South Central Texas October, 1998

Storm Summary
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Fatalities,
Survivors
& Rescue Efforts
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Property Damage
& Relief Efforts
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Success Stories
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Regional Flood
Histories
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Local
Programs
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Resources
& Publications
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Known Hazards
in Central Texas
Flood Clean Up after 30 inches
October
1998

South Central Texas
October, 1998
Max. Precipitation: 30 inches
Deaths: 32
Damage: 1.5 Billion (approx.)

Floods in the Guadalupe and San Antonio River Basins in Texas,
October 1998

Severe flooding in parts of south-central Texas resulted from
a major storm during October 17-18, 1998. The flooding occurred
in parts of the major streams and tributaries of the San Jacinto,
San Benard, Colorado, Lavaca, Guadalupe, and San Antonio River
Basins. Peak gage height, peak streamflow, and documentation of
the significance of the peaks were compiled for the streamflow-gaging
stations where the storm caused substantial flooding. This information
is available on the U.S. Geological Survey (USGS) world-wide web
site at http://tx.usgs.gov/alert/oct_floods_98.html.

Read More >

 

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Flood Map

Open USGS PDF

Staying Safe During a Flood

GBRA ”
Staying Safe”
Publication on ’98 Floo
d

The majority of the water fell in the upper
river basin (as opposed to the lower basin deluge of ’98). This
brought Canyon Dam into its most important role since it was built
in 1932? At the flood peak, the dam held back 70, 000 cfs – though
70,000 more escaped over the spillway as it was designed to do.

See more >

 

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Texas Storm Map

Full
Size

The San Antonio River Tunnels proved their
value to that city as they diverted water safely underneath downtown.
Construction on these tunnels was finished by the San Antonio
River Authority just months before the massive storm hit.

 

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River Tunnel

Full Size

Storm Description
(from
USGS storm summaries
)

October 17 to 18, 1998

Up to 30 in. of rainfall occurred in a 2-day period–about
5,000 square miles in parts of 19 counties received at least 8
in. of rain. Thirteen streamflow-gaging stations in the Guadalupe
and San Antonio River Basins recorded peak discharges equal to
or greater than the 100-year peak and record-breaking peak discharges
were recorded at 11 of the stations. read
more…

Deaths and Damage:   Thirty-two lives were lost and property
damage was estimated to be approximately one billion dollars.

Max. Precipitation:   30.00 in. (Hays Co.) 22.00 in. (Comal
Co.)

Severity:   Catastrophic

Storm Center(s):   Hays Co., San Marcos Comal Co.

References:   Slade and Persky, 1999


http://water.usgs.gov/pubs/FS/FS-147-99/

The storms produced large volumes of runoff and as many as four
flood peaks at each of many streamflow-gaging stations in the
Brazos, Colorado, and Guadalupe River Basins. Record flood stages
occurred at sites on the Medina River, San Antonio River, Sabinal
River, and Nueces River. For the first time since it filled in
1968, Canyon Lake (northeast of San Antonio) poured over its spillway,
adding to the flooding in the Guadalupe River. Emergency managers
also were concerned about the 90-year-old dam at Medina Lake (west
of San Antonio). Medina Lake topped its spillway and rose to within
18 inches of the top of the dam. Areas downstream from the dam
were evacuated as a precaution to the fear of dam failure.

 

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