Sub-Report Phase 2: Flood Risk Mapping in the Elbe River Basin. Authors: Kristina Rieth, Kai Deutschmann Version 30 September 2011

Transcription

1 Sub-Report Phase 2: Flood Risk Mapping in the Elbe River Basin Authors: Kristina Rieth, Kai Deutschmann Version 30 September 2011

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3 Content 1 Introduction Work plan phase 2 for the river basin Elbe Issues Activities Outputs River basin pilot team Meetings of the river basin pilot team Involvement of stakeholders Existing information at each side of the border Models and available data Available flood hazard and risk maps Available maps in Brandenburg and Saxony Maps in Czech Republic Shown information of the flood hazard and risk maps Saxony Brandenburg Significance of flood hazard and risk maps for the region Maps in Saxony Maps in Brandenburg Older maps Recent maps Comparison across the border Similarities and differences in approaching flood risk mapping Obstacles to be overcome for harmonization of flood risk maps or joint flood risk mapping in cross border region Recurrence Land use Water depth Expected benefits of (joint) cross border cooperation for flood risk maps Results of the joint cross border mapping Knowledge Exchange Interregional transfer Study visit flood protection measures Information and examples about cross border mapping Information and examples of flood protection measures Page 1

4 5.1.4 Synopsis of the criteria of significance Lessons learnt Conclusions Potential ways to harmonise flood risk mapping methods Suggestions for themes to be discussed during the next partner meeting: demands (remaining questions) and offers (good practice) Demands Offers Page 2

5 1 Introduction 1.1 Work plan phase 2 for the river basin Elbe To support the realisation of the objectives a work plan for phase 2 was written by the project partners in October 2010 and published on the extranet. It is reproduced as Annex 1. In April 2011 the Workplan has been actualised including the first activities of phase 3 (Annex 2) Issues For the phase 2, Inventory Flood Risk Mapping, the pilot team shares the following aims: Agreement on the objectives and benefits of flood risk mapping Inventory of existing flood hazard and risk maps on both sides of the borders between Brandenburg Saxony and Saxony/Germany Czech Republic Discussing experience with flood risk mapping and cross border cooperation Discussing priorities for joint flood risk mapping on both sides of the border Brandenburg Saxony Exchange on the experiences made with flood risk mapping and cross border cooperation with other project partners Activities Contracting with external experts for FHM, FRM and FRMP in Brandenburg and Saxony and for hydro numeric modelling in the pilot area 7 river basin meeting to discuss the above mentioned issues Writing inventory report on flood risk mapping 2 stakeholder meetings to present and discuss the results with the stakeholders Presentation of the results during the 2 nd Partner Meeting in Dresden and Mühlberg Organization and preparation of knowledge transfer meetings which were planned in August and were rescheduled to November Workshop on risk mapping with Povodí Labe and Povodí Vltavy (CZ) Outputs The outputs of phase 2 of the Project FLOOD-WISE are described below and will be presented at the 3 rd project partner meeting in Cluj-Napoca (RO). 1.2 River basin pilot team After the Launch Conference in Brussels the project partners in Brandenburg and Saxony started up the FLOOD-WISE project by establishing the river basin team Elbe and defining its tasks and objectives. The river basin team and its objectives are described in the Sub-Report of phase Meetings of the river basin pilot team The first regional river basin meeting was held on 23 June The members of the River basin pilot team and their shared objectives are reported in the Sub-Report of phase 1. Until the 2 nd Project Partner Meeting in Dresden the river basin team met four times during Phase 2 ( , , , ). A fifth meeting was scheduled for but had to be cancelled due to severe transport problems (ice) and was compensated by and phone conferences. Due to the stakeholder meeting on (first scheduled for December 2010) where the results of the PFRA should be discussed the work designated to phase 1 dominated the meetings in But according to the work plan developed during PPM 1 the work on the inventory of risk mapping was despite its secondary role done by the central organisations. The results were introduced to and discussed with the stakeholders. Page 3

6 After the 2 nd Partner Meeting in Dresden there were two regional river basin meetings ( , ). Topics were the data availability, concertation of use of the hydronumerical models and the layout for the FHM and FRM, the inventory of policies, strategies and objectives for the FRMP as well as the preparation of the stakeholder meeting in July and an exchange meeting with partners of the Bug and Somes river basin in August. On 30 th June 2011 there was a meeting with the contractor to present and handover the maps and report of the PFRA. The 8th RBM was held on 19 September 2011 in Dresden. Topics were: status of work in the pilot area, implementation flood risk management plan (Inventory report phase 3), Discussion and concertation Political Statement and the preparation 3rd Partner Meeting in Cluj-Napoca Involvement of stakeholders Until now three meetings with the stakeholders have taken place. Meeting 1 in June 2010 has been reported in the Sub-Report of phase 1. The meeting no. 2 from January 2011 was primarily assigned to the discussion of the PFRA results and towards better knowledge of the organisations and people involved on both sides of the border. These contents are reported too in the Sub-Report of phase 1. During this meeting the printed results of the inventory on Flood Risk Mapping were presented to the stakeholders. Furthermore, the results were used as background for the PFRA thus defining the APSFR. Both were accepted by the stakeholders. The third meeting on 5 th July 2011 took place again in the Town hall of Mühlberg. Invited were 27 people from 24 institutions, of which only six institutions could take part. Topics were the project development and the status of the development of flood maps and of the FRMP for the area. For finding adequate objectives and possible measures for the FRMP, the environmental offices of both states and the contractor will produce drafts of objectives and measures and hand these over to the stakeholders for discussion in the second half of In preparation an overview on target categories was distributed. 2 Existing information at each side of the border In the Sub-Report on phase 1 the data existing on both sides of the border are summarized. The following overviews are based on this description. 2.1 Models and available data Flood Risk Mapping depends on the availability of data. In Table 1 the data currently usable or at use in both states are displayed. Data Free State of Saxony Brandenburg hydrographical network from DIRECTIVE 2000/60/EC topographic maps land use data (ATKIS, CIR) digital terrain model data (1 m grid) 1D and 2D hydrodynamic models for computing water surface profiles determining and displaying inundated areas and flow depths on the basis of digital terrain model data and water surface profiles commissioned commissioned river bed profiles with profiles of hydraulic installations - Page 4

