By: Ann Boeholt and Camille Felkins, Atlas Senior Environmental Managers

Adaptive management is often described as a best practice, but its value is most evident when projects face conditions no plan can fully anticipate. This case study — shared at the — illustrates how flexibility, collaboration and observation helped guide a project in a complex wetland system on Tribal lands.

Salmon, Sovereignty and Fish Passage

Pacific salmon have long been central to the cultures, economies and lifeways of Pacific Northwest Tribes. Over time, however, state highway infrastructure contributed to fragmented aquatic systems, limiting access to historic spawning and rearing habitats.

Since the 1990s, the Washington State Department of Transportation (WSDOT) has worked with Tribes and the Washington Department of Fish and Wildlife to identify and address fish passage barriers across the state highway system. This work accelerated significantly following a 2013 permanent injunction that established a 2030 deadline for replacing approximately 400 barriers — those expected to reconnect roughly 90 percent of the targeted habitat. Today, this ongoing, collaborative effort focuses on restoring connectivity within waterways that often intersect sensitive environmental and regulatory settings.

A Culvert, a Wetland and Changing Conditions

One such project along U.S. Highway 101 involved installing a fish‑passable culvert in 2025 to restore natural stream function. Adjacent to the site was a mosaic wetland system within the Quinault Indian Reservation.

Shortly after construction, a high‑flow event caused nearby Harlow Creek to overtop its banks. Water moved across the newly graded wetland, forming overflow channels and flow paths not anticipated in the original restoration design. While the culvert performed as intended, the surrounding wetland — newly planted and not fully stabilized — responded rapidly to these conditions.

These changes introduced challenges. Permit requirements included specific restoration and stabilization goals designed to meet water quality standards, while the wetland’s natural response made a rigid, prescriptive approach difficult to apply. In addition, the stream’s new flow path through the wetland meant that no in-stream work could occur until the following summer construction window. Any potential retrofit work within the wetland or stream would also require careful coordination, as these conditions coincided with the federal government shutdown in fall 2025.

Managing Complexity Through Collaboration

Responding effectively required close coordination among WSDOT, Tribal partners and multiple regulatory agencies. Additional constraints, including narrow in‑stream work windows and limited agency availability, reinforced the need for an approach that was both practical and adaptive.

Rather than attempting to force the system back to its original design assumptions, the project team proposed a flexible, adaptive path forward.

Letting the System Inform Solutions

In the near term, the team implemented minimal erosion‑control best management practices to protect the site while limiting additional disturbance. At the same time, they committed to ongoing monitoring to better understand how the wetland functions under post‑construction conditions.

Monitoring showed that the new overflow channels aligned with the wetland’s mosaic character. While the final design solution is still evolving, the longer‑term approach shifted toward stabilizing those channels within the floodplain — supporting ecological function and permit objectives while working with natural processes.

Together, these decisions reflect how adaptive management can support effective outcomes in dynamic environments by allowing real‑world conditions to inform design, permitting and long‑term performance.

Join Us at NAWM

We will share additional lessons learned from this case study during our presentation, “Implementing effective adaptive management to meet project goals in the face of unforeseen and changing conditions,” at the on Thursday, April 30, at 11 a.m.

If you are attending NAWM, we invite you to join the session and connect with us or continue the conversation on LinkedIn.