1. FEMA 480 - Unit 3 Exam Questions
And Answers
/. Base flood / 100-year flood - Answer-The one-percent annual chance flood. A 100-
year base flood is defined as having a one-percent chance of being reached or
exceeded in any single year. It's a flood that has a one-percent chance of occurring in
any given year. The base flood is informally referred to as the 100-year flood, is the
national standard used by the NFIP. It was chosen as a compromise between a more
frequent flood (such as 10 percent change) and a more infrequent flood say, a 0.1-
percent chance flood).
/.Probability - Answer-A statistical term having to do with the size of a flood and the
odds of that size of flood occurring in any year.
/.Base floodplain / Special Flood Hazard Area (SFHA) - Answer-The land area covered
by floodwaters of the base flood
SFHA is designated as Zone A, AE, A1-30, AO, AH, V. VE or V1-30 depending on the
amount of data available
This is the area where the NFIP's floodplain management regulations must be enforced
by the community, and where the mandatory flood insurance purchase requirement
applies.
/.Base Flood Elevation (BFE) - Answer-The computed elevation to which floodwater is
anticipated to rise during the base flood
/.the national flood insurance act of 1968 directed the Federal Insurance Administration
to... - Answer-identify all floodprone areas within the US and establish flood risk zones
within floodprone areas
/.Flood Hazard Boundary Map (FHBM) - Answer-Prior to 1986, this was supplied to
communities. Official map of a community issued by FEMA, where the boundaries of
the flood, mudflow, and related erosion areas having special flood hazards have been
designated. The FHBM is generally the initial map provided the community and is
eventually superseded by a FIRM. The FHBM was prepared without the benefit of
detailed studies or hydraulic analyses and contains no BFEs.
- based on approximate studies
/.flood insurance study (FIS) - Answer-(FEMA 480) A report published by FEMA for a
community issued along with the community's FIRM. The study contains such
background data as the base flood discharges and water surface elevations that were
used to prepare the FIRM.
, **FIS is a compilation and presentation of flood risk data for specific watercourses,
lakes, and coastal flood hazard areas
-conducted under standards set by FEMA for the NFIP
-FEMA got more money to perform more detailed studies and went from FHBMs to FIS
and FIRMs
/.the study has 3 components - Answer-1) FIS report
-includes an appraisal of community's flood problems (prupose of study, historic floods,
are and flooding sources, engineering methods)
-a vicinity map
-tables summarizing various flood hazard data
-computed flood profiles for various recurrence probabilities (10, 50-, 100-, 500 yr)
2) the FIRM
3) Prior to 1986, FHBM
/.Flood profile - Answer-A flood profile is a graph of the flood elevations along the
centerline of a stream. The horizontal scale is the length of the stream. The vertical
scale is the elevation of ground, water surfaces, etc. The flood profile in the FIS always
shows the profiles for the base or 1% annual chance (100-year) flood event.
/.Hydrology - Answer-Quantity of water
A science dealing with the distribution and circulation of water in the atmosphere, on
land surfaces, and underground, is used to determine flood flow frequencies. The study
of a watershed's behavior during and after a rainstorm is, therefore, hydrology.
Hydrologic analysis determine the amount of rainfall that will stay within a watershed -
absorbed by the soil, trapped in puddles, etc.- and the rate at which the remaining
amount of rainfall will reach the stream.
/.what type of flooding uses hydrology studies? - Answer-Riverine-
-occurs in rivers, streams, ditches, or other waterways that are subject to overbank
flooding, flash floods, and urban drainage
-riverine studies involve the collection and analysis of info about the river's watershed
/.Runoff & Discharge - Answer-Rainfall that reaches a stream. Increased runoff will
increase flood discharge. Discharge is the amount of water flowing down a stream
channel. Discharges are measured in cubic feet per second or cfs. Data for this
measurement is taken by stream gauges at specified locations along a given stream
also known as gaging stations.
Runoff and discharge rates very depending on soil type, ground slope, land use, and
the presence of storm sewers.
/.Cross Sections - Answer-A graphical depiction of the stream and the floodplain at a
particular point along the stream. It is taken at right angles to the flow of the stream. At
each cross section, the engineer has accurate information on the size and geometry of
the channel, the shape of the floodplain, and the changes in ground elevation.
