2. Lake Livingston Map Cape Royale North Strong North/Northwest Winds ~ 40 to 60 MPH sustained Livingston Dam

3. Inland Lake Surges Associated with Hurricanes Rita and Katrina Dave Schwertz, CFM Senior Service Hydrologist Lance Wood Science and Operations Officer NWS Houston/Galveston

4. Large Coastal Lake Surges  The SLOSH model is run in advance for potential surges on Lake Okeechobee and Lake Ponchatrain.  Catastrophic surges on these lakes have occurred and have been well documented and modeled.  In 1928, a storm surge on Lake Okeechobee overtopped the levee and killed 2,500+ people in Belle Glade and other small surrounding towns.  The surge associated with hurricane Katrina (2005) did not overtop the levee system around Lake Pontchartrain, but caused several levee breaches.

6. Lake Okeechobee Map Belle Glade North Storm Track

7. Katrina Storm Surge Actual Model Run Gulfport, MS

8. New Orleans Flooding Levees were breached not overtopped by storm surge Much worse if the storm surge had overtopped them Flooding that took 2 days would have occurred in 6 hours Levee Breach Levee Breach

9. Inland Lakes/Reservoir Surges from 2005 Pearl River at Ross Barnett Reservoir Hurricane Katrina (August 29 th,2005) Trinity River at Lake Livingston Hurricane Rita (September 24 th, 2005)

10. Lake Livingston Dam Following the state-approved emergency action plan, the Trinity River Authority began releasing water from Lake Livingston to lower the water level to 127 feet above sea level to avoid any further erosion of the rip rap or the soil on the dam from wave action during the hurricane event. Lake Livingston Dam is a 2.5 mile earthen embankment with 12 tainter gates for releasing water. The earthen embankment is protected from water erosion by rip rap, large 30 inch diameter stones, on the lake side of the dam. Built, owned and operated by the Trinity River Authority of Texas (TRA), Lake Livingston is the largest lake constructed solely for water supply purposes located totally within the State of Texas. The lake covers approximately 83,000 surface acres (130 sq. miles), with a normal pool elevation of 131 feet above mean sea level. The Livingston Dam, constructed across the Trinity River approximately seven miles southwest of the city of Livingston, is 2 1/2 miles in length and has an average height of 55 feet.

11. Inland Lake/Reservoir Surges from 2005 Trinity River at Lake Livingston San Jacinto River at Lake Conroe

12. Inland Lake/Reservoir Surges from 2005 Pearl River at Ross Barnett Reservoir Hurricane Katrina (August 29 th,2005) Trinity River at Lake Livingston Hurricane Rita (September 24 th, 2005) San Jacinto River at Lake Conroe Hurricane Rita

13. Lake Livingston Dam  Lake Livingston Dam is a 2.5 mile 55 foot high earthen embankment with 12 tainter gates for releasing water.  The earthen embankment is protected from water erosion by rip rap, large 30 inch diameter stones, on the lake side of the dam.  Built in 1966, owned and operated by the Trinity River Authority of Texas (TRA), solely for water supply purposes.  The lake covers approximately 83,000 surface acres (130 sq. miles), with a normal pool elevation of 131 feet above mean sea level and is located 7 miles southwest of Livingston.

15. Hurricane Rita Radar Images KHGX reflectivity @301 AM CDT around time of landfall (95 miles SE of the dam) KHGX reflectivity @550 AM CDT Rita centered near Mauriceville, TX (75 miles ESE of the dam)

16. Lake Livingston

17. 117 MPH gust at Dam (530 AM) Civil Emergency Message issued to evacuate below Dam (147 PM) Peak of storm surge (8 AM) Releasing 80K CFS Peak drop in water level at north end of lake (Riverside 1200 PM) Hurricane Rita making landfall near Sabine Pass (3 AM) Lake Livingston

18. Lake Livingston Map Riverside North Strong North/Northwest Winds ~ 40 to 60 MPH sustained Livingston Dam

19. Damage at the Livingston Dam The high winds and significant wave action brought by Hurricane Rita eroded some of the rip rap on the lake side of the dam, exposing part of the earthen embankment. Some erosion to the earthen embankment has also occurred.

