Analyses of native water, bottom material, elutriate samples, and dredged material from selected southern Louisiana waterways and selected areas in the Gulf of Mexico, 1979-81

USGS Publications Warehouse

Lurry, Dee L.

1983-01-01

The U.S. Geological Survey was requested by the U.S. Army Corps of Engineers, New Orleans District, to provide water-quality data to evaluate environmental effects of dredging activities in selected reaches of the Calcasieu River in southwestern Louisiana. Samples were collected from the upper and lower Calcasieu River between January 1980 and March 1981. Thirty-three samples (22 native-water and 11 effluent) were collected from eleven dredging sites. In addition, a series of elutriate studies were conducted between July 1979 and July 1981 to determine water quality as a basis for assessing possible environmental effects of proposed dredging activities in the following areas: Grand Bayou and Martins Canal near Happy Jack, unnamed bayou near Port Sulphur, Grand Bayou and Pipeline Canal near Port Sulphur and Bayou des Plantins near Empire; Mississippi River Gulf Outlet and Inner Harbor Navigation Canal; Southwest Pass; Barataria Bay; Atchafalaya Bay at Eugene Island; Calcasieu Ship Channel. Samples of native water and samples of bottom material were collected from 22 different sites and elutriate (mixtures of native water and bottom material) samples were prepared and analyzed. Four proposed ocean-disposal sites were sampled for bottom material only. Samples were analyzed for selected chemical and biological constituents and physical properties. (USGS)

Site Management and Monitoring Plan (SMMP) for the Mouth of Columbia River- Deep and Shallow Water Ocean Dredged Material Disposal Sites, OR/WA

EPA Pesticide Factsheets

This SMMP is intended to provide management and monitoring strategies for disposal in the Mouth of Columbia River- Deep and Shallow Ocean Dredged Material Disposal Sites on the border of Oregon and Washington.

Beneficial Use of Dredged Material

EPA Pesticide Factsheets

An important goal of managing dredged material is to ensure that the material is used or disposed of in an environmentally sound manner.Most of this dredged material could be used in a beneficial manner instead.

Basalts dredged from the Amirante ridge, western Indian ocean

USGS Publications Warehouse

Fisher, R.L.; Engel, C.G.; Hilde, T.W.C.

1968-01-01

Oceanic tholeiitic basalts were dredged from 2500 to 3000 m depth on each flank of the Amirante Ridge, 1200 km southeast of Somalia in the western Indian Ocean, by R.V. Argo in 1964. One sample, probably shed from a flow or dike in basement beneath the coralline cap, gave a wholerock KAr age of 82??16??106 years. The age is similar to those reported by others for agglomerate from Providence Reef, nearer Madagascar, and for gabbro from Chain Ridge, the southwest member of Owen Fracture Zone, nearer the Somali coast. The Amirante Cretaceous-Early Tertiary occurrence lies between the "continental" 650 ?? 106 years granites of Seychelles Archipelago and the large Precambrian "continental" block of Madagascar. Trends of major structures and distribution of the related topographic and magnetic-anomaly lineations in 7-8 ?? 106 km2of the surrounding Indian Ocean suggest that in addition to spreading of the seafloor from the seismically-active Mid-Indian Ocean Ridge-Carlsberg Ridge complex there has been, since mid-Mesozoic time, distributed left-lateral shear along 52??-54??E that has moved Madagascar at least 700 km south relative to Seychelles Bank. Measurements by other indicate the absolute movement of Madagascar has been southward as well. The emplacement of oceanic tholeiitic basalts at shallow depth, the development of volcanic topography between the sedimented Somali and Mascarene basins, and the existence of the faulted Amirante Trench and Ridge are consequences of the displacement. ?? 1968.

75 FR 22524 - Ocean Dumping; Designation of Ocean Dredged Material Disposal Sites Offshore of the Siuslaw River...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-29

... location to dispose of material dredged from the Siuslaw River navigation channel, and to provide a... sediments from Site A back into the dredged channel resulted in a selection of disposal Sites B and C by the... conflicts. The final Sites are located close to the approach to the Siuslaw River entrance channel but are...

The effects of trawling, dredging and ocean dumping on the eastern Canadian continental shelf seabed

NASA Astrophysics Data System (ADS)

Messieh, S. N.; Rowell, T. W.; Peer, D. L.; Cranford, P. J.

1991-08-01

This paper presents an overview of current knowledge on the effects of trawling, dredging and ocean dumping on the eastern Canadian continental shelf seabed. The impact of trawling and dredging for fish and shellfish on marine habitats has recently attracted international attention among fisheries and environmental scientists. In Atlantic Canada, trawling and dredging are the principal methods of harvesting groundfish and scallops and ocean clams, respectively. It is estimated that fish trawlers and scallop dredges have swept tracks, cris-crossing the Canadian continental shelf, approximately 4.3 million km in length in 1985. In the past few years several studies were carried out by scientists from Canada, the United States and Europe to assess the impacts of trawling and dredging but results were inconclusive. Some studies showed physical damage as well as biological effects, whereas others indicated that the adverse effects were not considered to be serious. Fishermen are not the only potential users of the resources of the continental shelf. There is an increasing demand for good-quality sand and gravel aggregate and the ocean seabed is being seen as a possible source. The eastern Canadian continental shelf also exhibits hydrocarbon potential and operational and accidental discharges are an environmental concern. Increased marine transportation and expansion of the fishing fleet have resulted in a greater need for harbour dredging. Dredging and dredge spoil disposal were controlled by the Ocean Dumping Control Act and now the Canadian Environmental Protection Act which places restrictions on the composition of material that can be disposed of in the sea. Nevertheless some harbours contain contaminant concentrations exceeding the maximum allowable limits. It is concluded that the impacts of human activities on the continental shelf seabed environment are inevitable and the long-term effects, while difficult to determine, must be assessed. The sub-lethal effects

78 FR 73097 - Ocean Dumping; Sabine-Neches Waterway (SNWW) Ocean Dredged Material Disposal Site Designation

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-05

... of the Entrance Channel into the Gulf of Mexico, pursuant to the Marine Protection, Research and... exists, and if analysis of the dredged material indicates that it is suitable for open-water disposal... material from the Sabine-Neches Waterway, under the Marine Protection Research and Sanctuaries Act, 33 U.S...

Short and long-term effects of hydraulic dredging on benthic communities and ocean quahog (Arctica islandica) populations.

