Research Technical Report

Coastal Erosion and Armoring in Southern Monterey Bay

Stamski, R. (June 2005)

Technical Report, Version 1.1, 68p.

INTRODUCTION

Development at the edge of California's highly erosive coast has led to increased pressure to protect both private and public infrastructure with various types of coastal protection structures, such as seawalls and revetments. The cumulative environmental impacts of this coastal armoring within the Monterey Bay National Marine Sanctuary (MBNMS; Figure 1.1) has been of growing concern, as they may interfere with the natural sediment dynamics, lead to the loss of public beaches, hinder public access to the coast, and have the potential to alter marine biological communities either during construction or via their long-term impacts (Stamski 2005).

In response to these concerns, the MBNMS is playing an increased role in the issue of coastal armoring as part of the congressionally-mandated update of its Management Plan. The sanctuary, in collaboration with other stakeholders, has developed an action plan with the goal of developing and implementing a proactive, regional approach to address coastal erosion and to minimize the negative impacts of coastal armoring on a sanctuary-wide basis.

As part of this action plan, the MBNMS has initiated a collaborative pilot effort with a number of partners to develop a regional planning approach that addresses the issue of coastal erosion and armoring in the southern Monterey Bay sub-region of the MBNMS, from the Salinas River mouth to Wharf #2 in Monterey. Participants in the Southern Monterey Bay Coastal Erosion and Armoring Workgroup include: representatives from the various local, state, and federal government agencies involved in studying and regulating these issues; scientific experts; and local decision makers.

The purpose of this report is to summarize scientific information on coastal erosion and armoring for southern Monterey Bay to support the sanctuary's Coastal Armoring Action Plan and the efforts of the Southern Monterey Bay Coastal Erosion and Armoring Workgroup as they consider effective ways to address this issue. This report provides background information on the geomorphic history of the area, summarizes the results of regional erosion studies, documents coastal development that may be threatened by erosion, and lays the groundwork for an investigation of alternatives to coastal armoring that are available in responding to coastal erosion.