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Delta Risk Management Strategy

Delta Risk Management Strategy. SCWC/SCWD MEETING JUNE 27, 2007. Delta-Suisun Marsh Branch Department of Water Resources. DRMS. Development of DRMS 2000 CALFED ROD Called for Risk Assessment of Delta Levees 2005 – Levee Risk Analysis Team Did Preliminary Work – Seismic only

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Delta Risk Management Strategy

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  1. Delta Risk Management Strategy SCWC/SCWD MEETING JUNE 27, 2007 Delta-Suisun Marsh Branch Department of Water Resources

  2. DRMS Development of DRMS • 2000 CALFED ROD Called for Risk Assessment of Delta Levees • 2005 – Levee Risk Analysis Team • Did Preliminary Work – Seismic only • Also Developed Project Scope for DRMS • 2005 – AB 1200 Enacted • 2006- Governor’s Executive Order- Delta Vision

  3. DRMS • AB 1200 (CWC 139.2) Sets General Framework for DRSM • DWR Shall Evaluate Potential Impacts on 50, 100, 200-year projections on possible impacts to Delta from: • Subsidence • Earthquakes • Floods • Climate Change • & Combination of above

  4. DRMS • AB 1200 Continued (CWC 139.4) • DWR/DFG to Determine Principal Options for Delta – DWR to comparatively rate for ability to: • Prevent Disruption of Water Supplies Derived from Delta • Improve the Quality of Water Supplies Derived from Delta • Reduce Salts, Maintain Water Quality • Preserve, Protect, Improve Delta Levees • Protect Water Rights/Environments of River Systems • Protect Infrastructure within Delta • DFG shall rate all options for its ability to restore salmon & other fisheries that use the Delta • Report Due – January 2008

  5. DRMS • Contract Information • URS Corporation, Oakland, CA • Over 20 subcontractors • Approved by DGS - March 6, 2006 • 3-year contract • Includes a new LiDAR aerial survey of Delta • Guidance to URS – No new studies, use best available info, however, some limited exclusions: • Subsidence; Seismic hazard • DRMS report has several new models of Delta operations (i.e., Risk, Hydrodynamics, ER&R, Water Analysis)

  6. DRMS DRMS Technical Memoranda • Risk Analysis • Seismology (PSHA) • Ecological Impacts (Ecosystem) • Subsidence • Levee Vulnerability • Flood Hazard • Wind Wave Analysis • Climate Change • Water Analysis Module (Hydrodynamics) • Geomorphology • Impact to Infrastructure • Economic Consequences • Emergency Response & Repair

  7. DRMS Phase 1 • Based on Business-As-Usual Assumptions • Development of a Risk Analysis to Evaluate the Impact to Delta Levees from: • Floods • Earthquakes • Subsidence • Normal Conditions • Climate Change • Determine Consequences to Economy & Eco-System based on Risks Found • Draft Risk Analysis Report submitted April 23 ’07 • Public Draft July 2007 • Independent Review by CALFED – July – August ‘07

  8. Summary of Key Findings from Phase 1 (preliminary) • 160-260 flood-related island failures expected in the next 100 years • 12-15 simultaneous island failures in a major flood event • 15- 30% chance of 30+ islands failing simultaneously in a major earthquake in the next 25 years

  9. Summary of Key Findings (continued) • Probability of flood-related levee failure • increases by 10% in 2050 • Increases by 20% in 2100 • Probability of seismic-related levee failure • increases by 12% in 2050 • increases by 27% in 2100 • 3 feet of sea level rise would push the salt line about 3 miles to the east

  10. DRMS Phase 2 • Development of Risk Reduction/Risk Management Strategies for Long-Term Management of Delta • Draft Final Report Due August ’07 • Public Review Draft – Oct ’07 • Independent Review by CALFED – Oct – Nov ’07 • DRMS Final Report – November 2007 • Includes Recommendations for Future Work/Studies in the Delta • Will be provided to Delta Vision Blue Ribbon Task Force for Consideration in the “Vision for the Delta”

  11. Delta Risk Management Strategy Phase 2: Development and Evaluation of Risk Reduction Strategies Develop a menu of risk reduction measures that could reduce risk – “building blocks” Package the measures into different combinations -> “trial scenarios” Use Risk Model to evaluate potential risk reductions Evaluate benefits and costs of risk reduction measures

  12. Delta Risk Management Strategy Potential Risk Reduction Building Blocks: • Improved Levee Maintenance • Upgraded Delta & Urban Levees • Enhanced Emergency Preparedness/Response • Pre-Flooding of Selected Western Islands • Land Use Changes to Reduce Subsidence • Armored Through Delta “Pathway” Conveyance • Isolated Conveyance • Elevation of State Highways on Piers • Armored Infrastructure Corridor • San Joaquin By-Pass • Suisun Marsh Restoration • Cache Slough Restoration • Fish Screens • Reduced Water Exports

  13. DRMS Phase 2 Trial Scenarios Being Proposed • Improved Levees • Armored Pathway • Isolated Conveyance

  14. Thank You For more information on the DMRS work, please see the DRMS web site at: http://www.drms.water.ca.gov/

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