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The Alaskan Way Seawall: The Facts  What’s New Seawall Rehabilitation SDOT will replace the deteriorated wood facing (Ekki wood) on the seawall between Piers 69 and 70. Specifically this work consists of removing the deteriorated timber, releasing clean pea gravel between the Ekki wood facing and the sheet pile, and patching the original sheet pile structure where holes are present. The rehabilitation work is scheduled to be complete, weather permitting, by March 2008. Seawall Scientific Habitat Enhancement Study Habitat Test Panels will be installed at three locations on the seawall. This work is part of the collaborative scientific research between SDOT and the University of Washington. This study will help to determine what shapes and textures will best serve the marine habitat of Puget Sound. The results will help inform the final design of the seawall face. 18 panels will be installed along the seawall with six at each of the three locations – at Clay Street, Vine Street, and between Pier 62 and the Seattle Aquarium. In addition to the panel installation, “troughs” will be created that extend out from the face of the seawall. The intent of the trough is to mimic shallow water sediment habitats that have largely been lost along the Seattle shoreline. The potential benefits could include higher production of marine life and trapping additional sediment and organic matter. The University of Washington will sample for marine life in the area over a two year period to measure the effectiveness of the habitat panels and troughs. Once a long-term solution has been determined for the central waterfront of the Viaduct replacement, SDOT intends to use the findings of this study to build a seawall that will improve the ecological function of the seawall and sustain marine life. See the November Construction Notice For information on the Seawall Rehabilitation and Habitat Research Project contact either of the following: John Arnesen, Project Manager at 206-684-8921 or john.arnesen@seattle.gov Katherine Bush, Communications Office at 206-233-1084 or katherine.bush@seattle.gov Related Initiatives
A History
What's at Risk?
The Significance of the Seawall
Army Corps of Engineers Involvement Seattle has requested that the U.S. Army Corps of Engineers help replace the seawall. The Corps provides assistance in solving water resource problems that are beyond the capabilities of local governments, due to financial constraints, lack of technical expertise or jurisdictional boundaries. The Corps is conducting an environmental study to accompany a feasibility study to determine its involvement. What Now? The city of Seattle continues to monitor and provide temporary repairs. They also recently unveiled a new "Gribble Camera" that allows them to easily monitor underwater damage to the seawall. For more information on the seawall contact John Buswell, Structure Engineering Supervisor, at 206.684.5301 or email John.Buswell@Seattle.gov.  |
The second vulnerability is significant damage to the timber platform
from a variety of marine borers called Gribbles and Toredos.
Found in multiple locations, the damage means that the seawall's vulnerability
to an earthquake is greater than previously thought. Even without an earthquake,
there will be serious consequences as a result of continued deterioration.
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