A study of beach profiles and sediment activity has been undertaken investigating natural beaches of inner coastal southwest British Columbia and published data on laboratory beaches. Two separate types of sediment activity are focused upon: longshore sediment, activity occurring on inner coast beaches and on- offshore sediment activity occurring on wave Hume constrained laboratory beaches. Field investigative work on twenty-five natural beaches has included review of past-field studies, profile surveys, sediment tracing experiments, investigation of surface and subsurface sediment, size distribution and structure, measurement of slopes and elevations of shoreline features, review of available wave climate data and wave hindcasting for the period of profile surveys. The work has shown that inner coastal beaches are predominantly shingle beaches or cobble armoured beaches with longshore sediment transport, occurring in a narrow upper foreshore zone under wave action at high tides. There is also evidence that coarse materials (gravels and cobbles) move selectively in an onshore direction and fine materials (silts and sands) move in an offshore direction. The sediment transport processes and beach characteristics identified are different from the summer/ winter beach process known to occur on open coasts. Laboratory beaches have been studied to identify the general response of a beach profile to waves. One problem in the study of beaches has been the lack of a readily measured variable to interrelate wave action and sediment movement. By studying laboratory beach profiles a variable representing on-offshore sediment, movement has been abstracted as an area swept out by differencing two profiles as a function of time. The variable has been investigated using laboratory beach data and correlation between it and wave parameters such as height, and period is evident. A dimensional analysis of on-offshore sediment transport is performed using the swept, area variable. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

M.Sc. / Sediment analysis, especially for trace metals, is important since aquatic sediments act as sinks for metals in the environment. Total element analysis yields insufficient information on the bioavailability and the geochemical fate of these metals. Sequential extraction procedures were developed to determine the partitioning of metals in sediment phases. The need for comparability of data produced world-wide led to the development of a sequential extraction procedure, which was proposed by the Community Bureau of Reference as a standard procedure (refered to as the BCR protocol). We contributed to the validation of the BCR procedure by using well-defined in-house model sediments. The results obtained for the model sediments showed that the BCR procedure could distinguish effectively between anthropogenically introduced metals and metals that form part of the mineral structure of the sediment components. The BCR procedure was applied to the sediments of the Vaal Dam and its contributing rivers. The amount of metals extracted in the first three steps of the sequential extraction procedure were low, indicating a very small contribution of anthropogenically introduced metals. It was therefore concluded that these sediments were relatively unpolluted compared to water systems in, for example, Europe.

No description available.

Erosion, transportation, and deposition of sediment into receiving waters can have substantial environmental and economic impacts. Sedimentation basins are a remediation technique used to limit sediment transport from earth disturbance activities. Retention efficiency is used as a measure of a sedimentation basin's effectiveness. Several factors influence retention efficiency including the type of principal spillway used. The most common spillway is the perforated riser which dewaters the basin throughout its entire vertical profile. However, a relatively new outlet device, the skimmer, has been developed, which dewaters the basin from the water surface. A laboratory study was conducted to compare the skimmer with the perforated riser for three different soil types and determine if there were any significant differences in the trapping efficiencies of the two outlets. The test basin dewatered over a three hour period. The parameters observed were dewatering rate, effluent sediment concentration, sediment loss rate, and retention efficiency. The skimmer treatments consistently had higher values of sediment retention efficiencies. A statistical analysis performed on the retention efficiency data showed that retention efficiency was not influenced by any combination of outlet and soil type and that outlet was significant at the 5% level. Overall, the skimmer outperformed the perforated riser for all soil types tested. Additionally, retention efficiencies were predicted for shorter dewatering times. The results indicated shorter dewatering times may have smaller impacts on the retention efficiency of basins where the skimmer is utilized rather than the perforated riser. / Master of Science

Bibliography: pages 131-139. / The construction of bridge embankments and other physical obstacles in estuaries has often resulted in the redistribution of sediments, which ultimately leads to detrimental impacts in these environments. The aim of this study is to investigate how the sediment distribution and dynamics within a specific estuary, the Uilkraals estuary, have been affected by human disturbance; focusing on the impacts arising from construction of two temporary embankments and a permanent bridge and embankment. The Uilkraals estuary is situated in the south-western Cape, approximately 60 kilometres north-west of Cape Agulhas. Human impact has been extensive and engineering projects of various sizes and permanence have marked the recent history of this estuary. A bridge and embankment which cross the estuary 800 m from the mouth were built in 1973. In 1978 an embankment was built between the bridge and the estuary mouth. A second embankment which replaced the first in 1980, was removed before the end of that year. Extensive dune reclamation occurred on the left bank between 1938 and 1973. The techniques used in the study include: (i) a quantitative analysis of all available aerial photographs from 1938 to 1987 (ii) a ground survey and (iii) core and surface sediment sampling. The quantitative analysis reveals that the major changes in estuarine characteristics have been in response to human disturbance. The contour map and cross-sections drawn from the ground survey indicate a build-up of sediment downstream of the bridge and scouring of the channel upstream. The latter suggests the dominance of the flood-tidal current in the estuary. The core sediment analyses are unable to distinguish any real difference in the modes of sediment deposition on either side of the bridge embankment. The embankment has, however, affected deposition by acting as a "hydraulic shelter" to sediment accumulated downstream of the bridge during high run-off events and by initiating deposition of sediment upstream of the embankment. The surface sample analyses indicate that there has been an increase in flow velocities in the vicinity of the bridge since its construction and that the major agents which bring marine sediment into the estuary are flood-tidal currents and wind. It is concluded that the sediment distribution and dynamics of the Uilkraals estuary have been affected by human disturbance. Recommendations for future management of the estuary are that no further embankments should be constructed in the estuary and that the construction of a culvert or culverts under the existing bridge embankment would alleviate a number of problems presently experienced in the estuary.

The purpose of this work is to generate a shore profile algorithm to be used in estuaries dominated by fine sediments. Numerical models are continually evolving to enhance the overall accuracy of results. However, the typical shore profile is defined as a vertical wall. This work defines the shore as a nonlinear profile which will provide more realistic models. A variety of shore profile equations were examined and tested against a field site, Weeks Bay, Alabama. The most applicable, an equation by S. C. Lee, was modified in order to calculate the entire shore profile length. The distance from the land-water interface to the depth at which sedimentation is negligible can now be modeled with a single equation. Recommendations for the practical aspect of implementation into a numerical model are also considered.

No description available.

No description available.

No description available.

<p> In spite of the difficulties involved in molecular and cellular studies of antibiotic-free cultures of primary human cells, investigations of the sedimentation and survival properties of cell cultures derived from Xeroderma Pigmentosum patients were successfully carried out. Emphasis was on the cellular and molecular effects of ionizing radiation; however preliminary data for cell survival after exposure to UV was obtained.</p> / Thesis / Master of Science (MSc)