Digital twins and blockchain help protect Europe’s waterways from pollution

Europe’s inland waterways are entering a new era of smart water management as researchers and public authorities deploy digital technologies to monitor water quality and prevent pollution. The EU-funded ReNEW project is spearheading this transformation, combining real-time sensors, digital twins and blockchain to protect rivers like Portugal’s Douro while supporting cleaner inland navigation.

Stretching over 41,000 kilometres, Europe’s river network is vital for freight, tourism and local economies. But with growing activity comes increasing environmental stress—especially from wastewater pollution. On the Douro River, a popular route for tourist cruises, authorities face challenges in enforcing water protection rules.

To tackle illegal discharges, an innovative monitoring system includes smart sensors in wastewater tanks on select tourist vessels that track water levels, time, and GPS location

“Passenger ships are becoming more popular as tourists discover the area,” said Filipe Martins from APDL, the port authority overseeing the Douro. “That’s good. But it’s also putting more environmental pressure on the river.”

To tackle illegal discharges, APDL and ReNEW have implemented an innovative monitoring system. Wastewater tanks on select tourist vessels are fitted with smart sensors that track water levels, time, and GPS location. This data is recorded in a blockchain ledger—ensuring it is permanent, tamper-proof, and fully traceable.

“In this way, it’s immutable, it cannot be changed,” said Martins. “These records are also kept forever. Nobody can tamper with the data.”

If a discharge occurs outside authorised collection points, the system automatically issues a fine. This streamlines enforcement and helps level the playing field between compliant and non-compliant operators.

“Honest companies pay for handling their wastewater while polluters don’t, if they aren’t caught,” Martins added. “Environmentally compliant shipping companies are having trouble competing with operators who don’t always follow the same standards.”

Beyond enforcement, the project is building advanced digital models — digital twins — of river systems. These virtual replicas are created by combining data from riverbed sensors, weather forecasts, and hydrological models. On the Douro, the digital twin helps predict floods and droughts, improving planning for tourism, navigation and agriculture.

Similar innovations are being tested in ReNEW’s other “living labs” in Belgium, France, Germany and the Netherlands, where researchers are monitoring air and water quality, and developing smart infrastructure to support cleaner transport on inland waterways.

“The solutions we are developing represent some of the most strategic contributions of the ReNEW project,” said project coordinator Janeta Toma. “They reflect our ambition to deliver practical, scalable innovations that strengthen the IWT sector.”

With pollution-monitoring sensors, blockchain-based accountability and predictive digital twins, ReNEW is helping ensure Europe’s rivers remain clean, resilient and sustainable for generations to come.