8/25/2023 0 Comments Define dredgedLevel of mortality or other end point demonstrated by a group of organisms that have been affected by the properties of a substance, such as contaminated water, sediment, or dredged material. The term includes sand, silt, and clay particles as well as other solids, such as biological material, suspended in the water column. Organic or inorganic particles that are suspended in water. The term “dredged material” refers to material which has been dredged from a water body, while the term “sediment” refers to material in a water body prior to the dredging process. Sediment input to a body of water comes from natural sources, such as erosion of soils and weathering of rock, or as the result of anthropogenic activities, such as forest or agricultural practices, or construction activities. Material, such as sand, silt, or clay, suspended in or settled on the bottom of a water body. Placement of dredged material in rivers, lakes, estuaries, or oceans via pipeline or surface release from hopper dredges or barges, without confinement. Typical coastal habitats include beaches, marshes, rocky shores, bottom sediments, mudflats, and the water itself. An organism’s habitat provides all of the basic requirements for the maintenance of life. The specific area or environment in which a particular type of plant or animal lives. Dredging is also conducted for construction purposes, for mining, and for environmental cleanup and enhancement. “Dredging” is the term given to removal by digging, gathering, or pulling out materials from the bed to deepen waterways and to create harbors, channels, and berths. Underwater excavation is called dredging. The term “sediment” refers to material on the bed of a water body prior to the dredging process. The term “dredged material” refers to material which has been dredged from a water body and disposed in a disposal site. Material excavated from fresh, estuarine, or ocean waters. Contaminated sediment or contaminated dredged material:Ĭontaminated sediments or contaminated dredged materials are defined as those that may cause an unacceptable adverse effect on human health or the environment. Other terms used for CDFs that appear in the literature include “confined disposal area,” “confined disposal site,” and “dredged material containment area.” Contaminant:Ī chemical or biological substance in a form that can be incorporated into, onto, or be ingested by or harm aquatic organisms, consumers of aquatic organisms, or users of the aquatic environment. Confined disposal facility (CDF):Īn engineered structure for containment of dredged material consisting of dikes or other structures that enclose a disposal area above any adjacent water surface, isolating the dredged material from adjacent waters during placement. This paper provides an overview of the capital dredging at the Port of Townsville, with emphasis on geological setting, geotechnical investigations, capital dredging requirements, bathymetry, dredging methods/plant and dredged material placement options.Placement or use of dredged material as resource materials in productive ways, which provide environmental, economic, or social benefits. In accordance with relevant state and commonwealth regulations, the capital dredging material derived from the Port of Townsville may be placed at a designated ocean site or brought ashore for land reclamation. To ensure the safety of the surrounding environment, the Port of Townsville has implemented integrated proactive approaches that consider environmental matters from capital dredging project planning and design stages. While necessary to support the economic growth of the region, major port development works such as capital dredging have the potential significantly impact on the natural environment. To determine the technical parameters of quantity, quality and types of materials to be dredged, the Port of Townsville undertakes hydrographic survey offshore geophysical and geotechnical investigations that define dredging projects. The port's capital dredging campaigns over the last 40 years has enabled deepening and widening of the existing inner harbor basin and approach channels, beside development of outer harbor. In order to improve navigational safety and operational efficiency of vessels and to cater for larger ships with deeper draughts, the Port of Townsville conducts capital dredging.
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