PubMed

Ragnarsson, Stefán Áki; Thorarinsdóttir, Gudrún G; Gunnarsson, Karl

2015-08-01

The short and long-term effects of hydraulic dredging on ocean quahog (Arctica islandica) populations and on non-target organisms were examined in Þistilfjörður Bay, NE Iceland over a five-year period. The overall species richness was low and the fauna was composed of species typical of sandy seabeds characterised by frequent wave-induced disturbances. The initial effects of dredging on the overall benthic community were large. Most taxa were significantly affected by dredging, with abundances sometimes decreasing or increasing by more than 50% immediately after dredging. However, with the exception of the ocean quahog, their recovery was rapid, and most taxa attained similar abundances as in the undisturbed control sediments after three months, and all did so after about a year. The effects of dredging on ocean quahogs were drastic and long-lasting. Of the original ocean quahog biomass before fishing took place, the dredge captured 82%, while a further 11% was lost as a result of mortality due to shell damage and predation. The total direct and indirect loss of ocean quahog biomass within dredged tracks due to fishing was thus 93%. The recovery of ocean quahogs in fished areas was extremely slow. Five years after dredging, the total ocean quahog biomass in tracks had increased from 7% to 26% relative to that in the controls. The proportional increase among ocean quahogs of targeted sizes (>70 mm) was from 2% to 14% over the same period. This study shows that while the longer-term effects of hydraulic dredging on non-target benthic organisms were small, the effects of dredging on ocean quahog densities were drastic, with full recovery expected to take place on decadal time-scales. The impacts of dredging on ocean quahog populations at the scale of the fishery are discussed. Copyright © 2015. Published by Elsevier Ltd.

Dredged Material Management in Long Island Sound

EPA Pesticide Factsheets

Information on Western and Central Long Island Sound Dredged Material Disposal Sites including the Dredged Material Management Plan and Regional Dredging Team. Information regarding the Eastern Long Island Sound Selected Site including public meetings.

Southeast Regional Implementation Manual for Requirements and Procedures for Evaluation of the Ocean Disposal of Dredged Material in Southeastern U.S. Atlantic and Gulf Coast Waters

EPA Pesticide Factsheets

This Regional Implementation Manual was prepared by EPA Region 4 to provide guidance for applicants proposing open-water disposal of dredged material in southeastern U.S. coastal waters of the Atlantic Ocean and the Gulf of Mexico.

Evaluation of Dredged Material Proposed for Ocean Disposal. Testing Manual

DTIC Science & Technology

1991-02-01

should include a deposit-feeding amphipod and a polychaete. Bioaccumulation tests generally should include a deposit-feeding bivalve mollusc and a...Gibson. 1987. Regulatory identification of petroleum hydrocarbons in dredged material. Proceedings of a Workshop. Misc. Pap. D-87-3, U.S. Army... Bioaccumulation from Whole-Sediment Tests. Polychaetes Molluscs Neanthes sp.* Macoma clam, Macoma sp.* Nereis sp.* Yoldia clam, Yoldia limatula Nephiy sp.* Nucula

15 CFR Appendix C to Subpart M of... - Dredged Material Disposal Sites Within the Sanctuary

Code of Federal Regulations, 2014 CFR

2014-01-01

... Commerce and Foreign Trade (Continued) NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE OCEAN AND COASTAL RESOURCE MANAGEMENT NATIONAL MARINE SANCTUARY PROGRAM REGULATIONS Monterey Bay National Marine Sanctuary Pt. 922, Subpt. M, App. C Appendix C to Subpart M of Part 922—Dredged Material...

40 CFR 227.13 - Dredged materials.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) Dredged material is composed predominantly of sand, gravel, rock, or any other naturally occurring bottom...) Dredged material is for beach nourishment or restoration and is composed predominantly of sand, gravel or... major constituents of the liquid phase are in compliance with the applicable marine water quality...

33 CFR 336.2 - Transportation of dredged material for the purpose of disposal into ocean waters.

Code of Federal Regulations, 2011 CFR

2011-07-01

... CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE FACTORS TO BE CONSIDERED IN THE EVALUATION OF ARMY CORPS OF ENGINEERS DREDGING PROJECTS INVOLVING THE DISCHARGE OF DREDGED MATERIAL INTO... Engineers may issue permits, after notice and opportunity for public hearing, for the transportation of...

78 FR 38672 - Ocean Dumping; Sabine-Neches Waterway (SNWW) Ocean Dredged Material Disposal Site Designation

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-27

... March 2011 prepared by the U.S. Army Corps of Engineers (also Corps or USACE). Appendix B of Volume III... be considered on the proposed site designations. The U.S. Army Corps of Engineers Final EIS for the... of dredged material from the Sabine-Neches Waterway. Currently, the US Army Corps of Engineers will...

Guidance on managing dredged material contaminated with dioxins and furans

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chase, T.; Dillon, T.

Approximately 400 million cubic yards of sediment are dredged from US navigation channels every year. While the vast majority of the dredged material are clean and thereby suitable for aquatic disposal, a portion of the dredged material are contaminated with chemicals that may pose risks to human health and the ecological health of the aquatic environment. Contaminated dredged materials are most frequently found downstream of industrial and municipal sewage-treatment discharges; non-point sources of pollution (e.g., urban and agricultural runoff) also contribute to contamination of dredged materials. An increasing amount of dredged materials are being identified through more sophisticated testing regimesmore » to pose potentially adverse risks to human health and the aquatic environment. One particular class of chemicals that raises concern when regulating dredged material disposal is dioxin, which has been found in sediment in a number of locations, including New Jersey/New York Harbor. Further testing will likely find that dredged materials are contaminated with low levels of dioxin across the country. Decision makers in the EPA and the USACE are guided by numerous statutory mandates and regulations. Within that framework, judgments about the suitability of dredged material for aquatic disposal are made based upon a tiered testing and evaluative process. Recently, the EPA and the USACE have been working to incorporate risk-based evaluation procedures into the dredged material decision-making process. This paper discusses such efforts to date and the preliminary recommendations for evaluating the potential effects of dioxin contaminated dredged material.« less

Beneficial use of dredged material for habitat creation, enhancement, and restoration in New York-New Jersey Harbor.

PubMed

Yozzo, David J; Wilber, Pace; Will, Robert J

2004-10-01

A comprehensive Dredged Material Management Plan (DMMP) has been developed by the US Army Corps of Engineers, New York District (USACE-NYD) and the Port Authority of New York and New Jersey (PANY/NJ). The primary objective of the DMMP is to identify cost-effective and environmentally acceptable alternatives for the placement of dredged material derived from ongoing and proposed navigation improvements within the PANY/NJ. A significant portion of this dredged material is classified as unsuitable for open-ocean disposal. One suite of alternatives presented within the DMMP is the beneficial use of dredged material for habitat creation, enhancement, and restoration within the NY/NJ Harbor Estuary. Proposed beneficial use/habitat development projects include the use of dredged material for construction of artificial reefs, oyster reef restoration, intertidal wetland and mudflat creation, bathymetric recontouring, filling dead-end canals/basins, creation of bird/wildlife islands, and landfill/brownfields reclamation. Preliminary screening of the proposed beneficial use alternatives identified advantages, disadvantages, potential volumes, and estimated costs associated with each project type. Continued study of the proposed beneficial use alternatives has identified areas of environmental research or technology development where further investigation is warranted.

DECONTAMINATION AND BENEFICIAL USE OF DREDGED MATERIALS.

DOE Office of Scientific and Technical Information (OSTI.GOV)

STERN, E.A.; LODGE, J.; JONES, K.W.

