RAMMS Debris Flow Modelling Manual

User Manual v1.5Debris Flow

A numerical model for debris flows in research and practice

rapid mass movements simulation

RAMMS

WSL Institut für Schnee- und Lawinenforschung SLFWSL Institut pour l‘étude de la neige et des avalanches SLFWSL Instituto per lo studio della neve e delle valange SLFWSL Institute for Snow and Avalanche Research SLF

faketext

Title picture: Debris flow at Illgraben, Ueli Schälchli, 1993

Contributors (alphabetical order)

Perry BarteltYves Buehler

Marc ChristenYolanda Deubelbeiss

Christoph GrafBrian McArdell

Maren SalzMaike Schneider

Manuscript updateMarch 11, 2013

Contents

1 Introduction 1

2 Learning by doing 3

3 Setup and first start 53.1 System requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53.2 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

3.2.1 Installation procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . 63.3 Licensing methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123.4 First start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

3.4.1 Personal license request file . . . . . . . . . . . . . . . . . . . . . . . . 133.4.2 Get the personal license key . . . . . . . . . . . . . . . . . . . . . . . . 14

3.5 Update . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143.6 Preferences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

4 Working with RAMMS 194.1 Preparations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

4.1.1 Project and Scenarios . . . . . . . . . . . . . . . . . . . . . . . . . . . 194.2 Model input data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

4.2.1 Topographic data – Digital Elevation Model (DEM) . . . . . . . . . . . 204.2.2 Release information . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214.2.3 Friction information . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224.2.4 Calculation parameters . . . . . . . . . . . . . . . . . . . . . . . . . . 23

4.3 Creating a project with the Project Wizard . . . . . . . . . . . . . . . . . . . . 244.4 Working with the interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

4.4.1 Moving, resizing, rotating, viewing . . . . . . . . . . . . . . . . . . . . 284.4.2 Colorbar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 314.4.3 Changing maps and remote sensing imagery . . . . . . . . . . . . . . . 324.4.4 How to save input files and program settings . . . . . . . . . . . . . . 334.4.5 How to open input and output files . . . . . . . . . . . . . . . . . . . . 344.4.6 About RAMMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

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Contents

4.5 Running a calculation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 364.5.1 Release area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 364.5.2 Input hydrograph . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 404.5.3 Calculation Domain . . . . . . . . . . . . . . . . . . . . . . . . . . . . 444.5.4 Running a calculation . . . . . . . . . . . . . . . . . . . . . . . . . . . 454.5.5 Project information . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

4.6 Visualization and analysis of the results . . . . . . . . . . . . . . . . . . . . . 534.6.1 Visualize different parameters . . . . . . . . . . . . . . . . . . . . . . . 534.6.2 Line profile and time plot . . . . . . . . . . . . . . . . . . . . . . . . . 534.6.3 Creating an image or a GIF animation . . . . . . . . . . . . . . . . . . 604.6.4 Stopping mechanism . . . . . . . . . . . . . . . . . . . . . . . . . . . 614.6.5 Numerical instabilities . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

4.7 Adding structures or deposition to DEM . . . . . . . . . . . . . . . . . . . . . 664.7.1 Creating a dam . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 674.7.2 Creating a new DEM with deposited debris material . . . . . . . . . . . 70

5 Applications 715.1 Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 715.2 Input hydrograph in comparison with block release . . . . . . . . . . . . . . . 76

5.2.1 Comparison between a block release and an input hydrograph . . . . . 765.2.2 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 775.2.3 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

5.3 Example using block release simulations . . . . . . . . . . . . . . . . . . . . . 795.3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 795.3.2 Field setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 795.3.3 Modeling debris flows at Illgraben . . . . . . . . . . . . . . . . . . . . 805.3.4 Problems and difficulties . . . . . . . . . . . . . . . . . . . . . . . . . 815.3.5 Summary of input parameters for simulations at Illgraben . . . . . . . . 83

5.4 Active–passive earth-pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . 845.5 Calculation of impact pressures . . . . . . . . . . . . . . . . . . . . . . . . . . 86

6 Program overview 876.1 The Graphical User Interface (GUI) . . . . . . . . . . . . . . . . . . . . . . . . 87

6.1.1 The menu bar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 886.1.2 Horizontal toolbar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 956.1.3 Vertical toolbar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 976.1.4 Main window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 986.1.5 Dump-step slider . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 986.1.6 Left status bar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

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Contents

6.1.7 Right status bar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 986.1.8 Colorbar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 996.1.9 Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

6.2 File management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1026.2.1 Software RAMMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1026.2.2 Organizing your data . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

7 References and further reading 1057.1 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1057.2 Publications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

List of Figures i

List of Exercises v

Index vii

WSL Institute for Snow and Avalanche Research SLF iii

1 Introduction

In the field of natural hazards there is an increasing demand for process models that helpunderstand the dynamics of geophysical mass movements – from initiation to release. Thesemovements include snow avalanches, debris flows, hillslope debris flows, landslides, mud flowsand even rockfalls and rock avalanches. Models allow engineers to predict the speed andrunout of these hazardous movements in complex terrain. Such models are especially help-ful when proposing mitigation measures where knowledge of the inundated area is of criticalimportance. Hazard mapping, the primary application in Switzerland and other mountain-ous countries, requires models that allow engineers to test different hazard scenarios. Whilewell-tested empirical methods are available to determine runout distances, velocities and flowheights, numerical models now provide cell information on flow height and flow velovity andallow practitioners to predict flow paths in general terrain as well as to model entrainmentprocesses or the breaking effect of forests. Better mitigation strategies can result.

RAMMS (RApid Mass Movements Simulation) is a state-of-the-art numerical simulation modelto calculate the motion of geophysical mass movements (snow avalanches, debris flows, rock-falls) from initiation to runout in three-dimensional terrain. It was designed to be used in prac-tice by hazard engineers who need solutions to real, everyday problems. It is coupled with auser-friendly visualization tool that allows users to easily access, display and analyze simulationresults. New constitutive models have been developed and implemented in RAMMS, thanks tocalibration and verification at full scale tests at sites such as Illgraben (debris flow), Veltheim(hillslope, shallow landslides, mitigation measures), Vallée de la Sionne (snow avalanches) andSt. Léonard (rockfall, mitigation measures). These models allow the application of RAMMSto solve both large, extreme avalanche events as well as smaller mass movements such ashillslope debris flows and shallow landslides.

RAMMS was developed by the RAMMS program team at the WSL Institute for Snow andAvalanche Research SLF. This manual describes the features of the RAMMS program - allow-ing beginners to get started quickly as well as serving as a reference to expert users.

On the RAMMS web page http://ramms.slf.ch you find useful features such as a moderateddiscussion forum, frequently asked questions (FAQ) or recent software updates. Please visitthis web page frequently to stay up to date!

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http://ramms.slf.ch

CHAPTER 1. INTRODUCTION

DISCLAIMER

RAMMS is intended to be used as a tool to support experienced users. The interpretationof the simulation results has to be done by an expert in debris flow characterization whois familiar with the local as well as with the topographic and meteorological situationof the investigation area. In no event shall WSL/SLF be liable for any damage or lostprofits arising, directly or indirectly, from the use of RAMMS. Swiss law applies. Courtof jurisdiction is Davos. If you encounter problems, please contact [email protected].

2 RAMMS User Manual

2 Learning by doing

This manual provides an overview of RAMMS. Exercises exemplify different steps in settingup and running a RAMMS simulation especially in Chapter 4: Working with RAMMS.However, to get the most from the manual, we suggest reading it through while simultaneouslyhaving the RAMMS program open, learning by doing. We assume RAMMS users to havea basic level of familiarity with windows-based programs, commands and general computerterminology. We do not describe the basics of windows management (such as resizing orminimizing). RAMMS windows, click options and input masks are similar to other windows-based programs and can be used, closed, reduced or resized in the same way.

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3 Setup and first start

3.1 System requirements

We recommend the following minimum system requirements for running RAMMS:

• Operating System: Windows XP (32-bit) and Windows 7 (64-bit)(or Windows-Virtual Machine VM)

• RAM (memory): 2 GB or more GB

• CPU: Intel Pentium 1 GHz (dual core recommended)

• Harddisk: ca. 200 MB

3.2 Installation

Please download the RAMMS setup file ramms_dbf_user_setup_64.exe for Windows 7 andramms_dbf_user_setup.exe for Windows XP from

http://ramms.slf.ch/ramms/downloads/ramms_dbf_user_setup_64.zip, respectivelyhttp://ramms.slf.ch/ramms/downloads/ramms_dbf_user_setup.zip

Please do the following steps before you begin to install RAMMS:

• Click on the path given above or copy the path to any browser. A window pops up and theautomatic download of the file ramms_dbf_user_setup_64.exe or ramms_dbf_user_setup.exestarts after clicking yes.

• You must have Administrator privileges on the target machine. If you do not have suchprivileges, the installer cannot modify the system configuration of the machine and theinstallation will fail. Note that you do not need Administrator privileges to run RAMMSafterwards.

• Read first, install afterwards! Please read the whole installation process once, before youbegin the installation!

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http://ramms.slf.ch/ramms/downloads/ramms_dbf_user_setup_64.zip

http://ramms.slf.ch/ramms/downloads/ramms_dbf_user_setup.zip

CHAPTER 3. SETUP AND FIRST START

3.2.1 Installation procedure

Step 1: WelcomeStart the file ramms1.5.01_dbf_setup_64.exe. The welcome dialog introduces you to theEnglish setup program and will guide you through the installation process. Click Next tocontinue.

Figure 3.1: Installation - welcome dialog window.

Step 2: ReadmeShort introduction to RAMMS. Click Next to continue.

Figure 3.2: Installation - readme dialog window.

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3.2. INSTALLATION

Step 3: Accepting the license agreementRead the license agreement carefully and accept it by activating the check box in the lowerleft corner. If you do not accept the license agreement, you are not able to proceed with theinstallation. After accepting the license agreement, click Next to continue the installation.

Figure 3.3: Installation - license agreement dialog window.

Step 4: Select destination directoryChoose your destination directory. Simultaneously this dialog shows the amount of spaceavailable on your hard disk and required for the installation. Beware: Do NOT use a blank orspecial characters within your installation directory path name (e.g. C:\program files\RAMMSis not allowed, use C:\Programs\RAMMS or C:\Programme\RAMMS instead).Click Next to start the installation process.

Figure 3.4: Installation - destination directory dialog window.

WSL Institute for Snow and Avalanche Research SLF 7


Step 5: Installing the filesRAMMS is copying the files to the destination location and showing the installation progress.

Figure 3.5: Installation - installing files dialog window.

Step 6: Finished installing the filesRAMMS finished copying the files. Click Next to finish the installation process.

Figure 3.6: Installation - finished installing files dialog window.

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3.2. INSTALLATION

Step 7: RAMMS installation finished!RAMMS successfully finished the installation. Click Finish.

Figure 3.7: Installation - finished installation dialog window.

Step 8: Welcome to IDL Visual Studio Merge ModulesTo ensure all important system libraries are installed on your target machine follow the instruc-tions below:

The welcome dialog introduces you to the English setup program and will guide you throughthe installation process of the IDL Visual Studio Merge Modules. Click Next to continue.

Figure 3.8: IDL Visual Studio Merge Modules - welcome dialog window.



Step 9: Ready to install the programClick Next to continue.

Figure 3.9: IDL Visual Studio Merge Modules - ready to install the program.

Step 10: Installing IDL Visual Studio Merge ModulesThe wizard is installing the files. Please wait until it is finished.

Figure 3.10: IDL Visual Studio Merge Modules - installing...

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3.2. INSTALLATION

Step 11: InstallShield Wizard CompletedThe wizard completed the installation. Click Finish.

Figure 3.11: Installation - destination directory dialog window.

After having successfully installed RAMMS and the necessary files on your personal computer,you will notice the RAMMS icon on your desktop (for all users):

Figure 3.12: RAMMS icon.

Additionally, a new application folder is created in Start → Programs (for all users):

• RAMMS → Run RAMMS

• RAMMS → Uninstall RAMMS

Figure 3.13: RAMMS program group.



3.3 Licensing methods

Access to RAMMS is controlled by a personal use license. Personal use licenses are time limitedlicenses tied to a single personal computer. This method of licensing requires a machine’sunique host ID to be incorporated into a license request file. After the license request fileis sent to WSL/SLF, you will receive a license key. Entering the license key on a personalcomputer enables full RAMMS functionality for the specific personal computer. For moreinformation please visit http://ramms.slf.ch.

3.4 First start

Double-click the icon or use Start→ Programs→ RAMMS→ Run RAMMS to start RAMMSfor the first time. Whenever you start RAMMS, the splash screen below will pop up:

Figure 3.14: RAMMS start window.

Click on the image. It will disappear and RAMMS will start up. The following dialog windowappears (Fig. 3.15 RAMMS - Licensing):

Figure 3.15: RAMMS licensing window.


http://ramms.slf.ch

3.4. FIRST START

3.4.1 Personal license request file

Click the button to create your personal license request file. In Fig. 3.16 enter your fullname and the name of your company.

Figure 3.16: Enter user name and company name.

In the next dialog window, choose the destination directory of your personal license requestfile and save it to your target machine. Your personal license request file should look similarto Fig. 3.17.

Figure 3.17: Personal license request file RAMMS_request_Muster Test.txt



3.4.2 Get the personal license key

You find an order form on the RAMMS web page Order Form or Demo Order Form athttp://ramms.slf.ch/. Fill in all your personal information, choose license period, licensetyp and number of licenses you wish to order, attach your personal license request file(s),accept the license agreement and click Submit Order.

An order confirmation email is sent to your email address. We then process your order andsend you an invoice. As soon as we received your payment, we will send you your personallicense key. Your personal license key is named similar to RAMMS_license_Muster Test.txt.Open the file in a text-editor. It should look similar to Fig. 3.18.

Figure 3.18: Personal license key file RAMMS_license_Muster Test.txt

Now, restart RAMMS (as explained before). Again, the pop-up window (Fig. 3.14) andthen the dialog window (Fig. 3.15) appears (RAMMS - Licensing). Copy the license key (inthis example: akck-3ijh-3jtl-2h5h-g340) and paste it at license key (see Figure 3.15). Noticethat there might be a prefix DEBRISFLOW. This prefix is part of the license key and hasto be inserted as well! If RAMMS accepts your installation key, you successfully finished theinstallation.

3.5 Update

When you start RAMMS it will automatically check for updates on the internet. This couldlead to an error message, if your firewall blocks the executable idlrt.exe (this file starts theIDL-Virtual Machine you need to run RAMMS). Please unblock this file for your firewall.You can also disable the AutoWebUpdate-function by unchecking Help → Advanced... →AutoWebUpdate. The WebUpdate-function can still be done manually under Help→ Update...→ Web Update or go to Help → Update... → get manually and download the file to yourlocal folder.


http://ramms.slf.ch/

3.6. PREFERENCES

3.6 Preferences

Before starting to work with RAMMS, be sure to set your RAMMS preferences and placethe necessary DEM (Digital Elevation Model) files as well as the MAPS and georeferencedIMAGERY you wish to use in the appropriate folders defined in the preferences, see Figs. 3.19and 3.20.Use Track → Preferences to open the RAMMS preferences window or click the button .For resetting the general preferences use Help → Advanced... → Reset General Preferences.

