LESSONS LEARNED FROM PAST NOTABLE DISASTERS MEXICO PART 1: FLOODS

1. LESSONS LEARNED FROM PAST NOTABLE DISASTERSMEXICOPART 1: FLOODS Walter Hays, Global Alliance for Disaster Reduction, Vienna, Virginia, USA 

2. MEXICO

3. NATURAL HAZARDS THAT HAVE CAUSED DISASTERS IN MEXICO FLOODS GOAL: PROTECT PEOPLE AND COMMUNITIES SEVERE WINDSTORMS EARTHQUAKES HIGH BENEFIT/COST FROM BECOMING DISASTER RESILIENT VOLCANIC ERUPTIONS ENVIRONMENTAL CHANGE GLOBAL CLIMATE CHANGE

4. Natural Phenomena that Cause Disasters Planet Earth’s atmospheric-hydrospheric-lithospheric interactions create situations favorable for FLOODS

5. CAUSES OF NOTABLE FLOODS IN MEXICO THE ANNUAL RAINEY SEASON RAINFALL FROM THE ANNUAL TROPICAL STORMS AND HURRICANES BEFORE, DURING, AND AFTER THEY MAKE LANDFALL ON THE GULF COAST OR THE PACIFIC COAST

6. THE SPECIFIC WEATHER SYSTEM DEFINES THE RISK PARAMETERS

7. HIGH POTENTIAL LOSS EXPOSURES IN A FLOOD Entire communities; People, property, infra-structure, business enterprise, government centers, crops, wildlife, and natural resources.

8. FLOODS IN MEXICO’S STATES OF TABASCO AND CHIAPAS WORST FLOODING IN 50 YEARS 1 MILLION PEOPLE ADVERSELY AFFECTED ONE OF THE WORST NATURAL DISASTERS IN MEXICO’S HISTORY NOVEMBER 1-2, 2007

9. FLOODS IN MEXICO: NOVEMBER 1-2, 2007

10. ANNUAL FLOODING IN TABASCO • Mexico’s state of Tabasco has a history of annual floods during November. • Many of Tabasco’s low-lying neighborhoods, such as Villahermosa, the state capital, have become accustomed to living with water in the first floor of their residence for six months of every year.

11. 70 PERCENT OF TABASCO STATE UNDER WATER: NOV 2, 2007

12. 80 PERCENT OF VILLAHERMOSA, TABASCO’S CAPITAL, FLOODED

13. 70 PERCENT OF TABASCO STATE UNDER WATER: NOV 2, 2007

14. SOCIETAL IMPACTS IN TABASCO • Nearly all services in Villahermosa were shut down. • Thousands clung to roofs of houses or waited inside water-soaked houses or designated shelters, waiting to be rescued or to receive emergency assistance. • Elevated parking structures were turned into temporary shelters because many houses were unsafe.

15. SOCIETAL IMPACTS IN TABASCO • After a week of rain in October-November 2007, the Grijalva River rose 2 m (7 feet) above flood stage and overflowed, along with other regional waterways. • Approximately 80 percent of Villahermosa and 70 percent of Tabasco were under water. • 900,000 houses were flooded. • Potable water supplies were exhausted.

16. SOCIETAL IMPACTS IN THE STATE OF CHIAPAS • Tabasco’s neighboring state of Chiapas, which is also flood-prone, experienced extensive flooding in November 2007. • 100,000 people were adversely affected and faced the same problems as in Tabasco state.

17. A GLOOMY FORECAST • More rain was forecast for the heavily drenched region. • With food and drinking water scarce, and some 300,000 of the 1,000,000 still cut off from rescuers, the conditions for serious medical problems such as cholera and other water-borne diseases increased dramatically.

18. FLOODING ASSOCIATED WITH HURRICANE DEAN AUGUST 21, 2007

19. IMPACTS IN MEXICO • Hurricane Dean’s storm surge flooded Ciuidad del Carmen, a town of 120,000, with waist deep sea water. • Heavy rainfall accompanying Dean caused rivers to rise rapidly throughout the region.

20. CHETUMAL: FLOODING AFTER “DEAN” ON AUGUST 21, 2007

21. BACALAR: FLOODING AFTER “DEAN” ON AUGUST 21, 2007

22. IMPACTS REACH SOUTH TEXAS • The impacts in Mexico and South Texas were mainly flooding and landslides associated with and exacerbated by the runoff from the heavy rainfall accompanying the storm.

