1. Flooding adapted from a presentation by Prof. David R. Maidment

2. Flooding Manawatu, New Zealand

3. Bridges that Work

4. Bridges that don’t work
Small bridge on a country road is washed away

5.
Most costly urban flood disaster in the history of the United States

6. Major Highways during Tropical Storm Allison
I-10 West
I-45 South

7. Kayaking on US 59, Houston (Tropical Storm Allison)

8. Residential Flooding in Tropical Storm Allison

9. The Human Cost Saving the wedding photos Cleaning out the car

10. 5-day rain total (Tropical Storm Allison)
City of Houston
Harris County

11. 12-hour rain total (Tropical Storm Allison)

12. Extreme Rainfall Statistics (Tropical Storm Allison)

13. 73,000 houses and apartment buildings flooded

14. Watersheds Stream gaging station Watershed = area that drains to
a particular river or stream network

15. Floodplain maps (White Oak Bayou, Houston)

16. What can we do about floods?
Engineering structures
Dams and detention ponds to hold back flood waters
Increase capacity of streams to carry floods
Better flood planning
Create floodplain maps to define at-risk areas
Restrict building foundations are at least 1 foot above 100-year flood elevation
Develop flood forecasting and warning systems

17. Regional Storm Water Modeling Program and Master Plan for San Antonio
City of
San Antonio
Good morning.
It’s my pleasure to share with you an example of regional cooperation within Bexar County.

18. San Antonio Regional Watershed Modeling System
Geospatial Data:
City, County
SARA, other
“Bring the models
together”
Modeling
System
Rainfall Data:
Rain gages
Nexrad
Calibration Data:
Flows
Water Quality
Floodplain
Management
Capital
Improvement
Planning
Water quality
planning
Integrated
Regional Water
Resources planning
Flood
Forecasting

19. Nexrad Map to Flood Map in Arc 9 Model Builder
FLOODPLAIN MAP
Flood map
as output
Model for
flood flow
HMS
Model
for flood
depth
Nexrad rainfall map as input

20. TxDOT Sand Filter

21. Central Park Wet Pond (Austin)

22. Extended Detention Basin
After the basin had been in operation for several months. Two outlet risers to get the capacity for flood control, since this is a flow through EDB, couldn't put any more of a backwater on the existing upstream SD.
There was a buried bridge at this locaiton, not shown on the as-builts, large amounts of broken concrete with rebar. We took two boring logs, niether hit the material. The CCO for this site exceeded the bid price for the basin.
The contractor constructed the outlet too high, ended up leaving that, with reduced slope between inlet and outlet, a retrofit issue.