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Lessons Learned: Risk MAP Early Demonstration Project Madison County, AL

TN AFPM 2011Montgomery Bell State ParkJuly 28, 2011

Eric Zgonina, EITAMEC

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Presentation Outline

Map Modernization & Risk MAP Overview Risk MAP Early Demonstration Purpose Study Area Selection/Proposal Product Results and Findings Stakeholder Feedback Mapping Partner Recommendations Moving forward with Risk MAP

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FEMA Map Modernization Program

Map Mod brought NFIP mapping into 21st century

Ran from 2003-2010 Transition from paper to digital

format Significant advantages in capability

and precision

New digital SFHA’s for 92% of the population

Encourage use of quality local data

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FEMA Vision for Risk MAP

FEMA Risk Mapping, Assessment, and Planning (MAP) Program Deliver quality flood data that increases

public awareness Initiate mitigation measures to reduce risk

and loss of life and property Transform traditional flood mapping to

better integrate:– Identification– Assessment– Communication– Planning for– Mitigation of flood related risks

Ensure 80% of the Nation’s flood hazards are current

Update flood hazard data for 100% of the populated coastal areas in the Nation

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Risk MAP Early Demonstration Purpose

Early Demonstration ProjectsValidate Risk MAP products increase

value to program visionEmphasize production efficiencies

and innovationsUpdate GuidanceAscertain product refinementDetermine costsStakeholder feedback

Risk MAP Development

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Early Demonstration Requirements

Project study area funded prior to 2010, pre-appeal phase

Strong Regional Support Efforts could not exceed $100k Good elevation data Completion by February 2011,

lessons learned integrated prior to FY2011 Risk MAP

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Early Demonstration Area Selection, Madison County, AL

Madison County Project Effective 1998 FY2008/2009 funding Strong stakeholder relationship,

OWR and AMEC Current ground surface data:

LiDAR 2007 Area which will benefit from

products, mitigation potential Existing county revision, several

detailed studies

Produce: Changes Since Last FIRM Flood Risk Probability Grids Depth Grids Flood Risk Report Flood Risk Map Two Stakeholder Meetings

Enhanced: Annualized Loss Estimates Velocity Grids Areas of Mitigation Interest

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Changes Since Last FIRM

ESRI model builder tool developed Data stored in Flood Risk Database FRR shows summaries SFHAs

affected Greatest level of effort:

attributing factors contributing to the shape of the SFHA

Population and buildings affected

CSLF example: Bradford Creek, Madison, AL

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Areas of Mitigation Interest

Significant proposed and recent

development

Urbanization

Undersized culverts

Floodplain pinch points

Channel Improvements

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Areas of Mitigation Interest

Flood Control Structures

Risk “hot spot” areas

Home buyouts

Previous claims

Locations of

successful mitigation projects

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Water Surface Elevation and Flood Depth Grid

By products of floodplain mapping

Mosaicing rasters can horizontally skew data

Resampling model grids can reduce the magnitude of the skew Resulted in average horizontal

skew of less than one foot

Initial Raster Mosaicing

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Velocity Grid Methodologies

HEC-GeoRAS and RAS Mapper methodologies were considered HEC-GeoRAS - smoothest and most accurate velocity grid

Floodplain polygons required inputs for velocity grid creation AFG chosen over HEC-GeoRAS

Using AFG Floodplain Using Geo-RAS Floodplain

Tiling

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Velocity Grid Results

Velocity grid example: confluence of Indian Creek Trib 1 and Indian Creek, Intersection

of Slaughter Road and Interstate 565 Huntsville, AL, 100 yr event

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Percent Chance of Flooding Equations

lowerupper

lowerannualupperannual

WSEWSEpp

1010 loglog

ationGroundElevp upperannual 10log

annualp10log

10annualp

Ground Elevation (WSEL – Depth Grid)

% AnnualChance

(Log)

(Lin

ear)

30 -Year Percent Chance

1 - (1 - p)30

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Percent Chance of Flooding Methodology

Procedure derived based on FEMA guidance ESRI model builder tool created Grids were created for each of the selected flooding source intervals

and mosaiced by county

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Percent Annual Chance and Percent 30-Year Results

Aldridge Creek, near Valley Hill Country Club area, Huntsville, AL

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Flood Risk Assessment

Flood Risk Assessment Products (10%, 4%, 2%, 1%, 0.2%, and annual chance)

Area (Risk, Very Low to Very High) Classification (Residential,

Commercial, Other) Population Average Value (buildings/census

block) Total Loss Building Loss Content Loss

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Result Discrepancies

High density

in floodplain,

LOW RISK?

Undeveloped areas,

high risk?

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Locally Supplied Building Data

Building footprints First floor elevations Constructions materials Number of stories or height Year built/age/building quality Building value

Content value Building type Latitude/Longitude Occupancy class

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Flood Risk Assessment Results

FEMA provided a Level 1 HAZUS risk assessment for each census block.

