workshop on flood maps - umwelt in sachsen workshop on flood maps 21.-22.09.2006 berlin -...

Expert Workshop on Flood Maps 21.-22.09.2006 Berlin - Umweltforum Report

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Saxon State Agency for Environment and Geology

IR III C LOGO

The project i spart financed by the European Regional Development Fund in the programme INTERREG III C


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Responsible project partner

Saxon State Agency For Environment And Geology Section 35 - State Flood Center - P.O. Box 80 01 32, 01101 Dresden Zur Wetterwarte 11, D-01109 Dresden Internet: http://www.umwelt.sachsen.de/lfug

Contact :

André Freiwald Mail: [email protected] Phone: ++49351/ 8928 228; Fax: ++49351/ 8928 245 Editors of the report: • Oliver Gretschel (INFRASTRUKTUR & UMWELT, Potsdam) • Peter Heiland (INFRSTRUKTUR & UMWELT, Darmstadt) • André Freiwald (LfUG, Dresden) With contributions of

• Jürgen Neumüller (INFRASTRUKTUR & UMWELT, Potsdam) • Ivo Leiss, Ernst Baseler & Partner, Zürich • Peter Zeisler, Rodriguez + Zeisler + Blank, Wiesbaden • André Assmann geomer GmbH, Heidelberg • Manuela Gretschel, University of applied sciences Magdeburg-Stendal • Kees de Gooijer, HKV Consultants, Lelystad, the Netherlands • Frédérique Martini, Ministère de l’écologie et du developpement durable, Paris, France processed by:

Darmstadt / Potsdam Dresden / Darmstadt / Potsdam, October 2006

Saxon State Agency for Environment and Geology


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1... Preface 1 2 Goals and outline of the Workshop 1 3 Flood Mapping: Demands and Framework 3

3.1 Terminology and map types 3 3.1.1 Flood map types, Hazard maps, Risk maps, Hazard indication maps....................3 3.1.2 The draft of the flood directive and relevance for flood mapping ............................6 3.1.3 Transnational projects that aim flood mapping (overview) ......................................7

3.2 User groups and different demands of the user groups 8 3.2.1 Regional spatial planning.........................................................................................9 3.2.2 Local land use planning...........................................................................................9 3.2.3 Civil defence / emergency management ...............................................................10 3.2.4 Water management / flood protection agencies....................................................10 3.2.5 Storage of potential pollutants ...............................................................................10 3.2.6 Insurances .............................................................................................................11 3.2.7 Conclusions for the definition of demands.............................................................11

3.3 The framework of the planning systems 11 4 Presentations of the Workshop 14

4.1 Process of Flood mapping – examples from the „Oder Flood hazard maps“ (OderRegio project) 14 4.2 Practice examples from different rivers 18

4.2.1 Cross border flood hazard maps - Experiences from the TIMIS flood project ......18 4.2.2 Flood maps for the cross border cities of Görlitz (D) and Zgorzelec (PL) .............20 4.2.3 Experiences from the Rhine-/Elbe-Atlas................................................................21

4.3 Use of flood maps for flood management 23 4.3.1 Hazard Maps for Stendal County in Saxony-Anhalt ..............................................23 4.3.2 FLIWAS and flood maps........................................................................................26 4.3.3 European exchange circle on flood mapping - EXCIMAP.....................................27

5 Discussion and Results 28 5.1 Definition of maps: users; science, demands 28 5.2 Processing of maps 30 5.3 Policy relevance 33

6 Conclusions for the FLAPP Policy Working GroupFout! Bladwijzer niet gedefinieerd. 7 Conclusions regarding the EXIMAP Project 34 8 Outlook 36


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1 Preface Within the framework of INTERREG III C cooperation project FLAPP (Flood awareness and prevention policy) a workshop on flood maps has been organized by the Saxon State Agency for Environment and Geology (Dresden). The workshop took place in Berlin on 21st and 22nd September 2006. It was part of the component C3 (flood prevention) activities. The workshop was open for FLAPP project partners and for other experts in the issues of flood hazard mapping and spatial planning (see annex “participants”).

The aim of the workshop was:

- to inform the interested FLAPP partners about flood mapping, techniques and recent developments in Europe,

- to discuss obstacles and challenges in cross border flood mapping,

- to discuss technical and communicative aspects of the visualization of flood maps and

- to provide input for the FLAPP policy working group and the EXCIMAP-Initiative.

About 20 participants presented and discussed in 2 days many examples and experiences of flood mapping from different regions in Europe. The workshop was very lively in the discussions and delivered many new insights into the practice of flood mapping. A very special opportunity of the workshop was to reflect the latest draft on the European flood directive (from June 2006) which will be the framework for flood mapping in the next decade.

This report documents the presentations and the discussions as well as the results of the workshop. It contains a chapter with an overview about flood mapping approaches in Europe and the legal background. The presentations of different participants showing examples of flood mapping activities are reflected in short summaries in the fourth chapter. Nevertheless the full presentations can be seen on the CD-Rom in the annex of the report. Finally the “result chapters” summarize the discussions and the outcome of the writing sessions. In addition to this documentation 2 chapters focus on conclusions of the workshop for the FLAPP policy working group on one side and for the EXCIMAP project on the other. These 2 chapters have been added by the editors of the report to filter those recommendations or conclusions that can be used for follow-up activities in the other projects.

In the annexes the organizational parts of the workshop and an overview about the presentations can be found.

2 Goals and outline of the Workshop Besides the goals that were set by the organizers and the FLAPP partner group the participants were asked which goals they have individually for the workshop. Here it became very clear that 3 major goals exist among the participants:

- to learn individually about other examples and methods than known by the experts themselves,

- to reflect the present discussion about the flood directive in the discussions and in the examples that are presented,

- to produce an outcome for the FLAPP policy working group and for the EXCIMAP Project.

The following table shows in a comprehensive way the questions that have been asked to the presenters and to the working groups throughout the workshop.


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Theme A: Definition of maps: users, science, demands Key words General questions Specific questions (“cross border …”) User groups - General Public - Spatial Planning (local, regional) - Emergency management - Water management (flood protection) - Insurances

1. Are user groups generally defined or very specific?

2. Which are most relevant user groups in the examples?

3. How were the users integrated into the process?

a. Which users are specifically important in cross border river basins?

b. How where the users of both sides of the border involved?

c. Were there any problems in communication?

d. Were there problems due to different expectations/ objectives of the counterparts?

Demands of the user groups - Scale - Scenarios - Flooded area / water depth - Hazards or risks (damage) - Forecast features - Accuracy - further demands

4. Which were the specific demands of the user groups?

5. Which information in the map are user-specific?

6. Which demands were especially subject of discussion in the examples?

7. Which demands should apply - generally - for special situations / users

a. Which demands are specific for cross border river basins?

b. Which demands are special obstacles for cross-border river flood mapping?

Demands of policies - EU flood directive - National policies - others

8. Which of the demands of the EU directive (draft) are fulfilled (not fulfilled) in the exemplary approaches?

9. Open questions regarding the EU directive (draft)?

10. Which specific national policies are significant for the examples?

a. What were the administrative or institutional obstacles for the flood mapping process?

b. Which policies - help - hinder the process of cross-border flood mapping?

c. Why? Obstacles? Demands of Science - basic principles/ concepts - Uncertainty (climate, others) - Models - Parameters / Accuracy (velocity, depth, damage functions, etc.), relevant discharge

11. How have the discharges/ flows been determined, especially for the extreme event?

12. Which parameters have been considered (e.g. climate change, type of floods?)

13. How are the uncertainties communicated?

a. Were there differences in the concepts or approaches among the counterparts that caused problems?

b. How were these problems solved?

Theme B: Processing of maps Key words General questions Specific questions (“cross border …”) - Hydraulic issues - Hydraulic modelling /

Scenarios - GIS processing - Costs of map processing

14. Which models have been used in the examples?

15. Which scenarios have been developed?

16. Which GIS systems have been used?

17. What did the hazard maps cost (estimation in Euro per Km)? - conditions for the costs? - special arrangements the lower the costs?

a. Which technical issues were specifically difficult in the cross-border mapping project?

b. What did you do to overcome the problems?

c. Good practice examples?


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Theme C: Dissemination and maintenance Key words General questions Specific questions (“cross border …”) - Accessibility of maps - Format / design - Legal aspects - Documentation, manuals - Guidelines for the use - Education / training activities

18. How are the maps presented and used? (different possibilities)

19. Which problems appeared? (solutions)

20. Are manuals, guidelines and training sessions offered to the users?

21. What is done to keep the maps up to date?

a. Are the specific demands, obstacles or chances for the dissemination of the flood maps in cross border projects?

b. Good practice examples?