2000-12-03

Our group is leading a large-sale demonstration of dredged material decontamination technologies for the New York/New Jersey Harbor. The goal of the project is to assemble a complete system for economic transformation of contaminated dredged material into an environmentally-benign material used in the manufacture of a variety of beneficial use products. This requires the integration of scientific, engineering, business, and policy issues on matters that include basic knowledge of sediment properties, contaminant distribution visualization, sediment toxicity, dredging and dewatering techniques, decontamination technologies, and product manufacturing technologies and marketing. A summary of the present status of the system demonstrations including themore » use of both existing and new manufacturing facilities is given here. These decontamination systems should serve as a model for use in dredged material management plans of regions other than NY/NJ Harbor, such as Long Island Sound, where new approaches to the handling of contaminated sediments are desirable.« less

77 FR 63312 - Notice of Intent: Designation of an Ocean Dredged Material Disposal Site (ODMDS) in Eastern Long...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-16

... ENVIRONMENTAL PROTECTION AGENCY [FRL-9741-9] Notice of Intent: Designation of an Ocean Dredged...: Environmental Protection Agency (EPA). ACTION: Notice of Intent to prepare a Supplemental Environmental Impact...: EPA is authorized to designate ODMDS under section 102(c) of the Marine Protection, Research and...

77 FR 77076 - Notice of Intent: Designation of an Expanded Ocean Dredged Material Disposal Site (ODMDS) off...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-31

... area includes an area approximately 7.18 square miles in size, for the disposal of dredged material from the proposed harbor deepening dredging at Charleston Harbor (4.04 square miles are within the current ODMDS and 3.14 square miles are outside the current ODMDS). The size of an expanded ODMDS will...

Lake-dredged materials for beef cattle pasture establishment in subtropics

USDA-ARS?s Scientific Manuscript database

The ability to reuse dredge materials for agricultural purposes is important because it reduces offshore disposal and provides an alternative to disposal of the materials in landfills that are already overtaxed. Beneficial uses of dredging or dredged materials are both economical and environmental. ...

ECOLOGICAL EVALUATION OF PROPOSED DISCHARGE OF DREDGED MATERIAL INTO OCEAN WATERS; IMPLEMENTATION MANUAL FOR SECTION 103 OF PUBLIC LAW 92-532 (MARINE PROTECTION, RESEARCH, AND SANCTUARIES ACT OF 1972)

EPA Science Inventory

According to Section 103 of Public Law 92-532 (Marine Protection ,Research, and Sanctuaries Act of 1972), any proposed dumping of dredged material into ocean waters must be evaluated through the use of criteria published by the Environmental Protection Agency (EPA) i n the Federa...

Management of dredge material in the Republic of Ireland - A review.

PubMed

Sheehan, C; Harrington, J

2012-05-01

As an island nation the Republic of Ireland's ports and harbours are key to the economic wellbeing of the country as they are the primary transport link to the United Kingdom, mainland Europe and beyond. This paper examines the main aspects of the Irish dredging industry with comparison to international practice and standards, including the source of the dredge material and volumes generated annually, the dredging plant employed and the management processes currently practised. Relevant European and Irish legislation governing dredging, disposal at sea and waste licensing are presented. The potential impacts of disposal at sea are discussed with the implications for the Irish dredging industry of recently introduced European Directives assessed. Beneficial use rates for dredge material and the techniques implemented in Ireland are examined and compared with international practice. Recent notable beneficial use projects for dredge material and proposed innovative dredge material management techniques for specific dredging projects in Ireland are presented. Proposals to encourage greater beneficial use of dredge material and minimise disposal at sea for Ireland are presented including the introduction of environmental credits, tax breaks and a grant system for pilot schemes. An alternative disposal at sea charge fee structure is also recommended to encourage alternative dredge material management practices. Ireland's management of contaminated sediment is also presented with recent projects described highlighting the current practice of primarily exporting contaminated sediment to mainland Europe. Alternative methods of treatment of contaminated sediment are assessed in an Irish context. Future issues and challenges facing the Irish dredging industry are assessed and a critical analysis of the current approaches to dredge material management is presented. Copyright © 2011 Elsevier Ltd. All rights reserved.

Evaluation of dredged material proposed for ocean disposal from Hudson River, New York

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gardiner, W.W.; Barrows, E.S.; Antrim, L.D.

1996-09-01

The Hudson River (Federal Project No. 41) was one of seven waterways that the U.S. Army Corps of Engineers-New York District (USACE-NYD) requested the Battelle Marine Sciences Laboratory (MSL) to sample and evaluate for dredging and disposal in March 1994. Sediment samples were collected from the Hudson River. Tests and analyses were conducted on Hudson River sediment core samples. The evaluation of proposed dredged material from the Hudson River included bulk sediment chemical analyses, chemical analyses of site water and elutriate, water-column and benthic acute toxicity tests, and bioaccumulation studies. Individual sediment core samples collected from Hudson River were analyzedmore » for grain size, moisture content, and total organic carbon (TOC). A composite sediment sample, representing the entire area proposed for dredging, was analyzed for bulk density, specific gravity, metals, chlorinated pesticides, polychlorinated biphenyl (PCB) congeners, polynuclear aromatic hydrocarbons (PAH), and 1,4-dichlorobenzene. Site water and elutriate water, prepared from the suspended-particulate phase (SPP) of Hudson River sediment, were analyzed for metals, pesticides, and PCBS. Water-column or SPP toxicity tests were performed with three species. Benthic acute toxicity tests were performed. Bioaccumulation tests were also conducted.« less

Laboratory Assessment of Potential Impacts to Dungeness Crabs from Disposal of Dredged Material from the Columbia River

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vavrinec, John; Pearson, Walter H.; Kohn, Nancy P.

2007-05-07

Dredging of the Columbia River navigation channel has raised concerns about dredging-related impacts on Dungeness crabs (Cancer magister) in the estuary, mouth of the estuary, and nearshore ocean areas adjacent to the Columbia River. The Portland District, U.S. Army Corps of Engineers engaged the Marine Sciences Laboratory (MSL) of the U.S. Department of Energy’s Pacific Northwest National Laboratory to review the state of knowledge and conduct studies concerning impacts on Dungeness crabs resulting from disposal during the Columbia River Channel Improvement Project and annual maintenance dredging in the mouth of the Columbia River. The present study concerns potential effects onmore » Dungeness crabs from dredged material disposal specific to the mouth of the Columbia River.« less

15 CFR Appendix C to Subpart M of... - Dredged Material Disposal Sites Within the Sanctuary

Code of Federal Regulations, 2010 CFR

2010-01-01

... 15 Commerce and Foreign Trade 3 2010-01-01 2010-01-01 false Dredged Material Disposal Sites Within the Sanctuary C Appendix C to Subpart M of Part 922 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign Trade (Continued) NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF...

