Overhaul in works for I-90 through Cascades

YAKIMA – Each Labor Day weekend, about 58,000 vehicles venture across the rugged Cascade Mountain range on Interstate 90, the east-west thoroughfare that stretches from Boston to Seattle.

Near the West Coast, it’s not necessarily a trouble-free route. Snoqualmie Pass saw higher than average snowfall this year. Rockslides and avalanches have long hampered traffic in the mountainous region, where closing even a single lane can mean delays of hours.

But travelers will find a new scene this time next year, with construction beginning on a project – estimated at $1 billion once fully completed – to rebuild parts of the highway. Plans include new expanded snow sheds to alleviate avalanche danger, slope stabilization, new bridges and road resurfacing.

In a twist, the project also aims to better protect drivers from ambling wildlife by building bridges and underpasses to lure animals away from the road and improve fish passage. Similar structures have been built elsewhere in the United States and in Canada’s famed Banff National Park, but it’s one of the largest such projects ever undertaken on a major U.S. interstate.

“The start date can’t come soon enough,” said Jen Watkins, outreach director for the I-90 Wildlife Bridges Coalition, long a supporter of the idea. “This project really set a precedent for the state and the nation for dealing with animals on highways. We’re just excited to see it get off the ground.”

What started as a gravel road in the early 1900s became an interstate in the 1970s, but I-90 hasn’t really had significant improvements since then, said Jason Smith, the project’s environmental manager for the Washington state Department of Transportation.

Snow sheds built years ago address only two of the five chutes where avalanches are common.

In a region with heavy rain and snowfall, “it just doesn’t work anymore,” Smith said.

Transportation Department officials will seek bids for the project next spring. Construction on detour routes and excavation of Keechelus Lake, to mitigate for lost water storage for irrigation east of the mountains, should follow. The focus in 2010 and 2011: adding a lane in each direction, rebuilding bridges and snow sheds, and extending and adding areas for long-haul trucks to chain up.

Work over those three years will cost $545 million. Additional construction between Keechelus Dam and Easton is slated to continue through summer 2015. However, money for those projects, currently estimated at between $516 million and $752 million, has not yet been appropriated.

Improving the highway itself is a colossal undertaking, and efforts being made to improve traffic safety are phenomenal, said Patty Garvey-Darda, a wildlife biologist and acting ranger for the Cle Elum Ranger District of the Okanogan-Wenatchee National Forest. But what sets the project apart, she said, are the efforts being made to improve wildlife habitat.

Dozens of animal species – deer, bear, salamanders, eagles – call the Cascades home, and many become roadkill on a highway expected to see increasing traffic over the next 20 years. Sensitive species that aren’t necessarily known to roam the area, such as grizzly bears and gray wolves, can’t be ruled out, either.

The Forest Service has acquired 80,000 acres in the past decade to connect wildlife habitat and maintain viable populations of key species in the Cascades, which stretch across miles of forest and national park land. The interstate bisects the Cascades at a point already under tremendous pressure from development on both sides, Garvey-Darda said.

Think of Washington’s Cascades as an hourglass – wide at the top near Canada and at the bottom near Oregon’s Columbia Gorge, but narrow where I-90 cuts through the mountains.

“We’re really lucky because the North Cascades link to Canada and they have great habitat and great wildlife populations, but the South Cascades are isolated. That isolation would only increase as the traffic increases,” she said.

State officials have committed to keeping lanes open during construction, particularly during holidays, to limit the economic impacts of closing a major transportation artery.

“When you have large blocks of public land, people expect wildlife populations to be healthy, water quality to be healthy. That’s why we’ve put so much effort into this,” said Brian White, the Transportation Department’s project director. “It’s really exciting, finally seeing some of this work come to fruition.”