Acoustical Imaging Cameras for the Inspection and Condition Assessment of Hydraulic Structures

This Coastal and Hydraulics Engineering Technical Note CHETN describes the initial results of an investigation to determine the feasibility of using acoustical imaging for underwater inspection of structures. Visibility in clear water for the human eye and optical systems such as video cameras extends to about 15 m with appropriate lighting. However, the lack of visibility caused by the presence of suspended material in some rivers and impoundments presents many mission problems for personnel of the U.S. Army Corps of Engineers. Typical situations in which lack of visibility causes problems include assessing conditions of underwater structures such as gates and concrete piers, which are Operation and Maintenance issues positioning of float-in structures, a construction issue the investigation of archeological sites and detection of endangered species. Currently, condition assessments typically involve the use of divers to inspect and record the condition of underwater structural components. This is expensive and often poses the risk of personal injury to the divers. Ultrasonic imaging system technology originally developed for the medical field helps provide potential solutions to the problems of poor visibility in turbid water. The U.S. Army Engineer Research and Development Center ERDC in Vicksburg purchased an acoustical camera to evaluate and further develop its capability as a tool to aid in the inspection of structures in turbid water.