The Measure
Delta levees reduce the flood-related risk to people, property, and state interests in the Delta.
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Expectations
Levees in the Delta will be improved over time to reduce the risk to people, property, and state interests in the Delta.
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Performance Metrics
- Percentage of urban communities in the Delta protected by levees meeting DWR’s urban level of flood protection criteria.
- Percentage of rural Delta islands and tracts protected by levees at or above the Bulletin 192-82/PL 84-99 standard.
Next Data Update: DWR is producing new levee data using 2017 LIDAR data, anticipated by the end of 2021.
The Delta is an inherently flood-prone area. Historically before the Delta was modified with levees and other human structures, the Delta’s low-lying islands and floodplains overflowed with rivers' natural flows for long periods each spring. Today, levees within the legal Delta protect approximately 740,000 acres of land. Many Delta levees protect land below sea level, they hold back water all day, year-round, rather than only during floods, and are called "the hardest working levees in America” (Delta Plan 2013).
Reducing flood risks to people, property, and state interests is critically important in the Delta and levees play a major role in flood-related risk reduction. State and federal guidelines and criteria establish minimum criteria for levee design and maintenance. The Public Law 84-99 (PL 84-99) standard is a minimum requirement established by U.S. Army Corps of Engineers (USACE). USACE developed a Delta-specific standard based on the Delta particular organic soils and levee foundation conditions.
Levees in the Delta will be improved over time to reduce the flood-related risk to people, property, and state interests in the Delta. This measure tracks the quality of Delta levees against predominant levee standards.
Each chapter of the Delta plan includes strategies to achieve the goals of the plan. These strategies are general guidance on achieving the objective laid out in the plan and in the Delta Reform Act of 2009. Associated with these strategies are recommendations. Strategies may also have associated performance measures. Delta Plan performance measures track progress in achieving desired outcomes for the Delta Plan. Below is the strategies associated with this performance measure.
Delta Plan Strategy
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Prioritize Investment in Delta Flood Management
Metric
- Percentage of urban communities in the Delta protected by levees meeting Department of Water Resources (DWR) urban level of flood protection criteria. This will be evaluated at least every five years.
- Percentage of rural Delta islands and tracts protected by levees at or above the Bulletin 192-82/PL 84-99 standard. This will be evaluated at least every five years.
Baseline
- Percent of urban area in the Delta protected by levees, meeting DWR’s urban level of flood protection criteria, as of completion of the Delta Levees Investment Strategy.
- Percentage of rural Delta islands and tracts protected by levees at or above the Bulletin 192-82/PL 84-99 standard, as of completion of the Delta Levees Investment Strategy.
Target
- 100 percent of urban communities in the Delta are protected by levees meeting DWR’s urban level of protection criteria, demonstrated by 2025.
- 100 percent of rural Delta islands and tracts are protected by levees at or above the Bulletin 192-82/PL 84-99 standard, demonstrated by 2050.
Data Source
Data is from the Delta Levee Investment Strategy (DLIS)
Spatial data of the Delta levees
Delta Levee Investment Strategy
MyHazards from the California Office of Emergency Services
The Delta Levees Maintenance Subventions Program from the Department of Water Resources