Washington is building interstate overpasses to help wildlife avoid collisions with cars, and allowing the animals natural migratory patterns to take place with less accidents. Recently, Washington State Department of Transportation crews commenced construction on the state’s first animal overpass, costing $6 million. The overpass is essentially a bridge that spans 150 feet in length, and is covered with vegetation to let elk, otters, bears, and even mice cross over the bustling I-90 expressway.
A rendition of the Price Creek crossing site. Credit: SeattleTimes
“I-90 has a tremendous impact on wildlife in the Cascades,” said Jen Watkins, of Conservation Northwest and the I-90 Wildlife Bridges Coalition. “Animals fundamentally require the ability to move on the landscape, and if we prevent them from doing that we can block their ability to find food and mates and new habitat when conditions change.”
The project entails converting a 15-mile stretch of I-90 into a wildlife-friendly roadway. Upon finishing, the portion of I-90 from Hyak to Easton will include more than 20 major overpasses and underpasses constructed partially or entirely with wildlife as the focus. Also, many small culverts will be rebuilt to make passage easier.
These wildlife overpasses are riding the coat-tails of a billion dollar project designed to widen I-90 from 4 lanes to six, straighten curves, reduce avalanche dangers, and improve the general driving conditions on one of the country’s most-traveled mountain highways. Though the well-being of animals wasn’t a top priority for the WSDOT, in order to have the expansion project accepted, the Forest Service and conservation community had to be on board.
The I-90 cuts right through the heart of a massive forest on both sides of the Cascade crest, from the Canadian border, to Oregon. That kind of a division line can cause serious problems, especially for predatory animals that require vast territories like bears and cougars. It can also inhibit re-population of rare species like pine martens and wolverines which already have a short supply of mates. Inclusive of all species, the isolation can reduce genetic diversity which is meant to help animals survive outbreaks of disease.
Facts like these are what turned the WSDOT into an enthusiastic supporter of wildlife projects, and the implementation of wildlife overpasses and underpasses immediately followed.
Written by Raven Fon
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