Flooding Flashcards
definition of hazard
a dangerous phenomenon, substance, human activity or condition that MAY cause loss of life, injury or other health impacts, property damage, loss of livelihoods and services, social and economic disruption, or environmental damage
definition of disaster
a dangerous phenomenon, substance, human activity or condition that HAS cause loss of life, injury or other health impacts, property damage, loss of livelihoods and services, social and economic disruption, or environmental damage
definition of hazard management
what humans do, or should do, to minimise the effects of hazards
definition of aggravating factors
range of challenges that can exacerbate the effects of hazards, resulting in increased frequency, complexity and severity of disasters
what is hazard severity?
how severe a hazard is based on controls of: duration, frequency, magnitude etc. and can change over time
definition of risk
the potential loss of life, injury or destroyed or damaged assets which could occur to a system, society or a community in a specific period of time, determined probabilistically as a function of hazard, exposure, vulnerability and capability
definition of vulnerability
the characteristics of a person or group and their situation that influence their capacity to anticipate, cope with, resist and recover from the impact of a natural hazard
definition of resilience
a process linking a set of adaptive capacities to a positive trajectory of functioning and adaptation after a disturbance
what factors impact post-disaster recovery?
resources, community size, connectedness vs isolation, duration and intensity, actions and timings of external agencies, attitude and political initiatives influencing confidence
definition of flooding
temporary inundation of normally dry land by water from rivers bursting, surface runoff or tidal or coastal waters
what is pluvial flooding? (flash floods and surface water)
rapid-onset, short duration flooding caused by intense rainfall and in catchment conditions
what is fluvial flooding? (river floods)
occurs due to rivers busting their banks, from widespread/long duration precipitation and melting snow. days to weeks to occur
what is coastal flooding (storm surge)?
impacts low-lying coastal areas, caused by: tides, storm surges, tropical cyclones, high winds and tsunamis
what are flood impacts?
floods can carry mud and debris, sewage, and pollutant. can be destructive to land and built environment. health risks of disease and psychologically
risk equation
likelihood of a hazard occurring x consequences of that hazard occurrence
what is risk avoidance?
avoid the problem and the rewards that may come with it
what is risk reduction?
methods to reduce the likelihood and/or severity of loss
what is risk retention?
accepting loss when it occurs
what is risk transfer?
causing another party to accept the risk e.g. insurance
what is low-land (slow) river flooding?
inundation of low-lying land from burst river banks, caused by excessive long-duration precipitation/snowmelt
what is a floodplain?
areas of frequent natural flooding connected to a river network
what is flash (rapid-onset) flooding?
rapid, sudden low-lying flooding caused by intense rainfall or breaking dam.
how to estimate extreme event occurrences?
through annual probabilities
define return period
the average frequency of occurrence of an event of a particular magnitude e.g. 1 in 100 year event
define annual exceedance probability
the probability that a flood will exceed a give level in any year
benefits of flood mapping
determines impact area both during and post-event, generate flood hazard zone maps and source of data to understand flood models
ways of gathering flood mapping data
remote sensing - LIDAR, drones, social media/crowdsourcing, aerial imagery, satellite imagery, and SAR (synthetic aperture radar)
what are the principles of flood modelling?
- based off past flood events
- model validation from this data
- used for prediction of unseen events
what is the purpose of risk management?
reduce the likelihood of the hazard occurring and the consequences of the hazard
what are the flood management aims?
sustainable development, maximising net benefits from floodplains, minimising loss of life and environmental preservation
what are ways to naturally manage catchment-based floods?
- increasing roughness
- attenuating flows
- infiltrating flows (tree planting)
definition of flood mitigation
human intervention in river catchments which is intended to reduce flood risk through reducing flood likelihoods and impacts
what are flood mitigation structural measures?
protect against flooding through hard engineering, through dams, walls, channnelisation, channel diversions and pumping stations
what are flood mitigation non-structural measures?
management measures such as zonation, planning, proofing homes and localised levees/not involving physical construction
