There’s heavy equipment operating at Tacoma’s Dune Peninsula Park. Here’s what’s up
On a given day, visitors at Tacoma’s Dune Peninsula Park take in views of Vashon Island, Puget Sound and the towering crown of Mount Rainier. In the coming weeks and months, they’ll also see a barge, excavators and a crane just offshore.
From late August through early 2024, the Environmental Protection Agency and Army Corps of Engineers will be working from the barge on the latest step in continued shoreline maintenance at the park: replacing a cap intended to contain historic contamination from the Asarco copper smelter.
Before it was designated as a Superfund site in 1983, the Asarco smelter operated for nearly a century, leaving surrounding soil, water and sediment riddled with copper contamination. The breakwater peninsula where the park now stands is entirely comprised of slag, a byproduct of the smelting process.
Metro Parks Tacoma, the EPA, the Washington Department of Ecology and other partners have invested millions of dollars into cleaning up the site – and while Dune Peninsula remains safe for visitors, replacing the shoreline cap will help make it even safer, said EPA Project Manager Kristine Koch. Upcoming work will address pockets of damage on a shoreline cap installed by Asarco in 2000, which has seen a gradual breakdown following the 2001 Nisqually earthquake.
“It’s not like all of [the cap] is gone, but there’s a lot gone – enough that we needed to do something about it,” Koch told The News Tribune.
Koch said the original cap, a layer of geotextile fabric with rocks stacked along the shoreline, has a steep grade. Over time, waves crashing into that steep grade have caused it to begin falling apart.
“Wave action breaks down the slag, and every time it breaks, it leaches heavy metals in the water,” she said, adding that those heavy metals, especially copper, create hazards for surrounding fish and wildlife.
By comparison, Koch said, the new cap will be built to withstand at least a magnitude seven earthquake. The design will have a shallower grade, allowing waves to more easily dissipate, and it will also use larger rocks to armor the shoreline.
“It keeps all the contaminated stuff, which is most of the peninsula, in place,” said Roger Stanton, Metro Parks capital program manager.
The project, a $20 million undertaking, is funded by the EPA using funds awarded from the Asarco bankruptcy settlement. Crews will begin by repairing a stormwater outfall on the southernmost end of the park and will transition to shoreline work on Aug. 28. Using bulldozers and excavators, they’ll remove the old cap and install a new one, working from south to north.
Koch said working in the water from a barge is an easy way to minimize impacts to park visitors on land; although the immediate work zone will be fenced off, people will be able to access nearby paths. Crews will also be timing work with low tides to help minimize environmental impacts and will engage in ongoing water quality monitoring.
While the upcoming work gives an unmistakable nod to Dune Peninsula’s industrial legacy, it’s also a reminder of the millions of dollars worth of cleanup, landscaping and development the site has seen.
Prior to becoming a park in 2019, the land where Dune Peninsula Park stands was a heap of brown slag. Now, its grass-lined paths bustle with skateboarders, cyclists and runners nearly every day of the year, and its waters draw local kayakers.
“We took it from what looked like a moonscape – just rock – and turned it into a world-class park for Tacoma,” Stanton said. “It’s a cool story of taking … something from our past that maybe wasn’t thought through very well and revitalizing it into something that we will get to utilize for generations.”
For Stanton, replacing the cap fits into a history of maintenance and improvement he hopes Metro Parks and its partners will continue for years to come.
“Today we are more than ecstatic that this incredible piece of property that we manage is having a keyed-in, appropriately installed, adequately designed armoring that goes around the outer edge of the peninsula,” he said.
This story was originally published August 18, 2023 at 5:00 AM.
