fema’s flood risk review meeting: building confidence in risk map products 2012 asfpm national...

FEMA’s Flood Risk Review Meeting: Building Confidence in Risk MAP Products

2012 ASFPM National ConferenceSan Antonio, Texas

May 24, 2012 2:00 pm

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Presentation Outline Risk MAP Overview

Risk MAP and Flood Risk Review

Case Study: Butler County, Ohio Flood Risk Review Meeting

Conclusions & Recommendations

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Risk MAP Overview Risk Mapping Assessment & Planning (MAP)

• Mapping – Flood Hazard and Risk Identification• Assessment – HAZUS and other Risk Assessment tools• Planning – Hazard Mitigation Plans

Risk MAP Mission• Conducted at watershed level• Deliver quality data• Communicate more effectively about flood risk to citizens• Inspire mitigation actions that reduce risk

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The Risk MAP Overview

Risk MAP Program Objectives

Through collaboration with State, Local, and Tribal entities, Risk MAP will

deliver quality data that increases public awareness and leads to action

that reduces risk to life and property.

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Risk MAP Overview and Flood Risk Review Quality Data

• Flood Risk Review is to assure additional collaboration occurs• Result is better data that is supported by stakeholders

Public Awareness • Flood Risk Review is to assure stakeholders understand the data, datasets, and

products• Understanding promotes better awareness

Action that Reduces Risk• Flood Risk Review is to discuss how stakeholders can use data and information to

promote risk reduction• Communicate the technical aspects of data development and output for future use

in risk reduction actions

Quality Data Public Awareness Action that Reduces Risk

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Risk MAP Overview and Flood Risk Review

Added new products

Added new datasets

Added new meetings • Flood Risk

Review

Flood Risk Database

Flood Risk Map Flood Risk Report

Ad-Hoc & User-Defined Flood Risk Analysis and Mapping

Flood Depth & Analysis Grids

Flood Risk Assessment Data

Areas of Mitigation Interest

Changes Since Last FIRM

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Risk MAP Timeline R

isk

MA

P3

- 5

years

GD E• FBA

Resilience Meeting Review

Potential actions to incorporate into mitigation plans

Preliminary FIRM Issuance

FIRM Effective

Consultation Coordination Officer (CCO) Meeting/ Open House

Items Presented: FIRM (Regulatory) Final Risk MAP Products

(Flood Risk Map, Report, & Data Sets)

Optional Flood Risk Review Meeting

Items Presented: Risk MAP Products (Flood Risk

Map, Report, & Data Sets)

Discovery Meeting

Items Presented: Updated

Discovery Map Draft Project

Plan Draft Project

Charter

C F

Changes Since Last Map & Impacts

Planning Execution

A. Planning & Budgeting (3 Mos.)

B. Discovery (2-4 Mos.)

C. Data Development & Sharing (9-15

Mos.)

D. Risk Awareness & Mitigation Outreach (1-3 Mos.)

E. Proposed NFIP Map Changes & Impacts (1-3 Mos.)

F. Preliminary NFIP Map Release & Mitigation Planning (1-3 Mos.)

G. Due Process & Path Forward (9-15 Mos.)

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Flood Risk Review Meeting Meeting Objectives

• Quality Data• Public Awareness• Action that Reduces Risk


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Flood Risk Review Meeting – Quality Data History of floodplain mapping and previous

projects Present Risk MAP products to technical

stakeholders• Discuss input and output engineering data• Illustrate best available and most recent data• Confirm whether information is accurate• Obtain additional information about new study areas


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Flood Risk Review Meeting – Public Awareness Non-regulatory products and datasets Review and discuss the mapping project data

development methods and workmaps• Engineering assumptions

Involve stakeholders to spread message• State NFIP Coordinator and SHMO• Federal and State Agencies• Local Community Officials, FPAs, Planners, EMA Officials, etc

Additional Collaboration


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Flood Risk Review Meeting – Action that Reduces Risk Communicating non-regulatory products and

datasets Using non-regulatory products and datasets

• Using Risk MAP provided information to enhance local data and vice versa

Products used for making decisions to reduce flood risk

Benefits of and resources for local communication about risk to residents


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Butler County, OH Meeting Topics History of floodplain mapping in area

Physical Map Revisions (PMRs) and levees

Data development

Non-regulatory products and datasets

Use of non-regulatory products

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Butler County – Quality Data History of Flood Studies

• Original studies performed in 1980’s and early 1990’s• Map Modernization project created digital countywide product and

incorporated new studies and LOMR’s for several streams Effective in 2010

• “Natural Hazard Mitigation Plan” developed in 2011 by County EMA

• Several communities had long-standing concerns about the accuracy of the floodplain mapping


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Butler County – Quality Data Physical Map Revision Project (PMR) developed data for a

mapping update:• Scoping Meeting held on December 21, 2009• 100 miles of updated detailed studies • 11 miles of new limited detailed studies• 31 miles of updated approximate studies – replaces all effective Zone A’s• FIS report and 93 FIRM panel revisions

