Technical Manual: Conduits through Embankment Dams (FEMA 484)

Conduits through Embankment DamsFigure 124.—Climber performing an inspection on a terminal structurewall.entrance and terminal structures and conduits. The focus of this section will pertainonly to ROV inspections of conduits.ROVs are normally linked to a surface power source, although untethered modelsare also available. However, untethered (autonomous) vehicles are typically largerand not used for inspection of conduits. ROVs that are linked to the surface havecables that carry electrical signals back and forth between the operator and thevehicle. Most ROVs are equipped with at least a video camera and lights.Additional equipment is commonly added to expand the vehicle’s capabilities. Thesemay include a still camera, a manipulator or cutting arm, water samplers, andinstruments that measure water clarity, light penetration, and temperature.An ROV consists of a video unit, a power source for propulsion, vehicle controllers(referred to as “joysticks”), and a display monitor. The ROV can provide real-timeviewing. Most ROVs are either observation or working class vehicles. Anobservation class vehicle is small and compact and is used for visual inspectionwhere nonintervention applications are required. Typically, observation class ROVsinclude a high resolution color video camera capable of zoom and manual or autofocus. Figure 125 shows an observation-class ROV entering the water. Precisioncolor scanning sonar is an added option, but can be expensive. Some observationclass ROVs may have a single function manipulator. Working class ROVs aretypically capable of search, survey, inspection, and light intervention to depths of218