Gustin, Cothern & Tucker

Land Surveying - Civil Engineering - Hydrographic Surveying - Aerial Surveying
 

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HYDROGRAPHIC SURVEYING 

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WHAT WE DO:
For over two decades, GCT has provided Hydrographic and related surveying services, for the U.S. Army Corps of Engineers, other government agencies and the private sector, these include:
  • Mobile District Corps of Engineers;
    Tuscaloosa Site Office, Panama City Site Office and Irvington Site Office. 

  • Pittsburgh District Corps of Engineers

  • Jacksonville District Corps of Engineers

  • U.S. Fish and Wildlife 

The services provided to the Corps of Engineers include:

HYDROGRAPHIC  CADASTRAL  CONTROL 
Single & Multibeam Beach erosion GPS - Static/RTK
Side Scan Sonar Flood Studies Construction Stakeout
Sub-bottom Profiling Boundary/Topo Horizontal/Vertical

We have completed Hydrographic projects on the following:

Ohio River Allegheny River Monongahela River
Kentucky River Tombigbee River Black Warrior River
Alabama River Mobile River Escatawpa River
Gulf of Mexico Choctawhatchee River Fowl River
Mobile Bay Chickasaw River Coosa River
Beaver River Choctawhatchee Bay Tenn/Tom Waterway

Our recent COE contracts have consisted of, hydrographic surveys in support of dredging activities, dredging quantity computations, geodetic control surveys, boundary surveys, topographic mapping and construction stakeout of upland disposal sites.

  • Some of the major efforts accomplished by GCT in Hydrographic surveying are:
1< Ohio River Navigational Charts: Hydrographic Survey of 112 miles of the Ohio River to update Pittsburgh District Ohio River Navigational Charts.
2< Ohio River Main Stem Study (ORMSS) Multibeam - Class I Hydrographic Survey of 33 miles of Ohio River, for design purposes, and to develop plans and specifications for a proposed dredging and disposal contract.
3< Post Hurricane Georges condition surveys An Emergency Hydrographic survey of 613 cross sections along 26.26 miles of waterway. The effort was completed 10 days after the request was made.
4< Established 200 permanently monumented baselines on the Black Warrior & Tombigee and Alabama River systems.
5< Lake Darling, North Dakota Capacity Survey - Hydrographic Survey and contour mapping for a capacity survey (with our DGPS Hydro System) of a 10,300 acre lake for the U.S. Fish and Wildlife Services Water Resources.
6< Kentucky River Pool 9 Capacity Survey - Hydrographic survey of 20 miles of the Kentucky River for American Water Company and GRW Aerial Surveys, Inc.
7< Support Dredging Activities for the Tuscaloosa Area Office, Mobile District - Contracted to perform Hydrographic, Topographic, construction, control surveys and quantity computations for a total of ten (10) years.
8< Tennessee Tombigbee Waterway from Columbus, Mississippi to the Tennessee State line - Set-up the initial sedimentation ranges and hydrographic surveys.
9< Beach Erosion and Accretion immediately following hurricane Fredrick. Re-established and extended horizontal and vertical control and run cross-sectional surveys along the coast of Alabama to determine beach erosion and accretion.
10< Completed sedimentation ranges and hydrographic surveys for navigation on the Coosa River from Pell City, Alabama to Montgomery, Alabama.
11< Performed hydrographic Surveys and sedimentation ranges for U.S. Army Corps of Engineers lake system. These lakes included: Lake Eufaula, Alabama, West Point Lake, Georgia, Lake Altoona, Georgia and Lake Sidney Lanier, Georgia.
  • AUTOMATED HYDROGRAPHIC SYSTEMS:

    Differential Global Positioning (DGPS):
    GCT has two hydrographic survey systems utilizing Differential Global Positioning System (DGPS). 
    One system broadcasts the  RTCM correction via a Trimble Navigation 4000SE or 4400 GPS Receiver Base Station w/RTCM output and a 35 watt Radio Modem. The radio data link for this system provides a 2 to 6 mile survey radius (depending on terrain). This configuration is primarily for use where the U.S. Coast Guard correction is not available.
    The other system configuration uses a Starlink™ U.S. Coast Guard Radio Beacon Receiver. The Starlink™ receives the U.S. Coast Guard RTCM correction and provides this correction to the ship GPS Receiver. Either the Trimble 4000SE or the 4400 GPS receivers may be used on the boat.
    Both of these systems provide real-time sub-meter accuracies.

    Real-time Kinematic (RTK):
    The RTK system provides a real-time accuracy level of 1 to 3 centimeters in X, Y and Z positions. The use of RTK in Hydrographic surveying provides a vertical reference datum for all depth measurements and eliminates errors introduced from heave, vessel squat, and tidal fluctuations. 
    Precise heading is also provided by the RTK system. This is accomplished by using two Trimble 4400 dual frequency Receivers w/On the Fly Initialization (OTF) on the survey boat. The GPS Antennas are mounted on the bow and stern of the survey boat. Position fixes are updated at 5Hz (5 times per second). This system is ideal for multibeam surveys due to the very accurate heading information. 

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    GCT uses HYPACK™, HYSWEEP™ Hydrographic survey software and Skynet™, GCT's proprietary hydrographic survey software.

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    HYPACK and SkyNet, both provide: navigation along predetermined survey lines, graphical displays of plan and profile views while surveying, real time coordinate conversions, data storage and processing.  This system is also capable of on-board map production of surveyed data.  

    Range Azimuth System:
    GCT's Range Azimuth System, (purchased in 1989), is comprised of the HYDRO I RANGE AZIMUTH SYSTEM linked with our TOSHIBA Laptop Computer. This system provides digital data in X, Y, & Z format at a rate of 0.7 seconds per fix. This data is downloaded directly from the HYDRO I Ship Computer to the Laptop Computer which allows unlimited data storage and field verification of survey data.

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GCT's Hydrographic Equipment:
Sample Multibeam
Hydrographic Data
copyright Gustin, Cothern & Tucker, Inc. 1999
Last revised: February 14, 2003