Managing Ocean Dumping in EPA Region 4

EPA Pesticide Factsheets

Overview of ocean dumping in Southeast United States. Includes materials dumped in the Region, ocean dumping permits issues, dredged material testing guidance, ocean disposal site descriptions and information, regional dredging teams and other partnerships

Managing Ocean Dumping in EPA Region 1

EPA Pesticide Factsheets

Overview of ocean dumping in New England, US. Includes materials dumped in the Region, ocean dumping permits issues, dredged material testing guidance, ocean disposal site descriptions and information, regional dredging teams and other partnerships.

Managing Ocean Dumping in EPA Region 6

EPA Pesticide Factsheets

Overview of ocean dumping in South Central, US. Includes materials dumped in the Region, ocean dumping permits issues, dredged material testing guidance, ocean disposal site descriptions and information, regional dredging teams and other partnerships

Managing Ocean Dumping in EPA Region 3

EPA Pesticide Factsheets

Overview of ocean dumping in Mid Atlantic, US. Includes materials dumped in the Region, ocean dumping permits issues, dredged material testing guidance, ocean disposal site descriptions and information, regional dredging teams and other partnerships.

Managing Ocean Dumping in EPA Region 10

EPA Pesticide Factsheets

Overview of ocean dumping in Pacific Northwest, US. Includes materials dumped in the Region, ocean dumping permits issues, dredged material testing guidance, ocean disposal site descriptions and information, regional dredging teams and other partnerships.

Managing Ocean Dumping in EPA Region 2

EPA Pesticide Factsheets

Overview of ocean dumping in NY, NJ and Puerto Rico. Includes materials dumped in the Region, ocean dumping permits issues, dredged material testing guidance, ocean disposal site descriptions and information, regional dredging teams and other partnerships

Towards the assessment and management of contaminated dredged materials.

PubMed

Agius, Suzanne J; Porebski, Linda

2008-04-01

Environment Canada's Disposal at Sea Programme hosted the Contaminated Dredged Material Management Decisions Workshop in Montreal, Quebec, Canada, on 28-30 November 2006. The workshop brought together over 50 sediment assessment and management experts from academic, industrial, and regulatory backgrounds and charged them with drafting a potential framework to assess contaminated dredged materials and compare the risks of various disposal alternatives. This article summarizes the recommendations made during the workshop concerning the development of sediment assessment tools, the interpretation of these tools, and the essential attributes of a comparative risk assessment process. The major outcomes of the workshop include a strong recommendation to develop a national dredging or sediment management strategy, a potential decision-making framework for the assessment of dredged materials and comparative risk assessment of disposal options, and the expansion of minimum sediment characterization requirements for nonroutine disposal permit applications.

Screening-level risk assessment applied to dredging of polluted sediments from Guanabara Bay, Rio de Janeiro, Brazil.

PubMed

Silveira, Ana Elisa F; Nascimento, Juliana R; Sabadini-Santos, Elisamara; Bidone, Edison D

2017-05-15

Guanabara Bay is characterized by predominant eutrophication and anoxic sediments with a mixture of pollutants. The risk prognosis associated with the dumping of its dredged sediments into the open ocean was addressed by our algorithm. Our algorithm could prioritize areas, characterize major processes related to dredging, measure the potential risk of sediments, and predict the effects of sediment mixing. The estimated risk of dredged sediment was >10-fold than that of ocean sediments. Among metals, mercury represented 50-90% of the total risk. The transfer of dredged material into the ocean or internal dumping in the bay requires a 1:10 dilution to mitigate the risk and bring the risk levels close to that in the EPA criteria, below which there is less likelihood of adverse effects to the biota, and a 1:100 dilution to maintain the original characteristics of the ocean disposal control area. Our algorithm indicator can be used in the design of both aquatic and continental disposal of dredged materials and their management. Copyright © 2017. Published by Elsevier Ltd.

DREDGED MATERIAL RECLAMATION AT THE JONES ISLAND CONFINED DISPOSAL FACILITY - ITER

EPA Science Inventory

In this SITE demonstration, phytoremediation technology was applied to contaminated dredged materials from the Jones Island Confined Disposal Facility (CDF) located in Milwaukee Harbor, Wisconsin. The Jones Island CDF receives dredged materials from normal maintenance of Milwauke...

Managing dredged material in the coastal zone of the Baltic Sea.

PubMed

Staniszewska, Marta; Boniecka, Helena

2017-01-01

This article deals with the legal and practical recommendations for the management of dredged material in the riparian countries of the Baltic Sea. The recommendations are contained in three conventions: LC, 2000. London Convention (1972), Convention on the Protection of the Marine Environment of the Baltic Sea area (Helsinki Convention) (1992), the OSPAR Convention (1972). Different approaches to evaluating the contamination level of dredge spoils, used by the Baltic Sea riparian countries, have been characterized. The differences in those approaches manifest themselves by various concentration limits for contaminants, which form a basis for the classification of dredged material as either contaminated or non-contaminated, and thus determine how the spoils will be processed further. Based on the collected information about the concentration limits for contaminants of surface sediments in the coastal ports, it was pointed out that it is necessary to conduct routine monitoring of heavy metals, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, tributyltin, and petroleum hydrocarbons in dredged sediments in all the Baltic Sea states. On the other hand, the monitoring of polychlorinated dibenzo-p-dioxins/furans, organochlorine, and organophosphoric pesticides is only needed in locations that are suspected of historical or being the local contamination sources. Due to significant economic limitations of chemical determinations, it is important to consider a simple screening test of sediment that would say whether sediment may be "contaminated" and qualifies for more detailed and costly chemical research. It may be typical basic physical-chemical analysis of sediments or ecotoxicological classification of sediments.Despite environmentally friendly tendencies, the practical application of dredged material within the Baltic Sea area is very limited. Dredged material is most frequently stored at the specifically designated sites. From among the practical uses of

TOXICITY TESTING, RISK ASSESSMENT, AND OPTIONS FOR DREDGED MATERIAL MANAGEMENT

EPA Science Inventory

Programs for evaluating proposed discharges of dredged material into waters of the United States specify a tiered testing and evaluation protocol that includes performance of acute and chronic bioassays to assess toxicity of the dredged sediments. Although these evaluations refl...

Stakeholder engagement in dredged material management decisions.

PubMed

Collier, Zachary A; Bates, Matthew E; Wood, Matthew D; Linkov, Igor

2014-10-15

Dredging and disposal issues often become controversial with local stakeholders because of their competing interests. These interests tend to manifest themselves in stakeholders holding onto entrenched positions, and deadlock can result without a methodology to move the stakeholder group past the status quo. However, these situations can be represented as multi-stakeholder, multi-criteria decision problems. In this paper, we describe a case study in which multi-criteria decision analysis was implemented in a multi-stakeholder setting in order to generate recommendations on dredged material placement for Long Island Sound's Dredged Material Management Plan. A working-group of representatives from various stakeholder organizations was formed and consulted to help prioritize sediment placement sites for each dredging center in the region by collaboratively building a multi-criteria decision model. The resulting model framed the problem as several alternatives, criteria, sub-criteria, and metrics relevant to stakeholder interests in the Long Island Sound region. An elicitation of values, represented as criteria weights, was then conducted. Results show that in general, stakeholders tended to agree that all criteria were at least somewhat important, and on average there was strong agreement on the order of preferences among the diverse groups of stakeholders. By developing the decision model iteratively with stakeholders as a group and soliciting their preferences, the process sought to increase stakeholder involvement at the front-end of the prioritization process and lead to increased knowledge and consensus regarding the importance of site-specific criteria. Published by Elsevier B.V.