Figure 3.19: General tab of RAMMS prefer-ences.

Figure 3.20: Debris flow tab of RAMMS prefer-ences.

General tab

Setting Purpose

Working directorySet your working directory. VERY IMPORTANT: DoNOT use BLANKS in the working directory path!

Map directorySet the folder where you place your georeferenced dig-ital maps (consists of a TIFF-file and a correspondingtfw-file (world-file).

Image directorySet the folder where you place your digital georefer-enced orthophotos (aerial picture, consists of a TIFF-file and a corresponding tfw-file (world-file).

DEM directorySet the folder where you place the Digital ElevationModels respectively the Digitial Terrain Models (for-mat: ASCII grid, see 4.2.1 on page 20)



Debris flow tab

Setting Purpose

Read timestepsChoose between reading ALL or only 1 timestep.Default is reading ALL timesteps.

Nr of colorbar colors Set default nr of colorbar colors.GIF-Animation interval (s) Set interval for GIF-Animation images.

Background colorSet background color (greyscale between 0:blackand 255:white).

Animation delay (s)Set animation delay to decelerate the animationspeed.


3.6. PREFERENCES

The following exercise "Working directory" shows how to choose a new working directory. Allfurther settings can be changed in a similar manner. The settings are saved, until they arechanged again manually.

Exercise 3.6.a: Working directory

Choosing the right working directory is very useful and saves a lot of time, searching forfiles and folders.

VERY IMPORTANT: Do NOT use blanks or special characters in the path names!

◦ Click (or use Track → Preferences) to open the RAMMS preferences window.◦ Click into the field Working directory, then the appearing arrow and Edit...

A window pops up where you can choose your new working directory. Click OK inboth windows.

Figure 3.21: RAMMS preferences. Figure 3.22: Browse for the correct folder.


4 Working with RAMMS

All topographic base maps and aerial images shown in this manual are reproduced c©2012swisstopo (JD100007).

4.1 PreparationsTo successfully start a new RAMMS project, a few important preparations are necessary.Topographic input data (ascii format), project boundary coordinates and georeferenced mapsor remote sensing imagery should be prepared in advance (.tif format and .tfw file, maps andimagery are not mandatory, but nice to have). Georeferenced datasets have to be in a Cartesiancoordinate system (e.g. Swiss CH1903 LV03), polar coordinate systems (e.g. WGS84 LongLat) are not supported. Fore more information about specific national coordinate systemsplease contact the national topographic agency in your country.

4.1.1 Project and ScenariosA project is defined for a region of interest. Within a project, one or more scenarios canbe specified and analyzed. For every scenario, a calculation can be executed. A projectconsists therefore of different scenarios (input files) with different input parameters. The basictopographic input data are the same for every scenario (Fig. 4.1). If you want to changethe topographic input data (e.g. change the input DEM resolution or the project boundarycoordinates) you have to create a new project. Other input parameters friction parameters(such as release areas, calculation domain, calculation grid resolution, end time or time step)can be changed for every scenario.

Figure 4.1: The same project extent (area ofinterest) can be used to calculate differentscenarios with different input parameters.

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CHAPTER 4. WORKING WITH RAMMS

4.2 Model input data

There are different kinds of data to be provided to successfully perform a calculation withRAMMS. Topographic data, definition of release area or hydrograph and release volume aswell as information about friction parameters are mandatory.

4.2.1 Topographic data – Digital Elevation Model (DEM)

The topographic data is the most important input requirement. The simulation results dependstrongly on the resolution and accuracy of the topographic input data. Before you start asimulation make sure all important terrain features are representented in the input DEM.RAMMS is able to process the following topographic data:

• ESRI ASCII grid (Fig. 4.2)• ASCII X,Y,Z single space data (Fig. 4.3)

These data types are also available e.g. from www.swisstopo.ch. Because RAMMS needs thetopographic data as an ESRI ASCII grid, ASCII X,Y,Z data can be converted within RAMMSinto an ESRI ASCII grid. At this stage no other data types are processable. The user musttherefore prepare the topographic data according to this limitation. The header of an ESRIASCII grid must contain the information shown in Fig. 4.2

Figure 4.2: Example ESRI ASCII grid. Figure 4.3: Example ASCII X,Y,Z single spacedata.

Conversion into ESRI ASCII gridAn ESRI ASCII grid can be created in ArcGIS with the function ArcToolbox→ConversionTools→From Raster→Raster to ASCII.

It is also possible to import ASCII X,Y,Z single space data and convert the data into an ESRIASCII grid (using Track→New...→Convert XYZ to ASCII grid).


www.swisstopo.ch

4.2. MODEL INPUT DATA

4.2.2 Release information

In RAMMS::Debris Flow there are two options to define the starting conditions (release infor-mation) of a simulation:

• Release area (or block release)• Input hydrograph (or simply hydrograph)

The starting conditions of a simulation can be selected depending on the type of debris flow youwant to model. Generally, it is useful to distinguish between unchannelized and channelizeddebris flows. Here we use the term unchannelized debris flow for hillslope debris flows orshallow landslides, channelized debris flows develope in regions where torrents limit the flowpaths and the debris material mainly follows the torrent channel.

For small unchannelized debris flows it is useful to use a release area with a given initial height,which will be released as a block (block release), while for a channelized debris flow it maybe more appropriate to use an input hydrograph. The later requires knowledge of the amountof material that might flow past a certain location in the channel. Chapter 5 includes severalexamples for both types of starting conditions.

The definition of release areas and release heights (block release) have a strong impact on thesimulation results. The same applies for simulations with a hydrograph, where the results aresensitive to the discharge hydrograph. Therefore, we recommend to use reference informationsuch as photography, GPS measurements or field maps to draw release areas and to usemeasured or well-estimated inflow data to define discharge hydrographs. This should be doneby people with experience concerning the topographic and historical flow situation of theinvestigation area.

More details on how to create release areas are given in section 4.5.1, page 36pp. Details onhow to use an input hydrograph are given in section 4.5.2, page 40pp.



4.2.3 Friction information

RAMMS employs a Voellmy-fluid friction model, which is based on the Voellmy-Salm approach(we refere to Salm et al. 1990 [13] and Salm 1993 [14]).

The choice of the friction parameters requires careful calibration (section 5.1) of the modelby using reference information such as field data, photographies of runout zones, estimationsor measurements of flow velocities and flow heights as well as estimations of the materialcomposition. This should be done by an persons with expertise in debris flow characterization.

Physical friction model

The physical model of RAMMS::Debris Flow uses the Voellmy friction law. This model dividesthe frictional resistance into two parts: a dry-Coulomb type friction (coefficient µ) that scaleswith the normal stress and a velocity-squared drag or viscous-turbulent friction (coefficient ξ).The frictional resistance S (Pa) is then

S = µρHgcos(φ) + ρgU2

ξ, (4.1)

where ρ is the density, g the gravitational acceleration, φ the slope angle, H the flow height andU the flow velocity. The normal stress on the running surface, ρHgcos(φ), can be summarizedin a single parameter N . The Voellmy model accounts for the resistance of the solid phase (µ issometimes expressed as the tangent of the internal shear angle) and a viscous or turbulent fluidphase (ξ was introduced by Voellmy using hydrodynamic arguments). The friction coefficientsare responsible for the behavior of the flow. µ dominates when the flow is close to stopping,ξ dominates when the flow is running quickly.

Throughout one simulation the friction coefficients of a calculation domain are constant. How-ever you have the possibility to add up to two polygons within the calculation domain withdifferent friction parameters (see exercise ”How to ru a calculation” on page 45pp.)

The Voellmy friction model has found wide application in the simulation of mass movements,especially snow avalanches. For modeling snow avalanches the Voellmy model has been in usein Switzerland for many years and a set of standard parameters is available.


4.2. MODEL INPUT DATA

Calibration of the friction parameters µ and ξ

Although the data base for well documented debris flow events is smaller than the one for snowavalanches, we have a good idea of the friction parameters which have to be used. The majordifficulty in case of debris flow simulation is the large variety of debris flow compositions, whichhas a strong influence on the choice of the friction parameters. RAMMS::Debris Flow uses asingle-phase model, so we cannot distinguish between fluid and solid phases and the material ismodeled as a bulk flow. Therefore, the friction parameters should be varied to match observedflow properties (for calibrating the model) or expected flow properties (if variation is expectedas part of a hazard scenario).

It is common that different events in the same torrent show strong differences in composition.This fact makes the calibration of the friction parameters much more difficult and even requiresa calibration for different events. Therefore, we strongly recommend careful calibration of thefriction parameters by persons with expertise in debris flow characterization.

The calibration procedure of the Voellmy model is explained with an example in section 5.1.

4.2.4 Calculation parameters

Calculation parameters, such as output name, simulation grid resolution, simulation (end)time, time step etc. can be changed interactively in the RAMMS Run Simulation Widget.



4.3 Creating a project with the Project Wizard

A new project is created with the RAMMS Project Wizard shown in the exercise below. Thewizard consists of four steps:

Exercise 4.3.a: How to create a new project.

◦ Click or Track → New → Project wizard to open the RAMMS ProjectWizard.

◦ The following window pops up:

Figure 4.4: RAMMS Project Wizard: Step 1 of 4.


4.3. CREATING A PROJECT WITH THE PROJECT WIZARD

Continuation of exercise 4.3.a: How to create a new project.

Step 1:◦ Enter a project name.◦ Add some project details.◦ The project location suggested is the current working directory. To change the

location click into the location field. A second window appears and you can browsefor a different folder (see figure below)VERY IMPORTANT: Do NOT use blanks or special characters in the pathnames!).

◦ Click Next.

Figure 4.5: Step 1 of the RAMMSproject wizard: Project information.

Figure 4.6: Window to browse for anew project location.

Step 2:◦ Locate your DEM-file in the folder

set in the RAMMS preferences.Click into the corresponding fieldsto browse for the appropriate files.

◦ The use of FOREST-files is notsupportet in this version.

◦ Click Next.

Figure 4.7: Step 2 of the RAMMSproject wizard: GIS information.



Continuation of exercise 4.3.a: How to create a new project.

Step 3:◦ Enter the X- and Y-coordinates of the lower left and upper right corner of your

project area, using the Swiss Coordinate System CH1903 LV03 (or another cartesiancoordinate system), as it is shown below for the Vallée de la Sionne area.

Figure 4.8: Project coordinates: Lower left andupper right corner of project area.

Figure 4.9: Step 3 of the RAMMSproject wizard: Project bound-ary coordinates.

Step 4:◦ Check the project summary if a DEM-file

was found.◦ If several matching tif files exist, RAMMS

shows a list with all these files.◦ To make changes click Previous, to create

the project click Create Project.

Figure 4.10: Step 4 of the RAMMSproject wizard: Project summary.

Project creation:◦ The creation process can take a while. Different status bars will pop up and show

the progress of the project creation process.


4.3. CREATING A PROJECT WITH THE PROJECT WIZARD

The following files will be created in the project folder:

Figure 4.11: Created project files.

File / Folder Purposedoc (folder) Folder containing input and ouput Log fileslogfiles (folder) Project creation and calculation log filesdhm.asc ASCII grid with altitude valuesdhm.sav Height information used in RAMMS_.db2 Input file_.dom Calculation domain ASCII file_dom.shp Calculation domain shapefile_dom.shx Calculation domain shapefile_dom.dbf Calculation domain shapefile_.xyz Topographic data used in RAMMS



4.4 Working with the interface

Once the project is created, there are several useful tools which can be helpful when workingwith RAMMS. They are explained in the excercises below.

4.4.1 Moving, resizing, rotating, viewing

Exercise 4.4.a: Moving and resizing the model

a) Terrain model has a dimension of 100% or smaller:

◦ By clicking on the "arrow" , the model can be moved and resized.

Figure 4.12: "Active" project with lines and corners for resizing

◦ To move the model without changing size or aspect ratio, move to the model andcheck if the cursor turns to . Then click and hold the left mouse button anddrag the model to the desired position.

◦ To resize the model without changing the aspect ratio, use the mouse wheel to zoomin our out. Alternatively, you can resize the model by changing the percentage valuein the horizontal toolbar .

b) Terrain model has a dimension > 100%:◦ All steps explained above are still possible.◦ In addition to this, the white hand right next to the rotation button becomes active

as well. After clicking on this so-called view pan button , it is also possibleto move the model.


4.4. WORKING WITH THE INTERFACE

Exercise 4.4.b: Rotating the model

◦ After activating the rotation button , the model can be rotated alongthe rotation axis, by moving the cursor directly on one of the axis until the cursorchanges from to . Otherwise a freehand rotation in any direction is possible.

Figure 4.13: "Active" project with rotation axes.



Exercise 4.4.c: How to switch between 2D and 3D mode

◦ Click to switch from 3D to 2D view. This button then changes to and byclicking again, you will return to 3D view.

Figure 4.14: 3D view of example model. Figure 4.15: 2D view of example model.

In 2D-mode you have all possibilities that you know from 3D-mode. It works for inputfiles as well as for simulations. For the following functions of RAMMS it is necessary toswitch from 3D to 2D view:

INPUT OUTPUT

◦ Draw new release area ◦ Draw line profile

◦ Release area information

◦ Crop release area

◦ Draw new domain



4.4.2 ColorbarAs soon as a parameter is shown in the project, the colorbar appears on the right side of themain window. It can be turned on and off by clicking on .As soon as a parameter is shown in the project, the colorbar appears on the right side of themain window. It can be turned on and off by clicking on .The colorbar can be moved anywhere in the sreen (and can get lost). Use Project→GetColorbar to find a lost colorbar.

Exercise 4.4.d: Editing the colorbar

Changing the minimum and maximum values of the colorbar as well as changing thenumber of colors used is done in the panel Debris Flow under Display.

◦ Simply type a new value into the respective fieldand hit the return key on the keyboard. Thedisplay will be refreshed.

◦ To view the underlying topography or image,you can change the transparency.

◦ ATTENTION:Values < x.xxx are not displayed!The cut off depends on the min and max valuesas well as on the number of colors. Make surethat you have the range of values you want todisplay!

Figure 4.16: The displaytab.

◦ Open the editing window by either choosingEdit→colorbar properties or clicking in thevertical toolbar.

◦ To change the colorbar properties simply clickinto the field you want to change, then click OK.

Figure 4.17: The colorbarproperties window.

Under Edit→Colorbar White Color the text-color of the colorbar can be changed towhite. This can be useful when changing the background color of your project to whiteTrack→Preferences→Debris flow tab→Background color (see debris flow tab p.16).



4.4.3 Changing maps and remote sensing imagery

It is possible to change the map or imagery of a project anytime. Take into account, that thecorresponding TFW-file (world-file) has to be in the same folder as the actual map (*.tif). Ifthis is not the case, the map will not be found!

To check which map and imagery are currently loaded in the project, open the project input(or output) log (Project→Input Log File). Next to map image and ortho image you will findthe location and name of the loaded map and imagery, respectively.

Exercise 4.4.e: How to add or change maps.

a) Add or change a map:

◦ Go to Extras→Add/Change Map or clickIf more than one map is found, the following window pops up, listing the mapsfound:

Figure 4.18: Window to choose mapimage.

Information on the image dimensions (x-Dim and y-Dim, pixel) and size (in MB)are provided and might be a selection criterion.

