New Book - “Breaking the HEC-RAS Code” now available!

 
One of the most powerful, yet relatively unknown features available in HEC-RAS is the HECRASController.
The HECRASController API has a wealth of procedures which allow a programmer to manipulate HEC-RAS externally by setting input data, retrieving input or output data, and performing common functions such as opening and closing HEC-RAS, changing plans, running HEC-RAS, and plotting output. HECRASController applications are seemingly endless.  Not only can the retrieval and post-processing of output be automated, but with the HECRASController, real-time modeling and probabilistic experiments are possible. If you have HEC-RAS on your computer, you already have the HECRASController!
“Breaking the HEC-RAS Code” explains how the HECRASController works, provides example applications of the HECRASController, and catalogs the vast array of programming procedures (with explanations and examples on how to use them) embedded in the HECRASController.
This is a "must-have" book for all HEC-RAS users.

Automating HEC-RAS!

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

Are you an HEC-RAS user?  Yes?  OK, try this out:

1.  If you haven’t already done so, install the HEC-RAS example projects to the default location.




2.  Open up a blank workbook in Excel.

Sediment Transport Quasi Unsteady Flow Editor Flow Series Error

Written by Chris Goodell, P.E., D.WRE  |  WEST Consultants
Copyright © The RAS Solution 2014.  All rights reserved.
“Flow or Temp time series date is not sufficient to run requested time window.”  This one has been around for a while, but it just showed up again on the Facebook HEC-RAS User’s Group, so I thought I’d show the fix(es) here.  This applies to the new beta version of 5.0, as well as previous versions of HEC-RAS that can run sediment transport. 
When running a sediment transport model, if this error message pops up, there are at least three possible reasons.

1.  Make sure you have both flow AND temperature time series data. 

Re-Projecting HEC-RAS Model Geometry

Written by Sarah Bengtson  |  WEST Consultants
Copyright © The RAS Solution 2014.  All rights reserved.




HEC-RAS 5.0 now provides a tool for quickly re-projecting model geometry within RAS. It is accessible from the main RAS interface under the Options menu…Convert Horizontal Coordinate Systems.


 


From this window, the user must select the Current Project Spatial Reference System and the Destination Project Spatial Reference System by loading the appropriate projection file (*.prj) for each. Do not confuse this file type with an HEC-RAS project file (also *.prj).  Once the projection files are loaded, click OK.

Updated HEC-RAS Version 5.0 Beta Now Available

HEC has just released an updated beta version of HEC-RAS 5.0.  This is the third and final beta release before the final release due out in January 2015.  This new release takes care of most of the bugs that have been reported and includes some nice new features like spatially varying Manning’s n values for 2D areas, Velocity plotting for 1D and 2D areas, and improved hydraulic structure connections for 2D areas. Please read the new User’s Manual.  It is very well written and informative. 
Please read the release letter below for directions to download the latest version.  As always, if you find bugs or have suggestions for Version 5.0, please submit them to The RAS Solution forum here.
 
Dear HEC-RAS 5.0 Beta tester,
     You are receiving the this email, and a link to an updated version of "HEC-RAS 5.0.0 October, 2014 Beta (with 2D Flow Areas)", because you are either a previous Beta tester, or you have expressed interest in the new 2-Dimensional modeling capabilities being added to HEC-RAS.  Several new features have been added and many bugs have been fixed since the last Beta release.  The main new features are: Spatially varying Manning’s n values for 2D Flow Areas; Velocity plotting for 1D and 2D areas; and improved hydraulic structure connections for 2D Flow Areas.  There is an updated User’s manual that describes these new features, as well as other changes, that is contained in the self extracting zip file that you will download.  Please read the new User’s manual!  There are also two data sets that come with this setup package that demonstrate most of the aspects of using 2D Flow Areas.  The data set called “Muncie.prj” has an example of how to use spatially varied Manning’s n values for 2D Flow Areas.  Use that data set as a guide, along with the User’s manual to learn how to use this feature. 
Here is the link to the latest version:
http://www.hec.usace.army.mil/misc/files/ras/HEC-RAS_5.0_Beta_2014-10-01.exe
      This link lets you download a self extracting archive file called "HEC-RAS_5.0_Beta_2014-10-01.exe" 
      Download the file to a separate directory and run the self extracting archive file.  The self extracting archive file contains:
            1). The installation setup package called: " HEC-RAS_5.0_Beta_2014-10-01_Setup.exe"
            2). A updated PDF version of the User's Manual called "Combine 1D and 2D Modeling with HEC-RAS.pdf"
Here is a separate Link to the new 1D/2D User’s manual, if you want to download it separately:

