FLOODS IN REPUBLIC OF GEORGIA June 13-15, 2015 Walter Hays, Global Alliance for Disaster...
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Transcript of FLOODS IN REPUBLIC OF GEORGIA June 13-15, 2015 Walter Hays, Global Alliance for Disaster...
FLOODS IN REPUBLIC OF GEORGIA
June 13-15, 2015
Walter Hays, Global Alliance for Walter Hays, Global Alliance for Disaster Reduction, Vienna, Virginia, Disaster Reduction, Vienna, Virginia,
USA USA
REPUBLIC OF GEORGIA
The heavy rain that began shortly before midnight Sunday caused a
landslide that blocked what is normally a pleasant stream in Tbilisi,
a hilly city, but as the floodwaters grew in strength, a fierce torrent
broke through.
14 DEAD; 40 HOMES DESTROYED
PHYSICAL EFFECTS OF FLOODS
INUNDATION, HIGH-VELOCITY FLOW, HIGH-VOLUME DISCHARGE, EROSION, AND SCOUR
LOSS OF FUNCTION OF STRUCTURES IN FLOODPLAIN
FLOODS
INUNDATION
INTERACTION WITH HAZARDOUS MATERIALS
STRUCTURAL/CONTENTS DAMAGE FROM WATER
WATER BORNE DISEASES (HEALTH PROBLEMS)
EROSION AND MUDFLOWS
CONTAMINATION OF GROUND WATER
CAUSES OF RISK
FLOOD DISASTER LABORATORIES
FLOODING IN TBILISI
FLOODING IN TBILISI
TYPICAL IMPACTS OF FLOODS
DAMAGE TO CONTENTS, LOSS OF FUNCTION OF BUILDINGS AND INFRASTRUCTURE, RELEASE OF
HAZARDOUS MATERIALS, TRANSPORTATION OF DEBRIS, AUTOS, AND HOUSES, ENVIRONMENTAL DEAD ZONES,
AND DISEASE VECTORS
SITING AND BUILDING ON UNSTABLE SLOPES
LANDSLIDES
SOIL AND ROCK SUCEPTIBLE TO FALLS
SOIL AND ROCK SUCEPTIBLE TO TOPPLES
SOIL AND ROCK SUCEPTIBLE TO LATERAL SPREADS
SOIL AND ROCK SUSCEPTIBLE TO FLOWS
PRECIPITATION THAT TRIGGERS SLOPE FAILURE SHAKINGGROUND SHAKING THAT
TRIGGERS SLOPE FAILURE
CAUSES OF DAMAGE
GLOBAL DISASTER LABORATORIES
ATYPICAL IMPACT: ANIMALS ESCAPE FROM TBILISI ZOO
TBILISI: TRANQUILIZED HIPPO
RECAPTURING THE HIPPO
WHAT INCREASES VULNERABILITY
MANKIND’S ACTIONS AND NATURAL EVENTS CAN CHANGE THE VULNERABILITY OF ELEMENTS AT RISK
TO FLOODS
An element’s vulnerability (fragility) is the result of a
community’s actions or nature’s actions that change some part of the
regional water cycle (e.g., precipitation, storage, runoff, transpiration, evaporation).
MANKIND’S CONTRIBUTION
An element’s vulnerability (fragility) is the result of flaws that enter during the planning, siting, design, and construction
of a community’s buildings and infrastructure.
ACTIONS THAT CAN CHANGE KEY PARTS OF THE WATER CYCLE
• Urban development or industrial development in areas that were formerly wetlands.
• Locating buildings and infrastructure in a river floodplain.
MANKIND’S ACTIONS THAT CHANGE SOME PART OF THE WATER CYCLE
• Actions that increase or decrease river gradients (deforestation, dams, etc).
• Actions that change the runoff pattern or rate (e.g., the city’s concrete footprint)
NATURE’S ACTIONS THAT CAN CHANGE THE NORMAL WATER CYCLE
• A flash flood.• Ice jams/ice dams on the river• Rapid melt of snow and ice• Extreme or prolonged
precipitation caused by stalled low-pressure systems.
POLICY POLICY ADOPTIONADOPTION
RISK ASSESSMENT
• VULNERABILITYVULNERABILITY
• EXPOSUREEXPOSURE
• EVENTEVENT
POLICY ASSESSMENT
• COSTCOST
• BENEFITBENEFIT
•CONSEQUENCESCONSEQUENCES
FLOOD RISK ASSESSMENT LEADS TO FLOOD RISK ASSESSMENT LEADS TO FLOOD-DISASTER-RISK REDUCTIONFLOOD-DISASTER-RISK REDUCTION
FLOODSFLOODS EXPECTED EXPECTED LOSSLOSS
A RISK ASSESSMENT
• A risk assessment involves the probabilistic integration of:
• The hazard (e.g., floods) and their potential disaster agents (inundation, erosion, etc) that are directly related to the location of the community and what happens in the regional water cycle.
RISK ASSESSMENT (Continued)
• The location of each element of the exposure in relation to the physical demands of the hazard (i.e., inundation, etc.)
RISK ASSESSMENT (Continued)
• The exposure (e.g., people, and elements of the community’s built environment), represents the potential loss when the natural hazard occurs.
RISK ASSESSMENT (Continued)
• The vulnerability (or fragility) of each element comprising the exposure when subjected to the potential disaster agents.
REQUIRED INFORMATION
• Physical characteristics of the regional drainage system.
• Physical characteristics of each river system and its floodplain.
• Physical characteristics of the regional water cycle.
REQUIRED INFORMATION
• Physical characteristics of catchment basins, reservoirs, and wetlands in the region.
• Physical characteristics of dikes, levees, and dams controlling water discharge and flooding in the region.
REQUIRED INFORMATION
• The hazardous materials located in the floodplain.
GEORGIA’SGEORGIA’S
COMUNITIESCOMUNITIESDATA BASES DATA BASES AND INFORMATIONAND INFORMATION
HAZARDS: GROUND SHAKING GROUND FAILURE SURFACE FAULTING TECTONIC DEFORMATION TSUNAMI RUN UP AFTERSHOCKS
•FLOOD HAZARDS MAPS•INVENTORY•VULNERABILITY•LOCATION
RISK ASSESSMENTRISK ASSESSMENT
RISK
ACCEPTABLE RISK
UNACCEPTABLE RISK
FLOOD DISASTER FLOOD DISASTER REDEUCTIONREDEUCTION
•PREPAREDNESS•PROTECTION/PREVENTION•EARLY WARNING•EMERGENCY RESPONSE•RECOVERY/RECONSTRUCT.
POLICY OPTIONSPOLICY OPTIONS
DISASTER-RISK REDUCTION POLICES FOR FLOODS
MITIGATION, PREVENTION, PREPAREDNESS, FORECASTS AND
WARNING, EVACUATION, EMERGENCY RESPONSE, RECOVERY AND
RECONSTRUCTION, AND EDUCATIONAL SURGES