◦ Select the map you wish to add and click Load selected map.

b) Map not found:◦ If the question "No map found, continue search?" appears, you either don’t have

an appropriate map, the map-folder directory is set wrong or the map is saved in adifferent folder. In the latter case click Yes and choose the correct folder.

◦ Click No to cancel search or click Yes to continue search.◦ A window pops up to browse for the correct map location and file.

Exercise 4.4.f: How to add or change remote sensing imagery.

◦ Go to Extras→Add/Change Image or click .I See exercise "How to add and change maps" on page 32 above.



4.4.4 How to save input files and program settings

Once a project is created, it is saved under the name and location you entered during step 1of the RAMMS::Debris Flow Project Wizard (see figure 4.5 on page 25). The created inputfile has the ending *.db2.

The second situation in which the input file is saved automatically, is when a calculation isstarted. The saved input file has the same name as the created output file.

Exercise 4.4.g: How to save input files and program settings manually.

a) Input file:◦ In case you want to save the input file manually before running a calculation, go

on Track→Save. This is helpful, when a release area was loaded but you wish toclose the project before doing the calculation.

◦ If you wish to save a copy of your file under a new name, go on Track → SaveCopy As or click .

◦ A window pops up to choose an old file which should be overwritten or to type ina new name, then click Save.

◦ Continue working on the original file, not the just saved one!

b) Program settings:◦ If you have moved and/or rotated your project for a better view, you can save this

position by going on Extras→Save Active Position.◦ You can now get back to this position anytime by choosing Extras→Reload Po-

sition.



4.4.5 How to open input and output files

Exercise 4.4.h: How to open an input file.

◦ Close any active project file.

◦ Go to Track→Open...→Input File or click .◦ A window opens to browse for a debris flow input file (*.db2).◦ Click Open after file name was selected.◦ The project will be opened.

Exercise 4.4.i: How to open an output file/debris flow simulation.

◦ Close any active project file.

◦ Go to Track→Open...→Debris Flow Simulation or click .◦ A window opens to browse for a debris flow simulation file (*.out.gz)◦ Click OK.◦ The simulation will be opened.

Exercise 4.4.j: How to load an optional shapefile.

◦ To load a shapefile, click .◦ A window opens to browse for a shapefile (*.shp).◦ Click Open after file was selected.



4.4.6 About RAMMS

Some information about the RAMMS installation on your computer is found here:Help→About RAMMS....

Figure 4.19: About RAMMS...



4.5 Running a calculation

To run a calculation or a specific scenario within a newly created project (creating a projectsee section 4.3) it is necessary to define a release area or an input hydrograph and a calculationdomain. The definition of a smaller calculation domain is especially usefull to keep the numberof calculation points as small as possible, that is, it is best to test what the flow path of asimlation will be to limit the calculation domain to this extent. The exercises below show youhow to create a release area, how to use an input hydrograph and how to create a calculationdomain. A simulation also requires a set of friction parameters. Details on the friction modelused in RAMMS::Debris Flow are given in section 4.2.3.

4.5.1 Release area

There are different possibilities to include a release area into the project. The following tablegives an overview of the possibilities RAMMS offers. For further explanations see the exercisesbelow.

Create a new release areaIf there is no release area available for your project, oryou wish to create a new one, switch to 2D mode andclick .

Load an existing release area Load an existing release area with Input → Release area→ Load existing release area.

Import a shapefile and con-vert it to a release area

Draw a release area using a GIS-tool and save it as a poly-gon shapefile (.shp). Then convert the shapefile usingGIS → Convert Polygon Shapefile → Polygon Shapefileto RAMMS Release Shapefile.


4.5. RUNNING A CALCULATION

Exercise 4.5.a: How to create a new release area.

◦ Switch to 2D mode by clicking .◦ Activate the project by clicking on it once.

◦ Click .◦ Click into the project where you want to start drawing the outline of the release

polygon.◦ Continue drawing the release polygon by moving the cursor and clicking the left

mouse button.◦ To end the release polygon, click the right mouse button. The polygon will be

closed automatically.

Figure 4.20: Project with emerging release area.

Before the release area is created, you have to answer a few questions:

◦ Add more release areas?You can either answer with Yes and create a second release polygon as explainedabove or answer with No and continue with the next step.

◦ Choose a new release filename:Enter a new name for the release area. The ending *rep.shp is added automatically.

The release area will now be created and opened directly, as well as the colorbar.



Exercise 4.5.b: How to load an existing release area.

◦ Choose Input→Release area...→Load existing release area.◦ Select release file (*rep.shp) and click open.→ The release area appears in the project as well as the colorbar for the variablerelease height (m)

Once a release area is created or loaded, you have to specify the release height. Switch to 2Dmode, choose Input→Release area...→Details/Edit release area or click the button andchoose the release area polygon by selecting it with the left mouse button. The appearingwindow yields information about release area, mean slope angle, mean altitude and estimatedrelease volume. And, most importantly, the release height can be entered, see exercise below.

Additional release information is found in the panel Debris Flow, tab Volumes (Fig. 4.21)below.

Figure 4.21: Release area and volume information.



Exercise 4.5.c: Specify release height and view release information

◦ Switch into 2D mode by clicking .

◦ Click on the View/Edit release area button (in the horizontal toolbar or inthe volumes tab in the panel) or choose Input→Release area...→Details/Editrelease area.

◦ Then click on the release area you want to get information on. A red polygon isdrawn around the selected release area. The following window appears:

Figure 4.22: Release area information window.

◦ To change the release height enter a new value (the resulting release volume isdirectly adjusted. Click OK if you want to keep the changes, Cancel otherwise.



4.5.2 Input hydrograph

To simulate channelized debris flows it is advantageous to use an input hydrograph. However,this requires knowledge of the amount of material (discharge) that flows past at a givenlocation. For a RAMMS simulation with a hydrograph you have two options. Either you knowthe discharge at different times at a given location, e.g. estimated by measured flow heightsand corresponding channel cross sections or you use the estimated total volume in combinationwith empirical relationships between total volume and maximum discharge ( e.g. Rickenmannet al. 1999 [11]).

Field measurement of debris flow properties is beyond the scope of this handbook, howeverif debris flow activity in a catchment is frequent, it may be possible to obtain additionalinformation for calibrating RAMMS by installing a monitoring station. Many debris flows,when the monitoring data are simplified, have a relatively simple triangular wave-like shape(Fig. 4.23). Assuming a well-estimated total volume (e.g. field data), maximum debris flowdischarge (Q) and corresponding time (t1), as well as the end time (t2) can be calculated. Wecall this a three-point hydrograph calculation.

0

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0 200 400 600 800 1000 1200 1400

Dis

ch

arg

e [m

3/s

]

Time [s]

Four-point hydrograph

Three-point-hydrograph

Q1, t1

Q2, t2 Q0, t0

Maximum discharge

Total volume

Figure 4.23: Three-point hydrograph with total volume of debris flow.



In nature, discharge hydrographs are generally better described by four points (Figs. 4.24and 4.25). However, a three-point hydrograph results in slightly larger flow heights and flowvelocities after the maximum discharge. If the detailed discharge hydrograph is not known itis useful to choose a three-point hydrograph. In critical applications we encourage users toevaluate the sensitivity of the model results to the shape of the input hydrograph, e.g. whenpreparing different scenarios as a basis for hazard maps.

0

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Illgraben August 2, 2005

Figure 4.24: Four-point hydrograph for discharge values of an event, August 2, 2005, at Illgraben,Valais, Switzerland.

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ch

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Three-point-hydrograph

Figure 4.25: Comparison of a three-point with a four-point hydrograph for the given discharge datawith the same total volume.



Input data for a discharge hydrograph

In RAMMS::Debris Flow one has the option to enter up to 10 points to define an inputhydrograph. It requires discharge Q, time t and velocity v at different times. A three-pointhydrograph for the event shown in Figs. 4.24 and 4.25 might look as following:

Table 4.3: Data for discharge hydrograph.

Discharge, Q [m3/s] Time, t [s] Velocity, v [m/s]Point 0 0 0 6Point 1 88 2.2 6Point 2 0 1500 3

The other option is to define total volume Vtot, corresponding maximum discharge Qmax andtime when the maximum discharge occurs tmax. The time of maximum discharge is typicallyobserved just upslope of the leading edge of the flow, probably on the order of a few secondsto perhaps a few 10’s of seconds after the arrival of a debris flow at any given location. Thisallows the calculation of the time at which the total volume passed the hydrograph location(tend). Discharge is linearly interpolated between known Q-values.

In both cases, the inflow direction has to be defined, which is described as the angle in counter-clockwise direction from the x-coordinate of the topographic data (Fig. 4.26).

Figure 4.26: Definition of inflow direction of an input hydrograph.



Exercise 4.5.d: How to use the input hydrograph.

Hydrograph location and calculation domain

◦ Draw a line which extends over the potential debris flow width with the releasearea tool (see section 4.5.1) where you want to place the input hydrograph (Fig.4.27). Be sure your release area covers several grid cells. The input will initiallyflow downhill perpendicular to the line.

◦ The inflow (release) height is always automatically set to 1 m. The height infor-mation does not influence the simulation, but is required for the input file and hasto be larger than 1 m, Fig. 4.28).

Figure 4.27: Line release area for the input hydro-graph inside the calculation domain.

Figure 4.28: Release heightrequired only for hydro-graph location.

◦ Draw a calculation domain (see section 4.5.3), such that the area of the inputhydrograph is located inside the domain.

Enter data of discharge hydrograph

◦ Once you start to RUN a calculation (see section 4.5.4) you can enter the dis-charge hydrograph information in the corresponding tab Hydrograph. For detailson how to enter the hydrograph data see section 4.5.4.



4.5.3 Calculation Domain

To reduce calculation time you can specify a smaller calculation domain to reduce the numberof computational cells. By analyzing a calculation with a coarse grid (large cell size), e.g. witha cell size of 5 or 10 m, you get an idea where the flow path is situated and you can limit thecalculation domain to the area of interest.

Switch to 2D mode and choose Input → Calculation Domain... → Draw New Domain or click. Now you can draw a polygon containing the area of interest analogously to drawing a new

release area (see exercise "Create release area" on page 36). We strongly recommend usingsmaller calculation domains especially if you calculate with small cell sizes (e.g. < 5m).

Figure 4.29: Calculation domain in green encloses the area of interest and reduces calculation time incomparison with the default rectangular domain which is automatically generated.



4.5.4 Running a calculation

To run a calculation you have to open a created project (section 4.3), load a release area(section 4.5.1), and a calculation domain. Below you find an example for running a calculationwith constant release height and constant friction parameters µ and ξ.

Exercise 4.5.e: How to run a calculation.

◦ To run a calculation choose Run→Run Calculation or click .◦ The RAMMS::Run Simulation window opens. Before clicking run calculation, you

should check the input parameters.

General(1) Project name.(2) Project info. You can change it by simply

typing into the field.(3) Additional information: calculation do-

main file and DEM file.(4) Select an output filename.(5) Check box Run in background: Op-

tion to run simulations in backgroundmode. The RAMMS interface remainsactive and allows the user to start e.g.new simulations.

Figure 4.30: General information.



Continuation of exercise 4.5.e: How to run a calculation.

ParametersSimulation Parameters:(1) Change grid resolution, if necessary.

The resolution should always be chosenso that important features of the ter-rain are represented in the terrain model.High resolution grids will extend your cal-culation time.

(2) Choose end time of simulation.(3) Choose dump-step interval.

The dump-step interval defines the res-olution of the animation of your simula-tion but has no effect on the simulationresults

(4) Keep the default value for density if nofurther informations on the debris flowmaterial is available (2000 kg/m3).

Figure 4.31: Calculation parameters.

(5) Keep the default value for the earth-pressure coefficient Lambda (1.00).The parameter Lambda modifies the longitudinal pressure gradients driving theflow. The default value 1.00 disables the effect of Lambda. The use of Lamdaother than 1.00 is only possible in 1st order numerical solver and will influence thesimulation results. A Lambda other than 1.00 can provide better simulation resultsbut the values have to be tested carefully. See section 5.4 for more explanations.

Numerical Parameters:(6) Change numerical solver, 1st or 2nd order scheme.

We recommend using 2nd order, because it provides more accurate solutions ofthe equations than 1st order. However if you encounter stability problems it maybe useful to run your calculation using the 1st order numerical scheme.

(7) Keep the default value for the Null-height H cutoff (0.000100 m).Unrealistic shallow flow heights of the simulation are eliminated to minimize nu-merical errors.




Mu/Xi(1) Enter the friction parameters µ and ξ. Start

first scenario simulation with default values(µ = 0.2, ξ = 200 m/s2). More information onfrictional resistance is given in sections 4.2.3and 5.1.

(2) Check box Define Additional MuXi Areas ifyou want to add polygon regions with differentµ and ξ values. e.g. to represent significantchanges in the channel, heavily forested areasor perhaps smooth roads. Load the correspond-ing polygon shapefiles and define µ and ξ formaximal two additional regions. Be very care-ful in using this feature!

Figure 4.32: Friction values.

Release(1) Check box Use block release: As an alterna-

tive to a simulation with a hydrograph.(2) Check box Edit hydrograph table: Activates

the table (7) and is an alternative to a 3-PointHydrograph Calculation (4).

(3) The hydrograph shapefile is displayed here andcan be changed.

(4) 3-Point Hydrograph Caluclation: Define adischarge hydrograph by entering total volumeV, maximum discharge Qmax, correspondingtime at which the maximum occurs (tmax) andvelocity v. Click on . The end time (tend)of the input hydrograph is then automaticallycalculated.

(5) Define the inflow direction of the debris flowat the hydrograph input location.

Figure 4.33: Release information.

If chek box ”Edit hydrograph table” (2) is activated:(6) The discharge hydrograph has to be defined in the hydrograph table (7).(7) Enter hydrograph points starting with 0 (indicating point 0 at time = 0 s).

Define for each point: time t, discharge Q, and velocity v. The number of hy-drograph points can be chosen (min. 3, max 10). More details on the inputhydrograph are given in section 4.5.2.




StopThe stopping criteria in RAMMS is based onthe momentum. In classical mechanics, mo-mentum p (SI unit kgm/s, or, equivalently,Ns) is the product of the mass and velocityof an object (p = mv). For every dump-step, we sum the momenta of all grid cells,and compare it with the maximum momen-tum sum. If this percentage is lower thana user-defined threshold value (see below),the program is interrupted and the flow isregarded as stopped. Threshold values be-tween 1-10% are reasonable, but this is onlya suggestion and must be empirically deter-mined for each test case.

Figure 4.34: Stop criteria.

WarningRAMMS is intended to be used as a tool to support debris flow experts. In somecases, especially when the duration of the input hydrograph is long, some usershave reported that the flow front continues to creep forward at a velocity which isjudged to be unreasonably slow for the field situation under investigation. If thisis the case, it may be reasonable to stop the simulation at an earlier time step orto use a larger value for the momentum cutoff to force the model to stop at amore realistic location. The RAMMS development team is investigating alternativeobjective criteria that will be incorporated into a future release of the model. Ifyou encounter this problem, please contact [email protected]




◦ Click run simulation (Fig. 4.33).◦ If you want to start several (up to 50) simulations automatically (e.g. over night)

use Track→New...→Run Batch Simulations. You can choose how many com-putional cores the Batch-Mode should use.

