Post-Processing: Creating Inundation Maps with very Large Terrain

We often have to deal with very large models covering hundreds of river miles.  The terrain data associated with these models can be equally massive, which can cause memory/processor issues when trying to delineate inundation maps. This post is not concerned with pre-processing our model geometry. Instead, we have a completed model with results we […]

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HEC-RAS 2D Training in Australia!

The 2D HEC-RAS class is a GO!  Who wants some HEC-RAS 2D Modelling training?   This will be a fantastic opportunity to learn how to set up and run 2D and 1D/2D HEC-RAS models.  Mr. Krey Price and I will be hosting this course in Melbourne, Australia on April 5, 6, and 7th. Please go here for […]

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HEC-RAS 5.0 versus TUFLOW versus MIKE21 – HEC’s official response

In case you haven’t seen it, there has been a very popular LinkedIn discussion on the Hydraulic/Hydrologic Modeler’s Forum debating the advantages, disadvantages, and merits of HEC-RAS 5.0, TUFLOW, and DHI’s MIKE21.  There was a lot of great information (and some misinformation) and insight provided in that thread.  It is well worth the read.  Some […]

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Pressure and Weir Flow

Here’s a video of pressure and weir flow yesterday at a bridge near my house.  This was brought on by some very intense rainfall over a short period of time.  What do you think the weir coefficient would be? ‘Tis the season in many parts of the world for heavy rains and high water.  This […]

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Breaking the HEC-RAS Code – 1 Year!

Well it’s been one year since I published “Breaking the HEC-RAS Code”.  It was a lot of work, but I am very pleased to see how many people are making use of the book controlling and automating HEC-RAS with their own codes.   For those of you who haven’t discovered it yet, this book introduces […]

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Transect for Extracting Flow in a 2D Area

*Update:  Version 5.0.2 now does flow transects in RAS Mapper with profile lines.  No longer necessary to use a 2D Area Connection to do this. A very common output request in 2D modeling is for flow over (through) a transect line.  HEC-RAS 5.0 does not have a specific tool for extracting flow data along a […]

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Combining Two Reaches or Splitting One

Suppose you have two separate HEC-RAS rivers and wish to combine them.  There is no “combine two rivers” option in HEC-RAS, but it can be done using the Move Points/Objects option.  Take the very simple reach presented below: I wish to combine the Upper Tualatin with the Clackamas reach of the Willamette River.  In the […]

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Using User-Defined Curves for Gates

HEC-RAS allows for four different gate types that will compute the stage-discharge relationship of that gate for you based on the physical size/shape of the gate and a few empirical coefficients:  Sluice Gates, Radial Gates, Overflow Gates (closed top) and Overflow Gates (open air).  However, sometimes the built-in gate types don’t quite fit the gate […]

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Windows 8 Compatibility Issues

If you are a Windows 8 user and you are having trouble getting HEC-RAS Version 5.0 beta to work, Window’s Program Compatibility Troubleshooter may solve the problem.  Problems usually arise when pressing the compute button.  One common message that pops up is “Error starting process. Steady file not found.”  The Program Compatibility Troubleshooter will fix […]

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