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Success Story: Eradication of Hydrilla at Lake Murray ( and continued success in the rest of the State)

Success Story: Eradication of Hydrilla at Lake Murray ( and continued success in the rest of the State). Western Regional Panel La Jolla, CA Sep 10, 2003. Success Story. CDFA legal authority to eradicate hydrilla Quick overview of hydrilla

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Success Story: Eradication of Hydrilla at Lake Murray ( and continued success in the rest of the State)

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  1. Success Story: Eradication of Hydrilla at Lake Murray (and continued success in the rest of the State) Western Regional Panel La Jolla, CA Sep 10, 2003

  2. Success Story • CDFA legal authority to eradicate hydrilla • Quick overview of hydrilla • Lake Murray (thanks to Jeffrey Pasek from the City of San Diego Water Dept.) • Overview of current hydrilla eradication projects WRP 09/11/2003

  3. Success Story: Lake Murray • Why review Lake Murray ? • Good example of a successful large scale eradication effort • Demonstrates essential components of a successful eradication program WRP 09/11/2003

  4. CDFA Hydrilla Eradication Program • Legal authority • California Food and Agriculture Code • Section 6048: Secretary of Agriculture authorized to survey and eradicate hydrilla (1977) • Section 405: Secretary of Agriculture authorized to prevent introduction and spread of noxious weeds • California Code of Regulations • Section 4500: lists hydrilla as State noxious weed • Title 7, Code of Federal Regulations • Section 360: lists hydrilla as Federal noxious weed (1974) WRP 09/11/2003

  5. Hydrilla: a Federal and State Aquatic Noxious Weed • Two forms • Monoecious • Dioecious • Forms impenetrable mats • Tubers form a long term bank • Spread mostly by human activity WRP 09/11/2003

  6. Lake Murray 171 surface acres 65 feet, max water depth 3.2 shoreline miles WRP 09/11/2003

  7. History of the Project • Hydrilla first detected in Lake Murray in 1976 • Limited quarantine imposed in 1977 • Full quarantine imposed in 1979 • Lake closed to water-based public recreation • Boats, fishing, water contact prohibited • Project goals • Prevent spread of hydrilla to other waters • Eradicate hydrilla in Lake Murray WRP 09/11/2003

  8. History of the Project - cont. • Eradication began in 1979 • 1977-1994: reservoir water level drawdown • 1979-1984: herbicide applications • 1985-1991: mechanical removal using SCUBA divers and suction dredge • 1992-1994: on-going inspections • Water-based recreation gradually re-established, beginning in mid-1980’s • Last plant found July 1991 • Declaration of eradication November 1994 WRP 09/11/2003

  9. Initial Infestation: 1977 • Covered 80 acres(of a total of 170 surface acres) • All of the lake area less than 20 feet deep • Continuous mat along shoreline • Probably introduced from aquarium WRP 09/11/2003

  10. Water Level Drawdown: 1977-1994 • Water level dropped 30 feet • Late summer • Exposed plants killed by drying • Some roots and tubers survive WRP 09/11/2003

  11. Water Level Drawdown WRP 09/11/2003

  12. Komeen Herbicides: 1979-1984 ® Vapam ® WRP 09/11/2003

  13. Eradication: Initial Phase • Combination of water level draw downs and herbicides reduced infestation by 90% • By 1984 only isolated individual plants remained • Herbicides and drawdown not effective for remaining infestation WRP 09/11/2003

  14. Underwater Inspections,SCUBA WRP 09/11/2003

  15. Suction Dredging: 1985-1991 • SCUBA divers removed individual plants • Labor intensive • Removed remaining 10% of infestation WRP 09/11/2003

  16. Suction Dredging WRP 09/11/2003

  17. Eradication Complete: 1994 1977 1994 WRP 09/11/2003

  18. Success Story: Lake Murray WRP 09/11/2003

  19. Success Story: Lake Murray WRP 09/11/2003

  20. Project Costs • Direct Costs $5,700,000 • 1979 – 1984: ~$200K per year • herbicide applications, quarantine, drawdown • 1985 – 1991: ~$600K per year • mechanical removal, SCUBA inspections, drawdown • 1992 – 1994: ~$90K per year • on-going surveys and draw downs • ~$71,000 per acre of originalinfestation WRP 09/11/2003

