Largest wildlife crossing in country coming soon to Snoqualmie Pass

[Article by Guest Writer, local business owner and North Bend resident, Melissa Grant]

What is an animal crossing and why is WSDOT spending a lot of money to install them across I-90 through Snoqualmie Pass?

Animal crossings, also known as ecoducts or wildlife bridges, are quite common in Europe. Countries like the Netherlands, Switzerland, France, Canada and Germany have been using various structures to reduce human-wildlife conflict since the 1950’s. Washington State is now joining those countries with efforts to allow animals to cross human structures safely and reduce animal-car collisions.

Habitat fragmentation is a term used to describe what happens to wildlife when highways, railroads, canals and power lines divide the areas where wildlife roam. The impact of roads on wildlife is also known to have a greater detrimental impact than clear cutting. These bridges will help endangered species thrive and connect previously disconnected populations.

Along with the conservation concerns, car collisions with animals are a significant problem causing much cost in property and injured drivers and passengers. An average sized Elk can weigh upwards of 500 pounds which can cause much damage in an automobile accident. Estimates number traffic accidents with deer alone in the millions with costs possibly in the billions and loss of human life in the hundreds.

Ten years ago the Washington State Department of Transportation (WSDOT) started planning a massive, multi-year [estimated] $1 billion expansion of I-90 between Hyak and Easton that redesigns and adds two additional lanes to the heavily traveled east-west connector route. 28,000 cars drive over Snoqualmie Pass on an average weekday and MANY more on a sunny weekend. Admittedly WSDOT wasn’t terribly concerned with the animal population when they started the project, but the US Forest Service owns the right of way and the land is long term project for them. After some disagreement between engineers and biologists, the I-90 project was born with WSDOT a now enthusiastic partner.

When finished, the expansion will include 20 major underpasses and overpasses built with wildlife in mind. Some small culverts will also be rebuilt to assist animal passage. These bridges are built to seamlessly blend in with the forest and to accommodate animals that like to be out in the open, such as elk. Animals who like to on the edge of the forest such as fox and animals who like to be in a forest canopy. If the crossings look like the forest, animals will be less likely to thoughtlessly venture out on to the highway.

The first arch for the wildlife crossing was installed east of Snoqualmie Pass near Lake Keechelus on September 21st and when finished it will be the largest overcrossing in North America.

To learn more visit Conservation Northwest’s I-90 Wildlife’s Corridors Campaign webpage HERE.

A design visualization of the completed Keechelus Lake Wildlife Overcrossing. Source: WSDOT
A design visualization of the completed Keechelus Lake Wildlife Overcrossing. Source: WSDOT


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  • Isn’t it encouraging when the Department of Transportation can respond positively to those that have a larger vision of the impact this roadway widening will have. This is an exciting story to hear and observe. Thank you for posting.

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