July 12, 2001

From wood preservation to site remediation — the Cascade Pole cleanup

Landau Associates

Cascade Pole site
Photo courtesy of Landau Associates
A slurry wall has been installed at the Cascade Pole site in Olympia to help contain contaminated soil and groundwater.

Roots run deep in the Pacific Northwest — literally and figuratively. When the world thinks of Washington and the Northwest — they think Microsoft, Boeing, the Cascade Mountains, Puget Sound, orcas, salmon and trees. This seemingly endless natural resource enabled us to make a tremendous impact in production of wood-based products. Today, we have endangered species, growth management, diminishing resources, native growth protection, and a wood products industry that has come to recognize the face of change.

Environmental cleanup resulting from decades of wood preservation operations along the Olympia waterfront has been the focus for one local port authority since 1985 when the site came to the attention of the state Department of Ecology.

A parcel of upland and marine land owned by the Port of Olympia, that had been leased and used for wood treating operations since the 1930s by several operators, has another name today — the Cascade Pole Co. (CPC) cleanup site.

A long journey

The CPC site is undergoing remediation and the port hopes to have the sediment remediation work finished this year. Getting to this phase has been a long journey that has involved the community, owners, operators, lawyers, consultants, contractors, and state and federal regulatory agencies.

The port retained Landau Associates in 1987 to characterize the nature and extent of soil, sediment and groundwater contamination at the CPC site. These investigations revealed extensive contamination, including the presence of wood treatment chemicals, in the upland soil and groundwater and in the marine sediments adjacent to the site.

Subsequent to the initial investigations, Landau Associates assisted the port with development of a cleanup action plan in coordination with the Department of Ecology, design and construction of interim remedial actions to prevent the further release of contaminants to Budd Inlet, and (presently), design, permitting and remedial construction to cleanup the impacted sediments. All of these activities are being conducted under the Model Toxics Control Act, the state’s regulations that govern hazardous waste sites.

The contaminated sediments represent a threat to human health and the environment due to the potential exposure of marine life to the contaminated sediments and the subsequent potential for fish and shellfish to be collected for human consumption. But, before the sediments could be remediated, further releases of wood preservation chemicals from the upland portion of the site to Budd Inlet had to be stopped.

Interim remedies

Landau Associates assisted the port in design and construction of a series of interim remedies consisting of a slurry wall and expanded groundwater pump-and-treat system to contain contaminated soil and groundwater, site capping to minimize surface water infiltration, and an upland containment cell to store the contaminated sediments that will be dredged this summer.

These actions have also allowed over half of the site to be returned to productive use for log sorting and cargo handling activities. The remainder of the upland site area will serve dual purposes, providing for permanent containment of the dredged contaminated sediments, along with mixed marina and public access uses.

Sediment remediation for the Cascade Pole site requires the removal of 32,000 cubic yards of contaminated sediment, and presents some unique technical challenges.

First, sediment remediation requires the removal of highly contaminated sediments adjacent to the former wood treatment site. Remediation of the sediments has the potential to cause releases to Budd Inlet. This issue will be addressed by the first full-scale environmental application of the Gunderboom containment system in the Northwest; which will confine releases during dredging to the immediate dredging area.

Second, the limited upland site area available for disposal of the dredged sediments and the high cost of offsite disposal dictated stringent controls on dredging tolerances. These included a combination of penalty and incentive clauses in the construction contract and the specification of state-of-the-art dredge positioning and instrumentation system to prevent excessive overdredging.

Finally, the port’s commitment, under the current agreed order with Ecology, to complete the project as soon as possible required an expedited design schedule, which resulted in Landau Associates compressing what would normally be a six- to nine-month design process into three months.


Project permitting also presented numerous challenges. The recent listing of chinook salmon as a threatened species under the Endangered Species Act (ESA) has added a whole new dimension to the permitting of marine projects, even when the result is a net improvement to the environment.

Obtaining the Nationwide 38 permit for dredging from the U.S. Army Corps of Engineers required formal consultation under Section 7 of the ESA with the National Marine Fisheries Service (NMFS), as well as informal consultation with the U.S. Fish and Wildlife Service.

The permitting process, including formal consultation, was completed in 11 months, a significant accomplishment, given the backlog and permitting requirements resulting from the recent ESA listing of chinook. Much of the credit for obtaining this permit in a timely manner can be attributed to Port Commissioner Jeff Dickison, who was instrumental in getting the NMFS to commit its resources to the project. Given the monumental workload within both the corps and the NMFS, this project can be considered a notable success by both of these agencies and the port.

Landau Associates has worked with the port throughout this project to arrive at a remedy that addresses the many environmental concerns and interests, while also balancing budgetary constraints. This has been an integral element of our approach, from the early cleanup goal strategy development through remedial construction.

The CPC cleanup has been an expense that the port never anticipated when it leased the property so many years ago, leaving a legacy of contaminants that impacted the marine habitat along the waters of Budd Inlet. While remediating the site to a productive state for future beneficial use has been a costly endeavor for the port, the resulting environmental and habitat improvements are benefits to be enjoyed for years to come.

Larry Beard is a professional engineer and managing principal at Landau Associates. Diana Badowski is the firm’s marketing manager.

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