HYDROGRAPHIC SURVEYING PROCEDURES The process of surveying a reservoir uses a combination of Geographic Positioning System (GPS) and acoustic depth sounding technologies that are incorporated into a hydrographic survey vessel. As the survey vessel travels across the lake's surface, the echosounder gathers multiple depth readings every second. Hydrographic Surveying J ohnson Engineering offers hydrographic surveying, which provides maps showing 3-D modeling or contours required for project approval. The results of the survey can also show marine geological features that pose a hazard to navigation such as rocks, shoals, reefs. The data produced may be required prior to any engineering Hydrographic survey is the science of measurement and description of features which affect maritime navigation, marine construction, dredging, offshore oil exploration/offshore oil drilling and related activities. Strong emphasis is placed on soundings, shorelines, tides, currents, seabed and submerged obstructions that relate to the previously mentioned activities. HYDROGRAPHIC MANUAL OF THE UNITED STATES GEOLOGICAL SURVEY. Prepared by E. C. MuRPHY, J. C. HoYT, and G. B. HoLLISTER. INTRODUCTION. The problem presented to the United States Geological Survey ~hen it started to make systematic stream measurements throughout the United States, was to obtain with a small sum of money a large To produce the site survey figure, bathymetric data digitised from Admiralty Chart 2326 have been re-contoured using the gridding routine within Surfer. Selected spot depths from the site survey are also shown ( for clarity, not all depths are labeled). Hydrographic data were collected using a Nortek Acoustic Doppler Profiler ( NDP, serial to the specifications in this manual, will be provided in Hydrographic Survey Project Instructions for NOAA field units and contractors or in the Statement of Work (contractors only). Field units should contact the Contracting Officer's Representative (COR),