1. Caddo Lake And Lake O Pines

2. Lake Caddo Project History Project History Original Dam 1914 Original Dam 1914 Cypress Bayou Navigation Project Cypress Bayou Navigation Project Reconstruction Began August 1968 Reconstruction Began August 1968 Reconstruction Completed June 1971 (COE) Reconstruction Completed June 1971 (COE)

3. Lake Caddo Project Specific Physical Data Project Specific Physical Data 2780 mi 2 of Drainage Area Above Lake Caddo 2780 mi 2 of Drainage Area Above Lake Caddo 1900 mi 2 Uncontrolled Area (68 %) 1900 mi 2 Uncontrolled Area (68 %) 880 mi 2 Controlled By Lake O Pines (32%) 880 mi 2 Controlled By Lake O Pines (32%) 2400 Spillway @ 168.5 (860 ft) and 170.5 (1540 ft) 2400 Spillway @ 168.5 (860 ft) and 170.5 (1540 ft)

4. Cypress Bayou Basin Uncontrolled Area 1900 mi 2 or 68% Total Drainage Area Above Caddo 2780 mi 2

5. Lake Caddo Operational or Regulation Plan Operational or Regulation Plan Uncontrolled Spillway (No Human Operations Required) Uncontrolled Spillway (No Human Operations Required) Planning Studies to Look at Modifying Lake Caddo Operation Characteristics Planning Studies to Look at Modifying Lake Caddo Operation Characteristics

6. Lake Caddo Elevations (1993-2004)

7. Lake Caddo Historical Flood Data Historical Flood Data Flooding Elevation Date (ft – NGVD) Date (ft – NGVD) May 1958182.6 May 1966180.2 March 2001175.3 January 1988176.7 April 1989176.4

8. Lake Caddo Damages (2001) Flooding of Homes & Businesses Around Lake Caddo Flooding of Homes & Businesses Around Lake Caddo Costs Not Quantified Costs Not Quantified Road Closures Due To High Water Road Closures Due To High Water Overall Damage Cost Not Quantified Overall Damage Cost Not Quantified Need Available Data of Damage Costs Need Available Data of Damage Costs

9. Lake Caddo Damages (2001)

14. Lake Caddo Exceedence Probability Data Exceedence Probability Data Exceedence Elevation Probability (ft – NGVD) 1 (100-year)185.0 2 (50-year)182.7 4 (25-year)179.3 10 (10-year)175.5 20 (5-year)173.1 Source: Cypress Bayou Basin, Feasibility Report, February 1987 (2001 – 175.3)

15. Lake O The Pines Project History Project History Construction Began January 1955 Construction Began January 1955 Impoundment Began August 1957 Impoundment Began August 1957 Project Purpose Project Purpose Flood Control (Flood Control Act of 1946) Flood Control (Flood Control Act of 1946) Water Supply (Flood Control Act of 1936) Water Supply (Flood Control Act of 1936) As Requested By NE TX Municipal Water Dist. As Requested By NE TX Municipal Water Dist. 100% of Conservation Pool (201 – 228.5 ft NGVD No Flood Storage This Zone) 100% of Conservation Pool (201 – 228.5 ft NGVD No Flood Storage This Zone)

16. Lake O The Pines Project Specific Physical Data Project Specific Physical Data 880 mi 2 of Drainage Area Above Lake O The Pines 880 mi 2 of Drainage Area Above Lake O The Pines 32% Combined Lake O Pines/Lake Caddo Area 32% Combined Lake O Pines/Lake Caddo Area 200 ft Uncontrolled Spillway 200 ft Uncontrolled Spillway Maximum Capacity 68,200 cfs Maximum Capacity 68,200 cfs Outlet Works 2 – 8 ft x 12.5 ft Gates Outlet Works 2 – 8 ft x 12.5 ft Gates Maximum Controlled Release = 3000 cfs Maximum Controlled Release = 3000 cfs Top of Conservation Pool 228.5 ft NGVD Top of Conservation Pool 228.5 ft NGVD Surface area 17,649 ac-ft Surface area 17,649 ac-ft Top of Flood Control Pool 249.5 ft NGVD Top of Flood Control Pool 249.5 ft NGVD

17. Cypress Bayou Basin Total Drainage Area Above Lake O Pines 880 mi 2 or 32% Total Drainage Area Above Caddo 2780 mi 2

18. Lake O The Pines Real Estate Real Estate Federal Ownership to 236 ft NGVD (29,105 acres) Federal Ownership to 236 ft NGVD (29,105 acres) Federal Easements 236 – 254.5 ft NGVD (16,320 acres) Federal Easements 236 – 254.5 ft NGVD (16,320 acres) Damage to Structures Begin Around 242 ft NGVD Damage to Structures Begin Around 242 ft NGVD

19. Lake O The Pines Operational or Regulation Plan Operational or Regulation Plan Guidelines Guidelines Evacuate as quickly as possible to prepare for subsequent flooding events Evacuate as quickly as possible to prepare for subsequent flooding events Prevent uncontrolled spillway flows when possible Prevent uncontrolled spillway flows when possible Control 3000 cfs except when Shreveport stage > 31 ft * Control 3000 cfs except when Shreveport stage > 31 ft * Total of gaged flows for Little, Black and Big Cypress Jefferson gages not to exceed 7000 cfs Total of gaged flows for Little, Black and Big Cypress Jefferson gages not to exceed 7000 cfs Rule Curve – 230.0 (May – Sept.), otherwise 228.5 Rule Curve – 230.0 (May – Sept.), otherwise 228.5 *Note: Structural and flooding factors limit releases to 3000 cfs even though outlet works are capable of releasing more.

