Call us:+393282728632


The bathymetric surveys for the morphological development of the marine and lake

The bathymetry is a discipline that deals with the measurement of the depth and the mapping of the seabed.
The bathymetry is a discipline of oceanography and geodesy that deals with the measurement of the depth and the mapping of the seabed. The bathymetric surveys are done so for the the knowledge of the trend of morphological sea and lake bottom.
The bathymetry and the resulting data are necessary for the design and monitoring of maritime and fluvial works, in dredging and beach nourishment and studies for coastal erosion.
The measurements are generally carried out by a vessel equipped with a precision echo sounder, single beam or multi-beam. The location is provided by a GPS receiver. A bathymetric software allows you to follow the major routes and designed to capture data from different instruments.
The coastal bathymetric surveys using single-beam echo sounder is conducted following the contour lines drawn according to the project, placed generally perpendicular to the coast, complemented by additional routes perpendicular to the precedents that are used to control.
The surveys are generally carried out in completely calm seas and no wind. Sounding the sections are covered with a boat moving at low and constant speed along the predetermined routes. Generally are used, for this type of reliefs, small boats from the low draft as should be as close as possible to the shore.
For the bathymetric survey is used provides an automatic-digital data acquisition system with real-time vessel positioning by GPS technology with correction via radio modem coordinates. This system allows to realize the relief of the lines without any alignment and to have instantaneous correction of the shares.
The onboard GPS transmits real-time, at very high frequencies, the coordinates (East, North and interest) to the navigation software.
The operator on the vessel directs the boat following the directions on the computer monitor, where it is indicated the track that represents the theoretical line to be detected and the instantaneous position of the vessel.
Once you reach the vessel in alignment with the section to be detected, the operator is following with the greatest possible precision project line displayed, starting the acquisition of data. They are also visible for the out-route, the speed in knots, the steering angle, the distance from the beginning and from the end of the route, the number of event and other useful values for the pad.
This technology offers significant advantages; calculating the GPS fact, in addition to the coordinates, also the absolute position of the transducer in real time and with centimeter accuracy, it becomes possible, in conjunction with the data fed from, automatically correct all the oscillations of the sea surface (tide, waves, superelevation due to the mass of water pushed by the wind) during the survey.
With this methodology, as seen, there is no need to operate the tidal corrections and atmospheric pressure for the reduction to sea level to rear, in most all the vertical oscillations are automatically taken into account.
Fishfinders used are of catchment type with an accuracy of 1-2 cm. The adopted frequency is generally about 200 KHz; a good compromise to ensure an accurate survey of the seabed with little interference of the water column. The emission cone of the instrument is usually very tight to ensure a high geometrical resolution.
It is required a frequency of at least one pulse (beam) per second. To ensure consistency between the depth measurements and the planimetric, the sounder is placed on axis to the receiver for the planimetric position, or alternatively are calculated relative off set. At the beginning and end of survey was proceed to the sonar calibration. The instrumental speed according to the speed of ultrasound in water is carried out using the method of "Pub Check" (measurement of the depth of immersion of a bar or metal disc fell below the transducer and suspended to a graduated cable).
This is followed by digital correction of any error on the navigation software.
Often for economical problems, in this type of investigation we are not used for motion sensors for the roll and pitch correction and performed the calculation of changes in the share of the translator. By performing a perfectly calm sea surveys, and usually at shallow depths, that attenuates from the geometrical point of view the problem, the error is deemed tolerable. Running the survey directly into digital format all the data is recorded on the onboard PC.
The reliefs by means of single-beam, especially in sandy bottoms, not always required a centimeter accuracy on the position. Often, as seen, they are sufficient DGPS instruments of the sub-meter accuracy for obtaining excellent results.
In this case the tide during the relief is generally measured by reading on a graduated rod, leveled by a known elevation target point, and positioned in calm sea area. Alternatively they use the values from tide gauges.
Technology multibeam M.B.E.S. (Multi Beam Echo Sounding) is very sophisticated and capable of delivering superior quantitative and qualitative standards of the information produced.
With this instrumentation switching from an acquisition for individual points (singlebeam) along the navigation route (traditional echo sounder) to an acquisition continues that uses a high number of beams simultaneously, covering a bottom side band equal to 2:00 to 4:00 times the investigated depth.
The resolution is very high and allows to identify the bottom structure also of small size and track continuity.
Even in this case, the navigation is assisted by a precision GPS RTK mode. Furthermore, to ensure the potential accuracy of the instrument, the motion sensors are required for the compensation of rolling and pitching as well as of a high-precision gyro for the correction of the direction. Permoettono appropriate calibrations also the correction of the acquired data.
This type of acquisition, in addition to allowing a considerable saving of time on large areas, allows to know more accurately the actual morphology of the seabed with the respective bathymetric levels, being obtained, the latter, for direct measurement and not by interpolation (as happens for the data produced by the single beam).
Usually the reliefs provide a total coverage of the survey area that is performed by probing along parallel transects that provide for a stacking of the different sweeps data.
For particular applications MultiBeam the transducer can be mounted in an inclined mode laterally, so as to allow in addition to the relief of the seabed, for example, of the docks and the escarpment of defense works from the foot of the same up to almost the water surface.
The relief in the middle Multibeam, causing higher, is obviously costs used where you want to get a significant detail of the seabed or where the full bottom coverage is required to calculate more precisely the volumetric changes of the sedimentary deposit.
The bathymetry is a discipline of oceanography and geodesy that deals with the measurement of the depth and the mapping of the seabed. The bathymetric surveys are done so for the the knowledge of the trend of morphological sea and lake bottom.
The bathymetry and the resulting data are necessary for the design and monitoring of maritime and fluvial works, in dredging and beach nourishment and studies for coastal erosion.
The measurements are generally carried out by a vessel equipped with a precision echo sounder, single beam or multi-beam. The location is provided by a GPS receiver. A bathymetric software allows you to follow the major routes and designed to capture data from different instruments.
The coastal bathymetric surveys using single-beam echo sounder is conducted following the contour lines drawn according to the project, placed generally perpendicular to the coast, complemented by additional routes perpendicular to the precedents that are used to control.The surveys are generally carried out in completely calm seas and no wind. Sounding the sections are covered with a boat moving at low and constant speed along the predetermined routes. Generally are used, for this type of reliefs, small boats from the low draft as should be as close as possible to the shore.
For the bathymetric survey is used provides an automatic-digital data acquisition system with real-time vessel positioning by GPS technology with correction via radio modem coordinates. This system allows to realize the relief of the lines without any alignment and to have instantaneous correction of the shares.
The onboard GPS transmits real-time, at very high frequencies, the coordinates (East, North and interest) to the navigation software.The operator on the vessel directs the boat following the directions on the computer monitor, where it is indicated the track that represents the theoretical line to be detected and the instantaneous position of the vessel.Once you reach the vessel in alignment with the section to be detected, the operator is following with the greatest possible precision project line displayed, starting the acquisition of data. They are also visible for the out-route, the speed in knots, the steering angle, the distance from the beginning and from the end of the route, the number of event and other useful values for the pad.
This technology offers significant advantages; calculating the GPS fact, in addition to the coordinates, also the absolute position of the transducer in real time and with centimeter accuracy, it becomes possible, in conjunction with the data fed from, automatically correct all the oscillations of the sea surface (tide, waves, superelevation due to the mass of water pushed by the wind) during the survey.
With this methodology, as seen, there is no need to operate the tidal corrections and atmospheric pressure for the reduction to sea level to rear, in most all the vertical oscillations are automatically taken into account.
Fishfinders used are of catchment type with an accuracy of 1-2 cm. The adopted frequency is generally about 200 KHz; a good compromise to ensure an accurate survey of the seabed with little interference of the water column. The emission cone of the instrument is usually very tight to ensure a high geometrical resolution.It is required a frequency of at least one pulse (beam) per second. To ensure consistency between the depth measurements and the planimetric, the sounder is placed on axis to the receiver for the planimetric position, or alternatively are calculated relative off set. At the beginning and end of survey was proceed to the sonar calibration. The instrumental speed according to the speed of ultrasound in water is carried out using the method of "Pub Check" (measurement of the depth of immersion of a bar or metal disc fell below the transducer and suspended to a graduated cable).This is followed by digital correction of any error on the navigation software.Often for economical problems, in this type of investigation we are not used for motion sensors for the roll and pitch correction and performed the calculation of changes in the share of the translator. By performing a perfectly calm sea surveys, and usually at shallow depths, that attenuates from the geometrical point of view the problem, the error is deemed tolerable. Running the survey directly into digital format all the data is recorded on the onboard PC.The reliefs by means of single-beam, especially in sandy bottoms, not always required a centimeter accuracy on the position. Often, as seen, they are sufficient DGPS instruments of the sub-meter accuracy for obtaining excellent results.In this case the tide during the relief is generally measured by reading on a graduated rod, leveled by a known elevation target point, and positioned in calm sea area. Alternatively they use the values from tide gauges.