◦ The following window appears, showing the status of the calculation. (Fig. 4.35)(1) general information of the simulation, (2) output file, (3) starting the calculation(4) for every time step RAMMS calculates the maximal values (height, velocity andpressure) as well as the outflow mass, the moving momentum and the flow volume.

Figure 4.35: Status window of calculation.




◦ Once it’s finished, the simulation as well as the output logfile (see Fig. 4.38) areopened in RAMMS. If you ran the simulation in backround mode, you have clickon any button to finish the calculation. Afterwards the simulation is opened inRAMMS.

Figure 4.36: Main window in output mode.

◦ If mass flows out of the calculation domain, RAMMS shows an alert. (Fig.4.37).To get reliable results you should enlarge your calculation domain. (See section4.5.3)

Figure 4.37: Outflow volume alert.



4.5.5 Project information

Once a scenario within a specific project is calculated it is possible to open the output logfile (inoutput mode) including project settings and information as well as calculation specifications.You can open the project’s output log with Project→Output Log File. A window as shown inFig. 4.38 opens. This window provides information about your project and is the first thingto look at after running a simulation to check your simulation results.

(1) Information on simula-tion time and resolu-tion. Be sure thesimulation stopped dueto LOW FLUX. Other-wise the output TIMEEND CONDITION in-forms you, that your sim-ulation stopped beforethe debris flow reachedthe stopping criteria youdefined for the simulation(see section Stop p.48).

(2) Information on simula-tion results.

(3) Input logfile(see Fig.4.39)

1

3

2

Figure 4.38: Output Logfile.



The input logfile (included in the output logfile), however, can already be opened once aproject is created and before a simulation is performed.

There are two ways to view your project settings and information. First you can open yourproject’s input logfile (or output logfile, in output mode), or you can check your project’sregion extent and area in the debris flow panel in the region tab.

You can open the project’s input log file withProject→Input Log File. The following windowopens:

This window provides information about all yourproject’s input specifications, like number of nodesand cells, release areas, which DTM was used,the loaded map and ortho images as well as yourglobal simulation parameters.

Figure 4.39: RAMMS Project InputLog file.

To view the project coordinates, click the regiontab in your debris flow panel. The region tab listsX- and Y-Coordinates of the lower left (minimalvalues) and upper right (maximal values) corner(this are the coordinates you entered when creatingthe project) as well as the global minimum andmaximum of altitude (Z value). Additionally, thetotal region area is shown (in km2).

Figure 4.40: Region extent (X-, Y-and Z-Coordinates, total area).


4.6. VISUALIZATION AND ANALYSIS OF THE RESULTS

4.6 Visualization and analysis of the results

This section gives a short overview on what is possible in RAMMS to view and analyze thesimulation results. The interpretation of the results has to be done by an expert who is familiarwith the local as well as with the topographic and meteorological situation of the investigationarea.

RAMMS is a model and each model is a simplification of reality, therefore the simulationresults should not be analyzed without questioning them. We strongly recommend that allusers perform sensitivity studies.

4.6.1 Visualize different parameters

The drop down menu Results offers the following functions:

• Flow Height• Flow Velocity• Flow Pressure• Flow Momentum

• Max values (Height , Velocity , Pressure , Momentum)• DEM Adaptations (Add Deposition to DEM)• Flow Analysis (Summary of Moving Mass)• Friction Values (µ, ξ)

These results are all visualized by a colorplot in the topography. See exercise "Displaying maxvalues" on page 55.

4.6.2 Line profile and time plot

In the horizontal toolbar you find two further functions:

• Line Profile

• Time Plot

Line profileA line profile is a good alternative to the color plot if the flow height, velocity or pressure shouldbe known at a specific location. The graph shows the currently active parameter. Every lineprofile is saved in the file profile.txt in the project directory. If you want to keep this lineprofile, you have to save it, see exercise "How to draw a line profile" on page 56.



Time plotThis function provides a time plot at a single point. This is helpful when it is of interest toknow the values and maximum values at a specific location (e.g. at a building, dam, or a tree)through time. Every point is saved in the file point.txt and a point-info file point_info.txt isadditionally saved in the project directory. If you want to keep this point, you have to save it,see exercise "How to create a timeplot" on page 58. The point-info file can be visualized withExtras→Point...→View Point Info File.



Exercise 4.6.a: Displaying calculation values.

The maximum values of flow height, velocity and pressure give a good overview of thedimension of the debris flow. You find them underResults → Max values...

→ Max flow height

→ Max velocity

→ Max pressure

Figure 4.41: Results: Maximum values of flow height (left), velocity (middle) and pressure (right).

The flow height can be visualized exaggerated by a factor. Click Help → Advanced...→ Additional Preferences... → Edit to change the factor of the quasi 3D-visualizationof the flow height under the keyword exaggeration.

Figure 4.42: Quasi 3D-Visualization of flow height (left: exaggeration 1; right: exaggeration 5)



Exercise 4.6.b: How to draw a line profile.

a) Draw a new line profile:

◦ Switch to 2D mode by clicking .

◦ Activate the project by clicking on it once, then click or chooseExtras→Profile...→Draw New Line Profile.

◦ Define the line profile in the same way you specify a new release area. Finish theline profile with a right-click on the mouse button.

◦ A window opens, displaying the line profile.

Figure 4.43: Line profile plot.

- filled grey area active parameter (scale on left side).- red line active parameter (multiplied by 50) added to

the track profile (altitude, scale on the right side).- black line track profile (altitude, scale on the right side).- bottom scale projected profile distance (in m).

◦ If you change the active parameter, min or max values or the dump-step in RAMMS,the plot is directly updated. You can also start the simulation and then watch thetime variations in your line profile plot.

◦ It makes sense to either draw a profile line perpendicular to the flow direction or todraw the line along the flow path. Basically every imaginable path is possible.



Continuation of exercise 4.6.b: How to draw a line profile.

Figure 4.44: Line profile perpendicular todebris flow direction.

Figure 4.45: Line profile along the debrisflow path.

◦ To save the coordinates of the points belonging to the line profile, go onExtras→Profile...→Save Line Profile Points and enter a file name.

◦ To save the line profile parameters (distance in m and the active parameter, e.g.the flow height in m) at the current dump-step, go on Extras→Profile...→ExportProfile Plot Data and enter a file name.



Continuation of exercise 4.6.b: How to draw a line profile.

b) Load an existing line profile:

◦ Switch to 2D mode by clicking .

◦ Activate the project by clicking on it once and click or chooseExtras→Profile...→Draw New Line Profile.

◦ Click the middle mouse button once.◦ A window pops up and you can browse for the line profile you wish to open.

Exercise 4.6.c: How to create a time plot.

a) Select time plot point:

◦ Click or choose Extras→Point...→Choose Point.◦ Click into the map at the point where you want to create a time plot.◦ A window opens, displaying the time plot at the point of interest (active parameter

vs. time).

Figure 4.46: Time plot window.

◦ To save the point coordinates, choose Extras→Point...→Save Point Locationand enter a file name.

◦ To save the time plot data (time in s and the active paramter, e.g. the flow height,for every dump-step), choose Extras→Point...→Export Point Plot Data andenter a file name.



Continuation of exercise 4.6.c: How to create a time plot.

b) Load a time plot:◦ To reopen the time plot graph window of the last selected point, go on

Extras→Point...→Create Point Time Plot.

◦ To open an arbitrary time plot that was saved anytime before, click .◦ Click the middle mouse button once.◦ A window pops up and you can browse for the time plot file you wish to open.

c) Enter point coordinates and get a time plot:◦ Go to Extras→Point...→Enter Point Coordinates (X/Y).◦ Enter X-coordinate of your point of interest. Click OK.◦ Enter Y-coordinate of your point of interest. Click OK.◦ The time plot opens.



4.6.3 Creating an image or a GIF animation

ImageIt is possible to export your results as an image in different formats (e.g. .png, .jpg, .gif,.tif etc.). Choose or click Track→Export...→GIF Animation and define a new file namewith the corresponding extension. An image of the visible part in the viewer will then be saved.

GIF animationCreating a GIF animation is only possible in output mode. Click and wait until the simula-tion stopped and a window opened. Enter a file name and location. The GIF animation folderas well as the corresponding gif animation file is saved in the simulation folder. In the debrisflow tab in the preferences you can define the interval for the GIF animation (GIF animationinterval [s]). Only time steps, not maximum values can be saved as GIF animations.



4.6.4 Stopping mechanism

Check the output logfile under Project→ Output Logfile to verify your simulation stopped dueto low flux (see Output Logfile on page 51). Otherwise enlarge the end time of your simulation(see exercice ”Run a calculation” on page 46.) To check the stopping of your simulation clickResults → Summary of Moving Mass. A window similiar to Fig. 4.47 opens which shows thesummary of moving mass. For every dump-step, RAMMS summed up the momenta of all gridcells, and compared it with the maximum momentum sum. If this percentage is smaller thana user defined threshold value (see page 48), RAMMS abortes the simulation and the debrisflow is regarded as stopped.

2

1

Figure 4.47: Summary of moving mass.

Stopping criteria with large tresholdvalues (e.g. >10%) may result in un-realistically early stopping of a simulation.

Small threshold values however may leadto numerical diffusion of the simulationresults as shown in Fig. 4.47 (2) and veryslow creeping of the debris flow materialand velocity oscillations (see Fig. 4.48).

In the example shown in Fig. 4.47 thesimulation could be already stopped after12 dump-steps (1).



threshold: 0%

Figure 4.48: Stopping behavior of a RAMMS simulation. Small threshold values may lead to unlikelyslow creeping of the material. In the example shown in the figure above the stopping criteria is setto 0%.

Because block release simulations (the entire debris flow material starts to flow at the sametime) usually show larger values for the total maximum momentum than hydrograph simu-lations (controlled inflow of debris flow material into the calculation domain), the thresholdvalues for block release simulations could be set smaller than the threshold values for hydro-graph simulations in some situations (see Figs. 4.49 and 4.50 and section 5.2).

Whether or not a flow stops depends on terrain (slope angle in runout), total flow volumeand friction values and should always be evaluated by an expert. In case of doubt on how tochoose threshold values we recommend running a simulation with a 1% threshold and checkingthe summary of moving mass for numerical diffusion (Fig. 4.47) and analysing the debris flowrunout (flow height and flow velocity) with time plots (Fig. 4.47 and section 4.6.2).



10%

0% 1% 2% 3%

4% 5% 20%

Figure 4.49: Stopping behavior of a hydrograph RAMMS simulation. In this example threshold values<5% lead to numerical diffusion of the simulation results. A threshold value of 5% seems to beappropriate in this case.

10% 5% 20%

0% 1% 2% 3%

4%

Figure 4.50: Stopping behavior of a block release RAMMS simulation. In this example threshold values<2% lead to numerical diffusion of the simulation results. Threshold values of 2-3% seem to beappropriate in this case.



4.6.5 Numerical instabilities

Numerical instabilities can occur in RAMMS simula-tions (see Fig. 4.51).To detect them plot the maximal flow velocity (clickResults → Max Values... → Max Velocity or )

Figure 4.51: Numerical instabilities.

Numerical instabilities can happen because RAMMS employs 2nd-order numerical solutionmethods which can lead to problems, especially when topographic changes are large.

smooth terrain: there is no problem. Spatial gradients are constructedover several neighbour elements.

rough terrain: numerical instabilities may arise because it is difficult toconstruct reasonable gradients, especially velocity gradients over severalneighbour elements. This can result in unrealistic velocity peaks in thesolution.

There are different solutions to numerical instabilities (see Fig. 4.53):

If velocity peak Action• is local → ignore the outliers• has propagated away from the source → smooth the terrain

(mean filtering e.g. in Arc GIS Fig. 4.52) or→ run a 1st order calculation in RAMMS or→ change location of the release area or theinput hydrograph



Figure 4.52: Smoothed terrain (e.g. mean 5x5 filter in Arc GIS).

numerical issue 1st order simulation smooth terrain

Figure 4.53: Solutions to numerical instability problems.



4.7 Adding structures or deposition to DEM

The option of adding structures or deposition to DEM must be used with great care andshould not be used to design deflecting dams. Deflecting or catching dams can neither bedesigned directly with RAMMS nor can the residual risk below dams be calculated directlywith RAMMS. RAMMS takes important factors in dam design such as energy dissipation,dam geometry or debris flow deposits in front of a dam not properly into account. Damshave to be designed using well known standard engineering procedures, e.g. Johannesson etal. 2009 [8], Rudolf-Miklau and Sauermoser 2011 [12] and Rickenmann 1995 [10]. RAMMS iswell suited to calculate the key input factors for dam design such as flow height and velocity.The dam-option should however only be used to try to visualize the influence of guiding orsmall deflection of the debris flow mass. RAMMS cannot be used directly to evaluate if theheight of a deflecting dam is sufficient for a certain scenario or not (see explanations on page68).


4.7. ADDING STRUCTURES OR DEPOSITION TO DEM

4.7.1 Creating a dam

RAMMS offers the possibility to simulate the presence of a deflecting dam by increasing thealtitude at the position where a dam is considered. This option helps the user to design miti-gation structures and to test its influence on potential flow paths near populated areas (Figs.4.57 and 4.58).

Exercise 4.7.a: How to create a new DEM to simulate a dam.

◦ Create a polygon ("release area") where a dam is supposed to be built (Fig. 4.54).◦ Create a second, inner polygon, if you wish to have a two-stage dam.◦ Go on GIS→Add DAM to DEM....

You have two options ...→Enter Relative Dam Height or ...→Enter Dam Ele-vation

◦ You will be asked to "Open dam file (*.rel)". Select the shapefile you want to useas the outer edge of the dam.

◦ The question pops up, if you want to "Open 2nd dam shapefile (inner polygon)?"

• Click No to continue with the next step.• Click Yes to choose 2nd dam file (*.rel).

◦ Next step is to enter the total elevation height or the total relative height of thedam in meters. This is the elevation of the dam crest.

◦ If you loaded an outer polygon file, you will be asked to enter the intermediateheight (m) (height of the outer polygon file) as well.

◦ Finally you have to "Enter new DEM name". Your new DEM, containing the "dam"is created in the folder set as DEM directory (RAMMS preferences ).

Figure 4.54: Release area where a dam issupposed to be built.

Figure 4.55: Dam.



To run a simulation based on the new created DEM, you first have to create a new project.Do almost exactly the same as if creating a regular project without the dam information. Theonly important difference is that you have to choose the correct DEM-file manually during step2 of the project wizard.

Figure 4.56: Simulation without mitigation mea-sures.

Figure 4.57: Simulation with two dams built inRAMMS

While RAMMS is able to simulate the effect of a dam lying lateral to the direction of flowquite well, there might occur numerical problems if a dam lies perpendicular to the directionof flow (see Fig. 4.58).

• Because there is no energy dissipation due to collision with dams implemented in RAMMS,unrealsitically large flow velocities and flow heights may be simulated in front of a dam.

• The numerical solver used in RAMMS incorporates information from neighboring cells. Theeffect of dams with only one cell as dam side wall may therefore be difficult to simulate.

