Coastal Regional Sediment Management Plan for Monterey Bay, California - Protection of Highway 1

This Coastal Regional Sediment Management Plan identifies four strategies to reduce coastal erosion along southern Monterey Bay in California. One of these strategies involves beach nourishment to protect critical infrastructure, including sections of California Highway 1.

The southern Monterey Bay shoreline is primarily composed of wide sandy beaches backed by sand dunes that span up to 5 miles wide and 150 feet high. The majority of this shoreline is eroding rapidly, at rates of 1-6 feet per year. The region is heavily developed, with several oceanfront facilities at high risk due to this erosion. Sections of Highway 1, which runs very close to the shore at Sand City and near the Monterey Beach Resort, will be threatened within the next 50 years at the current rate of erosion.

To protect Highway 1, as well as other areas of critical infrastructure, the Plan recommends beach nourishment along the shoreline within the cities of Sand City, Seaside, and Monterey. Beach nourishment was chosen because this stretch of shoreline experiences relatively low wave energy and low rates of sediment transport, meaning that sand placed at the site will remain there for a longer period of time. In addition, the vulnerable facilities within this area are located close together, which concentrates the benefits of beach nourishment while minimizing environmental impact to the rest of Monterey Bay.

This Plan evaluates local coastal processes, including erosion rates, sediment transport rates, and projected sea-level rise. Based on climate change forecasts, projected sea-level rise will increase shoreline erosion along southern Monterey Bay. The Plan accounts for an average rise in sea level of 3 feet over the next century, a value that was aligned with rates recommended by the California Coastal Commission.

The Plan was initiated by the California Coastal Sediment Management Workgroup, which is a taskforce of state, federal and local entities that engage with regional stakeholder groups to create Regional Sediment Management (RSM) plans for specific portions of the California coast. The RSM plans are designed to identify and resolve issues of coastal erosion on a regional basis.  RSM plans from different regions will eventually be combined into a statewide master plan to guide regulatory and investment decisions. CSMW partnered with the Association of Monterey Bay Area Governments (AMBAG) to develop the first RSM Plan in 2008. The objective of this Plan is to provide policy recommendations on ways to reduce shoreline erosion and restore and maintain coastal beaches along southern Monterey Bay. The recommendations are meant to inform local decision-making.

Funding for the Plan was provided by the California Department of Boating and Waterways, on behalf of CSMW. Additional technical support was provided by the Southern Monterey Bay Coastal Erosion Workgroup, which is largely driven by the Monterey Bay National Marine Sanctuary.

The Plan would be implemented by AMBAG as a Joint Powers Authority, which is an institution that allows two or more public authorities to operate collectively. This approach was chosen because coastal erosion issues are regional in nature, and transcend the boundaries of existing public authorities. AMBAG would act as the lead planning and coordinating agency, with responsibilities that include seeking funds, administering studies, completing environmental documentation, and acquiring permits. AMBAG would also consult with local decision-makers with regard to their land-use authority.

At this time, AMBAG is still in the planning phase for implementing the beach nourishment project. The project is estimated to cost between $1 and $11 million, and would most likely be funded by a combination of federal, state, and local sources.

 

This Adaptation Clearinghouse entry was prepared with support from the Federal Highway Administration. This entry was last updated on December 29, 2014.

Publication Date: November 2008

Related Organizations:

  • Association of Monterey Bay Area Governments
  • California Coastal Sediment Management Workgroup

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  • Plans (other)

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