Determination of Survey Boat “Heave” Motion with the Use of RTS Technique

Author(s):  
Dariusz Popielarczyk

The paper presents analysis of determination of vertical movement of the surveying boat called “heave” with the use of Robotized Total Station (RTS) technique. The classical geodetic Total Station was used for sub-centimeter calculation of water level changes during hydroacoustic measurements on the fragment of Vistula river behind the dam and hydropower in Włocławek in Poland. The power station work causes up to 1.7 m movement of vertical reference water surface in aspect of local bathymetric survey. The experimental, hydrographic surveys on the river were conducted where the water level was changing significantly over time depending on the operational schedule of the power plant. Verified hydrographic data had to be brought to the common water level. To determine the final water level, data on the height of the Robotized Total Station prism positioned on the boat during sounding was considered. The RTS technique with 0.02–0.05 m vertical accuracy proved to be very useful and essential in engineering inland bathymetric measurements.

Author(s):  
Philippe Maillard ◽  
Évelyn M. Pôssa ◽  
Marília F. Gomes ◽  
Lília M. Oliveira ◽  
Ramille Araújo Soares de Paula ◽  
...  

1979 ◽  
Vol 16 (3) ◽  
pp. 647-668 ◽  
Author(s):  
A. Lambert ◽  
P. Vaníček

Our present knowledge of the patterns and causes of contemporary aseismic movements of the crust in Canada is reviewed. Modern and paleo water-level data and geodetic relevelling data are being used to delineate the regional pattern of vertical movements, but equivalent data on regional horizontal movements are not yet available. The first steps are being taken to relate the emerging regional pattern of vertical movement in Canada to the interactions on the western margin of the America plate and to the spatial variations in seismicity, gravity field, and crustal stress in the plate interior. Viscoelastic modelling of the earth's response to surface loads, and laboratory-based results on possible non-linear rheologies in the mantle have provided a useful theoretical framework for comparing new data on ice-sheet histories with paleo water-level results. Local-scale crustal deformations are being monitored by triangulation, levelling, and gravity networks, as well as by tiltmeters, strainmeters and well-water-level meters. The interpretation of the local deformation data has been facilitated by modelling of the response of inhomogencous-elastic and porous-elastic media. The level of research activity on local aseismic movements in different areas of Canada corresponds to the seismotectonic significance of the areas.


1970 ◽  
Vol 37 ◽  
pp. 1-24
Author(s):  
Zvonimir Haman ◽  
Lars Jørgen Andersen

The purpose of this paper is to present a more reliable calculation of hydraulic properties (T) and (S) utilizing recovery data instead of residual drawdown data. A useful formula for the computation of the recovery from the extrapolated drawdown is recommended. Practical data for this paper has been obtained from a pumping test in an artesian aquifer at Hvinningdal, Silkeborg, Denmark. The calculations are made by means of the nonequilibrium formulas of Theis and Jacob. In addition, the paper provides procedure and examples of adjustments of water-level data for barometric efficiency.


2012 ◽  
Vol 63 (7) ◽  
pp. 616 ◽  
Author(s):  
T. Riddin ◽  
J. B. Adams

Temporarily open/closed estuaries (TOCEs) shift between abiotic states associated with mouth status. The aim of this study was to assess whether macrophyte states could be identified based on the dominant cover abundance of different species representative of specific habitats. A 5-year dataset of monthly macrophyte cover was assessed for the East Kleinemonde Estuary in South Africa. Three macrophyte states were identified: namely open and tidal (predominantly intertidal salt marsh); closed and low water level (predominantly salt marsh); and closed and high water level (with submerged macrophytes). The threshold water level for the change from salt marsh to submerged macrophytes was 1.6 m above mean sea level (amsl). A fourth state where macroalgae were dominant was identified for high salinity conditions (above 30 PSU). It was then possible to examine simulated water level data for different inflow scenarios to determine how often these macrophyte states occurred. Available macrophyte habitat was also calculated for different water levels using a spatial model written in Modelbuilder (ArcGIS 9.3.1). Both methods used to predict available macrophyte habitats are rapid, requiring only information on the elevation range of the main habitats, as well as present distribution and bathymetric maps. These predictive techniques are useful in the determination of the ecological water requirements of small estuaries.


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