Figure 4.58: Comparison of the profiles of two mitigations measures in RAMMS


4.7. ADDING STRUCTURES OR DEPOSITION TO DEM

If you encounter problems with the simula-tion of mitigation measures as described,we suggest creating a DEM including adam in GIS, ideally using progressivelyincreasing side walls as shown in Fig. 4.59.

Figure 4.59: Dam with gradually rising side walls.

The interpretation of RAMMS simulations including mitigation measures such as dams (seeFigs. 4.57 and 4.58) has to be done by experts. In addition we recommend to always checkthe simulation results with engineering approaches.



4.7.2 Creating a new DEM with deposited debris material

It is possible to simulate multi-surge debris flow events to estimate how deposits from earliersurges can influence the flow of subsequent surges. One has to assume that the deposits froman initial surge are not entrained by subsequent surges. To do this, in the output mode, userscan select the option to add the flow height of a debris flow to the DEM at any arbitrarydump-step. Finally, a new project can be created based on the updated DEM.

Exercise 4.7.b: How to add debris flow deposition to new DEM.

◦ The deposition height is the flow depth at the end of a simulation when the flow isconsidered to have stopped moving (alternatively, earlier dump-steps may be usedif there are reasons to believe the flow should have stopped earlier). So first viewthe results at the last time step or a different time step, if desired.

◦ Go to Results→DEM Adaptations→Add Deposition to DEM.◦ Enter a new name for the new DEM.◦ The new DEM, containing the deposition information, is created. To run a simu-

lation based on this DEM create a new project and manually choose the DEM fileduring step 2 of the wizard as explained above for the dam.


5 Applications

RAMMS::Debris Flow can be initiated using either a block release (e.g. landslide release) or ahydrograph (flow discharge as a function of time). In some cases it may not be entirely clearwhich method is most suitable. In this section we describe some practical differences in modelresults which may occur depending on which method is used to start the flow in the model.

This chapter presents several topics relevant for the application of RAMMS::Debris Flow inpractice. Several examples of how to use RAMMS to simulate channelized debris flows (flowpaths of debris flow limited by topography, such as a mountain torrent) using either a blockrelease or an input hydrograph are summarized. Model calibration and the question how tocalculate model impact pressures are discussed.

5.1 Calibration

The following section is based on simulations run in 2011 with RAMMS::Debris Flow v1.4.

The calibration of the Voellmy friction model is one of the most important steps to get realisticand useful results. For the calibration procedure a well documented historical event is required.The historical event should be similar to the problem where calibration is required. Ideally,information should include flow heights and velocities at different locations in the torrent aswell as the material composition, information concerning different flow paths and the initialconditions such as the total and the initial volumes. In practice, it is difficult to collect exactdata on flow heights and velocities from field studies. However, field data can provide estimatesof total volume, flow paths, flow heights and material composition and sometimes even flowvelocities.

Here, an example is shown, which was used for the calibration of RAMMS::Debris Flow for thespecific case at Dorfbach, close to Randa (VS, CH). See Deubelbeiss and Graf, 2013 [6].

71

CHAPTER 5. APPLICATIONS

The following data was used to calibrate the model:

Table 5.1: Parameters for calibration for the case study of Dorfbach, Randa (CH).

Field investigationsCross sectional analysis Heights of levées or heights of marks on constructions,

estimation of velocity (splashing, superelevation)Flow paths Tracks of boulders, rocks and mudDeposition of material Lobes, levées and debris flow headsEstimation of total volume Retention basin in the runout zone plus

deposited material in torrent and receiving riverPhotographsRelease area Geometry of release areaFlow paths Deposited material analysed by aereal photographs

Field observations and investigations provided an estimate of a total volume of approximately10’000 m3. The aim was to calibrate the model by comparing flow velocities and flow heightsat two locations (Fig. 5.1a). The estimated values obtained from the field observations atthese locations are:

Table 5.2: Field estimations of height and flow velocity for the case study of Dorfbach, Randa (CH).

Max. flow height [m] Velocity [m/s]Location 1 2-3 3-4Location 2 2-3 1-2

Find the best-fit Voellmy friction coefficients (procedure)

To find the best-fit Voellmy friction coefficients (dry-Coulomb type friction µ and viscous-turbulent friction ξ) we suggest the following calibration procedure:

1. Define µ, which - as a first guess - is set to tan(α), where α ist the slope anlge in thedeposition zone. For the case in Dorfbach we defined µ ≈0.2 (α ≈15◦).Values of µ normally range between 0.05 and 0.4. Values of µ larger than 0.4 rarelyprovide useful simulation results.

2. ξ is more delicate to calibrate and we suggest starting with an initial guess of ξ =200m/s2. ξ describes the turbulent behavior of the flow. Typically small values of ξ arereported for granular flows while relatively large ξ values are sometimes associated withmuddy flows.


5.1. CALIBRATION

Table 5.3: Suggestions for setting the viscous-turbulent friction parameter ξ

Granular flow Mud flow(solid-dominated) (fluid-like)

Viscous-turbulent friction, ξ [m/s2] 100-200 ∗) 200-1’000 ∗)∗) These values are only suggestions not fixed definitions.

If the type of flow (granular or muddy) is not known, we suggest the following initalvalues of the Voellmy friction coefficients for the calibration:

Table 5.4: General suggestion for the inital values of the Voellmy friction coefficients used for thecalibration procedure

Initial values of the Voellmy friction coefficientsused for a calibration procedure with unknown flow type

Dry-Coulomb type friction µ [ ] 0.2Viscous-turbulent friction ξ [m/s2] 200

3. Vary µ around the initial definition with steps of ∓0.1 and ξ with steps of ∓100 m/s2.After comparing this initial results with field observations, start with a fine tuning andincrementally change µ and ξ around the initally-found best-fit values. To match thesimulation results with the flow heights and velocities from field observations at the givenlocations we found the following best-fit Voellmy friction coefficients for Dorfbach:

Table 5.5: Best-fit Voellmy friction coefficients for the case study of Dorfbach, Randa (CH).

Dry-Coulomb type friction µ [ ] 0.225Viscous-turbulent friction ξ [m/s2] 130

The best-fit Voellmy friction coefficients are now used to perform several simulations (Fig. 5.1).We performed an additional simulation with a small total volume (5’000 m3) to better modelthe observed flow path. This modification is justified because there are two main locationswhere deposition was observed during the event of June, 7, 2011. One location is out of Fig.5.1 around an elevation of 1’730 m and the second location coincides with location number(3) in the center of the channel. The simulation using a total volume of 10’000 and 5’000 m3

show the following flow heights and velocities at the two locations 1 and 2:



Table 5.6: Resulting maximum flow heights and velocities for total volumes of 10’000 and 5’000 m3

and µ =0.225 and ξ =130 m/s2.

Volume: 10’000 m3 Max. height [m] Max. velocity [m/s]Location 1 2.7 3.8Location 2 2.5 2.5Volume: 5’000 m3

Location 1 2.2 2.6Location 2 1.1 2

Figure 5.1: Simulations with best-fit parameters µ=0.225 and ξ=130 m/s2 for (a) a volume of 10’000and (b) 5’000 m3 and a DEM resolution of 2 m. The dashed line indicates the flow path of the eventfrom June 7, 2010.

Both simulations with volumes of 10’000 and 5’000 m3 show locations where the flow leavesthe channel (Fig. 5.1, locations 1-4), while in reality the debris flow should simply follow thechannel. Specifically, these are locations indicated by numbers (1) to (4). A breakout, wherethe flow left the channel, was observed only at location (2) on the orographic right side of thechannel.

These differences might be caused for the following reason: For these simulations we use aresolution of the DEM (2010) of 2 m. Additional simulations using a DEM-resolution of 1 mand a volume of 5’000 m3 could reproduce the flow path at location (1), (3) and (4). Atlocation (2) the outbreak disappearded in the simulation, although it occured in reality. Thisresult indicates that a resolution of 2 m cannot reproduce the exact flow paths because not allvertical curves are visible on a 2 m-DEM and therefore material can break out of the channel.The missing outbreak at location (2) for the 1 m-DEM can be explained as following: first, itmay indicate that at this location the volume was larger then 5’000 m3 and only after location


5.1. CALIBRATION

(2) more material was deposited and second, an aspect which will be disccussed in the nextsection (5.2), the use of a block release rather then an input hydrograph resulted in slightlyunderestimated flow heights and velocities.

To conclude, the simulations using a volume of 10’000 m3 indicate a slightly too high volumeestimation for the lower part of the torrent. However, to calibrate the Voellmy friction coeffi-cients it was still possible to match the flow heights and velocities observed in the field. Thesmall differences in the flow path between the simulation and reality can be explained by thenot ideally resolved terrain.



5.2 Input hydrograph in comparison with block release

The following section is based on simulations run in 2011 with RAMMS::Debris Flow v1.4.

With an input hydrograph it is possible to constrain the inflow of the debris material into thecalculation domain at a specific location. This is in contrast to a block release simulation,where a release area with an inital height is defined for which the entire block of materialis accelerated by gravity given the frictional resistance, e.g. simulating debris flow initiationas an instantaneous landslide failure. Flow height is a value that can be measured with anobservation station or estimated by geomorphic evidence. Assuming that the profile and thevelocity are known at the measurement location one can calculate the discharge hydrographthere. Other options are presented in section 4.5.2.

5.2.1 Comparison between a block release and an input hydrograph

Simulations with large volumes and a block release usually have larger maximal discharge values(maximum heights) compared to simulations using a hydrograph (Fig. 5.2a). The reason isthat for a block release the release area is definied and the inital release height has to beadjusted according to the total volume, specified by the user. This block begins moving assoon as the simulation is started. Hence, extremely large and possibly unrealistic initial heightscan occur (e.g. we use a initial height of 13.2 m for simulations with a total volume of 200’000m3 at Dorfbach) (see studies by Deubelbeiss and Graf, 2013 [6]). In many cases it would bemore reasonable to assume a realistic inital release height and adjust the release area to matchthe corresponding total volume. This effect inverts for small volumes: the inflow velocity ofa hydrograph simulation may be larger than what results from a block release simulation atthe location of the input hydrograph (Fig. 5.2b). The inverse effect is also visible in the flowpaths (Fig. 5.3). The larger flow heights and resulting velocities of a block release simulationare represented by the larger extent compared to a hydrograph simulation.


5.2. INPUT HYDROGRAPH IN COMPARISON WITH BLOCK RELEASE

Figure 5.2: Comparision of discharge curves of a simulation with a block release and a hydrograph for(a) a volume of 200’000 m3 and (b) a volume of 2’250 m3. For all simulations µ=0.225 and ξ=130m/s2. The discharge curves are measured at the location shown in Fig. 5.3.

Figure 5.3: Comparison of the inundated areas of a simulation with a block release and a hydrograph(a) for a volume of 200’000 m3 and (b) a volume of 2’250 m3. For all simulations µ=0.225 andξ=130 m/s2. Blue: hydrograph, red: block release. The red points indicate the location of themeasured discharge curves (Fig. 5.2).

5.2.2 Discussion

Two general problems appear when comparing the input hydrograph and block release: thefriction parameters for a large design event may be different than those for the calibrationevent, and differences in peak discharge. Large debris flows are often expected to have dispro-portionally longer runout in comparison with smaller flows (e.g. less friction, e.g. smaller µvalues). However it is difficult to generalize about how much the friction parameters should bechanged as a function of event volume. The situation is further complicated by the observationthat very large debris flows tend to take place as a series of surges rather than one large surge,and the effective flow topography may change due to deposition (or erosion) during the surge(see section 4.7.2). The problem with the unusually large flow depths and the input hydro-graph was described earlier in this section. Another aspect of that problem is that sedimententrainment often takes place along the flow path, a process which is not yet implemented in



RAMMS::Debris Flow (in development and testing as of this writing in 2013). Because themass has to be added to the model to achieve realistic results further down the slope, it isconvenient to approximate the volume increase simply by making the initial release area largerthan is reasonable in the field or by making the volume of the input hydrograph proportionallylarger. This is clearly a simplification, and we encourage users to review the results cautiously.

5.2.3 Summary

Using an input hydrograph rather than a block release certainly enhance the simulation resultsif data are available. In this case we can assume that the input parameters are well knownand represent the measured field data (at least at the measurement location). This way largeinitial release heights and the resulting large momenta can be avoided.

Channelized debris flows, which typically follow a torrent to the runout zone are more accuratelysimulated by input hydrographs. Additionally, the length of the flow path to be simulated canbe reduced resulting in shorter simulation times. (Be sure the entire hydrograph lies within thecalculation domain.) For hillslope debris flows, which typically occur in open, unchannelizedtopographies, a block release achieves better results.


5.3. EXAMPLE USING BLOCK RELEASE SIMULATIONS

5.3 Example using block release simulations

Illgraben, VS (CH)Simulations provided by Emch+Berger AG Bern, authored by Catherine BergerThe following section is based on simulations run in 2010 with RAMMS::Debris Flow v1.3.

5.3.1 Introduction

The Illgraben in the canton Valais, Switzerland, is one of the most active torrents in theAlps, with several debris flow events per year. The village Susten located on the Illgrabenfan is endangered by large debris flow events. Within the hazard mitigation project at theIllgraben, intensity maps for different event scenarios had to be developed and therefore theexisting hazard map was re-analyzed and verified considering additional debris flow event data.In a next step, various protection measures were studied. RAMMS::Debris Flow was used incombination with traditional estimates to analyze flow paths, flow behavior and the influenceof protection measures. Here, we focus on the calibration of the model.

5.3.2 Field setting

The Illgraben catchment (10.4 km2) located in southwestern Switzerland extends from the sum-mit of the Illhorn (2’716 m asl) to the outlet of the Illgraben into the Rhone River (610 m asl).The climate is temperate-humid and annual precipitation is relatively low. The subcatchment(4.6 km2) with debris flow activity is composed of quartzite, dolomite, limestone and schist,and slopes are very steep. The Illgraben fan has a radius of about 2 km, and the slope ofthe channel on the fan is 8% to 10%. The village Susten (community of Leuk) is locatedon the right side of the fan. The left side is covered by the Pfyn forest (protected area).After a large rock avalanche in 1961, the Illgraben channel was protected by a large sedimentretention dam in the middle section of the Illgraben trunk channel and additional 28 checkdams (CD) farther downstream (Hürlimann et al., 2003 [7]). A large variety of flow types hasbeen observed spanning the range from granular debris flows to muddy debris flows and floods.To take advantage of the frequent debris flow events, an observation station is run by WSLsince 2000 and debris flow properties and precipitation data are recorded automatically (e.g.,Badoux et al., 2009 [2]).



5.3.3 Modeling debris flows at Illgraben

Due to the research activity of WSL since 2000, a large debris flow dataset is available forthe Illgraben. This precondition is unusual and in many other modeling cases only a verysparse dataset of events is available. For this project 34 debris flow events from 2000 to2010 were considered (studies by Hürlimann, 2003 [7], Berger, 2010 [3] and unpublished WSLdocuments).

Calibration of the model

Using the debris flow data, return periods were determined (only maximum event volume inevery year considered) and relations between total event volume and front height, velocity anddischarge were studied. From these data, characteristic events (Table 5.7) with a good databackground were defined, which had to be reproduced in the calibration as closely as possible.

Table 5.7: Debris flow parameters used for the calibration of the model.