7 Data Free State of Saxony Brandenburg several specialized data that can be used for Flood Risk Maps, e.g. soils concerted flood levels for the Elbe River surveillance network of gauges own or shared hydrological models of floodprone rivers Table 1: Models and available data in both partner states The modelling for Saxon areas has been made in advance of the Floods Directive and the LAWA recommendations 1. So the existing results have to be revised for the common map. For the Elbe in Brandenburg the determination of flood areas with a 2D stationary model for the river channel and the foreland (SOBEK) is commissioned. This model will be used for the revision of the Saxon data as well. 2.2 Available flood hazard and risk maps Flood Hazard Maps are available for the Elbe River in Brandenburg, Saxony and Czech Republic. In Saxony for the main rivers are flood hazard and risk maps available too. In Brandenburg flood risk maps have bee made in a pilot project for the Stepenitz River Available maps in Brandenburg and Saxony Karte der Überschwemmungsgefährdung Elbe Free State of Saxony: X Brandenburg: X Translation: Flood hazard maps Elbe. Scale: 1: Indicators: Inundation areas without flood protection measures, water depths, dikes, industrial plants with raised hazard potential, water treatment plants. Probabilities: 100 and 300 years resp. 1,5 x water level of 100 years probability in Germany. Remarks: Developed in INTERREG IIIB-project ELLA for all states along the Elbe River. Preußische Karte der Überschwemmungsflächen Free State of Saxony: X Brandenburg: X Translation: Prussian map of inundation areas Scale: 1: Indicators: Inundations areas of historical floods, information of topographical map Probabilities: (none) Remarks: In the 1 st decade of the 20 th century drawn for whole Prussia. No complete collection known. To be searched for Brandenburg as source of historical floods. Elbstromwerk Free State of Saxony: X Brandenburg: X Translation: Atlas of Elbe River Scale: 1: Indicators: River, inundations areas differenciated in natural and reduced inundation areas, dikes, coarse information of topographical map Probabilities: (none) Remarks: In the last decade of the 19 th century drawn for the whole Elbe River. Schadenpotenzialkarte ELLA Free State of Saxony: X Brandenburg: - Translation: Damage potential maps. Scale: 1: Indicators: Inundation areas without flood protection measures, potential economic damage Probabilities: 100 and 300 years (extreme event) Remarks: Developed in INTERREG IIIB-project ELLA 1 LAWA (German working Group on Water Issues of the Federal States and the Federal Government): Recommendation for the Establishment of Flood Hazard Maps and Flood Risk Maps, 25/26 March 2010, Dresden Page 5

8 Gefahrenhinweiskarte Free State of Saxony: X Brandenburg: - Translation: Risk map atlas Scale: 1: Indicators: Inundation areas without flood protection measures, Potential economic damage [ /m²] Probabilities: 20 (only on the web), 100 and 300 years (extreme event) Remarks: Basis for spatial planning and civil protection Hochwassergefahrenkarte Stepenitz Free State of Saxony: - Brandenburg: X Translation: Flood-hazard-map Stepenitz Scale: 1: Indicators: Inundation area, water depth, water velocity Probabilities: 10, 100 and 200 years Remarks: Drafted in FRMD-pilot-project at river Stepenitz; automatically to be drawn by GISapplication after modelling for the whole state of Brandenburg. Hochwasserrisikokarte Stepenitz Free State of Saxony: - Brandenburg: X Translation: Flood-risk map Stepenitz Scale: 1: Indicators: Inundation area, land usage, inhabitants, hazardous plants, protection areas after FD, cultural heritage (later: monuments), relevant civil infrastructure, flood-protection infrastructure Probabilities: 10, 100 and 200 years Remarks: Drafted in FRMD-pilot-project at river Stepenitz; automatically to be drawn by GISapplication after modelling for the whole state of Brandenburg. Hochwassergefahrenkarte Free State of Saxony: X Brandenburg: - Translation: Flood-hazard-map Scale: 1:5.000 and 1: Indicators: Inundation area, water depth Probabilities: 20; 50; 100 and 200/300 years Remarks: Developed within the Saxon flood control concepts for each local community Hochwasserrisikokarte Free State of Saxony: X Brandenburg: - Translation: Flood-risk-map Scale: 1:5.000 and 1: Indicators: Inundation area, land use, affected inhabitants, IPPC installations, protection areas Probabilities: 20; 100 and 200/300 years Remarks: for the flood risk maps the data of the flood control concepts were processed, a publication on papers isn t foreseen, but the display as web service. Überschwemmungsgebiete 100a (1) S. 1 BbgWG Free State of Saxony: - Brandenburg: X Translation: Inundation areas determined per law in Brandenburg Scale: Textual determination Indicators: Inundation areas, dikes and elevated earth-surface Probabilities: 100 years Remarks: In par. 100a subparagraph 1 sentence 1 of the Water Act of Brandenburg areas between rivers and dikes or elevated land are determined as inundation areas. Because of the clear definition no map is needed to visualise these. Karte festgesetzter Überschwemmungsgebiete Free State of Saxony: - Brandenburg: X Translation: Map of legally defined inundation areas Scale: GIS-information, printed in 1: (not published, accessable on demand) Indicators: Inundation areas, dikes and information of topographical map Probabilities: 2, 10 and 100 years Remarks: Expert-based interpretation of inundation areas legally defined in the former GDR as textual determination only (with exceptions in several districts where maps exist). Überschwemmungsgebiete 100a (1), (3), (5) SächsWG and 32 WHG (1) Translation: Inundation areas determined per law in Saxony Scale: 1: Free State of Saxony: X Brandenburg: - Page 6

