Bulgarian approach for preliminary flood risk assessment

1. Bulgarian approach forpreliminary flood risk assessment Assoc. Prof. Daniela Zlatunova Sofia University “St. Kliment Ohridski”

2. Requirements of Flood Directive • 1. Member States shall, for each river basin district, or unitof management, or the portion ofaninternational river basin district lying within their territory,undertake a preliminary flood risk assessment .

3. Requirements of Flood Directive • 2. Based on available or readily derivable information, suchas records and studies on long term developments, in particularimpacts of climate change on the occurrence of floods, a preliminaryflood risk assessment shall be undertaken to provide anassessment of potential risks. The assessment shall include atleast the following:

4. Requirements of Flood Directive • a description of the floods which have occurred in the pastand which had significant adverse impacts on human health,the environment, cultural heritage and economic activityand for which the likelihood of similar future events isstill relevant, including their flood extent and conveyanceroutes and an assessment of the adverse impacts they haveentailed;

5. Requirements of Flood Directive • an assessment of the potential adverse consequences offuture floods for human health, the environment, culturalheritage and economic activity

6. Approach used for preliminary flood risk assessment

7. Preliminary flood risk assessment based on the past flood

8. Preliminary flood risk assessment based on the past flood • First step - a study of sources and create a chronology of historical floods

9. Preliminary flood risk assessment based on the past flood • There are three cases of historical floods: • historical floods with verbal description of the flood area; • Historical flood with mapped flood area; • Historical flood without information of the flooded area;

10. Preliminary flood risk assessment based on the past flood • I case - River Rositsa /town Sevlievo/ with verbal description of the flooded area Outline the flooded are during the flood invent 1939 with Google Earth

11. Preliminary flood risk assessment based on the past floodGeoreferenced map of the flooded erea during the flood event 1939 – river Rositsa/town Sevlievo/

12. Preliminary flood risk assessment based on the past flood– • Р. Марица – между гр. Пловдив и Първомай • Териториалният обхват на наводнението е документиран на карта в мащаб 1: 250 000. Картата е съставена по данни, събирани на място, веднага след наводнението. Това ни дава основание да приемем, че тя с голяма степен на достоверност отразява действително залетите при наводнението през 1911 г.площи.

13. Preliminary flood risk assessment based on the past floodII case - river Marica between town Plovdiv and town Purvomay with mapped area during the flood event 1911

14. Preliminary flood risk assessment based on the potencial/future/ floodIII case- river Aheloy - no information on flooded area in the past Digital terrain model created based on SRTM- elevation data and river network (blue lines) in the lower reaches of the River Aheloy

15. Preliminary flood risk assessment based on the potencial/future/ flood

16. Preliminary flood risk assessment based on the potencial/future/ flood • Calculating the maximum runoff

17. Preliminary flood risk assessment based on the potencial/future/ flood • hydraulic calculations

18. Preliminary flood risk assessment based on the potencial/future/ flood • Potential flooded area – river Aheloy

19. II.Analysisof the potential risk • Four protected categories to assess the potential flood risk: - human health; - economic activity; - environment; - cultural heritage

20. for human health and economic activity – “the number of affected people”; II.Analysisof the potential risk- Criteria for analyzing flood risk:

21. II.Analysisof the potential risk- Criteria for analyzing the flood risk • For environment; • Sources of pollution under Regulation № 166/2006, European Community; • Protected areas according to Directive on the conservation of natural habitats andof Wild Fauna and Flora/ Directive 92/43/EEC /and according to the Directive on conservation of wildbirds /79/409/EEC/; • Protected water body under Article 119 of the Bulgarian Water Act.

22. II.Analysisof the potential risk- Criteria for analyzing flood risk • For cultural heritage with: • category of "global importance" included in the list of world culturalheritage; • category of "national importance" (archaeological, historical, architectural and ethnographic objects and complexes);

23. II.Aproach for analysingof the potential risk • Put together in GIS – the flood area, the area of settlements, industrial and natural protectionareas an so on….

24. Aproach for analysingof the potential risk

25. III. Identification of the significantflood risk • Criteria for significant flood risk: - number of affected people /more then 15 affected people for the past flood and more then 100 affected people for the future flood/;

26. III. Identification of the significantflood risk • I case – river Rositsa/town Sevlievo/ - 2 976 potentially affected people;

27. III. Identification of the significantflood riskII case – river Maritsa

28. III. Identification of the significantflood risk • III case – river Aheloy • No affected people

29. River sections with significant flood risk

30. Thank you !