Monday, November 4, 2019

McBreach Probabilistic Dam Breach Modeling - Free Webinar

ICEWaRM will be hosting this free webinar where I'll be discussing the software program McBreach and its application to probabilistic dam breach modeling.  Come join in!  Please note the the webinar start time for your particular time zone.  Starts at 10:30 AM local Sydney Australia time on Wednesday, Nov 6th.  That is 3:30 PM on Tuesday, Nov 5th if you live on the west coast of the USA.  Find your local time.  After the webinar, get your free copy of McBreach and the User's Manual here.




Manage risk by leveraging the power of HEC-RAS through Monte Carlo simulations

Introducing McBreach! Faced with aging infrastructure, limited resources, dynamic weather events, and the uncertainty of climate change, today’s dam owners must manage risk to protect the lives of the public and our built environment. The free McBreach program, quantifies uncertainty and informs better decision making before an event.


“McBreach takes dam breach modelling and analysis to the next level. By complimenting the traditional deterministic dam breach methods, McBreach’s probabilistic approach provides a more meaningful and more genuine way to communicate the potential effects from a dam or levee breach.” says Chris Goodell, Principal Consultant for Hydraulics & Hydrology, Kleinschmidt.

Thursday, October 24, 2019

HEC-RAS in Three Dimensions

Now this is the kind of post that gets you on The RAS Solution!  Cutting edge creative solutions to complex problems.  This is great stuff.  Thanks Michael for all the effort you put in to this.

Written by Michael Link | AECOM
Copyright © The RAS Solution.  All rights reserved.  

In today’s post we’ll cover two methodologies that leverage HEC RAS results to create impressionable and multi-dimensional flood visualizations. If these methodologies are implemented industry-wide, it is likely that the public will become more engaged with our work and our clients wowed. Products of the two methods are shown below.

Figure 1: 3DV-Flo Output of Muncie, Indiana (left) and 3D Printed Flood of Puerto Rico (right)

Introduction
The mitigation of flood risk is traditionally accomplished through regulation, correct science, and public buy-in. The federal government writes the regulation, we make the floodplain maps, and homeowners begrudgingly purchase flood insurance. How can we as engineers change the public’s sentiment towards our work and how can we further reduce infrastructure damage? One way we can do this is by transforming HEC RAS results into a format that is visually stimulating and easily digestible for nearly anyone. 

FIRM maps, WSEL/Depth rasters, and inundation boundaries serve the purpose of communicating information but do not necessarily communicate flood risk in a simple and powerful manner. This post is targeted at transforming RAS results into just that, a simple and powerful resource for capturing the attention of the public. If flood risk is internalized by communities, we can expect infrastructure loss to decrease and funding for our line of work to increase. Let’s dive in!

3DV-Flo (3D Visualization of Flooding)
3DV-Flo is a methodology that takes in RAS results and generates a 3D flood visualization in Google Earth. Here are a few examples of 3DV-Flo output.

Figure 2: Austin, Texas flooding visualized with 3DV-Flo


Figure 3: Google Street View of 3DV-Flo output


Figure 4: Muncie, Indiana flooding visualized with 3DV-Flo

The following YouTube playlist shows examples of 3DV-Flo output (the first video in the playlist is embedded below).  If you would like to explore the output yourself in Google Earth, the non-regulatory KML’s can be downloaded here.



3DV-Flo allows the information stored in WSEL and depth rasters to be viewed three-dimensionally in Google Earth. This output is an improvement upon RAS Mapper generated KML’s in that the results are no longer clamped to the ground. The 3DV-Flo method relies on three inputs (an inundation boundary, depth raster, WSEL raster), two free software (HEC-RAS, Google Earth), and one proprietary software (ESRI ArcGIS*). The 3DV-Flo toolbox has been tested on ArcMap for Desktop versions 10.3.1 and 10.6.1. Compatibility of this toolbox cannot be guaranteed with ArcGIS Pro or other Desktop versions. Additionally, there are two model types within the 3DV-toolbox. The first uses tools from the Advanced ArcGIS License. The advanced model is slightly faster and provides the functionality of adding breaklines to your resulting mesh. Breaklines are helpful for modelling levees, elevated roads, and dams. The second model uses tools solely from the Basic ArcGIS license, but you must have the 3D Analyst and Spatial Analyst extensions activated as described in this ESRI post. If this tool has a red ‘X’ next to it in ArcGIS follow the steps discussed in this video.