  21. Project Costs • Indirect costs • Reduced use of Lake Murray as a water supply reservoir • Loss of revenue from public recreation program • Loss of use of Lake Murray for public recreation WRP 09/11/2003

  22. Lessons Learned • Quarantine can be effective to prevent spread • Methods used for initial eradication probably won’t work in final stages • Eradication can be a long and costly effort WRP 09/11/2003

  23. Success Story: rest of the State WRP 09/11/2003

  24. COUNTY* YR WATER BODY SIZE STATUS CALAVERAS 88 88 96 Bear Creek/ and 3 ponds Two ponds Bear Creek, 2 ponded areas 23 acres 0.6 acre 26 acres Survey  Active Active IMPERIAL 77 45 ponds/reservoirs Imperial Irrigation System 270 acres 600 miles of canals, ditches Survey Active LAKE 94 Clear Lake 1,440 acres / 43,000 acres Active LOS ANGELES 80 83 85 Eight ponds One pond One pond 2 acres <1 acre <1 acre Erad. Erad. Erad. MADERA/ MARIPOSA 89 Eastman Lake Chowchilla River 100/1,800 acres 26 miles Active Active MONTEREY 78 Private pond 0.01 acre Erad. RIVERSIDE 77 84 85 One pond One pond Three ponds <1 acre <1 acre <1 acre Erad. Erad. Erad. Status of Hydrilla in California WRP 09/11/2003

  25. SAN BERNARDINO 88 One pond <.01 acre Erad. SAN DIEGO 77 77 Lake Murray One pond 160 acres <1 acre Erad. Erad. SAN FRANCISCO 88 One pond 2 acres Erad. SANTA BARBARA 77 93 One pond One pond 0.12 acre <.01 acre Erad. Erad. SHASTA 85 86 94 96 Seven ponds Four ponds Two ponds Four ponds 133 acres 23.5 acres 13 acres 39 acres Erad. Erad. Survey Active SONOMA 84 Spring Lake 72 acres Erad. SUTTER 85 One pond <.01 acre Erad. TULARE 93 96 Three ponds Seven ponds 0.6 acre 20 acres Erad. Active YUBA 76 90 97 Lake Ellis One pond 13 ponds and two spill basins 30.8 acres 6.0 acres 20 acres and 3.1 miles of canal Erad. Erad. Active Status of Hydrilla in California WRP 09/11/2003

  26. Springville ponds, before/after Komeen treated lanes 1996 WRP 09/11/2003 2002

  27. Chowchilla River, before/after 1989 WRP 09/11/2003 Dec 2001

  28. WRP 09/11/2003

  29. Lake County Project • Surveys in Clear Lake • Visual, Grappling hook • 2001, 1042 surveys • 2002, 790 surveys • Treatments: aquatic herbicides • Fluridone slow release pellets • Copper ethylenediamine WRP 09/11/2003

  30. Clear Lake WRP 09/11/2003

  31. Success Story: rest of State • Lessons learned • Eradication is feasible • Requires early detection and rapid response • Requires long-term dedication of funds and manpower • Requires technology appropriate to the situation and phase of eradication WRP 09/11/2003

  32. Success Story: Lake Murray • Many thanks to Jeffrey Pasek for his slides for this portion of presentation • Thanks to City of San Diego and the San Diego County Agricultural Commissioner for their support in the eradication of hydrilla from Lake Murray. WRP 09/11/2003

  33. COOPERATORS • U.S. Department of the Interior-Bureau of Reclamation • U.S. Department of Agriculture-Animal and Plant Health Inspection Service • U.S. Army Corps of Engineers-Eastman Lake • Dept. of Boating and Waterways • Dept. of Water Resources • Yolo County Flood Control and Water Conservation District • County Dept.s of Agriculture WRP 09/11/2003

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