Ch 13 Natural_Hazard Mitigation

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Natural Hazards Weather-related hazards and disasters

Hurricanes, coastal storms

Flooding, blizzards, tornados

Extreme heat, cold, drought

Geologic hazards and disasters

Earthquakes, tsunamis, volcanic eruptions

Slope hazards: landslides, avalanches

Support hazards: sinkholes, subsidence,

liquefaction

Wildfire hazards



We’ve seen our share in the last decade, the

last year, the last month, the last week… This year:

Northeast flooding from Hurricane Irene, South/Mid-Atlantic flooding from TS Lee

Texas drought and wildfires

Midwest spring flooding; Killer tornadoes, Joplin, Midwest

Japanese earthquake, tsunami Massive winter blizzards in U.S.; Record January floods in Australia, Brazil

Last 2 years: 2010 Haitian earthquake (316,000 dead); major earthquakes in Chile, Turkey, New Zealand

(2010, 2011), China (2009)

2010 Pakistan floods: 1600 dead, 6 million displaced; 2010 Russian drought, heat wave,wildfires

2010 Tennessee floods, 2009 Atlanta flood; 2009 California wildfires

Last decade: 2004 Sumatran tsunami (230,000 dead among the top ten deadliest natural disasters of all time

2005 Katrina, 2008 Ike, 2004 Florida hurricanes among most damaging hurricanes in U.S. 2003 Extreme heat in Europe kills 40,000












http://slidepdf.com/reader/full/ch-13-naturalhazard-mitigation 8/100Midwest floods May, June 2011



Nebraska nuclear power plants threatened by floods



2011: most deadly tornado season in U.S.

Joplin, Missouri, Tornado



Japanese earthquake and tsunami





Chicago snow in February



Connecticut snow in January



2011 Australia Flooding





2011 Brazil Floods and Landslides





2010 Haitian Earthquake



2004 Tsunami, Banda Aceh, Sumatra, Indonesia



California wildfires 2009





2009 China Earthquake



Extreme Weather: Florida 2004 The vast majority of that destruction has been inflicted on Florida, whose

miseries began August 13, when Hurricane Charley slammed intoPunta Gorda—about 70 miles (113 kilometers) south of Tampa— with winds of 145 miles an hour. Charley's wind speeds made it a Category 4.

Hurricane Frances, a Category 2 hurricane, came next, striking on

Labor Day weekend.

Then came Hurricane Ivan, at one point, one of the most fearsomestorms on record. Ivan had winds of 165 miles an hour as it rolled acrossthe Caribbean. Ivan lost strength before making landfall near Mobile, Alabama, but the hurricane's front right quadrant— which always packs

the most powerful punch—

slammed into Pensacola, Florida. Finally, Hurricane Jeanne was the 4th .

Florida damages:

Charley: $7B Frances: $6B Ivan: $35B Jeanne: $8B Total: $56B

Loss of life: 100 dead



Punta Gordo

In path of

Hurricane

Charley







Main Street, Salem,

September 28, 2004



Reserve Avenue, Roanoke,

September 28, 2004

2005 H i K t i > 1800 d d



2005: Hurricane Katrina-> 1800 dead

K t i ’ d t Bil i Mi i i i



Katrina’s damage to Biloxi, Mississippi

















What Went Wrong with Katrina?(Wall Street Journal (9/6/05)

Some reasons why the U.S. didn’t adequately protect andrescue its citizens from a natural disaster

The absorption of the Federal Emergency Management Agencyinto the gargantuan--and terror-focused — Department of

Homeland Security A military stretched by wars in Iraq and Afghanistan, which made

commanders reluctant to commit some active duty units nearby

A total breakdown in communications systems

Missteps at the local level, including a rudimentary plan to dealwith hurricanes

A failure to plan for the possibility that New Orleans’ leveesystem would fail.



What should we have done?

What should we do next time? Contingency Planning?

Emergency Response?

Mobilization?

Land Use Planning?

Education?

Reconstruction?

