ASSESSMENT, RESTORATION, AND ADAPTIVE MANAGEMENT OF THE N PUYALLUP TRAIL, MOUNT RAINIER NATIONAL PARK

The N Puyallup Trail was once the last 3-mile leg of the Westside Road construction project of 1934. The stretch proved difficult to maintain, leading to its closure to the public in 1985. It was converted to wilderness area in 1988. The trail has since experienced significant damage, putting cultural resources at risk. The nearby N Puyallup River has also been designated as endangered bull trout habitat.

In summer 2016 I performed an investigation to assess hazards to the trail and river. I found that most damages to the trail are caused by unmanaged surface water. Water piracy on the forest road surface has resulted in severe incision of the trail, and caused shallow landslides in the fill slope. Many of these landslides become debris flows capable reaching the N Puyallup River and damaging the aquatic habitat. Analysis of rainfall data shows increases in rain intensity and lengthening of the wet season.

Increases in rainfall intensity from climate change will accelerate surface water damage. The undersized drainage network has become less functional each year, with results showing that total loss of trail sections could occur in <5 years. Damage to the trail harms the river via fine sediment lowering the water quality and landslides altering the habitat. The designs implemented are intended to reinforce the trail drainage and stabilize the surface. The goal is to reduce the erosion and mass wasting leading to the N Puyallup River. Repairs were installed and maintained using no mechanized assistance, with materials sourced on site.

This project has been an opportunity for the park to demonstrate that it prioritizes the conservation of its lands. By using these plans the park has kept to its commitment to preserve cultural resources vital to the historic character of Mount Rainier. The park also honorably accepted responsibility for its past construction efforts and worked to remove the effects on the landscape, proving its commitment to environmental stewardship.

Use of these designs exemplifies how trails can be updated in response to changes in climate. We raise the awareness of what can be done to prepare trails and improve repair practices for the future, and further the collaboration between park maintenance and researchers while showing that parks will be preserved for the sake of the wilderness and the citizens who cherish it.