Flood Loss AssessmentFlood Loss AssessmentAPFM methodologyAPFM methodology
Regional Programme on Disaster Risk Reduction in South East EuropeTraining workshop on flood risk assessment
27 September – 1 October 2010Istanbul, Turkey
Tommaso AbrateClimate and water Department
World meteorologicalorganization
Purposes of an economic assessment
Assess the overall deviation of economic activities from the “normal” course as a result of the flood
Why an economic assessment?
• Assessing net benefits derived from using a flood plain
• Design of appropriate policies and strategies
• Reconstruction planning
• Rescue and emergency coordination
Various phases of flood assessment
Time
Event
Flood risk assessment and policy reform
In-depth evaluation
Early recovery assessment
Rapid assessment
Types of floods
• Flash floods
• Riverine flooding
Sorces of flood losses data
• Actual data collected from historical events– Direct measurements– Water marks,
witnesses, etc
• Potential losses based on stage – damage relationships
Main impact factors
• Depth of inundation
• Flow velocity (esp. flash floods)
• Duration of the inundation
• Timing
• Sediment and pollution load
Stage – damage curve for content and structural damages
Velocity and depth relation as a damage factor
Simulated dyke break: depth
Terminology
• Damages: related to the physical damage of public and private assets (infrastructures, houses, vehicle, etc.) caused by the contact with water
• Losses: broader meaning, including secondary and tertiary losses, including intangible ones (human lives) and “things that could have been”
Terminology (ctd)
• Direct losses
• Indirect losses
• Tangible losses
• Intangible losses
Flood losses
Tangible direct losses
Intangible losses
Tangible indirect losses
Primary
Secondary
Tertiary(long term)
Damages to:BuildingsContent of buildingInfrastructures (road, bridges)Crops and animals
Loss and disruption of:Agricultural productionIndustrial productionCommunicationHealth and educationUtility supplies (électricity, gas)
Loss of added valueContamination of water supplyTraffic congestionFood shortagesLoss of income
SalinizationBlack outFire
Stress, Physical and psychological traumaWater borne diseasesIncreased mortality
Loss of lifePhysical injuriesLoss of heritage sites
HomelessnessLoss of livelihoodsPermament loss of unisured possesionBraking of community ties due to displacement or risettlements
Enhanced rate of property decayLong term structural damages
Some business are bankruptReduce GDP
Actual vs potential losses
Rapid assessment during flooding
• Objectives: – Collect factual information for emergency response
and management– Identifying the administrative level concerned
(local, national, international)• Limited time availability, evolving situation
– Casualties, displaced people– Inundation map– Flooded assets– Expected evolution of the event– Assets at risk– Status of lifelines (access roads, hospitals,
electricity, water and food supply, etc.)
Early recovery assessment
• Purpose: – guiding the recovery process and it priorities– designing financial mechanisms
• Evaluation of coping capacity
• Identification of management mistakes
• Focus on tangible and direct losses and on actual costs and damages
Early recovery assessment (ctd)
• Public and private losses
• Who's bearing the losses?
• Magnitude with respect to coping capacity,locally and nationally
• Social aspects of the losses
In-depth assessment
Annual flood losses
Disaggregation of losses by sector
Conclusions
• Collect data before the flood event • Involve local communities • There is not a universal formula for all
contexts• Develop an agreed procedure• Collect data on losses and on who has
to bear them• Compare losses and benefits• Institutional framework for data collection