San Antonio River Authority Floodworks implementation in the San Antonio River Basin Nefi Garza, PE, CFM San Antonio River Authority Michael Crenshaw, PE, CFM Anthony J. Henry Wallingford Software, Inc
San Antonio River Authority Established May 5, 1937
HWY 281 looking south 2002 Olmos Basin Flash Flood Alley
Flash Flood Alley IH 10 looking North 2002 Leon Creek
Regional Flood Challenges Watershed response times are fast Often less than 1 hour Stream velocities are high Velocities greater than 6 fps are common Event magnitudes are unbelievable
South Texas Rainfall Records Thrall (1921): 36 /18 hrs Ingram (1932): 36 /24 hrs D Hanis (1935): 22 /3 hrs Pandale (1954): 32 /24 hrs New Braunfels (1972): 10 /1 hr TS Amelia (1978): 48 /52hrs TS Claudette (1979): 43 /24 hrs Zorn (1998): 32 /18 hrs TS Charley (1998): 18 /4 hrs Kerr County (2002): 42 /5 days Source: NWSFO Austin/San Antonio
Operational Rain/Stage Units
Fully Operational Coverage
Previous Flood Warning Efforts City of San Antonio Flood Warning System 85 ALERT/IFLOWS stations. 19 low water crossing lights. 21 stations currently operating. CRWR Map to Map Brainchild of Dr. David Maidment at the University of Texas Center for Research in Water Resources. Funded by SARA. Integrated modeling and mapping in ArcGIS. Evolved into BRWM Regional Watershed Modeling System. Lower Basin Flood Warning Response System Built in cooperation with the U.S. Army Corp of Engineers. Based on the Susquehanna FWRS. Static inundation areas pieced together using forecast flood elevations. Flood response tables maintained by emergency managers in respective counties.
From a NEXRAD Map to a Floodplain Map Center for Research in Water Resources CRWR Component 3: Creating a Flood Inundation Map Component 1: Importing NEXRAD data into Geodatabase and Mapping to Watersheds NEXRAD Data Component 2: Hydrologic & Hydraulic Integration based on common geographic framework Hydrologic Model HEC-HMS Hydraulic Model HEC-RAS FLOODPLAIN MAP Salado Creek, San Antonio Rosillo Creek NEXRAD Rainfall Watersheds Geographic Integration using Arc Hydro Process Operations using Arc 9 Model Builder Component 3 Component 1 Component 4 Component 4 Component 2 Component 4: Geodatabase to HEC-DSS to Geodatabase Component 4 Component 3: Floodmapping from HEC-RAS GIS SDF File DEM Cross Sections with Water Surface Elevations Water Surface Raster Flood Inundation Polygon Time Series in HEC-DSS Time Series in Geodatabase HEC Data Storage System for Time Series Research funded by The San Antonio River Authority
Implementation Lower Lower Basin FWRS Static maps to simulate flood inundation Product of ACOE study of Wilson, Karnes, and Goliad Counties ArcGIS application Recently converted to web application Bexar Bexar County FWRS Real-time monitoring, modeling, and mapping Pilot study on Salado Creek is complete Event simulation challenge on Six Mile Creek in progress Coordination with all agencies on EFWS station location/funding in progress DFIRM model conversion in progress
Lower San Antonio River HEC-FWRS
SARA EFWS/FWRS Map data Model scenarios Collect data Map results
Lower Basin FWRS
Lower Basin FWRS
Lower Basin FWRS
Web-FWRS Login
Web-FWRS Main View
Web-FWRS Forecast View
Web-FWRS Magnifier
Web-FWRS Damages
Web-FWRS Response Table
Bexar County Flash flood monitoring & Real Time modeling
FEMA DFIRM Project In early 2005 the Federal Emergency Management Agency (FEMA) approached us to update all the flood zone in our 4 counties starting with Bexar County, the most populated. We agreed that this was need in our basin FEMA provided Approximate just over 1.2 million SARA provided over 12 million in matching funds For a total of 13.2 million to update the model in Bexar County and another 3 million for the remaining 3 counties We have a pretty complete modeled Basin
Streams and rivers to be modeled and re mapped Over 1700 stream miles in Bexar County
The FEMA Models The FEMA models are all HEC-HMS HMS (hydrology) and HEC-RAS (hydraulics) The Hydrology component uses an areal reduction factors to attempt to simulate a storm cell The Hydraulic models are all steady state www.bexarfloodfacts.org www.sarafloodfacts.org
InfoWorks Demo
Conceptual Architecture EAA Models CoSA WSFO SARA Rain db RFC Models EOC USGS
Design Data Flow
Salado Creek Test
Salado Creek Test
Salado Creek Test Data from pilot study on Salado Creek
Salado Creek Test
Comments/Questions Nefi Garza, PE, CFM San Antonio River Authority ngarza@sara-tx.org