As obras de Ampliação da Calha do Rio Tietê fazem parte de medidas estruturais que visaram ao aumento da capacidade de vazão para o controle das enchentes na RMSP. A regularidade da capacidade de vazão dependerá, dentre outras ações, de dragagens de manutenção e retirada do material dragado, cuja destinação é bastante problemática. O objetivo deste trabalho é a elaboração de um estudo sobre o processo de dragagem, transporte e disposição final de material de leito de rio por meio da apresentação do processo adotado no estudo de caso: Ampliação da Calha do Rio Tietê Fase II. Para esse fim, são abordados os principais aspectos técnicos, ambientais, sociais e econômicos relativos às obras do estudo de caso, dando ênfase à gestão do sedimento dragado, que busca estar em consonância com as normas e diretrizes legais vigentes. São finalmente enunciadas as principais recomendações e conclusões que devem ser aplicadas na gestão do sedimento dragado do Rio Tietê. / The works of Enlargement of Rio Tietê\'s Gutter (Waterway) are part of structural measures that objective increase the flow capacity for inundation control in RMSP (Metropolitan Region of São Paulo). The regularity of the flow capacity will depend, among other actions, of maintenance dredgings and retreating of dredged material, whose destination is plenty of problem. The aim of this work is the elaboration of a study about the dredging process, transport and final disposition of the river bed sediment through the presentation of the process adopted in the case study: Enlargement of Rio Tietê\'s Gutter Phase II. For that purpose, the main technical, environmental, social and economical aspects related to the works of the case study are discussed, giving emphasis in the administration of the dredged sediment, that seek fitting to the in course norms and legal guidelines. Finally, the main recommendations and conclusions that should be applied in the administration of Rio Tietê\'s dredged sediment are examined.

Effects of 4-inch (10.16 cm) suction dredge mining on benthic macroinvertebrates in 3rd to 4th order streams were investigated in 1996 by evaluating four mining claim operations in Althouse Creek, Sucker Creek, and Taylor Creek in southwestern Oregon's Rogue River basin. The effects were site-specific. The study showed no significant (p>0.05) differences between treatment and control areas in density and species diversity of benthic macroinvertebrates. However, mean taxa richness significantly (p<0.05) increased thirty days following the end of the mining period. Collector-filterers were significantly (p<0.05) lower in dredged areas thirty days after the mining season. Because of constraints in sampling design, sample sizes and relatively small treatment areas, the results from this study are tenuous at best. There were apparent inherent differences in species dominance among sites possibly a result of differences in stream size and riparian conditions. This further confounds results of this study. / Graduation date: 2000

Thesis (M.S.)--Oregon State University, 1977. / Typescript (photocopy). Date thesis presented: June 3, 1976. Includes bibliographical references. Also available on the World Wide Web.

Dredge cutting forces produced by the movement of the cutterhead through the sediment have been measured with the laboratory dredge carriage located at the Haynes Coastal Engineering Laboratory. The sediment bed that was used for the dredging test was considered to be relatively smooth and the sediment used was sand with a d50=0.27 mm. Forces on the dredge carriage were measured using five 13.3 kN (3000 lb) one directional load cells placed on the dredge ladder in various places so the transmitted cutting forces could be obtained. The objectives for this study are to determine the vertical, horizontal, and axial forces that are produced by the cutterhead while testing. So, to find these cutter forces, a static analysis was performed on the carriage by applying static loads to the cutterhead in the vertical, horizontal, and axial directions, and for each load that was applied, readings were recorded for all five of the load cells. Then, static equilibrium equations were developed for the dredge carriage ladder to determine loads in the five load cells. Also, equilibrium equations can be applied to a dredging test to find the cutterhead forces by taking the measured data from the five load cells and applying the known forces to the equations, and the cutterhead forces can be determined. These static equilibrium equations have been confirmed by using a program called SolidWorks, which is modeling software that can be used to do static finite element analysis of structural systems to determine stresses, displacement, and pin and bolt forces. Data that were gathered from the experimental procedure and the theoretical calculations show that the force on the dredge cutterhead can be determined. However, the results from the static equilibrium calculations and the results from the SolidWorks program were compared to the experiment procedure results, and from the comparison the procedure results show irregularities when a force of approximately 0.889 kN (200 lb) or above is applied to the cutterhead in a north, south, west, or east orientation. The SolidWorks program was used to determine the results for displacements of the dredge carriage ladder system, which showed that large displacements were occurring at the location of the cutterhead, and when the cutterhead displaces it means that the carriage ladder is also moving, which causes false readings in the five load cells. From this analysis it was determined that a sixth force transducer was needed to produce more resistance on the ladder; and the cell #1 location needed to be redesigned to make the ladder system as rigid as possible and able to produce good testing results. The SolidWorks program was used to determine the best location where the sixth force transducer would give the best results, and this location was determined to be on the lower south-west corner oriented in the direction east to west. The static equilibrium equations were rewritten to include the new redesigned cell #1 location and the new location of the sixth load cell. From the new system of equations, forces on the cutterhead can be determined for future dredging studies conducted with the dredge carriage. Finally, the forces on the laboratory cuttersuction dredge model cutterhead were scaled up to the prototype 61 cm (24 in) cuttersuction dredge. These scaled up cutting forces on the dredge cutterhead can be utilized in the design of the swing winches, swing cable size, ladder supports, and ladder.

