Hurricane Dolly 2008: Investigating the Potential Need for More Effective Hurricane

Data, Education, and Awareness in South Texas

Jude A. Benavides, Ph.D.University of Texas, Brownsville

Study Area: Brownsville, Texas

• City of ~160,000 people – Pop (1990): 97,000– Pop (2000): 139,000– Pop (2008): 175,000

• “On the Border / By the Sea”

Study Area: Brownsville, Texas

• Lower Rio Grande Valley (LRGV)– Population (2005): 1.15

Million– Population (2020 est): 1.78

Million• Largest and fastest growing

region in Texas without Interstate Highway service– 4th fastest growing region in

the nation 1990-2004• Including Matamoros and

Reynosa, Mexico– Pop (2005): 1.8 Million– Pop (2020): ~ 2.7 Million

The Rio Grande Watershed and the LRGV

Three primary flood risks (Brownsville area)

• Localized flooding due to intense rainfalls over area (both frontal and tropical)– Flat slopes– Rapid / Semi-regulated

Growth– Deteriorating 1o and 2o

drainage systems• Storm surge due to tropical

activity– Recent and growing concern

• Out-of-bank flooding from the Rio Grande– A growing threat due to:

• Aging levees• Rapid development in

Northeastern Mexico

Arroyo Colorado

Brownsville Resacas andShip Channel Drainage

Rio Grande Watershed

Hurricane Emily – 2005 Track (stormpulse.com)

Hurricane Dolly – 2008 Track (stormpulse.com)

Hurricane Emily (2005)

(different rainfall scale)

Hurricane Dolly 2008Category 2

Hurricane Emily 2005Category 3

Three Years – Two Near Hits!!!

Unadjusted Rainfall Totals from “Storm Total” Radar Product

• “Near miss” or “Near hit”

• Path of Hurricane Dolly takes a step northward just prior to landfall

Credit: NOAA Environmental Visualization ProgramNote: Images processed by Mr. Anthony Reisinger – UTB/TSC Environmental ScienceStudent Interning with NOAA this summer!

Hurricane Dolly – Category 1 – 9 AM July 23rd, 2008

Credit: NOAA Environmental Visualization ProgramNote: Images processed by Mr. Anthony Reisinger – UTB/TSC Environmental ScienceStudent Interning with NOAA this summer!

Hurricane Dolly – Category 2 – Noon (CDT) July 23rd, 2008

Gage Adjusted Rainfall

Rainfall Isohyets for Cameron County

15 m

i (24

km)

Brownsville

SouthPadreIsland

Harlingen

Impacts on Matamoros, Mexico

Impacts on Matamoros, Mexico

Impacts on Matamoros, Mexico

Impacts on Matamoros, Mexico

Impacts on Brownsville, Texas

Impacts on Brownsville, Texas

Impacts on South Padre Island, Texas

Impacts on South Padre Island, Texas

Impacts on Port Isabel, Texas

Impacts on Cameron County, Texas

Impacts on Cameron County, Texas

Impacts on Cameron County, Texas

Lessons Learned: Rainfall and streamflow data needs

• LRGV effectively only covered by KBRO station in Brownsville– Outer edge of Corpus

Christi• Severe attenuation

during storm events• Proximity to station

results in routine underprediction and scatter– Definite need for rain and

stream gages• Strong need for a dense

network of rain gages– Some showing up but not

run by a collective agency

Lessons Learned : River Flooding – Out of Sight, Out of Mind• Persistent threat of

large scale flooding from Rio Grande is not appreciated by local public– Not advertised by

agencies• Aging system of levees

in dire need of repair– International Boundary

and Water Commission (IBWC)

– Binational governance / binational action = slow to act

Rio Grande River and Levees near University of Texas at Brownsville

Evacuation Route Chokepoints

• Limited inland highway evacuation routes

• Westward and Southward movement is restricted

30-40k

150-200k

100-125k300-350k

Shelter in Place Critical for Effective Evacuation

Lessons Learned: GIS and LIDAR are reaching out to public and government officials

• LIDAR data– Now available for all of

Brownsville– Cameron County

• GIS database– City wide at local utilities

board and UT Brownsville

– Valley wide• Efforts commencing at

both UT Pan Am and UT Brownsville

• Web-based information• Need: post-storm data

and communication

Rio Grande

Detailed Floodplain and Flood Damage Reduction Alternatives Analysis Completed master planning and emergency preparedness

Lessons Learned: Need for county-wide Flood Control District

• At present, there are too many administrative / governmental agencies dealing with flooding– Cities– Counties– Local Irrigation Districts– Local Drainage Districts– IBWC– U.S. Fish and Wildlife

• Wildlife Refuges– Texas Parks and Wildlife

• Rio Grande Wildlife Corridor

Other Post-Event Issues• Long-term standing

floodwater• Tourists• Power availability

– Larger % of above ground power lines

– Redundancy for PUB• International workers

and visitors• Water supply concerns

– Minor impacts in urban areas

– Large in rural

Summary• Many needs identified for the

LRGV / Brownsville, Texas area with respect to:– Hurricane preparedness– Hydrologic/Hydraulic

information – real-time– Evacuation planning– Agency interaction

• Continue to be extremely vulnerable for the following few hurricane seasons

• Improvement due to effectiveness of state actions– Need to relay that more to

local players• SSPEED can play a central

role in this– Education and Outreach– Improved technology and

utilization of this technology