Universität für Bodenkultur Wien University of Natural Resources and Life Sciences Revised flood risk assessment: Quantifying epistemic uncertainty emerging from different sources and processes Dissertation for obtaining the doctorate degree Dr.nat.techn. Submitted by: Dipl.-Ing. Clemens Neuhold Supervised by: o.Univ.Prof.Dipl.-Ing.Dr.techn.Dr.h.c. Hans-Peter Nachtnebel Reviewed by: Prof.Dr.rer.nat.habil.Dr.-Ing. Bruno Merz September, 2010 “I know that I know nothing” Socrates (c.469/470 B.C.-399 B.C.) Content Content Figures ........................................................................................................................... ii Tables .............................................................................................................................iv Acknowledgements .........................................................................................................v Abstract ...........................................................................................................................1 Kurzfassung ....................................................................................................................3 Introduction ....................................................................................................................5 Objectives and thematic outline ...................................................................................10 Uncertainty analysis .....................................................................................................21 Neuhold, C., Stanzel, P.,& Nachtnebel, H. P. (2009): Incorporating river morphological changes to flood risk assessment: uncertainties, methodology and application..................21 Environmental flood risk assessment ..........................................................................45 Neuhold, C.; Nachtnebel, H.P.(2010a): Assessing flood risk associated with waste disposals: methodology, application and uncertainties. ......................................................45 Neuhold, C.; Nachtnebel, H.P. (2009): A qualitative approach to assess flood risk associated with landfills .......................................................................................................61 Laner, D.; Fellner, J.; Brunner, P.H.; Neuhold, C.; Kolesar, C. (2008): Environmental Relevance of Flooded MSW Landfills in Austria..................................................................78 Economic flood risk assessment...................................................................................92 Neuhold, C., Nachtnebel, H.P. (2008): Flood risk assessment in an Austrian municipality comprising the evaluation of effectiveness and efficiency of flood mitigation measures. ..............................................................................................................................92 Schanze, J.; Hutter, G.; Penning-Rowsell, E.; Nachtnebel, H. P.; Meyer, V.; Königer, P.; Neuhold, C.; Harris, T.; Kuhlicke, C.; Olfert, A. (2008): Evaluation of Effectiveness and Efficiency of non-structural measures in Flood Risk Management ............................108 Individual flood risk assessment ................................................................................125 Neuhold, C., Nachtnebel, H.P. (2010b): Reducing life-threatening conditions during extreme flood events - Benefits from implementing spillways to dykes..............................125 Results and conclusions .............................................................................................134 Curriculum vitae.........................................................................................................140 Publications.................................................................................................................141 i Figures Figures Fig. 1: Study area: Austria and the Ill river catchment in the west .................................... 26 Fig. 2: Scheme of methodological approach to derive the damage probability of vulnerable utilisations................................................................................................................ 27 Fig. 3: Watershed of the River Ill and its sub-basins .......................................................... 28 Fig. 4: Derivation of scenarios for hydrologic input variation........................................... 30 Fig. 5: Upper and lower sediment input boundary condition for the River Alfenz............. 32 Fig. 6: Derivation of scenarios for sediment input variation.............................................. 33 Fig. 7: Calculated hydrographs for 100-year rainfall events and distribution of simulated peak values............................................................................................................... 35 Fig. 8: Changes of river bed elevations due to hydrological and sediment input variation37 Fig. 9: Differences of water surface elevations and dyke top edge..................................... 38 Fig. 10: Overtopping probability and height ...................................................................... 39 Fig. 11: Considered sites of MSW landfills and old waste deposits in Austria (AFEA, 2008 a, BMFLUW, 2007) ................................................................................................. 46 Fig. 12: Schematic illustration (Laner et al., 2009) of the procedure to evaluate the flood exposure of waste disposals in Austria, based on the HORA data set (BMFLUW, 2006 b) and site information (AFEA, 2008 a) ......................................................... 48 Fig. 13: Considered case study sites to quantify the possible impacts on waste disposal bodies on a micro scale level (Nachtnebel et al., 2009; BMFLUW, 2007)............. 49 Fig. 14: The Flood Risk Evaluation Matrix (FREM), description of input parameters and threshold levels ........................................................................................................ 53 Fig. 15: Reported sites of MSW landfills in Austria (BMFLUW, 2007) ............................. 64 Fig. 16: Schematic illustration of the procedure to evaluate the flood risk probability landfills in Austria, based on the HORA data set (LANER et al., 2009)................. 65 Fig. 17: Case study sites: (1) Kainach, (2) Salzach, (3) Lech (BMFLUW, 2007) .............. 68 Fig. 18: Description of input parameters and thresholds to the flood risk evaluation matrix ................................................................................................................................. 70 Fig. 19: Evaluation of the flood risk exposure of a landfill site based on the HORA data set ................................................................................................................................. 82 Fig. 20: Flood risk exposure of Austrian MSW landfills (top: based on the number of landfills, bottom: based on landfilled waste volume ............................................... 85 Fig. 21: Portion of “endangered” and “probably endangered” controlled MSW landfills equipped with flood protection facilities ................................................................. 86 Fig. 22: Scenario-based emissions of selected substances during a flood event and under conventional landfill conditions .............................................................................. 88 Fig. 23: Case study area Gleisdorf in the province of Styria.............................................. 93 ii Figures Fig. 24: Development of Gleisdorf 1999 (left) – 2008 (right)............................................. 94 Fig. 25: Calculated expected annual losses based on different enquiry approaches and different states of utilization .................................................................................. 101 Fig. 26: Combined research design with systematization, descriptive and normative approach................................................................................................................ 110 Fig. 27: Three dimensions of strategies for flood risk management (Hutter & Schanze 2008)...................................................................................................................... 120 Fig. 28: Number of people exposed related to a 300-years and 1000-years flood (left). Expected annual losses considering alternative 1 (dyke break and no dyke break), alternative 2 (implemented spillway) and alternative 3 (imposed building ban).. 130 iii Tables Tables Tab. 1: Sensitivity of flood peaks due to input variation for Gisingen (basin outlet) ......... 35 Tab. 2: Evaluation parameters utilised as input to the FREM, grouped in to hydrologic scenarios (columns). Grey shaded fields were compared to pre-defined threshold levels. ....................................................................................................................... 54 Tab. 3: Simulation results of case study 1 including associated risk related colours (yellow: minor risk; yellow/orange: minor to major risk; orange: major risk; orange/red: major to serious risk; red: serious risk) .............................................. 55 Tab. 4: Characteristics of the average potentially endangered controlled MSW landfill and the endangered old MSW landfill ............................................................................ 87 Tab. 5: Considered alternatives and scenarios................................................................... 98 Tab. 6: Cost-Effectiveness Analyses.................................................................................