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Flood Mitigation ProgramProtecting Lives, Protecting Property |
Floodplain Management, Mapping, and
Mitigationwww.dnr.sc.gov/flood
FLOOD RISK: CAN ANYONE FLOOD?
Maria Cox Lamm, CFMState Coordinator
February 22, 2014
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The Flood Mitigation Program and the NFIP
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rating
Mitigation
National Flood Insurance Program: Tying it all together
The NFIP balances three related areas that support each other. •
Floodplain mapping• Floodplain Management• Flood Insurance.
Mitigation also plays a huge role in the NFIP
SCDNR Flood Mitigation Program follows this comprehensive
approach to the NFIP. This results in the program being able to
assist communities with compliance issues, understanding
regulations, mapping, grant programs and impacts to insurance
ratings.
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SC Flood Mitigation Program
• 235 communities participate in the NFIP (90%)
• SC has over 200,000 policies (6th in nation)
• Issued 12 studies preliminary since Oct 2015
• Accurate, up-to-date flood hazard information is crucial to
protect lives and property
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Policy Concentration
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Floodplain Management
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Floodplain Management
A program that has federal regulations that are adopted and
enforced at the local level by ordinance.
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Regulations
To be a participating member of the NFIP a community agrees to
adopt and ENFORCE a Flood Damage Prevention Ordinance.
The ordinance must meet the minimum NFIP regulations outlined in
the Code of Federal Regulations.
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Higher Standards
Communities may adopt and enforce Higher Regulatory Standards.•
Freeboard• Cumulative substantial
damage/Substantial Improvement• No building in the Floodway
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Mapping
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Map Status
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Study Process Overview
4 - 6 years
Discovery
Base Map Selection
DFIRM Production
Hydrology & Hydraulic Studies
PDCCMeeting
FIS Report Preparation
Preliminary Map/Report Production Phase
(Typically 24-30 months)
Post Preliminary Processing
(Typically 20 months))
(Typically 8 months))
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Post-Preliminary Process
1.0PreliminaryFIS/FIRM
1 3 4 6 7 8 9 10 11 12
OCT DEC JAN APR MAY JUN JUL AUG SEPX
MAR
2 5
NOV FEB
2.0PreliminaryDFIRMCommunityCoordinationMeeting(PDCC)
1 3 4 6 7 8 9 10 11 12
OCT DEC JAN APR MAY JUN JUL AUG SEP
2 5
NOV FEB
MAR
3.0AppealsPeriod
4.0 Letter ofFinalDetermination(LFD)
5.0 CompliancePeriod
6.0EffectiveFIS/FIRMDistribution
Compliance Period
LFDAppeals Period
PDCC
Effective FIS/FIRMDistribution
06/17 11/17 12/1804/18 06/19
Preliminary
Actual time frames may vary FIS: Flood Insurance
StudyDFIRM/FIRM: Digital/Flood Insurance Rate Map
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Types of Flooding
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Columbia to the Coast
• Smooth, sandy channel• Sandy with silt and clay soils• Wide
flat floodplains
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Wide spread flooding
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Deep water
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Deep water
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Water still up days later
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Side Effects
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High water
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High water
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Columbia through the Upstate
• Shallow, rocky channel • Hilly with thin clay soils• Can have
Cliff-like channels • Typically narrow floodplains contained in
or near channel
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Off Foundation
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High Velocity: Debris
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Mud in houses
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Structural Damage
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Structural Damage
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Things out of place
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Human Impact: Belongings
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Relaying True Flood Risk
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Beyond Traditional Flood Maps
• Changing our message from in or out of the regulatory
floodplain to Low, Moderate or High Risk
• Create Flood Risk Products that assist in relaying True Flood
Risk
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True Flood Risk
Determine your flood risk. Everyone has a risk.
Low Risk• Zone X (Unshaded)
Moderate Risk• Zone X (Shaded)• 0.2 % Annual
Chance flooding
High Risk• Special Flood Hazard
Area (SFHA)• Zone A, AE, AH, AO,
or VE
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Risk MAP Products
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Depth Grids
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Velocity Grids
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Response and Recovery
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Response & Recovery
• In 2016, produced inundation information and peak arrival time
estimates
• Provided specialized information for officers in the field
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Response & Recovery
• Officers shared info from the field to verify inundation
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Drone Ortho Overlay
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Response & Recovery
– SCDOT – use to assist in determining what roads to close and
for how long
– SCDNR Wildlife and Freshwater Fisheries – used to assist in
determining where to close hunting season
– Local Floodplain Managers – used to assist in evacuations–
SCDHEC – used Drone information from Nichols
• Word got out
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Response & Recovery
Recovery will move slower in other areas
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Response & Recovery
Really slow in some areas
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Faster in others
Response & Recovery
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Lessons Learned
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Lessons Learned • People don’t always read or understand
information provided to them– Communication/Outreach/Education
imperative
• Verify data – if something doesn’t look right, investigate
• Decision Makers need tools that easily convey and advance an
understanding of flooding
• Officials requested a more dynamic, visual, and interactive
flood model for use during disasters
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Path Toward Resilience
• Dedicated website– Platform to display digital data– Develop
SC specific database– Flood warning system– Downloadable data and
models
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Path Toward Resilience• Flood warning system
– Statewide, seamless system
– Real-time mapping– State-of-the art tools
and approach– Integrate riverine and
coastal hazards– Holistic approach– Plan, Prepare,
Respond, and Recover
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Flood Mitigation ProgramProtecting Lives, Protecting Property |
Floodplain Management, Mapping, and
Mitigationwww.dnr.sc.gov/flood
QUESTIONS&COMMENTS
Flood Risk: Can anyone Flood?The Flood Mitigation Program and
the NFIPSlide Number 3SC Flood Mitigation ProgramPolicy
ConcentrationFloodplain ManagementFloodplain
ManagementRegulationsHigher StandardsMappingMap StatusStudy Process
OverviewPost-Preliminary ProcessTypes of FloodingColumbia to the
CoastWide spread floodingDeep waterDeep waterWater still up days
laterSide EffectsHigh waterHigh waterColumbia through the
UpstateOff FoundationHigh Velocity: DebrisMud in housesStructural
DamageStructural DamageThings out of placeHuman Impact:
BelongingsRelaying True Flood RiskBeyond Traditional Flood MapsTrue
Flood RiskRisk MAP ProductsDepth GridsVelocity GridsResponse and
RecoveryResponse & RecoveryResponse & RecoverySlide Number
42Response & RecoveryResponse & RecoveryResponse &
RecoveryResponse & RecoveryLessons LearnedLessons Learned Path
Toward ResiliencePath Toward ResilienceSlide Number 53
