Can sustainable trail construction mitigate early-stage soil degradation and potential runoff concentration? Evidence from a controlled field experiment across five recreational activities

Recreational trails provide access to natural areas and support human well-being and environmental awareness. However, inadequate trail design coupled with rapid growth in outdoor recreation and diversification of trail-based activities threaten tread integrity and exacerbate off-trail impacts. To assess how trail design and use affect tread dynamics, we combined high-resolution Structure-from-Motion (SfM) surveys with DEM-of-difference analysis to quantify microtopographic change and shifts in surface runoff on (i) informal trails representing early-stage tread formation and (ii) purpose-built trails constructed following sustainable principles. We conducted experimental use (600 passes) including hiking (HIK), hiking with poles (HIK-P), trail running (RUN), mountain biking (MTB), electric mountain biking (eMTB), and no-use control (CTRL). All activities produced significant topographic change on informal trails (ITs). On constructed trails, no activity differed from the no-use control. On ITs, we observed no plateau across the applied use levels and fitted accumulation models suggested continued change with additional passes. In contrast, changes on constructed trails were small and fitted models indicated a tendency toward stabilization for foot-based activities. On ITs, topographic change increased with cross-slope and trail grade, whereas on constructed trails, trail slope alignment exerted only a weak influence. Finally, use on ITs increased the potential for runoff concentration along the tread, whereas construction maintained distributed drainage pattern. Overall, these findings indicate that, under the environmental conditions tested in this experiment, the specific trail construction techniques employed buffered the impacts of early recreational use across multiple activities by markedly reducing microtopographic change and preventing potential runoff concentration on the tread.