Onion Creek Flooding, 30 October 2013
Number of buyouts by the City of Austin in the Onion Creek area – 323 homesApproximate amount spent on buyouts - $36 million ($8M of this from FEMA grant funding)
A flooded home location
FEMA Flood Hazard Zone
Drainage Area above HomeDrainage area = 732 km2, or 282 miles2
Variation in SLOSH Model Storm Surge Elevations at Developed Shoreline
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
Shoreline Locations - Not to scaleSt
orm
Sur
ge E
leva
tion
(ft m
sl)
Cat 5Cat 3Cat 1
PRELIMINARYsource: FEMA MAT, 2-26-06
Flood Water Elevations
Halloween Flood on Onion Creek Expected Hurricane Storm Surge Heights on Gulf Coast
Halloween Flood ~ 120,000 cfs
Somewhere between 20 yr and 100 yrreturn period, perhaps 50 yrs
Halloween Flood
HEC-SSP Flood Frequency Analysisfull flood record
http://crhphotos.com/2013/10/halloween-2013-flood/