DREDGED MATERIAL RECLAMATION AT THE JONES ISLAND CONFINED DISPOSAL FACILITY SITE CAPSULE

EPA Science Inventory

In this SITE demonstration, phytoremediation technology was applied to contaminated dredged materials from the Jones Island Confined Disposal Facility (CDF) located in Milwaukee Harbor, Wisconsin. The Jones Island CDF receives dredged materials from normal maintenance of Milwauke...

Two bathyal hydroids (Hydrozoa: Leptothecata) from the Southwest Indian Ocean.

PubMed

Watson, Jeanette E

2017-03-27

Two species of hydroids were recovered from a mooring rope and experimentally deployed whale bone attached to an underwater transponder buoy at a depth of 732 m on the Coral Seamount on the Southwest Indian Ocean Ridge (41° 22.31'S, 54° 57'E) in the Southern Indian Ocean. The material was collected approximately 1,500 km south south-east of Madagascar during Voyage JC066 of the British Royal Research Ship R.R.S. James Cook on 20/11/2011. Hydroids were collected from the mooring rope and whale bone on board the ship after underwater retrieval by ROV.

15 CFR Appendix D to Subpart M of... - Dredged Material Disposal Sites Adjacent to the Monterey Bay National Marine Sanctuary

Code of Federal Regulations, 2010 CFR

2010-01-01

... 15 Commerce and Foreign Trade 3 2010-01-01 2010-01-01 false Dredged Material Disposal Sites Adjacent to the Monterey Bay National Marine Sanctuary D Appendix D to Subpart M of Part 922 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign Trade (Continued) NATIONAL OCEANIC AND...

Landfill closure with dredged materials - desktop analysis.

DOT National Transportation Integrated Search

2014-08-01

This report describes a Rutgers University project for the New Jersey Department of : Transportation (NJDOT) designed to analyze the potential for closure of New Jersey : landfills using dredge material from existing Confined Disposal Facilities (CDF...

Chemical gradients in sediment cores from an EPA reference site off the Farallon Islands - Assessing chemical indicators of dredged material disposal in the deep sea

USGS Publications Warehouse

Bothner, Michael H.; Gill, P.W.; Boothman, W.S.; Taylor, B.B.; Karl, Herman A.

1998-01-01

Heavy metal and organic contaminants have been determined in undisturbed sediment cores from the US Environmental Protection Agency reference site for dredged material on the continental slope off San Francisco. As expected, the concentrations are significantly lower than toxic effects guidelines, but concentrations of PCBs, PAHs, Hg, Pb, and Clostridium perfringens (a bacterium spore found in sewage) were nearly two or more times greater in the surface sediments than in intervals deeper in the cores. These observations indicate the usefulness of measuring concentration gradients in sediments at the San Francisco deep ocean disposal site (SF-DODS) where a thin (0.5 cm thick) layer of dredged material has been observed beyond the boundary. This thin layer has not been chemically characterized by the common practice of homogenizing over the top 10 cm. An estimated 300 million cubic yards of dredged material from San Francisco Bay are expected to be discharged at the SF-DODS site during the next 50 years. Detailed depth analysis of sediment cores would add significant new information about the fate and effects of dredged material in the deep sea.

Recycled Glass and Dredged Materials

DTIC Science & Technology

2007-03-01

stations, and is either source-separated or co-mingled with plastics, aluminum cans, ceramics , or colored glass containers. In the United States in...anything other than container glass ). The debris may contain contaminants including ceramics (from dishware, pottery, window glass , light bulbs...ERDC TN-DOER-T8 March 2007 Recycled Glass and Dredged Materials by Landris T. Lee, Jr. PURPOSE: This technical note explores the concepts

Federal Standard: Beneficial Use of Dredged Material

EPA Pesticide Factsheets

The purpose of this document is to provide national guidance that explains the role of the Federal Standard in implementing beneficial uses of dredged material from U.S. Army Corps of Engineers’ new and maintenance navigation projects.

GREAT I Study of the Upper Mississippi River. Technical Appendixes. Volume 2. Floodplain Management, Dredged Material Uses, Dredging Requirements.

DTIC Science & Technology

1980-09-01

placement of dredged material is proposed, a quantitative analysis of the effects on the 1-percent chance flood be made. The analysis must include a...FPMWG will accept the site. b. Until a quantitative analysis is conducted, place- ment sites be selected following these guidelines. (1) Dredge4 material... Analysis of site-specific encroachments would continue to be made without considering the opposite bank impacts or the long-term cumulative effects. 5

Marine dredged sediments as new materials resource for road construction.

PubMed

Siham, Kamali; Fabrice, Bernard; Edine, Abriak Nor; Patrick, Degrugilliers

2008-01-01

Large volumes of sediments are dredged each year in Europe in order to maintain harbour activities. With the new European Union directives, harbour managers are encouraged to find environmentally sound solutions for these materials. This paper investigates the potential uses of Dunkirk marine dredged sediment as a new material resource for road building. The mineralogical composition of sediments is evaluated using X-ray diffraction and microscopy analysis. Since sediments contain a high amount of water, a dewatering treatment has been used. Different suitable mixtures, checking specific geotechnical criteria as required in French standards, are identified. The mixtures are then optimized for an economical reuse. The mechanical tests conducted on these mixtures are compaction, bearing capacity, compression and tensile tests. The experimental results show the feasibility of the beneficial use of Dunkirk marine dredged sand and sediments as a new material for the construction of foundation and base layers for roads. Further research is now needed to prove the resistance of this new material to various environmental impacts (e.g., frost damage).

Spice: Southwest Pacific Ocean Circulation and Climate Experiment

NASA Astrophysics Data System (ADS)

Ganachaud, A. S.; Melet, A.; Maes, C.

2010-12-01

South Pacific oceanic waters are carried from the subtropical gyre centre in the westward flowing South Equatorial Current (SEC), towards the southwest Pacific-a major circulation pathway that redistributes water from the subtropics to the equator and Southern Ocean. The transit in the Coral Sea is potentially of great importance to tropical climate prediction because changes in either the temperature or the amount of water arriving at the equator have the capability to modulate ENSO and produce basin-scale climate feedbacks. The south branch is associated with comparable impacts in the Tasman Sea area. The Southwest Pacific is a region of complex circulation, with the SEC splitting in strong zonal jets upon encountering island archipelagos. Those jets partition on the Australian eastern boundary to feed the East Australian Current for the southern branch and the North Queensland Current and eventually the Equatorial Undercurrent for the northern branch. On average, the oceanic circulation is driven by the Trade Winds, and subject to substantial variability, related with the South Pacific Convergence Zone (SPCZ) position and intensity. The circulation, and its influence on remote and regional climate, is poorly understood due to the lack of appropriate measurements. Ocean and atmosphere scientists from Australia, France, New Zealand, the United States and Pacific Island countries initiated an international research project under the auspices of CLIVAR to comprehend the southwest Pacific Ocean circulation and its direct and indirect influence on the climate and environment. SPICE is a regionally-coordinated experiment to measure, study and monitor the ocean circulation and the SPCZ, to validate and improve numerical models, and to integrate with assimilating systems. This ongoing project reflects a strong sense that substantial progress can be made through collaboration among South Pacific national research groups, coordinated with broader South Pacific projects.

