Textbook Notes NFIP Flashcards
3 major categories of floods
riverine, coastal, shallow
most common type of flooding
overbank flooding
downstream channels receive excess water or channel is blocked. then, water overloads and flows out
what causes most coastal flooding
hurricanes and severe storms
what is a tsunami
caused by underwater earthquake or volcano
3 types of hydrodynamic forces
frontal
drag
eddies or negative pressure (suction to downstream side)
1960 and earlier- types of projects
structural flood control projects primarily
when was NFIP created
1968
establish insurance
distribute responsibility
set standard for development
begin floodplain mapping
when was national flood insurance act created
1968
unified national program for floodplain management
floodplain management strategies
1 - modify human susceptibility to flood damage
2 - modify impact of flooding
3 - modify flooding itself
4 - preserve and restore natural resources
when was the Flood Disaster Protection Act passed
1973
prohibit most building assistance in floodplains of non participating communities
how much total USA land area is floodplain
7%
which department is FEMA administered by
Department of homeland security
how fast is a high velocity flood
5 ft/s or greater
most important amendment to FEMA
1994 - National Flood Insurance Reform Act
CRS establish, increase max coverage, start grant program
when is federal funding available
in communities that agree to regulate development in mapped floodplains
NFIP based on agreement between Federal Gov and Communities
3 purposes of FEMA maps and data
basis for regulating new flood-prone construction
rating insurance policies
determine when flood insurance must be purchased as a condition of a loan
what are the 2 types of FEMA maps
FHBM (approximate)
FIRM (based on FIS, more accurate)
3 things can occur if community does not follow NFIP
new buildings subject to flood damage
insurance is very expensive
FEMA can impose sanctions
Community Role in NFIP
enact and implement floodplain regulations
issue/deny floodplain development permits
inspect development for compliance with ordinance
maintain record of floodplain development
assist in revision of floodplain maps
inform residents of flood hazardsn
state role in the NFIP
ensure communities have legal authority to enforce regulation
establish minimum regulations consistent with NFIP
provide technical assistance to local gov
coordinate with various state agencies that affect the NFIP
can also enforce regulations for state owned properties. often done through governors executive order. may have own regulations
NFIP are on what ratio of cost share
under CAP - NFIP funds are available 75/25 %
to help state provide technical assistance to communities
federal role in NFIP
FEMA within department of homeland security administers NFIP through regional offices and mitigation division
assists state NFIP coordinating criteria
assess community compliance
advise local officials
review and adopt new maps
approve community regulations
administers the insurance portion. Sets insurance rates, establishes coverages, monitors claims, markets flood insurance
how to join the NFIP
- community adopt letter of intent to participate with FEMA
- submit and adopt a floodplain management ordinance that meets or exceeds NFIP
then, communities receive a FIRM. They get 6 months to adopt the ordinance,
what happens if a community does not comply
CAV or CAC inspects.
FEMA has 3 recourses: reclassification under CRS, probation, suspension
what does the CRS do
community rating system provides discounts on insurance premiums for communities exceeding NFIP
if not comply, reclassified to class 10
probation
formal notification of non-compliance
prior, 90 day notice for specific violations
$50 for policies sold or renewed during this time
sanctions for non-participation in NFIP
no flood insurance available/ cannot be renewed
no federal grants / loans for construction in SFHA
no disaster assistance for repair in SFHA
federally insured lending institutions (banks) must notify applicants that there is a flood hazard & cannot get insurance
NFIP base flood, also called
1% flood
100 year flood
base floodplain
special flood hazard area (SFHA)
when year was the national flood insurance act & what did it do
1968
identify floodprone areas
establish flood risk zones within floodprone areas
today, FEMA does this
who set the FIS standards
FEMA
flood hazard boundary maps vs FIRM vs FIS
FHBM - approximate map - used prior to 1968
FIRM - detailed map
FIS - detailed studies
what is a datum and who uses it
common vertical elevation refrence
surveyors
which datum do we use in FIS
national geodetic vertical datum (NVGD) of 1929
OR north americal vertical datum (NAVD) of 1988
based on mean sea level
when looking at a flood profile, what is the start/end points
start at mouth of stream or notable location
then, look upstream
slope increases generally from left to right
what is a bridge symbol in the flood profile
I
the bottom of the I is the low chord (lowest beam)