The outline of the workshop has three different blocks:

- presentations of overviews and examples for cross border activities in flood mapping in Europe and discussions about these presentations

- examples from the use of flood maps in flood hazard management systems and related discussions

- a writing session to discuss conclusions and to write down the recommendations and open questions.

The program is shown in the annex of this report.

3 Flood Mapping: Demands and Framework PETER HEILAND INFRASTRUKTUR & UMWELT, PROF. BÖHM UND PARTNER, DARMSTADT

3.1 Terminology and map types

3.1.1 Flood map types, Hazard maps, Risk maps, Hazard indication maps The terminology in flood mapping has not been harmonized in Europe yet. Due to the fact that many different conditions exist in different regions, also different approaches have been developed, with different terms. Even more, some terms are not clearly defined. Thus, in the following, as starting point for the workshop and for the report, some more or less generally accepted terminologies are explained.

Flood hazard maps

Hazard maps show where flood events occur. There are different informations which should be shown in hazard maps, like extend of potential flood areas, water depth etc.

Definition of hazard maps: Hazard maps show the danger of flooding as result of the coincidence of probability and intensity. They should be produced for all areas in which flood damage could occur. Intensity often is simplified by water-depth. An alternative is to show velocity as indicator for intensity (LAWA 2006, draft).

Flood hazard zoning maps show categories of hazard levels (probability and intensity). They are the link between water management tools and zoning instruments of spatial planning.


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Flood hazard indication maps have been defined by the Swiss Federal Office for Water and Geology (BUWAL 1997)as overview maps, that indicate in an overview scale where flood hazards could occur without an assessment of single locations. They indicate where flood problems should be taken into consideration and where to assess the situation before planning any other use.

Figure: Flood hazard maps, example Baden-Württemberg (from …. Xxxx)

Figure: French flood hazard indication map (overview map); from …..xxxx

Water depth (HQ 100, with protection and HQ Extrem)

Innundation for diff. Scenarios (HQ 50, HQ 100, with protection and HQ extreme)


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Local flood information maps

Local flood information maps are focusing on the local planning issues. There are maps for civil protection, for protection works and maps for insurance purposes. Local flood information maps have local planning scales of 1:5.000 to 1:20.000.

Flood risk maps

Risk maps are maps show potential consequences of flood events by combining hazard information and vulnerability (damage potential). Usually categories of risk are shown for risk areas (acc. to Merz et al. 2005, extended with the EU flood directive etc.).

The risk is quantified by means of - potentially affected people - potentially affected values or - industrial activity etc.

It should also include potential environmental damage, etc.;

One central question is, how to show the indicators for risk in a map. One example is the damage potential which is shown in the Rhine-atlas as a separate map.

In general the following major characteristics have been structures in the INTERREG IIC IRMA SPONGE project no. 5 (Böhm, Heiland, Dapp, 2001) based on the guidelines of the Swiss federal office for Water and Geology (FOWG 1997):

Overview map

Hazard-index map (H. indication maps)

Hazard map

Scale 1:100.000 – 1:1.000.000 1:10.000 – 1:100.000 1:2.000 – 1:10.000 Aim Overview map on

national or supraregional level (transboundry

rivers)

Identify and localize the hazards

Basis for regional planningRough detection

of conflict of interests

Analyse and assess the hazards

Basis for local planning Basis for planning of

precautionary measures Content Overview of threat to

individual regions or municipalities

Overview of threat to individual parts of

municipalities. Maybe subdivision into

several degrees of danger

Detailed information on type, extent and degree of

hazards Detailed documentation is

necessary

Accuracy Very low Low High – building lot sharp limitation

Covered areas

Transnational areas, Countries, Regions

Regions (developed and undeveloped areas)

Focus on existing or planned settlement areas

and on infrastructure (highways)

Target group

Spatial planning Policy

Regional planning Water management

Policy Reinsurance companies

General public

Local and urban land-use planning

Local policy Insurance companies Emergency planning Affected population


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3.1.2 The draft of the flood directive and relevance for flood mapping

The latest draft of the flood directive is from 26th June 2006. It is structured with the following chapters:

• Chapter I: General provsions

• Chapter II: Preliminary flood risk assessment

• Chapter III: Flood hazard maps and flood risk maps

• Chapter IV: Flood risk management plans

• Chapter V: Co-ordination with WFD

• Chapter VI: Implementing measures

• Chapter VII: Transitional measures

• Chapter VIII: Reviews, reports and final provisons

Chapter one is an introduction, in chapter two the rules for preliminary flood risk assessment are laid down and chapter 3 - most relevant for the flood mapping theme - is about flood hazard maps and flood risk maps. In the last draft the headline of this chapter was just flood risk maps. However scientifically it is important to separate in the directive that hazard maps and risk maps have to be differentiated.

Chapter four is about flood risk management plans. Here the coordination within cross-border river basins is crucial also for flood mapping strategies and for the adjustment with the water framework directive.

Regarding the theme of the FLAPP workshop on flood mapping chapter three is most relevant. There is described which hazard maps and risk maps are in the sense of this directive. This is supposed to be an important step forward to harmonization at least of the terminology in Europe. Many running projects should adopt to joint terminologies and methods as much as possible.

The directive regulates that both map types have to be completed for the European Rivers before Christmas 2013. So it’s still some years to go, but on the other hand experiences from large river systems have shown that such processes take some time. There is still a lot of work to be done. However the directive says that all maps which fulfill this directive already can be used to fulfill the recommendations. One condition is that they have to be in an appropriate scale.


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The scenarios for which these maps shall be produced are

• the low probability or the extreme event,

• the medium probability which means more or less the return period more than 100 years

• the high probabilities where appropriate.

Before, in the last draft, the high probability was defined with 10 to 30 years. This is skipped now and high probabilities have to be shown only “where appropriate”.

Hazard maps shall show the flood extent, the area where the water goes to in case of the scenarios. They shall show the water depth or the water level. If the water level is appropriate it can be used instead of the water depth. Where appropriate the flow velocity shall be shown.

Flood risk maps shall show the consequences of flooding. For the three scenarios or at least the two the consequences are indicated in terms of

• the number of inhabitants which are potentially affected,

• the type of economic activities in the area which is potentially effected,

• installations which might cause existential pollution and

• other information which can be useful as indication of risk – like sediment transport and debris).

3.1.3 Transnational projects that aim flood mapping (overview)

In Europe many projects and EU activities are ongoing to organize the flood mapping processes. In most of the European river basins flood mapping activities are running. A lot of projects are running on regional, national and international scale. Additionally a number of activities aim at the coordination of the approaches: projects of the Joint Research Center of the European Union (JRC in Ispra). In the EXIMAP project is an international initiative which is explained on the workshop separately (the report). There are more initiatives aiming at exchange and coordination of which one other is the FLAPP project. We see that we need frequent exchange to a step forward to harmonization.

Some examples for transnational flood mapping projects are:

• OderRegio

• ELLA

• SAFER

• TIMIS

• NOAH

Some of them are presented in this report. More information can the projects can be found in annex … (list of relevant information).


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In any case flood mapping will stay in the full responsibility of the single member states, so these initiatives can only assist the member state. It has to be done in the future in the framework of the flood directive and it will be supported by the European research and funding. The running funding period for regional development funds will end in 2008 and the preparation for the period 2007 to 2013 has started. This schedule meets that one of the flood directive. Issues of flood management will also be one important funding issue for the next funding period. So it would be wise to develop projects which are linked closely to bring together the initiatives and to combine the methods.

In Germany we have an additional problem: national border are one kind of borders, but at the borders between the “Bundesländer” – that have almost full responsibility for water management – also different approaches meet.

3.2 User groups and different demands of the user groups

The questions that should be asked at the begin of every flood mapping process are: 1. Why do which users need flood maps (user groups and purposes)? 2. Which are the demands of the different users?

From a number of projects different lists were created, partly laid down in guide-lines. That these lists differ is subject o the nature of hazard mapping, since users and demands relate to the specific regional conditions. The following explanations can just be an example. For practical mapping purposes the process of user group involvement to work out joint conceptions is important for acceptance and practicability of the mapping results.

