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FLOODS IN GHANA June 5, 2015 Walter Hays, Global Alliance for Disaster Reduction, Vienna, Virginia, USA Walter Hays, Global Alliance for Disaster Reduction,

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Presentation on theme: "FLOODS IN GHANA June 5, 2015 Walter Hays, Global Alliance for Disaster Reduction, Vienna, Virginia, USA Walter Hays, Global Alliance for Disaster Reduction,"— Presentation transcript:

1 FLOODS IN GHANA June 5, 2015 Walter Hays, Global Alliance for Disaster Reduction, Vienna, Virginia, USA Walter Hays, Global Alliance for Disaster Reduction, Vienna, Virginia, USA

2 EARLY REPORTS OF SOCIETAL IMPACTS OF THE FLOODS, FIRE, AND EXLOSION A PROLONGED SEASONAL RAIN STORM CLOSURE OF ROADS AND SERVICES POWER OUTAGE FAULTY GENERATOR CAUSED FIRE AND EXPLOSION 150 DEAD FROM FLOODING, FIRE, AND EXPLOSION 60 REQUIRED HOSPITAL TREATMENT

3 FLOODS ARE A PART OF GHANA’S NATURAL WATER CYCLE

4 ACCRA: JUNE 29, 1959: 22 CM (7 ½ IN) PARALYZES CAPITAL

5 GHANA IS IN WEST AFRICA

6 GHANA (ACCRA IS THE CAPITAL)

7 ACCRA: THE CAPITAL

8

9 The Red Cross of Ghana provided blankets, mats and drugs to residents in Accra and the six other communities affected by the 2015 flooding, fire, and explosion.

10 Officials blamed the losses from the floods on people building homes and businesses within the city’s waterways, blocking natural drainage systems.

11 TOWARDS FLOOD RISK ASSESSMENT AND RISK REDUCTION Officials: 59, 68, 71, 2015, …We have to stop flood disasters from happening again

12 PHYSICALEFFECTSPHYSICALEFFECTS ELEMENTS OF RISK EXPOSUREEXPOSURE VULNERABILITYVULNERABILITY LOCATIONLOCATION RISKRISK

13 PHYSICAL EFFECTS OF FLOODS INUNDATION, HIGH-VELOCITY FLOW, HIGH- VOLUME DISCHARGE, EROSION, AND SCOUR

14 DAMAGE FROM INUNCATION AN ASSESSMENT INTEGRATES PHYSICAL EFFECTS AND SOCIETAL IMPACTS TO DETERMINE RISK EROSION, SCOUR, AND LANDSLIDES LOSS OF FUNCTION ECONOMIC LOSS RISKRISK

15 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

16 VULNERABILITY ASSESSMENT FOR FLOODS

17 Vulnerability: A Vital Part of Risk Assessment FLOOD HAZARDS EVENT VULNERABILITY PEOPLE STRUCTURES PROPERTY ENVIRONMENT INFRASTRUCTURE EXPOSURE EXPECTED LOSS

18 WHAT INCREASES VULNERABILITY MANKIND’S ACTIONS AND NATURAL EVENTS CAN CHANGE THE VULNERABILITY OF ELEMENTS AT RISK TO FLOODS

19 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).

20 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.

21 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.

22 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 )

23 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.

24 LOSS OF FUNCTION OF STRUCTURES IN FLOODPLAIN FLOODS 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 DISASTER LABORATORIES

25 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.

26 RISK ASSESSMENT (Continued) The location of each element of the exposure in relation to the physical demands of the hazard (i.e., inundation, etc.)

27 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.

28 RISK ASSESSMENT (Continued) The vulnerability (or fragility) of each element comprising the exposure when subjected to the potential disaster agents.

29 POLICY ADOPTION RISK ASSESSMENT VULNERABILITYVULNERABILITY EXPOSUREEXPOSURE EVENTEVENT POLICY ASSESSMENT COSTCOST BENEFITBENEFIT CONSEQUENCESCONSEQUENCES FLOOD RISK ASSESSMENT LEADS TO DISASTER-RISK REDUCTION FLOODSFLOODS EXPECTED LOSS

30 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.

31 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.

32 REQUIRED INFORMATION The hazardous materials located in the floodplain.

33 DISASTER-RISK REDUCTION POLICES FOR FLOODS MITIGATION, PREVENTION, PREPAREDNESS, FORECASTS AND WARNING, EVACUATION, EMERGENCY RESPONSE, RECOVERY AND RECONSTRUCTION, AND EDUCATIONAL SURGES

34 MITIGATION SANDBAGS, ETC

35

36 PREVENTION DAMS, STORM BARRIERS, LEVEES, SPILLWAYS, CATCHMENT BASINS, RESERVOIRS, WETLANDS, ETC

37 THREE GORGES DAM: 2309 M LONG, 190 M HIGH, 15 M THICK

38 FLOOD PREVENTION: LONDON, ENGLAND


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