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FEMA Flood Insurance Rate Map Update FEMA Public Meeting October 22, 2009

FEMA Flood Insurance Rate Map Update FEMA Public Meeting October 22, 2009. FEMA Initiates Levee Reaccreditation Every 5 Years. Pole Crk Channel (WPD). Pole Crk Debris Basin (WPD). Heritage Levee (City). Levees Expected to be Accredited by November 2009.

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FEMA Flood Insurance Rate Map Update FEMA Public Meeting October 22, 2009

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  1. FEMA Flood Insurance Rate Map UpdateFEMA Public MeetingOctober 22, 2009

  2. FEMA Initiates Levee Reaccreditation Every 5 Years Pole Crk Channel (WPD) Pole Crk Debris Basin (WPD) Heritage Levee (City)

  3. Levees Expected to be Accredited by November 2009 Non accredited levees cause Flood Zone A Accredited: Non Accredited: Pole Crk Channel (wpd) Pole Crk Debris Basin (WPD) Heritage Levee (City)

  4. Years to Accreditation 6 to 12 Accredited: Non Accredited: Pole Crk Channel (WPD) 3 to 10 4 to10 Pole Crk Debris Basin (WPD) Future Heritage Levee (City) 1 to 6

  5. HISTORY OF SESPE CREEK LEVEE 1978: Los Serenos Flood 1979: Q-100 = 98,000 CFS 1983: COE Sespe Levee - 121,000 CFS 1979 to 2009: 6 Large Flood Flows 2006: Q-100 = 135,000 CFS

  6. Los Serenos 1978 Flood (pre-levee) T E C H N I C A L S T U D I E S

  7. Improved Hydraulic Analysis Since 1979 1979: HEC 2 – One Dimensional Flow Analysis 2009: HEC RAS + Flow 2 D – Two Dimensional Flow Analysis Better projection of flow from island crossover

  8. Main Channel Shifts from West to East (1938 – 2008) 1938 1975 2005 T E C H N I C A L S T U D I E S

  9. Scour and Aggradation (1970s, 2004, & 2005 topography) 10 T E C H N I C A L S T U D I E S

  10. SC-1 Levee - Phase 3 Certification Action Plan Cost Estimate: $824,500

  11. Preliminary PlanRetrofit the USACE Levee 1’ 6’ 1’ Raise levee 1 to 6 feet Preliminary initial cost $6,500,000 Deepen Foundation?+3X$ A L T E R N A T I V E S A N A L Y S I S 12

  12. Possible Modification/Replacement of Hwy 126 Bridge • Extension/replacement of exist. structure • Options: 90’ extension; Raise existing structure • Cost: $13,000,000 or $44,000,000 • Possibly Non effective A L T E R N A T I V E S A N A L Y S I S

  13. Summary of Key Sespe Issues Increase in estimated peak flow rates based on additional stream gage data (+35% compared to 1979 analysis) Shift of dominant channel from west to east fork Active channel changes with major storm events Lower reach of USACE levee does not meet Federal requirements Long-term sediment deposition and local erosion Levee foundation must be checked for adequacy for the new 100 year flow T E C H N I C A L S T U D I E S 14

  14. Next Steps on Sespe Creek Levee Ventura County Watershed Protection District reaches consensus with FEMA and Army Corps of Engineers on the retrofit work necessary to restore Q-100 capacity. Prepare Environmental Impact Report, Plans and Specifications. Locate funds and construct improvements. Obtain Letter of Map Revision from FEMA which removes Flood Zone “A” and requirements for flood insurance. Accreditation: 3 to 10 years ALL CONCEPTS AND COSTS PRESENTED TONIGHT ARE PRELIMINARY AND SUBJECT TO SIGNIFICANT CHANGE T E C H N I C A L S T U D I E S 15

  15. Heritage Levee Issues • LOMR going to FEMA this month: October 2009. • If approved by FEMA, Heritage area could be removed from Flood Zone “A” as early as Spring 2010. • Accreditation: 6 months to 6 years Heritage Levee (City)

  16. Pole Creek Debris Basin Issues • Construction of permanent basin on hold until Heritage Bridges project moves forward. • Once approved by FEMA El Dorado should be removed from Flood Zone “A” • Accreditation: 4 to 10 years Pole Crk Debris Basin (WPD)

  17. Pole Creek Channel Issues • VCWPD is planning to increase capacity from Q-50 to Q-100. • Schedule and funding for this work is uncertain due to issues over Steelhead Trout passage. • Accreditation: 5 to 15 years • Next FEMA map update (2012) may put some homes in east Fillmore into Flood Zone “A” until channel improvements are complete. Pole Crk Channel (wpd)

  18. QUESTIONS ? Accredited: Non Accredited: Pole Crk Channel (wpd) Pole Crk Debris Basin (WPD) Heritage Levee (City)

  19. Levee Certification Websitehttp://www.vcwatershed.org/levee

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