1. Question of the day: How is a Tucson flood like a redneck divorce?

2. Rainfall in southern Arizona A Case of Famine and Feast

3. General airflow from Pacific
Digital Elevation Map
Colorado Plateau
General airflow from Pacific
Mogollon Rim
Basin and Range
You are here.

4. Annual Precipitation
Sky Islands of SE Arizona

5. Anatomy of River Valley
Main channel is normal course of river.
Floodplain is area covered during flood.
Over geologic time, river meanders over floodplain.

6. Typical flood hazard is water covering the floodplain.

7. Major Drainages of Tucson Basin

8. Flow Gauge Records, Santa Cruz River
1983
1914
1965
1977
1983 flow = 53,000 cfs
(Equivalent to 16 backyard swimming pools per second!)
25% above previous 100-year flood estimates.
More frequent record flows post 1960

9. 1983 Santa Cruz River @ Congress

10. Santa Cruz River @ Congress

11. Rillito at First Avenue, Oct. 1983
Bank erosion along the outside of a meander bend

12. October, 1983 flood: 8 deaths, ~1000 injuries; $250 million damage.
Active river channel moves by bank erosion. This is principle flood hazard in Tucson.
Rillito Creek at First Avenue, Tucson, 1983
October, 1983 flood: 8 deaths, ~1000 injuries; $250 million damage.

13. Increased frequency of record Santa Cruz flows since 1960. A
Increased frequency of record Santa Cruz flows since A. Climatic effect? Global warming? Enhanced El Nino? B. Urbanization? Urbanized desert increases runoff by four times compared to undeveloped desert.

14. Effects of Urbanization on Stream Flow
Before
After
Urbanization decreases lag time and increases maximum flow.

15. Flood Forecasting
100-year flood projections depend on models of climate and hydrology.

16. Flood Control Measures A
Flood Control Measures A. Structural Dams Channelization Diversion channels B. Nonstructural Zoning and land-use restrictions Land acquisition programs Flood forecasting Public education
Pima County

17. Soil cementing, Rillito @ Campbell
Confine the flow. Move the water out of Tucson ASAP.

18. A: Sooner or later, someone’s going to loose a trailer.
Q: How is a Tucson flood like a redneck divorce?
A: Sooner or later, someone’s going to loose a trailer.

19. Teton Dam on Snake River

20. Beginning of water piping and erosion of earthfill.

24. Complete failure

25. Permeable volcanic rock in footings of Teton Dam