Generally said the following purposes should be taken into consideration:

Information of the public / public awareness

Preventive land-use management (e.g. the definition of hazard zones),


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Precautionary measures of construction

Improvement of public awareness

Prediction and warning of floods

Disaster prevention/control

Flood insurance.

These purposes are subject of the duties of following user groups:

Private public / private bodies

General public / house owners

Insurances

Industry etc.

Authorities / public bodies

Spatial planning (regional planning, municipalities)

Flood protection agencies, water management

Flood management, emergency management, fire brigades etc.

Which user has which concrete demand to fulfill the purposes varies from case to case and from river basin to river basin.

However, exemplarily some user group demands are specified in the following.

3.2.1 Regional spatial planning The tasks of regional spatial planning in regard to flood mapping are:

Zoning of spatial uses

Zoning of hazards / risk

Balance between different demands

Therefore following hazard information is necessary:

Zones for urban use

Zones forbidden for urban use

Regional spatial planning aims at zoning the spatial uses to balance and to organize the zones and to integrate flood prevention. It’ s necessary to integrate hazard zones and risk zones into this zoning concept and to balance then what can be done and what not to define zones for urban use and zones where urban uses are not sensible in the case of flood. This leads to the first set of special demands and scenarios, content of maps and dissemination aspects.

3.2.2 Local land use planning The tasks of local land use planning in regard to flood mapping are:

Concrete decisions about land use

„allow“ or „forbid“ detailed uses

Precautionary measures (to „allow“)

No new urban use in flood plains

adapted buildings in risk areas

precautions for building in risk areas


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Local land use planning makes the concrete decisions where to build, where not to allow, where to forbid and where to take precautionary measures. This means at first to inform house-builders and architects about risks and what can be done to prevent damage in case of floods. So local land use planning needs the detailed information about flood plains, risk areas and of course the depth and more information.

3.2.3 Civil defence / emergency management The tasks are:

Prepare warn and alarm plans

Organise rescue service in flood cases (incl. co-ordination of civil defence organisations)

Training of rescue manoeuvres

Develop emergency management systems.

Civil defence is – especially in the international comparison - a inhomogeneous user group. The duties and the structures are very different in the countries and regions. Thus the demands are quite different. Civil defence departments of cities, fire brigades, rescue services – everyone has different demands. Here especially the formulating process of demands is crucial for the success of the mapping project.

3.2.4 Water management / flood protection agencies The tasks are:

Implementation of flood protection action plans

Plan / realise protection works

In flood events: protection of protection works.

To determine flood protection works and to set up flood protection plans the organizations in charge demand maps for flood events with different scenarios: with measures, without measures, combination of different (mobile) protection works etc.

3.2.5 Storage of potential pollutants The tasks are:

Permissions for storage of dangerous materials

Precautions for pollutions in case of floods

Communication in flood cases, protection.

The field “storage of potential pollutants” has been less discussed in mapping processes than other purposes of flood maps. But after flood events we always see how much damage is caused by pollutants. We have at least in Germany a very clear regulation about how to handle pollutants or dangerous substances, but these regulations basically aim at ground water protection and direct impact of dangerous liquids on the environment. But they do not relate directly with flooding. So here link is urgently required. To give permissions, to order precautions and to communicate risks are the least requests. From this different additional demands on flood maps result.


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3.2.6 Insurances The tasks are:

Insure single households and businesses / industry

Risk assessment on a details level (for single sites and buildings)

Detailed hazard / risk information.

Insurances and reinsurances are a very special field because the communication between insurances and other producers of flood hazard and risk maps is not very transparent. Because here are companies who needs to know very much about different risks. On the other hand is the public that should not exactly know what the insurances know. So this field is not very transparent. They have different demands. Insurances need to have information about single house-holds and very specific sights. They need very detailed information and have specific demands. Insurances have own methods and mapping projects which not generally is shared with other producers and users of maps.

3.2.7 Conclusions for the definition of demands It is impossible to define the demands of so many different user groups just theoretically and in general. In opposite, regional conditions, physical, political and spatial conditions are the framework for the definition of the concrete demands and contents for the flood maps. Even the users have to be defined individually for special cases.

However, the process to reach this list of users and demands is crucial. Thus the process of the “user demand evaluation” should always be in the focus of the first phase mapping activities.

The following table or a similar system should be filled in during the user participation process. General lists of potential users and relevant criteria can be used.

Map … / User … Map … / User … Map … / User …

Scale

Aim

Contents

Accuracy

Covered areas

Target groups

[…]

3.3 The framework of the planning systems

One of the important users is spatial planning on different planning levels. The comparison of the planning systems throughout the countries all over Europe shows very different systems, causing very different demands on flood mapping by spatial planning.

In a study we have finished in 2001 (Böhm, Heiland, Dapp, Haupter 2001) we compared the planning systems of different countries. One important result is that the legal function of flood maps in the planning systems varies much (see the figure below). Important are the broken lines and arrows which tell about the binding consequences of flood map information on spatial planning decisions.


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Fig: Flood maps in spatial planning systems in Germany, France, Switzerland and The Netherlands (from: Böhm, Heiland, Dapp, Haupter 2001)

France

Switzerland The Netherlands

Germany


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In Germany for example flood plains in the sense of the water law cause far reaching impacts on the possibilities of land in these areas. But flood hazard areas shown in flood maps (beside the flood plains) have consequences only if they are integrated into the spatial development plans. That is different in France, where there is a binding component of flood prevention plans. In Switzerland hazard maps have legal consequences for local development planning and in the Netherlands there’s also no directly binding consequence of risk maps so far.

To deepen this evaluations please see Böhm, Heiland, Dapp, Haupter 2001 and other international comparison studies about spatial planning and risk management (see literature list in the annex).

An additional example from the user-demand studies is the determination of risk areas for spatial planning. The following figure shows flood areas in a river valley. It shows the different areas that ar e subject of flood hazard maps and the transfer to regional spatial planning zones (example in the German legal framework).

Figure: Flood hazard information and transformation to spatial planning zones (example from Germany, acc. to Heiland 2002)

The information where the one hundred year flood occurs is the basic one. This is more or less similar in other countries and subject of the flood directive (draft) now. Additionally spatial planning needs risk information from extreme flood events. Spatial converts these areas to “priority areas for flood risk reduction” which should be kept free of housing or which could be used as extension for retention areas. Secondly reserve areas are designated risk areas which can be used for housing if precautionary measures are taken. In Germany priority zones are areas of the hundred year event. These are also subject of the water law. The other zones which are beyond the one hundred year event are the issues which should be shown in hazard maps.


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4 Presentations of the Workshop

4.1 Process of Flood mapping – examples from the „Oder Flood hazard maps“ (OderRegio project) JÜRGEN NEUMÜLLER INFRASTRUKTUR & UMWELT, PROF. BÖHM UND PARTNER, POTSDAM

Introduction

The basin of the Odra River covers a transnational catchment of 118.861 km². 89,9 % of this area are Polish, 5,4 % Czech and 4,7 % German. Due to the fact that Germany is placed downstream it has very much interest in flood protection and in collaboration with Polish colleagues. The Czech part of the catchment is characterised by mountains and high rainfalls compared to the rest of the catchment.

During the extreme summer flooding in 1997 the damages concentrated in Czech Republic and in Poland, estimated about several billion EUR. To face the flood danger in future midterm to long term transnational activities are needed. Therefore the International Commission for Protection of Oder (ICPO) set up Flood action plan in 2003 presenting general goals, measures and costs.

Flood danger or flood risk maps are not available for the catchment. Only one comprehensive flood map exists which shows the flood situation (1997 flood extent) along the Oder river: WWF Flood plain atlas which focuses on nature (scale 1:50.000). Other flood mapping activities so far were only of local/regional relevance. Therefore in the OderRegio Interreg IIIB project flood mapping had to be started rather from beginning.

Goals of Flood Danger & Damage Potential Mapping

The mapping process in OderRegio is basing on a top-down approach focusing on different target groups. These target groups are:

- People in risk areas - Regional Planning - Local Authorities - Water Management Authorities

The target groups as well as the purposes of use of the different maps are presented in Fig. 1 and Fig. 2.


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Starting point and principle stages of the mapping process

Before starting the mapping process the following questions had to be answered:

Which scale is fitting with regard to the fact that more than 500 km of the Odra river shall covered by maps?

- A scale of 1:50.000 was chosen as basic scale. But where needed and wished and justified with respect to quality of data 1:10.000 rsp. 1:5000 should be possible

What content should be on the map? - Flood area and flood depth (no velocity) - further additional information (e.g. gauges with water levels for considered events, river

kilometrage, administration boundaries, …)

Should damage potentials be estimated on basis of flood danger maps? - Yes!

