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Hazard Planning
Planning for Hazardous Events (flood, earthquake, etc).
Question | Answer |
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4 Parts to a Hazard Mitigation Plan | 1) Mitigation Plan; 2) Preparation Plan; 3) Response Plan; 4) Recovery Plan. Natural disasters are only considered "disasters" if they affect human development. If it occurs somewhere unpopulated, it is not considered hazardous or a "natural disaster" |
3 steps to hazard mitigation planning | 1) map the area 2) consider how each potential hazard will affect key factors 3) devise mitigation strategies |
Steps (broken out) | |
1. Map the Area | By mapping the area, planners can more easily identify which areas are exposed to the most risk. A map of fault lines can help identify earthquake-prone areas while FEMA flood maps show areas that are especially susceptible to flooding. |
2. Consider how each potential hazard will affect key factors | Key factors include the population at large, local economies, buildings, utilities, transportation systems, and various natural features. |
3. Devise Mitigation Strategies | The goal of any mitigation strategy is lessening the potential impacts of hazardous event. Common mitigation strategies include the following: educating the public about the hazard; reserving hazardous zones for open space; not constructing in haz zones |
Earthquakes | HAZUS (FEMA mapping system). Build buildings according to the National Earthquake Hazards Reduction Project (NEHRP). 1) ground motion; 2) surface faulting; 3) seismic activity; 4) failure (liquefaction) |
Floodplain | an area of land with at least a 1% chance of annual flooding (aka 100-year flood plain). Use Flood Rate Insurance Map (FIRM) - FEMA map. |
Floodways | Channels that must remain open and unobstructed in order to allow proper flooplain drainage. |
Base Flood Elevations | Min dist(in feet) a residential area must be elevated above floodplain floor. Flood mitigation strategies: 1) elevating structures; 2) construction buildings so flood waters can pass through w/ min damage; 3) moving existing structure to higher ground |
Hurricanes | Evacuation easiest strategy bc hurricanes are easy to predict. FEMA maps. Sea Lake Overland Surge from Hurricanes (SLOSH) Model. Store resistant building techniques. Tying down outdoor furniture and manufactured homes. |
Wildfires | Wildland/urban interface (UAI). Planners should consider: 1) site topography and location; 2) building materials and design; 3) type of plant growth for landscaping; 4) emergency vehicle access; 5) water supply access; 6)fire protection on-site. |
Sinkholes | Occur when soil moves downward through fractures in the underlying bedrock, creating surface depressions. Most commonly found in regions possessing karst topography (underground caves, soluble rock, underground streams, and springs). |
Collapse sinkholes | Bowl-shaped funnels that extend almost vertically down beneath the subsurface. |
Subsidence sinkholes | Do not involve any collapse or funneling into the subsurface; rather, it occurs when the land gradually sinks. |
Landslides | Causes: rainfall, earthquakes, human activities such as irrigating excessively, building hillside septic tanks, removing vegetation, placing landfills on unstable slopes, cutting slopes at overly steep angles, redirecting storm runoff onto unstable slope |
Erosion | Riverine and coastal regions. Property loss or damage, erosion of dams, levees, and natural barriers = flooding. Farmlands lose up to 5 tons of soil per acre/year. Mitigation strategies: maintain and plant vegetation. Use swales and mulching. |
Sedimentation | The depositing of sediments onto an area via wind/rain/etc. Mitigation strategies: plant vegetation to hold down soil; don't place soil near waterways; use sedimentation trapping; create buffer strips; avoid excessive runoff = no impervious surface |
Hazmat Vulnerable Zone | Everything within the boundary of a leakage plume from an underground storage tank or air hazmat. When hazmat is being transported, the vulnerable zone is constantly changing. |
Comprehensive Environmental Response, Compensation, and Liability Act (CERLA) | 1980. Mandates that hazardous materials are given secondary containment. |
Resource Conservation and Recovery Act (RCRA) | 1984. Requires the development of regulatory programs for storing hazardous materials. Owners of hazmat storage tanks must monitor them and clean up any leaks. Many state govs create trust funds to assist storage tank users in addressing leaks and spills. |