Daylight: A key element in restoring and illuminating Elliott Bay’s nearshore ecosystem

In the early 1900s, Seattle began to expand the natural shoreline westward into Elliott Bay to accommodate ships that came to port at the deep water piers along the central waterfront. The mudflats and gently sloping beaches of Seattle’s original waterfront made way for concrete, steel, and piers. Because of these changes, the juvenile salmon that migrate through Elliott Bay are left with little light and limited shallow water habitat along the shoreline.

 

The historic shoreline is filled during construction of the existing seawall

The historic shoreline is filled during construction of the existing seawall

The Seawall Project will include habitat improvements along the new seawall. New light penetrating surfaces, in the form of glass blocks in the overhanging sidewalk, will help light reach the water near the seawall and minimize the light to dark contrast that overwater structures create. Ensuring sunlight can reach the water is important for encouraging habitat growth and lighting the way for migrating salmon.

 

The Seawall Project has partnered with the University of Washington to measure existing light levels near the seawall and study salmon behavior, and the project has determined the best pattern to filter light to the water below while still providing structural integrity.

The new sidewalk will include light penetrating surfaces in a checkered pattern

The new sidewalk will include light penetrating surfaces in a checkered pattern

 

The first light penetrating surface panels have been cast – one of several “pre-cast elements” of the project – and will be installed in the work zone south of Colman Dock at the end of the year. When construction is complete in 2016, theses panels will provide a continuous lighted corridor along the central waterfront for migrating juvenile salmon and other sea life.

 

Glass blocks in the overhanging sidewalk help light reach the habitat below

Glass blocks in the overhanging sidewalk help light reach the habitat below

For more information about seawall construction, visit the Seawall Project website. If you have questions, email the Seawall Project (seawall@waterfrontseattle.org) or call the 24-hour hotline (206.618.8584).