FEMA 480 CHAPT 1 EXAM
QUESTIONS WITH CORRECT
ANSWERS
/. hydrologic cycle - Answer-circulates water throughout the environment. this process
maintains an overall balance between water and air, on the surface and in the ground -
when gets out of balance causes flooding
/.3 main type of flooding - Answer-riverine, coastal, and shallow
/.Riverine flooding - Answer-watershed is an area that drains into a lake stream or other
body of water- channels are defined features on the ground that carry water through
and out of the watershed (rivers, creeks, streams)- when a channel receives too much
water, excess flows over its banks and into adjacent floodplain
/.overbank flooding - Answer-most common type of flooding in the US
-occurs when downstream channels receive more rain or snowmelt , or blocked by an
ice jam or debris
/.velocity - Answer-v= ft/sec
hilly and mountainous areas have faster moving water- higher velocity
/.flash flooding - Answer-severe storm that drops much rainfall in a short time can
generate a flash flood:
-can also occur in urban areas with more impervious surfaces
- rank first in flood related deaths
-steep slopes and narrow stream more vulnerable
/.Riverine erosion - Answer-river channels change as water moves downstream- force is
made more potent during a flood when the river's velocity increases
/.thalweg - Answer-deepest part of the channel
/.meander - Answer-curve in a channel
- properties on the outside of meanders face a double threat of inundation and
undercutting
/.coastal flooding - Answer-hurricanes and severe storms cause most coastal flooding-
include nor-easters (severe storms on the atlantic coasts
, /.storm surge - Answer-persistent high wind and changes in air pressure push water
toward the shore causing a storm surge
/.coastal erosion - Answer-complex process that involves natural and human-induced
factors
natural: sand sourcesm sand size and density, changes in water level, waves, currents,
tides, and wind - can accrete or recede a shoreline
human - construction of groins or seawalls, dredging
/.Tsunamis - Answer-A giant wave caused by an earthquake on the ocean floor
- usually occur in pacific ocean
/.lake flooding - Answer-lake shores can flood in similar ways to ocean coasts- can
produce waves in some cases
/.Shallow Flooding - Answer-(FEMA 480) Occurs in flat areas with an absence of
channels so drainage is not effective. It generally falls into one of three categories:
sheet flow, ponding, and urban drainage.
/.sheet flow - Answer-inadequate or no defined channel, floodwater spreads out over a
large area at a somewhat uniform depth - intense or prolonged rainfall and cannot soak
into ground
/.ponding - Answer-Runoff that collects in depressions and cannot drain out, creating a
temporary pond
/.urban drainage - Answer-An urban drainage system includes ditches, storm sewers,
retention ponds, and other facilities designed to store runoff or transport it to a receiving
waterway.
-typically designed to handle amount of water expected during a 10 year storm
-levees can block flow of water to the river- pumps can be installed to move the water
past the levee
/.special flood hazards (unusual hazards) - Answer-- closed basin lakes (lakes with no
outlets- seasonal increase in rain, water rises faster than it can drain)
- uncertain flow paths (floods that change channels- alluvial fan: can have numerous
channels that may change locations during the next flood, usually in more mountainous
areas where the base of the valley flattens out-- 3 hazards: velocity and debris,
sediment, channel can move during the flood)>> in arid areas, can have movable
stream beds: high-velocity flood runs through area with sand or loose soil, degradation
(stream channel lowered), aggradation (stream channel filled in), or migration can occur
-dam breaks: these occur for one of 3 reasons: (1) foundation fails due to seepage,
settling, or earthquake, (2) design, construction, materials or operation were deficient,
(3) flooding exceeds the capacity of the dam's spillway
- ice jam: when warm weather and rain break up frozen rivers or any time there is a
rapid cycle of freezing and thawing
QUESTIONS WITH CORRECT
ANSWERS
/. hydrologic cycle - Answer-circulates water throughout the environment. this process
maintains an overall balance between water and air, on the surface and in the ground -
when gets out of balance causes flooding
/.3 main type of flooding - Answer-riverine, coastal, and shallow
/.Riverine flooding - Answer-watershed is an area that drains into a lake stream or other
body of water- channels are defined features on the ground that carry water through
and out of the watershed (rivers, creeks, streams)- when a channel receives too much
water, excess flows over its banks and into adjacent floodplain
/.overbank flooding - Answer-most common type of flooding in the US
-occurs when downstream channels receive more rain or snowmelt , or blocked by an
ice jam or debris
/.velocity - Answer-v= ft/sec
hilly and mountainous areas have faster moving water- higher velocity
/.flash flooding - Answer-severe storm that drops much rainfall in a short time can
generate a flash flood:
-can also occur in urban areas with more impervious surfaces
- rank first in flood related deaths
-steep slopes and narrow stream more vulnerable
/.Riverine erosion - Answer-river channels change as water moves downstream- force is
made more potent during a flood when the river's velocity increases
/.thalweg - Answer-deepest part of the channel
/.meander - Answer-curve in a channel
- properties on the outside of meanders face a double threat of inundation and
undercutting
/.coastal flooding - Answer-hurricanes and severe storms cause most coastal flooding-
include nor-easters (severe storms on the atlantic coasts
, /.storm surge - Answer-persistent high wind and changes in air pressure push water
toward the shore causing a storm surge
/.coastal erosion - Answer-complex process that involves natural and human-induced
factors
natural: sand sourcesm sand size and density, changes in water level, waves, currents,
tides, and wind - can accrete or recede a shoreline
human - construction of groins or seawalls, dredging
/.Tsunamis - Answer-A giant wave caused by an earthquake on the ocean floor
- usually occur in pacific ocean
/.lake flooding - Answer-lake shores can flood in similar ways to ocean coasts- can
produce waves in some cases
/.Shallow Flooding - Answer-(FEMA 480) Occurs in flat areas with an absence of
channels so drainage is not effective. It generally falls into one of three categories:
sheet flow, ponding, and urban drainage.
/.sheet flow - Answer-inadequate or no defined channel, floodwater spreads out over a
large area at a somewhat uniform depth - intense or prolonged rainfall and cannot soak
into ground
/.ponding - Answer-Runoff that collects in depressions and cannot drain out, creating a
temporary pond
/.urban drainage - Answer-An urban drainage system includes ditches, storm sewers,
retention ponds, and other facilities designed to store runoff or transport it to a receiving
waterway.
-typically designed to handle amount of water expected during a 10 year storm
-levees can block flow of water to the river- pumps can be installed to move the water
past the levee
/.special flood hazards (unusual hazards) - Answer-- closed basin lakes (lakes with no
outlets- seasonal increase in rain, water rises faster than it can drain)
- uncertain flow paths (floods that change channels- alluvial fan: can have numerous
channels that may change locations during the next flood, usually in more mountainous
areas where the base of the valley flattens out-- 3 hazards: velocity and debris,
sediment, channel can move during the flood)>> in arid areas, can have movable
stream beds: high-velocity flood runs through area with sand or loose soil, degradation
(stream channel lowered), aggradation (stream channel filled in), or migration can occur
-dam breaks: these occur for one of 3 reasons: (1) foundation fails due to seepage,
settling, or earthquake, (2) design, construction, materials or operation were deficient,
(3) flooding exceeds the capacity of the dam's spillway
- ice jam: when warm weather and rain break up frozen rivers or any time there is a
rapid cycle of freezing and thawing