Humboldt Open Ocean Disposal Site (HOODS) Survey Work 2014

EPA Pesticide Factsheets

The Humboldt Open Ocean Disposal Site (HOODS) is a dredged material disposal site located 3 nautical miles (nm) offshore of Humboldt Bay in Northern California. HOODS was permanently designated by EPA Region 9 in 1995, and has been actively used for dredged material disposal operations since then. The HOODS has received higher volumes of dredged material than predicted since its designation in 1995, mainly from USACE construction and maintenance dredging.

Impacts of maintenance dredged material disposal on macrobenthic structure and secondary productivity.

PubMed

Bolam, S G; Barry, J; Bolam, T; Mason, C; Rumney, H S; Thain, J E; Law, R J

2011-10-01

The results of a monitoring programme to assess the spatial impacts associated with ongoing dredged material disposal activity at a dispersive, coastal disposal site (southwest UK) are described. Benthic impacts were assessed using benthic community structure and secondary productivity estimates. Analyses of univariate indices (including secondary production) and multivariate community structure revealed differences between stations inside and those outside the disposal site were minimal. Generally, stations within and outside the disposal site were characterised by the same species. Regression models indicated that the variability in biological structure and secondary production was predominantly accounted for by natural variables (e.g., depth, sediment granulometry) with only a small amount of residual variability being due to contaminant variables. Thus, the elevated levels of certain contaminants in the vicinity of the disposal area were not sufficient to result in significant ecological or ecotoxicological changes. We ascribe such findings partly to the dispersive nature of the disposal site. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

Dredged Material Analysis Tools; Performance of Acute and Chronic Sediment Toxicity Methods

DTIC Science & Technology

2008-04-01

Chronic Sediment Toxicity Methods Jeffery Steevens, Alan Kennedy, Daniel Farrar, Cory McNemar, Mark R. Reiss, Roy K. Kropp, Jon Doi, and Todd Bridges...Research Program ERDC/EL TR-08-16 April 2008 Dredged Material Analysis Tools Performance of Acute and Chronic Sediment Toxicity Methods Jeffery...potential advan- tages and disadvantages of using chronic sediment toxicity tests with relevant benthic macroinvertebrates as part of dredged material

Aspects of oceanic forcing of drought over Southwest Asia and the United States

NASA Astrophysics Data System (ADS)

Hoell, Andrew

An exceptionally severe drought affected much of the Northern Hemisphere mid-latitudes during 1998 -- 2002, with maxima over Southwest Asia and the United States. Previous research has suggested that the oceans played an important role in the hemispheric drought, with oceanic links to tropical Indo-west Pacific Ocean convection highlighted as important for Southwest Asia, and several additional ocean regions suggested as important for the United States. Here, the regional and hemispheric circulation response to tropical Indo-west Pacific Ocean convection is examined for both Southwest Asia and the United States, and the relative importance of individual sea surface temperature areas are explored for United States precipitation. For Southwest Asia, the regional thermodynamic forcing of precipitation and the Northern Hemisphere circulation are related to the leading pattern of Indian Ocean precipitation and its intraseasonal and interannual contributions. Both intraseasonal and interannual timescales are associated with baroclinic Gill-Matsuno-like circulation responses extending over southern Asia, but the interannual component also has a strong equivalent-barotropic circulation. A stationary barotropic Rossby wave extending over North America is associated with interannual tropical Indo-west Pacific Ocean convection and is supported by barotropic ray tracing. For United States regions, historical SST and precipitation links are identified for 1948 -- 1997, and the importance of these links are assessed during the 1998 -- 2002 drought using a linear regression model. The reconstructed precipitation has good correspondence for the Southwest and Southeast United States, but is not able to reproduce precipitation variability over the Northwest and Central United States, especially Texas.

A regional ocean model for the Southwest Pacific Ocean region to assess the risk of storms

NASA Astrophysics Data System (ADS)

Natoo, N.; Paul, A.; Hadfield, M.; Jendersie, S.; Bornman, J.; de Lange, W.; Ye, W.; Schulz, M.

2012-04-01

New Zealand's coasts are not only affected by mid-latitude storms, but infrequently also by storms that originate from the tropics. Projections for the southern hemisphere's southwest Pacific island countries for the 21st century show a poleward shift of the mid-latitude storm tracks, which consequently might result in changes in wind, precipitation and temperature patterns. Furthermore, an increase in frequency of intense storms is expected for the New Zealand region, which will very likely increase the risk of storm surges and flooding of coastal and low-lying regions. We employ the Regional Ocean Modeling System (ROMS) to assess the changes in the storm climate of the New Zealand region. The model set-up uses a resolution of ~50 km for the Southwest Pacific Ocean "parent domain" and ~10 km for the New Zealand "child domain", to well represent the major eddies that influence the climate of North Island. With the aim to later utilize this nested ocean model set-up as part of a coupled ocean-atmosphere modelling system for the Southwest Pacific Ocean region, results for the 20th century will be presented. The simulated circulation is shown to be largely consistent with the observed regional oceanography.

Dredging Operations Technical Support Program. Design and Management of Dredged Material Containment Areas to Improve Hydraulic Performance.

DTIC Science & Technology

1987-06-01

in chlorine contact chambers were not sensit ive to experimentil procedure, and ’"When the dye test was repeated on the same hsin undcr ident i ; I I...neither YA t 1idth nor Ienzth ar’ 1n t -r,1ined i u , nd i t ion, costs are , iunti , t ion I .< and N . ( u yen % and Iltl ;I<,, r[i,. hte used tc com...DREDGING OPERATIONS TECHNICAL SUPPORT PROGRAM TEHIA REPORT D-87-2 DESIGN AND MANAGEMENT OF DREDGED MATERIAL CONTAINMENT AREAS TO% N IMPROVE

New Experiences in Dike Construction with Soil-Ash Composites and Fine-Grained Dredged Materials

NASA Astrophysics Data System (ADS)

Duszyński, Remigiusz; Duszyńska, Angelika; Cantré, Stefan

2017-12-01

The supporting structure inside a coastal dike is often made of dredged non-uniform sand with good compaction properties. Due to the shortage of natural construction material for both coastal and river dikes and the surplus of different processed materials, new experiments were made with sand-ash mixtures and fine-grained dredged materials to replace both dike core and dike cover materials resulting in economical, environmentally friendly and sustainable dikes. Ash from EC Gdańsk and dredged sand from the Vistula river were mixed to form an engineering material used for dike construction. The optimum sand-ash composites were applied at a field test site to build a large-scale research dike. Fine-grained dredged materials from Germany were chosen to be applied in a second full-scale research dike in Rostock. All materials were investigated according to the standards for soil mechanical analysis. This includes basic soil properties, mechanical characteristics, such as grain-size distribution, compaction parameters, compressibility, shear strength, and water permeability. In the field, the infiltration of water into the dike body as well as the erosion resistance of the cover material against overflowing water was determined. Results of both laboratory and field testing are discussed in this paper. In conclusion, the mixing of bottom ash with mineral soil, such as relatively uniform dredged sand, fairly improves the geotechnical parameters of the composite, compared to the constituents. Depending on the composite, the materials may be suitable to build a dike core or an erosion-resistant dike cover.

