Search

In a coastal environment, this paper investigated the formation process and the cumulative shape of subaqueous mounds formed by hopper dredged discharges. Hydrological observations and field tests were performed to examine the flow features and ultimately generated morphology characteristics. A high-precision digital elevation model (DEM) was established by multi-beam depth sweeping (MBDS) in the experiment. Particular attention was paid to the formation of the mounds, the three-dimensional shape and the influence factors. The field measurements showed that the mounds were roughly symmetrical in space, and the tidal current, though of weak strength, played a certain role in shaping the profiles. Cone and volcanic cone mound tops were observed, featuring the main top shapes. The height and covered area of the mounds were proportional to the amount of dumped sediment, and they were also affected a lot by the water depth. The results of superimposed tests showed that the second placement over the existing mound resulted in a similar overall shape, but there was pronounced movement around the mound; additional discharged volumes at the same location mainly increased the mound height. The field tests provided a reference for understanding the sediment dumping in other similar coastal areas. Validerad;2020;Nivå 2;2020-07-09 (johcin)

Three-dimensional hydraulic modeling of Detroit River was carried out using the Curvilinear Hydrodynamics in 3-D (CH3D) Model. A 2-D grid scheme was constructed by using SMS software along Detroit River from Lake St. Clair to Lake Erie with the two banks as the transversal boundaries. The water depth (vertical &sgr;--) was divided into 10 layers from water surface to the river bottom. A modification to the program was made to enable flexible Manning roughness by applying the Strickler formula. The National Oceanic and Atmospheric Administration (NOAA) USA bathymetry data, collected between April 17 and August 8 of 2000, were post-processed for water level corrections using MapInfo software. The data were also extended to areas where there were no NOAA measurements in the Detroit River basin. Relatively steady flow recordings in the period of August 3--4th, 1998 were selected for the simulation among four periods of data collection. Six water level gauge records in various locations were used to check the theoretical water level computations. Twenty-four cross sections of Acoustic Doppler Current Profiler (ADCP) velocity measurements were also post-processed to sort the measured points to the computational grid and used to compare the accuracy of CH3D model output in the same flow period. Comparison between computed velocities and velocity measurements at various transects shows a good agreement typically below 15% error, and comparison between the computational water surface elevation versus that of records in gauge stations is also a good agreement.Dept. of Civil and Environmental Engineering. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2001 .D34. Source: Masters Abstracts International, Volume: 40-06, page: 1572. Adviser: Stanley Reitsma. Thesis (M.A.Sc.)--University of Windsor (Canada), 2001.