1. Update on Hazus AAL Study and Data
Eric Berman - FEMA
Tom Schweitzer– STARR PTS

2. Contributors Tom Schweitzer Dan Deegan Shane Parson PTS – STARR
PTS – BakerAECOM
Shane Parson
PTS – RAMPP

3. Past Flood Risk Assessments: Pre-HAZUS Studies
Donnelly Data – mid 1980’s:
Ranking of communities
Use for decisions on mapping restudies
Property At Risk Data:
Refinement of Donnelly
Removed areas that would not be developed (water bodies)
Lost data from previous effort

4. Average Annualized Loss (AAL)
FEMA initiated the AAL Study in 2009 to provide a Nationwide Loss Dataset
Level 1 conducted on every county in the contiguous United States using Hazus-MH for both Riverine and Coastal analysis
Used national data sets for consistency within the analysis
Losses based on building and contents

5. Summary of Average Annualized Loss (AAL) Study
Hazus AAL Study
Completed March 2010
Used Hazus-MH MR4
Losses for 48 states and the District of Columbia
Included 3,109 counties
Calculated losses for five return periods:
10-year / 50-year / 100-year / 200-year / 500-year
Calculated average annualized losses (AAL)
AAL losses extracted from HPR files at the Census block
AAL losses complied by county, state, and watershed (HUC-8, April 2010 WBD)
Usability analysis performed
First national AAL flood loss estimation study

6. Summary of AAL Study
Hazus-MH Flood Average Annualized Loss Estimation (AAL) was performed for continental U.S.
Level 1 Analysis
Inputs:
County-wide regions
10 sq mile drainage area
30M USGS DEM
Default Census data (GBS)
Final Output included:
Return period losses
Total exposure
Average Annualized Loss
Annualized Loss Ratio
Relative Average Annualized Losses by State

7. AAL Results Total Annualized Losses Estimated at 55 Billion:
Includes both riverine and coastal
Using NFIP program average annual losses and other source of annual flood loss data, sets a lower bound of the annualized flood loss at minimum of 10 billion annually.
Relative Average Annualized Losses by State
Annualized Loss Ratio by State

8. Hazus AAL Usability Analysis
Hazus AAL Usability Analysis (Performed by the 3 FEMA PTS)
Completed 4/2011
Analyzed several aspects of Hazus flood loss hazard development and calculation and understand constraints
Analyzed Hazus procedures to see if there are factors that contributed to the high initial AAL loss number
Can any of the procedures be quantified and used to adjust the AAL loss totals?
Developed an understanding of the limitations of a level 1 Hazus analysis (10 sqmi)
Is the AAL data a usable data set for Risk MAP?

9. Hazus AAL Usability Analysis
SUMMARY
Use of 30 M DEM - some issues in developing an accurate flood hazard, (only national topography data set)
Use of the Census data is appropriate for this level of analysis (planning level)
The weighted area method for losses can overstate losses
10 sqmi drainage area - though limiting, use of smaller threshold requires significantly more resources (processing time)
Possible double counting of losses in coastal areas
Weighted area method takes the total building stock of a census block and calculates the losses based on the percent of the census block flooded. This even distribution of the building values across the census block can over state losses at times.

10. Hazus AAL Usability Analysis
SUMMARY
AAL losses were overstated with 2 and 5 year return periods losses included in the AAL calculation (removed from final AAL estimate)
AAL losses were recalculated outside of Hazus using the 5 return periods (10, 50, 100, 200, 500-year) losses
AAL losses were calculated using Log normal*
Should use only one cross-section for all return periods
Data is appropriate for use in Discovery meetings, sequencing and general comparison of relative risk between areas
* Hazus 2.1 uses a linear AAL calculation
Note that the calculation used to recalculate the AAL with out the 2 and 5 year return periods used log normal and the newest version of Hazus 2.1 uses a linear calculation. The difference in the totals is negligible. The linear calculation was used for application programming reasons.

11. Average Annualized Loss
Availability Data & Format
Shapefile format
Access Database
Data available by census block (2000 Census)
Data available by watershed (HUC)
Certain data requires HQ approval

12. GIS Format Intended Uses: Identify flood prone areas and
Communicate relative flood risk (building and content losses)
Though there is specific dollar loss data with each Census block the data should only be used to represent and compare the relative losses within a community, watershed, county or state. This is because the AAL data was derived using course national data sets.

13. Use of AAL Values
Loss values need to be shown as relative rather than absolute dollar amounts.
Proper use of the AAL loss data. Notice relative scale used to represent the AAL data for comparison.

14. Discovery Meeting Discovery Map
The AAL is appropriate for use on discovery maps to portray the location of various flood risk. (red pixeled area)

15. Current AAL Data Availability
Annualized Losses by Census Block (2000 Census)
Availability Data & Format
Can be used to satisfy Discovery meeting requirements
Certain data requires HQ approval

16. Flood Risk Assessment Purpose and Intended Uses
Identify Areas and Communicate Relative Flood Risk:
Flood prone areas
Vulnerable people and property
Provide Flood Risk $:
Potential damage severity for different flood frequencies
Identify locations with possible cost effective mitigation options
Improve Estimates for Flood Risk $:
Losses from Average Annualized Loss (AAL) Study
Refined losses from new flood study depth grids
Refined general building stock data from local sources

17. AAL Data Requirements – Appendix O
Appendix O for Risk MAP
Requires other data from the Hazus AAL data set
Certain data requires HQ approval

18. AAL Data Requirements – Appendix O
AAL Access table only provides annualize loss data for:
Total Loss
Building Loss – Total
Contents Loss – Total
L_RA_AAL requires the following to be extracted from AAL Study.HPR (Hazus) files:
Data for all 5 individual return periods
More detailed loss data fields (such as total, building, and contents losses divided into residential, commercial, and other)
Certain data requires HQ approval

19. Flood Risk Data
AAL data has been compiled into a single database for use in extracting the required data in Appendix O format
We have develop a tool that performs this extraction into MS Access Databases
This is the initial assessment data that is required to populate the Risk Database for use in producing Risk MAP non-regulatory products
The new Risk MAP products require data from Hazus to populate the Risk MAP Database

20. Flood Risk Data
We have develop an application that allow you to extract the data from the AAL results database
Select your state and then county
The application will then extract the fields and data required to populate the Risk Map Database
This data canthen be imported into your Risk Map database
Currently we are finalizing the data. It can be requested from the PTS contractor for your Region.

21. Flood Risk Assessment Delivered
What are these Products? This will include the 1% (100-yr) composite results shown on the Flood Risk Map and community-specific summaries in the Report. 21

22. Flood Risk Map Elements
On the Flood Risk Map, the 1% or 100-yr composite results are shown, along with symbology showing where new studies have been done.

23. Flood Risk Report Elements
Here is a zoom-in of one of these tables in the report.

24. Moving Forward
The process for compiling the new data into a national data sets has not yet been determined
Additionally the process to stored and distributed this data nationally as yet been determined
Currently we are looking at storing the data associated with Flood Risk Databases in the MIP until other means can be developed to house the information.
The existing extracted AAL does not match the Risk MAP non-regulatory risk database