top of the I is the top of a solid bridge railing
what is the base map also called
topographic map
contour map
shows BFE from cross sections and profiles
what does the floodway/base floodplain/SFHA include
floodway + fringe
AE zone or A1-30
development outside = no analysis needed
permit needed to develop in flood fringe for building to be elevated to BFE
floodway development allowed if no rise in BFE occurs - compromise standard is 1’ increase
floodway development discouraged
what are coastal floods caused by coastal storms called
storm surge
caused by air pressure changes and strong winds
computer programs produces stillwater flood elevations (floods, not wave elevations)
wave runup vs wave setup
runup - when waves hit the shore and water is moving with such force it keeps traveling inland - flood land areas higher than stillwater elevation
setup - additional elevation of water surface over normal surge elevation - caused by onshore mass transport of water by wave action
what does the coastal flood engineer study in riverine vs coastal flood
riverine - cross section
coastal - transects (elevation of ground onshore and offshore)
what is underwater topography called
bathymetry
what is the BFE for coastal area
stillwater elevation + wave runup OR wave crest elevation (whatever is greater)
what defines a coastal high hazard area
BFE wave heights are 3’ or more (3’ was chosen because 3’ wave can break a wall panel away from a floor)
inland limit of the primary frontal dune
eroded ground profile 3’ below computed runup elevation
how is shallow flooding defined
average flood depth 1to 3 ft where defined channel does not exist
what is the ERM or RM on a flood map
(elevation) reference mark
what is the coastal barrier resource system
coastal barrier resource system (CBRS) is shown on maps, called CBRA areas
established by the coastal barrier resource act of 1982 and coastal barrier improvement act of 1990
protects CBRA by prohibit expenditures of federal funding (including insurance) for new/improved buildings in mapped areas
BFE on FIRM vs FIS
FIS - to 1/10 foot
FIRM - nearest hole number
note: add 0.4ft to FIRM to get FIS number
what does zone X show
area protected from base flood due to structure
how many digits is each item in the title block
6 - NFIP community ID
5 - map number (first 2 is state, next 3 is country)
where to get BFE from for coast
FIRM + 0.4’
where to get BFE for lakes and reservoirs
the table
order of precedence identifying for BFE
- floodway data table (riverine) and summery of stillwater elevations table (lake)
- profile
- FIRM (riverine)
note, FIRM is only source of BFE for coastal and AO and AH zones
what does an asterisk mean on a map
no flood hazard identified or map is entirely 1 flood zone and panel not printed
how to order a map
maps are provided by Map Service Center to local Gov officials for free
only FIRM will be sent, unless FIS and floodway maps requested
who can request a map change
engineer who knows FEMA guidlines
small projects like channel clearing, retention basins no not measurably affect base flood
community has 6 months to make map change after affecting BFE
limited map maintenance project (LMMP)
small study, limited in size and cost
used in unnumbered A zones
map revision
base challenges to flood elevations
incorporate new data
reflect fill
change floodplain or boundaries
include new flood data
map amendment
remove area in SFHA
not challenge FIS - no fees
what can FEMA form MT-1 do
LOMA
CLOMA
LOMR-F
CLOMR-F
professional engineer / surveyor required
what can FEMA form MT-2 do
LOMR
CLOMR
physical map revision
professional engineer / surveyor required
what can FEMA form MT-EZ do
LOMA
LOMR-F
the shortest and simplest form - but land surveyor needed to certify elevation data
no professional engineer / surveyor required
which chapter is NFIP regulations found
Ch 44 of CFR (code of federal regulations)
part 59 and 60
(mapping parts 65 and 70)
which level commonly creates flood model
state NFIP coordinators create state model
60.3 (a)
no maps
60.3 (b)
map with approximate A zone
60.3 (c)
FIRM with BFE
60.3 (d)
FIRM with BFE and floodway shown
60.3 (e)
FIRM with coastal high hazard area (V zones)
what is the community rating system (CRS)
part of NFIP that rewards (credits) communities that implement programs that exceed minimum
basic rule 1
use latest flood maps and data published by FEMA (44 CFR 60.2h)
who can approve strictor regulatory standards
FEMA regional office
if approximate A zone with no elevation data nor identified floodway, all new subdivisions/development of what size need base flood elevation data
50 lots or 5 acres
44 CFR 60.3(b)
if a small development (less than 5 acres or 50 lots) develops, it must:
site is reasonably safe from flooding or minimizes flood damages by set elevation you determine
determine elevation by: walking site (put house on highest point), use historical records of flood of record, require flood protection at 5’ above grade, or require development of a BFE
how long after a developer prepares a detailed study to submit to FEMA
