About the Puget Sound Institute

2015 Puget Sound Factbook Book | v3.0
breakwaters/jetties, overwater structures, roads within 25 m of the shoreline, active &
inactive railroads within 25 m of the shoreline.
a. Only 31.3% of the length of Puget Sound’s shoreline has not been modified (i.e.,
none of the stressors occurs) (Fresh et al., 2011).
b. Negligible historically, artificial shoreline now represents about 9.5% of the
shoreline (Fresh et al., 2011).
4. Armoring is clearly the most frequently occurring stressor, observed in along 74–78% of
shoreline segments studied (Fresh et al., 2011), followed by nearshore fill (62%) and
overwater structures (30%) (Schlenger et al., 2011).
a. Armoring occurs along 27% of the length of the shoreline (1070 of 3969 km)
(Schlenger et al., 2011).
b. The percent of armored shoreline varies considerably (10 to 63 percent) across
the sub-basins in the study area (Schlenger et al., 2011).
5. An estimated 34.6% of shorelines lack natural vegetation (Simenstad et al., 2011).
a. Riparian vegetation overhanging the intertidal zone occurs along only 440 miles
of the shoreline of Puget Sound (Clancy et al., 2009).
b. Loss of overhanging vegetation can alter the microclimate of beaches for
incubating eggs of intertidal spawning fish (Rice, 2006).
c. Loss of vegetation reduces the supply of terrestrial insects falling into nearshore
waters, an important food source for migrating juvenile salmonids (Brennan &
Culverwell, 2004).
6. Fragmentation of nearshore marine habitat by frequent separate smaller anthropogenic
shoreline alterations can reduce biological productivity beyond the effects of fewer but
larger alterations (Gaydos et al., 2009).
7. The South Central Puget Sound sub-basin is the most impacted sub-basin in the Puget
Sound Basin, with 51% of the nearshore zone area developed (Schlenger et al., 2011).
a. Only 1% of the shoreline segments in this sub-basin had not been modified (Fresh
et al., 2011).
b. The Hood Canal sub-basin is the least impacted, with 10 percent of the nearshore
zone area developed (Schlenger et al., 2011).
8. Projections suggest that approximately 19 % of nearshore segments studied in Puget
Sound will become more degraded in the future (Schlenger et al., 2011). The segments
forecast to degrade comprise 20 % of the shoreline length.
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