A GIS-Based Flood Inundation Mapping and Analysis Pilot Project

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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
• Whats Next

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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

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Collaborative effort

• Silver Jackets A Natural Hazard Mitigation Team
• City of Indianapolis
• IMAGIS
• Indianapolis Museum of ART
• INDHS
• USACE
• IDNR
• NWS
• USGS
• Polis

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Observed and Predicted Flood-Inundation Mapping
and HAZUS-MH Analysis Using the Ravenswood Area
of Indianapolis as a Pilot Study
Study Area
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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

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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

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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

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Data Flow
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• USGS provides real-time river stage and
  streamflow from streamgages
• NWS uses streamgage data and sophisticated
  computer models to generate forecasts of
  stage/streamflow

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NWS data

• Flow and water-surface elevation forecasts are
  generated by the NWS River Forecast Centers
• Forecasts are based on regional rainfall-runoff
  relations
• Automated program will download the forecast data
  (XML) through the NWS Advanced Hydrologic
  Prediction Service

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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

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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

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Methodology
Earthquake Flood Hurricane
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Damage Functions
Over 800 curves and you can create your own as
well!

• Damage curves are assigned to each building
  specific occupancy class and each facility

Curves vary by hazard. This example represents a
flood hazard.
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Levels of Analysis
Level 3
Input
data hazard
specific
Required User Effort and Sophistication
Combinations
Level 2
of local and
default hazard,
building, and damage data
Default hazard, inventory,
Level 1
and damage information
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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

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FEMA Presentation August 2007
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User Defined Depth Grid

• Assign the depth grid, along with
• All analysis output options are available.

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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

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Data Flow
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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

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Whats Next?
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Summary

• Products will come with disclaimers and error
  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

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Questions?

• Contact Information
• John Buechler jobuechl_at_iupui.edu
• Moon Kim mkim_at_usgs.gov