It’s a Wrap on the Cap: Port of Bellingham completes major cleanup milestone to redevelop Bellingham’s Waterfront District

A video history of the past, present, and future of the transformative Bellingham waterfront redevelopment.

Along the east side of the Whatcom Waterway in Bellingham, a layer of gray gravel stretches over the landscape. This “cap” of crushed rock and surrounding paved surfaces is a culmination of years of efforts to clean up soil and groundwater on the grounds of a former pulp and paper mill. Completion of the capping clears one major hurdle for the Port and City of Bellingham to create a new, vibrant waterfront.

Video Credit: Port of Bellingham

A historically industrial site with strong post-cleanup potential

The waterfront has always been central to Bellingham’s industrial past. Where the cap sits now was originally tideflats that were filled to create new upland for industrial use: salmon canning operations in the early 1900s, giving way to a pulp mill in the 1920s. In 2005, Georgia-Pacific (GP) sold 137 acres of land, including the 64-acre mill property, to the Port of Bellingham, and GP’s last mill operations closed in 2007. Despite the contamination that resulted from the industrial activities, the Port and the City did not give up on this property and saw the cornerstone of a new Bellingham waterfront—it only needed remediation to set the stage for productive and safe reuse.

How to Clean It Up

Heavy industrial use left some contamination in soil and groundwater across the majority of the mill property, which, for purposes of the environmental cleanup, is termed the GP West site. In 2009, the Port and the Washington State Department of Ecology (Ecology) executed an Agreed Order to investigate and determine the appropriate “cleanup action” for the site. First, Aspect completed a Remedial Investigation to document the soil and groundwater across the entire site. While the investigation was underway, the Port and Ecology agreed to proactively undertake interim cleanup actions to permanently remove areas of high-risk soil contamination (Bunker C fuel oil and liquid mercury) while working to create the cleanup plan for the larger site.

In 2013, the Agreed Order was amended to divide the GP West site into a pair of Remedial Action Units (RAUs): the Chlor-Alkali RAU that encompasses mercury contamination from a former mercury-cell Chlorine Plant on the south end of the site; and the Pulp and Tissue Mill RAU that encompasses the former pulp mill and tissue mill areas to the north. Ecology agreed to do this to expedite cleanup and facilitate redevelopment, recognizing that cleanup of the Pulp and Tissue Mill RAU was less complicated and could be accomplished more quickly than could the Chlor-Alkali RAU. In 2014, a Cleanup Action Plan (CAP) specified the final cleanup action for the Pulp and Tissue Mill RAU. The final cleanup for that RAU involves additional removal of contaminated soil, and, in a few areas, monitoring the natural restoration of groundwater.

What it takes to put a Cap on 31 Acres

A major challenge for the capping project was achieving a protective barrier across 31 acres of highly variable surface conditions remaining after demolition of the former mill, while also maintaining accessibility and stormwater drainage until redevelopment reconstructs the area. The surface that required capping was a mish-mash of material types and grades: pavements of variable type and condition, intact concrete slabs of all dimensions and heights, crushed concrete and brick, and a hill of soil that historically served as a street onramp. Further complicating the effort was a widespread surficial layer of dirt and rocks presumed to have contamination from historical activities, termed “veneer.”

Aspect was involved throughout the capping project, from conceptual design to the construction plans and specs and bid process, and then overseeing work to ensure it was done to the CAP specifications. The capping itself took about 90 days, as outlined in these photographs:

Before – Pre-existing site surfaces requiring capping

Random intact slab with "veneer" around it.

Crushed concrete from mill demolition.  Also note that the Port saved some buildings and structures, like the “acid ball” and the “pulp digester” towers shown here, to contribute to the aesthetics of the planned redevelopment.

The hill of soil that historically served as a street onramp.

During – Regrading and consolidating contaminated material 

The initial steps of the capping project included grading off the tops of the soil knolls to match surrounding grades, as well as removing the “veneer.” The latter was done with excavators, street sweepers, and even a good old-fashioned broom in some areas. All of the excavated and swept-up contaminated materials were consolidated as fill to raise grade in a low area just south of the knolls.

During – Smoothing it out

Next, the site needed to be evened out. The contaminated soil fill was graded and compacted to a flat surface. Because it was to be capped with clean imported soil, a bright orange geotextile was placed across the contaminated soil subgrade to provide visual notification for potential future excavation through the cap during redevelopment. Adjacent stockpiles of crushed concrete and brick from prior building demolition were likewise leveled and compacted – creating a firm, flat subgrade across the entire fill area.

During – Capping it off

Once the fill was consolidated and evened out, the entire 31 acres needed to be capped. The cleanup plan called for a minimum of either 3 inches of competent hard surface (asphalt or concrete pavements or foundations), or 2 feet of clean import soil/rock, overlying the contaminated soil. Ultimately, contaminated soil was capped with 2 feet of import material (6 inches of crushed rock over 18 inches of sand and gravel) on top of the orange geotextile, while the cap across the rest of the area was a combination of pre-existing competent hard surfaces and new asphalt pavements. The capping also cleaned out and secured more than 170 vaults and other subsurface structures to eliminate physical hazards to foot and vehicle traffic and to control stormwater drainage.

Done – The finished product

The finished cap will keep people from coming into direct contact with potentially contaminated soil. The project also improved stormwater drainage, and provided an overall upgrade to the site’s aesthetic. Aspect will also continue to monitor the groundwater on the site as the Port and City plan their next steps.

What’s Next: Reconnecting the Community to the Waterfront

Just as the waterfront has been central to Bellingham’s past, it is now the key to its future. With the cap in place, the potential of this prime waterfront area is just now being unlocked. The old Granary building at the corner of the cleanup site is undergoing renovations to house shops and restaurants. The City is planning for construction later this year of the first arterials and utilities, as well as a park that will allow the community to directly access the waterfront. And rather than forget the past use of the area, the City has embraced it with a public competition to reimagine the site’s “acid ball” as an art installation within the new park.