SEVERE FLOODING IN THE MIDDLE EAST LEBANON

JANUARY 4, 2013

Walter Hays, Global Alliance for Disaster Reduction, Vienna,

Virginia, USA 

AFTERMATH OF WINTER STORM CAUSES FLOODING THAT

LEAVES FOUR DEAD AND CLOSES SCHOOLS THROUGHOUT COUNTRY

FLOODING IN LEBANON

FLOODING IN LEBANON

PHYSICAL EFFECTS OF FLOODSPHYSICAL EFFECTS OF FLOODS

INUNDATION, HIGH-VELOCITY FLOW, HIGH-VOLUME DISCHARGE, EROSION, AND

SCOUR

INUNDATION, HIGH-VELOCITY FLOW, HIGH-VOLUME DISCHARGE, EROSION, AND

SCOUR

DAMAGE FROM DAMAGE FROM INUNCATIONINUNCATION

DAMAGE FROM DAMAGE FROM INUNCATIONINUNCATION

A SCENARIO INTEGRATES PHYSICAL EFFECTS AND A SCENARIO INTEGRATES PHYSICAL EFFECTS AND SOCIETAL IMPACTS TO DETERMINE RISKSOCIETAL IMPACTS TO DETERMINE RISK

A SCENARIO INTEGRATES PHYSICAL EFFECTS AND A SCENARIO INTEGRATES PHYSICAL EFFECTS AND SOCIETAL IMPACTS TO DETERMINE RISKSOCIETAL IMPACTS TO DETERMINE RISK

EROSION, SCOUR, AND EROSION, SCOUR, AND LANDSLIDESLANDSLIDES

EROSION, SCOUR, AND EROSION, SCOUR, AND LANDSLIDESLANDSLIDES

LOSS OF LOSS OF FUNCTIONFUNCTIONLOSS OF LOSS OF FUNCTIONFUNCTION ECONOMIC LOSSECONOMIC LOSSECONOMIC LOSSECONOMIC LOSS

RISKRISKRISKRISK

SOCIETAL IMPACTS OF FLOODSSOCIETAL 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

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

VULNERABILITY ASSESSMENT FOR

FLOODS

WHAT INCREASES VULNERABILITY

MANKIND’S ACTIONS AND NATURAL EVENTS CAN CHANGE THE

VULNERABILITY OF ELEMENTS AT RISK TO FLOODS, A PART OF THE WATER

CYCLE

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 CONTRIBUTIONAn 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.

MANKIND’S ACTIONS THAT CHANGE SOME PART 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 CHANGE SOME PART OF THE 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.

LOSS OF FUNCTION OF STRUCTURES IN FLOODPLAIN

FLOODSFLOODS

INUNDATION

INTERACTION WITH HAZARDOUS MATERIALS

STRUCTURE & CONTENTS: DAMAGE FROM WATER

WATER BORNE DISEASES (HEALTH PROBLEMS)

EROSION AND MUDFLOWS

CONTAMINATION OF GROUND WATER

CAUSES OF RISK

CAUSES OF RISK

DISASTER LABORATORIES

DISASTER LABORATORIES

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.