9 Indicators: Inundation areas Probabilities: min. 100 years Kommunale Hochwasserinformationskarte Free State of Saxony: X Brandenburg: - Translation: Municipal flood information map Scale: 1:5.000 Indicators: Inundation areas, information about endangered objects, infrastructure and crisis management Probabilities: 20; 50; 100 and 300 years Remarks: Developed for the towns of Glauchau, Meißen, Radebeul and Torgau within INTER- REG IIIB-project ELLA, for the cross-border cities of Goerlitz (D) and Zgorzelec (PL) within INTERREG IIIC-project FLAPP Kommunale Gefahrenzonenkarte Free State of Saxony: X Brandenburg: - Translation: Municipal hazard zone map Scale: 1:5.000 Indicators: Intersection of intensity and frequency of a flood event (hazard level diagram) Probabilities: 20; 50; 100 and 300 years Remarks: Developed for the towns of Glauchau, Meißen, Radebeul and Torgau within INTER- REG IIIB-project ELLA, for the cross-border cities of Goerlitz (D) and Zgorzelec (PL) within INTERREG IIIC-project FLAPP The maps produced or designed 2009 or later do follow the recommendations of the LAWA, published in Maps for special areas, e.g. the Elbe flood of 1845 in Saxony between the borders with CR and Brandenburg, or maps for special flood events exist as well. Especially the Elbe flood of 2002 has been visualised many times. A viewer showing the extend of the inundation areas can be found on the internet (copy and paste in browser address; Mühlberg should be in the center of the map): +to...&layer=all_cities&layer=communities&layer=river_network&layer=flooded_ar- EAS&zoom_rect_minx=109&zoom_rect_miny=10&zoom_rect_maxx=452&zoom_rect_maxy=392&zoom_x=&zoom_y=&mo ve_x=&move_y=&cmapsize=&clanguage=&imgbox= &mapext=&zoom=2&map=mfelbe2002&imgxy= &imgext= &cmdp=zoom_rect&scalep= &minXp= &minYp= &cellSize= &mapimage.x=449&mapimage.y= Maps in Czech Republic 2 Flood hazard maps Flood Hazard maps in the Czech Republic show the flood extent (Figure 1), water depth (Figure 2), water velocity (Figure 3) and flood intensity. The flood hazard maps which show the flood extent are the basic documents. They were developed and maintained according to legislative instructions and show administratively determined areas. Flood extent maps are available for a minimum number of scenarios: Q5, Q20, Q100. There is a lack of data for water depth and inundation areas for some events. The implementation of the Flood Directive requires an extreme event (>Q100). The Czech Republic will use a Q500 as an extreme event according to the FD, which is still largely being compiled. 2 Sources: Presentations Implementation of The Directive 007/60/EC of the European Parliament and of the Council on the assessment and management of flood risks in the Czech Republic /Dráb, A., Drbal, K., Říha, J./2009; Implementace povodňovésměrnice v ČR / Josef Reidinger, Ministerstvo životního prostředí, LABEL Page 7

10 Figure 1: Example of the layout of the Flood Hazard Maps with flood extent in Czech Republic Figure 2: Example of the layout of the Flood Hazard Maps with water depth in Czech Republic Figure 3: Example of the layout of the Flood Hazard Maps with water velocity in Czech Republic Page 8

11 Evaluation of flood intensity Grid Water depth - h [m] Grid water velocity v [m/s] Grid flood intensity IP [m²/s] Determination of flood danger by using risk matrix Flood intensity [m²/s] Return period [years] Grid flood danger Figure 4: Determination of flood intensity and flood danger Flood risk maps The creation of risk map is done in two steps: the first step is to determine the flood danger. The danger of flooding is a combination of hazard, exposure and probability. The preparation of Czech danger maps is based on the Swiss model, with information with respect to high, medium, low or residual risk of the flood. Page 9