Assuming you have a georeferenced 1D or 2D RAS model and access to ArcGIS, let us proceed with the tutorial. You can follow along with the video below or you can scan the detailed written instructions.
*3DV-Flo methods are currently dependent on ESRI ArcGIS. These methods can surely be recreated in QGIS or in a standalone script given enough time and ingenuity. Any individual with the time and desire to make this a fully open-source method can reach out to Michael Link for further guidance. 


3DV-Flo (3D Visualization of Flooding) Steps:


                  1.  Download 3DV-Flo Files

a.       Download 3DV-Flo zipped files from Github here

                  2.  Within HEC RAS

a.       Open geo-referenced HEC RAS project
b.       Open RAS Mapper
c.       Import best available terrain if not already there
d.       Right-click results and click ‘Add new results layer’ for the max inundation boundary, depth raster, and WSEL raster
e.       Compute/update layers
f.        Export break lines as shapefile if applicable

                  3.  Within ArcGIS

a.       Open blank MXD
b.       Import model output (inundation boundary, depth raster, WSEL raster, and breaklines) to MXD
c.       Import symbology shapefile. Adjust symbology to be blue with no border and displayed with a transparency of 40%
d.       Open the 3DV-Flo toolbox by navigating there in ArcCatalog
e.       Open the 3DV-Flo_WSEL tool
                                                               i.      The 3DV-Flo_Depth tool is used to reference flood depths to the ground rather than to mean sea level. This tool can be used when the vertical datums between RAS and Google Earth differ.
                                                             ii.      To use this tool right click the KML in Google Earth, click properties, click altitude, and switch the altitude to be ‘relative to ground’
f.        Populate tool parameters and specify where the Google Earth KMZ is to be saved
g.       If breaklines are not applicable, then bring in the ‘Arbitrary_Breakline’ shapefile from the unzipped folder
h.       Run 3DV-Flo tool

                 4A - Within Google Earth for Desktop

a.       Download software here if not installed on your machine
b.       Open Google Earth
c.       Click File>Import>and then navigate to the KMZ you created in ArcGIS

                 4B - Within Google Earth for Chrome

a.       Open Google Earth in chrome browser
                                                               i.      https://Earth.Google.com/web/
b.       Click three horizontal lines in the top left of window
c.       Click my places
d.       Click import KML file
e.       Click open file
f.        Navigate to KML file of interest and import

There are two known 3DV-Flo ‘bugs’. The first of which deals with poor terrains spatially restricting results. The second deals with 3DV-Flo output that appears unrealistically high in Google Earth. The first bug can be fixed by updating the underlying terrain. The second bug can be fixed by relating 3DV-Flo output relative to the ground rather than to mean sea level. These bugs and their respective workarounds are discussed in this video.

The vision for 3DV-Flo in the future includes 1. widespread adoption of the method by industry, 2. conversion of the entire US regulatory floodplain into 3DV-Flo format, and 3. the combination of 3DV-Flo with the National Water Model forecasts to help cities prepare for incoming floods. Advancing goal #1 is in part achieved through the readership of this post. Advancing goal #2 is theoretically possible by splitting the NFHL polygon layer nationwide by all XS’s with regulatory elevations. The resulting polygons could be transformed into 3DV-Flo output. Lastly, goal #3 has been prototyped in this video and this post. Any assistance to advance these goals is welcomed.

3D Printed Floods
According to the Wohlers Report 2019, the 2020 value of 3D Printing and Additive Manufacturing will be $15.8 billion! Can we get a piece of that??? One way that we can participate in this trend is to overlay RAS results onto 3D printed terrains. Here is a YouTube playlist link to some examples of just that for a pluvial flooding model of Puerto Rico (the first video in the playlist is embedded below).



