A-Zones A-Zones are found on all Flood Hazard Boundary Maps
(FHBMs), Flood Insurance Rate Maps (FIRMs), and Flood Boundary and Floodway Maps (FBFMs). An A-Zone is an area that would be flooded by the Base Flood, and is the same as a Special Flood Hazard Area (SFHA) or a 100-year floodplain. These areas may be unnumbered as AE, AH, or AO Zones. Numbered A-Zones indicates an area’s risk to flooding.
Acquisition Local governments can acquire lands in high hazard areas through conservation easements, purchase of development rights, or outright purchase of property.
Asset Any
manmade or natural feature that has value, including, but not limited to
people; buildings; infrastructure like bridges, roads, and sewer and water
systems; lifelines like electricity and communication resources; or
environmental, cultural, or recreational features like parks, dunes, wetlands,
or landmarks
Base Flood A term used in the National Flood Insurance Program to indicate the minimum size a flood to be used by a community as a basis for its floodplain management regulations; currently required by regulation to be that flood which has a one-percent chance of being equal or exceeded in any given year. Also known as a 100-year flood elevation or 0ne-percent chance flood.
Base Flood Elevation The elevation for which there is a one-percent chance in any (BFE) given year that flood levels will equal or exceed it. The BFE is determined by statistical analysis for each local area and designated on the Flood Insurance Rate Maps. It is also known as 100-year flood elevation.
Base Floodplain The floodplain that would be inundated by a one-percent chance (100-year) flood.
Building A structure that is walled and roofed, principally above ground and permanently affixed to a site. The term includes a manufactured home on a permanent foundation on which the wheels and axles carry no weight.
Building Code The regulations adopted by a local governing body setting forth standards for the construction, addition, modification, and repair of buildings and other structures for the purpose of protecting the health, safety, and general welfare of the public.
Community Community means any State or area or political subdivision thereof, or any Indian tribe or authorized tribal organization, or Alaska Native village or authorized native organization, which has the authority to adopt and enforce floodplain management regulations for the areas within its jurisdiction.
Community Rating System The Community Rating System is a voluntary program
(CRS) that each municipality or county government can choose to participate in. The activities that are undertaken through CRS are awarded points. A community’s points can earn people in their community a discount on their flood insurance premiums.
Critical Facility Facilities that are critical to the health and welfare of the population and that are especially important following hazard events. Critical facilities include, but are not limited to shelters, police and fire stations, and hospitals.
Designated Floodway The channel of a stream and that portion of the adjoining floodplain designated by a regulatory agency to be kept free of further development to provide for unobstructed passage of flood flows.
Development Development means any man-made change to improved or unimproved real estate, including but not limited to buildings or other structures, mining, dredging, filling, grading, paving, excavation or drilling operations or of equipment or materials.
Digitize To convert electronically points, lines, and area boundaries shown on maps into x, y coordinates (e.g., latitude and longitude, universal transverse mercator (UTM), or table coordinates) for use in computer application.
Disaster Mitigation Act DMA 2000 (public Law 106-390) is the latest legislation
Of 2000 (DMA 2000) to improve the planning process. It was signed into law on October 10, 2000. This new legislation reinforces the importance of mitigation planning and emphasizes planning for disasters before they occur.
Earthquake A sudden motion or trembling that is caused by a release of strain accumulated within or along the edge of earth’s tectonic plates.
Elevation The placement of a structure above flood level to minimize or prevent flood damages.
Erosion Wearing away of the land surface by detachment and movement of soil and rock fragments, during a flood or storm or over a period of years, through the action of wind, water, or other geologic processes.
Federal Emergency Independent agency created in 1978 to provide a single
Management Agency point of accountability for all federal activities related to
(FEMA) disaster mitigation and emergency preparedness, response and recovery.
Flash Flood A flood that crests in a short length of time and is often characterized by high velocity flow. It is often the result of heavy rainfall in a localized area.
Flood Elevation Elevation of the water surface above an establish datum, e.g. National Geodetic Vertical Datum of 1929, North American Datum of 1988, or Mean Sea Level.