Which events should be shown on the map? How will the extreme event be defined? - Different definitions are possible for the extreme event. In the project the design water

level of the dikes was chosen for the border part of the Odra. For the Polish and Czech part the 1997 flood event was defined as an extreme one.

- As additional information 100 year flood and 10 year flood lines will be shown.

For the mapping process the following principle stages could be identified:

1. Generating a Digital Elevation Model

2. Modelling first stage: Calculation of water levels along the river (in different scenarios)

Fig. 2: Damage Potential Maps - Target Groups and purpose of use

Fig. 1: Flood Danger Maps - Target Groups and purpose of use


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3. Modelling second stage: Calculation of flooded area (including information about water depth

4. Implementation in flood danger maps

How to choose a model?

Different types of models are necessary during the mapping process. To minimise problems different conditions should be fulfilled for the chosen models:

The elevation model should be - sufficient in accuracy in height - available - digital - transformed into one coordinate system and meridian - prepared for modelling (proof of flow directions, line information)

The hydraulic model should be - accepted by responsible authorities (preferable when it is in daily use already) - calibrated and validated - used only when it derives right results

(ice and wind influences !)

The next step ‚Calculation of flooded area’ should be done - not by simple intersection of 1D-water level with terrain - in combination of 1D- and 2D-approach in order to consider retention effects in

floodplains - without main dikes (which represents a combination of all potential dike breaches

along the river) - with special methods for large flood plains (simulation in time)

How to get and how to prepare data?

For the process of data gathering and preparation the following problems could be sorted to data groups

- the DEM was not available in right accuracy - cross sections are not sufficient - river network and kilometrage do not harmonise - topographical background information is different - mMissing international rules for exchange data!

To overcome those problems the following activities were realised: - regulations and costs/fees depend very much on how results will be published (first

produce product then talk about publishing) - use data which is confirmed officially - use coordinate system where most of data is available - improve existing data (e.g. Interpolation of cross sections) and not wait for better data

Content of the maps

The study area for which maps will be produced covers more than 500 km of the Oder. The content of the 52 map sheets in the scale of 1:50.000 is summarized in the following table.


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Flood Danger maps Damage Potential maps

Flood boundaries for HQ10, HQ100, HQextrem Areas of damage categories of land use classes

Flood depths for HQextrem Damage [€; PLN] Gauges with Water levels for HQ10, HQ100, HQextrem Concerned people (water level < 2m) Stream network + kilometrage Endangered people (water level ≥ 2m) Administration boundaries Concerned objects, e.g.: Industry, roads, railway, water

supply, hospitals, fire brigade and police, cultural heritage

Background: Topographical map 1:50.000 Background: topographical map 1:50.00

How to produce accepted maps?

To produce maps which are accepted officially it is an important step to involve responsible water management authorities directly. This can be realised by integrating them into e.g. modelling tasks and/or plausibility check of results. This could be organised in working groups, experts workshops or individually.

Involvement of end users

The target groups of the maps are the end users. They are represented by people in risk areas, Regional Planning authorities and Local authorities. Those groups can be reached by different activities, like:

- brochures, - conferences/meetings, - direct involvement within the process, - dissemination, - printed atlas, - single maps - interactive maps

Conclusions for flood mapping processes

1. Active involvement of responsible authorities is essential for success of flood mapping process in many ways

2. Data quality defines very much scale and quality of results

3. Decision about used model is not of highest importance

4. Without rules for international exchange of data flood mapping process is a hard business

5. Other experiences and philosophy in different states require a lot of definition work

6. Transnational co-operation needs extra time (and money) but it is worthwhile !

Conclusions towards cross border flood mapping

Obstacles - insufficient data quality - access to relevant data is difficult (needs extra-time!) - process of finding accepted definitions (needs extra time!)

Solutions - involvement of responsible authorities - rules for international exchange of data are necessary - extra time must be considered in transnational collaboration

Dissemination - first produce maps, than decide about dissemination


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4.2 Practice examples from different rivers

4.2.1 Cross border flood hazard maps - Experiences from the TIMIS flood project I. E. LEISS ET AL. ERNST BASLER + PARTNER AG, ZOLLIKON, SWITZERLAND.

Towards a uniform EU policy for flood protection

In the last years, several European countries were struck by serious flooding (e.g. Mosel, Saar, Sauer in 1993 and 1995; Oder in 1997; Austria, the Czech Republic, Germany and France in 2002; South Germany, Austria and Switzerland in 2005. These events cannot be prevented. However, the damages can be reduced by means of suitable planning bases, reliable forecasts, and warnings. In the border area of Luxembourg, Germany and France, seven authorities are developing a transnational information system for flood.

The project TIMIS flood

The project «Transnational Internet Map Information System on Flooding» (TIMIS flood, see http://www.timisflood.net) is funded by the European Community Initiative INTERREG IIIB for North West Europe. It is a contribution to a uniform EU policy for flood protection and shall become a model for other regions affected by transnational flood issues. In the framework of TIMIS flood a huge amount of data is collected and analysed for an area of 55'000 km2. TIMIS flood aims to harmonise the data and provide customised informa-tion. The following products will be available in 2008:

- transnational hazard maps (cross-bordering, homoge-neous, four hazard stages)

- transnational forecast and warning system (improve-ment of the existing forecasting system, flood warnings for small catchments)

- transnational GIS on flood (hazard, forecast and warn-ing)

- transnational Internet service (easy access for the citizens, web services: data, maps, reports)

Approach for the hazard map generation

The generation of hazard maps can be divided into four main steps: 1. High-precision digital terrain model (DTM)

Elevation points were derived by the means of airborne laser scanning during the winter months. The point density varies between one to four points per m2, depending on the sensor used. The points have an elevation accuracy of ±0.17 m (must be true for 95% of the points on homogeneous areas, e.g. football fields). For better terrain representation, breaklines from photogrammetry and field survey were additionally integrated into the DTM.

2. River cross-sections The river cross-sections were acquired in the field using tachymetry. Apart from the elevation of the river bed, also hydraulical parameters like roughness and vegetation were acquired. The distance between the cross-sections is 100 to 200 meters


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depending on the river morphology and the surrounding land use. Obstacles, e.g. bridges and weirs, are photographed.

3. Hydraulic modelling For 95% of the rivers, a 1-dimensional modelling (steady and non-uniform) are applied. The remaining 5% of rivers, situated in the Rhine plains in the SE of Rhineland-Palatinate, are modelled by the means of a 2-dimensional approach. Ten different probabilities of occurrence (from MHQ*0.1 to HQextreme) are calculated leading to water levels and flow velocities. The representative run-offs were determined using a statistical analysis of gauge levels and a regionalisation approach.

4. Hazard classification Four hazard stages are generated by the means of intensity (water depth * flow-velocity) and probability (hazard matrix). The hazard maps are available as printed copy (scale 1:25’000) and as GIS dataset (scale 1:5’000). Existing hazards maps (France, Interreg IIC projects) are integrated to achieve an area-wide coverage.

Challenges and Strategies

The heterogeneity of data is a special challenge for the project team: Different acquisition times, scales, accuracies, cartographic projections, data formats and models hamper the interpretation. In TIMIS flood these problems are encountered by three measures:

- managing all the data in geodatabases and in their original map projection - collecting meta data for all datasets - using methods which can manage data inhomogeneities

In the project area, i.e. Germany, Luxembourg and France, there are already existing hazard maps. They shall be integrated into TIMIS flood. However, they all use different hazard categories and representations. In TIMIS flood, we try to combine the different approaches and show them as «common denominator».

Today, flood information is mainly distributed by videotext, radio broadcast, SMS, and Internet. In the future, the Internet is expected to play the major role. Web services will distribute the information to different stakeholders. However, there are considerable differences between the stakeholders with regard to requirements and interests, knowledge and possibilities, as well as to their culture and regional mentalities. For this reason, TIMIS flood organises workshops for different stakeholders to clarify their needs. Based on the results, prototypes are developed and again discussed and clarified with the users.

Recommendations and Conclusions

After 50% of the project time, the project team can provide the following recommendations: - involve responsible authorities also if they are not in your project team - consider comparable accuracy for all steps during the hazard map generation - define minimal data models which can be extended by the national needs - integrate the hazard maps into existing frameworks (e.g. use existing map sheet

divisions) - promote the hazard maps actively and down to the citizens (the «last mile») - exchange knowledge with other transnational projects dealing with flood protection

Regulations are welcome in order to harmonise the transnational hazard map generation. However, the following guiding ideas should be considered:

1. as little harmonisation as possible - else you kill cooperation, and 2. as much harmonisation as needed - else you kill efficiency.

