Topic
Dredging
About: Dredging is a research topic. Over the lifetime, 3300 publications have been published within this topic receiving 28325 citations.
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TL;DR: Dongting Lake is chosen as the "most affected" lake in China, to assess short-term effects of sand dredging on key environmental parameters and on the structure of the macroinvertebrate assemblage.
49 citations
TL;DR: It is concluded that maintaining the gravel content of surface sediments after dredging and, where practicable, locating extraction sites in areas of higher natural disturbance will minimise the potential for long-term negative impacts on the macrofauna.
48 citations
01 Sep 2003
TL;DR: A hydraulic clam dredging experiment was conducted on a deep offshore sandy bank on the Scotian Shelf in order to examine the immediate impacts of hydraulic dredging on physical habitat and to follow processes of recovery over a 3-year period as discussed by the authors.
Abstract: A hydraulic clam dredging experiment was conducted on a deep (70–80 m) offshore sandy bank on the Scotian Shelf in order to examine the immediate impacts of hydraulic dredging on physical habitat and to follow processes of recovery over a 3-year period. Seabed structural complexity in this low-relief habitat consists of small-scale sedimentary features including pits and bivalve burrow openings as well as polychaete tubes and empty mollusc shells. The most obvious effect of dredging was a dramatic change in seabed topography due to the numerous deep (20 cm), wide (4 m) curvilinear furrows that were cut by the dredges. The loss of burrows, tubes, and shells through destruction or burial, and local sedimentation created a smooth surface. Both spatial scale and sampling resolution were critical in identifying longer-term impacts. Dredge furrows were no longer visible in video 1 year after dredging due to their low relief; however, they persisted, while undergoing changes, as evidenced in sidescan sonograms. The margins of furrows were gradually degraded, likely through the combined actions of slumping, sediment transport and bioturbation. Over time, dredge furrows act as traps for empty shells. Differences in patterns of acoustic reflectance between dredge furrows and the surrounding seabed indicate long-lasting effects on sediment structure. Densities of large burrows were reduced by up to 90% after dredging with no signs of recovery after 3 years due to the high mortalities of their architect, the propellerclam, Cyrtodaria siliqua . Dredging effects were detectable against a background of natural temporal (annual) and large-scale spatial variability in physical habitat.
47 citations
TL;DR: In this paper, the authors present a biological and physical monitoring program to evaluate long-term impacts from sand dredging operations in the United States Outer Continental Shelf (OCS) in order to reduce environmental damage associated with longterm and large-scale use of these resources.
Abstract: NAIRN, R.; JOHNSON, J.A.; HARDIN, D., and MICHEL, J., 2004. A biological and physical monitoring program to evaluate long-term impacts from sand dredging operations in the United States Outer Continental Shelf. Journal of Coastal Research, 20(1), 126‐137. West Palm Beach (Florida), ISSN 0749-0208. The Minerals Management Service (MMS) International Activities and Marine Minerals Division is charged with management of Federal Outer Continental Shelf (OCS) sand and gravel resources that would be used for beach nourishment to repair storm damage and protect against sea-level rise. To reduce environmental damage associated with long-term and large-scale use of these resources, a project was funded by MMS to design a comprehensive physical and biological monitoring program for sand-mining activities. An initial task of this project was performance of a literature review to determine where information gaps existed regarding the effects of sand mining and which physical processes and biological resources should be the focus of monitoring. Based upon the literature review and a conference with other investigators, the monitoring program was designed to include the following elements: benthic communities and their trophic relationships to fishes, marine mammals and wildlife (operational monitoring), sediment sampling and analysis, wave monitoring and modeling, bathymetric and substrate surveys, and shoreline monitoring and modeling. Protocols were developed for these elements to ensure consistency of methods among studies. The two primary physical impacts of concern are changes to the sea bed resulting in changes to the erosion and sedimentation processes along the shore and changes to the sea bed that would have a direct and significant impact on the biological environment. The most important biological impacts from dredging to be monitored in this program are changes in benthic secondary production and trophic transfer to fishes.
47 citations