The intended effect of this visualization is to intuitively convey how floods develop and where they pose the largest threat. 3D printed terrains are often presented at a large scale due to the coarse nature of the underlying digital elevation model. This visualization is unlikely to be used as a structure by structure evaluation of risk. It is more likely to be used in a city hall meeting or in the classroom. The Austin, Texas Watershed Concepts Group from AECOM was the first (to my knowledge) to prototype a 3D Printed Flood. Details on their FEMA funded San Marcos, Texas project can be found here. That same group generated a second 3D printed flood for Puerto Rico to give locals a high-level understanding of, go figure, watershed concepts. The projector and mount costed roughly $500. The San Marcos 3D print costed $1400 and the Puerto Rican model $250. The difference in price was related to print infill density and size.

If you are interested in making one of these models you can follow along with the video tutorial below and/or you can scan the detailed written instructions.


3D Printed Flood Steps:

                  1.  Develop 3D Printed Terrain

a.       Check 3D model repository (Thingiverse or Google searching 3D printed terrain of “Location”) to see if your location already has an STL 3D print file
b.       If there is no pre-existing STL file or you would like to make your own, you have a few options. 
                                                               i.      Create STL from the Terrain2STL (Ideal due to time saved and nonideal due to fixed rectangular shape of STL)
                                                             ii.      Create terrain from Touch Terrain (Ideal due to time saved and ability to specify bounding coordinates)
                                                           iii.      Create STL by converting Lidar to greyscale image (process described here) and load into Blender to convert the greyscale into an STL file (process described here).
                                                           iv.      More options detailed here.
c.       Modify STL file as needed in Meshmixer
                                                               i.      The most important functions in Meshmixer are:
1.       Edit > Plane Cut – This function allows you to discard unnecessary pieces of your model and to break your model down into smaller chunks to be printed by small 3D printers
2.       Edit > Transform – This function allows you to stretch your model solely in the Z direction. For more hash marks click the up arrow.
3.       Analysis > Units/Dimensions – This function allows you to rescale your model proportionally in all directions
d.       If you do not have a 3D printer at home or in the office, shop around to see where you can get the best deal. For prototyping, I found that 3D Hubs was the cheapest and easiest to use. Their banana reference was amusing and useful for catching extremely large or small prints. For the final 1.5-foot-long print of Puerto Rico, I used a local printing service so that I could guarantee the quality and interact with a human. Here is a list of the top 10 online 3D printing services in 2019.

                  2.  Develop Movie of Flooding in HEC RAS

a.       Download ShareX or comparable screen capture software
b.       Create or load a pluvial or fluvial model in HEC RAS
c.       Open RAS Mapper
d.       Load web imagery, terrain, or basemap to be displayed in movie
e.       Open ShareX and create screen capture video of unsteady RAS simulation


3.  Project Movie of Flooding onto 3D Printed Terrain
a.       Download VLC media player or comparable video software
b.       Open the flooding movie in VLC
c.       Connect the computer to projector via HDMI cable
d.       Setup a projector and table mount
e.       Pause flooding movie at peak flooding and calibrate the movie extent to 3D print extent by
                                                               i.      Raising or lowering the Pixar lamp stand
                                                             ii.      Adjust the aspect ratio of video
f.        Equipment setup is detailed further in this video
g.       Project flooding onto terrain with basemap


In Conclusion
As illustrated in this post, the impact of our RAS modeling can be greatly bolstered with spectacular Google Earth imagery and mesmerizing 3D prints. By presenting our clients and communities with these flood visualization resources, our work can be used outside of the narrow confines of designating whether someone should or should not buy flood insurance. 

Acknowledgements
The inspiration for the 3DV-Flo methodology would not have been possible without the catalysts listed below.
1.       a Scottish scientist’s Google Earth clamped-to-ground flood simulation
2.       a breakline/polygon GIS tool from Ryan Dalton
3.       a sea-level rise Google Earth tutorial from David Sadoff
4.       and a Google Earth flood simulation from Mariusz Krukay

Much gratitude goes out to Muhammad Ashraf and Yuxiang Kang for technical guidance and edits, John Wade for wise GIS counsel, Yacoub Raheem, Clint Kimball, and Justin Baker for patient 2D HEC-RAS Training, and Chris Wright for overall mentorship.


