On March 8, Northwest Trail Alliance hosted an Advanced Trail School: Trail Building Start to Finish at Hagg Lake, bringing together dedicated volunteers for a hands-on, real-world application of sustainable trail building practices.
This was definitely a working classroom.
The focus of the day was constructing a reroute to address a significant erosion issue where the existing trail corridor was actively failing. The hillside had begun sloughing downhill toward the lake, creating an unsustainable and unsafe trail alignment. This provided the perfect opportunity for participants to engage in the full lifecycle of trail building- from assessment to construction- using the same principles outlined in our Trail School curriculum.
From Flag Line to First Cut
Participants began by walking the proposed flag line, evaluating its viability through the lens of sustainability. This included assessing drainage patterns, slope, and overall alignment to ensure the new trail would withstand the environmental pressures that caused the original failure.
With alignment confirmed, the group moved into corridor clearing- removing debris and vegetation while being mindful of the surrounding ecosystem. Sword ferns were carefully set aside, not discarded, with the intention of reusing them later in the project.
Building with Purpose
A significant portion of the day was dedicated to cutting in a full bench along the hillside- arguably the most critical and physically demanding aspect of trail construction. Participants worked together to establish a durable tread built into mineral soil, reinforcing the importance of proper benching for long-term sustainability.
Throughout the build, instructors emphasized key principles such as contour alignment, outslope, and the role of drainage in preventing future erosion.
Setting the Stage for Re-Naturalization
While time did not allow for re-naturalizing the old trail during the class, participants played an important role in preparing for that next step by salvaging sword ferns and fallen logs and staging materials for future use. A dedicated crew returned the following weekend to complete the re-naturalization work- this is when those extracted ferns were replanted to restore the old corridor and help guide users onto the new, sustainable alignment.
Ferns were also used as natural “anchors,” helping define the new tread and discourage trail widening over time.
Strong Partnerships Make This Work Possible
We were also joined by Ranger Sean Little from Washington County Parks, NWTA’s land manager partner at Hagg Lake. Washington County is thrilled with the strength of this partnership, which makes projects like this possible. Together, we are creating safer, more sustainable, and more enjoyable trail experiences for the community.
Building More Than Trail
This class demonstrated what makes NWTA’s Trail School unique: learning by doing, on projects that matter. Participants didn’t just learn concepts- they applied them in real time to solve a legitimate trail issue, contributing to a safer and more sustainable trail system at Hagg Lake.
Huge thanks to everyone who showed up ready to learn, work hard, and steward our trails. This reroute will serve as a lasting example of sustainable design and the power of volunteer-driven trail stewardship.