6 months
what is advisory flood hazard data
FEMA issued data after flood showing FIRM or FIS underestimated hazard
recommended to reasonably utilize this data. but not required
basic rule 2
a permit is required for all development in SFHA on FIRM
if not FIRM, then all development requires permit
44 CFR 60.3(a)(1)
what is development
any man made changes to improved or unimproved real estate
construction, filling, paving, mining, land clearing
what does a building permit include
filling, excavation, storage, repairs, temporary stream crossing, gov activities like roads
44 CFR 60.3(a)(2)
requires all NFIP communities ensure all other federal and state permits have been obtained
which development activities require state permit
construction in coastal zone / floodway
stream crossing of navigable rivers
installation of septic system
subdivision standards or lot filing
mobile home tie down requirements
public health facilities (hospitals/nurising homes)
alteration of sand dunes
operating landfill storage
common federal regulations that require a permit
USACE section 404 - wetland filling
USACE section 10 - navigable waterways
US coast - bridge that affect navigation
US fish and wildlife - section 7 and 10 of endangered species act of 1973
basic rule 3
development must not increase flood hazard on other properties
ex: riverine, where dam may divert water onto other properties - therefore communities adopt floodway where flows are sensitive to change
when is encroachment review (analysis to determine if project will increase flood heights) required
all projects in floodway - zero increase allowed
development projects in flood fringe do not increase flood heights above allowable level - so not needed
44 CFR 60.3(d)(3)
encroachment certification
no rise certification
development will not affect flood heights
what is a conveyance shadow
area upstream and downstream of existing building or other obstructions to flood flows
water flows around existing larger object, so new structure will not change flow
if small project in conveyance shadow, no rise cert not required
treat riverine floodplain as floodway if no FIRM:
requires same encroachment (no rise)certification
if no floodway, review determines cumulative effect of development with all other development (increase BFE less than 1 ft)
when is there an allowable increase in flood height
dam
requires conditional FEMA approval:
CLOMR, evaluations of alternatives, legal notice to property owners, CEO of other communities not affects, no structures located in areas affected by increased BFE, revision of BFE
basic rule 4
new, substantially improved, substantially damaged buildings must be protected from damage by base flood
residential vs nonresidential standards
residential - elevated above BFE if in floodplain
non - elevated OR floodproofed
3 methods to elevate residential structure so lowest flood (basement included) is at or above BFE in Zaone A1-30, AE, and AH
fill
piles, posts, piers, columns
walls or crawlspace
requirements for below grade residential crawlspace
interior grade no more than 2’ below lowest adjacent grade
height (interior grade to top of wall) does not exceed 4’
not considered basements
note 3 things about NFIP requires lowest floor of building above BFE
lowest floor includes basement
minimum is to elevate to BFE
A zones, lowest floor is measured from top of the floor - but all portions of building below BFE must be flood resistant and utility systems above BFE
allowable uses of enclosures
building access, vehicle parking, storage
requirement for openings
bottom of opening no higher than 1’ above grade
openings on at least 2 walls
net area 1 sq in for every sq ft
what is floodproofing
in building, below BFE:
walls are watertight
structural components can resist hydro forces
utilities protected from flood damage
most floodproofing appropriate where floodwaters less than 3’ deep
height requirement for floodproofing
NFIP requires to BFE
however, for insurance, 1’ subtracted from floodproofed elevation (therefore, for insurance, 1’ above BFE required)
basement definition
area that is subgrade on all sides
NOT basement - walkout, daylight, terrace levels
ARE basements - cellars, garden apartments / split level with lowest floor (if residential, requires elevation on fill)
when is basement exception allowed
flood depth less than 5’
velocity less than 5 ft/s
adequate warning time
appropriate construction requirements
design certified by registered engineer
anchoring required when
flood flows faster than 5 ft/s
coastal areas subject to waves and high winds
mobile homes
when can a structure be wet floodproofed
detached garages, storage
meet requirements:
variance obtained
building only for parking or storage
required openings for water
flood resistant materials below BFE
anchored building
utilities elevated or floodproofed
elevation requirement for mobile homes
lowest floor at/above BFE
parts lower than BFE must be flood resistant materials
often have tie down regulations (if pre FIRM, then anchoring requirement)
