Call (800) 515-6674 today to speak with a surveying engineer about your hydrographic surveying requirements.
Before you can start a bathymetric or hydrographic survey you need to have good survey control. Survey control is typically based on a state plane coordinate system for repeatability. A local coordinate system can be adopted to match prior work as needed. Also it is good to leave three primary control points on site after the survey has been completed for future use by others. The critical element for the surveyor is a limit line provided by the client showing where the survey starts and stops.
Mobilization to the site is a very important factor in hydrographic survey. Due to waters depth, the right equipment needs to be specified and utilized. The size of the boat is also a factor in determining equipment. For shallow surveys and environmentally sensitive areas we use a 12 foot boat and a Hydrolite echo sounder with the standard GNSS RTK complement. For Deep water surveys we use a bigger boat and ODM CVM echo sounder. Meridian Surveying Engineering, INC uses multi-beam echo sounders, magnetometer and sidescan depending on project requirements. After the equipment is designated for the task at hand we proceed with the hydrographic survey.
For shallow water surveys we use a hydrolite echo sounder, Trimble GNSS RTK, leadline and TSC3 data collector. The preset GNNS control is checked before starting the hydrographic survey. A sound velocity reading is used to check the sound velocity of the water. The transducer is mounted over the side of the boat and a lead line check is performed. Once all the equipment is setup and connected we start the hydrographic survey. The Hydrolite is connected to the TSC3 data collector. And the pre-programmed hydrographic lines are run.
For deep water surveys the methodology is a little more complex. The equipment list is more extensive, Hypack, Trimble GNSS RTK, leadline, TSC3 data collector, sound velocity profiler and Odom CVM echosounder. Step one: use the sound profiler to assess the sound velocity in the water at that location. Next a bar check is performed to verify/calibrate the vertical accuracy of position of the Odom CVM echosounder. After this Hypack software on a laptop is connected to Trimble GNSS RTK and the Odom CVM echosounder. Next the preplanned survey lines are run on the surface to grid the area in sufficient detail to meet the specifications. The last step is doing periodic physical lead line checks to confirm that the Hypack vertical depth values on the bottom are accurate.
Shoreline terrain can be linked seamlessly to the hydrographic data with our Faro/Trimble HD 3d Scanners.
Office post processing: the data is post processed in native format and converted to Autodesk desk format for mapping. Once the project is mapped hand checks/lead lines are used for final QA/QC to verify the sonar data calibration.
International Hydrographic Organization defines hydrography as “the branch of applied science which deals with the measurement and description of the physical features of the navigable portion of the earth’s surface [seas] and adjoining coastal areas, with special reference to their use for the purpose of navigation.”
Hydrographic surveying “looks” into the ocean to see what the sea floor looks like.
The Office of Coast Survey conducts hydrographic surveys to measure the depth and bottom configuration of water bodies. We use the data to update nautical charts and develop hydrographic models; increasingly, the hydrographic data is used for multiple purposes, through theIntegrated Ocean and Coast Mapping program.
Surveyors pay particular attention to acquiring the precise location of least (shoals) depths, to warn mariners ofdangers to navigation, and they record the precise location of aids to navigation. They also record tide or water level measurements to provide avertical reference (mean lower low water) for water depths. Surveys can also determine sea floor material (i.e. sand, mud, rock), which is important for anchoring, dredging, structure construction, pipeline and cable routing, and fisheries habitat.
Survey vessels primarily useside scan andmultibeam sonar. Sonar (which was originally an acronym for SOund NAvigation and Ranging) uses sound waves to find and identify objects in the water and to determine water depth. Some vessels may use single beam echo sounders. NOAA’sRemote Sensing Division and commercial hydrographic contractors use aircraft equipped with lidar (LIght Detection And Ranging) to measure shallow water depths in areas with complex and rugged shorelines.
NOAA and commercial contractors usually survey between 2,000 and 3,000 square nautical miles each year.
NOAA’s hydrographic data ispublicly available from theNational Geophysical Data Center.
EM 1110-2-1003 1 Jan 02
2-2. Civil Works Program Surveying Requirements
Hydrographic surveying support is required throughout most phases of civil works water resource projects. During the early phases of a project, a comprehensive plan should be developed to integrate hydrographic surveying requirements throughout the various stages of a project's life. Procedures for accomplishing this are contained in ER 1110-2-1150, "Engineering and Design for Civil Works Projects."