Parameter Volume 50’000 m3 Volume 100’000 m3

Front velocity on the fan [m/s] 4-6 6-8Flow height at CD27 [m] 1.5-2 2.5-3Maximum front discharge [m3/s] 75-125 100-200

Calibration started with the debris flow event having a total volume of 50’000 m3 and frictionparameters were first set at µ =0.1 (corresponding to the slope in the channel in the runoutzone) and ξ =200 m/s2 (according to the typical mixture of observed debris flows). Severalsimilar debris flows were observed during the last years and flow behavior is therefore welldocumented. With the initial friction parameter combination, flow velocity was too low (2-3 m/s on the fan). Finally, flow properties and behavior were reproduced the best with theparameter combination µ =0.07 and ξ =400 m/s2. Setting µ =0.07 corresponds approximatelyto the average slope of the fan. Maximum front velocity and flow depth at the apex and onthe lower third of the fan (at check dam (CD) 27) obtained with this parameter combinationare summarized in Table 5.8.

In a next step, the event with 100’000 m3 was modeled and the same friction parameters asfor the smaller event (0.07/400) were used first. Flow velocity was too low and finally, frictionparameters were set at µ=0.07 and ξ=500 m/s2. Because of the long travel distance fromthe apex to the lower third of the fan and outbreak with loss of material, flow velocities aresimilar at the lower line profile for both calibration volumes (Table 5.8). Larger values for ξresulted in even lager (unrealistic) velocities at the apex but with a moderate influence on thevelocities on the lower part of the fan.



Figure 5.4: The release area (27’900 m2) (red area) waslocated in the lower reach of the active debris flowcatchment and the digital terrain model DTM AV byswisstopo with 2 m grid size was used for the simu-lations. Density of the debris flow mixture was set at2’000 kg/m3 (typical value for the Illgraben). The lo-cation of the line profiles at the apex of the fan andthe lower third of the fan (check dam 27) are indicatedwith red lines.

Table 5.8: Resulting maximum flow heights and velocities for total volumes of 50’000 m3 with µ=0.07and ξ=400 m/s2 and for 100’000 m3 with µ=0.07 and ξ=500 m/s2.

Volume: 50’000 m3 Max. height [m] Max. velocity [m/s]Fan apex 3.9 5.9Lower 3rd of fan (CD 27) 1.9 4.3Volume: 100’000 m3

Fan apex 6.4 8.7Lower 3rd of fan (CD 27) 2.6 5.9

5.3.4 Problems and difficulties

The large area we had to model (distance from the release zone to the outlet of the Illgrabeninto the River Rhone about 4 km) caused very long lasting simulation runs and large outputfiles. Due to the long simulation runs, modeling was spread over many days making it difficultto perform sensitivity tests.

A test with a release zone higher up in the catchment revealed a large influence on thesimulation results and different friction parameters would have been chosen. However, wehad to define the release zone as close to the outlet as possible, still reaching the predefinedvelocities at the fan apex, to minimize simulation time. A hydrograph input-possibility wouldhave reduced this problem. (Explanatory note by the RAMMS manual authors: At the timewhen these simulations were performed, the input hydrograph model was not yet available.)



A better grid size resolution was not available for the Illgraben. However, we probably wouldnot have been able to use higher resolution data due to the even longer simulation runsand larger file sizes. Resampling the DTM AV to a coarser grid might have helped for firstmodel runs. However, for final simulations we used the DTM AV to obtain the most accuratesimulation results.

Spill over was observed in curves and complicated the interpretation of the simulation results.These outbreak locations had to be analyzed carefully to decide if there was a real weak point.An example for spill over is shown in Fig. 5.5.

Figure 5.5: (a) Simulations with best-fit parameters µ=0.07 and ξ=400 m/s2 for a volume of50’000 m3. (b) Profile where spill over was observed (profile location indicated by red line in (a)).



5.3.5 Summary of input parameters for simulations at Illgraben

Input parameters used for the simulations presented here are summarized in the following table:

Table 5.9: Input parameters for simulations at Illgraben (VS,CH).

Simulation detailsTerrain model DTM AV (swisstopo, 2005)Numerical scheme Second orderH cutoff 0.0001Stopping criteria 5% momentum tresholdParametersTotal volume [m3] 50000 100000Release area Above check dam 1, area 27900 m2

Release height [m] 1.8 3.58µ [ ] 0.07 0.07ξ [m/s2] 400 500λ [ ] 1 1



5.4 Active–passive earth-pressureIt is possible to use activ–passive earth-pressure coefficients in RAMMS to modify the longi-tudinal pressure gradients driving the flow. Active refers to the dilatant flow regions ∇·U ≥ 0and passive to compressive regions ∇ · U < 0. Typically the active–passive earth-pressurecoefficient is defined using Rankine’s earth-pressure theory

ka = tan2(45− φ

2 ) (5.1)

and

kp = tan2(45 + φ

2 ) (5.2)

where φ is the internal friction angle. This implies that ka = 1/kp. In RAMMS a friction angleis not specified; rather the passive earth-pressure coefficient is specified directly and the activeearth-pressure coefficient is defined as the inverse, 1/kp.

The use of active–passive earth-pressure coefficients is a subject of some debate in avalancheand debris flow science. Active–passive earth-pressure coefficients were first introduced intosnow avalanche science by Salm in 1966 to account for the fact that flowing snow exhibitsboth solid and fluid-like behavior. Passive earth-pressure coefficients were used to account forthe internal energy dissipation, especially during obstacle interaction. However, there appearsto be no independent means to experimentally determine the active–passive earth-pressurecoefficients. For soils and snow there are methods to estimate it (see Salm, 1993 [14]).

The use of active–passive earth-pressure coefficients will greatly affect the simulation results.With larger passive earth-pressure coefficients, the smaller the debris flow heights, thereforethe larger the longitudinal expansion of the debris flow, especially in the runout zone. Largerrunout distances are produced. Because of this effect, different Voellmy parameters, µ andξ, are often required to calibrate the same event, when the kp value changes. Therefore, werecommend keeping the kp value constant during the event calibration stage of the simulationprocess.

Active–passive earth coefficients can cause numerical instabilities. Because values of kp 6= 1,modify the longitudinal stress distribution, unphysical numerical results are possible, especiallyfor values much larger than one. Large passive earth-pressures can modify the mass flux,especially on steep slopes, such that no mass remains in the cell volume. The resultingnegative flow heights trigger numerical problems. Within the flow, active–passive zones canbe located near to each other leading to velocity oscillations. Values of kp>5 are thereforenot recommended.


5.4. ACTIVE–PASSIVE EARTH-PRESSURE

There are several ways to ameliorate the numerical problems. We have found that first ordersolutions are more stable with larger kp values. We therefore recommend using first ordersolutions when kp > 1. Second order solutions should only be used when kp = 1. The massbalance of the events should always be carefully controlled as this is the best indication ofnumerical problems.

Figure 5.6: Lambda=1.0 and Lambda=2.5 for a block release.

Figure 5.7: Lambda=1.0 and Lambda=2.5 for a hydrograph release.



5.5 Calculation of impact pressures

Debris flow experts often need to calculate the expected impact pressure on an object todesign a structure (walls, columns, etc.) or to consider additional mitigation measures toprotect buildings.

Impact pressures p depend on the debris flow velocity U , the density ρ and the shape of theobstacle, which is expressed with the drag coefficient Cd and is given by

p = 0.5CdρU2. (5.3)

By default RAMMS::Debris Flow takes Cd=2.0 (corresponding to long walls), but smallervalues of Cd might be called for. Presently, we recommend:

• Cd=0.5 for thin, small obstacles such as cables and wires.The drag coefficients are small, because the flowing material can easily flow around suchsmall structures.

• Cd=1.0 for larger obstacles such as columns and supports as well as building corners.Here too, the flows can flow around these small objects without diverting the mainportion of the flow.

• Cd=2.0 for dams and walls that strongly divert the flow.The normal pressure pN acting on walls is

pN = psin2(α), (5.4)

where α is the angle of diversion. The shear stress pS acting on the wall is then pS=µpN

where µ is the coefficient of friction depending on the wall roughness.

We further recommend consulting the guidlines of your country for property protection relatedto natural hazards. In Switzerland these guidlines are summarized in ”Richtlinie Objektschutzgegen Naturgefahren” 1.

It is not possible for users to change Cd automatically. If you wish to consider different Cd-values you have to adjust the resulting impact pressure values manually. Recall that RAMMSdefined the value for Cd=2.0. If you wish, for example, to consider Cd=1.0 you should dividethe resulting impact pressure by two (p/2).

1Authored by Egli T., Egli Engineering AG, St. Gallen. Licenced by Gebäudeversicherung Kanton Zürich,Baudirektion Kanton Zürich (AWEL) Amt für Abfall, Wasser, Energie und Luft and GebäudeversicherungsanstaltKanton St. Gallen.


6 Program overview

RAMMS is a windows-based program that relies on drop-down menus and dialog boxes to setthe model parameters, run calculations and view results. Toolbar buttons are also availableand provide short-cuts of the menu paths; moving the cursor over a button results in a shortexplanation, appearing in a text box below the cursor (’tooltip’). For functions not availablein the current context, the menus and buttons are deactivated and cannot be used.

6.1 The Graphical User Interface (GUI)

The graphical user interface (GUI) (Fig. 6.1 on page 87) consists of menu bar, horizontal andvertical toolbar, main window, time step slider, right and left status bar, colorbar and panel.They will be explained in the following sections.

Figure 6.1: Graphical user interface (GUI).

87

CHAPTER 6. PROGRAM OVERVIEW

6.1.1 The menu barTrackSimilar to the Microsoft Windows File menu, Track is used to open, close, save, print, backupand export files.

New... I Project Wizard Start a new project, guided by the wizard (Ctrl+w).I Convert XYZ →ASCII grid

Convert laser scanning data into a ESRI ASCII grid.

I Run BATCH simula-tions

Possibility to start up to 50 simulations automatically (e.g.overnight). You can choose how many computational coresthe Batch-Mode should use (quasi parallel simulations, savescomputionals time).

Open... I Input File Open an existing input file (*.db2) (Ctrl+O).

I Debris Flow Simula-tion

Open existing debris flow simulation (select the folder con-taining the simulation files) (Ctrl+A).

Close Close active file (input or output).Save Save active file (Ctrl+S).

Save Copy As Save a copy of the active file (e.g. test.db2) under a newname (e.g. simulation1.db2, works only in input mode). But,RAMMS stays with the active file (test.db2)!

Export... I Export Image File Create an image of the active window in a chosen format. Youcan choose the desired image format using the file extension(e.g. .png, .jpg, .gif, .tif etc.).

I Export GIF Anima-tion

Create a GIF animation of the simulation (only in outputmode). Change GIF animation interval (s) in the preferences.

Backup... I Backup RAMMS Ver-sion

Make a backup of the current RAMMS version.

I Backup ActiveProject

Backup your active project. The user will be asked if hewants to include output files in the backup. This functionis useful when having problems with a simulation. Make abackup and send the zip-file together with some explanationsto [email protected]. Make sure that all your input data (releasearea shapefiles, domain files, etc...) is in the project folder.

I Backup User DefinedFiles/Folders

Backup any folder or files you want.

Preferences Change RAMMS preferences.

Log files... I RAMMS Logfile (cur-rent)

Show active RAMMS logfile.

I RAMMS Logfile (lastsession)

If RAMMS crashed, open this logfile and copy/paste the con-tent into an email to [email protected].

Exit Exit RAMMS (Ctrl+Q).


6.1. THE GRAPHICAL USER INTERFACE (GUI)

EditThis menu is used to edit colorbar and dataspace properties.

Edit Colorbar Properties Edit the colorbar properties.

Edit Dataspace Properties Edit your dataspace properties.Show Dataspace Axes Shows or hides dataspace axes of the project region. The axes

can be only visible if the background color is set to white.Colorbar White Color Defines the text-color of the colorbar (black or white).

InputMenu used to specify the global parameters, the calculation domain, release area, frictionparameters and forest cover. This menu is active only in input mode.

Calculation Domain... I Draw New Calcula-tion Domain

This activates the button to draw a new cal-culation domain. The mouse cursor changesto an arrow.

I Load Existing Domain Load a existing calculation domain (*.dom)drawn and saved before.

Release Area... I Draw New ReleaseAreas

This activates the button to draw new re-lease areas. The mouse cursor changes to anarrow.

I Load Existing ReleaseAreas

Load an existing release area shapefile.

I Details/Edit ReleaseAreas

The mouse cursor changes to an arrow andyou can select release areas to define the re-lease height and to view release area infor-mation. This works only in 2D mode.

I Crop Release Area If your release area shapefile consists of sev-eral polygons, you can crop some of themand create a new release shapefile.



ShowThis menu enables and disables the different visualizations. A little arrow indicates if thevisualization is enabled or disabled.

Show Lights Show/hide light effects

Show Grid Show/hide computational grid

Show Map Show map

Show Image Show orthophoto/image

Show Release Area/Simulation Show/hide release area (input mode) or simulation results(output mode)

Show Isotropic View Switch between realistic (isotropic) and anisotropic view

Show Colorbar Show/hide colorbarShow Bottom Color Show/hide 0-colorShow Arrow OUTPUT | Show/hide point arrow of time plotShow Line Profile OUTPUT | Show/hide line of line profileShow Domain Show/hide calculation domain area (only in input mode)

RunThis menu is active only in input mode.

Run Calculation Opens the module parameter window to change parametersand to start the calculation of a debris flow simulation.



ResultsThis menu contains the results functions and is only active in output mode.

Flow Height Shows flow height of the debris flow for everytime step.

Flow Velocity Shows flow velocity of the debris flow for ev-ery time step.

Flow Pressure Shows flow pressure of the debris flow forevery time step.

Flow Momentum Shows flow momentum of the debris flow forevery time step.

Max Values... I Max Flow Height Displays the maximum flow height for eachcell.

I Max Velocity Displays the maximum velocity for each cell.

I Max Pressure Displays the maximum pressure for each cell.I Max Flow Momen-tum

Displays the maximum momentum for eachcell.

Add Deposition to DEM Adds the deposition of an debris flow simu-lation to a new DEM.

Summary of Moving Mass Summarizes the Moving Mass.Mu Display the friction parameter µ for this sim-

ulation.Xi Display the friction parameter ξ for this sim-

ulation.



GISThis menu contains GIS functions.

Import Polygon Shapefile Import an ESRI GIS polygon shapefile.Convert Polygon Shapefile... Convert a normal polygon shapefile into a RAMMS release

file or a RAMMS forest file. This function makes only sensein the input mode.

Export Results As Shapefile Export the active results to an ESRI GIS shapefile for lateruse in a GIS program.

Export Results As ASCII grid Export the active results to an ESRI ASCII grid for later usein a GIS program.

Add Dam to DEM... Adds a dam to the DEM. You have to specify relative damheight or absolute dam elevation.

Show Slope Angle (◦) Display the slope angles.

Show Curvature (1/m) Display the curvatures.

Show Contour Plot Display a contour plot.



Extras

Add/Change or Remove map Add or change the topographic map of your project. Themaps have to be located in your distribution’s ’Map’ folder,see section 3.6 for details. If not, you can browse for themaps.

Add/Change or RemoveImagery

Add, change or remove the imagery used for visualization ofyour project. The images have to be located in your distribu-tion’s ’IMAGE’ folder, see section 3.6 for details. If not, youcan browse for the images.

