Next Generation Flood Alert in
Houston
Philip B. Bedient
Civil and Environmental Eng., Rice University
Major Causes of Urban Flooding
(Excess Water that Inundates)
9 Highly Developed (urbanized) Area
9 Intensity and Duration of Severe Rainfall 9 Flat Topography with Little Storage
9 Increased drainage density and impervious cover
9
Flood Control methods attempt to replace storage with local and regional level detention pondsUrban Basin Response is Rapid
Drainage and soil type
Concrete channels
Rapid urbanization
Reservoir Divide Natural stream Urban Concrete channel 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 0: 30 1: 00 1: 30 2:00 2: 30 3: 00 3: 30 4: 00 4: 30 5: 00 5: 30 6:00 Time Ra inf a ll ( in 100 Year Storm 8.4 inches 10 Year Storm 5.6 inches 25 Year Storm 6.6 inches 5 Year Storm 4.8 inches Q tRice/TMC Area
Brays Bayou Watershed
Harris Gully Area: 4.5 sq. mi.
Brays Bayou Area: 129 sq. mi.
Problems in Predicting
Houston Hydrology
Rapidly moving weather systems - intense rainfalls Streamflows often exceed bank capacities
Severe street flooding occurs during routine rainfalls
Planning for future urban development must consider both the local and regional watershed scale
Urban developments must be better designed with internal storage due to stream capacity limitations
New CASA radars will allow for improved accuracy of rainfall estimates in small scale watersheds.
Technology has Revolutionized
the Field of Urban Hydrology
Geographical Information Systems (GIS)
Large Hydrologic and Meteorologic Databases
LIDAR data for topographic display
RADAR rainfall estimates from NEXRAD
Distributed hydrologic models that capture
data variability better than older modeling
approaches
Advanced measuring tools for severe weather and
NEXRAD Rainfall
Estimates
NEXRAD provides real-time
data every 5 minutes
Equivalent to 250 gages
in Brays Bayou watershed
Each pixel now represents an average rainfall
over 1 sq km - more accurate than gages
NEXRAD rainfall estimates compare well with
Goals of Flood ALERT System
Increase lead time for flood warning to
2-3 hrs
Provide accurate real time rainfall
estimates and images as storms approach
a critical area
Provide a method to estimate peak stream
flows at points of critical interest
Provide frequent information updates via a
dynamic web site - updates in real time
Distributed and Lumped Parameter Rainfall / Runoff
Analysis
Distributed and Lumped Parameter Rainfall / Runoff
Analysis
Bayou Camera
•Flood door closure •Evacuations
•Recall of Personnel •Backup Power
Flood
Protection & Emergency Actions Alert Level Flood Protection Action Levels •Fax •Pager •E-mail Rice/TMC
Rice/TMC Flood Alert System (FAS2) - 2003-06
NEXRAD
calibration
Current Radar
Quantitative Precipitation Forecasts
Forecast
Next Generation FAS
Inundation mapping as storms approach
- Floodplain Library
- Real-time infrastructure risk analysis
- Flood prediction for evacuation routes
Incorporation of storm surge impacts
- Coupling of inland flood alert systems with
coastal storm surge modeling
Simulated Peak Flow =12071 cfs at Time 2
Radar RF@ T2
HEC-1@ T2
Simulated Peak Flow = 17000 cfs at Time 3 Radar RF@ T3 HEC-1@ T3
Peak Flow = 33700 cfs at Time 5 Radar RF@ T5 HEC-1@ T5
• Radars were developed by Umass, weather predictions from OU, radar testing at CSU, and Rice U handling the Houston flood testbed • NetRAD system will be deployed this summer in Houston and
will expand over time as more users are identified. 5-7 radars can cover most of the affected Houston area with support from NEXRAD. • NetRAD should improve predictive accuracy at small basin scales, and the FAS2 is being improved to receive NetRAD data for Houston.
CASA - NSF ERC
Radars
will revolutionize our ability to sense severe
CASA QPE Objectives
Bring CASA radars to Houston testbed - 2006 -07
Build off existing Flood Alert System (1998 - 06)
Evaluate hydrologic and hydraulic interactions
between local and regional scale watersheds
Test updated Vflo model in Texas Medical Center
and White Oak basins
Test NEXRAD vs. NetRAD and rainfall gages for
several storm events
Expand the method and model to other areas in
NSF Proposed NETRAD Sites for Houston Testbed New Radar Technology for 2006-2008 time period Provide data at 200 m x 200 m scale pixels
Texas Medical Center
Texas Medical Center
Proposed CASA Radar1
Proposed CASA Radar1
Smith Tower Location
Center for Storm Prediction, Warning
and Evacuation
SEVERE Storms
Advanced Model Predictions
Real Time Web Site
ALERT Network Evacuation Plan Shelter in Place Emergency Centers EDUCATION OUTREACH
The Partnership Concept
The suffering from Hurricanes Katrina and Rita along the Gulf Coast clearly demonstrated the extreme and dismal situation that exists in disaster planning and management in this region.
This Partnership for Innovation will develop the necessary infrastructure to coordinate research programs at five major universities, working with the private sector, to
deliver innovative technologies in a timely manner, and to disseminate warnings to governmental agencies
responsible for at-risk communities.
The NWS cannot deliver this customized service for urban coastal areas and critical facilities
The Partnership Concept
The partnership mission:
– (1) Develop the ADCIRC Model for real time surge prediction along the coast
– (2) Link surge prediction with radar-based flood
prediction at the coast, and create inundation maps thru GIS
– (3) Apply innovative designs above to emergency transportation and evacuation
– (3) Develop disaster trained workforce /educational programs that link partners to private companies and HGAC
The Members
Rice University - (Lead) - Flood prediction, infrastructure, and societal impacts
Univ of Houston - Infrastructure risk analysis, education center outreach LSU - Hurricane & surge prediction, evacuation planning
University of Texas - surge prediction for TX, satellite data, evacuation, advanced data coordination
UT Brownsville - coastal impact community - RFT. TSU - transportation and evacuation systems
HGAC - Houston Galveston Area Council - regional COG for hurricane preparations and evacuation
TMC - Texas Medical Center - primary care and research facility City of Houston - important infrastructure and security issues VAI, Dodson, URS - private companies in this area
STORM SURGE MODEL - LSU
100yr Rainfall TSARP Modeled Floodplain
100yr Rainfall TSARP Modeled Floodplain
12 inches of Rainfall
288
More Accurate Maps of Storm Surge Linked to inland flooding needed
Currently not linked at all due to lack of Federal authority
