scholarly journals River bed classification using multi-beam echo-sounder backscatter data

10.3990/2.245 ◽  
2012 ◽  
Author(s):  
Niels Kinneging ◽  
Mirjam Snellen ◽  
Dimitrios Eleftherakis ◽  
Dick Simons ◽  
Erik Mosselman ◽  
...  
Keyword(s):  
River Bed ◽  
Echo Sounder

scholarly journals Determination of a Section of Woji Riverbed Depths for Safe Navigation

2017 ◽  
Vol 1 (1) ◽  
pp. 55-68
Author(s):  
A. U. Ekpa ◽  
N. I. Eyakndue
Keyword(s):  
Google Earth ◽  
Quality Of Data ◽  
Navigation Data ◽  
Safe Navigation ◽  
River Bed ◽  
Profile View ◽  
Tidal Data ◽  
Elevation Changes ◽  
Average Variation ◽  
Echo Sounder

The depths of the oceans, seas, rivers, etc. and charting the shape and topography of the ocean floor are only determined though bathymetric processes. And mariners primarily depend on water depths beneath their vessels for safe navigation. Bathymetry also goes a long way to enhance the identification of possible features on the seabed such as elevation changes, rock outcrop, wreckages, sunken vessels, pipeline, or any other obstructions that could cause hazard to navigation. This study employs the bathymetric principles to determine river-bed depths of a section of the Woji River for the purpose of creating a two-dimensional view of the underlying sub-surface and a threedimensional model of the river-bed, to enhance safe navigation. Data acquisition was done using satellite imagery from Google Earth, total tide prediction data, sounding depths using Midas echo sounder and GPS data. Data processing performed on observed bathymetric data include spike removal, tidal correction on instantaneous depths. The processed depths were analysed and presented in form of profile view, graphs, and charts. A flow and sedimentation simulation was carried out using ArcGIS 10.3, to show the nature of the river. The tidal data aided in sounding reduction, and river average depth of 6.022m was obtained. The levelling mis-closure was 0.001m and the average variation in echo sounder calibration was 0.08m. Based on the acquired and output data, the produced chart revealed sedimentation effect on the convex coastline, uneven riverbed topography possibly due to sand excavation, which could pose serious danger to the safety of navigation. Based on these results, the use of Sub-Bottom Profiler and a Multi-Beam Echo Sounder (MBES) is therefore recommended in order to improve the quality of data obtained.

QUANTIFICATION OF TUNA FISH TARGET STRENGTH USING QUANTITATIVE ECHO SOUNDER

2009 ◽  
Vol 1 (1) ◽  
Author(s):  
Henry M. Manik
Keyword(s):  
Wave Reflection ◽  
Fork Length ◽  
Research Programme ◽  
Yellowfin Tuna ◽  
Target Strength ◽  
Bigeye Tuna ◽  
Tuna Fish ◽  
Thunnus Obesus ◽  
The Relationship ◽  
Echo Sounder

A preliminary research programme was carried out in order to study the acoustic wave reflection or target strength (TS) of tuna fish using a quantitative echo sounder (QES). The relationships between TS to fork length (FL) and swimbladder volume, for bigeye tuna (Thunnus obesus) and yellowfin tuna (T. albacares) are investigated. The TS of bigeye tuna was about 3 dB higher than yellowfin tuna when comparing species at the same size. The result can be correlated to the swimbladder volume differencebetween species. The relationship between TS and swimbladder volume was quantified for both species.Keywords: tuna fish, target strength, quantitative echo sounder

Distribution of nitrifying bacteria in a shallow stream

1997 ◽  
Vol 36 (8-9) ◽  
pp. 161-166 ◽  
Author(s):  
Ivana Jancarkova ◽  
Tove A. Larsen ◽  
Willi Gujer
Keyword(s):  
Field Experiments ◽  
Heterotrophic Bacteria ◽  
Pollution Source ◽  
Nitrifying Bacteria ◽  
Channel Water ◽  
River Bed ◽  
Hydraulic Conditions ◽  
Major Floods ◽  
Shallow Stream ◽  
Stream Bed

A project investigating the dynamics of self-purification processes in a shallow stream is carried out. Effects of the concentration gradient due to the distance to the pollution source, of hydraulic conditions in the river bed and of storm floods on the distribution of nitrifying bacteria were studied with the help of laboratory and field experiments. Nitrifiers density on the surface of the stream bed increased rapidly up to a distance of 300 m from the WWTP indicating possible competition of the nitrifiers with the heterotrophic bacteria close to the WWTP. Afterwards a slight decrease in the downstream direction was observed. In vertical profiles, higher bacterial densities were found at sites with rapid infiltration of channel water to the stream bed than at sites with no exchange between channel water and stream bed water or where stream bed water exfiltrated. A major flood event scoured the nitrifiers nearly totally from the surface of the river bed. Major floods belong so to the most dominant processes controlling self-purification in shallow streams. Minor floods, however, don't scour bacteria in the depth of the stream bed that could then be important for the self-purification processes.

Registration of Airborne LiDAR Bathymetry and Multibeam Echo Sounder Point Clouds

2021 ◽  
pp. 1-5
Author(s):  
Xiankun Wang ◽  
Fanlin Yang ◽  
Hande Zhang ◽  
Dianpeng Su ◽  
Zhiliang Wang ◽  
...  
Keyword(s):  
Point Clouds ◽  
Airborne Lidar ◽  
Airborne Lidar Bathymetry ◽  
Echo Sounder

Predicting river bed substrate cover proportions across New Zealand

CATENA ◽  
2018 ◽  
Vol 163 ◽  
pp. 130-146 ◽  
Author(s):  
Arman Haddadchi ◽  
Doug J. Booker ◽  
Richard J. Measures
Keyword(s):  
New Zealand ◽  
River Bed

scholarly journals Effects of a scientific echo sounder on the behavior of short-finned pilot whales (Globicephala macrorhynchus)

2017 ◽  
Vol 74 (5) ◽  
pp. 716-726 ◽  
Author(s):  
Nicola Quick ◽  
Lindesay Scott-Hayward ◽  
Dina Sadykova ◽  
Doug Nowacek ◽  
Andrew Read
Keyword(s):  
North Carolina ◽  
Generalized Estimating Equations ◽  
Marine Mammals ◽  
Hidden Markov ◽  
Experimental Conditions ◽  
Cape Hatteras ◽  
Consistent Increase ◽  
Pilot Whales ◽  
Acoustic Recording ◽  
Echo Sounder

Active echo sounding devices are often employed for commercial or scientific purposes in the foraging habitats of marine mammals. We conducted an experiment off Cape Hatteras, North Carolina, USA, to assess whether the behavior of short-finned pilot whales (Globicephala macrorhynchus) changed when exposed to an EK60 scientific echo sounder. We attached digital acoustic recording tags (DTAGs) to nine individuals, five of which were exposed. A hidden Markov model to characterize diving states with and without exposure provided no evidence for a change in foraging behavior. However, generalized estimating equations to model changes in heading variance over the entire tag record under all experimental conditions showed a consistent increase in heading variance during exposure over all values of depth and pitch. This suggests that regardless of behavioral state, the whales changed their heading more frequently when the echo sounder was active. This response could represent increased vigilance in which whales maintained awareness of echo sounder location by increasing their heading variance and provides the first quantitative analysis on reactions of cetaceans to a scientific echo sounder.

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