Acoustic and Visual Debris Detection for Collision Avoidance in Turbine Protection Systems

Alaska’s remote communities rely heavily on costly diesel fuel,making hydrokinetic (HK) energy from free-flowing rivers apromising renewable alternative. The Tanana River Test Site nearNenana, Alaska, a well-characterized site with significant seasonalflows, is ideal for developing and testing HK technologies. Riversflowing through wooded terrain can entrain and transport woodydebris downstream, posing risks of accumulation or impact oninfrastructure. Thus, reducing diesel reliance via HK turbinesrequires addressing operational challenges, including debrisimpacts on turbine rotors and instrumentation.This study advances debris detection technology for hydrokineticturbines in turbid river environments by evaluating underwateracoustic cameras and above-surface visual observations. Thecurrent system aims to provide a preliminary foundation for a futureintegrated bi-modal monitoring approach—acoustic sensingcaptures both floating and underwater debris trajectories, whilevisual algorithms identify and classify floating debris in real time—toenable early warnings of potential collisions with turbine rotors andinstrumentation. Two separate field trials were conducted in theTanana River Test Site. First, controlled debris with GPS tracking wasdeployed while monitoring with two different acoustic cameramodels to assess detection reliability. Then, optical camerarecordings were performed on a different date to assess surfacedebris detection. While acoustic and visual technologies have beentested independently to assess their individual capabilities, futurework will focus on integrating these complementary sensingdomains to enhance detection reliability, system robustness, andautonomous turbine protection. This combined approach leveragesthe strengths of both sensing modalities to overcome challengesposed by turbidity and adverse surface visibility conditions, with theaim of delivering timely alerts to mitigate physical impacts andreduce maintenance costs.