UW News

August 5, 2010

Archaeology crews examine Arboretum locations for future bridge supports

Crews working for the Washington State Department of Transportation began fieldwork in the Washington Park Arboretum Aug. 3 to continue studying locations where support columns will be built for a new SR 520 bridge.


The department recently identified its preferred alternative for the SR 520 I-5 to Medina Bridge Replacement and HOV Project, which proposes to replace the aging and vulnerable floating bridge and improve transit and HOV reliability in the corridor by building a six-lane road and reconstructing the Seattle interchange.


“We’ve selected a preferred alternative that minimizes the effects of a new SR 520 bridge over Foster Island,” said SR 520 Program Director Julie Meredith. “Now we are working to confirm that there are no archaeological resources in the locations where future pilings and columns are planned for the SR 520 bridge.”


State and federal law requires the department to analyze areas where a project could potentially affect archaeological resources. With the input of area tribes, preliminary designs were drafted for a new SR 520 bridge that minimize potential effects on Foster Island. With those designs in hand, the department now can conduct detailed field analysis in the areas that will be needed for bridge supports.


Professional archaeologists plan to use hand tools to investigate areas on Foster Island where there are plans to construct temporary bridge supports and permanent support columns for a new SR 520 bridge. This fieldwork is expected to take approximately 75 days, through mid-October.


A field team will work approximately 10 hours per day in 10-day shifts. When the field investigations are complete, all work areas will be returned to their pre-investigation appearance in coordination with the Washington Park Arboretum.


The department works in consultation with regional Native American tribes, the state Department of Archaeology and Historic Preservation, the state historic preservation officer, and the Advisory Council on Historic Preservation.


The fieldwork results will inform the final environmental impact statement. Construction on a new floating bridge is scheduled to begin in 2012, and a new floating bridge is scheduled to open to traffic in 2014.


For more information about the SR 520 Bridge Replacement and HOV Program and the fieldwork, click here.