*Year Session: 2022 - 04 Stream Restoration from the (WSDOT) Transportation Perspective

Eight years ago at this conference, the importance of road crossing design’s intersection with streams was highlighted in a session. Today we are re-visiting this topic and reporting on one agency’s journey in stream restoration work. Through the years, the Washington State Department of Transportation has been conducting varying amounts of stream restoration, in special project areas with complex problems. In more recent years, it is the fish passage barrier correction program that has propelled the agency’s stream restoration work, has spawned important innovations.
The sheer number of stream crossings (almost 4,000), and roadway miles in the channel migration zone, dictate a significant amount of resources must be committed to not just to protecting infrastructure, but simultaneously protecting and improving aquatic habitat. However, like a big ship, a large institution can take a long time to turn another direction. Incorporation of large wood, for instance, used to be viewed very skeptically. Resisting factors include corporate culture, institutional ‘inertia’, and for some engineers, difficulty accepting variability in design outcomes. Adding considerable urgency, WSDOT was ordered by the Supreme Court to correct about 825 fish passage barriers by the year 2030. To date, about 80 have been corrected.

Providing long lasting high quality habitat at stream crossings has numerous challenges. The reach must be passable in the first rainy season following construction, and must remain so into the future. Relatively small changes in the constructed channel can greatly affect passage. Crossing length can also be a challenge, as many fish passage barriers are culverts that are longer than 400 feet. However this has spawned innovations in habitat complexity features. Additionally, systemic degradation or aggradation of some stream reaches presents significant design challenges for ensuring quality habitat in the future. Designing crossings to account for the effects of climate change is also a considerable challenge.

Today, the Washington State Department of Transportation has a fish passage program unique in the country, and is continually improving. Because of the significance of the court mandate, the agency has worked with co-managers, and developed procedures and protocols organically, in some cases addressing gray areas in existing regulations and guidelines. However, in many cases, the restored stream crossing has higher quality habitat than adjacent stream reaches. This session will describe the agency’s programs, lessons learned, and challenges and innovations with various restoration aspects. We hope to share our experiences with similar agencies whose mission might be peripheral to stream restoration but that face similar mandates.