Conclusions towards cross border flood mapping Obstacles - Data heterogeneity (scales, accuracies, projections, formats, models)


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- To present already existing hazard maps in border regions with different hazard categories and illustration

- To satisfy all user demands towards flood information

Solutions

- Managing all the data in geodatabases in their original map projection - Collecting meta data for all datasets - Using methods which can manage data in-homogeneities - Combination of different map approaches by showing the “common

denominator” - Involve responsible authorities also if they are not in the project team

Dissemination - Development of user specific web services - Promote hazard maps to citizens

4.2.2 Flood maps for the cross border cities of Görlitz (D) and Zgorzelec (PL) ANDRÉ FREIWALD SAXON STATE AGENCY FOR ENVIRONMENT AND GEOLOGY, DRESDEN, GERMANY

Introduction

The project area is placed at the German-Polish border on the territory of the cities Görlitz and Zgorzelec. The Nyssa River forms the border between Germany and Poland. Both towns were separated in 1945 after the World War II. An intensive cooperation started since the 1990ies. Both cities suffered from flood events in 1981 and 2002.

In the project the following departments of the city administration are involved: Crises management, spatial planning and regional water authorities (only from Ger-man side).

Two types of maps were developed in the project frame-work. These are Flood Information Maps and Flood Hazard Zone Maps.

Flood Information Maps

The relevant input data for the flood information maps consists of: - Topographic base maps (scale 1:10.000) - Geographic information system (GIS) flood data for different scenarios - Information about endangered objects, infrastructure and crisis management

Additional flood scenario data were necessary. Those data based on Saxon flood control plan for the Nyssa River in 2004:

- 1-dimensional model (WSPWIN) - Bilateral agreed discharges/flows - Digital elevation model 5mx 5 m (Aero triangulation)

The outputs are GIS-shapes-files for different flood scenarios (20-, 50-, 100-, 200-, 500-years event). They are part of the map content which includes:

- Information for the crisis management - Information about endangered infrastructure


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- Flood information (flooded areas for 5 flood events)

Flood Hazard Zone Map

The main input data for this map type are topographic base maps in the scale of 1:10.000 as well as GIS flood data for different scenarios. The main intention of this map type is the presentation of hazard zones. Therefore the intersection of intensity and probability of a flood event is realised.

The final content of the maps are four different risk areas (high risk, medium risk, low risk, residual risk), representing recommendations in relations to land use limitations/restriction.

Conclusions - First step in cross border cooperation: Create a joint “product” on the basis of existing

data - Improve cross border cooperation via “informal networking” - Incorporate end users in the flood map generation process


Obstacles

Creation of mutual topographic base map is necessary; such a product is normally not available. It was not possible to integrate responsible Polish water management authorities into the project. Lack of a digital terrain model for the Polish side.

Solutions

First step in cross border cooperation: Create a joint “product” on the basis of existing data Improve cross border cooperation via “informal networking”. Incorporate end users in the flood map generation process. Cooperation with transnational river commissions from the beginning of the project could be helpful and is evaluated as more efficient than integration of authorities.

Dissemination Dissemination depending on authorities, no incorporation of citizens in the project framework. Top-Down-process, only involvement of authorities.

4.2.3 Experiences from the Rhine-/Elbe-Atlas PETER ZEISLER & ANDRÉ ASSMANN RUIZ RODRIGUEZ+ZEISLER+BLANK, WIESBADEN-BIERSTADT, GERMANY GEOMER GMBH, HEIDELBERG, GERMANY

Introduction

Flood risk mapping follows different objects. Those can be:

- Keep risk in mind - Demonstrate effects of protection measures - Cost/benefit analysis - Risk zoning - Basis for rescue services - Fast damage estimation on real events - Basis for sustainable spatial planning


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Available maps

After the presentation of these main objects, an overview about available risk maps and maps that are already in processing is presented. ‘Rheinatlas’, ‘Gefahrenhinweiskarte Sachsen’, maps in the project ELLA – Saxonia-Anhalt and for the River Mulde are already available. Further maps are actually in preparation. Among those are risk maps for the River Elbe (ELLA, Interreg III CADSES), the River Oder (ODERREGIO, Interreg III CADSES) and the Lower Weser (RISKEOS, ESA GMES) as well as test regions in Danube catchment (PREVIEW, FP6 GMES).

Work process

For the work process, working steps as well on administrative as on technical level have to be considered. Administrative working steps include:

- Listing of concerned institutions - Definition of Aims - Definition of target group - Definition of Scale and Resolution - Kind of Presentation

Problems which can occur during this process can be e. g. different administrative structures or different legislations. But also different languages and a possibly missing confidence can cause problems in the working process and lead to delay.

On the technical level, the following working steps are named: - Scenario definition - Data gathering - Data preparation - Quality control - Simulation / Calculation - Cartography

In this framework also different and numerous problems are presented based on the experience of different transnational projects. Problems can occur in relation to projection/transformation of data, like missing projection/transformation information or projection/transformation errors. Another field of obstacles concerns data formats. Often the documentation of data (-format) is insufficient or not available. But also large data sets (laser scan data, CAD-format) can cause data handling problems. A further problem-field are DTM-linked obstacles presented by tiles-effects, steps at administrative borders, different DTM quality even within one data set or stairs-like-DTMs (integer data). Missing data for neighbouring regions is a further problem that can be faced.

The clear definition of scenarios depends on different aspects. These are: the aim of study (sensitisation, re-gional planning, preparation of rescue service, cost-benefit-analysis, building activities), the availability of data (model results, input data) as well as the available budget.

Based on this framework conditions the simulation methods have to be chosen. It must be distinguished between ‘1D-calculation and GIS-intersection with DTM’, ‘1D/2D-coupling (e.g. FloodArea)’ and ‘2D-simulation’. Before the simulation process starts the handling of protection measures has to be clarified as well as the impact time of the chosen event: Calculation without protection measures or calculation of different failure scenarios (e.g. break or overflow).


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Before the final creation of the maps a discussion about the final map content is necessary. This includes: Inundation depth, flood extent, flowing velocity, flowing direction, map background.

Conclusions - Data sets are still very heterogeneous, more standardisation would improve the quality

and reduce the costs - Data documentation is very poor - Availability of data from adjected regions is very limited


Obstacles

Administrative: different administrative structures, different legislations, different languages, possibly missing confidence Technical: DTM (tiles, steps, different quality), projection (not available, transformation errors), large data sets, missing data for neighbouring regions

Solutions

Standardisation would improve the quality and reduce the costs Improving metadata information High-level talks (with directors) are necessary in Poland for the integration of relevant authorities

Dissemination -

4.3 Use of flood maps for flood management

4.3.1 Hazard Maps for Stendal County in Saxony-Anhalt MANUELA GRETZSCHEL INSTITUTE FOR WATER MANAGEMENT - UNIVERSITY OF APPLIED SCIENCES, MAGDEBURG, GERMANY

Introduction

Stendal County is placed in Saxony-Anhalt and was strongly affected by the River Elbe Flood in summer 2002. During this event nearly 30,000 people were evacuated and thousands of emergency management forces were in use. Due to dike breaches in the upper parts of the Elbe basin no dike breaches or victims occurred in this area.

Flood Management System (FloMS)

Due to this event and the coordination problems which occurred in-between the administration and the emergency helpers it was decided to establish a Flood Management System (FloMS) for Stendal County to be more efficient and better prepared in case of future severe flood events. Such a system should integrate a structure for flood prevention and emergency management and provide all necessary information and datasets. A further relevant aspect was the supply of a working platform to support the decision makers (Decision Support System - DSS). These tools should be used to improve data basis and to model simulate potential flood scenarios. Further requirements


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Localisation and predefinition of measures InformationAim

Flood Management System

Non geographical information Geographical information

Internet capable Information- and work platform

Content Management System (CMS)

Web GIS

LegislationRecommendation . . . Technical dataGeobasis data Scenarios

PC 1 PC 2 PC 3 . . . . . . PC n

Internet presence

Geographical information

Non geographical information

Project information

Responsible persons in Stendal county Population

Rea

lisat

ion

Con

tent

sTy

peU

ser

Web-Server

- CMS-Station- CMS-Server

- GIS-Station- WebGIS-Server

- HTML, JAVA

Internet browser Internet browser

PC 1 PC n

Fig. 3: structure of the flood management system.

towards such a system are an open structure allowing to extend and to transfer relevant information.