Natural Hazard Mitigation Planning?

N t l H d /Di t



What type of problem is this?

• Ethical?• Social?• Population?• Economic?• Political?• Technical?• Legal?• Regulatory?• Planning?

Natural Hazards/Disasters

Natural Hazard/Disaster Mitigation



Natural Hazard/Disaster Mitigation

Natural Hazard Mitigation Planning

Flooding Hazard Mitigation Structural measures

Flood Plain Management

Hurricanes and Coastal Flooding

Structural measures

Smart coastal development practices

Geologic Hazard Mitigation

Support Problems: Karst, Sudsidence, Stability

Slope Problems: Stability, Landslides, Avalanches

Seismic Problems: Earthquakes, Tsunamis, Volcanoes Wildfire



Hazard, Exposure, Vulnerability, and Risk

Hazard is the inherent danger associated with a potentialproblem, such as an earthquake or avalanche.

Exposure is the human population, ecological resource, orproperty exposed to the hazard.

Vulnerability is the unprotected nature of the exposure.Vulnerability can be reduced by engineering design (e.g.,flood-proofing, earthquake resistant design).

Risk is the probable degree of injury and damage likely to

occur from exposure of people and property to the hazardover a specific time period. Risk analysis involves combining(or overlaying as maps) assessment of relative hazard,exposure, and vulnerability, as well as analyzing theprobability of occurrence.





Do we rebuild, how do we rebuild New Orleans?



Hierarchy of

Environmental Impact Mitigation Strategies Emergency Response (contingency planning for

emergency disaster response)

Avoid the impact (move away altogether)

Lessen the impact by modifying location on site (move away to lesser impact area)

Lessen the impact by modifying design (applyengineering or design features)

Offset the impact (compensate for the impact by

monetary relief, reconstruction, or re-creation)

Disaster Response Planning



Disaster Response Planning We won’t be able to prevent or mitigate all natural hazards

Contingency Planning:“What do we do if..” planning Worst Case Scenarios:

think the unthinkable because it might happen

assess the probability and risk

Emergency Preparedness: education

predictive models

warning systems

monitoring

resources for response: $$, supplies, manpower

Emergency Response: communication

mobilization

Are some disasters so great we cannot anticipate them?



Natural Hazard Mitigation Planning

Identify Objectives Assess situation: Hazard and risk

assessment

Develop mitigation alternatives: Assess options and formulate

Natural Hazard Mitigation Plan:

Implement the Natural HazardMitigation Plan Evaluate the Mitigation Plan during

and after each natural hazard event



FloodingNearBuena Vista,Virginia,June 1995

Vi t St di R k



Victory Stadium, Roanoke,

September 28, 2004



Approaches to Flood Hazard Mitigation



Approaches to Flood Hazard Mitigation Structural Measures:

Guide flood waters by building levees, flood walls, channel enlargement

(flood protection); Lessen flood waters (peak discharge) through upland runoff control

measures including detention (dams and reservoirs) (flood abatement);

Adjust site characteristics by elevating sites with fill material;

Adjust building characteristics by elevating and floodproofing structuresand related infrastructure.

Non-structural Measures: Do nothing;

Provide emergency preparedness measures such as flood warnings;

Provide emergency response

Provide relief, through private and federal disaster assistance; Provide affordable insurance for flood damages;

Provide information, such as maps of flood plains and general informationabout flood risks and safe flood plain building practices;

Adjust future land use by flood plain planning, vacant land acquisition,and regulatory zoning;

Adjust existing land use by acquiring and relocating buildings.





The floodway is a fairly narrow area close to the stream that must remain



The ood ay is a fairly narrow area close to the stream that must remain

open so that flood waters can pass through. The floodway fringe is the area within the 1% (100-yr) flood plain that canbe subject to encroachment or filling without causing more than a one-foot

surcharge in the height of the 1% (100-yr) flood carried by the floodway.

