HEC-RAS Model with 2D Mesh Only.

Written by Christopher Goodell, P.E., D.WRE
Copyright © The RAS Solution 2015.  All rights reserved.

There have been many questions lately about whether HEC-RAS 5.0 can perform a simulation with ONLY a 2D mesh (i.e. no cross sections).  The answer is yes.  In fact, in many ways it’s a lot easier.  In this example, the standard Muncie project offered by the Hydrologic Engineering Center has been converted first to SI units, then to a single 2D mesh.  To keep things simple, the levee breach was removed and flow moving into the overbank areas is purely due to overtopping of the levee.  The following figure presents the geometry file for Muncie when modeled with a single 2D area.   




Once you’ve drawn your 2D area boundary and have assigned a mesh cell center spacing (DX and DY) and Manning’s roughness value(s), really all that is left is to

Updated Errata Sheet for Breaking the HEC-RAS Code.

For all of you who have a copy or are planning to get a copy of "Breaking the HEC-RAS Code", there's an updated Errata Sheet on the bottom of the "Book" page of this blog.  Although I spent a LOT of time hunting down and correcting errors before publishing, it's inevitable that some of these will show up.  As always, please let me know if you find any more.

And also, many of you have already emailed me with examples of code you've written by using the techniques presented in the book.  I love it!  Thanks.  Keep up the good work and if you've written something you think will be useful to others, or you just want to show off :-), please post it in the forum under the HECRASController sub-forum.

New HECRASController Forum

Happy New Year RAS Modelers-

I've added a new sub-forum for HECRASController users to post questions and comments specific to the HECRASController and to submit sample code that you would like to share with others.  As you do more and more programming with the HECRASController, please consider sharing some of your useful code with others.  I plan to periodically post code both from the book "Breaking the HEC-RAS Code", and from real projects I've worked on.  A good primer for controlling HEC-RAS using the HECRASController is located here.

The new forum can be found in the forum tab on the top of this page, or by following this link.  "Breaking the HEC-RAS Code" is available from my e-store and from Amazon and other on-line book retailers.

Have fun!

Including Channel Bathymetry into your Terrain.

Written by Christopher Goodell, P.E., D.WRE  |  WEST Consultants
Copyright © The RAS Solution 2014.  All rights reserved.

Let’s say you have a digital terrain model of the area you want to model with 2D HEC-RAS.  ONLY 2D RAS.  In other words, you want to lay out a grid, but do not want to have do to any 1D computations-all 2D.  The problem is the area you want to model includes one or more rivers and streams that have no bathymetric (under water topography) data represented in the digital terrain model.  This is a common problem as many sources of terrain data are collected today using LiDAR (Light Detection And Ranging).  As great as LiDAR is for collecting surface data, conventional forms of LiDAR do not penetrate water. 

To adequately model 2D in RAS,

11th National Hydrologic Warning Council Training Conference and Exposition-Call for Abstracts

The Call for Presentation Abstracts for the 11^th National Hydrologic Warning Council Training Conference and Exposition is now available. Scheduled for June 16-18, 2015 in Indianapolis, IN, the event will highlight “Advances in Hydrologic Warning – The Race to Save Lives.”

Retrieving Output Automatically

Written by Christopher Goodell, P.E., D.WRE  |  WEST Consultants
Copyright © The RAS Solution 2014.  All rights reserved.
Did you know that there are 268 output variables that you can retrieve automatically using the HECRASController?  That’s right, everything from velocity in the main channel, to shear stress, to stream power, to hydraulic depth, and of course water surface elevation.  There’s more than you can possibly ever want or need.  The post “Automating HEC-RAS” demonstrates how to get started with this.  To access any of the 268 variables, you can use the HECRASController Output_NodeOuput subroutine or the Output_ReachOutput function.  Both of these are described in detail in “Breaking the HEC-RAS Code”.
Here’s just a sample of the variables and their respective IDs. 

“Using HEC-RAS for Dam Break Studies”

Written by Christopher Goodell, P.E., D.WRE  |  WEST Consultants
Copyright © The RAS Solution 2014.  All rights reserved.

HEC recently published a new training document called “Using HEC-RAS for Dam Break Studies”.  Written by Gary Brunner, P.E., D.WRE, it is an easy to follow guide for performing Dam Break simulations in HEC-RAS.
 
It covers topics like: