Why deer, coyotes and salamanders cross Interstate 90 isn't so much the issue. What state and federal transportation planners care about is getting the creatures safely across a busy stretch of the freeway east of Snoqualmie Pass.
Beginning today, residents can review and comment on a plan to widen 15 miles of I-90 from four lanes to six -- and add a unique series of wildlife crossings that usher animals over and under the bulked-up thoroughfare.
"It's a pivotal project," said William Meyer, a biologist with the state Fish and Wildlife Department in Ellensburg.
The wildlife bridges and underpasses, which would be a first for Washington, are being cheered for helping animals and people by avoiding collisions between the two.
It represents a rarely seen collaboration between environmentalists and government officials from a multitude of agencies. And it complements years of work and millions of dollars spent preserving land in the Cascades important to countless species.
I-90 is a designated National Scenic Byway that passes through the Wenatchee National Forest, surrounded by land protected through the efforts of conservation groups and the Forest Service.
"It's Seattle's back door," said Floyd Rogalski, a natural resources planner for the Forest Service in Cle Elum.
But for many of the wild creatures living in the region, the interstate is an impenetrable asphalt barrier.
The I-90 stretch from Hyak to Easton is a bottleneck squeezed from the west by urbanization and the east from agriculture and increasing development. The highway isolates populations of animals, reducing genetic variability and making them more vulnerable to disease and wildfires. It prevents migration, limits the search for food and keeps offspring from venturing into uninhabited territory.
The plan, which is being led by the state Department of Transportation and Federal Highway Administration, offers multiple strategies for improving I-90.
One option is to leave it as it is and simply maintain and patch up the freeway as needed.
The other is to widen it to six lanes, straighten some hazardous curves, stabilize crumbling slopes, make improvements to reduce the need for avalanche closures, repair damaged pavement and build passages for wild animals. The costs for this alternative range from $410 million to $980 million, depending in part on the type of animal crossings constructed.
This year, the Legislature committed $387.7 million toward the project. Construction is scheduled to begin in 2011 and could take up to seven years to complete.
The leading roadkill-prevention strategy calls for building 14 animal passageways. Some are expanded streamside areas that cars and trucks would pass over on long bridges. Other wildlife corridors would resemble large tunnels or culverts. There's also a plan to guide animals over the freeway using a natural-looking, vegetated land bridge.
Deer, elk, grizzly bears and moose appear to prefer the land bridges, while cougars seem to like the more secretive underpasses, according to researchers.
Fences would be built to help funnel the animals toward the bridges and discourage them from crossing the asphalt. Over time, research shows, the creatures seem to learn where the passages are and use them more often.
"It's a growing science, and it's really cool to see what they're doing on I-90," said Amanda Hardy, a research ecologist at Montana State University's Western Transportation Institute. "Washington is really in the forefront in their efforts."
For a couple of decades, highway projects scattered around North America have been helping animals avoid becoming roadkill. There are projects in Arizona and Canada, construction is beginning on a project in western Montana, and there's Florida's famous "Alligator Alley."
Environmentalists participating in the project are urging the transportation departments to select the one most beneficial to the animals, the choice identified as Option A.
"We're looking at something that's going to be there for 60 years," said Charlie Raines, director of the I-90 Wildlife Bridges Coalition, a group of more than three dozen environmental organizations and businesses in support of the plan.
P-I reporter Lisa Stiffler can be reached at 206-448-8042 or lisastiffler@seattlepi.com
