Alliance for Disaster Risk Reduction (ALTER) Project Geghi Reservoir
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Alliance for Disaster Risk Reduction (ALTER) Project WP4: Transfer of Methods Geghi Reservoir and Geghanoush Tailing Dam Break Analysis: Methodology, Software and Data Requirements Prepared by: Alexander Arakelyan, Ph.D GIS and Hydrology Expert Yerevan, Armenia December, 2018 Contents LIST OF TABLES ............................................................................................................................................................ 3 LIST OF FIGURES ........................................................................................................................................................... 4 LIST OF ABBREVIATIONS .............................................................................................................................................. 5 1. INTRODUCTION AND SCOPE OF WORK ................................................................................................................ 6 2. OBJECTS OF THE STUDY ....................................................................................................................................... 7 2.1 WATER RESERVOIR: GEGHI .............................................................................................................................................. 7 2.2 TAILING DAM: GEGHANOUSH ........................................................................................................................................... 7 3. METHODOLOGY ....................................................................................................................................................... 9 3.1 DAM BREACH ANALYSIS ............................................................................................................................................. 9 3.1.1 Dam Failure Types.............................................................................................................................................. 9 3.1.2 Breach Characteristics Analysis ....................................................................................................................... 10 3.1.2.1 Federal Agency Guidelines ........................................................................................................................................... 10 3.1.2.2 Regression Equations ................................................................................................................................................... 11 3.1.2.3 Physically-Based Breach Computer Models ................................................................................................................. 15 3.2 PEAK FLOW EQUATIONS AND ENVELOPE CURVES ............................................................................................................... 17 3.4 TAILING DAM BREACH OUTFLOW CALCULATION ................................................................................................................ 18 3.5 FLOOD MODELING: ONE-DIMENSIONAL AND TWO-DIMENSIONAL HYDRAULIC MODELS ............................................................ 22 3.5 FLUID DYNAMICS: STEADY AND UNSTEADY FLOW ............................................................................................................... 23 3.6 MANNING EQUATION AND N VALUES .............................................................................................................................. 25 3.7 POPULAR MODELS FOR DAM BREAK ANALYSIS AND FLOOD MAPPING .................................................................................... 29 4. REQUIRED DATA FOR DAM BREAK(CH) ANALYSIS AND MAPPING .......................................................................... 33 4.1 HYDRO-METEOROLOGICAL OBSERVATION DATA ................................................................................................................. 33 4.1.1 Meteorological Data ........................................................................................................................................ 33 4.1.2 Hydrological Data ............................................................................................................................................ 34 4.2 ELEVATION DATA AND ITS DERIVATIVES ............................................................................................................................ 35 4.3 LAND COVER ............................................................................................................................................................... 37 4.4 OTHER SPATIAL DATA ................................................................................................................................................... 37 5. DAM BREAK ANALYSIS AND FLOOD MAPPING IMPLEMENTATION......................................................................... 39 5.1 FLOOD HAZARD INDEX CALCULATION ............................................................................................................................... 39 5.2 RIVER MAXIMUM FLOW ANALYSIS .................................................................................................................................. 44 5.3 DAM BREACH MAXIMUM OUTFLOW AND BREACH HYDROGRAPH CALCULATION ...................................................................... 45 6. CONCLUSIONS AND NEXT STEPS ............................................................................................................................ 48 7. REFERENCES ........................................................................................................................................................... 49 ANNEX 1. CALCULATION OF MAXIMUM FLOW OF DEIFFERENT PROBABILITIES FOR GEGHI-GEGHI HYDROPOST ....... 54 ANNEX 2. CALCULATION OF MAXIMUM FLOW OF DEIFFERENT PROBABILITIES FOR GEGHI-KAVCHUT HYDROPOST .. 56 ANNEX 3. CALCULATION OF MAXIMUM FLOW OF DEIFFERENT PROBABILITIES FOR VOGHJI-KAJARAN HYDROPOST 58 ANNEX 4. CALCULATION OF MAXIMUM FLOW OF DEIFFERENT PROBABILITIES FOR VOGHJI-KAPAN HYDROPOST .... 61 ANNEX 5. CALCULATION OF MAXIMUM FLOW OF DEIFFERENT PROBABILITIES FOR GEGHANOUSH-GEGHANOUSH HYDROPOST ............................................................................................................................................................... 64 2 List of Tables Table 1. Possible Failure Modes for Various Dam Types ........................................................................ 10 Table 2. Ranges of Possible Values for Breach Characteristics ............................................................. 10 Table 3. Values of Cb from Reservoir Size ................................................................................................. 14 Table 4. Physically-Based Embankment Dam Breach Computer Models ............................................ 16 Table 5. Summary of the New Erosion Process Models .......................................................................... 16 Table 6. Differences between one- and two-dimensional models .......................................................... 22 Table 7. Manning's n for Channels (Chow, 1959) ..................................................................................... 26 Table 8. Comparison of dam break software ............................................................................................. 30 Table 9. Operational Monitoring Stations within Voghji River Basin ...................................................... 33 Table 10. Annual and monthly average air temperatures in the Voghji River Basin, օC ..................... 34 Table 11. Intra-annual distribution of atmospheric precipitation in the Voghji River Basin, mm ........ 34 Table 12. Cumulative Evaporation in the Voghji River Basin, According to Altitude Zones ............... 34 Table 13. Hydrological Monitoring Posts within Voghji River Basin ....................................................... 35 Table 14. Flow Characteristics in the Hydrological Monitoring Posts within Geghi River Basin ........ 35 Table 15. Classes, Rating and According Weights of FHI Assessment Parameters .......................... 40 Table 16. Classes, Rating and According Weights of FHI Assessment Parameters .......................... 40 Table 17. Maximum Flows of Different Probabilities Calculated for Hydroposts of Voghji River Basin* ............................................................................................................................................................... 44 Table 18. Necessary Input Data for TR-60 and TR-66 Models .............................................................. 45 Table 19. Calculated Values of Geghi Dam Breach Outflow and Timesteps using TR-60 and TR-66 models .............................................................................................................................................................. 46 3 List of Figures Figure 1. Geghi Reservoir ............................................................................................................................... 7 Figure 2. Geghanush Tailing Dam ................................................................................................................. 8 Figure 3. Description of the Breach Parameters ....................................................................................... 11 Figure 4. Data on TSF Failures Compiled by Data in Rico et al. (2008) and Chambers and Bowker (CB) (2017) (Entries in bold are not suitable for analysis) ....................................................................... 20 6 3 Figure