Archaeologists believe the shell deposits are the product of commercial shellfish activities carried out by early Seattleites around the turn of the 20th century, but more information will be obtained after a full laboratory analysis is completed. Still, after exercising due diligence, and following state and federal laws through coordination with the Department of Archaeology and Historic Preservation, tribes and King County, excavation was allowed to proceed.
No one wants to stop work. We understand and share the urgency of the public in wanting to resume tunneling as quickly and safely as possible. But we also have an obligation to follow state and federal laws, and exercise due diligence when dealing with potentially significant discoveries. That’s why we have a very prescriptive process in place for dealing with this type of incident. We’d like to extend our gratitude to DAHP, the tribes and King County for expediting their review so crews could resume excavation as quickly as possible.
Dealing with unanticipated discoveries
In the days since the shell deposits were unearthed, we’ve received quite a few questions about what laws govern the process for investigating unanticipated archaeological finds. If a potentially significant resource is discovered, WSDOT stops work to investigate, as required by state and federal laws. As part of the project’s federal approvals, WSDOT committed to an Unanticipated Discovery Plan. A standard condition for all WSDOT construction projects, this plan requires that potentially significant archaeological resources or deposits found during construction – basically, any potential archaeological materials that were not identified in pre-construction review – be evaluated.
Throughout the investigation, WSDOT archaeologists consult with DAHP and other stakeholders such as tribes and local governments to determine if the resource is culturally or historically significant. If it isn’t, work resumes. If it is, WSDOT looks at options to avoid the resource, minimize the effects to the resource, or mitigate for the effects to the resource.
In this case, all parties agreed that if the shell deposits prove to be significant from a regulatory perspective, the investigation we conducted, and the report we’re in the process of completing, constitutes sufficient mitigation. That is, our efforts to characterize the archaeology to date will provide a scientific and historical record of what was found that offsets the destruction of the deposits from excavation of the access pit.
Due to the potentially sensitive nature of the investigation, we temporarily disabled our access pit construction cameras on Oct. 28. We expect to have them back online soon so the public can watch Seattle Tunnel Partners crews as they work to get Bertha moving again. (UPDATE: As of Nov. 8, the access pit cameras are back online)
Oct. 28, 2014 update – Archaeological investigation begins at the access pit
Oct. 28, 2014 update – Access pit cameras temporarily disabled
Oct. 20, 2014 update – Access pit excavation is underway
Oct. 10, 2014 update – Seattle Tunnel Partners lowering groundwater near the access pit
Sept. 8, 2014 update – With pile work done, Bertha inches forward
Aug. 28, 2014 update – Construction of the access pit's underground walls wraps up, preparation for dewatering begins
Click here to see a full archive of progress updates