20. Emergency Releases Following the state-approved emergency action plan, the Trinity River Authority began releasing water from Lake Livingston to lower the water level to 127 feet above sea level to avoid any further erosion of the rip rap or the soil on the dam from wave action during the hurricane event.

22. Damage at the Livingston Dam The high winds and significant wave action brought by Hurricane Rita eroded some of the rip rap on the lake side of the dam, exposing part of the earthen embankment. Some erosion to the earthen embankment also occurred. 9.6 million dollars worth of repairs were necessary.

23. Indian Hills Subdivision Damage These lots faced N/NW and bore the brunt of the surge Indian Hills Subdivision Damage These lots faced N/NW and bore the brunt of the surge

24. Lake Conroe Extending 21 miles in length and covering 21,000 surface acres, Lake Conroe is the reserve drinking water supply for the city of Houston NorthNorth Strong North/Northwest Winds ~ 30 to 40 MPH sustained Peak Gusts ~ 50 to 60 MPH

25. Lake Conroe Dam Damage Erosion of the Lake Conroe Dam (Image from the Montgomery County News) Wave action scoured the face of Lake Conroe's dam, exposing the dam's clay core. Although the dam was never in danger of collapsing, the river authority was left little choice but to drop the water level nearly 5 feet so workers could repair the damage and beef up the structure. Repairs to the dam cost 1.7 million dollars.

26. Ross Barnett Reservoir Ross Barnett Reservoir (52 sq mi) is on the border of Madison and Rankin counties in central Mississippi on the Pearl River, 5 miles NE of Jackson. The reservoir is a fairly shallow lake extending ~15 miles from northeast to southwest. The dam is 64 ft high and was built for recreation. It is also used for flood control and water supply. During the height of the storm, waves were washing over the top of the dam. Wave actions severely damaged the rip rap in the upper portions of the dam and in fact washed it away in some areas. Reservoir officials ordered a special release of up to 40,000 CFS of water from the dam to relieve the pressure on the dam. Katrina did about two million dollars worth of damage to the dam and severely damaged the causeway to the north shore of the reservoir.

27. Hurricane Katrina Radar Images KDGX Composite Reflectivity Center Southwest Of Hattiesburg, MS 1202PM KDGX Composite Reflectivity Center Southwest of Meridian, MS 4:03 PM Ross Barnett Reservoir

28. Ross Barnett Map Ross Barnett Map Ratliff’s Ferry Ross Barnett Reservoir Dam 15 miles NE to SW Pearl River 5 NE Jackson Strong Northeasterly Winds ~ 45 Gusting to 75 MPH North Primarily Recreation also used for Flood Control and Water Supply $2 million damage to dam Severe damage to causeway to north shore

29. Peak Drop in Lake at Ratliff’s Ferry (Upper Ross Barnett Reservoir) between 4pm and 5pm. Peak of Storm Surge (4pm) Katrina Landfall in South Louisiana ~ 6AM Reservoir officials give order to release up to 40K to take pressure off of the dam (~5pm) Ross Barnett Pool & Ratliff’s Ferry Pool

31. Peak Pool at Ross Barnett Reservoir Dam 298.11 at 4pm. Ratliff’s Ferry Pool dropped to 295.80 at 4pm Ratliff’s Ferry (Upper Ross Barnett Reservoir) Ross Barnett Reservoir Pool Rise in pool: 0.72 feet Discharge increase: 15,565 CFS

32. Peak Surge occurred at Dam (4pm) Peak Discharge from Reservoir 35,340 CFS (630pm) Ross Barnett Discharge (CFS)

33. Thank you for your attention ! Any Questions ? Dave.Schwertz@noaa.gov