River Watchers: citizens help map visible river litter, using AI

AI enhances citizen observation

Participants photograph visible litter in their surroundings - along rivers, streams, canals, or even in parks. These images are analyzed by VITO's remote sensing team using AI models capable of detecting and categorizing not only large debris like cans and bottles, but also mesoplastics (5-25 mm), such as cigarette butts and plastic fragments. This level of granularity is a first in citizen-led litter mapping.

With AI and geotagged images, we turn everyday observations into high-resolution data that supports environmental policy and awareness. Together with River Cleanup, we create impact that matters.

Arne Van Overloop
VITO Remote Sensing

Structured data meets citizen science

The initiative blends public engagement with scientific precision. A core group of volunteers collects data on fixed routes to monitor trends over time, while a broader public contributes via a gamified interface at www.riverwatchers.be. Each image adds a point to an interactive map and earns participants 'Trash Tokens' to encourage continued involvement.

A partnership for scalable impact

The project is a close collaboration between VITO and River Cleanup, who brings extensive experience in community mobilization, awareness campaigns, and circular action. River Cleanup leads citizen engagement efforts and supports participants throughout the process - from sign-up to photo upload and beyond. The partnership ensures the project is not only scientifically grounded, but also widely supported and actionable at scale. 
River Watchers was one of three selected projects in amai!, a Flemish initiative that invites to co-create AI solutions for social challenges and builds on the award-winning Waste Watchers drone project, now bringing AI-driven litter detection to street level, accessible to anyone with a phone.