23. THE ALTERNATIVE TO A FLOOD DISASTER ISFLOOD DISASTER RESILIENCE

24. FLOOD HAZARDS • PEOPLE & BLDGS. • VULNERABILITY • LOCATION • PREPAREDNESS • PROTECTION • EARLY WARNING • EMERGENCY RESPONSE • RECOVERY and • RECONSTRUCTION FLOOD RISK POLICY OPTIONS ACCEPTABLE RISK RISK UNACCEPTABLE RISK GOAL: FLOOD DISASTER RESILIENCE MEXICO’S COMMUNITIES DATA BASES AND INFORMATION HAZARDS: GROUND SHAKING GROUND FAILURE SURFACE FAULTING TECTONIC DEFORMATION TSUNAMI RUN UP AFTERSHOCKS

25. A FLOOD RISK ASSESSMENT HELPS GUIDE POLICY ADOPTION AND IMPLEMENTATION

26. DAMAGE FROM INUNDATION EROSION, SCOUR, AND LANDSLIDES LOSS OF FUNCTION ECONOMIC LOSS A FLOOD RISK ASSESSMENT INTEGRATES PHYSICAL EFFECTS AND SOCIETAL IMPACTS TO DETERMINE RISK RISK

27. CAUSES OF RISK LOSS OF FUNCTION OF STRUCTURES IN FLOODPLAIN INUNDATION INTERACTION WITH HAZARDOUS MATERIALS STRUCTURE & CONTENTS: DAMAGE FROM WATER FLOODS WATER BORNE DISEASES (HEALTH PROBLEMS) DISASTER LABORATORIES EROSION AND MUDFLOWS CONTAMINATION OF GROUND WATER

28. FLOOD DISASTER RISKS DAMAGE TO CONTENTS, LOSS OF FUNCTION OF BUILDINGS AND INFRASTRUCTURE, RELEASE OF HAZARDOUS MATERIALS, TRANSPORTATION OF DEBRIS, AUTOS, AND HOUSES, ENVIRONMENTAL DEAD ZONES, AND WATER BORNE DISEASES

29. 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.

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

31. 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.

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

33. UNDERSTANDING VULNERABILITY: THE ULTIMATE DRIVER OF RISK

34. EVENT VULNERABILITY FLOOD HAZARDS EXPECTED LOSS EXPOSURE PEOPLE STRUCTURES PROPERTY ENVIRONMENT INFRASTRUCTURE Vulnerability: The Driver of Risk

35. An element’s vulnerability (fragility) is the result of a community’s actions or of nature’s actions that change some part of the regional water cycle (e.g., precipitation, storage, runoff, transpiration, evaporation).

36. WHAT INCREASES VULNERABILITY MANKIND’S ACTIONS AND NATURE ITSELF CAN CHANGE THE VULNERABILITY OF ELEMENTS AT RISK TO A FLOOD, A PART OF THE REGIONALWATER CYCLE

37. MANKIND’S CONTRIBUTIONAn element’s vulnerability (fragility) is the result of flaws that enter during the planning, location, siting, design, and construction of a community’s buildings and infrastructure.

38. 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.

39. 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 rate or pattern (e.g., the city’s concrete footprint)

40. NATURE’S ACTIONS THAT CHANGE 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 weather systems.

41. REQUIRED INFORMATION FOR A COMPREHENSIVE VULNERABILITY ASSESSMENT

42. REQUIRED INFORMATION • Physical characteristics of the regional water cycle and drainage system. • Physical characteristics of each river system, its tributaries, and its floodplains.

43. 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 potential in the region.

44. REQUIRED INFORMATION • The hazardous materials and other elements located in the floodplain.

45. CAUSES OF DISASTER LOSS OF FUNCTION OF STRUCTURES IN FLOODPLAIN INUNDATION INTERACTION WITH HAZARDOUS MATERIALS STRUCTURAL/CONTENTS DAMAGE FROM WATER FLOODS WATER BORNE DISEASES (HEALTH PROBLEMS) CASE HISTORIES EROSION AND MUDFLOWS CONTAMINATION OF GROUND WATER

46. A DISASTER is --- --- the set of failures that overwhelm the capability of a community torespond without external help  when three continuums: 1)  people, 2) community (i.e., a set of habitats, livelihoods, and social constructs), and 3) complex events (e.g., floods, earthquakes,…) intersect at a point in space and time.

47. Disasters are caused by single- or multiple-event natural hazards that, (for various reasons), cause extreme levels of mortality, morbidity, homelessness, joblessness, economic losses, or environmental impacts.

48. THE REASONS ARE . . . • When it does happen, the functions of the community’s buildings and infrastructure can be LOST for long periods.

49. THE REASONS ARE . . . • The community is UN-PREPARED for what will likely happen, not to mention the low-probability of occurrence—high-probability of adverse consequences event.

50. THE REASONS ARE . . . • The community is UN-PREPARED for what will likely happen, not to mention the low-probability of occurrence—high-probability of adverse consequences event.