protecting critical facilities from flood risk tennessee association of floodplain management july...
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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 [email protected]
Susan [email protected]
Questions?