LESSONS LEARNED FROM PAST NOTABLE DISASTERS
NEW ZEALANDPART 1: FLOODS
Walter Hays, Global Alliance for Disaster Reduction, Vienna,
Virginia, USA
Natural Phenomena that Cause Disasters
Planet Earth’s Atmospheric-lithospheric Interactions Cause:
Floods
NATURAL HAZARDS THAT HAVE CAUSED NATURAL HAZARDS THAT HAVE CAUSED DISASTERS IN NEW ZEALAND DISASTERS IN NEW ZEALAND
NATURAL HAZARDS THAT HAVE CAUSED NATURAL HAZARDS THAT HAVE CAUSED DISASTERS IN NEW ZEALAND DISASTERS IN NEW ZEALAND
FLOODS
WINDSTORMS
EARTHQUAKES
VOLCANOES
ENVIRONMENTAL CHANGE
GLOBAL CLIMATE CHANGE
HIGH BENEFIT/COST PROGRAMS FOR BECOMING DISASTER RESILIENT
HIGH BENEFIT/COST PROGRAMS FOR BECOMING DISASTER RESILIENT
GOAL: PROTECT PEOPLE GOAL: PROTECT PEOPLE AND COMMUNITIESAND COMMUNITIES
GOAL: PROTECT PEOPLE GOAL: PROTECT PEOPLE AND COMMUNITIESAND COMMUNITIES
ELEMENTS OF RISK AND DISASTER
HAZARDSHAZARDSHAZARDSHAZARDS
ELEMENTS OF FLOOD RISK ELEMENTS OF FLOOD RISK ELEMENTS OF FLOOD RISK ELEMENTS OF FLOOD RISK
EXPOSUREEXPOSUREEXPOSUREEXPOSURE
VULNERABILITYVULNERABILITYVULNERABILITYVULNERABILITY LOCATIONLOCATIONLOCATIONLOCATION
RISKRISKRISKRISK
RUGGED TOPOGRAPHY AND THE WAIMAKARIRI RIVER FLOODPLAIN
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.
FLOOD HAZARDS:
ARE POTENTIAL DISASTER AGENTS
FLOOD HAZARDS
• TOO MUCH WATER DISCHARGED WITHIN THE DRAINAGE SYSTEM TO BE ACCOMMODATED IN THE REGIONAL WATER CYCLE
• INUNDATION
• EROSION
• SCOUR
• MUDFLOWS
A DISASTER CAN HAPPENWHEN THE
POTENTIAL DISASTER AGENTS OF A FLOOD INTERACT WITH
THE VULNERABLE BUILT ENVIRONMENTS OF NEW
ZEALAND’S COMMUNITIES
A DISASTER CAN HAPPENWHEN THE
POTENTIAL DISASTER AGENTS OF A FLOOD INTERACT WITH
THE VULNERABLE BUILT ENVIRONMENTS OF NEW
ZEALAND’S COMMUNITIES
NEW ZEALAND’S CITIES
A DISASTER is ---
--- the set of failures that overwhelm the capability of a community to respond 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.
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.
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.
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.
THE REASONS ARE . . .
• The community has NO DISASTER PLANNING SCENARIO or WARNING SYSTEM in place as a strategic framework for concerted local, national, regional, and international countermeasures.
THE REASONS ARE . . .
• The community LACKS THE CAPACITY TO RESPOND in a timely manner to the full spectrum of expected and unexpected emergency situations.
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.
NOTABLE FLOOD DISASTERS
FEBRUARY 13, 2004
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.
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.
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.
FLOOD DISASTER OF 2004
• As a result of 2004’s flooding, vegetable prices increased more than 200 percent.
ECONOMIC LOSS:
ESTIMATED AT $200 million.
NOTABLE FLOOD DISASTERS
SOUTH ISLAND DECEMBER 13, 2011
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).
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.
DEC. 13 FLOODING
DEC. 13 FLOODING
DEC. 13 FLOODING
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.
DEC. 13 FLOODING
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.
NOTABLE FLOOD IMAGES
HIGH DISCHARGE AFTER A STORM
FLOODING: WHAKATANE RIVER
INUNDATION
CHRISTCHURCH: FLOODING
FLOODING: SOUTH ISLAND
CYCLONE BOLA PASSED NEAR NEW ZEALAND : MARCH 1988
FLOODING AFTER CYCLONE BOLA
FLOODING
FLOOD INDUCED LANDSLIDE
ROAD WASHED OUT
NEW ZEALAND’S NEXT FLOOD IS INEVITABLE
NEW ZEALAND’S NEXT FLOOD IS INEVITABLE
• ---SO, START IMPLEMENTING MEASURES FOR BECOMING MORE RESILIENT TO A FLOOD DISASTER NOW.
THE ALTERNATIVE TO A FLOOD DISASTER IS
FLOOD DISASTER RESILIENCE
THE ALTERNATIVE TO A FLOOD DISASTER IS
FLOOD DISASTER RESILIENCE
NEW NEW ZEALAND’S ZEALAND’S
COMMUNITIESCOMMUNITIES
NEW NEW ZEALAND’S ZEALAND’S
COMMUNITIESCOMMUNITIES
DATA BASES DATA BASES AND INFORMATIONAND INFORMATIONDATA BASES DATA BASES AND INFORMATIONAND INFORMATION
HAZARDS: GROUND SHAKING GROUND FAILURE SURFACE FAULTING TECTONIC DEFORMATION TSUNAMI RUN UP AFTERSHOCKS
• FLOOD HAZARDS•INVENTORY•VULNERABILITY•LOCATION
FLOOD RISK FLOOD RISK
RISK
ACCEPTABLE RISK
UNACCEPTABLE RISK
FLOOD DISASTER FLOOD DISASTER RESILIENCERESILIENCE
•PREPAREDNESS•PROTECTION•FORECASTS/SCENARIOS•EMERGENCY RESPONSE•RECOVERY and RECONSTRUCTION
POLICY OPTIONSPOLICY OPTIONS
LESSONS LEARNED ABOUT DISASTER RESILIENCE
ALL FLOODS PREPAREDNESS FOR ALL OF THE LIKELY FLOOD HAZARDS IS ESSENTIAL FOR DISASTER RESILIENCE
LESSONS LEARNED ABOUT DISASTER RESILIENCE
ALL FLOODS PROHIBITING THE CONSTRUCTION OF BUILDINGS AND LIFELINE SYSTEMS IN A RIVER FLOODPLAIN IS ESSENTIAL FOR DISASTER RESILIENCE
LESSONS LEARNED ABOUT DISASTER RESILIENCE
ALL FLOODS EARLY WARNING AND EVACUATION PLANS TO MOVE PEOPLE TO SAFE HAVENS ARE ESSENTIAL FOR DISASTER RESILIENCE
LESSONS LEARNED ABOUT DISASTER RESILIENCE
ALL FLOODS EFFICIENT AND TIMELY EMERGENCY RESPONSE IS ESSENTIAL FOR DISASTER RESILIENCE
LESSONS LEARNED ABOUT DISASTER RESILIENCE
ALL FLOODS TIMELY RECONSTRUCTION AND RESTORATION OF SERVICES TO NORMAL IS ESSENTIAL FOR RECOVERY AND DISASTER RESILIENCE