Thesis (M.S.)--University of North Carolina at Wilmington, 2003. / Includes bibliographical references (leaves : [26]-29).

No description available.

Thesis (M.S.)--Ohio University, November, 2001. / Title from PDF t.p.

The present study focuses on the sediment deposition and consequent dredging issues in Lower Ohio River at the Olmsted Locks and Dam area-River mile (RM)-964.4 during the ongoing in-the-wet construction methodology. The study reach is between Locks and Dam 53 (RM 962.6) at upstream, and RM 970 at downstream. One dimensional (1-D) HEC-RAS numerical modeling in conjunction with Arc-GIS was employed. Stream flow measurements, velocity, incoming sediment concentration, bed gradation, and annual hydrographic survey data acquired from public archives of USGS and USACE Louisville District were used as inputs. The model was subjected to the 1-D quasi-unsteady and completely unsteady sediment transport module, available in the latest HEC-RAS 5.0 Beta release. Calibration and validation of the hydrodynamic and sediment models were performed using measured water surface elevation, velocity, and sediment loads at measured sections. Post-model calibration and validation, deposition to excavated cross-sections for future dam shells at Olmsted was predicted, which warrants dredging. The study attempted to analyze the sediment transport trend with the focus on depositionat Olmsted Locks and Dam area using the sensitivity analysis approach of transport capacity functions. Moreover, the capability of 1-D HEC-RAS quasi-unsteady and completely unsteady models were assessed in prediction of sediment deposition in the construction area (dam shells excavation area). A temporal deposition prediction model was developed that can potentially replace the current ad-hoc approach used to determine the dredging schedule. Likewise, a representative environmental risk associated with sedimentation in the study area was examined. The model can potentially be used as a decision support tool to analyze the long term impact of sedimentation in the vicinity of Olmsted Locks and Dam if further updates on the river bathymetry, and specific field data are supplemented to the model.

The thesis provides an integrated review and analysis of strategic scientific information from which management procedures for the environmentally acceptable disposal of dredged materials from Greater Vancouver into the Strait of Georgia are determined. An analysis of reported and suspected contamination of Vancouver's waterways identifies trace metals and hydrophobic organic chemicals that warrant concern by authorities responsible for the management of dredged material disposal. The processes, transformations and pathways of these contaminants in the marine environment subsequent to dredged material disposal are reviewed. It is argued that a really confined degradation of suitable disposal sites is of negligible concern, but that release of contaminants from the disposal area, were it to occur, could have unpredictable and perhaps substantial environmental consequences. The major potential pathway of contaminant release from dredged material during or subsequent to disposal is via the resuspension and transport of fine particulate material. Biological accumulation of contaminants and their transport through the food chain is a potentially significant release pathway for hydrophobic organic contaminants. Biological transformation to more soluble metabolites is also potentially significant for mercury and some of the less chlorinated and lower molecular weight organic compounds of concern. Desorptive release of contaminants from the disposed sediments into solution is usually negligible, with the possible exceptions of cadmium and mercury. A review of the physical factors that promote contaminated sediment erosion and dispersion during or subsequent to dredged material disposal identifies oceanographic characteristics where such release will be minimal. There are only four areas within the Strait of Georgia that exhibit these characteristics. Two of these areas are adjacent to valuable and sensitive biological resources and are consequently unsuitable as ocean dumping sites. Dredged material disposal at the other two sites, one near Smelt Bay, Cortes Island, and the other off McNaughton Point, Sechelt Peninsula, should result in minimal adverse environmental impact. Available methodologies to identify dredged materials with contaminant levels that preclude their environmentally acceptable disposal at these recommended sites are discussed. / Science, Faculty of / Resources, Environment and Sustainability (IRES), Institute for / Graduate

The principles of placer mining, no matter what the type, are the same. A device such as a pan, sluice, or a dredge is used in combination with water to extract the gold. from the material in which it was deposited. Likewise, the motive for all types of placer mining was the same; to obtain the most gold with a minimum of costs. Dredging is the most recent method used in California to mine placer deposits. The question of primary concern surrounding this seemingly profitable industry is: Why did gold dredging come to a grinding halt in 1968? Lesser concerns are: What impact did it have on the state in terms of' economics and aesthetics? Is it possible that dredging for gold could possibly be renewed in the State?