Valorization of unauthorized sea disposal dredged sediments as a road foundation material.

PubMed

Achour, Raouf; Abriak, Nor-Edine; Zentar, Rachid; Rivard, Patrice; Gregoire, Pascal

2014-08-01

The main objective of this study is to show the ability of fine dredged material (mainly silty material) to be used in road construction project. This paper is divided into three parts. In the first part, the physical, the mineralogical and the mechanical characteristics of the used fine dredged sediments, as well as their chemical composition and environmental impacts are presented. In the second part, the methodology developed to design the road made from dredged fine sediment is developed. The third part of the paper focuses on the presentation of the road construction and the interpretation of analyses made on cores drilled samples from the road and measurements of the deflection of the road. The environmental assessment, based on leaching tests, is also performed at different issues.

Magma Supply of Southwest Indian Ocean: Implication from Crustal Thickness Anomalies

NASA Astrophysics Data System (ADS)

Chiheng, L.; Jianghai, L.; Huatian, Z.; Qingkai, F.

2017-12-01

The Southwest Indian Ridge (SWIR) is one of the world's slowest spreading ridges with a full spreading rate of 14mm a-1, belonging to ultraslow spreading ridge, which are a novel class of spreading centers symbolized by non-uniform magma supply and crustal accretion. Therefore, the crustal thickness of Southwest Indian Ocean is a way to explore the magmatic and tectonic process of SWIR and the hotspots around it. Our paper uses Residual Mantle Bouguer Anomaly processed with the latest global public data to invert the relative crustal thickness and correct it according to seismic achievements. Gravity-derived crustal thickness model reveals a huge range of crustal thickness in Southwest Indian Ocean from 0.04km to 24km, 7.5km of average crustal thickness, and 3.5km of standard deviation. In addition, statistics data of crustal thickness reveal the frequency has a bimodal mixed skewed distribution, which indicates the crustal accretion by ridge and ridge-plume interaction. Base on the crustal thickness model, we divide three types of crustal thickness in Southwest Indian Ocean. About 20.31% of oceanic crust is <4.8km thick designated as thin crust, and 60.99% is 4.8-9.8km thick as normal crust. The remaining 18.70% is >9.8km thick as thick crust. Furthermore, Prominent thin crust anomalies are associated with the trend of most transform faults, but thick crust anomalies presents to northeast of Andrew Bain transform fault. Cold and depleted mantle are also the key factors to form the thin crust. The thick crust anomalies are constrained by hotspots, which provide abundant heat to the mantle beneath mid-ocean ridge or ocean basin. Finally, we roughly delineate the range of ridge-plume interaction and transform fault effect.

U.S. Navy Harbor Maintenance Dredging Atlas.

DTIC Science & Technology

1980-12-01

the ocean’s surf zone. Energy is so high that mud size (clay and silt) sediments are washed away leaving deposits of sand. Sand is rarely contaminated...Figure 11). Dredging is contracted for by the Atlantic Division, Naval Facilities Engineering Command (LANTNAVFACENGCOM). The hydraulically dredged spoil...by the Atlantic Ocean to the east and the St. Johns River on the north. The Mayport Naval Station is a major base, homeporting over 30 ships including

77 FR 23668 - Intent To Prepare a Draft Environmental Impact Statement for a 20-Year Dredged Material...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-20

... Environmental Impact Statement for a 20-Year Dredged Material Management Plan for the Atlantic Intracoastal... Engineers is the lead Federal agency for an evaluation of the maintenance dredging of the Atlantic... analyze the impacts of the maintenance dredging of this portion of the AIWW, including disposal of dredged...

Multi-platform assessment of turbidity plumes during dredging operations in a major estuarine system

NASA Astrophysics Data System (ADS)

Caballero, Isabel; Navarro, Gabriel; Ruiz, Javier

2018-06-01

Dredging activities in estuaries frequently cause deleterious environmental effects on the water quality which can impact flora, fauna, and hydrodynamics, among others. A medium- and high-resolution satellite-based procedure is used in this study to monitor turbidity plumes generated during the dredging operations in the Guadalquivir estuary, a major estuarine system providing important ecosystem services in southwest Europe. A multi-sensor scheme is evaluated using a combination of five public and commercial medium- and high-resolution satellites, including Landsat-8, Sentinel-2A, WorldView-2, WorldView-3, and GeoEye-1, with pixel sizes ranging from 30 m to 0.3 m. Applying a multi-conditional algorithm after the atmospheric correction of the optical imagery with ACOLITE, Sen2Cor and QUAC processors, it is demonstrated the feasibility to monitoring suspended solids during dredging operations at a spatial resolution unachievable with traditional satellite-based ocean color sensors (>300 m). The frame work can be used to map on-going, post and pre-dredging activities and asses Total Suspended Solids (TSS) anomalies caused by natural and anthropogenic processes in coastal and inland waters. These promising results are suitable to effectively improve the assessment of features relevant to environmental policies for the challenging coastal management and might serve as a notable contribution to the Earth Observation Program.

Guidelines for Selecting Control and Treatment Options for Contaminated Dredged Material.

DTIC Science & Technology

1986-09-01

application of the DMASS to selection of control/treatment alternatives. The Totem Ocean Trailer Express Terminal Project in the Blair Waterway was...resuspension to a minimum. Limitations may be placed on levels of suspended solids when even normal dredging operations occur around public areas or coral ... reefs or during certain periods in the life cycle of a specific marine species (Lunz, Clark, and Fredette 1984). However, the major problems from

Petrography and U-Pb detrital zircon geochronology of metasedimentary strata dredged from the Chukchi Borderland, Amerasia Basin, Arctic Ocean

NASA Astrophysics Data System (ADS)

Brumley, K.; Miller, E. L.; Mayer, L. A.; Andronikov, A.; Wooden, J. L.; Dumitru, T. A.; Elliott, B.; Gehrels, G. E.; Mukasa, S. B.

