Coastal Zone Management

On May 8, 2018, the City of Encinitas Sea Level Rise Subcommittee hosted a public workshop to provide information about coastal erosion and sea level rise in Encinitas.  At the meeting, a panel of six renowned guest speakers presented on topics such as current research on coastal processes, bluff mapping, flooding mapping and coastal resilience to sea level rise. Click below to view the presentations from the meeting:

Kathy Weldon’s Presentation
Crystal Najera’s Presentation
Laura Engeman’s Presentation
Bob Guza’s Presentation
Adam Young’s Presentation
Darryl Hatheway’s Presentation

 

Preparing for Sea Level Rise

Global sea level rise has been rising over the past century, and the rate has increased in recent decades.  In 2014, global sea level was 2.6 inches above the 1993 average – the highest annual average in the satellite records (1993-present).  Sea level continues to rise at a rate of about one-eighth of an inch per year. 

Higher sea levels mean that destructive storm surges push father inland than they once did, which also means more frequent nuisance flooding.  This is cause for concern along Coast Highway 101 and the Cardiff State Beach area. 

The two major causes of global sea level rise are thermal expansion caused by warming of the ocean (since water expands as it warms) and increased melting of land-based ice, such as glaciers and ice sheets.  The oceans are absorbing more than 90 percent of the increased atmospheric heat associated with emissions from human activity. 

Sea level rise at specific locations may be more or less than the global average due to local factors such as land subsidence from natural processes and withdrawal of groundwater and fossil fuels and changes in regional ocean currents.  Sea level for Southern California is measured using tide stations and satellite laser altimeters at Coastal Data Information Program (CDIP) managed by the Scripps Institution of Oceanography at CDIP Homepage.

Coastal Commission Sea Level Rise Guidance

The California Coastal Commission unanimously approved the Sea Level Rise Policy Guidance Document on August 12, 2015.  The document is designed to prepare for the impacts of sea level rise to ensure a resilient coast for present and future generations.  The document focuses on how to apply the Coastal Act due the challenges presented by sea level rise through Local Coastal Programs (LCP) certifications and updates and Coastal Development Permit (CDP) decisions.    Based on the guidance document the CCC started to require sea level rise analysis on the following Capital Improvement Projects: Beacon Beach Rehabilitation Project, Moonlight Beach Marine Safety Tower and the Coast Highway 101 Sewer Pump Station. 

FEMA Mapping

The Federal Emergency Management Agency (FEMA) is currently performing detailed coastal engineering analysis and mapping of the Pacific Coast of California.  Results will be used to re-map the coastal flood risk and wave hazards for California coastline.  Key coastal processes such as dune erosion, wave setup, wave run-up, overtopping, overland wave propagation and evaluation of coastal structures are accounted for in determining new Base Flood Elevations (BFE). 

The coastal flooding risk analyses include determining:  coastal stillwater elevations(SWEL), wave setup, wave run-up, overtopping extent, storm-induced erosion, overland wave propagation, and impacts to coastal structures.  Total wave levels will be determined for 50-,20-,10-,4-,2-,1-, and 0.2 percent annual chance flood events based on extreme value analysis of a 50-year wave and water level hindcast.  These analyses will be used to establish and/or revise the Special Flood Hazard Area (SFHA), Base Flood Elevation (BFE), and hazard zones for coastal floodplain mapping.  The new flood data and mapping will be used for updating and revising the Flood Insurance Study (FIS) and Flood Insurance Rate Maps (FIRMs).

Vulnerability Assessment and Adaptation Planning Grant (ICLEI)

The San Diego Foundation has funded ICLEI to evaluate sea level rise risks, vulnerabilities and adaptation strategies for the cities of Encinitas, Oceanside and San Diego.  ICLEI will provide a planning document on potential impacts due to flooding and possible inundation in 2100.  ICLEI will evaluate the infrastructures that will experience flooding during extreme events and develop adaptation planning tools for the City to consider.

Resilience refers to the ability to endure impacts associated with sea level rise and to respond, recover, and adapt to consequences.  An area, site, facility, or project that is highly resilient will be able to accommodate or tolerate more frequent flooding and adverse consequences associated with increasing sea level rise. Risk refers to the potential for, or exposure to, loss or undesirable impacts (or outcomes) and can be characterized as the combination of probability and consequence.  In other words, the lower the likelihood and effects, the lower the risk.  Facilities such as transportation facilities may have lower adaptive capacity and higher risk.  Ultimately, the scenario selected for a plan, project site, or design should reflect how much risk can be tolerated and the ability and effort necessary to implement modifications if adverse conditions are encountered in the future.

Adaptation Strategy Development Grant (NOAA)


The San Diego Climate Collaborative has also received a grant from NOAA (National Oceanic and Atmospheric Administration) to coordinate the coastal communities of Oceanside, Carlsbad, Encinitas, Del Mar and San Diego to provide new data on flood mapping, develop additional legal, economic and scientific expertise and help cities with outreach and communication.

Cardiff Beach Living Shoreline Project – Dune Restoration Project

 

Cardiff Beach Living Shoreline Project – Dune Restoration Project

July 2016 - The City of Encinitas, in partnership with the San Elijo Lagoon Conservancy, the California State Coastal Conservancy, and the California State Parks, proposes to create a dune system on the seaward side of Highway 101 on Cardiff State Beach to serve as a natural sea level rise (SLR) adaptation approach to protect a vulnerable segment of the roadway while providing native dune habitat. 

Coastal dune systems have been found to provide multiple benefits by providing coastal habitat and storm damage reduction during extreme events.  The Cardiff Beach Living Shoreline Project proposes to beneficially re-use export materials generated from the San Elijo Lagoon Restoration Project or other opportunistic sources of sand for the dune construction.  The project is scheduled to begin in winter 2017. 

The Proposed Project area spans 2,900 linear feet (about 0.5 mile) of shoreline, from the Chart House Restaurant to the north to just before the South Cardiff State Beach Parking Lot to the south. 

The State Coastal Conservancy and the Ocean Protection Council have provided the grants funds to provide an adaptation measure to reduce the potential impacts due to sea level rise while providing a multi-benefit of improving the native dune habitat.