E3S Web of Conferences 415, 07002 (2023)
DFHM8

https://doi.org/10.1051/e3sconf/202341507002

MurGame: Protect your village from debris flows!
Catherine Berger1*, Florian Zimmermann1, Ralf Mauerhofer2, and Marc Christen3
1geo7 AG, Neufeldstrasse 5 – 9, 3012 Bern, Switzerland
2Koboldgames GmbH, Technopark Aargau, Badenerstrasse 13, 5200 Brugg AG, Switzerland
3WSL-Institute for snow and avalanche research SLF, Flüelastrasse 11, 7260 Davos Dorf, Switzerland

Abstract. Past debris flow events, like in Bondo (2017) and Brienz (2005) in Switzerland have been heavily
covered in the (Swiss) media, illustrating how destructive such events can get. Protection measures play animportant role in dealing with natural hazards. Debris flows are considered to be very rare, complex andmultidimensional processes. Imagining and foreseeing the course and progression of a debris flow as wellas estimating the potential damage and the influence of protection measures is a difficult task. Serious games
offer a possibility to simulate these kinds of situations. With the MurGame, we have developed an
application for natural hazard prevention. In the three-dimensional, interactive game, a village is created byselecting different objects, such as residential buildings or schools. Debris flow simulations show, whichbuildings would be destroyed and what damage would occur in the event of a debris flow. Different
protection measures can be implemented to protect the village and their effectiveness can be monitored
during the simulations. After the event, it is necessary to evaluate which measures offer the desired
protection, what they may cost and how the needs of the population are met. The MurGame can be playedonline at www.murgame.ch.

1 Introduction
Raising the public awareness of natural hazards, theirdestructive forces as well as ways to prevent damage is an
essential element of the integrated risk management
system. In order to achieve this goal, it is crucial tomaintain a well-balanced, target group-orientedcommunication. New means of communication, such asserious games, make it possible to address additionaltarget groups or to convey scientific content in an
innovative way. The MurGame is an interactive 3D gamefocusing on hazard prevention and raising risk awareness.
It breaks new ground in communicating and presenting
the contents of the integrated risk management system fornatural hazards within the setting of a serious game. The
aim of the interactive game is to reduce the damage
caused by debris flows by means of various measures,
while taking into account the needs of the population as
well as the cost-effectiveness (cost-benefit ratio) of themeasures. As a server-based web game that is flexible interms of time and location, the MurGame can be used foreducation, at events or integrated into a website. The
MurGame is available in English, German, French and
Italian and can be played online at www.murgame.ch.

2 Overview of the MurGame
The first step of the game includes the construction of afictional village. Dwelling houses, a school, barns,
bridges or a campsite can be placed in order to fulfil anumber of tasks (Fig. 1). As the number of dwellings
increases, so does the number of inhabitants.
Building costs are continuously added up and theacceptance among the population changes depending on
the built objects. The simulation of a small or large debris
flow can be started, as soon as the minimal tasks arecompleted and the village is set up. After a debris flow
event, the damage report provides information on
construction costs, damage caused and acceptance by thepopulation in respect to the village infrastructure.

Fig. 1. Overview impressions MurGame. A village is built on
the alluvial fan (top right) which is then severely damaged by adebris flow (bottom left) and protected by a dam / dyke(bottom right).

The next step consists of finding ways to protect thevillage from future debris flows. Structural protection
measures in and around the village such as dams / dykes
and debris flow barriers, as well as organisational* Catherine Berger: murgame@geo7.ch© The Authors, published by EDP Sciences. This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0(https://creativecommons.org/licenses/by/4.0/).

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3.1 Debris flow modelling

protection measures can be set up. Existing buildings may
be relocated (Fig. 2, top).
A second debris flow can be simulated as soon asprotection measures are placed and consideredsatisfactory. The updated damage report allows the player
to assess the effects of the protection measures, theirconstruction costs, the damage caused or prevented andthe acceptance of the measures by the population. Inaddition, the cost-effectiveness (cost-benefit ratio) of theprotection measures is calculated (Fig. 2, bottom).