12 The determination of flood intensity is based on the combination of water depth and velocity (Figure 4). Therefore an intensity value at high water (IP) will be calculated. This results in a maximum of two values for each grid point, the highest value of the flood intensity (so-called max. acceptable risk) is displayed in the map. An example of the flood danger maps is shown in Figure 5. Table 2 explains the different zones in the danger map and give recommendations for spatial planning. Figure 5: Example of the layout of the flood danger maps in Czech Republic Category High (red) Medium (blue) Low (orange) Residual (Yellow) Recommendation - Don t permit new structures. - Flood protection measures for existing buildings. - New structures are possible with restrictions. - Sensitive structures are not desirable. - The expansion of current built-up areas is not recommended. - New constructions are possible but land parcel owners must be warned. - Special flood measures for sensitive buildings. - Urban planning taking into account sensitive buildings (health care institutions, fire departments, historical landmarks etc.) Table 2: Categories of Czech flood danger maps After the creation of the flood danger map follows Step 2: the creation of risk maps: Basis of risk maps are: the hazard maps of the Swiss model, the ZABAGED raster data (Fundamental Base of Geographic data) and Page 10

13 land-use plans. The risk map is the intersection of the results of hazard mapping, risk objects and the exposure (in land use plans). It shows the danger and the vulnerability (Figure 6). Figure 6: Example of the layout of the flood risk maps in Czech Republic Figure 7: Example of the detailed layout of the flood risk maps in Czech Republic Page 11

14 In Table 3 the recommended land use in the different danger categories is shown. Category High (red) Medium (blue) Recommended land use - Water area - Parks and open space, garden, woods - Arable land, meadow, pasture land - Sport - Recreation Low (orange) - Residential - Public services - Transportation and utility - Industrial and manufacturing - Agriculture (structures) Residual (Yellow) - Sensitive structures (health care institutions, fire departments, historical landmarks etc.) Table 3: Recommended land use 2.3 Shown information of the flood hazard and risk maps Saxony The hazard maps which were established within the flood protection concepts fulfil the requirements of the Floods Directive. The layout is shown in Figure 7. For the Elbe River there are 5 water depth classes (0 0,5 m, 0,5 1,0 m, 1,0 2,0 m, 2,0 3,0 m, > 3,0 m). For new maps the recommendation of the LAWA will be applied. An example of the design of risk maps referred to the LAWA recommendation is shown in Figure 8. Flood Hazard Map (HQ 100) Figure 8: Example of the layout of the Flood Hazard Map in Saxony Page 12

15 Flood Risk Map (HQ 100) Figure 9: Example of the layout of the Flood Risk Map in Saxony Brandenburg Brandenburg has decided to use a fixed layout of the Flood Hazard Map [FHM] and the Flood Risk Map [FRM]. These designs are shown in Figure 9 and Figure 10. The layout has been determined as mandatory; additional information can be shown on the map but does not appear in the key. Figure 10: Example of the layout of the Flood Hazard Map in Brandenburg. Figure 11: Example of the layout of the Flood Risk Map in Brandenburg (cutout of key). Page 13

16 3 Significance of flood hazard and risk maps for the region Basis for effective flood protection is the creation of target group oriented flood maps. These are adapted to regional planning and civil protection authorities. They contain detailed information on flood plains or damage potentials and recommendations. Discussions with stakeholders have shown that the existence of flood maps isn t always known. But if they know it they would use and consider it as a practical instrument for precaution and prevention. Furthermore a remark of the stakeholders was that the scale of the maps is often too small for the implementation of measures and the disaster management. This should be considered in the creation of new maps. 3.1 Maps in Saxony Flood hazard and risk maps show the areas endangered by flooding. Maps on small scale like the risk map atlas provide an overview of the flooding hazard in the catchment area. To highlight the potential risks that exist, even behind protective measures, observations have been made without considering the effect of existing flood control systems. It shows there is no absolutely certain protection. These maps provide an advice and the basis for prevention measures and precautions of people affected. Maps on large scale are the basis for the realisation of flood protection. They show which areas are threatened with which intensity and probability. On the website of the Saxon Flood Centre 3 the following maps are available: Designated flood areas Flooded areas HQ100 Local hazard maps Atlas of flood hazards (flood and damage potential map) Flooded areas August 2002 So the people can inform themselves about the hazard of flooding. 3.2 Maps in Brandenburg Older maps The oldest maps known so far that are showing flood risks are the Prussian maps of the flood-prone areas. These already show that there is a flood hazard along the Elbe River and its tributaries. In the former GDR the inundation areas of several annualities were legally defined. Unfortunately these definitions were in most cases purely textual. Since these decisions are still juristically binding in Brandenburg a group of experts interpreted the descriptions of the inundations areas and drafted a map. Up to now this map is used as hint towards the existence of a potential inundation area at a special point, thus preparing detailed decisions. The legally defined inundation areas in the region do not declare any terrestrial land near the Elbe as inundation area Recent maps The Water Act of Brandenburg of 2008 determines that areas between rivers and dikes or higher ground are inundation areas. This textual juristical declaration does not need a map, since its borders are clearly defined (river, dike, elevated ground). In the project area in Brandenburg almost all the land surface between the river banks and the dikes is clearly recognisable. The exemption is the part north of Mühlberg resp. the dike southwest of Brottewitz and the dike between Brottewitz and the river where elevated ground and the dams of the state road L67 form the border. 3 Page 14

17 Figure 12: Inundation areas (hazard areas) after legal determination and modelling in ELLA HQext ELLA 48h : inundation area from ELLA modelling after 48 h runtime. The maps from the INTERREG IIIB-project ELLA do have a wider scope since the underlying modelling excludes the flood protection system. These maps clearly demonstrate that there is a considerably high flood hazard not only in the legally defined inundation areas but further to the east and north. Additionally, the results of the PFRA show that there is a significant risk potentially arising from floods in the region. This information defines a wide part of the postglacial valley of the project area in Brandenburg as potentially under flood hazard. Because of the amount of vulnerable objects in this area there also is a considerable flood risk. The legally defined inundation areas and the inundation areas from ELLA are shown in Figure 11. Page 15

