McKim & Creed completed a six-day full hydrographic and geotechnical survey in a 7,200,000-SF area along the East Coast.
The goal of the survey was to collect a comprehensive dataset of the entire area and look for potentially hazardous objects above and below the seafloor. Services included multibeam sonar, side scan sonar, magnetometer, sub-bottom profile, and topographic surveys. McKim & Creed also furnished grab sampling and underwater video footage.
The multibeam system provided full coverage of the underwater topography of the survey area, while the side scan sonar offered a full coverage high-resolution image for locating targets above the seafloor. The purpose of the magnetometer survey was to measure the variation in the Earth’s magnetic field and detect ferrous anthropogenic features buried or exposed on the seabed, such as cables, pipelines and wrecks.
Moreover, the sub-bottom profiling system identified changes in the acoustic impedance of the subsurface geology. This indicated different sediment layers and located buried objects. Beach profiles and location of features above the water surface—such as utility boxes and manholes—were surveyed using topographic survey methods. Grab sampling allowed us to identify which kind of sediment material was present in the area and the underwater video footage provided a clear image of an object the client needed to have inspected.