Point... Used to select points in output mode, save point locationsand export Time Plot Data.

Profile... Used to draw a profile in output mode, save profile points andexport Profile Plot Data.

Save Active Position Save your current state of view, as well as the enabled anddisabled visualizations.

Reload Position Reload your saved position.Google Earth... This function exports release areas and your results to Google

Earth. See Map Options for map settings for areas outside ofSwitzerland.

View input file Opens the input file in a window.



ProjectThis menu contains the project input and output logfiles.

Input Log File Displays the input logfile.Output Log File Displays the output logfile. The input logfile is appended to

the output logfile.

Open Project Folder (Windows Ex-plorer)

Opens project Folder in Windows Explorer from withinRAMMS.

Get Colorbar Brings a ’lost’ colorbar back on screen.

Help

Manuals... I User Manual (PDF) RAMMS User Manual.RAMMS web RAMMS Homepage at

http://ramms.slf.ch

Updates Download RAMMS updates manually or di-rectly from the web

Advanced... I Color Tables I View Available Color TablesChoose a different type of color scheme forcolorbar

I Additional Prefer-ences

I Edit

Only for experts. Please contact theRAMMS Administrator if you have questions.

I Reset General Prefer-ences

I Resets your preferences to the generalpreferences.Choose a different type of color scheme forcolorbar

About RAMMS About dialog windowLicense Agreement RAMMS License AgreementRAMMS Changelog Information about the RAMMS release and

changes


http://ramms.slf.ch


6.1.2 Horizontal toolbar

Project wizard: open debris flow wizard for creating a new debrisflow project. (Ctrl+w)

Open input file. (Ctrl+O)

Open simulation. (Ctrl+A)

INPUT | Save copy as: save the active file under a new name.

INPUT and OUTPUT | Close: close the active file.

Print: displays the Windows print manager.

Undo, Redo.

Arrow (move and resize), Rotate, Move.

Simulation Results: Choose this function and move the arrow overthe topography → x-, y- and z-Coordinates of the mouse positionare shown in the lower right status bar (see below).OUTPUT | If you move the arrow over the simulation data, theactive parameter is shown as well (see right value in the figurebelow). If you click once with the left mouse button at a point ofinterest, a new window pops up called ’RAMMS::Debris Flow TimePlot <Active Parameter>’.

INPUT, 2D | Crop Release Areas: Click this button to make aselection of the release area polygons you want to crop.

INPUT, 2D | Create new release area: specify new polygon-pointsby clicking the left mouse button, for the last polygon-point clickthe right mouse button to finish. The user is asked if he wants todraw more release areas. At last, he has to specify a new filenamefor the release area.

INPUT, 2D | Create new domain area: specify a new domain poly-gon by clicking with left mouse button, for the last polygon-pointclick the right mouse button to finish. A dialog box will then askthe user for a new domain name (e.g. test).



OUTPUT, 2D | Line Profile: Select the topography, until the Line-Profile-Button is active. Click the button and then move the cursorto the start point of your profile. Click the left mouse button andmove the cursor to the next position of your profile. At the endposition of your profile click the right mouse button. A new win-dow pops up called ’RAMMS::Debris Flow Line Profile Plot ActiveParameter’. This line profile plot is linked to your simulation. If youchange the parameter or if you change the max-value in the debrisflow panel, the changes are adapted in the line profile plot!

INPUT, 2D | View and Edit Release Areas.

Zoom tools.

Annotation tools: text, line, rectangle, oval, polygon, freehand.They can be activated and deactivated in the additional preferences.Preferences → Advanced... → Edit → Annotations

Interpretation of the input DEM: Slope Angle, Curvature and Con-tour Plots. Remove visualization by clicking the button again.

OUTPUT | Show Maximum values of the simulation results: Max.Flow Height, Max. Flow Velocity and Max. Pressure.

OUTPUT, 2D | create a time plot for the last point location.

OUTPUT | export the results to ASCII grid.

Open project folder in Windows Explorer.

Add/change maps/orthophotos.



6.1.3 Vertical toolbar

Add shapefile (*.shp).

Switch to input file of an already open simulation.

Show/hide lights.

Show/hide mesh.

INPUT | Show/hide release area (or other active parameter).OUTPUT | Show/hide simulation.

Show/hide colorbar.

Show map.

Show image.

INPUT | Run Simulation.OUTPUT | Animate Simulation / Continue Simulation.

Stop/Pause Simulation ( ).

OUTPUT | End Simulation: skip to last dump-step of simulation.

Create a screenshot of the main window.

OUTPUT | Create GIF animation.

Edit colorbar properties.

Edit dataspace properties.

Change RAMMS preferences (e.g. working directory).

Change view to 2D / Change view to 3D ( ).



6.1.4 Main window

All input and output related visualizations are displayed in the main window.

6.1.5 Time step slider (only in output mode)

The time step slider can be moved manually to change the active time step.

Figure 6.2: The active time step (139) is shown in the time step slider.

6.1.6 Left status bar

The left status bar is used to display status information for operations or informational mes-sages pertaining to the currently selected surface or manipulators.

Figure 6.3: Status information shown in the left status bar.

6.1.7 Right status bar

The right status bar is used to display the position of the cursor within the surface andadditional simulation results at the position of the cursor.

Figure 6.4: Position information and triangle simulation results in the right status bar.



6.1.8 Colorbar

In general, the colorbar appears at the rightedge of the main window (Fig. 6.1) and canbe moved and resized (see exercise "Editingthe colorbar" on page 31). Figure 6.5: Colorbar



6.1.9 Panel

A debris flow panel is displayed on the right side of the RAMMS GUI (Fig. 6.6), and consists offour tabs (General, Display, Volumes and Region). This panel changes interactively, dependingon what parameter is displayed in the main window. The current parameter (A,1) and allvisualizations (A,2) are additional information/functions on the debris flow panel. The releasearea or the hydrograph location can be acitvated (A,3) and the corresponing location is shown(A,4.)

Figure 6.6: Debris flow panel.



General tabThe general tab (A) shows some important simulation parameters, such as: nr. of nodes, nr.of cells, end time (s), dump-step (s), grid resolution (m) and density (kg/m3).

Display tabThe display tab (B) shows parameters that are important for the display (colors, transparency)of results and polygon shapefiles. The min. and max. values as well as the number of colorsinfluence directly the colorbar and the visualization. The transparency of the simulation resultscan be changed on the debris flow panel, tab display. 0% means no transparency, 100% meanstotal transparency, see figure below (Fig. 6.7). The colorbar is devided into n (nr. of colors)different colors, where the lowest color is normally not displayed. The bottom line informs theuser of the range of values that are not displayed in the current visualization (only in outputmode).

Figure 6.7: No transparency (left) and 40% transparency (right) of simulation result.

Volume tabThe volume tab (C) gives the user information about the release area, such as projected releasearea, 3D release area, estimated release volume (input mode), release mass (input) and calcu-lated release volume (output). If the simulation resolution corresponds to the input resolution,the estimated volume is very accurate. For different simulation resolutions, the estimation isless precise.

Region tabThe region tab (D) gives information about min and max X-, Y-coordinates and the altitudelimits as well as an information about the region area in km2.



6.2 File management

6.2.1 Software RAMMS

After the installation of RAMMS, the installation directory contains the following folders:

<installation_directory>

bin This folder contains all RAMMS executable-files.bmp Bitmap-files, used for toolbar buttons.defaults This folder contains some default files.IDL82 This folder contains the IDL Virtual Machine distribution.language This folder contains language files.license This folder contains your license files.Manual This folder contains the manuals and publications.Temp This folder contains some temporary files.

Additionally, the installation directory contains also the following files:

<installation_directory>

ramms.exe Start RAMMS with this exe-file.ramms.ico The RAMMS icon.ramms.ini The ini-file belongs to the ramms.exe-file.ramms.sav The main compiled program file.ramms_init.sav Additional compiled program file.uninstall.exe Uninstall RAMMS with this exe-file.uninstall.ini The ini-file belongs to the uninstall.exe-file.


6.2. FILE MANAGEMENT

6.2.2 Organizing your data

Recommendation to organize your RAMMS-data (this is only a recommendation, but it provedto be a good way):

Create a folder RAMMS (not in your installation directory, use another drive for your projectsand data) e.g. D:\RAMMS and in there the following folders:

• PROJECTS• DEM• MAPS• ORTHOPHOTO

It is important, that the DEM files, as well as your georeferenced maps and imagery, are locatedin the appropriate folders. These folders are the ones selected in the RAMMS preferences (howto set the correct folders see section 3.6).

IMPORTANT: There should be no blanks or special characters in all the above directo-ries. For example, do not specify a working directory like C:\Documents and Settings\EigeneDateien\Data etc...this will not work for RAMMS.


7 References and further reading

7.1 ReferencesMaps and aerial images

• All topographic base maps and aerial images are reproduced c©2010 swisstopo(BA091601).

Literature

[1] Ayotte, D. and Hungr, O., 2000: Calibration of a runout prediction model for debrisflow and avalanches. In: Debris-Flow Hazards Mitigation: Mechanics, Prediction andAssessment, edited by Wieczorek and Naeser, Rotterdam, 505-514.

[2] Badoux, A.; Graf, C.; Rhyner, J.; Kuntner, R. and McArdell, B.W., 2009: A debris-flowalarm system for the Alpine Illgraben catchment: design and performance. In: NaturalHazards, 49(3), 517-539.

[3] Berger, C., 2010: Debris flow entrainment and sediment transfer processes at the Illgrabencatchment, Switzerland. Ph.D. thesis, University of Bern, Inst. of Geological Sciences,Bern, Switzerland.

[4] Bovis, M.J. and Jakob, M., 1999: The role of debris supply conditions in predicting debrisflow activity. In: Earth Surface Processes and Landforms, 24, 1039-1054.

[5] D’Agostino, V. and Cesca, M., 2008: Ricostruzione di alcuni dei principali eventi torrentiziavvenuti in Provincia di Trento. Technical report, Trento Autonomous Province.

[6] Deubelbeiss, Y. and Graf, C., 2013: Two different starting conditions in numerical debrisflow models - Case study at Dorfbach, Randa (Valais, Switzerland). In: Graf, C. (Red.)2013: Mattertal - ein Tal in Bewegung. Publikation zur Jahrestagung der SchweizerischenGeomorphologischen Gesellschaft 29. Juni - 1. Juli 2011, St. Niklaus. Birmensdorf, Eidg.Forschungsanstalt WSL, 125-138.

[7] Hürlimann, M.; Rickenmann, D. and Graf, C., 2003: Field and monitoring data of debris-flow events in the Swiss Alps. In: Canadian Geotechnical Journal, 2003, 40(1), 161-175.

105

LITERATURE

[8] Johannesson et al., 2009: The design of avalanche protection dams. Recent practical andtheoretical developments. European Commission. Directorate General for Research, 2009.

[9] Mizuyama, T.; Kobashi, S. and Ou, G. 1992: Prediction of debris-flow peak discharge.Proceedings of the international Symposium Interpraevent, Bern, Switzerland, 4, 99-108.

[10] Rickenmann, D., 1995: Beurteilung von Murgängen. In: Schweiz. Ingenieur und Architekt113(48), 1104-1108.

[11] Rickenmann, D., 1999: Empirical relationships for debris flows. In: Natural Hazards, 19,47-77.

[12] Rudolf-Miklau, F. and Sauermoser, S., 2011: Handbuch Technischer Lawinenschutz. Ernst& Sohn GmbH&Co.

[13] Salm, B.; Burkard, A. and Gubler, H., 1990: Berechnung von Fliesslawinen: eine An-leitung für Praktiker mit Beispielen. Mitteilung 47, Eidg. Institut für Schnee- und Law-inenforschung SLF.

[14] Salm, B., 1993: Flow, flow transition and runout distances of flowing avalanches. In:Annals of Glaciology 18, 221-226.

[15] Varnes, D.J., 1978: Slope movement types and processes. In: Land-slides Analysis andControl, edited by Schuster, R.L. and Krizec,R.J., Spec. Per. Natl. Res. Counc. Transp.Res. Board, 176, Natl. Acad. of Sci., Washington D.C., 11-33.


7.2. PUBLICATIONS

7.2 Publications

The development of RAMMS is based on scientific findings published in international scientificjournals. A list of the most important scientific publications about RAMMS and its applicationsis given below (chronological order):

• Bartelt, P.; Bühler, Y.; Buser, O.; Christen, M. and Meier, L. 2012: Modeling mass-dependent flow regime transitions to predict the stopping and depositional behavior ofsnow avalanches, J. Geophys. Res., 117, F01015, doi:10.1029/2010JF001957

• Christen, M.; Bühler, Y.; Bartelt, P.; Leine, R.; Glover, J.; Schweizer, A.; Graf, C.;McArdell, B.W.; Gerber, W.; Deubelbeiss, Y.; Feistl, T. and Volkwein, A., 2012: In-tegral hazard management using a unified software environment: numerical simulationtool "RAMMS" for gravitational natural hazards. In: Koboltschnig, G.; Hübl, J.; Braun,J. (eds.) 12th Congress INTERPRAEVENT, 23-26 April 2012 Grenoble - France. Pro-ceedings. Vol. 1. Klagenfurt, International Research Society INTERPRAEVENT, 77-86.

• Christen, M.; Gerber, W.; Graf, Ch.; Bühler Y.; Bartelt, P.; Glover, J.; McArdell, B.;Feistl, T. and Steinkogler, W., 2012: Numerische Simulation von gravitativen Naturge-fahren mit "RAMMS" (Rapid Mass Movements). Zeitschrift für Wildbach-, Lawinen-,Erosions- und Steinschlagschutz, 169, 282-293.

• Bühler, Y.; Christen, M.; Kowalski, J. and Bartelt, P., 2011: Sensitivity of snow avalanchesimulations to digital elevation model quality and resolution. Annals of Glaciology,52(58), 7280.

• Christen, M.; Kowalski, J. and Bartelt, P., 2010: RAMMS: Numerical simulation of densesnow avalanches in three-dimensional terrain, Cold Regions Science and Technology, 63,1 - 14.

• Christen, M.; Bartelt, P. and Kowalski, J., 2010: Back calculation of the In den Arelenavalanche with RAMMS: Interpretation of model results. Annals of Glaciology, 51(54),161-168.

• Sartoris, G. and Bartelt, P., 2000: Upwinded finite difference schemes for dense snowavalanche modelling. International Journal for Numerical Methods in Fluids, 32, 799-821.

• Bartelt, P.; Salm, B. and Gruber, U., 1999: Calculating dense-snow avalanche runoutusing a Voellmy-fluid model with active/passive longitudinal straining. Journal of Glaciol-ogy, 45(150), 242-254.


