Puget Sound Shorelines and the Impacts of Armoring: State of the Science

Problem Statement

Shoreline armoring – the construction of bulkheads and seawalls – has become a significant environmental issue on Puget Sound. Armoring influences beaches elsewhere on the shoreline, alters coastal ecology, and reduces the resilience of the coast to rising sea level. Shoreline planners and resource managers are demanding better information to guide decisions, evaluate impacts, and improve strategies for protecting and restoring degraded shorelines. Unfortunately, the science regarding coastal processes and armoring is limited, particularly as it applies to Puget Sound, where extensive eroding bluffs, mixed sand and gravel beaches, and a sheltered coastline present unique challenges distinct from many other coastal environments.

Workshop Objectives

This workshop convened regional and national experts to examine the state of the science relevant to shoreline armoring in environments similar to Puget Sound. Presentations addressed current understanding of Puget Sound, emerging scientific research on beaches and armoring, and relevant experience from other regions.

The objectives of the workshop included:

  • Summarize existing science relevant to coastal processes and armoring on Puget Sound
  • Improve understanding of the key geological processes and ecological linkages influenced by armoring
  • Identify major information and data needs, along with research strategies for addressing them
  • Develop guiding principles that will help managers make better decisions about shoreline armoring
  • Establish scientific foundation for future management workshops and guidance products


The workshop was limited to 35-40 people in order to maintain focus and to facilitate in-depth exploration. It included presentations and facilitated discussions. A field trip familiarized participants with Puget Sound shorelines and issues related to armoring, as well as provided time for informal interaction.


The Workshop Proceedings includes papers from each speaker and a synthesis of discussion sessions, including a summary of key findings and recommendations. The Proceedings also includes a literature review developed in conjunction with the workshop.  The USGS Scientific Investigations Report 2010-5254 entitled "Puget Sound Shoreline and the Impacts of Armoring – Proceedings of a State of the Science Workshop, May 2009" is available from the USGS at http://pubs.usgs.gov/sir/2010/5254/.