Month: April 2022

When I am manipulating station-elevation data for HEC-RAS, I often do this in Microsoft Excel. However, it can be tedious to copy and paste data for each cross-section into the Geometric Data Editor. In order to solve this problem, I used the HEC-RAS Controller to write a macro in Excel that automatically creates an updated … Read more

RAS Mapper has allowed hydraulic modelers to more easily perform Geographic Information System (GIS) operations. Many people think that the RAS Mapper and the Geometric Data Editor will eventually merge into one interface. If you want to use this increasingly popular feature in HEC-RAS (RAS Mapper), you must add a projection to your HEC-RAS project. … Read more

Preparing a stable unsteady HEC-RAS model is a common problem among hydraulic modelers. This is particularly true when preparing a dam-break model in HEC-RAS. An unstable HEC-RAS model results in numerical errors that grow until the results start to oscillate. As a result, the errors grow until the model computations cannot continue. There are many … Read more

Lately, I have been working on several dam inundation studies. As part of this work, I have been developing HEC-RAS models to route breach flows through the downstream area. HEC-RAS Version 5.0.5 allows users to culverts to 2D Flow Areas. However, modeling every bridge or culvert in HEC-RAS can be very time-consuming. The good news … Read more

I am working on a one-dimensional (1D) dam-break model in HEC-RAS this week. Typically, I work with 2D HEC-RAS models, so this project has been somewhat challenging. Cross-section placement is an art, and I am slightly out of practice. Anyways, I have been having issues stabilizing the model. This is not an uncommon problem for … Read more

Preparing a stable unsteady HEC-RAS model is a common problem among hydraulic modelers. This is particularly true when preparing a dam-break model in HEC-RAS. An unstable HEC-RAS model results in numerical errors that grow until the results start to oscillate. As a result, the errors grow until the model computations cannot continue. There are many … Read more

If you have been using HEC-RAS for a while, there is a good chance that you have run into the “disappearing terrain” issue. Yes, I am talking about when your background terrain disappears from the Geometric Data Editor. Although it is annoying, this is a fairly common problem. Fortunately, I am going to share some … Read more

According to “Hydraulic Design of Safe Bridges” (FHWA, 2012), skew is defined as “a condition when a bridge opening is not perpendicular to flow or when a pier is not aligned with the flow.” It is important to account for the bridge skew angle because it can affect the amount of backwater at the bridge, … Read more

Introduction This blog post will introduce the steps involved in performing a simple sediment transport analysis using the HEC-RAS program.  HEC-RAS is capable of mobile boundary, and sediment transport modeling. A boundary is mobile when flow carries a lot of sediment through suspension and is in contact with the streambed. In these cases, the following … Read more

Boundary conditions are an important part of hydraulic modeling as they allow hydraulic modeling programs such as HEC-RAS to begin performing water surface profile calculations. In HEC-RAS, users enter boundary conditions in the Steady Flow Data Editor and the Unsteady Flow Data Editor. The following article is an introduction to applying boundary conditions in HEC-RAS … Read more