Hydrographic surveying may be required during any of the five project phases outlined in ER 1110-2-1150: Reconnaissance phase, Feasibility phase, Preconstruction Engineering and Design (PED) phase,
Construction phase, and Operation and Maintenance phase. Most effort is required during the later three phases.
a. Reconnaissance phase. The reconnaissance phase is general in scope, and at this early stage of project development there is normally no requirement (or funding) for field survey effort. Existing maps or charts are normally adequate for developing the preliminary plans that will ultimately lead to an engineering solution.
b. Feasibility phase. The purpose of the feasibility phase is to formulate a solution to address a specific need. The work includes studying potential solutions, evaluating costs and benefits, preparing initial designs, and recommending a plan to solve the problem. Engineering effort during this phase may include hydrographic surveys of project sites. ER 1110-2-1150 contains the following guidance on surveying requirements:
Surveying, Mapping, and other Geospatial Data. Surveying, mapping, and other geospatial data information should be obtained to support all feasibility phase requirements. At this level, existing surveying, mapping, and other geospatial data available through in-house sources or through other federal, county, local, commercial, or private sources may be adequate. Additional information on finding these sources is available in EM 1110-1-2909. The data source, i.e., compilation scale, contour interval, control data and datum, etc., should be verified to assure it meets accuracy requirements to support the level of detail required. Otherwise, new surveying, mapping, and other geospatial data may need to be developed. If sufficiently scaled topography is not available to support the level of detail required, then it shall be developed during the feasibility phase to eliminate the possibility of large quantity errors (e.g., real estate, reservoir volumes, etc.). Detailed guidance on photogrammetric mapping surveys is provided in EM 1110-1-1000. Survey control methods and if possible the actual control points shall be established in the field at this phase of study to avoid rework and errors and to maintain continuity during subsequent phases of the project. Detailed site-specific mapping may be deferred and developed during the PED phase unless it is required to develop an accurate baseline cost estimate. The Geographic Information System (GIS) for the project should be established during this phase in accordance with EM 1110-1-2909 and ER 1110-1-8156.
During the feasibility phase cost estimates for subsequent modeling requirements are made. These would include any tidal modeling requirements, such as on projects without an established MLLW reference. Also, projects requiring RTK DGPS observations will require geoid modeling during the PED phase.
c. Preconstruction engineering and design phase. The Preconstruction Engineering and Design Phase (PED) is the phase during which the design is finalized, the plans and specifications (P&S) are prepared, and the construction contract is prepared for advertising. A Design Documentation Report (DDR) is developed. This phase may involve physical model studies or development of water level or geoid reference models. Hydrographic surveys are a critical component of the P&S. P&S shall be prepared in accordance with ER 1110-2-1200, the Architect/Engineer/Construction CADD Standards and the CADD/GIS Technology Center (Tri-Service) Spatial Data Standards.
d. Construction phase. Hydrographic survey support is continuous throughout construction--especially for dredging and beach renourishment projects. The various surveys supporting construction are described later in this chapter and in subsequent chapters.
e. Operation and maintenance (O&M) phase. Maintenance of authorized navigation projects requires continuous condition surveys and construction surveys associated with maintenance dredging.
bathymetric surveys, multi beam,multi-beam, single beam, pre dredge, post
dredge, conditions survey, shoreline protection, magnetometer, sidescan,
Money and limit line?
From the website
Meridian Surveying Engineering Inc. is a full service hydrographic surveying firm providing high quality surveys under the direct guidance of a Licensed Professional Land Surveyor. We provide the highest quality data that includes both hydrographic data and integrated land data solutions which can include boundary location where applicable. We possess the tools to incorporate High Definition 3D scanning images of the shoreline to the Hydrographic Data with our FARO (Trimble TX5) scanner. We can also provide Independent certification of dredge volumes as required by government agencies to Army Corps Standards.
Our vast experience providing a variety of surveying services means we can provide you with versatile and specific solutions to match your needs.:
Our equipment includes:
Odom CVM Echosounder
FARO High Definition Scanners (FARO ION, Trimble TX5)
Hydrolite (Seafloor Systems)
Trimble R8/R10 RTK GNSS, Base & Rover
Hypack 2013 (Hydrographic Survey Software) for data collection and post processing
Trimble TSC3 data collector with Trimble Survey Controller software
Trimble VX and Trimble S6 Total Stations
Side Scan system
27 foot diesel aluminum John Boat
19 foot Boston Whaler Nantucket ETEC 150
17 foot Boston Whaler Montauk ETEC 90
12 foot launch for shallow water & envirosurveys 4HP ultra low emissions
Our surveys meet the standards of care established by the Army Corps of Engineers. We maintain the highest accuracy and regularly conduct quality assurance checks and tests, giving our clients accurate, reliable results.