2. Flood Warning and Forecasting Issues in the SRWMD

3. Suwannee River Basin Georgia Florida 240 Miles Long, 9,950 Square Miles Headwaters Okefenokee Swamp: Suwannee River Cordele, GA: Alapaha River Tifton, GA: Withlacoochee River State Line at River Mile 207 Only 43% of Basin is in Florida

4. Suwannee River Basin Non-Structural Floodplain Management Strategy n Floodplain Regulation n Floodplain Acquisition n Forecasting and Education

5. Floodplain Regulation Elevate Structures Elevate Structures n Limit Fill and Obstructions in Floodplain n Riverbank Setbacks and Erosion Control

6. Floodplain Acquisition Strategy n Provide natural storage for flood waters n Reduce loss of life and property due to floods n Protect ground and surface water resources n Protect natural systems associated with floodplain ecosystems

7. Flood Warning and Education n Emergency Management Coordination n Flood Forecast Modeling n Forecast Dissemination –Telephone –Internet –NOAA Weather Radio

8. Georgia Florida Flood Monitoring Network in the Suwannee River Basin USGS-GA USGS-FL SRWMD

9. Georgia Florida Flood Forecast Points in the Suwannee River Basin USGS-GA USGS-FL SRWMD

10. Automated Rainfall Network Current Station Planned Station

11. Major Floods in the Suwannee Basin n 1928 - Earliest Documented Flood n 1948 - Flood of Record on Alapaha, Withlacoochee, Suwannee below Ellaville n 1964 - Hurricane Dora - Flood of Record on Santa Fe River n 1973 - Flood of Record at White Springs and Suwannee Springs n 1998 - Roughly a 20-year flood

12. Recent Flood Events on the Santa Fe n March/April 1991 - Last major Suwannee flood before 1998 El Niño n 1992 – October Surprise n February/March 1998 - Highest water in upper Santa Fe since 1964 n March 2003 – NWSRFS Model Tune-up

13. 10/92 9/85 9/88 Pure Santa Fe Flood 3/91 3/98 3/86 2/91 4/84 Pure Suwannee Flood 4/91 2/98 Mixed Flood

14. Monitoring Goals n Obtain near-real-time river level and rainfall data for forecast model input n Improve our understanding of the interaction between ground and surface water Develop/maintain tools for evaluating changes in flow ratings in the Suwannee River Basin Develop/maintain tools for evaluating changes in flow ratings in the Suwannee River Basin

15. Rating Mechanics n Primarily stage versus discharge n Model mechanics n If stage-discharge relationship is unreliable, river forecast results will be unreliable.

16. Rain, Soil Moisture, Travel Time

17. Rose Creek/Walter Little Road

21. Vertical Datum Upgrade Issues NAVD88 is about 9 inches below NGVD29 All gages are currently in NGVD29 All modeling is currently in NGVD29 Not all surveying may be in NGVD29

23. Suwannee River at Dowling Park

24. Old Highway Bridge at Dowling Park