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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Patent•
17 Sep 2008
TL;DR: In this paper, a determining method for polluted water bed mud environmental protection dredging depth, comprising analyzing and evaluating the releasing risk and ecological hazard risk of the pollutant at different layer side of the mud based on the vertical distribution of the contaminant in the bed mud by researching the relation of the releasing of bed mud pollutant nitrogen, phosphor or the like and the corresponding pollutant content and the ecological hazard evaluation corresponding with the content of the bed-mud pollutant containing heavy metal, was provided.
Abstract: The invention provides a determining method for polluted water bed mud environmental protection dredging depth, comprising analyzing and evaluating the releasing risk and ecological hazard risk of the pollutant at different layer side of the mud based on the vertical distribution of the pollutant in the bed mud by researching the relation of the releasing of bed mud pollutant nitrogen, phosphor or the like and the corresponding pollutant content and the ecological hazard evaluation corresponding with the content of the bed mud pollutant containing heavy metal; and determining the bed mud dredging depth based on the divided corresponding risk grade. After dredging, the anticipated release rate of the key pollutant such as nitrogen, phosphor at the new surface layer of bed mud-hydrosphere achieves or exceeds a release intensity threshold and the latent ecological hazard index of the heavy metal at the new surface layer of bed mud achieves or exceeds a hazard threshold, therefore the basis of the dredging depth is determined.
17 citations
Journal Article•
TL;DR: In this article, the authors evaluated the potential of associated bed material changes to impact water column concentrations of atrazine, metolachlor, and glyphosate, and found that the bed sediments remaining after dredging, which had coarser texture and lower organic matter, may contribute to overall higher water herbicide levels in the short term by removing significantly less glyphosate from contaminated water and contributing marginally higher sustained levels of herbicide to uncontaminated water.
Abstract: In artificially drained agricultural areas, dredging of drainage ditches is often necessary to ensure adequate field drainage. Stream-simulator (fluvarium) experiments were performed to evaluate the potential of associated bed material changes to impact water column concentrations of atrazine, metolachlor, and glyphosate. In the first experiments, water having high herbicide concentrations flowed across bed sediment collected from a ditch immediately before or after dredging. Afterward, water having initially zero herbicide concentrations flowed across these sediments. Results indicate that the bed sediments remaining after dredging, which had coarser texture and lower organic matter, may contribute to overall higher water herbicide levels in the short term by removing significantly less glyphosate from contaminated water and contributing marginally higher sustained levels of herbicide to uncontaminated water, applicable where sediments exhibit similar dredging characteristic effects. In this case, dredging when herbicide levels are expected to be lowest can help minimize increased transport of some herbicides.
17 citations
01 Dec 1998
TL;DR: In this article, the potential economic impacts that result from compliance with requests for environmental windows (i.e., temporal constraints) on dredging operations are described, when examined in tandem with characterizations of the frequencies of windows associated with Federal dredging projects and the technical issues used to justify requests for specific environmental windows.
Abstract: : This technical note describes potential economic impacts that result from compliance with requests for environmental windows (i.e., temporal constraints) on dredging operations. The primary purpose of this effort was not to quantify the exact total cost attributable to environmental windows throughout the U.S. Army Corps of Engineers (USACE) dredging program, but rather to estimate incremental costs of windows compliance across a spectrum of dredging project scenarios. The information contained herein, when examined in tandem with characterizations of the frequencies of windows associated with Federal dredging projects and the technical issues used to justify requests for specific environmental windows (Reine, Dickerson, and Clarke 1998), is intended to support decisions regarding prioritization of directions of future research.
17 citations
TL;DR: In this paper, the authors analyse differences in abundance, the number of taxa present, diversity, and evenness within sections of dredge-tracks in a disturbed, fished area and a non-fished area along the southern coast of Portugal.
17 citations
TL;DR: Changes in turbidity, sedimentation and light over a two year large scale capital dredging program at Onslow, northwestern Australia, were quantified to assess their effects on filter feeder communities, in particular sponges and suggest environmental filtering or passive adaptation acquired pre-dredging may have benefited these communities.
17 citations