Flood or Flooding Flood or Flooding means a general and temporary condition of partial or complete inundation of normally dry land areas from: (1) the overflow of inland or tidal waters. (2) The unusual and rapid accumulation or runoff of surface waters from any source. (3) Mudslides (i.e., mudflows) which are proximately caused by flooding. The collapse or subsidence of land along the shore of a lake or other body of water, accompanied by a severe storm, or by an unanticipated force of nature, such as flash flood or an abnormal tidal surge, or by some similarly unusual and unforeseeable event, may also be defined as flooding.
Flood Control Keeping flood waters away from specific developments or populated areas by the construction of flood storage reservoirs, channel alterations, dikes and levees, bypass channels, or other engineering works.
Flood Disaster Assistance Flood disaster assistance includes development of comprehensive preparedness and recovery plans, program capabilities, and organization of Federal agencies and of State and local governments to mitigate the adverse effects of disastrous floods. It may included maximum hazard reduction, avoidance, and mitigation measures, as well policies, procedures, and eligibility criteria for Federal grant or loan assistance to State and local governments, private organizations, or individuals as the result of the major disaster.
Flood Fringe That portion of the floodplain that lies beyond the floodway and serves as a temporary storage area for floodwaters during a flood. This section receives waters that are shallower and of lower velocities than those of the floodway.
Flood Hazard Flood Hazard is the potential for inundation and involves the risk of life, health, property, and natural value. Two reference base are commonly used: (1) For most situations, the base flood is that flood which has a one-percent chance of being exceeded in any given year (also known as the 100-year flood); (2) for critical actions, an activity for which a one-percent chance of flooding would be too great, at a minimum the base flood is that flood which has a 0.2 percent chance of being exceeded in any given year (also known as the 500-year flood).
Flood hazard Boundary Map Flood Hazard Boundary Map (FHBM) means an official
(FHBM) map of a community, issued by the Administrator, where the boundaries of the flood, mudslides (i.e., mudflow) related erosion areas having special hazards have been designated as Zones A, M, and/or E.
Flood Insurance Rate Map Flood Insurance Rate Map (FIRM) means an official map of a community, on which the Administrator has delineated both the special hazard areas and the risk premium zones applicable to the community.
Flood Insurance Study Flood Insurance Study or Flood elevation study means an examination, evaluation and determination of flood hazards and, if appropriate, corresponding water surface elevations, or an examination, evaluations and determination of mudslide (i.e., mudflow) and/or flood-related’ erosion hazards.
Floodplain Floodplain or flood-prone area means any land area susceptible to being inundated by water from any source (see definition of flooding).
Floodplain Management The operation of an overall program of corrective and preventive measures for reducing flood damage, including but not limited to emergency preparedness plans, flood control works and floodplain management regulations.
Floodplain Management Floodplain Management Regulations means
Regulations zoning ordinances, subdivision regulations, building codes, health regulations, special purpose ordinances (such as floodplain ordinance, grading ordinance and erosion control ordinance) and other applications of police power. The term describes such state or local regulations, in any combination thereof, which provide standards for the purpose of flood damage prevention and reduction.
Floodproofing Any combination of structural and nonstructural additions, changes, or adjustments to structures which reduce or eliminate flood damage to real estate or improved property, water and sanitary facilities, structures and their contents.
Floodway Floodway means the channel of a river or other watercourse and the adjacent land areas that must be reserved in order to discharge the base flood without cumulatively increasing the water surface elevation more than a designated height.
Flood Zones Zones on the Flood Insurance Rate Map (FIRM) in which a Flood Insurance Study has established the risk premium insurance rates.
Zone Symbol A Area of special flood hazard without water
surface elevations determined.
A1-30, AE Area of special flood hazard with water surface elevations determined.
AO Area of special flood hazard having shallow water depths and/or unpredictable flow paths between one and three feet.