18 4 Comparison across the border 4.1 Similarities and differences in approaching flood risk mapping A detailed comparison of the maps of both states is given in Annex 3. If compared both map layouts from Saxony and Brandenburg show the inundation areas with their corresponding water depths for both a flood with a medium (annuality of 100 years) and a low probability (annuality of 200 years). The Saxon FHM additionally shows areas behind dikes as areas endangered by floods, a category not used in Brandenburg up to now but scheduled for usage in the future. The FHM from Saxony shows many details of the flood protection system whereas the maps from Brandenburg will not show the protection system in detail. The FHM are almost similar in the usage of the scale of the underlying maps (Brandenburg also prepares a map with underlying plots of land). The annualities of the floods are also comparable for the medium and low probability, whereas Saxony uses an annuality of 25 years and Brandenburg one of 10 years as flood with high probability. Comparable as well are the model results displayed in the hazard maps. The layout of the FRM from Brandenburg shown in Figure 10 is currently under revision. All of the contents shown in the FRM from Saxony will be shown in the future map from Brandenburg too. Brandenburg displays two flood probabilities in the FRM and additionally shows the cultural heritage as well. The FRM are identical in the underlying topographic maps (see FHM), the method for computing the number of people potentially affected, the potentially affected installations and protected areas and the treatment of transported sediments (not shown). Differences appear in the categories that will be used from ATKIS, the official map information system in Germany, and the other potentially relevant information where Brandenburg displays the sewage treatment plants below the PRTR-value as well. 4.2 Obstacles to be overcome for harmonization of flood risk maps or joint flood risk mapping in cross border region Recurrence The display of the hazards and risks of a flood with a high probability will be possible since both states will have comparable data. But in Saxony the floods with high probability are defined as flood with an annuality of 20 years whereas Brandenburg has decided to define a flood with an annuality of 10 years as flood with high probability. The partners have decided to use HQ10 in the common cross border map. Hazard maps are instruments for flood prevention and disaster management. The water level at a 10- years event is in the range of the alarm level 4 or above. Therefore a HQ10 should be shown in the hazard map. Saxony-Anhalt, where the Elbe River further flows through, also works with a HQ10 in a pilot project on the tributary Weiße Elster. In contrast HQ20 is represented as a frequent event as a flood with a high probability in Czech Republic. Since both events (HQ10, HQ20) occur within the dikes, there should be no difference in the inundation area. The difference in water depth is between 78 cm at the gauge Schöna and 50 cm level at the gauge Torgau. In Brandenburg no detailed fixation of inundation areas in the region has been accomplished yet. The inundation areas, which define the hazard areas, are either defined textually or are based on a 2D quasi-instationary modelling using a DTM with a 25 x 25 m grid. In August 2011 a new model for the project area shall be finished based on a 1 x 1 m grid and using a 2D stationary method. By using these modelling results, that use the same design flood as the modelling made for the Saxon area, it should be possible to develop common cross-border maps Land use The differences in the usage of ATKIS-data on land-use will not lead to a disharmony in the FRM. Both states will show the relevant categories recommended by the LAWA but there may be differences in the data used in the background. Page 16

19 The work on the PFRA has shown that until recently there were no usable data on the cultural heritage. Brandenburg has decided to extent this beyond the cultural world heritage onto monuments. Their locations have been digitalised or mapped completely by 15 th August. Both the concerted method for the PFRA and the risk mapping and the recommendations of the LAWA demand the consideration of monuments. Brandenburg is testing the usage of POI for navigation systems and the assignment of coordinates onto the monuments via GIS address data. Each has its advantages but has to be harmonisable with the data from Saxony. Additionally Brandenburg is thinking of using the locations of archives and museums together with monuments and the cultural world heritage. In an area with comparably low populations and settlement density these four categories seem to reflect the the cultural heritage well Water depth Brandenburg has divided the results on water depths in four depths classes, whereas Saxony uses four borders (5 classes). The LAWA recommends the division into 5 classes. Brandenburg follows this recommendation insofar as a fourth depth border (0,5 1 m m) is being calculated but not automatically printed on the map. Since these borders are comparable a harmonised map should be possible. Be caused of the fact that the modelling for Saxon areas have been made in advance of the LAWA recommendations, the data for Saxony have a border at a water depth 3 m while a border at 4 m is recommended. 4.3 Expected benefits of (joint) cross border cooperation for flood risk maps Until now the modelling of the flood in each state starts with the definition of a hydrograph that normally is concerted with the neighbouring states. After that a model stays in the area of each state and stops at the borders where the results again will be discussed with the neighbours. These should accept the modelling results and use them accordingly. But this method does not pay attention to hydraulic streams that can result from blocks in the neighbouring area and thus has to be inaccurate. For example may the deflection caused by the curve of the Saxon dike at the Elbe near Staritz lead to a higher water level in the Brandenburg area near Brottewitz than this can be detected with the inputhydrograph alone. Cross-border cooperation could develop a common model detecting this or could lead to concerted models considering this. Or, if ways of financing could be found, a shared model readily showing these points, could be developed. Another advantage of cross-border modelling could be the automatically consideration of the benefits of retention measures installed on one side of the border at the other side. The models used at the Elbe today do not consider retention results but design flood protection measures based on concerted water levels that were fixed without the retention areas already installed or under planning. The advantage of this strategy is the plus in security that is gained by flood protection measures that are higher than necessary. The disadvantage lies in the possibly unbalanced economy of flood protection. At least cross-border cooperation in modelling and the development of flood hazard and flood risk maps lies in the alleviating way of consideration the measures of flood risk management taking place on one side of the border at the other side. Especially if a joint hydro numeric (2D, instationary) model is used the results of hydraulically relevant measures would be incorporated automatically in the maps. 4.4 Results of the joint cross border mapping For the pilot area Elbe near Mühlberg a 2D calculation for the river channel is possible by using the data from the Technical University of Dresden. This data cover the Saxon inundation area as well and allow results according to the defined standards for the project. It was planned to use the 1D model of the German Federal Institute of Hydrology (BfG) in Brandenburg and the available inundated area and water depth in Saxony in the pilot area. But the 1D Model of the BfG was not sufficient, since the usage of 1D-data of the river bed would lead to an unnecessarily coarse 2D-model of the flow channel and additional calculations for the Saxon area were not possible by this approach. Together with the Saxon Water Reservoir Administration the partners decided that the contractor of Brandenburg shall generate a new 2D Model for the pilot area by using the data from the Technical Page 17

