By Jen Mannas, Wildlife Naturalist
A large construction project is underway on I-90 just east of Snoqualmie Pass. The result of this project will be a six-lane highway that will increase the flow of traffic, making the road safer for people traveling in this corridor.
But what about the animals that live in the area?
When planning for this project, several organizations including Conservation Northwest and the Washington Department of Transportation (WSDOT) looked at the impacts this barrier has on the surrounding habitat and wildlife.
I-90 bisects the Cascades, inhibiting movement of wildlife in the area. Widening the highway would make it even harder for wild animals to find new mates and new habitat when environmental conditions change. With this in mind, one of WSDOT’s goals for the I-90 expansion project was to improve connectivity for wildlife.
WSDOT has included more than 20 crossing structures in their plan, including wildlife underpasses and the first wildlife bridges in Washington. These structures have been proven to work in other areas across the country and in Canada.
The first phase of this project consists of underpasses that will allow wildlife safe passage under the highway. They feature long stretches of raised highway and wildlife-sized culverts that are wide enough for larger mammals to pass through, as well as structures smaller animals can use for safe passage. They also allow streams and creeks to keep flowing, which helps amphibian and fish populations.
Wildlife undercrossing at Gold Creek courtesy of Conservation Northwest. Artist's rendering of wildlife overpass courtesy of Washington State DOT.
Phase 2, which began on June 9th, includes constructing the first ever wildlife bridges in Washington. These 150-foot-wide overpasses will allow safe passage for wildlife over I-90 and will be fully vegetated with native plants and shrubs to give animals the illusion that they never left the protection of the forest. WSDOT plans to build two of these bridges along the I-90 corridor and they are expected to be completed in the fall of 2019.
Agencies will be monitoring the effectiveness of these structures using remote cameras to determine how often and when they are being used. Some of the wildlife underpasses are already completed and being monitored. Check out some of the images on Conservation Northwest’s website.
This groundbreaking wildlife connectivity project will not only help improve the overall health of the wildlife in the Cascades but also help keep them off the interstate, improving the safety of wildlife and humans alike. We at PAWS Wildlife Center see firsthand the effects of road collations on animals: In the past five years we have received more than 500 patients who were hit by a vehicle, many of whom were too injured to be released back to the wild.
This project is a great start to making our roadways safer and keeping our wild habitats connected to ensure a healthy future for wildlife.
For more information about this project, check out these useful sites:
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