Bulkheads and seawalls along the shores of Puget Sound help ease erosion and stabilize bluffs to protect waterfront properties, according to the University of Washington.
But these walled structures also shrink beaches, reduce habitat for invertebrates and spawning fish and, indirectly, degrade conditions for iconic species like salmon and orcas.
Many studies have shown this pattern at seawall sites around Puget Sound.
A new University of Washington study shows that impacts at individual armored sites can scale up to have cumulative, large-scale effects on the characteristics of Salish Sea shorelines and the diversity of life they support.
It is the first study to analyze sites broadly within Puget Sound and offers the most comprehensive look to date at the impacts of shoreline armoring on the Salish Sea ecosystem.
When researchers looked at sites from south, central and north Puget Sound, the data showed that armored beaches became slightly narrower and steeper over time, and larger pebbles replaced finer-grained sediment and sand.
Additionally, in stretches of shoreline that were more heavily armored, even the unarmored areas showed similar impacts — less sand and more larger sediment on the beach.