Protecting Critical Facilities from Flood Risk Tennessee Association of Floodplain Management July...

Protecting Critical Facilities from Flood Risk

Tennessee Association of Floodplain Management

July 27, 2011

Roy McClure

DHS/FEMA Region IV

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This control panel was inundated with 3 feet of floodwater (yellow arrow). Sensitive electronic equipment was damaged (Columbus Junction, IA).

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This emergency generator—elevated 2 feet above the floor on a concrete base—was not directly affected by floodwaters, but was rendered ineffective because the transfer switch was mounted below the transformer and flooded during the event (Cedar Rapids, Iowa).

What is a Critical Facility?

A facility that is essential for community’s vitality.

Critical Systems

Electrical systems (including power, life-safety, communication, and IT equipment)

Plumbing systems (including water, sanitary, and mechanical piping)

Heating, ventilating, and air conditioning (HVAC) systems

Specialized equipment (including conveyance, medical, and detention equipment)

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What is a Critical Facility?

Man-made structures and improvements:1. Have potential to cause serious bodily

harm2. Have potential to cause extensive

property damage3. If damaged, would cause disruption of

vital services

What is a Critical Facility?

Essential Governmental Facilities

Essential facilities

Transportation systems

Lifeline utility systems

High Potential Loss Facilities

Hazardous Materials Storage Facilities

What is a Critical Facility?

Impacts of even the smallest chance of flooding too great?

If flooded, would add another dimension to the flood?

Could the facility be evacuated without loss of life?

Would essential records/services be lost?

Would services by facility be disrupted? Police, Fire, EOC, Hospitals Data centers, Schools, Water Treatment Plants Sewer Treatment Plants

Governing Regulations

Executive Order 11988

Flood Damage Prevention Ordinances

State/Local Building Codes

Coastal Zone Management Regulations

Erosion and Sediment Control

Special Purpose Ordinances

Factors affecting Flood Damage

Channel/floodplain obstructions

Erosion/Sedimentation

Increased upland development

Subsidence

Wave/Debris impacts

Failure of levees

Failure of dams

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Flood Loads

Hydrostatic loads Buoyancy

Hydrodynamic loads

Breaking wave loads

Debris impact loads

Long-term erosion and local scour

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Vulnerability to Flood Damage

Site Damage Erosion/scour

Debris/sediment removal

Landscaping

Fences

Accessory structures

Access roads

Parking lots/garage

Drainage facilities

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Collapsed fence

Road damage

Vulnerability to Flood Damage

Structural Damage

Load-bearing walls

Floors

Collapse

Nonstructural Damage

Mold above flood level

Cabinets/finishes

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Ruptured floor Cracked wall

Collapse by scour

Vulnerability to Flood Damage

Utility System Damage

Displacement of equipment

Elevators

Corrosion

Generators

Tanks

Water/sewer

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Generator elevated, but failed to operate due to submergence

Vulnerability to Flood Damage

Contents Damage

Furniture

Computers

Appliances

Records

Kitchen goods

Vehicles

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Medical records saturated by floodwaters

Kitchen appliances and equipment displaced

Risk Reduction in A-Zones

Site Modifications

Earthen fill

Excavation

Earthen levee

Floodwall

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Floodwall

Levee

Risk Reduction in A-ZonesElevation Considerations

Slab-on-grade on fill

Stem wall foundation

Column foundation

Crawlspace

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Municipal building on fill

Stem wall foundation

Column foundation

Lowest Floor ≥ (0.2% (500-year) flood elevation + FB)

Risk Reduction in A-Zones

Floodproofing Considerations

Limit for flood velocities ≤ 5 fps Warning time ≥ 12 hours (w/o a warning system) At least 1 exit door for escape above the DFE

Approved emergency plan, posted in 2 locations Location of panels and hardware Entity and methods of installation Schedule for maintenance Schedule for periodic practices and drills

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ASCE-24

Intended to reduce only physical damage

Risk Reduction in V-ZonesConsiderations

Bottom of lowest horizontal structural member of the Lowest Floor ≥ (0.2% (500-year) flood elevation + FB)

Elevated on pilings or columns Free-of-obstruction below the Lowest Floor

Breakaway walls an option below Lowest Floor

Corrosion-resistant connections

Use below LF (parking, storage, building access)

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Risk Reduction in V-Zones Higher foundations than the DFE Scour and erosion Flood-borne debris

Continuous load path (corrosion-resistant connections)

Emergency equipment well above the DFE

Use lowest elevated floor to non-critical uses not to impair critical functioning during post-flood recovery

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Risk Reduction in Coastal A-Zones

Breaking waves from 1.5 to 3 feet high; landward of V-Zone or open coast with no V-Zone

Significantly more damage potential

ASCE-24 requires V-Zone standards Floodproofing may be less feasible alternative

Corrosion-resistant connections

Use limitations below LF (parking, storage, and building access)

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Risk Reduction in A- and V-Zones

Material Considerations

Flood resistant (extended contact) Non-coastal: 72 hours Coastal: 12 hours

USACE Classes acceptable Class 5 Class 4

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Ref.: NFIP Technical Bulletin 2

Risk Reduction for Related facilities

Access roads Safety factors Floodplain and environmental impacts Drainage structures and surface design

Utility installations

Potable water and wastewater systems

Storage tank installations

Accessory structures

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Equipment room with water-tight door

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OVERALL

Reducing Flood Losses

Locate outside the 0.2 % (500-year) floodplain

Elevation At least to 0.2% flood elevation

Floodproofing At least to 0.2% flood elevation Effective for only up to 3 to 4 feet of floodwater Good for protection of equipment

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In all cases, maintain dry land ingress and egress for ordinary and emergency vehicles above the 0.2% flood elevation.

Hazard Mitigation Measures

Incorporate at all stages and levels of:

Planning

Design Maintenance Reconstruction Rehabilitation

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Elevated utility box

Resources1. National Flood Insurance Program Home page

www.fema.gov/business/nfip FEMA 543 – Design Guide for Improving Critical Facility

Safety from Flooding and High Winds, January 2007 Technical Bulletins

2. Association of State Floodplain Managers, Inc. www.floods.org Critical Facilities and Flood Risk

3. Executive Order 11988

4. Water Resources Council -- Floodplain Management Guidelines for Implementing EO 11988, February 10, 1978

Insurance

Flood

Hazard

Flood

Hazard

NFIP

Risk Reduction

PPRoy McClureroy.mcclure@dhs.gov770-220-8835

Susan Wilsonsusan.wilson@dhs.gov770-220-5414

Questions?