flood risk Flashcards
factors affecting flood risk
-tropical storms
-storm surges/tsunami
-low lying land
-subsidence
-removing vegetation
-vulnerable urban space
-sea level rise
low lying areas at risk of flood
(1) delta regions
(2) SIDS (small island developing states like Maldives)
(3) drained marsh lands and estuaries
figure describing delta regions in relation to flood
50% estimated increase of flooding over the next century
how much do mangroves reduce wave height by
40%
for every 1km inland, how much do mangroves reduce height of storm surge by
0.5m
example of vulnerabilities on risk equation (to floods)
-population (size, density, rate of growth)
-property, infrastructure
-agriculture
-businesses
example of hazards on the risk equation (relation to floods)
-flood scale
-flood magnitude
-flood frequency
example of capacity to cope on the risk equation (relation to floods)
-coastal management (wealth, planning and sea defence)
-warning, monitoring, education
-insurance (developing countries lack)
examples of risk on the flood risk equation (relation to floods)
-economic risk= how many/type of properties, businesses, income and jobs
-social risk= death, injury, loss of farmland and drinking water due to saltation
-displacement
-environmental refugees
what exacerbates flood risk
-combo of human and physical factors
what 3 things combine to make a dangerous storm surge
-high onshore wind speed (higher sea level if same time as high tide)
-very low atmospheric pressure (rise of 1cm for ever 1mb drop)
-shape of the coastline (funnel shaped coasts = greater surge)
whats a funnel shaped coast and why does it have a greater surge
-they have low of shore gradient
-land either side of the beach narrows further inland so water is pushed higher
when is a tsunami created
-when a large mass of water is suddenly displaced
-e.g. due to underwater landslide or earthquake moving sea bed vertically