http://www.hec.usace.army.mil/misc/files/ras/Combined_1D_and_2D_Modeling_with_HEC-RAS.pdf
            3). Two 2D Test Data sets in a directory called "RAS_50 Test Data"
      I provided a link to the updated version of the User's Manual on how to use the 2D modeling capabilities within HEC-RAS 5.0 Beta ("Combine 1D and 2D Modeling with HEC-RAS.pdf").  This document has been dramatically expanded.  If you really want to learn how to use the 2D modeling capabilities in HEC-RAS, Please Read This Manual.  I have spent a lot of time working on this document, and I think anyone who currently knows how to use HEC-RAS for 1D unsteady flow modeling will be able to learn how to use the new 2D unsteady flow modeling capabilities with just the software and this document.  Please give me some feedback on this User’s manual if you find mistakes or there is information you feel is missing, or could be explained better.
            There are two example data sets that come with the self extracting zip file: “Muncie.prj” and “BaldEagleDamBrk.prj”.  The Muncie data set is a 1D river with a 2D Flow Area inside of a Levee system.  The levee system is breached and flow goes into the protected area.  The Muncie data set also contains spatially varying Manning’s n values for the 2D Flow Area.  The BaldEagleDamBrk data set has seven different Plans in it.  This data set has examples of all the different ways to use 2D areas.  The purpose of this data set is just to demonstrate all the different Ways 2D areas can be linked to 1D elements, as well as modified computational mesh examples, and hydraulic structures inside of a 2D Flow Area.
            This will be the last Beta version of HEC-RAS 5.0.  Our “plan” is to have a final release of HEC-RAS 5.0 in January 2015.  So, we need you to test this version of the software and provide us feedback. 
      Thank you for testing HEC-RAS, we look forward to your comments and feedback.
Gary W. Brunner, P.E., D.WRE, M.ASCE
Senior Technical Hydraulic Engineer
Hydrologic Engineering Center. USACE
(530) 756-1104
www.hec.usace.army.mil

HEC-RAS 2D Updates Coming!

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

(Update:  New release is now available here)

Just heard from HEC that a new, updated beta version of HEC-RAS 5.0 will be coming out soon (later this month or early next).  The full release of HEC-RAS Version 5.0 is still scheduled for the end of the calendar year. 

New features in the next beta release are:

1. Multiple Manning's n value definition in 2D areas
2. Velocity Vectors in RAS Mapper
3. Particle Tracking Visualization Tool in RAS Mapper

Plus most (if not all) of the bugs found to date will be fixed.

Here’s a sneak peak of a new velocity visualization feature in HEC-RAS used in an “instantaneous” dam break example, courtesy of Gary Brunner.

(The YouTube Link will offer a better quality video)

https://www.youtube.com/watch?v=-lZkE0IPj0c&index=1&list=UUgkWjGRSy2Vc_wqdX-sC5rA

Creating your mesh in RAS 2D

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

Your computational mesh is what will allow you to do 2D modeling in HEC-RAS.  Think of a mesh as a net that you drape over your terrain.  The continuous properties of the “infinite” terrain are then discretized onto the mesh so that computations can be made over a finite domain.  Here in the geometry editor, we can see the computational mesh “draped” over the terrain.  Notice that the mesh remains within the perimeter of the terrain.  This is required for HEC-RAS.  RAS is able to work with structured or unstructured meshes with cells that have up to eight sides.  Typically you’ll begin with a Cartesian or rectilinear structured mesh and where you add more detail and resolution, you’ll have unstructured (irregular) zones within your mesh.  Boundary cells will also exhibit unstructured characteristics where RAS works to fit the mesh to the mesh perimeter.





