An open laboratory blade strike rig to evaluate the risk of injury and mortality to fish and to test passive sensors

Hydropower is a key source of electricity that can negatively impact aquatic ecosystems. Fish passing downstream through hydropower facilities may face increased risks of injury and mortality from mechanical collisions with hydraulic structures and machinery. Laboratory tests provide a controlled environment to evaluate turbine blade strike risks, studying injury and mortality in live fish. Previous laboratory blade strike rigs vary substantially in design and implementation, lacking a standardized approach with controlled blade velocities for cross-comparable results. To address this, we propose an open laboratory blade strike test rig with electronically controlled blade velocities (1–10 m s^-1). In addition, rigid sensor tests were performed to investigate the recommendation that 95 g is suitable to assess the severity of the blade strike, which was exceeded at strike speeds as low as 1 m s^-1. This work is significant because it provides the hydropower, engineering and biological communities with the first open and standardized method to evaluate blade strikes on fish and sensor probes. The proposed test rig enables gathering biological threshold data to estimate injury and mortality to live fish, assessing turbine blade design for improved fish safety, and increasing sensor probe accuracy without relying on live fish field studies.