Speaker
Prof Dr. Mário J. Franca, Institute for Water and Environment, Karlsruhe Institute for Technology (KIT), Germany

The seminar is open to the public. To join online, please contact seminars@cluttereawag.ch for access details.

Abstract
Floating debris is often found in large quantities during floods. It can include various items such as plastic, wood, and other materials that float on the water's surface, causing numerous adverse impacts on human well-being and the environment.

Plastic litter, in particular, poses a significant threat to river and marine life and ecosystems. Littering also imposes a substantial economic burden on local authorities due to the costs associated with cleaning and removal. During floods, urban debris presents another challenge as it becomes mobile, transforming into Urban Flood Drifters (UFDs). These UFDs endanger human and non-human lives, damages proprieties by impact, can clog and reduce hydraulic efficiency of urban drainage, and exacerbate flood consequences, creating further challenges for flood management. Conversely, the European Floods Directive, which guides European governmental agencies and practitioners in flood risk management, only timidly suggests the consideration of transported sediments and debris in flood risk assessments. Consequently, flood risk assessment is mainly conducted in terms of water surface levels with some consideration of flow velocity, overlooking the significant impact of transported debris.

Our research efforts focus on understanding the hydraulic transport of flotsam, including inception of motion and transport mechanics. This presentation will share insights from our research, including results on the transport of plastics in rivers, the inception of motion of large debris during floods, and the inception of motion and transport of urban litter caused by pluvial floods. Our findings ultimately aim to contribute to better management strategies for urban floodwaters and mitigation of the environmental impacts of flotsam.