20. Pines Operating Rule Curve

21. 1 Day @ 200 cfs 1 Day @ 500 cfs 1 Day @ 1000 cfs 1 Day @ 1800 cfs 1 Day @ 3000 cfs 1 Day @ 1800 cfs 1 Day @ 1000 cfs 1 Day @ 500 cfs 1 Day @ 200 cfs Total Volume 400 ac-ft 1000 ac-ft 2000 ac-ft 3600 ac-ft 6000 ac-ft 3600 ac-ft 2000 ac-ft 1000 ac-ft 400 ac-ft 20000 ac-ft equivalent volume Lake O The Pines

22. Deviation Process Deviation Required To Regulate Other Than to Adopted Plan of Regulation SWF Requests Deviation To Plan SWD Reviews & Approves or Denies

23. Lake O Pines Historical Flood Data Historical Flood Data Flooding Elevation Date (ft – NGVD) Date (ft – NGVD) May 1958239.7* May 1966245.4 March 2001244.7 * Deliberate impoundment began, August 1957 with a starting water surface elevation of 208.42. Maximum pool elevation of 246.5 would have resulted if the flood would have occurred on a normal pool level of 228.5.

24. Lake O Pines Elevations (1993-2004)

25. Lake O Pines Exceedence Probability Data Exceedence Probability Data Exceedence Elevation Probability (ft – NGVD) 1 (100-year)253.5 2 (50-year)249.5 10 (10-year)239.3 20 (5-year)235.4

26. Notable Historical Floods December – March 2001 December – March 2001 Maximum Precipitation 30 Maximum Precipitation 30 Basin Average Precipitation 28 Basin Average Precipitation 28 Peak Inflow /Elevation of 25,000 cfs/244.7 ft NGVD Peak Inflow /Elevation of 25,000 cfs/244.7 ft NGVD 23 April – 2 May 1966 23 April – 2 May 1966 Maximum Precipitation 24.5 Maximum Precipitation 24.5 Basin Average Precipitation 17.5 Basin Average Precipitation 17.5 Peak Inflow/Elevation of 38,600 cfs/245.4 ft NGVD Peak Inflow/Elevation of 38,600 cfs/245.4 ft NGVD 25 April – 4 May 1958 25 April – 4 May 1958 Maximum Precipitation 18.1 Maximum Precipitation 18.1 Basin Average Precipitation 15.3 Basin Average Precipitation 15.3 Peak Inflow/Elevation of 69,200 cfs/239.7 (246.9) ft NGVD Peak Inflow/Elevation of 69,200 cfs/239.7 (246.9) ft NGVD

27. Lake Caddo & Lake O Pines December – March 2001 Flood Event December – March 2001 Flood Event Long Duration Event Long Duration Event Extremely High Rainfall Accumulations Extremely High Rainfall Accumulations Pines Basin Average 27.3 Pines Basin Average 27.3 Caddo Basin Average 28.3 Caddo Basin Average 28.3 Continued Rainfall Prevented Evacuation Continued Rainfall Prevented Evacuation

28. Cypress Bayou Basin (December 2000 – March 2001 Rainfall)

29. Lake Caddo Inflow

30. Caddo Inflow w/ Pines % Pool Occupied

31. Lake Caddo Elevations

32. Lake O Pines Inflow & Release

33. Lake O Pines Elevations

34. Flooding of Homes & Businesses Around Lake O Pines Flooding of Homes & Businesses Around Lake O Pines Costs Not Quantified Costs Not Quantified Damage to Spillway Approach, Parks, Recreational & Other Government Facilities Damage to Spillway Approach, Parks, Recreational & Other Government Facilities $1,155,000 ($900,000 Spent to Date) $1,155,000 ($900,000 Spent to Date) Marinas Marinas Costs Not Quantified Costs Not Quantified Road Closures Due To High Water Road Closures Due To High Water Overall Damage Costs Not Quantified Overall Damage Costs Not Quantified Splitter wall failed below outlet works Splitter wall failed below outlet works Lake O Pines Damages (2001)

40. Lake O Pines Erosion (2001)

41. Summary Operational Plan for Lake O Pines Operational Plan for Lake O Pines Limit, Not Totally Prevent, Downstream Flooding Limit, Not Totally Prevent, Downstream Flooding Minimize Uncontrolled Spillway Discharges Minimize Uncontrolled Spillway Discharges Ensure Safety of Dam Ensure Safety of Dam Limited Flood Storage In Lake O Pines Limited Flood Storage In Lake O Pines Flood Water Must Be Quickly Evacuated Flood Water Must Be Quickly Evacuated Majority of Runoff into Lake Caddo is From the Uncontrolled Area (68 %) Majority of Runoff into Lake Caddo is From the Uncontrolled Area (68 %) Historically Lake O Pines Reduces Lake Caddo Elevations 3-5 ft Historically Lake O Pines Reduces Lake Caddo Elevations 3-5 ft The 2001 Flood Was a 10-year Event The 2001 Flood Was a 10-year Event

42. Lake Caddo Recent Planning Studies For Lake Caddo Recent Planning Studies For Lake Caddo Reconnaissance Report, Cypress Valley Watershed, Texas, September 1995 Reconnaissance Report, Cypress Valley Watershed, Texas, September 1995 Environmental Emphasis Environmental Emphasis Flood Reduction Options for Caddo Lake Included Flood Reduction Options for Caddo Lake Included More Efficient Spillway More Efficient Spillway Downstream Channelization of Twelvemile Bayou Downstream Channelization of Twelvemile Bayou No Local Sponsor Identified No Local Sponsor Identified

43. Lake O Pines & Caddo Elevations (1993-2004)

44. Lake O Pines Outflows (1999-2001)

45. Lake O Pines Outflows (2002-2004)

46. Questions?