A-99 Area of special flood hazard where enough progress has been made on a protective
system, such as dikes, dams, and levees, to
consider it complete for insurance rating
purposes.
water depths and/or unpredictable flow
paths between one and three feet and with
water surface elevations determined.
B, X Area of moderate flood hazard.
C, X Area of minimal hazard.
D Area of undetermined but possible flood
hazard.
Freeboard Freeboard means a factor of safety usually expressed in feet above a flood level for purposes of floodplain management. Freeboard tends to compensate for many unknown factors that could contribute to flood heights greater than the height calculated for a selected size flood and floodway conditions, such as wave action, bridge openings, and the hydrological effect of urbanization of the watershed.
Fujita Scale of Tornado Rate tornadoes with numeric value from F0 to F5 based
Intensity on tornado wind speed and damage sustained. An F0 indicates minimal damage such as broken tree limbs or signs, while F5 indicates severe damage sustained.
Geographical Information A computer software application that relates physical
System (GIS) features on the earth to a database to be used for mapping and analysis.
Hazard A source of potential danger or adverse condition. Hazards in the context of this plan will include naturally occurring events such as floods, earthquakes, tornadoes, tsunami, coastal storms, landslides, and wildfires that strike populated areas. A natural event is a hazard when it has the potential to harm people or property.
Hazard Event A specific occurrence of a particular type of hazard.
Hazard Identification The process of identifying hazards that threaten an area.
Hazard Mitigation Sustained action taken to reduce or eliminate long-term risk from hazards and their effects.
Hazard Profile A description of the physical characteristics of hazards and a determination of various descriptors including magnitude, duration, frequency, probability, and extent. In most cases, a community can most easily use these descriptors when they are recorded and displayed as maps.
Hydrology The science of the behavior of water in the atmosphere, on the earth’s surface, and underground.
Infrastructure Refers to the public service of a community that have a direct impact on the quality of life. Infrastructure includes communication technology such as phone lines or Inernet access, vital services such as public water supplies and sewer treatment facilities, and includes an area’s transportation system such as airports, heliports; highways, bridges, tunnels, roadbeds, overpasses, railways, bridges, rail yards, depots; and waterways, canals, locks, seaports, ferries, harbors, dry-docks, piers and regional dams.
Intensity A measure of the effects of a hazard event at a particular place.
Landslide Downward movement of slope and materials under the force of gravity.
Liquefaction The phenomenon that occurs when ground shaking causes loose soils to lose strength and act like viscous fluid. Liquefaction causes two types of ground failure: lateral spread and loss of bearing strength.
Local Emergency LEPCs consist of community representatives and are
Planning Committee (LEPC) appointed by the State Emergency Response Commissions (SERCs), as required by Superfund Amendments and Reauthorization Act (SARA), Title III. They develop an emergency plan to prepare for and respond to chemical emergency. They are also responsible for coordinating with local facilities to find out what they are doing to reduce hazards, prepare for accidents, and reduce hazardous inventories and releases. The LEPC serves as a focal point in the community for information and discussion about hazardous substances, emergency planning, and health and environmental risks.
Magnitude A measure of the strength of a hazard event. The magnitude (also referred to as severity) of a given hazard event is usually determined using technical measures specific to the hazard.
Mitigate To cause something to became less harsh or hostile, to make less severe or painful.
Mitigation Plan A systematic evaluation of the nature and extent of vulnerability to the effects of natural hazards typically present in the state and includes a description of actions to minimize future vulnerability to hazards.
National Flood Insurance The Federal program, created by an act of Congress in
Program (NFIP) 1968 that makes flood insurance available in communities that enact satisfactory floodplain management regulations.
National weather Service Prepares and issues flood, severe weather, and coastal
(NWS) storm warnings and can provide technical assistance to federal and state entities in preparing weather and flood warning plans.
New Construction New construction means structures for which the “start of construction” on or after the effective date of a floodplain management regulation adopted by a community and includes any subsequent improvement to such structures.
Nonstructural Floodplain Those measures, such as flood proofing, employed to
Management Measures modify the exposure of buildings to floods and use planning, warning, schemes, and insurance as opposed to structural measures (such as dams, levees, and channel modifications).
