Flood Control Measures and Their Impact on the Environment

1. 10th Eco-Junior-Expert ProjectHuman activity and Its impact on the environment Group III Flood Control Measures

2. Names and nations • Student from Poland: Zawistowski Aleksy, Wiecheć Bartlomiej, Dziadek Michal, Chrapek Pawel • Student from Austria: Auer Theresa, Schlager David, Taschl Ines • Student from Czech Republic: Formánková Andrea, Háva Lukáš, Ištok Tomáš, Poborská Anna, Sokolík Jakub, Šimánková Eva, Urbanová Zuzana, Krebsová Lenka, Hruška Martin, Nováková Tereza, Novotná Dagmar, Novotná Tereza • Student from Hungary: Nagy Alex, Mészáros Richárd, Nagy Gábor, Kóder Kinga

3. Task • Measuring the flow rate of different rivers • The Lužnice River • The Nežárka River • The Blatský Brook

4. Floods

5. Flood control measures • As a prevention against floods are used river channel reconstruction and the environs. • Two alternative methods exist:mobile and fixed barrier. • Dry polder Krkavec • Polder is dry reservoir , which retains high water. • Two variants of the construction of dry polder are decided.

6. Variant 1 • Culmination flow Decreasing of the effect • Twenty years flood Q20 = 189 m3/s → 51 % • Fifty years floodQ50 = 253 m3/s → 55% • One hundred years floodQ100 = 315 m3/s → 55%

7. Variant 2 • Culmination flow Decreasing of the effect • Twenty years flood Q20 = 189 m3/s → 24 % • Fifty years flood Q50 = 253 m3/s → 14% • One hundred years floodQ100 = 315 m3/s → 9%

8. Calculation of data • Calculation of revolutions in time • Calculation of the speed of the water flow • Making profiles of the rivers

9. How we measured • Special instrument: current meter • Method:measure width of the river Allocation Measure flow rate Calculation

11. Results of the Nežárka river Profile of the river  Rotations per minute 

12. Results of the Blatský Brook Profile of the river  Rotations per minute 

13. Lužnice: Profile of the river

14. Lužnice: Rotations per minute

15. Speed of the Blatský Brook

16. Speed of the Nežárka river

17. Speed of the Lužnice river

18. Comparison: our results with the results from CHMI (= Czech Hydrometeorogical Institute)

19. Summary • Our results are coresponding with average rates meassured by CHMI. • In 2002, the high water striked also Veselí nad Lužnicí and this flood was the most severe flood recorded in the history. During the floods 415 houses were flooded (that is, 40 % of the area of this city was flooded). In Veselí nad Lužnicí the floods repeated in 2006.

20. Flood control measures • In Veselí nad Lužnicí flood control measures will be implemented in 2009 and this project will be finished in 2011. • As a prevention against floods are used river channel reconstruction and the environs. Two alternative methods exist:mobile and fixed barrier. • The mobile barriers are installed just before the flood starts. The mobile barriers are constructed from sand-bags and mobile dikes. • The fixed barriers are firmly connected to bedrock.

21. Thank you for your attention…