Hydrographic Surveys

Hydrographic surveys support the planning, engineering design, construction, operation, maintenance, and regulation of navigation, flood control, river engineering, charting and coastal engineering projects. 

Contact Us

Chief, Navigation Section
(206) 764-6908   
Chief, Waterway Maintenance Unit
(206) 764-3429   
Seattle District
Navigation Section
4735 East Marginal Way S.
Seattle, WA 98134-2385


Hydrographic Survey Unit

Our Hydrographic Survey Unit has the capability to perform sidescan, multibeam, and single beam surveys using vessels from our Floating Plant Unit. The main duties of the Hydrographic Survey Unit include:
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 Coastal engineering surveys

These 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.

 Dredging measurement and payment surveys 

These are 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

These 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.

 Reservoir sedimentation surveys

These assess sedimentation and update area-capacity curves.

 Underwater obstruction or condition surveys

These detect the existence and extent of obstructions to the safe use of waterways.

(USACE EM 1110-2-1003, 2002)

Hydrographic Survey Data

Available Seattle District hydrographic survey data is available on the U.S. Army Corps of Engineers Survey & Mapping website.

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