Levee Mapping in Hamilton and Middletown• Levee accreditation process is pending


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Butler County – Quality Data Hydrology - Previous studies

• Mostly ODNR regression equations (Bulletins No. 32, 43 and 45)• HEC-1 Rainfall/Runoff Model

East Fork Mill Creek, Gregory Creek, Millers Creek, Shaker Creek

• Gage Analysis Great Miami River – 67 years of record

Hydrology - New studies• USGS Regression equations from 2006• HEC-HMS Rainfall/Runoff Model

Considers land use and regional detention facilities in analysis Bull Run/Collins Creek, East Branch Pleasant Run, East Fork Mill Creek, Four Mile Creek, Gregory Creek,

High School Tributary, Mill Creek, Millers Creek, Shaker Creek, Tributary to East Fork Mill Creek, Tributary to Pleasant Run Branch No. 4, Two Mile Creek

• Gage Analysis Great Miami River – 86 years of record


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Butler County – Quality Data Hydraulics - Previous studies

• Mostly HEC-2 hydraulic model software• Field survey data from the time of study

Hydraulics - New studies• All studies used HEC-RAS hydraulic model software

Unsteady Flow modeling for Millers and Shaker Creek

• Stream channel and floodplain geometry from field survey data and 2008 OGRIP data – 2.5 foot DEM (4-foot contours)

• New Water Surface Elevation profiles calculated Detailed and Limited Detailed Studies published in FIS Approximate studies profiles viewable in HEC-RAS format

• New Floodway Analyses - Detailed Studies only• Incorporated existing bridges and culverts• Floodplains delineated using up-to-date topographic data – 2008 OGRIP


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Butler County – Public Awareness Review of the Flood Risk Dataset and Products

Flood Risk Datasets• Changes Since Last FIRM (CSLF)• Depth Grids• Study Data

Flood Risk Products• Flood Risk Database• Flood Risk Report• Flood Risk Map

Flood Risk MapFlood RiskDatabase

Flood Risk Report

CSLF Depth Grid


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Depth Grids

Butler County – Public Awareness


Show flood inundation as a function of an event’s magnitude or severity

Show that flood risk varies within the floodplain

Demonstrate the risks associated with different flood depths.

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Changes Since Last FIRM


Identify areas and types of flood zone change:

• Compares current effective (previous) with proposed (new) flood hazard mapping. (all inputs must be digital)

• Flood zone changes are categorized and quantified

Offers transparency and answers to:• Where have my flood hazards increased

or decreased?• Why have my flood hazards increased or

decreased?• Which communities are subject to new

base flood elevations (BFEs) or ordinance adjustments?

Provide study/reach level rationale for changes including:

• Methodology and assumptions• Changes of model inputs or parameters

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Contributing Engineering Factors (CEF)



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Butler County – Action that Reduces Risk Discussion of

Communicating Risk• Benefits of sharing flood risk

information• Other Resources• Emphasized using the data

to communicate risk and impact mitigation, not just evaluate insurance

Community Awareness

CSLF

New Study Data

Flood Risk

Products

Citizen engagement, community

commitment, and mitigation action

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Butler County – Action that Reduces Risk

From the 2011 Butler County “Natural Hazard Mitigation Plan”• Action Items: “Develop accurate flood insurance maps for the county” and “Inform

insurance agents and public of the National Flood Insurance Program and FEMA floodplain regulations.”

Helps identify where households and businesses are affected by map changes• Targeted Outreach• Raise Risk Awareness

Helps Local Officials explain Map Changes• Contributing Engineering Factors• Visually, Areas of Change are easily recognized


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Butler County – Action that Reduces Risk

From the 2011 Butler County “Natural Hazard Mitigation Plan”• Action Item: “Identify and inventory all structures that are subject to flood damage,

including critical facilities and repetitive loss properties and prepare feasibility studies pertaining to potential future projects to alleviate issues.”

Risk is not uniform and varies by location Use Grids to identify areas most at risk from severe flooding

• FIRMs show extent of flooding• Grids identify areas of highest flood risk• Serve as pre-screening criteria for mitigation• Identify areas to prioritize mitigation projects

Depth of flooding over roadways


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Opportunities for Future Meetings Encourage Active Participation by

Stakeholders Multiple Breakout Sessions instead of 1 at the

end Survey Forms or Worksheets

Maintain Focus on Risk – not just Flood Insurance implications of the new technical data

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Successes Stakeholders were interested in the

technical / engineering focus

Tying the Flood Risk Products to the County Mitigation Plan was well-received

Flood Risk Products for use in Emergency Mgmt was well-received

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Mike Hanke – FEMA Region [email protected]

Nathan Beach, PE, CFM – [email protected]

questions and answers

mailto:[email protected]

fema’s flood risk review meeting: building confidence in risk map products 2012 asfpm national...

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