The system consists of two main columns. These are first a content management system (CMS) serving as Information platform, steering of FloMS and being interactive and available as open source software. The second column is a Web-GIS allowing Web-Publishing, providing necessary GIS-functionalities, integration of own geodata and the decision support for measures.

The spring flood of 2006 was a first test for the developed FloMS. A first practical application took place during emergency management in Stendal County in April 2006. Major hazards during this event were the flooding of villages because auf rising water levels, instable dikes, dike-cracks and the overflowing of an important bridge. The WebGIS application of FloMS was used to obtain an overview about situation and to gather information about dikes, defence of dike ways or hot spots. The CMS was mainly in use for registration and overview of action forces.

Hazard maps for Stendal County

Establishing Hazard maps for Stendal County was one of the main goals of the pilot project and within the European project ELLA. In the process of the map development the following stakeholders were involved:

- Responsible people of Stendal County

- Stuff of LHW, responsible for flood pro-tection structures

- ELLA, working group 3

As results of a discussion proc-ess and several work meetings the regional scale 1:50,000 was defined as sufficient and two kinds of maps: One printed version (format DIN-A3, landscape) and one digital version which is provided by the Web-GIS. The printed version is necessary to have all information on site in case of emergency. The content of those maps can be taken from Table 1.


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Table 1: Comparison of the content of printed and digital map versions

Content Description Print version Digital version

Flooded area and water depth

HQ100 with/without dykes, EHQ without dykes from ELLA-hazard indication maps X X

Flood protection structures

Dikes, Dike sluices (Siele), pumping stations (Schöpfwerke), Dike openings (Deichscharten), Polder, Gauging stations (Pegel)

X X

Structures important for discharge

Bridges, culverts (Durchlässe), Weirs X X

Hot spots, special risks Gas stations (Tankstellen), Factories (Industriebetriebe) X X

Endangered public institutions

Day care centres, Schools, Gyms, Hospitals, Senior residents X X

Public Supply Water works (Wasserwerke), Sewage Treatment Plants (Kläranlagen) X X

Infrastructure Railways, Major roads X X Memorials (e.g. churches) n.n. - X

Contaminated sites n.n. - X

The use of FloMS focuses on administrative level. To integrate also citizens and to provide relevant information to a wider range of interested persons it is foreseen to provide an extra platform for public use presenting non-geographical as well as geographical information. This component will have limited degree of information and functions compared to the main components (CMS and Web-GIS).

Conclusions - The developed FloMS of pilot project Stendal is one output on regional scale - The implementation of FloMS in emergency management was successful applied

during flood 2006 - The product is a helpful decision support system for action forces

Conclusions towards cross border flood mapping, including discussion

Obstacles

Publication and distribution of maps has to be paid for in Saxonia-Anhalt. Due to this it is not clear which maps can be shown. Data purchase took very much time (3 years) Accuracy of available geobasis data is not good enough for flood protection purposes, data has to be improved

Solutions Most important maps will be shown still

Dissemination

Separated into dissemination for experts and dissemination for citizens via internet Two ways of map dissemination are used: Digital datasets and printed copy (scale 1:50.000) for on-site-availability in case of emergency alert.


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4.3.2 FLIWAS and flood maps KEES DE GOOIJER HKV CONSULTANTS, LELYSTAD, THE NETHERLANDS

Introduction

The target of NOAH-project is the optimization of the exchange of information during (threatening) high water situations within and between water management and emergency management organizations. Further more the project intends to minimize the uncertainty gap between critical and calamity water level. The motto of the project is “The right information at

the right time at the right place, to take the right decision”. Target users are Professionals (managers and decision makers, operational employees and coordination centres) as well as the public and private companies and the media.

The communication with the public is realized by a public interface. Further more information for other websites is provided. “Hochwasserpartnerschaften” are initiated to increase public awareness.

FLIWAS

One important part of the NOAH-project is the development of FLIWAS (FLood Information- and WArning System). The following aspects are considered within FLIWAS: Measurement and monitoring (water discharge and weather), emergency plans, flood maps and scenarios, evacuation and evaluation.

For the creation of flood maps different scenarios have to be defined. The scenarios consider high water wave, breach location as well as time related flooding pattern with water height. Depending on the scenario FLIWAS allows to develop an evacuation strategy as well as to locate the number of people, animals, industry and special objects as national heritage, hospitals and senior citizens homes. Therefore infrastructure and traffic models are considered and the evacuation time or number of people that can be evacuated can be optimised.

Advantages of FLIWAS: - User only sees the information that he/she needs - The system warns users, involved persons or other organisations if actions are not

executed - Direct link with external data such as measurement systems - Standardized situation reports with on-line information - All actions of both user and system are stored and can be used for evaluation - The system can be used for communication on-site - The system can be provided at other locations (regional or national level) by

professionals and public

Further characteristic: - Multi language application - Web based (server-client-system) - Web mapping component - Multi platform application (Windows, Linux, MacOS) - Access with common web browsers (PCs and Handheld)


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- Modular System with generic components - Information and communication system - Open source for public authorities - Including use of standard software, if necessary

Flood Maps

Within the presented project different types of flood maps are produced. This are: - maps presenting flooded area incl. maximum water level - maps presenting flooded area incl. moment of inundation - Flooding movie incl. maximum water level and moment of inundation

Those maps can be used to set up evacuation plans, to calculate damage and victims or to analyse costs and avail for measures to increase the level of protection.

Conclusions (towards cross border flood mapping), including discussion Obstacles Solutions Dissemination Public interface

4.3.3 European exchange circle on flood mapping - EXCIMAP FREDERIQUE MARTINI MINISTERE DE L’ECOLOGIE ET DU DEVELOPPEMENT DURABLE, FRANCE

Introduction

The Water Directors of the European Union have acknowledged that a common need in Europe to carry out flood mapping exists. Furthermore many experiences and know-how about flood mapping is already available in Europe. This experience should be gathered in a European exchange circle on flood mapping called EXCIMAP. The objectives of EXCIMAP are:

- making an overview of current practices in flood mapping in Europe. - identifying knowledge and good practices to share - writing a guide of good practices on flood mapping

The framework of the project follows acknowledged definitions, existing types of flood maps and the proposal for a European flood directive. Furthermore the work builds on reviews and works done on the subject as well as operational and current practices.

The project team consists of 33 participants from 15 European countries, international hydrological commissions, EU projects, European organisations and other interested stakeholders. The co-pilot are the Federal office for the Environment (Swiss confederation) and the Ministère de l’écologie et du développement durable (France). Also an exchange with existing projects working on the subject (e.g. FLAPP) is realised.


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Actual Activities

The review of current practice is one important issue. Therefore a questionnaire was developed, addressing:

- Types of flood maps, types of flood addressed - Legal value, accessibility, format of the maps - Methodology, data sources, models - Vulnerability assessment - Other reviews, specific needs, precise knowledge

One central outcome of the project will be a Guide of good practices. The objectives of this guide are to give an overview of the existing good practices in flood mapping in Europe and to serve as a reference’s document for flood mapping implementation or updating. The content of this guide will focus on:

- What is flood mapping and why do we map floods: definition, purposes - The flood mapping process: good existing practices - Dissemination of flood maps: formats and broadcast technologies - Examples/illustrations from national practices in Annex

Two writing sessions took place up to now, working out first drafts of the planned guide. During those writing session common points could be worked out as well as different views. The common points are e.g. for Flood plain maps: Delineation of flood prone areas for events of one/several return periods; theorical flood extents, covering all the territory (few exceptions), associated to a legal process; used in support of land-use planning, from hydrological analysis and modelling (1D-2D)+high-precision DEM, based on historical observations.

Different views exist concerning e.g. the following item of Flood plain maps could be identified: Scale, indication of flood defences locations; defences failure possibilities, floods frequency references, input of land use development and climate change effects.

A third writing session will take place in 2006, the final version and publication of the Guide of good practices is planned for 2007. The writing sessions are open for interested stakeholders.