FloodwayFloodway

Fringe

Floodway

Fringe



FEMA rules for floodplain development under

the National Flood Insurance Program: http://www.fema.gov/business/nfip/fhamr.shtm

The regulatory floodway, which is adopted into the community's floodplain management

ordinance, is the stream channel plus that portion of the overbanks that must be kept free

from encroachment in order to discharge the 1-percent-annual-chance flood without

increasing flood levels by more than 1.0 foot

The intention of the floodway is not to preclude development. Rather, it is intended to assist

communities in prudently and soundly managing floodplain development and prevent additional

damages to other property owners.

The community is responsible for prohibiting encroachments, including fill, new

construction, and substantial improvements, within the floodway unless it has been

demonstrated through hydrologic and hydraulic analyses that the proposed encroachment will not

increase flood levels within the community. In areas that fall within the 1-percent-annual-chance floodplain, but are outside the floodway

(termed the "floodway fringe"), development will, by definition, cause no more than a 1.0-

foot increase in the 1-percent-annual-chance water-surface elevation.

Floodplain management through the use of the floodway concept is effective because it allows

communities to develop in floodprone areas if they so choose, but limits the future increases of

flood hazards to no more than 1.0 foot.

http://www.fema.gov/business/nfip/fhamr.shtm





Flood Plain Zoning using a Floodway Fringe District



Code of Blacksburg http://www.municode.com/resources/gateway.asp?pid=10159&sid=46

Section 3248 and 3231-32, 3234:

In the Floodway, Flood Fringe, and Approximated Floodplain, no

development shall be permitted except where the effect of suchdevelopment on flood heights is fully offset by accompanying improvements

which have been approved by all appropriate authorities as required above.

Creek Overlay District for Tom’s and Stroubles Creeks and Slate Branch:

1) All areas of 25% or greater slopes adjacent to the flood plain, or if no flood

plain is present, 25% or greater slopes that begin within 50 feet of the creek

channel;2) All wetlands contiguous to lands described above;

3) All the land within a corridor defined by a boundary line which is 50 feet from

the center line of the creek, provided this land is not included in the Creek

Valley Overlay as a result of 1 or 2 above.

Flood Hazard Boundary Map

http://www.municode.com/resources/gateway.asp?pid=10159&sid=46





Flood Hazard Boundary Map



Flood Insurance Rate Map



Limits of FEMA-guided

Flood Plain Management Controls new development only

Limits restrictions in Floodway only

False sense of security for Floodway

Fringe and elevations >100 year flood level

Actually encourages development in

sensitive riparian zone in Floodway Fringe

Coastal Hazards





Number of Category 3 or higherHurricanes by County, 1980-2005



Hurricane Andrew in Florida





Coastal Flood Zones













Conventional and Alternative Shoreline

Lot Layouts



Geologic Hazards Slope Stability

Falls, Slides, Slumps, FlowsLandslides

Inherant and Superimposed Factors

Support Problems

Settlement

Subsidence

Karst Seismic Problems

Earthquakes

Volcanic eruptions



Relative Landslide Risk in U.S.

2005 La Conchita Landslide, Ventura County, CA, killed 10





Mapping Slope Stability

Three factors:

% Slope = 100 x V/H (from slope analysis)

Landslide Inventory shows presence of Landslide Deposits (from aerial photos)

Underlying geology shows unconsolidated,

weak, or fractured materials (from geologic map)



Relative Slope Stability1. Stable: Areas of 0-5% slope that are not underlain by landslide

deposits.

2. Generally Stable: Areas of 5-15% slope that are not underlainby landslide deposits.

3. Generally Stable To Marginally Stable: Areas of greater than15% slope that are not underlain by landslide deposits orbedrock units susceptible to landsliding.

4. Moderately Unstable: Areas of greater than 15% slope that areunderlain by bedrock units susceptible to landsliding but not

underlain by landslide deposits. 5. Unstable: Areas of any slope that are underlain by or

immediately adjacent to landslide deposits.



