Extreme weather events, such as torrential rainfall, are becoming increasingly frequent owing to global warming; thus, developing new technologies for levee reinforcement and maintenance is essential. Conventional reinforcement methods, often relying on artificial materials, have limitations such as hindering vegetation growth and causing environmental issues. This problem was addressed in this study by evaluating the durability of a biopolymer-based levee reinforcement technique that combines a natural biopolymer with aggregates to provide an eco-friendly solution for levee protection. A fixed steep-slope flume at the Rural Research Institute of the Korea Rural Community Corporation was used to assess the permissible flow velocity and shear stress of the biopolymer-based method. Measurements and video analysis were performed using a high-speed camera as an advanced noncontact sensing technology to accurately determine flow velocities and assess material performance under extreme conditions. The biopolymer reinforcement remained undamaged under maximum discharge conditions in the flume (flow velocity of 9.4 m/s; energy slope of 0.7908). With a shear stress resistance of 372.37 N/m2—approximately 4.1 times greater than the target requirement of 90 N/m²—the biopolymer-based material demonstrated superior durability over conventional revetment systems. This study highlights that this method has significant potential as a cost-effective, efficient, and environmentally sustainable alternative to traditional levee reinforcement methods and offers enhanced performance and durability.