Technology multibeam M.B.E.S. (Multi Beam Echo Sounding) is very sophisticated and capable of delivering superior quantitative and qualitative standards of the information produced.With this instrumentation switching from an acquisition for individual points (singlebeam) along the navigation route (traditional echo sounder) to an acquisition continues that uses a high number of beams simultaneously, covering a bottom side band equal to 2:00 to 4:00 times the investigated depth.
The resolution is very high and allows to identify the bottom structure also of small size and track continuity.
Even in this case, the navigation is assisted by a precision GPS RTK mode. Furthermore, to ensure the potential accuracy of the instrument, the motion sensors are required for the compensation of rolling and pitching as well as of a high-precision gyro for the correction of the direction. Permoettono appropriate calibrations also the correction of the acquired data.
This type of acquisition, in addition to allowing a considerable saving of time on large areas, allows to know more accurately the actual morphology of the seabed with the respective bathymetric levels, being obtained, the latter, for direct measurement and not by interpolation (as happens for the data produced by the single beam).
Usually the reliefs provide a total coverage of the survey area that is performed by probing along parallel transects that provide for a stacking of the different sweeps data.
For particular applications MultiBeam the transducer can be mounted in an inclined mode laterally, so as to allow in addition to the relief of the seabed, for example, of the docks and the escarpment of defense works from the foot of the same up to almost the water surface.
The relief in the middle Multibeam, causing higher, is obviously costs used where you want to get a significant detail of the seabed or where the full bottom coverage is required to calculate more precisely the volumetric changes of the sedimentary deposit.

Did you enjoy this article?