Lessons Learned from Notable Flood Disasters in New Zealand

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

2. Natural Phenomena that Cause Disasters Planet Earth’s Atmospheric-lithospheric Interactions Cause: • Floods

3. NATURAL HAZARDS THAT HAVE CAUSED DISASTERS IN NEW ZEALAND FLOODS GOAL: PROTECT PEOPLE AND COMMUNITIES WINDSTORMS EARTHQUAKES HIGH BENEFIT/COST PROGRAMS FOR BECOMING DISASTER RESILIENT VOLCANOES ENVIRONMENTAL CHANGE GLOBAL CLIMATE CHANGE

4. ELEMENTS OF RISK AND DISASTER

5. HAZARDS EXPOSURE VULNERABILITY LOCATION ELEMENTS OF FLOOD RISK RISK

6. RUGGED TOPOGRAPHY AND THE WAIMAKARIRI RIVER FLOODPLAIN

7. The combination of torrential rain from summer rain storms and occasional cyclones, and the steep slopes favorable for flash floods leads to opportunities for disaster.

8. FLOOD HAZARDS:ARE POTENTIAL DISASTER AGENTS

9. FLOOD HAZARDS • TOO MUCH WATER DISCHARGED WITHIN THE DRAINAGE SYSTEM TO BE ACCOMMODATED IN THE REGIONAL WATER CYCLE • INUNDATION • EROSION • SCOUR • MUDFLOWS

10. A DISASTER CAN HAPPENWHEN THE POTENTIAL DISASTER AGENTS OF A FLOOD INTERACT WITH THE VULNERABLE BUILT ENVIRONMENTS OF NEW ZEALAND’S COMMUNITIES

11. NEW ZEALAND’S CITIES

12. 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.

13. 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.

14. THE REASONS ARE . . . • When it does happen, the functions of the community’s buildings and infrastructure will be LOST because they are UNPROTECTED with the appropriate codes and standards.

15. 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.

16. THE REASONS ARE . . . • The community has NODISASTER PLANNING SCENARIO or WARNING SYSTEM in place as a strategic framework for concerted local, national, regional, and international countermeasures.

17. THE REASONS ARE . . . • The community LACKS THE CAPACITY TO RESPOND in a timely manner to the full spectrum of expected and unexpected emergency situations.

18. THE REASONS ARE . . . • The community is INEFFICIENT during recovery and reconstruction because it HAS NOT LEARNED from either the current experience or the cumulative prior experiences.

19. NOTABLE FLOOD DISASTERS FEBRUARY 13, 2004

20. FLOOD DISASTER OF 2004 • The flooding began on February 13, when a series of unusual summer storms that brought heavy rain and strong winds to the lower North Island.

21. FLOOD DISASTER OF 2004 • The floods damaged at least 19 bridges, affected water and sewer systems, and knocked out power and communications for several days.

22. FLOOD DISASTER OF 2004 • Instead of being beneficial to agriculture by adding rich soil, the 2004 floods destroyed crops and devastated cattle and sheep farmers.

23. FLOOD DISASTER OF 2004 • As a result of 2004’s flooding, vegetable prices increased more than 200 percent.

24. ECONOMIC LOSS: ESTIMATED AT $200 million.

25. NOTABLE FLOOD DISASTERSSOUTH ISLAND DECEMBER 13, 2011

26. THE CAUSE: FIVE DAYS OF TORENTIAL RAIN • The flood started on 12/13/2011 and ended on 12/17/2011 11:59:59 PM, a duration of 5 days. • This flood was assigned a severity class 2 (i.e. this is an extreme event with an estimated recurrence interval greater than 100 years).

27. IMPACTS The damage was widespread and in some cases spectacular, as walls of water and mud smashed through some houses and across roads, rendering them impassable, but no deaths.

28. DEC. 13 FLOODING

29. DEC. 13 FLOODING

30. DEC. 13 FLOODING

31. THE IMPACTS • More than 100 people were evacuated from their homes. • Collingwood was cut off for three days after a large portion of State Highway 60 was washed away by the one-in-100-year rainfall event.

32. DEC. 13 FLOODING

33. THE IMPACTS • "Nelson and Tasman faced a massive clean-up bill from the destructive torrential downpour, which produced nearly three months' rain in just 24 hours.

34. NOTABLE FLOOD IMAGES

35. HIGH DISCHARGE AFTER A STORM

36. FLOODING: WHAKATANE RIVER

37. INUNDATION

38. CHRISTCHURCH: FLOODING

39. FLOODING: SOUTH ISLAND

40. CYCLONE BOLA PASSED NEAR NEW ZEALAND : MARCH 1988

41. FLOODING AFTER CYCLONE BOLA

42. FLOODING

43. FLOOD INDUCED LANDSLIDE

44. ROAD WASHED OUT

45. NEW ZEALAND’S NEXT FLOOD IS INEVITABLE • ---SO, START IMPLEMENTING MEASURES FOR BECOMING MORE RESILIENT TO A FLOOD DISASTER NOW.

46. THE ALTERNATIVE TO A FLOOD DISASTER ISFLOOD DISASTER RESILIENCE

47. FLOOD HAZARDS • INVENTORY • VULNERABILITY • LOCATION • PREPAREDNESS • PROTECTION • FORECASTS/SCENARIOS • EMERGENCY RESPONSE • RECOVERY and • RECONSTRUCTION FLOOD RISK POLICY OPTIONS ACCEPTABLE RISK RISK UNACCEPTABLE RISK FLOOD DISASTER RESILIENCE DATA BASES AND INFORMATION NEW ZEALAND’S COMMUNITIES HAZARDS: GROUND SHAKING GROUND FAILURE SURFACE FAULTING TECTONIC DEFORMATION TSUNAMI RUN UP AFTERSHOCKS

48. LESSONS LEARNED ABOUT DISASTER RESILIENCE ALL FLOODS PREPAREDNESS FOR ALL OF THE LIKELY FLOOD HAZARDS IS ESSENTIAL FOR DISASTER RESILIENCE

49. LESSONS LEARNED ABOUT DISASTER RESILIENCE ALL FLOODS PROHIBITING THE CONSTRUCTION OF BUILDINGS AND LIFELINE SYSTEMS IN A RIVER FLOODPLAIN IS ESSENTIAL FOR DISASTER RESILIENCE

50. LESSONS LEARNED ABOUT DISASTER RESILIENCE ALL FLOODS EARLY WARNING AND EVACUATION PLANS TO MOVE PEOPLE TO SAFE HAVENS ARE ESSENTIAL FOR DISASTER RESILIENCE