Contact Details:
For more information on this topic, please message Michael Link through LinkedIn - https://www.linkedin.com/in/michael-link-b88329118/

Michael Link works for AECOM in Austin, Texas.  He received a B.S. in Ecological Engineering from Oregon State University and an M.S. in Environmental and Water Resources Engineering from The University of Texas at Austin.  Michael is an EIT and certified floodplain manager.  Outside of work,  enjoys combining hydraulics, spatial analysis, and data science in novel ways.


Wednesday, October 9, 2019

2D HEC-RAS Class in Boise October 28-30

HEC-RAS Modelers!  Don't miss this opportunity for 2D HEC-RAS training in beautiful Boise Idaho.  I'll be teaching this class and hope to see you there!

There are limited seats for this class so don't delay in signing up.

This will be a three-day course with a mix of lectures and workshop exercises.  You will learn how to set up, run, and troubleshoot 2D and combined 1D-2D HEC-RAS models with an emphasis on river restoration projects.  Five separate workshops will give you practical experience setting up and running the software.



1D/2D Modeling with HEC-RAS
Professional Development Course

Purpose and Background
This intensive, workshop-oriented, three day seminar will prepare the engineer and water resource professional to use the HEC-RAS computer program for modeling two-dimensional (2D) and combined one-dimensional/two-dimensional (1D/2D) unsteady flow applications. Led by Kleinschmidt Associates, participants will learn how to approach and construct a 2D model for unsteady flow conditions, and to effectively view and analyze results. 

The seminar includes lectures on 2D flow theory, RAS Mapper, an introduction to the new capabilities and features of HEC-RAS, post processing and analysis of results, and procedures for creating a stable and calibrated 2D model.  Workshops focus on giving students hands on experience with building and pre-processing the computational mesh, performing offline and inline 2D projects, and using the built-in feature RAS Mapper to spatially analyze results. The seminar can also be customized to fit an organization or groups interest in areas such as dam breach analysis, river restoration, or rain-on-grid.


HEC-RAS incorporates various aspects of 2D hydraulic modeling, including floodplain hydraulics, dam and levee breaches, rain-on-grid applications, and the interaction between 1D and 2D systems.  Version 5.0.7 of HEC-RAS includes features in 2D open channel hydraulic analysis such as:
  • Two-dimensional flow analysis using the full St. Venant or diffusion wave equations in 2D.
  • Ability to perform a combination of 1D and 2D flow analysis in the same model.
  • The use of unstructured or structured computational meshes for the 2D flow areas.
  • Dam and Levee breaching in 1D and 2D areas.
  • Rain-on-grid modeling.
  • Full pre- and post-processing of geometry in 1D and 2D. 
Seminar Benefits/Learning Outcomes
  • Use the HEC-RAS (River Analysis System) computer program to model 2D and combined 1D/2D unsteady flow hydraulics.
  • Use RAS Mapper to pre-process both 1D and 2D geometric elements. 
  • Understand 2D flow theory and the differences between 1D and 2D modeling.
  • Gain hands-on HEC-RAS experience by participating in practical computer workshops.
  • Understand how to develop a stable and calibrated 1D/2D flow model.  
  • Know how to post-process and analyze 1D and 2D results. 
  • Obtain valuable insights in methods for minimizing computation errors and instabilities for 2D unsteady hydraulic models.  
  • Learn from real world projects and applications.
Who Should Attend
Consulting engineers, water resource planners, engineers employed by local, state, or federal government agencies. Participants should have some experience in floodplain hydrology and hydraulics, and some experience in HEC-RAS steady and unsteady flow computer modeling. They should also be able to follow simple computer instructions. 


DAY 1
  • Introduction to HEC-RAS 1D/2D Modeling
  • Building a 1D/2D Model
  • RAS Mapper
  • Computer Workshop on Creating a 2D Model
  • 1D/2D Flow Data
DAY 2
  • Computer Workshop on Channel and Floodplain Modeling
  • 2D Theory
  • Computer Workshop on Dam Breach
  • Performing Computations
  • 2D Output
DAY 3
  • Computer Workshop on Levee Breach Modeling
  • 2D Advanced Topics
  • 2D Modeling Stream Restoration
  • Computer Workshop on River Restoration

Friday, May 31, 2019

McBreach Probabilistic Dam Breach Modeling Software

Fellow HEC-RAS modelers. Today is National Dam Safety Day.  Dam Breach modeling is a key component to a well-rounded and robust dam safety program.  If you're doing dam breach modeling, you need to check out McBreach. Probabilistic hydraulic modeling is where we're heading with dam breach analysis. Why not get a head start with McBreach. This is free software and works seamlessly with HEC-RAS.  https://spark.adobe.com/page/RXu9m2OZJFOuc/

Thursday, May 23, 2019

HEC-RAS Pub and Grub in Portland-June 27th-Reminder and short video preview!