List of Figures

3.1 Installation - welcome dialog window. . . . . . . . . . . . . . . . . . . . . . . 63.2 Installation - readme dialog window. . . . . . . . . . . . . . . . . . . . . . . . 63.3 Installation - license agreement dialog window. . . . . . . . . . . . . . . . . . . 73.4 Installation - destination directory dialog window. . . . . . . . . . . . . . . . . 73.5 Installation - installing files dialog window. . . . . . . . . . . . . . . . . . . . . 83.6 Installation - finished installing files dialog window. . . . . . . . . . . . . . . . 83.7 Installation - finished installation dialog window. . . . . . . . . . . . . . . . . . 93.8 IDL Visual Studio Merge Modules - welcome dialog window. . . . . . . . . . . 93.9 IDL Visual Studio Merge Modules - ready to install the program. . . . . . . . . 103.10 IDL Visual Studio Merge Modules - installing... . . . . . . . . . . . . . . . . . 103.11 Installation - destination directory dialog window. . . . . . . . . . . . . . . . . 113.12 RAMMS icon. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113.13 RAMMS program group. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113.14 RAMMS start window. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123.15 RAMMS licensing window. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123.16 Enter user name and company name. . . . . . . . . . . . . . . . . . . . . . . . 133.17 Personal license request file RAMMS_request_Muster Test.txt . . . . . . . . . 133.18 Personal license key file RAMMS_license_Muster Test.txt . . . . . . . . . . . 143.19 General tab of RAMMS preferences. . . . . . . . . . . . . . . . . . . . . . . . 153.20 Debris flow tab of RAMMS preferences. . . . . . . . . . . . . . . . . . . . . . 153.21 RAMMS preferences. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173.22 Browse for the correct folder. . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

4.1 The same project extent (area of interest) can be used to calculate differentscenarios with different input parameters. . . . . . . . . . . . . . . . . . . . . 19

4.2 Example ESRI ASCII grid. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204.3 Example ASCII X,Y,Z single space data. . . . . . . . . . . . . . . . . . . . . . 204.4 RAMMS Project Wizard: Step 1 of 4. . . . . . . . . . . . . . . . . . . . . . . 244.5 Step 1 of the RAMMS project wizard: Project information. . . . . . . . . . . . 254.6 Window to browse for a new project location. . . . . . . . . . . . . . . . . . . 254.7 Step 2 of the RAMMS project wizard: GIS information. . . . . . . . . . . . . . 25

i

List of Figures

4.8 Project coordinates: Lower left and upper right corner of project area. . . . . 264.9 Step 3 of the RAMMS project wizard: Project boundary coordinates. . . . . . 264.10 Step 4 of the RAMMS project wizard: Project summary. . . . . . . . . . . . . 264.11 Created project files. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 274.12 "Active" project with lines and corners for resizing . . . . . . . . . . . . . . . 284.13 "Active" project with rotation axes. . . . . . . . . . . . . . . . . . . . . . . . 294.14 3D view of example model. . . . . . . . . . . . . . . . . . . . . . . . . . . . 304.15 2D view of example model. . . . . . . . . . . . . . . . . . . . . . . . . . . . 304.16 The display tab. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 314.17 The colorbar properties window. . . . . . . . . . . . . . . . . . . . . . . . . . 314.18 Window to choose map image. . . . . . . . . . . . . . . . . . . . . . . . . . . 324.19 About RAMMS... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 354.20 Project with emerging release area. . . . . . . . . . . . . . . . . . . . . . . . . 374.21 Release area and volume information. . . . . . . . . . . . . . . . . . . . . . . 384.22 Release area information window. . . . . . . . . . . . . . . . . . . . . . . . . . 394.23 Three-point hydrograph with total volume of debris flow. . . . . . . . . . . . . 404.24 Four-point hydrograph for discharge values of an event, August 2, 2005, at

Illgraben, Valais, Switzerland. . . . . . . . . . . . . . . . . . . . . . . . . . . . 414.25 Comparison of a three-point with a four-point hydrograph for the given dis-

charge data with the same total volume. . . . . . . . . . . . . . . . . . . . . . 414.26 Definition of inflow direction of an input hydrograph. . . . . . . . . . . . . . . 424.27 Line release area for the input hydrograph inside the calculation domain. . . . . 434.28 Release height required only for hydrograph location. . . . . . . . . . . . . . . 434.29 Calculation domain in green encloses the area of interest and reduces calculation

time in comparison with the default rectangular domain which is automaticallygenerated. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

4.30 General information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 454.31 Calculation parameters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 464.32 Friction values. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 474.33 Release information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 474.34 Stop criteria. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 484.35 Status window of calculation. . . . . . . . . . . . . . . . . . . . . . . . . . . . 494.36 Main window in output mode. . . . . . . . . . . . . . . . . . . . . . . . . . . 504.37 Outflow volume alert. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 504.38 Output Logfile. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 514.39 RAMMS Project Input Log file. . . . . . . . . . . . . . . . . . . . . . . . . . . 524.40 Region extent (X-, Y- and Z-Coordinates, total area). . . . . . . . . . . . . . . 52

ii RAMMS User Manual

List of Figures

4.41 Results: Maximum values of flow height (left), velocity (middle) and pressure(right). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

4.42 Quasi 3D-Visualization of flow height (left: exaggeration 1; right: exaggeration5) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

4.43 Line profile plot. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

4.44 Line profile perpendicular to debris flow direction. . . . . . . . . . . . . . . . 57

4.45 Line profile along the debris flow path. . . . . . . . . . . . . . . . . . . . . . 57

4.46 Time plot window. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

4.47 Summary of moving mass. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

4.48 Stopping behavior of a RAMMS simulation. Small threshold values may leadto unlikely slow creeping of the material. In the example shown in the figureabove the stopping criteria is set to 0%. . . . . . . . . . . . . . . . . . . . . . 62

4.49 Stopping behavior of a hydrograph RAMMS simulation. In this example thresh-old values <5% lead to numerical diffusion of the simulation results. A thresh-old value of 5% seems to be appropriate in this case. . . . . . . . . . . . . . . 63

4.50 Stopping behavior of a block release RAMMS simulation. In this examplethreshold values <2% lead to numerical diffusion of the simulation results.Threshold values of 2-3% seem to be appropriate in this case. . . . . . . . . . 63

4.51 Numerical instabilities. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

4.52 Smoothed terrain (e.g. mean 5x5 filter in Arc GIS). . . . . . . . . . . . . . . . 65

4.53 Solutions to numerical instability problems. . . . . . . . . . . . . . . . . . . . 65

4.54 Release area where a dam is supposed to be built. . . . . . . . . . . . . . . . . 67

4.55 Dam. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

4.56 Simulation without mitigation measures. . . . . . . . . . . . . . . . . . . . . . 68

4.57 Simulation with two dams built in RAMMS . . . . . . . . . . . . . . . . . . . 68

4.58 Comparison of the profiles of two mitigations measures in RAMMS . . . . . . . 68

4.59 Dam with gradually rising side walls. . . . . . . . . . . . . . . . . . . . . . . . 69

5.1 Simulations with best-fit parameters µ=0.225 and ξ=130 m/s2 for (a) a volumeof 10’000 and (b) 5’000 m3 and a DEM resolution of 2 m. The dashed lineindicates the flow path of the event from June 7, 2010. . . . . . . . . . . . . . 74

5.2 Comparision of discharge curves of a simulation with a block release and ahydrograph for (a) a volume of 200’000 m3 and (b) a volume of 2’250 m3. Forall simulations µ=0.225 and ξ=130 m/s2. The discharge curves are measuredat the location shown in Fig. 5.3. . . . . . . . . . . . . . . . . . . . . . . . . . 77

WSL Institute for Snow and Avalanche Research SLF iii

List of Figures

5.3 Comparison of the inundated areas of a simulation with a block release anda hydrograph (a) for a volume of 200’000 m3 and (b) a volume of 2’250 m3.For all simulations µ=0.225 and ξ=130 m/s2. Blue: hydrograph, red: blockrelease. The red points indicate the location of the measured discharge curves(Fig. 5.2). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

5.4 The release area (27’900 m2) (red area) was located in the lower reach ofthe active debris flow catchment and the digital terrain model DTM AV byswisstopo with 2 m grid size was used for the simulations. Density of the debrisflow mixture was set at 2’000 kg/m3 (typical value for the Illgraben). Thelocation of the line profiles at the apex of the fan and the lower third of thefan (check dam 27) are indicated with red lines. . . . . . . . . . . . . . . . . . 81

5.5 (a) Simulations with best-fit parameters µ=0.07 and ξ=400 m/s2 for a vol-ume of 50’000 m3. (b) Profile where spill over was observed (profile locationindicated by red line in (a)). . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

5.6 Lambda=1.0 and Lambda=2.5 for a block release. . . . . . . . . . . . . . . . 855.7 Lambda=1.0 and Lambda=2.5 for a hydrograph release. . . . . . . . . . . . . 85

6.1 Graphical user interface (GUI). . . . . . . . . . . . . . . . . . . . . . . . . . . 876.2 The active time step (139) is shown in the time step slider. . . . . . . . . . . . 986.3 Status information shown in the left status bar. . . . . . . . . . . . . . . . . . 986.4 Position information and triangle simulation results in the right status bar. . . . 986.5 Colorbar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 996.6 Debris flow panel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1006.7 No transparency (left) and 40% transparency (right) of simulation result. . . . 101

iv RAMMS User Manual

List of Exercises

3.6.a: Working directory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

4.3.a: How to create a new project. . . . . . . . . . . . . . . . . . . . . . . . . . . 24

4.4.a: Moving and resizing the model . . . . . . . . . . . . . . . . . . . . . . . . . 28

4.4.b: Rotating the model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

4.4.c: How to switch between 2D and 3D mode . . . . . . . . . . . . . . . . . . . . 30

4.4.d: Editing the colorbar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

4.4.e: How to add or change maps. . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

4.4.f: How to add or change remote sensing imagery. . . . . . . . . . . . . . . . . . 32

4.4.g: How to save input files and program settings manually. . . . . . . . . . . . . 33

4.4.h: How to open an input file. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

4.4.i: How to open an output file/simulation. . . . . . . . . . . . . . . . . . . . . . 34

4.4.j: How to load an optional shapefile. . . . . . . . . . . . . . . . . . . . . . . . . 34

4.5.a: How to create a new release area. . . . . . . . . . . . . . . . . . . . . . . . . 37

4.5.b: How to load an existing release area. . . . . . . . . . . . . . . . . . . . . . . 38

4.5.c: Specify release height and view release information . . . . . . . . . . . . . . . 39

4.5.d: How to use the input hydroraph. . . . . . . . . . . . . . . . . . . . . . . . . 43

4.5.e: How to run a calculation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

4.6.a: Displaying max values. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

4.6.b: How to draw a line profile. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

4.6.c: How to create a time plot. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

4.7.a: How to create a new DEM to simulate a dam. . . . . . . . . . . . . . . . . . 67

4.7.b: How to add debris flow deposition to a new DEM. . . . . . . . . . . . . . . . 70

v

Index

BackupBackup Active Project, 88Backup RAMMS Version, 88Backup User-Defined Files/Folders, 88

Block Release, 21, 76, 79Example, 79

Calculation Domain, 44Draw New Calculation Domain, 44, 89Load Existing Calculation Domain, 44,

89Calibration, 71Colorbar, 99

Edit Colorbar, 31

Dam, 67, 70Add Dam To DEM, 67, 92

Debris FlowBlock Release, 21Channelized, 21, 79Hydrograph, 21, 40Unchannelized, 21

DEMAdd Dam To DEM, 67, 92Create New DEM, 67, 70Set DEM Directory, 15

Disclaimer, 2

Earth-Pressure, 84Active, 84Lambda, 84Passive, 84

EditEdit Dataspace Properties, 89

Example, 76, 79Block Release, 79Illgraben, 79Input Hydrograph, 76

Exit, 88Export

Export Display To Image File, 88Export GIF Animation, 88Export Result To Google Earth, 93Export Results As ASCII Grid, 92Export Results As Shapefile, 92

File*.tfw, 32GIF, 60World, 32

File Management, 102Flow Height, 53, 91

Max Flow Height, 53, 91Flow Momentum, 53, 91

Max Flow Momentum, 53, 91Flow Pressure, 53, 91

Max Flow Pressure, 53, 91Flow Velocity, 53, 91

Max Flow Velocity, 53, 91Forest

Set Forest Directory, 15Friction Parameter, 22, 91

µ, 91

vii

List of Exercises

ξ, 91Calibration, 23, 71Physical Friction Model, 22

GIF Animation, 60Graphical User Interface, 87

Colorbar, 87Main Window, 87Menu Bar, 88Edit, 89Extras, 93GIS/GRASS, 92Help, 94Input, 89Project, 94Results, 91Run, 90Show, 90Track, 88

Panel, 87Status Bar, 87Time Step Slider, 87Toolbar Buttons, 87

Hydrograph, 21, 40, 76

ImageAdd/Change Image, 32, 93Load New Image, 32Set Orthophoto Directory, 15

Impact Pressure, 86Input

Input File, 93Model Input Data, 20

Input Hydrograph, 21, 40, 76Example, 76

Installation, 5

Licensing Methods, 12Load

Load Existing Domain, 89Load Existing Release Area, 36, 38, 89Load New Image, 32Load New Map, 32Load Release File, 38Load Shapefile, 34

LogfileRAMMS Logfile (Current), 88RAMMS Logfile (Last Session), 88

Main Window, 98Map

Add/Change Map, 32, 93Load New Map, 32Set Map directory, 15

Move, 28

Numerical Instabilities, 64

OpenOpen Input File, 34Open Output File, 34Open Shapefile, 34

OrthophotoAdd/Change Image, 32, 93Load New Image, 32

Panel, 100Debris Flow PanelDisplay, 100General, 100Region, 100Transparency, 101Volumes, 100

Point, 93Preferences, 15, 17, 88

Set DEM Directory, 15Set Forest Directory, 15Set Map directory, 15Set Orthophoto Directory, 15

viii RAMMS User Manual

Index

Set Working Directory, 15, 17Pressure, 86Profile, 93Project

Create new Project, 24Model Input Data, 20Preparations, 19Project Information, 51Project Wizard, 24Scenarios, 19Wizard, 24

Publications, 107

RAMMS Logfile (Current), 88RAMMS Logfile (Last Session), 88References, 105Release Area, 36

Create Manually, 36, 44Crop Release Areas, 89Draw New Release Area, 89Load Existing Release Area, 36, 38, 89Release Information, 39Shapefile, 36View/Edit Release Area, 89

Release Information, 21Reload Position, 93Resize, 28Results, 53

Flow Height, 53Flow Momentum, 53Flow Pressure, 53Flow Velocity, 53Line Profile, 53, 60Max Values, 53, 54Time Plot, 54, 60

Run CalculationCalculation Domain, 44Constant, 45Scenario, 36

SaveSave Active Position, 93Save Automatically, 33, 34Save Manually, 33

Shapefile, 36Convert Shapefile, 92Export Results As Shapefile, 92Import GIS Polygon Shapefile, 92Load Shapefile, 34Open Shapefile, 34

ShowShow Contour Plot, 92Show Curvature, 92Show Slope Angle, 92

Status BarLeft, 98Right, 98

Stop, 61Summary Of Moving Mass, 61

Structures, 66Summary Of Moving Mass, 61System Requirements, 5

Time Step Slider, 98Toolbar

Horizontal, 95Vertical, 97

Transparency, 101

Update, 14

WSL Institute for Snow and Avalanche Research SLF ix

rapid mass movements simulation RAMMS

WSL Institut für Schnee- und Lawinenforschung SLFWSL Institut pour l‘étude de la neige et des avalanches SLFWSL Instituto per lo studio della neve e delle valange SLFWSL Institute for Snow and Avalanche Research SLF

RAMMS Debris Flow Modelling Manual

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