The
MurGameuses
thesimulation
model
RAMMS::DEBRISFLOW [5] to represent the debris flow
and the damage calculation based on it.
RAMMS::DEBRISFLOW is a numerical model
developed at the WSL Institute for Snow and Avalanche
Research SLF. The simulation model is based on theVoellmy model using two friction parameters. Flow
depths and velocities are calculated on 3D digital terrain
models (DTM) by using an efficient 2nd order numericalsolution of the depth-averaged equations of motion [6].
For the MurGame, two realistic debris flow scenarios
were assessed for the torrent. Debris flow volumes are
10,000 m3 for the large and 5,000 m3 for the small debris
flow. An input hydrograph with peak discharge at
150 m3/s for the large and 100 m3/s for the small debris
flow was defined. Friction parameters were set at μ = 0.25
and ξ = 200 m/s2. For the check dam and retention net, aretention volume of 5,000 m3 is assumed. Therefore, forthe scenario “small debris flow with check dam / net”, theentire debris flow is retained. For the scenario “largedebris flow with check dam / net”, the debris flow with5,000 m3 volume is considered.
Large objects (church, school, farm) as well as robust
structural measures (dams / dykes, concrete walls,retention structures) influence the flow path of a debrisflow. These elements are considered in the simulations
and lead to a protective effect behind dams / dykes, forexample. Small objects (residential buildings, shops,stables, garages) and in-effective measures such as
sandbags do not significantly influence the course of adebris flow. Therefore, they are not taken into account in
the simulations.
A differentiation was made regarding bridges: The
bridge close to the river outlet and the “small bridge” inthe middle of the fan are considered as insufficient incapacity and were integrated into the DEM as an obstaclein the torrent. However, the capacity of the large bridge isassumed to be sufficient and this bridge is not taken into
account as an obstacle and is neglected in the simulations.
Debris flows for every possible combination of objects
and measures have been pre-simulated and are available
at stock. Depending on the village design, thecorresponding simulation is loaded, visualised and used
for the damage calculation. A total of approx. 1,200
simulations were pre-simulated for the MurGame.

Fig. 2. Debris flow event through a protected village in the
MurGame (top). The updated damage report compares theunprotected village (bottom right) to the protected village(bottom left).

The damage reports of the different village designs
can be compared with each other to find an optimalbalance between minimal damage, reasonable
construction costs and a sufficient acceptance of theprotection measures within the population (Fig. 2).
However, as in reality, it will not be possible to achieve
an absolute protection against natural hazards and still becost-effective at the same time. Therefore, the player mustfind the best possible balance between the degree ofprotection, the costs of implementing the protection
measures and the residual risk.

3.2 Loss calculation
Basically, damage occurs when a hazard process hits anobject. The extent of the damage depends on the type andvalue of the object as well as the natural hazard process
and the intensity of the process. In Switzerland, thedetailed calculation of the risk to settlement areas andinfrastructure facilities from the threat of natural hazards
is carried out according to the EconoMe methodology [1].
This forms the basis for the integrated risk management
system and thus the handling of natural hazards. In theMurGame, damage is calculated according to theapproaches used in practice in Switzerland [1], [2], [4](see publication [7] for a summary in English).

3 Background information
The MurGame is set in a fictional environment. A typicaltorrent flows from a steep catchment area to a larger riveron the valley floor. On the alluvial fan of the torrent, there
is a settlement with a main access road running along theriver in the valley floor. The elevation model (cell size2 m) used for the MurGame is taken from a real torrent
catchment and was prepared for use in the game.

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3.3 Key performance indicators

In a first step, the debris flow intensity is determinedin the corresponding village setting per existing object androad section as a function of the respective flow depth atthe object or road from the corresponding
RAMMS::DEBRISFLOW simulation. For simplification,
flow velocity was neglected and 3 classes of intensity
were assigned from maximum flow depth: low (0 –0.3 m), medium (0.3 – 1 m) and high intensity (> 1 m).
Based on this intensity, the parameters for the personal
injury and property damage calculation are derived. The
spatial probability of occurrence is assumed to be 100 %,as the debris flow simulations represent discrete processareas. Recurrence periods were set at 100 years for thesmall and 300 years for the large debris flow.
The damage calculation in the MurGame takes into
account personal injury and property damage for objects
and roads according to EconoMe [1] as well as supply
damage due to the interruption of traffic routes according
to the approach of the Canton of Zurich, Switzerland [4].
The personal injury and property damage (probableextent of damage) are determined according to themethodology by EconoMe [3]. Furthermore, the values
for the respective objects according to EconoMe [1] wereused for the parameter vulnerability and lethality. For thebasic values of the buildings, reference values of theSwiss insurance industry (Vereinigung Kantonaler
Gebäudeversicherungen VKG, Mobiliar) were used. The
movable property was added to the tangible value by asurcharge of 20 %. The costs of measures could bederived from empirical values for construction projects.
In the game, typical values for Switzerland were usedand currency is Swiss franc CHF. The monetization ofinjured / death people is calculated using the value of astatistical life. This value is set at CHF 6.6 million
according to EconoMe [1]. Further parameters forbuildings (number of occupancies and presence
probability factors) and road traffic (speeds, values foraverage daily traffic and number of average journeys)
were specified to the setting in the MurGame.
For reinforced construction, elevated windows /entrances and elevated arrangement, probable extent ofdamage of the specific object is reduced by 100%, 80%
and 50% for low, medium, and large debris flow intensity
respectively. For organizational measures, probable
extent of damage is reduced by 20% for siren andemergency planning, and by 5% for using an informationbulletin. If the gate is installed, probable extent of damageon the main road between the barrier is reduced by 100%.
The calculation of the supply damage is based on themethodology of the risk analysis of the Canton of Zurich,
Switzerland [4]. This approach is based on a qualitative
determination of the risk for the interruption of trafficroutes (municipal, main road and bridge). As soon as adebris flow buries a section of a road, a corresponding
damage due to the interruption of supply is calculated. Adistinction was made between the smaller roads on the fan
and the main access road. For a better comparison withthe other damages, the qualitative values were monetized(marginal costs 500'000 CHF).

