Hydrographic surveys support the planning, engineering design, construction, operation, maintenance, and regulation of navigation, flood control, river engineering, charting, and coastal engineering projects.
Our Hydrographic Survey Unit has the capability to perform sidescan, multibeam, and single beam surveys using vessels from our Floating Plant Unit. Its main duties include:
- Dredging measurement and payment surveys associated with contracted construction to measure the amount of excavated, deposited, and/or placed material in subsurface areas. These surveys also include investigative studies used for preparing contract bid documents and for directly monitoring and measuring subsequent contract performance, payment, and acceptance.
- Project Condition Surveys to determine the present condition of coastal and inland navigation channels, navigation locks, underwater features, river or flood control structures, or beach/bank erosion protection structures. These surveys are used to determine if project conditions have changed enough to warrant future construction or maintenance activities, if additional condition surveys are required at more frequent intervals, or if a greater survey coverage density is necessary.
- Underwater obstruction or condition surveys detect the existence and extent of obstructions to the safe use of waterways.
- Coastal engineering surveys are performed for a variety of purposes. In coastal areas, these surveys determine the condition of beach renourishment or support coastal engineering research studies. Surveys are also performed to study the effects of offshore protection structures (jetties, breakwaters, groins), harbor entrances, estuaries, and coastlines in areas of suspected accretion, erosion, or other material movement or transport. Surveys are also performed to develop, evaluate, and calibrate physical and numerical models used for planning and design of projects.
- Reservoir sedimentation surveys assess sedimentation and update area-capacity curves.
(USACE EM 1110-2-1003, 2002)