Over the past decade, levee maintenance and improvement activities have focused on raising levee heights, achieving modern flood protection standards, and improving levee stability. While progress has been made in maintaining and improving Delta Levees, much remains to be done. Despite ongoing improvements to urban and rural levees, less than 30% of Delta islands and tracts are fully protected by levees, meeting the applicable state or federal levee design standards. Despite this, flood risk decreased significantly between 2007 and 2017 due to a combination of levee improvements, new elevation data, and updated calculations concerning the probability of flooding.
The following Reduced Risk report card was developed as part of the Delta Plan Review that used the established performance measures to rate progress in implementing the Delta Plan over the past ten year (2013-2023). Read the 2024 Delta Plan Review full report to learn about additional review findings and the recommended actions that will inform Delta management priorities in next five years.
The overall performance measure score is rated “VERY GOOD” (76%-100% of target met) as of 2019 based on metric:
1. Percent of recommendations implemented by the Sacramento-San Joaquin Delta Multi-Hazard Coordination Task Force (Task Force). All (11) emergency preparedness and response recommendations from the 2012 Delta Multi-Hazard Task Force Report have been implemented.
View more: Multi-Hazard Coordination Task Force| Delta Stewardship Council (ca.gov)
The overall performance measure score is rated “VERY GOOD” (76%-100% of target met) as of 2022 based on the arithmetic mean of two metrics:
1. Expected Annual Fatalities (EAF) in the Delta.
2. Expected Annual Damages (EAD) in the Delta.
Flood risk decreased significantly between 2007 and 2017 due to a combination of levee improvements, new elevation data, and updated calculations concerning the probability of flooding. The updated risk projections in 2021 resulted in a greater than 50% reduction in both Estimated Annual Damages (EAD) and Estimated Annual Fatalities (EAF).
View more: Flood Casualties and Damages | Delta Stewardship Council (ca.gov)
The overall performance measure score is rated ‘FAIR” (26-50% of target achieved) as of 2023 based on two metrics:
1. Percentage of urban communities in the Delta protected by levees meeting Urban Standards: There were 0 urban island levee systems out of 6, or 0% that was reported to have 100% Department of Water Resources (DWR) urban level of flood protection criteria.
2. Percentage of Rural Delta islands and tracts protected by levees at or above rural standards: There were 21 rural island levees out of 69, or ~30%, reported to have 100% Bulletin 192-82 compliance.
View more: Delta Levees | Delta Stewardship Council (ca.gov)
The overall performance measure score is rated “VERY GOOD” (76%-100% of target met) as of 2023 based on metric:
1. Community Rating System credit points of Delta communities participating in the NFIP: Between 2013 and 2023, Delta communities participating in the NFIP increased their CRS scores by 4.3%.
The 4.3% growth rate for eligible Delta communities in 10 years exceeded the 1% target set to be reached by 2025.
View more: Flood Insurance Community Ratings | Delta Stewardship Council (ca.gov)