COASTAL EXPOSURE

The InVEST Hazard Index was used to map California's coastal exposure to hazards at 250-meter segments, specifically erosion and inundation during storm events and sea level rise to year:2050. The index also accounts for biodiversity's individual and combined role in buffering wave energy, called "Habitat Role".

  CLIMATE ADAPTATION STRATEGIES

** Click on strategy name to download policy brief** 1. ENGINEERED

• Beach Nourishment: Artificial placing of sand on a beach to replace eroded sand or to protect against future erosion
• Cliff Stabilization: Engineered project to decrease or limit erosion of cliff faces to maintain the cliff in its present location
• Dune Restoration Project: Engineered project to enhance or restore vulnerable or eroded dune systems
• Living Shorelines: Restoration utilizing plants or other natural elements sometimes in combination with harder shoreline structures to decrease wave impacts
• Riprap: Large rocks and boulders placed on shoreline to buffer against erosion and waves
• Seawalls Structure parallel to shoreline; engineered to protect against encroaching seas
• Elevation of Structures: Engineered solution where a structure is raised in response to a current or expected flooding hazard
• Wetland Restoration: Restoration effort allowing tidal wetlands to recover in areas that have been diked or otherwise altered from their original conditions

2. FINANCIAL

• Buyout Program Government tool to acquire properties
• Conservation Easements: Agreements not to develop property in exchange for money or tax incentives
• Geologic Hazard Abatement Districts: Special district formed to prevent, mitigate, abate or control some geologic hazard
• Transfer of Development Rights: Tradable development credit program where development rights are severed from sending areas and transferred to receiving areas

3. LEGAL AND REGULATORY

• Development Moratoria: Temporary development prohibition while planning proceeds
• Overlay Zones: Additional set of zoning restrictions that overlay original zoning of area
• Redevelopment Restrictions: Building code amendments to limit the redevelopment allowed in a certain location
• Trigger Language: Planning framework whereby an observed event “triggers” a shift to implementing specific adaptation policies

OTHER PROPOSED TOPICS

• Public Trust Doctrine (PTD): Investigation of PTDs role in SLR adaptation planning
• Takings Concerns: Distillation of current case law regarding takings claims in California

Sea level rise:

A one-foot rise in sea level projected for year 2050, relative to year 2000 sea levels,would be appropriate for modeling the exposure assessment and habitat protective role assessment.

We considered the National Research Council 2012 Report's projections for San Francisco of an 11-inch rise in mean sea level by 2050 (Table 5.3, page 117) and the Rising Seas in California: Update on Sea-Level Rise Science 2017 report’s summary of a 67% probability that the sea level rises between 0.6–1.1 feetby 2050 (Table 1, page 26) to determine this value and timeline.

These figures agree with the coastal planning community's approach to incorporating the upper limits of a 30-year timeline of predicted rising sea levels as well as Step One of the California Coastal Commission Sea Level Rise Guidance on addressing sea level rise in Local Coastal Programs.

We used NOAA tide gauges for xx counties to allocate net SLR through 2050 based on zones. The map to the left shows how they were allocated in the model and in our visualizations for Coastal Exposure: Hazard Index.

  DRIVERS OF EXPOSURE

• Six biophysical variables were ranked from 1-5 statewide.
• Coastal segments ranked 4 or 5 drive highest hazard index scores.
• Ranking for relief and wave exposure variables varies at county scale.