Applications of HAZUS for 
Modeling PossibleLosses Avoided from Flood 
Hazards



Presenters


•Rodney Renkenberger, 
Maumee River Basin Commission (MRBC)
•Kevin Mickey 
The Polis Center




Background


•1982 –March flooding from quick snowmelt 
combined with rainfall to cause the 3rd 
worst flood of record since 1913. Over 35 
structures substantially damaged.
•1985 –March flooding similar to 1982. 
Snow accumulation was not as much as in 
1982. 35 structures were substantially 
damaged.




Background


•2003 –July flooding from 7 continuous days of 
rainfall in the St. Marys Basin. Storms tracked 
the same path each day, taxing the St. Marys 
River and causing the worst flood of record. 
Over 55 structures substantially damaged.
•2005 –January flooding resulting from frozen 
ground and continuous rainfall, caused the 4th 
worst flood of record. Many of the homes 
damaged in 2003 were substantially damaged 
again because of limited acquisition funding.




Background


•1997 –First grant application submitted for 
acquiring flood-risk properties
•MRBC applied for FMA grant to acquire the 
10 most at-risk structures
•2003 –Record “Firecracker Flood” 
presented an opportunity using HMGP funds 
to acquire the vast majority of at-risk 
structures.




Acquisition Process / Guidelines


•MRBC developed a Comprehensive Flood 
Mitigation Master Plan in 1995 to mitigate 
future flood damages in the Maumee Basin.
•MRBC Master Plan is based on non-
structural recommendations to permanently 
mitigate future flood damages.




Acquisition Process / Guidelines


•MRBC Flood Mitigation Master Plan 
guidelines recommend acquisition of the 
following: 
•Structures subject to 2’ feet or more of 
inundation;
•Structures located within the Regulatory 
Floodway;
•Structures identified as Repetitive Loss 
Structures.




Pilot Project Goals


•Answer the following questions:
–Can HAZUS consistently produce depth grids 
that are appropriate for structure specific loss 
avoidance studies?
–Can HAZUS generate loss information that is 
sufficient to perform a loss avoidance study?







At Risk Structures


•HAZUS User Defined Facility table was 
created with 62 residential structures that 
were bought out by the MRBC.
•Much of the required HAZUS input was not 
immediately available
•Examples of Assumptions
–Replacement cost calculated at 1.25 x market 
value
–FFE estimated based partially on expert opinion







Hazard Definition


•Steps
–Run a HAZUS Return Period analysis for 100 
year flood based on a 1/3 arc second DEM and 
1 square mile drainage area 
–Note: 100 year event one selected as being 
equivalent to the event that we the basis for the 
decision to buyout structures







Manningsn = 0.07 (default)

Manningsn = 0.08 (default)

Manningsn = 0.09 (default)



Hazard Definition


•Return Period Hazard Option Conclusion
–HAZUS failed to represent the inundation area 
adequately –additional runs were completed 
with modification of Manningsn value



•Enhanced Quick Look method was used to 
derive depth grid based on AE Zone from 
DFIRM




Enhanced Quick Look –AE Zone

Culvert Locations



EQL vsHigh Water Marks


A comparison of 
actual high water 
marks with HAZUS 
EQL depths 
yielded mixed 
results



EQL vsHigh Water Marks


Average 
difference was 
1.1 feet.

However, there 
were several 
differences that 
significantly 
exceeded this 
amount.



Analysis



Analysis



Analysis



Conclusions


•Be very cautious if relying on HAZUS to 
generate the flood inundation area 
especially for detailed studies of this type
–HAZUS accuracy is relative to accuracy of DEM/ 
Contour data;
–Over-land flow paths may not be depicted / 
recognized by HAZUS







Conclusions


•Conveyance structures allowing water to 
transfer into other areas may not be 
recognized;
•Local Officials, County Engineers, County 
Surveyors, and City Engineers should be 
consulted to obtain the most accurate flow 
information relative to over-land flow-paths 
that may not be depicted by HAZUS. 




Conclusions


•In addition to structural building costs and 
content losses avoided, the following losses 
should also be considered as losses 
avoided:
–Emergency Response Costs;
–Adverse impact to local infrastructure;
–Value of Open Green Space in reducing future 
flood losses;
–Social –Economic Losses







Future Plans


•Explore potential of using depth grids 
created with other H&H models.
•Develop recommendations for using HAZUS 
to support loss avoidance projects in 
Indiana.




Thanks for Coming!