5 Discussion and Results

5.1 Definition of maps: users; science, demands The writing session was chaired by Peter Heiland (INFRASTRUKTUR & UMWELT, Darmstadt)

The questions for this session were:

Users and demands • Are user groups generally defined or very specific? • Which are most relevant user groups in the examples? • How were the users integrated into the process? • Which were the specific demands of the user groups? • Which demands were especially subject of discussion in the examples? • Which demands should apply

- generally - for special situations / users

Policies • Which of the demands of the EU directive (draft) are fulfilled (not fulfilled) in the

exemplary approaches? • Which specific national policies are significant for the examples?


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Users and demands

The discussion focussed on the question whether general guidance is possible regarding the determination of users and demands. One key issue of the discussion was the conclusion that it is not possible to name users in general. Lists that have been produced could be used as checklists to start the process but in each project a specific participation process is necessary.

The result of this first phase of each mapping process must be an individual and regionally specific user evaluation and determination. The user groups have to be identified and should participate in the processes as soon as possible.

In the second phase a participative process with all (potential) users should be started to develop a joint catalogue of demands of all users. The demands will always be different for each user group but can be harmonised in the process.

This is also a central task for cross border mapping projects, since international differences in legal framework and planning systems as well as differences in mentality will cause different demands. Here time should be taken to discuss the demands jointly and to conclude with joint approaches for a whole river basin.

Examples were presented in the sessions of the workshop (see presentations).

Standard catalogues like presented in guidelines or in the EXIMAP approach can help to start the participation procedures. But the general list will not substitute an individual process. Beside the goal of working out joint demands for the maps one important aim of the user participation is the identification of users with the maps and by this the acceptance of the results. If the participation starts in an early stage of the project the chance can be raised that all user will accept the maps and will work with them.

Additionally the following summarising key words of the discussion in the workgroup have been noted:

1. User groups • Regarding the EXIMAP initiative: if users, demands and required

categories are listed, it must be an open list. It is most problematic to miss any regionally potentially important user group in the process (agriculture, forestry, insurances, companies etc.). On the other hand not all have to be involved in each project.

• For detailed maps: yes • For overview maps: no • Different processes for different user groups.

• The private public is the most difficult target group in the mapping process. This group has quite special and partly difficult roles in the flood management activities. Thus it should be decided in each case, whether the public should be involved in an own participation process.

• Similar problems appear when involving municipalities.

2. Demands • There are no standards for all river basins. The mapping projects have to start with

asking the users: the process of formulation the demands is important. • At first the definition of purpose is important (effects), then the user groups. • Invite all user groups to the definition process.


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• Do not produce maps first and then “sell” maps to the users.

• The goals of every participation process should be clear (also with politics): improvement of maps and raising the acceptance. If changes in the maps are not wanted as result of user group participation, then tell this to the participating groups; then it is an information process, not participation.

• Problems: • Bring all together, start the process, attract the

users • Inform users, do not make them afraid (leads

to opposition) • Interpretation of the maps is difficult: make it

easy • Public difficult, municipalities too

Policies

In the discussion the question is tackled whether the flood directive will bring major new demands for flood mapping projects. The overall conclusion is: no.

The mapping projects represented on the workshop already fulfil the demands of the directive.

3. Cross border specialities • …cross border rivers need river basin wide definition

of demands (content, scale …)

• … the process should be organised in a cross border approach.

5.2 Processing of maps This writing session was chaired by André Freiwald (LfUG Dresden).

The goal of this writing session was to find answers to the following questions in relation to processing of maps:

- What shall be the minimum standards? Which demands do not need or even should not be standardized?

- Is it good to harmonise a European data model? - Data availability, purchase in transnational basins? - What are the criteria to choose a model?

The working group decided to write down demands for the following three fields of map processing:

- Input Data - Methods - Products


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Each demand was afterwards categorised in one of the following categories: - “must” - demand has to be fulfilled (obligation) - “shall” - demand shall be fulfilled, no obligation, but would be helpful - “needn’t” - demand need not to be fulfilled, no need from the experts point of view for

such a demand

Input Data

Concerning input data the following demands were defined: Due to the fact that gathering of relevant input data is usually a very intensive and time consuming process regulations are needed that allow a free access to existing data from authorities. Such a free-data-access was categorised as „MUST“. Exemplary data handling was reported from U.S. where free-access to basic data is state of the art. Also from the Hungarian colleagues easy access to relevant data was accounted for their country. In the other countries, where experience was available (e. g. Netherlands, Germany, Poland), data access is difficult.

A further “MUST” was allocated to the need of metadata provision. The definition of metadata is an unavoidable need for the data user to be able to interpret data in the right way and to find answers to open questions occurring during the data use and the map processing.

Further more geo-information “MUST” be available in a digital form. This is sometimes still not the case.

Concerning the data format of the input data, they “NEEDN’T” to be available in the same format. This demand is not necessary because today software tools allow conversion from one format to another.

Methods

Different methods can be applied to determine run-off in the river bed. A very common approach is the use of statistics on the basis of time series. If these data are available they “SHALL” be used. But this can not be defined as obligatory because statistics are not always available area-wide and sometimes the estimation from an expert is also necessary and/or helpful.

Furthermore in border regions, where the river represents the border line between two countries or crosses the border between two countries the run-off “MUST” be harmonized to avoid different water level calculation. This aspect should be part of a joint agreement about the scenario definitions for the border river.

In this context a clear demand of precise scenario definitions in space and time was formulated. Such definitions “SHALL” become state of the art for all future mapping projects and shall include e.g. the duration of a high water level in a specific location.

For the calculation of water levels the same hydraulic approach / the same product “NEEDN’T” to be applied. The question to use 1D- or 2D models can not be answered in general. This depends on the river characteristics and the vulnerability of the study area.

Products

Five demands were formulated for the products of the mapping process. First of all, the production of maps in paper version as well as the supply of WebGIS/Web Services was discussed. Both types “SHALL” be produced. The specific need depends on the project framework conditions and the specific demands of the users. In general the current development is shifting from paper-maps-only towards digital results. This means that all gen-erated data like water levels, flooded area a. s. o will be available via web services while end users can generate their maps according to their needs on the basis of these data.

In addition it was underlined that the results “SHALL” be validated by the local authority to obtain a better degree of acceptance of the maps.


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Furthermore all results that were produced in the mapping process (cross border DTM, raster information of water depths and flow velocities …) shall be transferred to the responsible authorities for further future application. Thereby it is important to keep original data (e. g. raster) to maintain as much accurate information as possible. A complete backflow of digital products developed during the mapping process should become standard. Those data “SHALL” be delivered as GIS-data.

The definition of a standard map design (colours and scale) was stated as not necessary. The summary of the writing session can be taken from

Fig. 4.

Fig. 4: Summary of the writing session B. Demands on the processing of maps.

Open Questions

Not intensively discussed could be the question which common denominator should be used. But it was agreed that common denominators “MUST” be specified.

Also the question if unified data models are necessary for hazard information could not be discussed.


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5.3 Policy relevance This writing session was chaired by Annelieke Laninga-Busch and Bart Swanenvleugel.

The working group discusses the following issues concerning cross border flood mapping: - Why is cross-border flood mapping necessary? What are the benefits? - If cross border flood maps are necessary, why are they not generally applied? What

are obstacles and difficulties for making cross border flood maps? - Whose responsibility is it to generate cross border flood maps? - Looking at the benefits, the difficulties, the responsibilities, what is needed to get cross

border flood maps?

Why cross border maps?

1. In Europe the solidarity principle is broadly accepted. For water management this resulted for example in the river basin management approach (Framework Directive, draft Flood Directive). Taking this serious means that flood maps of joint river sections across borders should at least fit together (same starting points, same data etc.). So it is not necessary that there is one map (type) available for a whole river basin, but border sections should match.

2. Cross border cooperation in making flood maps of border areas is more cost effective. For examples expensive techniques like laser scanning are relatively cheaper if the border area is scanned at once instead of separately by two countries.

3. In the case that on either side of the border domestic areas are situated (like the example Görlitz/Zgorzelec) common flood maps will be a starting point for efficient emergency and calamity management (plans) across borders.

4. Cross border flood maps can be trigger for common measures in the border region. They provide a common basis for an integrated cross border approach of flood risk management, spatial planning, nature conservation and development etc.

What are the difficulties for realizing cross border maps?

1. Technical difficulties (see working group B).

2. Absence of a legal obligation to cooperate on flood mapping cross border. As a result the success of joint projects depends on (individual) personal relations and willingness to cooperate. If a key person leaves the organization, this can frustrate the cooperation process for a long time. In most river basins however, bilateral agreements appear to exist, but not always on the regional/local level.