Nor’easter An extra-tropical cyclone producing gale-force winds and precipitation in the form of heavy snow and rain.
One Hundred (100)-Year The flood elevation that has a one-percent chance of
Flood being equaled or exceeded in any given year. It is also known as the base flood.
Permeability The property of soil or rock that allows water to pass through it.
Planning The act or process of making or carrying out plans; the establishment of goals, policies and procedures for social or economic unit.
Preparedness Actions that strengthen the capabilities of government, citizens, and communities to respond to disasters.
Probability A statistical measure of the likelihood that a hazard event will occur.
Recovery The actions taken by an individual or community after a catastrophic event to restore order and lifelines in a community.
Regulatory Floodplain That portion of the floodplain subject to floodplain regulations (usually the floodplain inundated by one-percent chance flood).
Regulatory Floodway Regulatory Floodway means the channel of a river or other watercourse and the adjacent land areas that must be reserved in order to discharge the base flood without cumulatively increasing the water surface elevation more than a designated height.
Regulatory Power Local jurisdictions have the authority to regulate certain activities in their jurisdiction. With respect to mitigation planning, the focus is on such things as regulating land use development and construction through zoning, subdivision regulations, design standards, and floodplain regulations.
Relocation The moving of a structure from a flood area to a new location, normally to one where there is no threat of flooding.
Repetitive Loss Property A property that is currently insured for which two or more National Flood Insurance Program losses (occurring more than ten days apart) of at least $1000 each have been paid within any 10-year period since 1978.
Response The actions taken during an event to address immediate life and safety needs and minimize further damage to properties.
Richer Scale A numerical scale of earthquake magnitude devised by seismologist C.F. Richter in 1935.
Risk The estimated impact that a hazard would have on people, services, facilities, and structures in a community; the likelihood of a hazard event resulting in an adverse condition that causes injury or damage. Risk is often expressed in relative terms such as a high, moderate or low likelihood of sustaining damage above a particular threshold due to a specific type of hazard event. It also can be expressed in terms of potential monetary losses associated with the intensity of the hazard.
Runoff That portion of precipitation that is not intercepted by vegetation, absorbed by land surface, or evaporated, and thus flows overland into a depression, stream, lake, or ocean (runoff, called immediate subsurface runoff, also takes place in the upper layers of soil).
Scale A proportion used in determining a dimensional relationship; the ratio of the distance between two points on a map and the actual distance between the two points on the earth’s surface.
Seismicity describes the likelihood of an area being subject to earthquakes.
Special Flood Hazard An area within a floodplain having a 1 percent or greater
Area (SFHA) chance of flood occurrence in any given year (100-year floodplain); represented on Flood Insurance Rate Maps by darkly shaded areas with zone designation that include the latter A or V.
Special Hazard Area Special Hazard Area means an area having special flood, mudslide (i.e., mudflow) and/or flood-related erosion hazards, as shown on a FHBM or FIRM as Zone A, AOA, A1-30, AE, A99, AH, VO, V1-30, VE, V, M, or E.
Stafford Act The Robert T. Stafford Disaster Relief and Emergency Assistance Act, PL 100-107 was signed into law November 23, 1988 and amended the Disaster Relief Act of 1974, PL 93-288. The Stafford Act is the statutory authority for most Federal disaster response activities, especially as they pertain to FEMA and its programs.
Stakeholder Individual or group that will be affected in any way by an action or policy. They include businesses, private organizations, and citizens.
Standard Project Flood A term used by the U.S. Army Corps of Engineers to designate a flood that may be expected form the most severe combination of meteorological and hydrological conditions that is considered reasonably characteristics of the geographical area in which the drainage basin is located, excluding extremely rare combinations. The peak flow for a standard project flood is generally 40 to 60 percent of the probable maximum flood for the same location.
State Coordinating Agency State coordinating agency means the agency of the state government, or other office designated by the Governor of the state or by state statute at the request pf the Administrator to assist in the implementation of the National Flood Insurance Program in that state.
