GIS for Faster Analysis of Dam-Break Flows
Steve PitmanGIS in Water Resources – Fall 2003
Dr. David Maidment – UT Austin
The Problem:• A breached dam releases
large volumes of water very rapidly
• Can’t predict dam-break floods using observations of natural floods
• Existing dam-break models– Complex, tricky and time
consuming– Not conducive to rapid
analysis
Dams in the U.S.• Approx. 77,000 total• Consider a worst case
scenario: On the Colorado River, Glen Canyon Dam and Hoover Dam, 370 miles apart, created Lake Powell and Lake Mead with combined storage equal to roughly four times the river’s annual flow.
USBR Photo
USBR PhotoLake Powell
What would this water do if rapidly released?
Teton Dam, Idaho – June 5, 1976Teton Dam, Idaho – present day
GIS in Dam-Break Analysis Today• Pacific Disaster Center
uses the M2M interface to translates FLDWAV output for display in ArcGIS
• NWS developing FLDWAV-GIS link for displaying flood predictions
• PBS&J (FEMA Contractor) has fielded a Watershed Analyst extension that automates pre- and post-processing of watershed modeling data
Current Dam-Break Models• DWOPER & DAMBRK developed by
National Weather Service (NWS) in 1970’s• NWS released FLDWAV in 1990’s
– Combined DWOPER & DAMBRK– Added functionality
Input:Dam
parametersValley
geometry
Output:Flow rates &
depths at selected locations
Estimate breach
characteristics•Geometry
•Formation time
Outflow Hydrograph
Flood Routing
Finite-difference solution of
dynamic wave equations
Adding Automation with GIS
Input:Dam
parametersValley
geometry
Output:Flow rates &
depths at selected locations
Estimate breach
characteristics•Geometry
•Formation time
Outflow Hydrograph
Flood Routing
Finite-difference solution of
dynamic wave equations
Geodatabase
GIS
Geospatial data Time Series data
Interface Data ModelPre-Processing Post-Processing
Example
USGS – The National Map
Resources• Applied Hydrology, Chow et al, McGraw Hill (1988)• U.S. Geological Survey websites• U.S. Bureau of Reclamation websites• National Inventory of Dams, U.S. Army Corps of
Engineers• Arc Hydro, Maidment, ESRI Press (2002)• Source of photos
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