Before building your mesh, it can be useful to include a background image of your terrain so that you can make sure you draw your grid within the bounds of your terrain. The background image will also give you a clue about areas in your 2D grid that might need more or less detail. The background image has to be created external to HEC-RAS and must be accompanied by a world file. More information about world files can be found here: http://webhelp.esri.com/arcims/9.2/general/topics/author_world_files.htm




Use the 2D Flow Area button at the top of the geometry schematic to draw a new 2D area. This is drawn exactly the same way storage areas are drawn. Single click the points to define a polygon shape, staying within the bounds of the terrain (very important), and to complete the area, double click.


Once a 2D area has been defined, click on the 2D Flow Area editor button to set up the mesh. The first windows provides the user options for Manning’s n value for the 2D Area. Only 1 n value can be used for now in the 5.0 beta version of HEC-RAS for a 2D Area, but future versions will allow multiple n value definition for a single 2D Flow area. The tolerance input boxes allows the user to have some control on how much data goes into each of the cells on the soon-to-be-created 2D grid. The defaults usually work very well for the tolerance inputs. Typically you’ll enter the Manning’s n value and then click the “Generate Computation points on regular interval. Then go ahead and define the grid cell size (both width, DX, and height, DY). The starting offset point is optional. Default is to leave it at 0,0. Then click “Generate Points in 2D Flow Area, and HEC-RAS will build a structured mesh of constant cell size (this can be adjusted later).


Here we can see the mesh that was created with 500 ft X 500 ft spacing. Notice that the majority of the mesh was created with 500-ft by 500-ft square cells, but around the perimeter of the 2D area, RAS automatically creates irregularly shaped cells to fit the edges. These should always be checked after the mesh is created to make sure the edge cells are suitable. Look for cells with multiple centers, or cells that are not generally the same size and aspect ratio as the others (like the example highlighted above).


You can fine tune your mesh (either correcting unsuitable boundary cells or adding more detail/resolution) by using the “Move”, “Add”, and “Remove” tools in the Edit menu of the Geometry Schematic.  After you select Edit…Move Points/Objects, you can click and drag any of the cell center points.  Once you “de-select” Move Points/Objects, HEC-RAS will redraw the grid based on the new, manual placement of centers.





In addition to moving cell centers, you can add more cell centers to your mesh where you need more detail, and remove cell centers where you need less detail. For example, in this narrow connection between two flooded areas, we want more definition to better simulate the flow through here. Manually click some points where more definition is needed. Once “Add Points” is unchecked, HEC-RAS will automatically redraw the grid. Where you move points or add more points, the mesh will look a lot less structured.  



Look closely at this last figure.  We have a nice structured grid in the large floodplains to the northwest and southeast.  The narrow connection between the two exhibits a very unstructured mesh with more detail.  There are (at least) two things wrong with the grid.  In fact, these two things will prevent RAS from running until they are resolved.  Post a comment below and let me know what you think the errors are. 


More information on 2D modeling in HEC-RAS can be found here:  https://drive.google.com/file/d/0B_s8OLJOgOi0Nm5sdHFhSzFUYkk/edit?usp=sharing

Images in this post are from the Bald Eagle Creek Example Dam Break Study example data set.  The Bald Eagle Creek Example Dam Break Study HEC-RAS model is provided courtesy of the Hydrologic Engineering Center and can be downloaded along with HEC-RAS Version 5.0 beta here: http://hecrasmodel.blogspot.com/2014/10/updated-hec-ras-version-50-beta-now.html