Central EUropean DIsaster Prevention Forum CEUDIP Cracow - 23 - 24 November 2006 Elbe river Summer flood 2002 WintAuguer floodst 2003 2006 SUMMER FLOOD 2002, WINTER FLOOD 2006 CLIMATE CHANGE? Prof. Dr. rer. nat. habil. Uwe Grünewald Chair of Hydrology and Water Resources Management Brandenburg University of Technology Cottbus German Committee for Disaster Reduction (DKKV) within the International Strategy for Disaster Reduction (ISDR) 1 Central European Disaster Prevention Forum CEUDIP Cracow - 23 - 24 November 2006 Structure 1. What happened in August 2002 on the German part of the Elbe river? 2. The same story again in 2006? 3. Are the floods in 2002 and in 2006 a consequence of climate change? Prof. Dr. rer. nat. habil. Uwe Grünewald Chair of Hydrology and Water Resources Management Brandenburg University of Technology Cottbus German Committee for Disaster Reduction within the International Strategy for Disaster Reduction (ISDR) 2 Elbe flood 2002 - damage assessment Germany Czech Republic casualties: 21 casualties: 15 total damage: first estimations total damage: 22.6 billion €, approx. 3 billion € in the beginning of Nov. 2002 corrected to 9.2 billion €. just from Saxony 6 billion € reported to Brussels approx. 220 000 inhabitants 337 000 inhabitants affected evacuated only in Dresden approx. 35 000 only in Prague about people evacuated 50 000 devastating damage done to many Cultural Heritage monuments all 3 subway lines severely (Zwinger, Art gallery, Semper Opera, affected park of castle Wesenstein) 1. What happened in August 2002 on the German part of the Elbe river? 3 Costs of Flood catastrophies* since 1990 Order Year Area damages in Mio. US$ 1 2005 USA (New Orleans, hurricane Katrina) > 100,000 2 1998 China (Jangtse, Songhua) 30,700 3 1998 China (Jangtse, Yellow River, Huaihe) 24,000 4 2002 South, Central, East Europa (Elbe, Donau) 21,200 5 1993 USA (Mississippi) 21,000 6 1995 Korea 15,000 7 1991 China (Huaihe, Lake Taihu) 13,600 8 1993 China 11,000 11 countries in the Indian Ocean 10,000 9 2004 (Tsunami) … … … … 20 1997 East Europa (Oder) 5,900 21 1998 Central America (Hurrikan Mitch) 5,500 Reference: Münchner Rück, 2005 (* mostly water damages, partly storm damages) 1. What happened in August 2002 on the German part of the Elbe river? 4 Total precipitation [mm], 12th –14th August 2002 5330000 5350000 5370000 5390000 5410000 5430000 5450000 M u Obersteina ld ! e 114 0 00 000 Colditz ! 700 6 567 102 Dresden-Klotsche 5 !! 0 182 198 8 120 8 Berthelsdorf 0 0 ! 4 1 60 Freital E l ! 0 213 be 0000 Tharandt-Grillenburg 5000 6 565 e Burgstaedt ! 5 ld 0 u ! 24 M 84 ! Gohrisch r ! F 91 a e 1 b u r 6 u 109 a e e k 0 2 l i 0 c t i b 0 t w e o Z r G Augustusburg 1 g ! 0 Chemnitz (Wst) e ! 8 ! 1 r 306 00 ! 0 108 M 2 0 000 109 4 0 Einsiedel u 0 300 ! ld 2 6 563 5 e 2 2 120 ! 6 0 00 ! 0 ! 3 250 Stollberg 134 ! ! 2 406 8 0 Rauschenbach 126 0 2 ! 1 229 Marienberg ! 0 195 00 Aue 1000 ! 6100 56 136 5 100 0 Eibenstock 4 ! 1 176 Carlsfeld TS Fichtelberg (Wst) 00 ! ! 00 900 240 202 5900 55 5 5330000 5350000 5370000 5390000 5410000 5430000 5450000 Source: LTV, 11/2002 1. What happened in August 2002 on the German part of the Elbe river? 5 Water level of 9,40 m at gauge Dresden/Augustusbridge exceeded all former levels Foto: Grünewald 2003 1. What happened in August 2002 on the German part of the Elbe river? 6 But: measured discharge of 4580 m³/s is equivalent to a HQ(150) only! 1. What happened in August 2002 on the German part of the Elbe river? 7 Reduced runoff potential in the City of Dresden by aggradation, vegetation, development ... Quelle: Wasser- und Schifffahrtsamt Dresden, 2002 Quelle: DLR, 2002 ... resulted in raising water Foto: Grünewald 2003 level ... ... which could have been partly avoided! 1. What happened in August 2002 on the German part of the Elbe river? 8 Theory ≠ Practice May 2002 1. What happened in August 2002 on the German part of the Elbe river? 9 Flood peak cutting Elbe River near Wittenberge by controlled polders in the Havel lowland 1. What happened in August 2002 on the German part of the Elbe river? 10 Dead fishes in the Havel River after emptying of the Havel polders 11 1. What happened in August 2002 on the German part of the Elbe river? 11 RIVER ELBE FLOOD April 2006 HQ(12) in the Upper Part of the Elbe River in Dresden versus highest water stage in Hitzacker in the Middle and Lower Part of the Elbe River! 2. The same story again in 2006? 12 Snow melt in the Catchment too low for significant flood Example 2005 215 Liter snow equivalent/ m² in the catchment of River Mulde + ca. 150 Liter snow equivalent/m² in the East Ore Mountains ... Quelle: SZ, 15.03.2005 ... resulted in 5.96 m crest in DD ... Quelle: SZ, 28.03.2005 2. The same story again in 2006? 