3. a. Regional authorities often lack sufficient power (in terms of money and mandates) or political will (interests) to choose for cooperation in general and cooperation on flood mapping in specific. From the experts point of view the benefits might be clear but realizing cross border maps depends mainly upon the power and will of the regional authority. b. Another, related, obstacle is that there can be a difference in power level and/or interests between the cross border counterparts. This means that even if one side of the border chooses for cross border flood mapping, cooperation of the other side is not assured.

4. On either side of the border different (soft) values may exist, depending on for example historical background, religion, world view. This can form an obstacle for cross border flood mapping, for example when relating to the definitions of ‘damage’ or ‘sensitive areas’.

Related to this issue are:


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- the differences in interest between upstream and downstream areas: it is not clear how to make the solidarity principle concrete;

- the sense of urgency of flood risk management may differ on either side of the border, resulting in differences in political will.

Responsibilities

1. The decision to make cross border flood maps should be taken on the national level. It has to be an agreement between member states. But the implementation is a regional/local matter. On that level the users and definitions of maps have to be identified.

2. Open question: is there a role for the private sector? In the working group there is no agreement on the role that for example insurance companies can play in making flood maps.

How to get cross border flood maps

1. The Water Framework Directive (WFD) and Flood Directive prescribe coordination cross border without specifying it. In order to specify coordination, (a.o) the obligation for making cross border maps should be integrated and specified in the WFD river basin plans that have to be formulated before 2009. Open question: do the WFD river basin management plans provide space for this type of obligation?

2. An accessible inventory (database) of experiences in cross border flood mapping, comparable with EXCIMAP, will be a valuable starting point for realizing cross border flood maps.

3. Cross border mapping might be a valuable tool for other sectors too, for example for noise, air quality, spatial development etc. Broadening the scope of cross border mapping, may lead to an increase of willingness to do it.

6 Conclusions for the FLAPP Policy Working Group and for the EXIMAP Project

The discussion and writing sessions lead to valuable results and statements. Those being relevant for the FLAPP policy working group and the EXIMAP project are summarized, thematically grouped and presented as follows.

Good Practice Examples: - Rhein-Atlas (www.rheinatlas.de) - Sachsen-Atlas (http://www.umwelt.sachsen.de/de/wu/umwelt/lfug/lfug-

internet/wasser_13888.html) - TIMIS - OderRegio (www.oderregio.org) - ELLA (www.ella-interreg.org) - SAFER (www.EU-SAFER.de)

Good reasons for cross border flood mapping: - In Europe the solidarity principle is broadly accepted. For water management this

resulted for example in the river basin management approach (Framework Directive, draft Flood Directive). Taking this serious means that flood maps of joint river sections across borders should at least fit together (same starting points, same data etc.). So it


Page 35

is not necessary that there is one map (type) available for a whole river basin, but border sections should match.

- Cross border cooperation in making flood maps of border areas is more cost effective. For examples expensive techniques like laser scanning are relatively cheaper if the border area is scanned at once instead of separately by two countries.

- In the case that on either side of the border domestic areas are situated (like the example Görlitz/Zgorzelec) common flood maps will be a starting point for efficient emergency and calamity management (plans) across borders.

- Cross border flood maps can be trigger for common measures in the border region. They provide a common basis for an integrated cross border approach of flood risk management, spatial planning, nature conservation and development etc

- Cross border mapping might be a valuable tool for other sectors too, for example for noise, air quality, spatial development etc. Broadening the scope of cross border mapping, may lead to an increase of willingness to do it.

- the process of cross-border flood mapping can strengthen transnational co-operation and exchange between responsible authorities

- the process of cross-border flood mapping can help to increase confidence between the concerned countries and to reduce mistrust is existing

Users of flood maps and their demands - It is not possible to name users in general; lists that have been produced could be

used as checklists to start the process but in each project a specific participation process is necessary.

- The user groups have to be identified and should participate in the processes as soon as possible.

- The demands of different users will always be different for each user group and for each river basin or region.

- Especially for cross border mapping projects the time should be taken to discuss the demands jointly and to conclude with joint approaches for a whole river basin.

- Standard catalogues like aimed at in EXIMAP can help to start the participation procedures. But the general lists will not substitute an individual process.

- User participation raises the identification and the acceptance of the results. It should start in an early stage of the project.

Flood Mapping Process:

Demands on input data - regulations allowing a free access to existing data from authorities are needed - for all data metadata-information (in accordance with ISO) must be provided - all geo-information must be available in digital form - a same data-format is not necessary

Demands on methods - Statistic data shall be used for run-off derivation if available - run-off “MUST” be harmonized to avoid different water level calculation in border areas - scenario definitions in space and time shall become state of the art for all future

mapping projects including duration of a high water level in a specific location - The use of either a 1D- or 2D models for water level calculation depends on the river

characteristics and the vulnerability of the study area

Demands on products


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- a complete backflow of digital products developed during the mapping process should become standard

- final results shall be validated by local authorities to increase acceptance - maps shall be provides in hard-copy versions as well as WebGIS/Web Service - a standard map design is not necessary

Possibilities of dissemination - development of user specific web services, - active promotion of hazard maps by authorities, - dissemination can be realized separated: dissemination for experts and dissemination

for citizens (specific web interfaces), - production of brochures to advert for the map products and possible access-points, - - see examples from all presentations

7 Outlook

FLAPP, weitere Workshops oder Konferenzen?

Annexes 1. List of Participants 2. Program 3. Presentations (List / snap shot CD ROM PDF) 4. Charts of results (Photos)


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Annex 1 - List of participants


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Annex 2 - Program

21.9.2006 12:30 – 17:30

12:30 -13:00 Arrival and registration of participants

13:00 Welcome and introduction to workshop programme (André Freiwald, Saxon Flood Centre)

Session I: Introduction to flood mapping

13:15 Basic concepts, terminology and overview of mapping activities in Europe (Peter Heiland, Infrastruktur und Umwelt)

13:45 Process of flood mapping – examples from the „Oder Flood hazard maps“ (Jürgen Neumüller, Infrastruktur und Umwelt)

14:20 Coffee break

Session II: Cross border flood mapping – obstacles and solutions

14:40 TIMIS: Example from the Mosel River (Ivo Leiss, Ernst Baseler & Partner)

15:00 Pilot cross border flood map Görlitz/Zgorzelec (André Freiwald, Saxon Flood Centre)

15:20 Experiences from the Rhine/Elbe-Atlas (Peter Zeisler, Rodriguez + Zeisler + Blank; André Assmann geomer GmbH)

15:40 Break

16:00 Discussion:

- “Do´s” and “Don’t`s” in processing flood maps

- How to overcome obstacles in cross border flood mapping

17:15 Conclusions of 1st day + introduction to 2nd day

17:30 Closure 1st day

19:30 Dinner

22.9.2006 9:00 – 13:00

9:00 Opening second day (André Freiwald/ Peter Heiland)

Session III: Flood maps as a tool for improving flood preparedness

9:05 Flood maps for the Stendal County in Saxony–Anhalt (Germany) (Manuela Gretschel, UAS Magdeburg-Stendal)

9:25 NOAH/ FLIWAS (Kees de Gooijer, HKV)


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Discussion/ writing session – Input for EXCIMAP and the joint approach of the FLAPP Network

9:45 EXCIMAP - Towards recommendation on best practice on flood mapping (Frédérique Martini)

10:05 Coffee break

10:30 Introduction to writing session (André Freiwald/ Peter Heiland)

10:40 Writing session

- “Do`s and Don’t`s” in processing and using flood maps

- How to overcome obstacles in cross border flood mapping

11:30 break

11:45 Writing session (continue)

12:45 Conclusions

13:00 Closure


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Annex 3 - Presentations

The following presentations can be found on the accompanying CD-ROM as pdf-file.

File Name: 01_Session1_Opening_Freiwald.pdf

File Name: 02_Session1_Flood Mapping in Europe_Heiland.pdf

File Name: 03_Session1_Process of Flood Mapping_Neumueller.pdf

File Name: 04_Session2_TIMIS_Leiss.pdf

File Name: 05_Session2_Pilot Cross-Border Flood Map_Freiwald.pdf


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File Name: 06_Session2_Experiences from the Rhine-Elbe

Atlas_Zeisler_Assmann.pdf

File Name: 07_Session3_Flood Maps for Stendal County_Gretzschel.pdf

File Name: 08_Session3_NOAH-FLIWAS_de Gooijer.pdf

File Name: 09_Discussion_EXCIMAP_Martini.pdf

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