Landslide Hazard Map, Seattle



Support Problems

Settlement: weak soils

Subsidence: removal of support material

Fluids: groundwater, crude oil, natural gas

Mined materials: coal, other minerals

Karst: solution carbonate rock geology

Sinkholes

Avenues for groundwater contamination



Areas of Karst Terrain



Karst, Sinkholes, and Groundwater



Sinkhole Collapse Risk Map



p p



Earthquake Hazards



Earthquake Hazards

Fault displacement

Ground shaking: extends far beyond the epicenter;

depends on underlying materials: e.g., hard rock has

less shaking than clay muds

Ground failure: e.g., landslides, liquefaction

Indirect hazards: e.g., ruptured lines, fire

Critical facilities: e.g., stadiums, hazardous

facilities, power plants



Effect of underlying geology:

1989 SF Bay Area earthquake



Mapping Earthquake Hazard

California’s Increasingly Stringent



g y g

Seismic Building Codes

The Safe Growth Audit



The Safe Growth Audita natural hazard assessment tool for local governments

COMPREHENSIVE PLAN

Land Use

Does the future land-use map clearly identify natural-hazard areas?

Do the land-use policies discourage development/redevelopment within hazard areas?

Does the plan provide space for future growth in areas outside of natural-hazard areas?

Transportation

Environmental Management

Public Safety

ZONING ORDINANCE

SUBDIVISION REGULATIONS

INFRASTRUCTURE POLICIES AND CAPITAL IMPROVEMENT

PROGRAM (CIP)



Limitations of Building CodesNelson and French, 2002

Reduce vulnerability to hazard up to a certain

magnitude; disasters exceeding this magnitude

can be catastrophic

False sense of security resulting in more

development, increasing exposure and risk

Increased development in related hazard lands(e.g.slopes) increasing risk of collateral damage



Limitations of Comprehensive Plans Often lack adequate factual information

Often lack strong policies based on facts

Often are less restrictive than should bebecause of fear of losing fiscal benefits of growth and development

Federal policies for disaster relief and aidfor reconstruction bale out communitieswith weak plans



More Effective Hazard Mitigation

Retrofitting older homes to current standards

Comprehensive plans can be effective atmitigating hazards if they contain high qualityelements (factual info, goals, policies, publicawareness) and effective implementation

Consistently effective quality andimplementation depends on local planning inconjunction with state/regional/federal mandatesand enforcement



Planning Mandates

Without state/regional mandates, localgovernments are usually ineffective inpreserving natural resources, containingsprawl, improving infrastructure delivery, andmitigating natural hazards

Planning mandates stimulate land analysis

Implementation of mandates variesconsiderably and depends on state/regional

oversight and enforcement

Wildfire Hazard



Wildfire Hazard









Evolution of Fire Management:



vo ut o o e a age e t:Moving from Suppression (“Put it Out!”) to

Ecological Restoration (“Let it burn.”) Dominant culture is suppression and militaristic approach to

combating fire at all costs (even the death of fire fighters)

Disturbance ecology indicates that fire is part of the natural system

and that by suppressing fire we create conditions for moredevastating fires

“Fire Learning Networks” across the U.S. sponsored by the Forest

Service and The Nature Conservancy are trying to change the

culture of fire management to prescribed burning, selective controlof wildfires, land use management to keep development out of

harm’s way, and letting most fires burn.

Live with nature, respect it, be smart, because we cannot control it.



Schwab’s Lessons for Hazard Mitigation Planning

Act before a disaster.

Foster patience, monitoring, and continuing evaluation.

Be strategic and opportunistic.

Nurture champions within planning staffs, elected officials, and the community

Develop the political necessary for implementation. Account for stakeholder values in light of hazard mitigation.

Emphasize multiple-objective planning to integrate hazard mitigation with other

community sustainability goals

Evaluate opportunities in the comprehensive plan for density reallocation.

Emulate the green building trend, fostering a safe building trend.

Communicate and educate risks and hazards.

Quantify mitigation benefits in economic, environmental and social metrics.

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Ch 13 Natural_Hazard Mitigation

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