20 University of Dresden additionally. The DTM for Brandenburg will in the border area be coupled with the DTM of Saxony. With the decision about the hydro numeric modelling the missing water depth at 4m and the flow velocity indicators in Saxony will be produced too. The joint flood hazard map is shown in Annex 4, the flood risk map in Annex 5. 5 Knowledge Exchange 5.1 Interregional transfer Study visit flood protection measures Donor region: Benefiting region: Elbe River Basin all Partner River Basins During the Partner Meeting project partner 7 and 8 organised for all partners a study visit concerning flood protection measures along the Elbe River in Brandenburg and Saxony Information and examples about cross border mapping Donor region: Benefiting region: Elbe River Basin Somes/Szamos River Basin Project partner 7 sent a working paper about flood hazard mapping in Saxony, which was written for the exchange in FLOOD-WISE. The first part of it is a summary how the hazard maps after the flood 2002 were developed. The Saxon General guidelines for using the hazard maps are the source of the most information. The described procedure was not developed for the implementation of the Flood Directive. But these maps are the basis for the preparation of hazard maps and risk maps in the implementation of the FD. The described cross border maps of Görlitz and the Elbe-Atlas were not developed within the framework of the floods directive. So the maps do not correspond to the Flood Directive or the Saxon flood control concepts. These are separate products, just two examples of cross border mapping. An exchange meeting on risk mapping between the partner of the Somes and the Elbe river basin was planned from 18 th to 19 th August 2011 in Dresden. Due to many appointments of the Romanian partners the meeting had to be rescheduled short-term to November Information and examples of flood protection measures Donor region: Benefiting region: Elbe River Basin Bug River Basin During the PPM 2 in Dresden the Bug River basin requested an exchange about flood protection measures with the Elbe RB. Partners 7 and 8 decided to place this in Brandenburg at the river Oder/Odra. Since the information and examples about cross border mapping mentioned above (5.1.2) was of interest to Bug RB too we proposed to combine both exchanges in one week, first at the Oder in Brandenburg, then in Saxony. The first part of this exchange has been scheduled for 15 th to 17 th August and was organised by partner 8. Due to several problems with the time limits of the three partners at the Bug RB this exchange has been rescheduled to November Page 18

21 5.1.4 Synopsis of the criteria of significance Donor region: Benefiting region: Elbe River Basin Rur River Basin Project partner 8 sent a Synopsis of the criteria of significance to PP Lessons learnt The work in the pilot area shows that cooperation and coordination within a river basin are of overriding importance and should take place at an early stage. Beneficial was the use of existing harmonised policies and strategies, standards and data. The work already done by the ICPER and the River Area Association (FGG) Elbe eases the cross-border implementation of the FD strongly. Additionally methodological recommendations like they are prepared by national (LAWA) or international organisations and projects (ELLA, LABEL) support the development of shared maps. 6 Conclusions 6.1 Potential ways to harmonise flood risk mapping methods In the case of the basic hydronumeric modelling Brandenburg has developed its own binding demands for the channels, the banks and the foreshore areas (interlinked 1D/2D modelling, stationary; measures to be modelled 2D instationary). Especially at the expected potential inundation area of the Elbe near Mühlberg this will be changed towards a completely 2D stationary modelling. The model which is currently under development will be adjusted to the existing model for the river used by the Federal Institute of Hydrology (in fact it uses the same DTM for the channel) and its results will be adapted to the findings in Saxony. The way used here is harmonisation of the basic hydraulic information by harmonising the models. Additionally both the Flood Hazard Maps and the Flood Risk Maps use many data that were already chosen during the PFRA. In this first step both the data and their assessment has been harmonised. The information that will be used besides the PFRA-data are the potentially affected protected areas identified in Annex IV(1)(i), (iii) and (v) to Directive 2000/60/EC and the gauges. Of the potentially affected protected areas the areas designated for the abstraction of water intended for human consumption bodies of water designated as recreational waters areas designated for the protection of habitats or species have been notified after the WFD (data sets parea ). The gauges have also been notified after the WFD (data set swstn ). Since these information is available no auxiliary harmonisation is necessary. The way used here is harmonisation of the basic land-use information by harmonising the data sets that shall be used for the maps. The reason behind the harmonisation of the data sets is that the LAWA has recommended common objectives and methods for the development of the maps which were adapted by all the states in the river basin Elbe. The way used here is harmonisation of the strategy for the development of the maps. The case of the different use of ATKIS-data by both partners that will not lead to differences in the maps shows another way of harmonisation: In the maps data will be generalised, e.g. as Areas with special functions. For that it will not be necessary that the data behind this supra-category are the same as long as they are sub-categories. Page 19

