A new bridge under construction on Coal Creek Parkway is slated for completion in mid-October, opening up a major arterial above and clearing the way for migrating salmon below.

The bridge replaces an aging culvert under Coal Creek Parkway, between Forest Drive Southeast and Southeast 60th Street, that had become an obstacle to salmon migration. Construction began last May to replace the culvert, and the bridge offers the added benefit of a pedestrian underpass connecting the Coal Creek Trail on both sides of the road.

“It’s taken two seasons to construct. Mostly because of the complicated infrastructure in the road, and especially because of the Olympic pipelines,” said Bruce Jensen, design phase project manager. That required constructing the bridge in west and east segments and relocating pipelines and fiber optic cables. “All that infrastructure was moved to the first half of the bridge that was constructed during the winter.”

During this time, Coal Creek has been routed through a large pipe while crews construct a new stream bed running under the bridge. Once complete, Jensen said the bypass pipe will be removed.

The pedestrian underpass will connect the east and west portions of the Coal Creek Trail, no longer requiring hikers and bikers to cross over at Forest Drive and be rerouted back to the west side of the trail.

“It just wasn’t safe,” said Dan DeWald, who manages the parks department’s natural resources division. “We looked at options of a crosswalk. Nothing was really practical.”

The underpass will be elevated and railed, with Coal Creek running adjacent. DeWald said it will also serve as a connection for wildlife.

He said the trail system has been improved over the past six years, adding nine bridges and two stairways. Connecting the trail had been considered several years ago, but was put on hold when problems were found with the culvert. The parks portion of the project is being paid for with 2008 parks levy funds, and includes a new parking lot.

“Once we get the underpass complete, we will revisit the parking lot design,” DeWald said.