Transcript Delta Flood Protection Program

Delta Risk Management Strategy
US Army Corps
of Engineers
SCWC/SCWD MEETING
JUNE 27, 2007
Delta-Suisun Marsh Branch
Department of Water Resources
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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
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DRMS
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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
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DRMS
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AB 1200 Continued (CWC 139.4)
– DWR/DFG to Determine Principal Options for Delta
– DWR to comparatively rate for ability to:
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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
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DRMS
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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)
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DRMS
DRMS Technical Memoranda
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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
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DRMS
Phase 1
• Based on Business-As-Usual Assumptions
• Development of a Risk Analysis to Evaluate the
Impact to Delta Levees from:
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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
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Summary of Key Findings from
Phase 1 (preliminary)
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160-260 flood-related island failures
expected in the next 100 years
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12-15 simultaneous island failures in
a major flood event
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15- 30% chance of 30+ islands failing
simultaneously in a major earthquake
in the next 25 years
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Summary of Key Findings (continued)
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Probability of flood-related levee failure
– increases by 10% in 2050
– Increases by 20% in 2100
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Probability of seismic-related levee failure
– increases by 12% in 2050
– increases by 27% in 2100
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3 feet of sea level rise would push the salt
line about 3 miles to the east
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DRMS
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Phase 2
Development of Risk Reduction/Risk Management
Strategies for Long-Term Management of Delta
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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”
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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
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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
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DRMS Phase 2
Trial Scenarios Being Proposed
Improved Levees
Armored Pathway
Isolated Conveyance
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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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