As part of the Long Lake HED Plant Upgrade Project, AUS was contracted to survey the four draft tubes and the tailrace floor. To perform the survey, AUS utilized a multi-beam sonar system for the tailrace and a Blueview 5000 3D Mechanical Scanning Sonar mounted on a tripod for the draft tubes.  Multiple images from two types of sonar were “Stitched” together to produce a single 3 D Image of the area.