A submerged dock lays off the Fort McHenry National Monument, in the Patapsco River, Baltimore MD—and a well-known marked hazard zone. The depth surrounding the object is navigable at depths greater than 30 feet. Just over the hazard, depths are only 5-8 feet, making it impossible for a traditional survey vessel to navigate. We chose this particular location to demonstrate how an ultra-high resolution multibeam sonar can be used in conjunction with a small autonomous surface vehicle (ASV) to obtain a more complete survey of a complex and challenging area.
Nestled Northeast of the city of Folsom, California, sits the 11,450-acre Folsom Lake—formed by an existing dam on the North Fork and South Fork of the American River. It is responsible for providing irrigation, drinking water, and electricity to parts of California, as well as flood prevention for the areas situated south of the lake. Despite the low risk of a damaging occurrence, it was decided (under the Reclamation Safety of Dams Act) that preventive measures needed to be taken to protect those living downstream. Construction of a new auxiliary spillway is in progress, which will provide a means for a steady water outflow during an increased water flow event. Carried out in phases, this project requires surveys from land and water to ensure successful completion. The $900-million cooperative project between the U.S. Army Corps of Engineers, U.S. Department of the Interior, and Bureau of Reclamation will assist the Sacramento region to achieve the 200-year level of flood protection.Completion of the auxiliary spillway is scheduled for late 2017.