GRANITE FALLS — What’s good for fish has turned into a temporary hassle for hikers, campers and people living along a stretch of rural highway.

The Mountain Loop Highway is torn up about eight miles east of town while workers replace a fish culvert that runs under the road.

The work is near milepost 8, where Cranberry Creek passes under the highway. The culvert there was 6 feet wide and made of aging metal pipe.

The state Department of Fish and Wildlife has identified it as a barrier to trout and salmon migration.

The narrow culvert is being replaced with a 20-foot-wide concrete passage. Crews also are creating more sheltered areas for the fish that migrate along the creek. They’ll install new guardrails on the road, as well.

Construction is expected to continue through October.

There’s a one-way detour around the work site.

Snohomish County Public Works has warned of delays lasting up to 20 minutes for alternating traffic in either direction. The bypass road runs alongside the highway so crews can divert traffic while they install the culvert, Snohomish County Road Maintenance Engineer Curtis Jasper said.

The budget for the project is $750,000. About three-quarters of that comes from the U.S. Department of Agriculture, the U.S. Environmental Protection Agency and the U.S. Forest Service. Snohomish County is paying the other 25 percent.

Bob Helmick lives about a mile from Cranberry Creek, which branches off the South Fork Stillaguamish River and flows under the highway and into wetlands on the north side of the road.

He’s not sure how motorhomes or campers are able to get around the detour. He has a hard time making it over in his SUV, he said.

There’s been heavy equipment at work and signals or flaggers in place during the busiest season for traffic on the Mountain Loop, with hikers, campers and climbers heading to popular trails and recreation areas.

On top of that, people who live up the Loop need to get through their daily commutes, he said.

“In the morning, when people are going to work, it gets so backed up that you can’t even get out of your driveway,” Helmick said.

Kari Bray: 425-339-3439; kbray@heraldnet.com