Results were poor in quality. Classified all census blocks as residential in Madison County. Community stakeholders noted areas of high risk labeled as very low

risk in HAZUS. Enhanced flood risk assessment not possible with current version of

HAZUS, needs to be revised. Estimated Potential Losses for Flood Event Scenarios

Total Inventory 10% (10-yr) 2% (50-yr) 1% (100-yr) 0.2% (500-yr) Annualized ($/yr)

Estimated ValuePercent of Total Dollar Losses

Loss Ratio Dollar Losses

Loss Ratio Dollar Losses

Loss Ratio Dollar Losses

Loss Ratio Dollar Losses

Loss Ratio

Residential Building/Contents $30,093,892,200 n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a

Commercial Building/Contents $7,409,054,950 n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a

Other Building/Contents $4,663,139,042 n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a

Total Building/Contents $42,166,086,192 100% $396,750,000 1% $523,033,000 1% $579,867,000 1% $701,102,000 2% $47,067,000 <1%

Business Disruption n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a

TOTAL $42,166,086,192 100% $396,750,000 1% $523,033,000 1% $579,867,000 1% $701,102,000 2% $47,067,000 <1%

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Watershed Flood Risk Report

Provides a summary of all flood risk information in single source.

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Flood Risk Map

Countywide base data FEMA AAL Contributing Engineering Factors Areas of Mitigation Interest

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Community Feedback - CSLF

Integration• Easily incorporated

Improvement• No large potential

Community Benefit• Could help relate flood risk to public

Concerns• Public could blame community leaders for changes

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Community Feedback – Analysis Grids

Integration• Not easily integrated into daily routines

Improvement• No large potential

Community Benefit• Help identify trouble areas

Concerns• Unable to determine BFE’s in lieu of FIRMs

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Community Feedback – Flood Risk Assessment

Integration• Neutral

Improvement• Community specific data incorporated

Community Benefit• General information purposes only

Concerns• Accuracy

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Community Feedback – Areas of Mitigation Interest

Integration• Areas already known by community

Improvement• Dependent upon community participation

Community Benefit• Minimal

Concerns• Liability

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Community Feedback – FRR/FRM

Integration• General information purposes only

Improvement• May be difficult to use in paper format

Community Benefit• Not helpful

Concerns• Funding towards more detailed studies

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Mapping Partner Recommendations

•More detailed guidance•Start and end of flooding source effects procedure•Additional data field for inconsistent flooding source

CSLF

•Specified naming convention and cell sizes for all grid products

•Guidance for mosaicing rastersFlood Depth and Analysis Grids

•New version of HAZUS needed•Account for incomplete community datasetsFlood Risk

Assessment

•Language and graphic recommendations•Map format recommendations

FRR/FRM

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Revised FEMA Guidance, Appendix N & O

CSLF Contributing engineering factor

became a variable attributed with 12 possible fields

Ex: New Terrain Data- If new terrain data was introduced and that new data caused the floodplain boundaries to change, the attribute would be “True”

No procedure for start/end of flooding sources included.

No new field for new flood source added

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Revised FEMA Guidance, Appendix N & O

Flood Depth Analysis Grids

Defined naming convention and raster cell size (resolution) for all raster datasets =10 meters (32.808 feet).

If higher resolution depth or analysis rasters are produced, Mapping Partners shall submit outside of the FRD.

Section detailing combining depth grids at a confluence, acceptable depth difference (+/- 0.5 ft), engineering judgment applied when exceeds

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Revised FEMA Guidance, Appendix N & O

Flood Risk Assessment Guidance details MR4 version cannot calculate annualized loss but

does include a HAZUS alternative loss calculation formula. Guidance does not address partial dataset information entered into

the Comprehensive Data Management System (CDMS) but defers users to CDMS manual.

MR5 available and new version of CDMS should be available soon

AOMI’s Remains point feature Defines how to create AOMI Data including detailing the data mining

process

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Revised FEMA Guidance, Appendix N & O

FRR Guidelines are not mandatory

and some portions may be tailored by writer

Template Tables may be edited based on available information

Template text edited

FRM Purpose of FRM is intended for

facilitation purposes to involve communities

Legend modified- specifies AOMIs

Most recommendations followed

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Moving Forward with Risk MAP

Community

Other Parties

Mapping Partner

FEMACommunication

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Mutually Beneficial Partnerships

Develop a framework that collects information on the effectiveness of partnerships

Ensure Risk MAP products from partnerships are complementary and not duplicative

Collaborate with partners to improve understanding and encourage action

Provide support to partners to include policies, procedures, guidelines, and training

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Outreach and Communications

Flood Insurance

Policy HoldersGeneral Public Planners

Engineers Surveyors Environmental Groups

Realtors, Homebuilders

Insurance Agents Lenders

State and local representatives

Other Federal Agencies

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Outreach and Communications

Reaching Stakeholders Conferences Media Relations Community Meetings Social Media

Facebook Twitter

Web Applications Phone apps

Other

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Presentation Conclusions

Risk MAP Early Demonstration Project was successful Emphasized production efficiencies and innovationsPresented product cost estimatesProvided Stakeholder feedbackProvided Mapping Partner feedbackAided in update to guidance