and sediment in a channel, or visa versa.

Sediment Transport CapacitySimplified calculator that computes sediment transport capacity for a steady flow profile - with a suite of sediment transport equations - ignoring supply, flux, or feedback that make a sediment transport model both more useful, and more difficult.

SIAMThe Sediment Impact Analysis Methods is a sediment budget tool that uses steady flow results from HEC-RAS, transport functions, and user specifications of watershed and point-source loads to screen sediment impacts alternatives on a watershed scale. 

Sediment Rating Curve Analysis Tool

Imports sediment load, concentration, and load-gradation data and leads analysts through common statistical and conceptual analyses to help them fit an appropriate rating curve through the data cloud.