Digitally assisted underwater inspections for hydropower

Submerged equipment and structures at hydropower projects are generally inspected at carefully determined intervals after draining or, in cases when the reservoir cannot be drawn down, by divers. Because of the considerable depths of some structures and for safety reasons, diving is not always possible or advisable. Both operations (diving and draining of submerged plant components) can be very time-consuming and expensive. In addition, diving operations pose risks to the divers themselves. Increasingly, underwater remotely operated vehicles (ROV), equipped with special inspection equipment could make significant contributions for more efficient, safer and qualitatively improved inspections. This article reports on recent experiences using different inspection technologies at pumped-storage and run-of-river schemes. In addition, current R&D activities in this field are presented.