22 6.2 Suggestions for themes to be discussed during the next partner meeting: demands (remaining questions) and offers (good practice) Demands The FD contains only few hints towards possible measures. The work of WG F did not lead to a thorough and comprehensive list of possible measures so far. The next partner meeting could be used to put the different lists of measures from the six river basins and compile a common list. Or the strategies used by the several partners of how to develop measures could be presented and discussed Offers The basic way to harmonise the objectives and methods used in Germany is the development of recommendations in an informal organisation of the German states and the federal administration, the LAWA. The three German partners can offer to introduce the LAWA recommendations on mapping too. The LAWA recommendations can be a suitable manual also for international river basins. Saxony owns a Software called INGE that can easily be used by municipalities as tool for disaster prevention and management. The Saxon state office offers to demonstrate this software to anyone interested. Brandenburg has ordered to develop a GIS-Module usable with ESRI ArcGIS for easing data management and the printing of the maps. We offer to introduce this module to anyone interested. Brandenburg uses a plausibility check procedure on the preliminary results of the hydraulic modelling. This checking procedure was basically developed by the German state of Baden-Wuerttemberg. It adds the momentum of a reality check to the calibration and validation procedures known in modelling and offers the advantage that conclusions of the plausibity-checked results should be indisputable afterwards. By this way the maps produced with this checked results do earn more confidence by everyone involved in the mapping and planning process. We offer to introduce this plausibility check. Page 20

23 Annex 1: Work plan 2 Elbe: period 11/ /2011 Inventory studies on flood risk mapping Identifying issues: Agreement on the objectives and benefits of flood risk mapping Priorities for joint flood risk mapping on both sides of the border Discussing experience with flood risk mapping and cross border cooperation Planning: November-January 2010 Output: a) Commonly defined objective and expected benefits of phase 2 b) Top 5 of priorities regarding preliminary flood risk mapping c) Identified obstacles and knowledge gaps and good practices for cross border cooperation Activities: 3 rd Regional River Basin Meeting ( ): 1) Status of the common tender procedure for the pilot project 2) Discuss the objectives of flood risk mapping for the cross-border region 3) Discuss the threats and challenges related to flood risk mapping 2 nd Stakeholder Meeting (middle of December 2010): 1) Introduction and status of the project 2) Discuss local priorities 2 nd Regional River Basin Meeting with CR (January 2011): 1) Identify differences, similarities and common objectives within the implementation of the FD 2) Consider flood risk management in more detail in a border area 3) Discuss and define the expected benefits of the project 4 th Regional River Basin Meeting (January 2011): 1) Status of the pilot project 2) Preparation of the Sub-Report: a. Discuss the objectives, the threats and challenges related to flood risk mapping and prioritize them b. Identify obstacles, knowledge gaps and good practice concerning flood risk maps and cross border cooperation Planning: February 2010 Output: Draft-inventory report Activities: - Write the report about the results of the regional river basin meetings: problems and good practices on flood risk mapping - Discuss the draft-report with the members of the river basin team - Send the draft inventory report to the Shared Service Center Planning: March 2010 Output: Final inventory report Activities: - Complete the inventory report after SKYPE Meeting with RBC - Send the final inventory report to the Shared Service Center Annex Page 1

24 Annex 2: Work plan 3 Elbe: period 04/ /2011 Joint cross border flood risk map Joint cross border inventory on flood risk management planning Identifying issues: 1) Development and collection of data relevant for flood hazard and risk mapping 2) Development of a joint layout of the maps 3) Draft of the maps, concertation of their content with the stakeholders, printing 4) Inventory on policies, strategies and general objectives in the region 5) Joint appropriate objectives in the region Planning: April - July 2011 Output: d) Work Plan 3 (period 04 9/2011) e) Data sets ready for mapping f) Joint layout of FHM and FRM g) Plausibility-checked hydro numeric model for Brandenburg h) Inventory for FRMP i) Appropriate objectives for the pilot area Activities: Contracting with External Experts (April/Mai 2011): 4) Binding of contractor and start of hydro numeric modelling in Brandenburg 5) Contractors for FHM, FRM and FRMPs in Saxony 6) Contractors for Coordination in Saxony and Project Management in Brandenburg Development of coordinating and method-defining documents: 1) Overview of data sets to be used in mapping 2) Rules for combination of hydro numeric models from both states 6 th Regional River Basin Meeting (Mai 2011): 1) FHM, FRM: a. Data availability in Saxony and Brandenburg; data formats b. Joint layout c. Contracting on mapping, hydro numeric modelling and coordination/management 2) FRM: Inventory on policies, strategies and general objectives in the region Cooperation with CZ: 4) Inventory of flood risk mapping in CZ for Sub Report FHM/FRM 5) a study about differences resulting of use of HQ 500 vs. HQ 200 as an extreme event is planned Meeting on political commitment (May/June 2011): 1) Introduction of Flood Risk Management 2) Overview of results of PFRA and perspective of mapping 3) Results of the inventory on policies, strategies and general objectives 4) Definition of political objectives for the planning process and the transfer of the results to the public 7 th Regional River Basin Meeting (June 2011): 3) State of work by contractors Annex Page 2