examples of permanent foundations
reinforced piers
posts
piles
poured concrete walls
compacted fill
recreational vehicles on SFHA
meet elevation and anchoring
on site less than 180 consecutive days
ready for highway use
AO zone requirements
new construction elevated as high as depth on communities FIRM
OR 2’ if no depth is specified
when are adequate drainage paths required around structures to guide water away
AO and AH zones
basic rule 5
due to wave heights, V zones have special building standards on top of A zones
building location for V zones
located landward of the reach of mean high tide
cannot be over water
recommended not on sand dunes
elevated on columns/posts/pilings only
within V zones, what is the controlling elevation
bottom of lowest horizontal structural member of lowest floor
how to account for wind in V zonesd
cross bracing and proper connections
use piles of wood, steel, pre cast concrete (not block columns)
breakaway walls
used for parking vehicles, or building access, or storage
constructed of flood resistant material
max area enclosed by solid breakaway walls
300 ft
after that, it’s a large enough area to habitat
if subdivision site is floodprone, builder should
locate structures on highest natural ground
utilities and facilities located to minimize flood damage
provide adequate drainage for each building site
water and sewer system requirements
minimize infiltration
manholes elevated above BFE or have seals to prevent leaking
pumping station electrical pad above BFE
watercourse alteration should:
not increase flood risk of themself or adjacent community
CLOMR for large scale projects
why not just say “no” to building in the floodplain
taking - action from gov that relieves a person of his property without payment
if taken, and owner has been deprived of his property use, called inverse condemnation - here, gov must compensate property owner
NFIP criteria do not prohibit the development of a floodplain site (but cannot increase flood heights) - this is NOT taking
what is eminent domain
under eminent domain, gov can acquire properties with owners agreement if for public use (ex parks, not increasing flood heights)
who enacts state regulations governing shoreline development
oceans/bay coasts - state coastal zone management program
great lakes - lakeshore regulatory standards / permits as part of state shoreline management program
what is planned unit development (PUD)
developers have flexibility in planning entire area - where to put structures - how to divide lots
can even have open space for recreation or stormwater management - normally this is the floodplain area - is CRS credit
what is low density zoning
community zones a floodplain for low density use
ex: have 1 farm on 10 acres vs a subdivision
get CRS credit
what is freeboard
additional height above BFE
not required by NFIP
encouraged 1’ freeboard
get CRS credit
what is a critical facility
toxic material storgae
hospitals, nursing homes
police stations
utility facilities
SHOULD not be located on floodplain - but if it is, then elevate to 500 yr standards SHOULD be required
if federal funding is required, EO 11988 requires site evaluations
what is a temporary moratorium
temporary hold in development in floodplain
what special maps are used for coastal erosion
erosion rate maps - 30, 60, 100 year maps
erosion zone = annual rate of erosion * number of years protection is provided
erosion advisory standards (not NFIP requirement)
buildings located landward of 30 year erosion zone
deeper piling and special foundation provisions
traffic restriction on sand dunes
examples of closed basin lakes
no outlet (great salt lake) or inadequate outlet (great lakes)
what are examples of uncertain flow paths
alluvial fans
moveable bed streams
what is the area downstream of a dam break
dam breach inundation area
standards for ice jams
if no detailed study, SHOULD use historic ice jam on record + 1 or 2 feet of freeboard
mud flow regulatory standards
should prepare flow hazard studies
potential regulatory measures:
design work with natural flow channels & not cut across
engineered foundations on compacted fill or pilings
avoid building below steep slopes
have debris basin, channels to keep debris away from houses
direct runoff away from unstable areas
enforce grading that minimizes disruption of natural drainage wats
2 basic strategies to protect floodplain
preservation
restoration
federal regulation to protect resources
national environmental policy act (NEPA) - requires environmental impact study
EO 11988 - if project is in floodplain, then move to feasible alternative if possible
what is section 404 of Clean Water Act (CWA)
administered by USACE and US EPA
regulates discharge of dredge or fill in US waters and wetlands
what is the endangered species act of 1973
federal
federal agencies cannot undertake or assist project that would adversely affect endangered species
requires incidental take permit - when rare species habitat taken/impacted by non federal activity
what is an ordinance
law passed by local government