For those of you who will be in the Portland Oregon area on June 27th, I invite you to join me for this special event Kleinschmidt is hosting at the Lucky Lab on Hawthorne.  I'll be joined by two dynamic and entertaining presenters: Krey Price of Surface Water Solutions and Sean Welch of BPA.  We will be talking about the fun side of hydraulic modeling, demonstrating some wild, creative, and somewhat wacky applications of HEC-RAS.  

Agenda:
  • What's New (and Coming!) with HEC-RAS
  • Automating HEC-RAS with the HECRASController
  • How to know when your HEC-RAS model is wrong
  • Using drones and Structure from Motion to prepare terrain surfaces for your HEC-RAS models.  
  • Crazy and absurd (but fun!) applications of HEC-RAS around the world
  • 2D Modeling of the Ice Age Missoula Floods

You don't want to miss this!  

Check out Krey Price's preview video for the HEC-RAS Pub and Grub!



It will be an informal, casual gathering with lots of time for Q&A.  Hope to see you there!  No RSVP needed.  Just show up a little early, get a pint, and grab a chair.  We'll start at 5:30 sharp and we have the pub until 8:30.

  Space may be limited, so make sure you get there on time!



Wednesday, April 24, 2019

Those Nuisance Cell Errors and Wedge Depressions


Written by Chris Goodell | Kleinschmidt Associates
Copyright © The RAS Solution.  All rights reserved

If you've been doing some 2D modeling, you most likely have run into what I call nuisance cell errors.  You see them while your model is running and they can really slow down your simulation as the RAS chugs through iterations to try to come to a solution.

The errors here are in the second to last column and are in units of feet.  So as you can see, they are quite small, and normally I wouldn't be too concerned with them.  However, if the errors persist, they can really slow down your simulation time.  Sometimes adding several hours to the overall time, in my experience.  So while the errors are small, there is a need to get rid of them, at least the ones that persist for many timesteps.  

A common cause of nuisance cell errors is what I call "wedge depressions".  In the following figure, notice the wedge of water that sits below a well defined ridge line.  The red arrow points to it.  


As you can see by the blue hydraulic connectivity lines that there is hydraulic connectivity between Cell 1 and Cell 2.  But water fills up cells from the lowest spot, and in Cell 2, this is below the ridge.  So you get a narrow wedge of water (wedge depression) that builds up causing some local fragmentation and a resulting error.  Notice the water just abruptly stops at the cell face between Cell 1 and Cell 2.  Wedge depression doesn't always cause an error (by error, I mean RAS cannot converge on a solution within the error tolerance in 20 iteration tries).  But it did in Cell 2.  Notice Cell 4 has the same wedge depression, but it was not producing errors in this simulation (ahhh, the mysteries of HEC-RAS!).  

Fortunately, the fix for this is easy.  You draw a breakline along the ridge line so that a cell face resides on the ridge line itself.  This removes the low spot (and thus the wedge depression) in Cell 2.  the next figure shows the placement of the breakline (but before enforcement).  In this case, to preserve the spacing of the cells on the north side of the line, I specified a cell center spacing of 55 feet on the breakline (actually, I started with 40 feet, then 50 feet, but these produced the dreaded "red dots".  55 feet worked.)


After a bit more tweaking of the breakline alignment, here is the result with the breakline enforced and the wedge depression eliminated.  Notice without the wedge depression, flow is able to move more naturally towards the upper left from what used to be Cell 1.  Oh yeah...and no more nuisance cell errors!  


Yes...there's still some more fragmentation that could be addressed, but this is early on in the simulation and my objective is to ultimately present the max ws maps.  So my concern at this point in the simulation is to have decent results with fast simulation times.  I'm not concerned with little bits of fragmentation that don't throw errors.