25 4) Rules for combination of hydro numeric models a. Brandenburg Saxony (joint model) b. joint model model of BfG (Federal Institute for Hydrology) 5) Preparation stakeholder meeting 3 rd Stakeholder Meeting (end of June 2011): 3) Status of the project 4) FHM, FRM: a. Introduction to mapping process b. Introduction to and discussion of joint layout 5) FRM: a. Introduction to Flood Risk Management Plans b. Appropriate objectives: - introduction and approval of inventory results - development of joint appropriate objectives Transfer Activities: 1) FHM/FRM: Information of other partners about experiences made in mapping 2) Offer to other partners to introduce to the software developed in Brandenburg and Saxony for mapping and hazard management Planning: July / August 2011 Output: Draft FHM/FRM Activities: - Plausibility check in Brandenburg - Drafting of FHM/FRM - transfer activities (exchange/intervision team/training) 8 th Regional River Basin Meeting (July/August 2011): 1) Result of hydro numeric modelling in Brandenburg; comparison to Saxon model and BfG model 2) Result of plausibility check in Brandenburg 3) Feasibility of the joint layout and start of finalising the FHM/FRM 4) Reporting on mapping Planning: September 2011 Output: a) Final FHM/FRM b) Reports on mapping c) Final Sub Report FHM/FRM d) Inventory Report FRMP Activities: - Finalising FHM/FRM, printing - Development of Saxon, Brandenburg and joint Reports on Maps as part of the FRMP - Writing of Sub report on FHM/FRM - Preparation of PPM 4 in Cluj Transfer Activities: 3) FHM/FRM: Annex Page 3

26 a. Transfer of mapping experiences to other partners b. Documentation of experiences recommend as good practices c. Draft of recommendations on mapping 4) FRMP: a. Introduction of inventory on objectives b. Introduction of political commitment process c. Introduction of appropriate objectives in the region Annex 3: Implementation of Art. 6 of the Flood Directive in Saxony and Brandenburg Article 6, sect. 3 and 4: Flood Hazard Maps Aspect Scale of presentation Scale of preparation Presented scenarios: (a) low probability (b) medium probability (c) high probability Flooded areas and indication of intensity: a) the flood extent; b) water depths/ level c) flow velocity or the relevant water flow Free State of Saxony 1: : a) HQ200 or HQ300 b) HQ100, c) HQ20 or HQ25 a) yes b) yes c) relevant water flow (m/s *h) Brandenburg 1: and 1: : a) HQ200 b) HQ100 with impact of protection measures (dikes) c) HQ10 a) yes b) yes c) flow velocity Czech Republic 1:10:000 1: a) HQ 500 without protection measures b) HQ 100 c) HQ 20 a) yes b) yes c) flow velocity Annex Page 4

27 Article 6, sect. 5: Flood Risk Maps Aspect Free State of Saxony Brandenburg Czech Republic Scales Like flood hazard maps Like flood hazard maps, except of 1:2.500 Like flood hazard maps Potentially affected Indication of affected inhabitants per municipality Indication of affected inhabitants per living space (Intersection of flooded area and populated area - with assumed statistic equal distribution (Intersection of flooded area and ATKIS-populated Area inhabitants percentage) percentage of inhabitants of municipality) Type of economic activity ATKIS DLM data set with categories of use: Urban areas Areas with mixed use Areas with special functions Areas with industry and commerce Traffic areas Green areas and open space Wood Agricultural areas Other areas ATKIS DLM data set with categories of use: 2111 Urban areas 2112 Areas with industry and commerce 2113 Areas with mixed use 2114 Areas with special functions 2122 Disposal site 2127 Transformer Station 2129 Sewage purification plant 2133 Heat supply station 2134 Water supply station 2201 Sports facilities 2202 Leisure facilities 2302 Dump, embankment 2314 Slurry tank, slurry pond, earth digestion basin 3101 Street 3103 Square 3201 Track Railways 3301 Airport 3302 Airfield, landing place 3401 Harbour 3501 Train station 3514 Bridge, over- / undercrossing 4101 Cultivated Area 4102 Grassland 4107 Wood, forest 4109 Arable Crop Urban areas Areas with mixed use Community, Public Areas Technical infrastructure Traffic areas Production and Storage areas Recreation and Sports facilities Gardens Single Objects Annex Page 5

28 Aspect Free State of Saxony Brandenburg Czech Republic Installations which might cause accidental pollution in case of flooding Indication of installations as referred to in Annex I to Council Directive 96/61/EC (1 Symbol) Area declarations for areas with drinking water refuge, mineral springs, bathing waters and other protected areas identified in Annex IV(1)(i), (iii) and (v) to Directive 2000/60/EC (WFD) Indication of installations as referred to in Annex I to Council Directive 96/61/EC PRTR-Register Area declarations of areas with drinking water refuge, mineral springs, bathing waters and other protected areas identified in Annex IV(1)(i), (iii) and (v) to Directive 2000/60/EC (WFD) Indication of transported sediments Other sources of pollution No no No Yes (sewage treatment plant below PRTR-value) Annex Page 6