In addition to the key performance indicators damage andcost-effectiveness, a third element called “acceptance”
was introduced to the game in order to design a wellbalanced challenge to the game. In the damage report,
acceptance among the population for the specific village
consists of the individual evaluations for the selectedbuildings, bridges, structural and organisational
protection measures. The values of acceptance for theseobjects were assessed subjectively and range from 0 to 10.
The acceptance of a village equals to the average of theindividual values.
In the damage report, key performance indicators
were classified. For damage, classes were- 1* with damage > 20 million CHF- 2* with damage between 20 and 8 million CHF- 3* with damage between 8 and 1.5 million CHF- 4* with damage between 1.5 million and400,0000 CHF- 5* with damage < 400,000 CHF
For cost-effectiveness, a linear interpolation was applied
between the minimum value of 0 (equals to 1*) andmaximum value of 12 (equals to 5*).
For acceptance, a linear interpolation was applied
between the minimum value of 3 (equals to 1*) andmaximum value of 8 (equals to 5*).

4 Simplifications / gaming assignments
In order to visualise the topic of integral risk management
in a clear and informative way, a number ofsimplifications have been made and certain aspects of therisk assessment have been excluded.
Basically, the term risk is understood as the possibility
that damage may occur as a result of a certain event. In
the context of natural hazards, the risk is composed of thefrequency or return period of several events and thepossible extent of damage (persons and property). In
Switzerland, the collective and the individual risk areconsidered for the assessment of the risk [2], [7]. The risk
concept consists of three elements: risk analysis, risk
assessment and risk management. An important basis forthis are the hazard and intensity maps that exist
throughout Switzerland in the vicinity of settlements. The
calculated risk is assessed as part of the risk evaluation
and, if necessary, measures are taken. However, even after
protection measures have been taken, there is still a
residual risk, as absolute safety from natural hazards
cannot be achieved in a hazard-prone area.
A variety of different systems can be used for theimplementation of protection measures. However, aspects
such as additional hazards or the shifting of hazards andlegal requirements such as ecology and the costeffectiveness of the measures must be considered.
Furthermore, the possibilities for protection measures areoften limited due to spatial, social and economic
framework conditions. All these aspects were notincluded in the MurGame. However, depending on thetype of application and moderation, these points can beaddressed. Depending on the target audience, different

3E3S Web of Conferences 415, 07002 (2023)
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emphasis can be given, especially in the context ofeducation and training events. Single aspects of risk
management, such as cost-effectiveness or damage
minimisation can be addressed. More complexity can beadded by focusing on several aspects simultaneously (e.g.,damage, cost-effectiveness and acceptance) or on specifictopics such as economy by limiting the available budget
for construction measures or vulnerability by assessing
the impact of the different bridges on the hazard situation.

5.
6.

5 Conclusion

7.

The MurGame teaches various aspects of the integrated
risk management system by focusing on hazard
prevention and raising risk awareness through theexample of the debris flow hazard process. If a debris flow
occurs, human lives, buildings and infrastructure facilities
are threatened. The aim of the interactive 3D game is toreduce the possible damage caused by debris flows bymeans of various structural and organisational measuresand spatial planning, while obtaining the best possible
cost-benefit assessment. In order to achieve this goal, theMurGamer has to fulfil a minimal number of tasks, which
include the expansion of the village as well as theimplementation of effective protection measures. A focus
should be given to the cost-effectiveness (cost-benefitratio) of the measures. Therefore, it is crucial to achieve
an optimal balance between the prevented damage and theconstruction costs. Besides the cost-benefit considerations
the success of protection measures will also be dependent
on the acceptance of the measures by the village
population. All these aspects must be coordinated in order
to best protect the village that has been built.
The MurGame (Version 2.0) was developed by geo7 AG,
Koboldgames GmbH and WSL-Institute for Snow andAvalanche Research SLF. Special thanks goes to the funders
Vereinigung Kantonaler Gebäudeversicherungen VKG(Switzerland), la Mobilière (Switzerland) and the Federal Officefor the Environment FOEN of Switzerland. Translation of the
MurGame to English was supported by Geobrugg AG and toItalian by the Republic and Canton of Ticino andGebäudeversicherung Graubünden GVG.

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