Transcript Flood Loss Estimation

A GIS-Based Flood
Inundation Mapping and
Analysis Pilot Project
Indiana GIS Conference
February 19-20, 2008
John Buechler, The Polis Center
Moon Kim, USGS-WSC
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Presentation Outline
• Introduction
• Pilot Study Overview
• Near Real Time Analysis
• Damage Assessment
• GIS Visualization
• What’s Next
Flood-Inundation Mapping Pilot
Project
• Generate current and forecast flood-
inundation maps: USGS and NWS data
• Generate maps for import to HAZUS-MH
• Serve maps visually through Web
Collaborative effort
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Silver Jackets: A Natural Hazard Mitigation Team
City of Indianapolis
IMAGIS
Indianapolis Museum of ART
INDHS
USACE
IDNR
NWS
USGS
Polis
Observed and Predicted Flood-Inundation Mapping and HAZUS-MH
Analysis Using the Ravenswood Area of Indianapolis as a Pilot Study
Study Area
Why Ravenswood?
• Ravenswood floods frequently and often
damage is incurred
• IMA Virginia B. Fairbanks Art and Nature
Park in is partially situated in the flood
plain: occasional flooding
• Availability of high-resolution digital
elevation data, detailed building inventory
data, USGS/NWS data and extensive
historic high-water mark and flood
elevation data
Approach
• Compile GIS and HAZUS-MH datasets
• Calibrate, verify and implement hydraulic
model “FastMECH”
• Automate data retrieval from USGS/NWS
and create input files for FastMECH
• Generate a flood grid for a simulated
flood and perform a HAZUS-MH analysis
• Install, test, and implement web and map
servers
Data needs
• FastMECH
– Observed and predicted stream-flow and
water-surface elevation data (USGS, NWS)
– High-resolution digital elevation data
• HAZUS-MH
– Observed and predicted flood-inundation maps
from FastMECH
– Default hazard, inventory and damage
information for level 1 analysis and more
detailed local information for the level 2 and 3
analyses
Data Flow
• USGS provides real-time river stage and
streamflow from streamgages
• NWS uses streamgage data and
sophisticated computer models to generate
forecasts of stage/streamflow
NWS data
• Flow and water-surface elevation forecasts
are generated by the NWS River Forecast
Centers
• Forecasts are based on regional rainfallrunoff relations
• Automated program will download the
forecast data (XML) through the NWS
Advanced Hydrologic Prediction Service
FastMECH
• Two-dimensional hydraulic flow model
• Allows simulation of long reaches
• Can handle flow regime changes
• Output: Water surface (depths), water
velocity, flood arrival times
What is HAZUS-MH?
• FEMA created tool that helps communities
reduce loss to property and life that may
result from natural disasters.
• ArcGIS 9.2 extension. Requires installation
of Spatial Analyst 9.x (for flood modeling)
• Available from FEMA free of charge
Methodology
Earthquake
Flood
Hurricane
Damage Functions
Over 800 curves – and you can
create your own as well!
• Damage curves are assigned to each
100%
50%
Curves vary by
hazard. This
example represents
a flood hazard.
0%
Damage as
% of replacement cost
building specific occupancy class and each
facility
0 ft
5 ft
10 ft
15 ft
Depth of water
1 - 18
Levels of Analysis
Level 3
Level 2
Level 1
Input
data hazard
specific
Combinations
of local and
default hazard,
building, and damage data
Default hazard, inventory,
and damage information
Required
User Effort and
Sophistication
User Defined Flood Depth Grid
• HAZUS-MH allows users to
point to one or more
existing flood depth grids.
• USGS provided web-based
delivery of GIS maps and
downloadable flood grids
for HAZUS-MH analysis
FEMA Presentation – August 2007
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User Defined Depth Grid
• Assign the
depth grid,
along with
• All analysis
output options
are available.
HAZUS-MH Ravenswood Analysis
• USGS provided web-based delivery of GIS
maps and downloadable flood grids for
HAZUS-MH analysis
• HAZUS-MH, a mitigation tool, could then
also be used as a response and recovery
tool
Data Flow
Products
• Web-based near-real-time flood-
inundation maps updated hourly.
• Web-based forecast maps updated every
6 hrs per NWS
• Downloadable flood grids for HAZUS-MH
• Results from the HAZUS-MH analysis
• USGS Report
• Evaluation of models/techniques
What’s Next?
Summary
• Products will come with disclaimers and error
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estimates
Highly expandable on a geographic basis
Many possibilities for future enhancements e.g.
depth/velocity data for damage estimates
Expands HAZUS-MH from a mitigation-only to a
response tool
Web and map server maintenance may be
transferred to NWS and/or FEMA
Questions?
• Contact Information
– John Buechler: [email protected]
– Moon Kim: [email protected]