And Answers
/. Base flood / 100-year flood - Answer-The one-percent annual chance flood. A 100-
year base flood is defined as having a one-percent chance of being reached or
exceeded in any single year. It's a flood that has a one-percent chance of occurring in
any given year. The base flood is informally referred to as the 100-year flood, is the
national standard used by the NFIP. It was chosen as a compromise between a more
frequent flood (such as 10 percent change) and a more infrequent flood say, a 0.1-
percent chance flood).
/.Probability - Answer-A statistical term having to do with the size of a flood and the
odds of that size of flood occurring in any year.
/.Base floodplain / Special Flood Hazard Area (SFHA) - Answer-The land area covered
by floodwaters of the base flood
SFHA is designated as Zone A, AE, A1-30, AO, AH, V. VE or V1-30 depending on the
amount of data available
This is the area where the NFIP's floodplain management regulations must be enforced
by the community, and where the mandatory flood insurance purchase requirement
applies.
/.Base Flood Elevation (BFE) - Answer-The computed elevation to which floodwater is
anticipated to rise during the base flood
/.the national flood insurance act of 1968 directed the Federal Insurance Administration
to... - Answer-identify all floodprone areas within the US and establish flood risk zones
within floodprone areas
/.Flood Hazard Boundary Map (FHBM) - Answer-Prior to 1986, this was supplied to
communities. Official map of a community issued by FEMA, where the boundaries of
the flood, mudflow, and related erosion areas having special flood hazards have been
designated. The FHBM is generally the initial map provided the community and is
eventually superseded by a FIRM. The FHBM was prepared without the benefit of
detailed studies or hydraulic analyses and contains no BFEs.
- based on approximate studies
/.flood insurance study (FIS) - Answer-(FEMA 480) A report published by FEMA for a
community issued along with the community's FIRM. The study contains such
background data as the base flood discharges and water surface elevations that were
used to prepare the FIRM.
, **FIS is a compilation and presentation of flood risk data for specific watercourses,
lakes, and coastal flood hazard areas
-conducted under standards set by FEMA for the NFIP
-FEMA got more money to perform more detailed studies and went from FHBMs to FIS
and FIRMs
/.the study has 3 components - Answer-1) FIS report
-includes an appraisal of community's flood problems (prupose of study, historic floods,
are and flooding sources, engineering methods)
-a vicinity map
-tables summarizing various flood hazard data
-computed flood profiles for various recurrence probabilities (10, 50-, 100-, 500 yr)
2) the FIRM
3) Prior to 1986, FHBM
/.Flood profile - Answer-A flood profile is a graph of the flood elevations along the
centerline of a stream. The horizontal scale is the length of the stream. The vertical
scale is the elevation of ground, water surfaces, etc. The flood profile in the FIS always
shows the profiles for the base or 1% annual chance (100-year) flood event.
/.Hydrology - Answer-Quantity of water
A science dealing with the distribution and circulation of water in the atmosphere, on
land surfaces, and underground, is used to determine flood flow frequencies. The study
of a watershed's behavior during and after a rainstorm is, therefore, hydrology.
Hydrologic analysis determine the amount of rainfall that will stay within a watershed -
absorbed by the soil, trapped in puddles, etc.- and the rate at which the remaining
amount of rainfall will reach the stream.
/.what type of flooding uses hydrology studies? - Answer-Riverine-
-occurs in rivers, streams, ditches, or other waterways that are subject to overbank
flooding, flash floods, and urban drainage
-riverine studies involve the collection and analysis of info about the river's watershed
/.Runoff & Discharge - Answer-Rainfall that reaches a stream. Increased runoff will
increase flood discharge. Discharge is the amount of water flowing down a stream
channel. Discharges are measured in cubic feet per second or cfs. Data for this
measurement is taken by stream gauges at specified locations along a given stream
also known as gaging stations.
Runoff and discharge rates very depending on soil type, ground slope, land use, and
the presence of storm sewers.
/.Cross Sections - Answer-A graphical depiction of the stream and the floodplain at a
particular point along the stream. It is taken at right angles to the flow of the stream. At
each cross section, the engineer has accurate information on the size and geometry of
the channel, the shape of the floodplain, and the changes in ground elevation.