also called by law
what is statutory authority
powers granted and limited by state law to community
also called enabling legislation
grant community extent of authority
what is home rule
when large communities are authorized to do anything that is not prohibited by statute
floodplain regulations are found in these 4 types of regulations
zoning ordinances (separate districts and overlay zoning)
building code (construction standards for a building, NEPA 5000 or I-Code)
subdivision regulations (how land is divided)
sanitary regulations
stand alone ordinances
what powers does the state grant authorities
police powers to adopt, administer, enforce local codes & regulations
duties of floodplain administer
responsible for ensuring development complies with regulations
understand regulations
ensure permits applied for
correct violations
process permit applications
coordinate with other programs
ensure project built according to approved permits
take enforcement action
keep records
maintain and update flood data and maps
update the ordinance
what starts the permit process
submission of development permit application
can have pre-application meeting
review of permit applications should include
all administrative forms are completed correctly and signed
review site plans, grading, and building design for completeness
ensure all necessary certifications and included and signed
all federal and state permits obtained
copies of appropriate parts of the application package to other departments for review
what 4 situations would require a certified document with a permit application
floodway encroachment - engineer certifies no increase in BFE. If riverine, not exceed 1’ increase in flood height - no rise cert
floodproofed building - nonresidential
enclosure below lowest floor
V zone construction - engineer certify design and breakaway walls
review for compliance includes
examine site information
review building plans (in SFHA, BFE or higher)
have community engineer review engineering docs
when is floodplain development permit required
planned structure / work within SFHA
if some of the land is in the SFHA, but the building itself is not, submit LOMA to remove building from SFHA and get better insurance rates
how many inspections are recommended per project
3
when do you conduct the first inspection
before ground is broken, after staking
check for: location of floodplain, setbacks from lot lines, floodway encroachment
when do you conduct second inspection
just before installation of lowest floor
check for: height of building against permit application height listed, foundation type, fill compaction & slope, building location, crawlspace, encroachments
when to conduct the third inspections
as project nears completion
check for: foundation has not been altered, as built information or floodproof cert, enclosures, no utility below lowest floor
if pass, get certificate of occupancy
what is maximum enclosure size for a private property that does not allow inspections
300 sq ft
recommendation only
what does adequate, uniform, fair enforcement mean
development must have permit
permit must be built according to approved plans
what administrative tools do you have
stop work or revoke permit
withhold certificate of occupancy
maximum fine per offense issued
what is section 1316 of National Flood Insurance Act
authorizes FEMA to deny flood insurance to property in violation of floodplain regulations
4 special cases, specified by state law
appeals
special uses
variances
boards
what situations qualify for variance
good and sufficient cause - land only
hardship
historic buildings
functionally dependent use (must be located close to water)
variances are not allowed in floodway if it cases increase in BFE
how high must a building be floodproofed to receive rating credit
1’ above BFE
what is a special NFIP requirement for coastal communities in V zones
buildings anchored to resist wind and water simultaneously
which certification is it that riverine floodplains must be free of encroachments that increase flood levels
no rise certification
significant improvement basic rule
if the cost of improvement or cost of repair exceeds 50% of the market value of the building, it must be brought up to current floodplain management standards
includes post FIRM building that used to be at BFE, but a map change increased BFE & now it has to be elevated
how many years should be accounted for in substantial improvement
the entire life of the structure
seperate projects = 50%, then substantial improvement
substantial improvement formula
cost / market value >= 50%
2 exemptions to substantial improvement rule
improvements to correct code violations do not county towards cost of improvement
historic buildings
market value definition
price a willing buyer and seller agree upon
only about structure (not land/landscaping/detached structures)
does not include plans/survey costs/permit fees
rehabilitation definition
improvement made to an existing structure that does not affect external dimensions of the structure