13 Concurrent snow melt and strong precipitation in the catchment of the Upper River Elbe and River Moldau in 2006 ... ... resulted in 7.49 m crest in … with considerable flooding Dresden ... Quelle: SZ, 15./16.04.2006 Quelle: SZ, 01./02.04.2006 2. The same story again in 2006? 14 Comparison of water stages in August 2002 and in April 2006 Highest stages [cm] April 06 August 02 2. The same story again in 2006? 15 Schematic cross section of the Middle River Elbe Floodplain with zones of morphological and ecological importance … between the confluence of R. Mulde and R. Saale into the R. Elbe exists with 117,4 km² the largest coherent floodplain forest area of Central Europe … IKSE, 2005 2. The same story again in 2006? 16 August 2002: Breakdown of dikes „…broke three dikes between Wittenberg/L. and the mounding of R. Mulde. The largest break occurred at Seegrehna, where about 200 m³/s of water flooded 50 km² ...“ Quelle: IKSE, 2005 2. The same story again in 2006? 17 April 2006: No breakdown of dikes but also no river Havel polder retention capacity available Quelle: IKSE, 2005 2. The same story again in 2006? 18 Sedimentation and loss of runoff areas Schleswig-Holstein Mecklenburg-Vorpommern loss in 5 increase in loss in runoff cross sectional Dömitz Location land surface area ! runoff area [m/100years] [%/100 years] Wittenberge [m²/100years] ! 1 0,39 90 7,5 4 2 0,11 129 10,5 Niedersachsen Brandenburg 3 0,59 361 14,3 Berlin 4 0,21 130 6,5 5 0,16 95 3,4 Magdeburg ! Quelle: BAW, 2005 Sachsen-Anhalt 3 Coswig ! 2 Torgau ! 1 Riesa Sachsen ! Thüringen Dresden ! 2. The same story again in 2006? 19 Flood risk management – a interdisciplinary challenge, not to be solved sectorally Spatial measures Constructional measures Risk reduction Reconstruction Behavioural measures r d e e i d s s Information u Reconstruction n a strategies c aid o s t t p i e s o r e n Increase in natural Support for r retention capacity victims technical Disaster flood protection prevention FLOOD EVENT Quelle: DKKV, 2003 2. The same story again in 2006? 20 Risk as resultat of interaction of exposure and vulnerability Potential Men, values, danger environment ... „... the higher described by described by „...the more the probability • intensity •expostion • values set of occurrence probability • value, sensitivity into for an extreme jeopardised event ...“ areas ...“ EXPOSURE VULNERABILITY RisikoRISK ... the higher is the risk! Quelle: DKKV, 2003 2. The same story again in 2006? 21 „... The nature doesn‘t know catastrophies, only men know catastrophies, as far as having survived.“ [Max Frisch: Man in the Holocene, 1979] millennial discharge Call for action for the protection from extreme events …. because of the increasing concentration of values and sensibility against damages and the increasing protection requirement is given also without climate change OcCC, 2003, page 8 2. The same story again in 2006? 22 Are the floods in 2002 and in 2006 a consequence of climate changes ? [SZ, 18.04.2006] Flood protection is climate protection! „M. Platzeck und F. Roßberg; Der Städtetag, 2/2003“ This statement releases us too simply from the responsibility to take care of measures and deficites in FLOOD PROTECTION and FLOOD PREVENTION under unchanged climate conditions! Climate protection is flood protection, too. – J.Trittin; Dresden, 5.7.2003 but does not substitute flood risk management here and today! 3. Are the floods in 2002 and in 2006 a consequence of climate change? 23 20 40 60 0 0 0 0 0 0 0 discharge [m³/s] 1501 1651 3. Are the floods in 2002 and in 2006 1682 1784 1799 1821 1827 1845 1852 1854 1856 y ears 1858 Distribution ofsummer 1860 1862 1864 1866 w i 1868 t 1870 h 1872 re 1874 summer flood last large 1876 co 1878 nstu 1880 1882 1884 1886 cte 1888 1890 d 1892 histori 1894 1896 1898 1900 c y 1902 floods a e 1904 in 1890 l a 1906 v r s 1908 a w 1910 l 1912 u es i th 1914 1916 a ob 1918 nd winter 1920 se a cons 1922 1924 r 1926 v 1928 ati 1930 o 1932 n 1934 equence of climate change? 1936 1938 floods 1940 1942 1944 1946 1948 1950 at the 1952 1954 1956 1958 1960 summ wi 1962 R 1964 n iver Elbe 1966 t e 1968 r floo 1970 er f 1972 l 1974 ood 1976 d 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 24 Every thirtieth year in the “Osterzgebirge” a catastrophe caused by floods ? Date Precipitation Material damage Dead July, 29/30, 140 mm within 24 h destroyed railway lines and at least 1897 in the crest of Ore villages in Gottleuba, Müglitz 8 mountains and Roten Weißeritz valleys, (“Erzgebirge”) and also in Muldetal and in the city of Chemnitz July, 08/09, in couple of hours 110 bridges destroyed, 160 152 1927 200 mm; in the area bridges damaged, 188 of 44 km² in 25 min buildings destroyed.