Keeping California's Coast Accessible

Protecting Public Trust lands and uses as sea levels rise

Public Trust

Resources and uses

A legal principle called the  Public Trust Doctrine  establishes that certain lands are held in trust by the state for the benefit and use of all people.

On the coast, Public Trust lands are generally located on lands submerged by the sea and on tidelands – lands covered and uncovered by the ebb and flow of the tides. Adjacent to tidelands, many sandy beaches are also owned by public agencies like State Parks.

Public Trust uses include water-related commerce, navigation, fishing, bathing, swimming, and boating, as well as other recreational uses, public access, and preservation of lands for scientific study and as open space and wildlife habitat.

Nearly one quarter of the California coastline is managed by State Parks — with 111 oceanfront park units and an additional 17 park units within the coastal zone, supporting the recreational economy and a diversity of wildlife and habitat (Photo credit: Montaña de Oro State Park)


The following map tour shows many of the different types of resources and public uses protected by, or that do not interfere with, the  Public Trust Doctrine .

Impacts

What could impact or change our current Public Trust lands and uses?

 High tide flooding  in San Francisco, San Mateo, Half Moon Bay, Cabrillo Beach, and Oceanside, respectively, demonstrate how sea level rise might impact these locations with more frequency in the future (Photo credits:  California King Tides Project ).

Public Trust lands on the coast generally correspond to areas seaward of the mean high tide line (Graphic by Jeremy Smith)

What can stop you from taking a walk on the beach, or even getting there in the first place? Seawalls, flooded parking lots, and closed pathways are just a handful of barriers that sea level rise will make harder to avoid.

Sea level rise will shift Public Trust tidelands toward the shore and increase the extent of flooding inland (Photo credit: Charles Lester)

The effects of coastal squeeze (Graphic by Jeremy Smith)

Public beaches and tidelands enjoyed by Californians and visitors are changing due to impacts from sea level rise and other coastal hazards. Where protective structures like seawalls temporarily fix the shoreline, trapping beaches between land and sea, what is known as “coastal squeeze” occurs. These protective structures trap sand behind them that would have otherwise been added to the beach from bluff erosion. Loss of beach, and often coastal access, occurs as a result.

If habitats such as beaches, dunes, and wetlands are located along a natural, unarmored shoreline, they can often shift inland as sea levels rise. This is not the case for over 120 miles of California's outer coast, which now has some type of seawall or armoring. Shoreline armoring and development that may have originally been located upland, or only slightly on tidelands, will have increasing impacts on public tidelands as the sea rises.


When Public Trust lands are impacted by development, some public uses are threatened as well.  Here are some examples:

What can be done?

California’s state agencies, local governments, property owners, and other stakeholders have begun working together on sea level rise adaptation strategies. The following examples explain local challenges and demonstrate efforts to protect our access to Public Trust lands and waters.


Next Steps

State and local agencies (Coastal Commission, State Lands Commission, cities and counties) will continue to coordinate their efforts to evaluate and respond to Public Trust impacts, including:

  • Developing maps and tools to assist with tideland boundaries
  • Promoting specific policies in land use plans to protect Public Trust resources and considering how beaches and other Public Trust resources will change as sea level rises
  • Encouraging the use of nature-based solutions as alternatives to hard armoring
  • Rejecting or placing conditions on proposed developments or uses that will foreseeably cause harm to Public Trust resources and uses
  • Working together towards neighborhood or regional scale adaptation projects

Interested members of the public and stakeholders should participate in local planning and project decision-making


Resources

 The Public Trust Doctrine: A Guiding Principle for Governing California’s Coast Under Climate Change  (Center for Ocean Solutions 2017): a consensus statement by the Center for Ocean Solutions and public trust and coastal land use experts on California’s duties under the Public Trust Doctrine and opportunities to improve coastal governance and management


Acknowledgements

This story map was developed using federal financial assistance provided by the Coastal Zone Management Act, as amended, under award NA20NOS4190101, administered by the Office for Coastal Management, National Oceanic and Atmospheric Administration, U.S. Department of Commerce. The statements, findings, conclusions, and recommendations are those of the author and do not necessarily reflect the views of the National Oceanic and Atmospheric Administration or the U.S. Department of Commerce.

Nearly one quarter of the California coastline is managed by State Parks — with 111 oceanfront park units and an additional 17 park units within the coastal zone, supporting the recreational economy and a diversity of wildlife and habitat (Photo credit: Montaña de Oro State Park)

Public Trust lands on the coast generally correspond to areas seaward of the mean high tide line (Graphic by Jeremy Smith)

Sea level rise will shift Public Trust tidelands toward the shore and increase the extent of flooding inland (Photo credit: Charles Lester)

The effects of coastal squeeze (Graphic by Jeremy Smith)