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Protecting Critical Facilities from Flood Risk Tennessee Association of Floodplain Management July 27, 2011 Roy McClure DHS/FEMA Region IV
This control panel was inundated with 3 feet of floodwater (yellow arrow). Sensitive electronic equipment was damaged (Columbus Junction, IA).
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)
What is a Critical Facility? • Man-made structures and improvements: • Have potential to cause serious bodily harm • Have potential to cause extensive property damage • 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
Flood Loads • Hydrostatic loads • Buoyancy • Hydrodynamic loads • Breaking wave loads • Debris impact loads • Long-term erosion and local scour
Vulnerability to Flood Damage • Site Damage • Erosion/scour • Debris/sediment removal • Landscaping • Fences • Accessory structures • Access roads • Parking lots/garage • Drainage facilities Collapsed fence Road damage
Vulnerability to Flood Damage • Structural Damage • Load-bearing walls • Floors • Collapse • Nonstructural Damage • Mold above flood level • Cabinets/finishes Ruptured floor Cracked wall Collapse by scour
Vulnerability to Flood Damage • Utility System Damage • Displacement of equipment • Elevators • Corrosion • Generators • Tanks • Water/sewer Generator elevated, but failed to operate due to submergence
Vulnerability to Flood Damage • Contents Damage • Furniture • Computers • Appliances • Records • Kitchen goods • Vehicles Kitchen appliances and equipment displaced Medical records saturated by floodwaters
Risk Reduction in A-Zones • Site Modifications • Earthen fill • Excavation • Earthen levee • Floodwall Levee Floodwall
Risk Reduction in A-Zones • Elevation Considerations • Slab-on-grade on fill • Stem wall foundation • Column foundation • Crawlspace Municipal building on fill Stem wall foundation Lowest Floor ≥ (0.2% (500-year) flood elevation + FB) Column foundation
Risk Reduction in A-Zones Intended to reduce only physical damage • 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 ASCE-24
Risk Reduction in V-Zones • Considerations • 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)
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
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)
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 • 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 Equipment room with water-tight door
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 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 Elevated utility box
Resources • 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 • Executive Order 11988 • Water Resources Council -- Floodplain Management Guidelines for Implementing EO 11988, February 10, 1978
Roy McClureroy.email@example.comSusan Wilsonsusan.firstname.lastname@example.org Risk Reduction Questions? NFIP P Insurance Flood Hazard