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Application of the hydroacoustic methods to the detailed determination of the seafloor condition in the area of roadsteads and anchorages

100%

Rudowski S., Gajewski G. L., Gajewski L., Jezionek J. E., Jezionek E.

2000

vol. 29

issue 3

85-92

The detailed study of the bottom condition of the Anchorage No. 3 of the Gdynia roadstead is presented. The study applies the integrated system of the modern hydroacoustic methods (mainly a multi-beam echosounder, side-scan sonar and subbottom profiler). Results of the hydroacoustic recordings were interpreted using data from grab and core samples as well as a floor inspection done by ROV system of the underwater TV. The morphology and character of the bottom were recognised thoroughly including effects of the human activity (dredging, trace of anchors, presence of anthropo-genic objects etc.). The digital bathymetric map and the map of surface sediments of the bottom test field were prepared. The bottom condition was determined as the area of the gravitational sedimentation of silty-clayey sediments, which have strongly changed anthropogenicly to the depth of 0.5-1.0 metre below bottom level. The obtained results point to the high efficiency of the applied research method. The conducted manner of recording, together with adequate calibration and equipment adaptation to the local conditions allow applying the methodology to future routine studies of the sea bottom for determination its condition. Also, a valuable cognitive material related to the geological structure of the bottom was collected.

Sea relation between a sea depth detected by acoustical methods and a nautical depth

86%

Gajewski L., Morgas M. W., Morgas W., Relisko R. J., Relisko J., Tegowski T. J., Tegowski J.

2000

vol. 29

issue 3

67-84

On twelve testing fields located in the main water basins of the Gda?sk and Szczecin harbours, the efficiency of a new depth technique was verified. The technique that determines a safe nautical depth is defined by a density criterion of a mud-water medium. The measuring results of the medium density varied greatly depending on a physical phenomenon applied in the measuring equipment. The differences found are mainly attributed to a different gas content in the surface mud sediments as well as to reological properties of the sediments. The results of the numerical simulation of acoustic waves propagation in the mud sediments clarify a depth overestimating by the echo sounder of a low frequency.

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2 Oceanological Studies

2 2000

2 Gajewski L.

1 Gajewski G. L.

1 Jezionek E.

1 Jezionek J. E.

1 Morgas M. W.

1 Morgas W.

1 Relisko J.

1 Relisko R. J.

1 Rudowski S.

1 Tegowski J.

1 Tegowski T. J.

Search results

Application of the hydroacoustic methods to the detailed determination of the seafloor condition in the area of roadsteads and anchorages

Sea relation between a sea depth detected by acoustical methods and a nautical depth