if substantial improvement, then the existing structure must be elevated or basement filled to meet elevation standard
addition definition
improvement that increases the square footage of the structure
if substantial improvement, only the addition must be floodproofed/elevated (if nothing done to original structure) - but if the common wall is demolished, then entire structure must be elevated - same as lateral addition
if A zone, both addition and structure must be elevated & for vertical addition
substantial improvements for post FIRM building must be elevated to what BFE
current ordinance - even if it’s higher than original BFE
so, maybe addition would be higher (current BFE) then the rest of the house (previous BFE)
2 key points of substantial damage
damage can be from any cause
substantial damage rule applies to all building in flood hazard area, regardless whether the building has flood insurance
repair / market value >= 50%
substantial damage determined regardless of actual cost to owner - use market prices to determine damage cost
reconstruction definition
entire structure was destryed, damaged, demolished and new structure is build on old foundation or slab
also when existing structure moved to a new site
when was increased cost of compliance (ICC) first offered
June 1, 1997
only for flood damage
up to $30,000 per structure
some cases, file if building repetitively flooded, 2+ claims averaging 25%+ of building value in 10 year period
3 special situations for substantial improvement / damage
exempt costs (plans/permit fees/repairs for health safety or to prevent damage to building)
historic buildings (project must maintain historic status)
code violations (involuntary improvements before permit applied for or damage occurred, only exempt items specifically required by code)
where does a home owner buy flood insurance
from local property insurance agents (not FEMA)
what percent of building coverage can be used for a detached garage
10%
what is content coverage
insurance for removable items inside an insurable building
what is a basement
any area of a building with floor below ground level (subgrade) on all sides
how long after you purchase flood insurance before it goes into effect
30 days
flood disaster protection act of 1973
if a community participates in the program, flood insurance is required for grants or loans for buildings in floodplain from federal agency
what is a pre FIRM building
built before effective date of first FIRM (before studies done on area)
use subsidized rates
how are post FIRM rates determined in BFE zones
elevation of lowest floor (basement) of building in relation to BFE
if no BFE, rates based on overall loss experience and damages for buildings within that zone
floodproofed rates
building must be floodproofed 1’ above BFE to get rates for building at BFE
coastal barriers resource act 1982 (CBRA0
stops federal assistance to development in underdeveloped portion of coastal barriers
what can emergency manager do in a large disaster
open emergency operations center (EOC)
3 categories of building conditions
A - apparently safe
B - obviously substantially damaged
C - could be substantially damaged
emergency repairs that do not need permit
removing damage house contents
cleaning
covering holes to prevent further damage
making building more safe
normal moisture level
over 10 to 15%
then, wall cannot be covered by paint or wallboard
6 basic mitigation measures
prevention
property protection
natural resource protection
emergency services
structural projects
public information
10 step mitigation planning process
- organize to prepare the plan
- involve the public
- coordinate with other agencies
- assess the hazard
- assess the problem
- set goals
- review possible activities
- draft an action plan
- adopt the plan
- implement, evaluate, and revise
6 guidelines of MOM (multi objective management)
keep efforts locally based
understand the flood problem and its relation to the watershed
think broadly about possible solutions to reduce the flood problem
identify the other community concerns and goals that could have a bearing on the flood problem
obtain expert advice and assistance from gov agencies and private orgs
build partnership amound private and public ground and individuals that can be enlisted to work on the objectives
national flood insurance reform act of 1994
establish flood assistance (FMA) pays 75% of cost of mitigation measures
gives states funding for states to distribute - must have flood mitigation plan
pre disaster mitigation program
75% federal cost share
fund mitigation plans by states and communities
what is the stafford act
emergency act - presidential disaster declaration so now programs can provide mitigation assistance
3 main tyes of financial assistance
public/infrastructure assistance - provides 75% of cost of repair to public buildings / structures on top of insurance
human services programs - individual and family grants
hazard mitigation programs - pays 75% of cost of mitigation projects
small business administration disaster loan program