State Hazard Mitigation The representative of state government who is the
Officer (SHMO) primary point of contact with FEMA, other state and federal agencies, and local units of government in planning and implementation of pre- and post- disaster mitigation activities.
Stile A set of stairs to allow access over an obstruction, such as a floodwall.
Stream A body of water flowing in a natural surface channel. Flow may be continuous or only during wet periods. Streams that flow only during wet periods are termed “intermittent streams.”
Structure Something constructed. (see also Building)
Structural Mat Slab The concrete slab of a building that includes structural reinforcement to help support the building’s structure.
Structural Floodplain Those physical or engineering measures employed to modify the way floods behave; examples included dams, dikes, levees, channel enlargements, and diversions.
Structure A walled and roofed building, including a gas or liquid storage tank, that is principally above ground and affixed to a permanent site, as well as a manufactured home.
Subdivision Regulations Ordinances or regulations governing the subdivision of land with respect to things such as adequacy and suitability of building sites and utilities and public facilities.
Subsidence Sinking of the land surface, usually due to withdrawals of underground water, oil, or minerals.
Subsidized Rates Subsidized rates means the rules established by the Administrator involving in the aggregate subsidization by the Federal Government.
Substantial Damage Damage of any origin sustained by a structure in a Special Flood Hazard Area whereby the cost of restoring the structure to its before-damaged condition would equal or exceed 50 recent of the market value of the structure before the damage.
Substantial Improvement Substantial improvement means any reconstruction, rehabilitation, addition, or other improvement of a structure, the cost of which equals or exceeds 50 percent of the market value of the structure before the “start of construction” of the improvement. This term includes structures, which have incurred “substantial damage,” regardless of the actual repair work performed. The term does not, however, include either: (1) Any project for improvement of a structure to correct existing violations of state or local health, sanitary, or safety code specifications which have been identified by the local code enforcement official and which are the minimum necessary to assure safe living conditions or (2) Any alteration of a “historic structure,” provided that the alteration will not preclude the structure’s continued designation as a “historic structure.”
Tornado A violently rotating column of air extending from a thunderstorm to the ground.
Variance Variance means a grant of relief by a community from the terms of a floodplain management regulation.
Venting A system designed to allow floodwaters to enter an enclosure, usually the interior of foundation walls, so that the rising water does not create a dangerous differential in hydrostatic pressure. This is usually achieved through small openings in the wall, such as a missing or rotated brick or concrete block or small pipe.
Vulnerability Describes how exposed or susceptible to damage an asset is. Vulnerability depends on an asset’s construction, contents, and the economic value of its functions. Like indirect damages, the vulnerability of one element of the community is often related to the vulnerability of another. For example, many businesses depend on uninterrupted electrical power – if an electric substation is flooded, it will affect not only the substation itself, but a number of business as well. Often, indirect effects can be much more widespread and damaging than direct ones.
Vulnerability Assessment The extent of injury and damage that may result from hazard event of a given intensity in a given area. The vulnerability assessment should address impacts of hazard events on the existing and future built environment.
Watercourse A natural or artificial channel in which a flow of water occurs either continually or intermittently.
Watershed An area that drains to a single point. In a natural basin, this is the area contributing flow to a given place or stream.
Water Surface Elevation Water surface elevation means the height, in relation to the National Geodetic Vertical Datum (NGVD) of 1929, (or other datum, where specified) of floods of various magnitudes and frequencies in the floodplains of coastal riverine areas.
Water Table The uppermost zone of water saturation in the ground.
Wetlands Areas that are inundated or saturated at a frequency and for a duration sufficient to support a prevalence of vegetative or aquatic life requiring saturated or seasonally saturated soil conditions for growth and reproduction.
Wildfire An uncontrolled fire spreading through vegetative fuels, exposing and possibly consuming structures.
Zoning Ordinance An ordinance under the State or local government’s police power that divides an area into districts and, within each district, regulates the use of land and buildings, height and bulk of buildings or other structures, and the density of population.