Preventing riverside littering through structural change: An action research field experiment using two intervention measures

Abstract Urgent action is required to develop effective interventions for the prevention of littering with the increase in the severity of marine plastic pollution. This study employs action research and conducted a field experiment along a riverside to evaluate the impact of interventions on littering. Action research, which involves collaboration with stakeholders, is essential for effective interventions due to the valuable local knowledge of stakeholders tailored to regional contexts. Prior to the experiment, the stakeholders were engaged in the selection of intervention measures. Across 5 months of dialogue and collaboration, relationships were cultivated with stakeholders. We then identified the Naebo River as the site and selected two interventions, namely, setting flowers and illumination. A block design was used to establish experimental and control conditions. The experiment followed a before–after design. The results indicated significant reductions in littering in both the flower‐present and illumination‐present blocks during the intervention period, and these effects persisted after the removal of the interventions. The study underscored the importance of action research in which hypotheses are collaboratively developed with stakeholders to suit local contexts. Enhanced cleaning and maintenance efforts during the study contributed to the reduction of littering, which highlights their potential impact on litter prevention strategies.