Denver’s Confluence Park
is still an ongoing construction project on Dec. 24, 2015. Work has been delayed after coal tar was discovered. " border="0"/>
Denver's Confluence Park is still an ongoing construction project on Dec. 24, 2015. Work has been delayed after coal tar was discovered. (Cyrus McCrimmon, The Denver Post)

A project that's causing an eyesore at Denver's Confluence Park probably will sit dormant for much of this year because excavators discovered coal tar buried at the river's edge.

The dug-up Shoemaker Plaza site, on the west bank of the South Platte River, has been quiet for at least six months. A metal dam set up in the river to restrict its flow into the project area is still up, and that stretch of the river path has been closed to foot and bike traffic, also cutting off access from 15th Street to the REI flagship store.

Denver’s Confluence Park.
Denver's Confluence Park. (Cyrus McCrimmon, The Denver Post)

Denver Parks and Recreation is overseeing the $4.2 million project to replace the plaza and trail ramps and to improve accessibility. A parks official says construction probably won't resume until late summer at the earliest.

It's all because of the discovery right at the riverbank of the coal tar — a byproduct of gasification from a century ago that is buried in patches along the river in that area and must be removed carefully.

"There could not have been a worse place to find this stuff," said Michael Bouchard, Parks and Rec's assistant director of capital projects.


Site work by ECI Site Construction Management began in March, with a goal of finishing the project by this August. The project was slowed by repeated rainstorms in May that swelled the river around the dam.

Then workers discovered the sludge during excavation.

The continuing delays are disheartening to Lorraine Parker, an attorney who works in the Riverpoint office building that is adjacent to the site.

"The aesthetics is one part," Parker said. "It's very disheartening to look out on such a mess every single day. But it's also the inconvenience.

"It's just like a black eye in a very central part of the city, and there's been just no communication. There is nothing posted at the site telling anyone what's going on."

Parks and Rec will reopen access to the trail in the next couple of weeks, Bouchard said.

But the coal tar's proximity to the river's edge complicates removal, he said, requiring plans that still are being finalized with local and state health and environmental officials.

He said Parks and Rec could announce its new plans for the project in the next two weeks.

The coal tar isn't hazardous, Bouchard said, but it's a contaminant that workers must take care to keep from seeping into the river during removal from the tight site.

At the same time, they will probably have to treat any water that's pumped from behind the dam back into the river.

Bouchard said the delay until late summer will avoid the uncertainty of high river flows during spring's rainy season. "High water would not be our friend when we get back into the river," he said.

The city is committed to finishing the project, Bouchard said, but the contaminant's discovery also likely will bust the original budget.

"We are looking at maybe redesigning some components of it (to save on costs)," he said.

Jon Murray: 303-954-1405, This email address is being protected from spambots. You need JavaScript enabled to view it. or @JonMurray

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