Safe Passage I-5

Working to connect wildlife habitat in the Cascade Mountains to the Olympic Peninsula


The Olympic Peninsula contains the second-largest mountain range in Washington and supports vast temperate rainforests and world-class biodiversity. As a peninsula, options for wildlife movements are limited by geography.

The two existing connectivity pathways are threatened by growing development pressures, particularly along the Interstate 5 corridor. I-5 is a multi-lane barrier disrupting free wildlife movement between the Cascades and Olympics mountain ranges.

This region is home to diverse species, including Roosevelt and Rocky Mountain elk, cougar, black-tailed deer, black bear, fisher, western gray squirrel, vulnerable salmon, and more.  

I-5 harms ecological connectivity and the window to address this critical issue is rapidly closing.

A bobcat, photographed by a trail camera in the mapped wildlife corridors near I-5 by Tenino. Photo: CNW

From the Chehalis Basin to the Columbia River, the I-5 corridor is experiencing a development boom. Warehouses, factories, and other structures are being built quickly, and there is  even talk of a SeaTac-sized airport  in the area. Land prices are soaring.  

The time to design and build safe crossings is now before this area is overdeveloped in key crossing locations.  

This massive and urgent effort has a strong coalition of stakeholders, including the Washington Department of Fish and Wildlife, Washington State Department of Transportation, U.S. Fish and Wildlife Service, Tribal scientists, community members, NGOs, Conservation Districts and many more.  

CNW and partners have funds deployed for looking at development patterns and land use change, but we need funding for further studies. Our capacity is limited and we need your help!  

Will you join us in saving the primary wildlife corridor in southwest Washington?

Wildlife crossings are massive infrastructure undertakings, requiring the support of numerous stakeholders and government funding. Supporting Phase One of this effort now paves the way for this project to be shovel-ready and eligible for state and federal funds in two years and have crossings in place by 2030.  

I-5’s Negative Impacts on Wildlife: 

  • From the Columbia River to Olympia, this stretch of I-5 carries 36,000 to 121,000 vehicles daily, creating a substantial barrier to natural wildlife movements. 
  • Recent research has shown that a lack of connectivity creates isolated gene pools of wildlife on either side of I-5. Lack of genetic diversity in wildlife populations increases the probability of disease and less healthy wildlife.  
  • Climate change is forcing wildlife to move to different areas. I-5 limits the freedom of movement required for some species to adapt to changes in climate and the environment. This hinders some species from reaching climate refugia or quality habitat on the Olympic Peninsula and in the Cascades.

Priority Project Goals: 

An existing structure under I-5 at Newaukum River. Our Cascades to Olympics program seeks to enhance structures like these to better serve as wildlife crossings. Photo: Brian Stewart
  • Ensure that key habitats and movement corridors are protected so wildlife can adapt and thrive in a changing world. 
  • Existing studies show the urgent need for wildlife crossings in SW Washington. We need additional science and data to support our current efforts.  
  • “Shovel-ready” projects are the most attractive for state and federal grant applications. Phase One studies will ensure this project is eligible and competitive to receive necessary government funding.  
  • Study and protect the two locations on I-5 in Washington, where wildlife corridors cross the interstate.  We will further narrow down the options and designs for crossings by studying soil that can support crossing structures, light and sound impacts on wildlife, fish passage assessments, and wildlife genetics.  

Dig Deeper: How This Project Connects to our Cascades to Olympics Program Strategy: 

  • By scientifically identifying pinch points and current safe passages for wildlife, we have prioritized two main areas: the southern and northern linkage. (see map below)
  • Working with local communities, tribes, agriculture, forestry, and other interests will be critical for success in this landscape. Conservation Northwest is well-poised for such an approach, given our successes working with stakeholders on conservation outcomes in other areas. 
  • An additional focus is on the Chehalis Basin. Engaging in the  Chehalis Basin Strategy  allows us to integrate infrastructure, habitat protection, and restoration focused on terrestrial wildlife moving through this corridor in the Chehalis management plan. 
  • Washington Wildlife Habitat Connectivity Working Group Cascades to Coast Analysis

Learn more about our I-5 habitat connectivity work

The Cascades to Coast regional map shows the greater 105-mile I-5 segment in dark blue, plus the northern and southern linkage zones. The southern linkage zone, in green, is the subject of Phase 1 work covered under this proposal. The northern linkage zone, in orange, will be the subject of Phase 2 activities.
Map courtesy of Washington Wildlife Habitat Connectivity Working Group
A rainforest scene in Olympic National Park. We’re working to improve connectivity and restore habitat between the Cascade Mountains and the Olympic Peninsula. Photo: Chase Gunnell

Keeping the Northwest Wild since 1989, we protect, connect, and restore wildlands and wildlife from the Washington Coast to the British Columbia Rockies. Our programs center on oversight of public lands, conservation practices on key private lands, and protection and recovery of threatened species, with components of climate impact, racial equity, and justice in as many programs as possible.