2010-12-01

In 2008-2009, twelve dredges were taken aboard the USCGC Healy from outcrops along the Alpha Ridge, Northern Chukchi Borderland, Northwind Ridge and the Chukchi Plateau in the Arctic Ocean as part of the U.S. Extended Continental Shelf Project. To ensure sampling of outcrop, steep bathymetric slopes (>40°) with little mud cover were identified with multibeam sonar and targeted for dredging. The first dredge from Alpha Ridge yielded volcaniclastic sedimentary rocks deposited from a phreatomagmatic eruption in shallow water (<200m). This is inconsistent with tectonic reconstructions suggesting that the Alpha Ridge was created as an oceanic plateau on deep oceanic crust of the Canada Basin. Another dredge, taken from the northern tip of Northwind Ridge, yielded metasedimentary rocks deformed under greenschist facies conditions (chlorite+white mica). These rocks are intruded and/or overlain by mid-Cretaceous alkalic basalts, also taken in this dredge, and dated by 40Ar/39Ar (plagioclase separate) to be 112±1 Ma. The metasedimentary rocks, from this single dredge, range in grain size from mud to coarse sandstone and grit which all contain grains and sub-angular clasts of volcanic, plutonic, metamorphic and fine grained sedimentary rocks as well as monocrystalline quartz, potassium feldspar, and plagioclase. All of these samples display the same bedding to foliation angle and lithology, which further indicates that they were dredged from in situ outcrop and are not random samples of ice rafted debris. Based on grain size variations and graded beds, they are interpreted as Silurian gravity flow deposits fed by proximal syn-orogenic and/or magmatic arc sources. Detrital zircons were separated from four sandstone samples of the Northwind Ridge dredge, and their U-Pb single grain ages determined by LA-MC-ICPMS and SHRIMP, (N= 393). Their detrital zircon populations are dominated by euhedral first-cycle zircon ca. 430 and 980 Ma with lesser older recycled zircons between

The Southwest Pacific Ocean circulation and climate experiment (SPICE)

NASA Astrophysics Data System (ADS)

Ganachaud, A.; Cravatte, S.; Melet, A.; Schiller, A.; Holbrook, N. J.; Sloyan, B. M.; Widlansky, M. J.; Bowen, M.; Verron, J.; Wiles, P.; Ridgway, K.; Sutton, P.; Sprintall, J.; Steinberg, C.; Brassington, G.; Cai, W.; Davis, R.; Gasparin, F.; Gourdeau, L.; Hasegawa, T.; Kessler, W.; Maes, C.; Takahashi, K.; Richards, K. J.; Send, U.

2014-11-01

The Southwest Pacific Ocean Circulation and Climate Experiment (SPICE) is an international research program under the auspices of CLIVAR. The key objectives are to understand the Southwest Pacific Ocean circulation and the South Pacific Convergence Zone (SPCZ) dynamics, as well as their influence on regional and basin-scale climate patterns. South Pacific thermocline waters are transported in the westward flowing South Equatorial Current (SEC) toward Australia and Papua-New Guinea. On its way, the SEC encounters the numerous islands and straits of the Southwest Pacific and forms boundary currents and jets that eventually redistribute water to the equator and high latitudes. The transit in the Coral, Solomon, and Tasman Seas is of great importance to the climate system because changes in either the temperature or the amount of water arriving at the equator have the capability to modulate the El Niño-Southern Oscillation, while the southward transports influence the climate and biodiversity in the Tasman Sea. After 7 years of substantial in situ oceanic observational and modeling efforts, our understanding of the region has much improved. We have a refined description of the SPCZ behavior, boundary currents, pathways, and water mass transformation, including the previously undocumented Solomon Sea. The transports are large and vary substantially in a counter-intuitive way, with asymmetries and gating effects that depend on time scales. This paper provides a review of recent advancements and discusses our current knowledge gaps and important emerging research directions.

Biosolids and dredged materials: alternative sources of nutrients for crop productivity and sustainability of pasture-based agroecosystem

USDA-ARS?s Scientific Manuscript database

Domestic sewage sludge or “biosolids” and lake-dredged materials are examples of materials that can be used to cut fertilizer costs in pasture-based animal agriculture. Sustainable biosolids and lake-dredged materials management is based upon controlling and influencing the quantity, quality and cha...

15 CFR Appendix C to Subpart M of... - Dredged Material Disposal Sites Within the Sanctuary

Code of Federal Regulations, 2011 CFR

2011-01-01

... 15 Commerce and Foreign Trade 3 2011-01-01 2011-01-01 false Dredged Material Disposal Sites Within the Sanctuary C Appendix C to Subpart M of Part 922 Commerce and Foreign Trade Regulations Relating to... National Marine Sanctuary Pt. 922, Subpt. M, App. C Appendix C to Subpart M of Part 922—Dredged Material...

DREDGED MATERIAL PLUME DISPERSAL IN CENTRAL LONG ISLAND SOUND

EPA Science Inventory

A simulation model based upon in situ current velocity data and records of disposal events was developed to predict the chemical exposure field resulting from dredged material disposal plumes in central Long island Sound (CLIS) during the spring of 1983. n the model, plumes are a...

2014 Proposed Determination Pursuant to Section 404c of the Clean Water Act for Pebble Deposit Area, Southwest Alaska

EPA Pesticide Factsheets

EPA Region 10's proposed determination to restrict the use of certain waters in the Bristol Bay watershed for disposal of dredged or fill material associated with mining the Pebble deposit, a large ore body in southwest Alaska.

Beneficial Uses of Dredged Material Fact Sheet: Project Partners and Decision Makers

EPA Pesticide Factsheets

Disposal of dredged material is managed and conducted by federal, state, and local governments; private entities; and semi-private entities. Cooperation among these groups strengthens the possibility that suitable materials will be used beneficially.

Reclamation of abandoned mined lands along th Upper Illinois Waterway using dredged material

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Luik, A; Harrison, W

1982-01-01

Sediments were sampled and characterized from 28 actual or proposed maintenance-dredging locations in the Upper Illinois Waterway, that is, the Calumet-Sag Channel, the Des Plaines River downstream of its confluence with the Calumet-Sag Channel, and the Illinois River from the confluence of the Kankakee and Des Plaines rivers to Havana, Illinois. Sufficient data on chemical constituents and physical sediments were obtained to allow the classification of these sediments by currently applicable criteria of the Illinois Environmental Protection Agency for the identification of hazardous, persistent, and potentially hazardous wastes. By these criteria, the potential dredged materials studied were not hazardous, persistent,more » or potentially hazardous; they are a suitable topsoil/ reclamation medium. A study of problem abandoned surface-mined land sites (problem lands are defined as being acidic and/or sparsely vegetated) along the Illinois River showed that three sites were particularly well suited to the needs of the Corps of Engineers (COE) for a dredged material disposal/reclamation site. Thes sites were a pair of municipally owned sites in Morris, Illinois, and a small corporately owned site east of Ottawa, Illinois, and adjacent to the Illinois River. Other sites were also ranked as to suitability for COE involvement in their reclamation. Reclamation disposal was found to be an economically competitive alternative to near-source confined disposal for Upper Illinois Waterway dredged material.« less

75 FR 54497 - Ocean Dumping; Guam Ocean Dredged Material Disposal Site Designation

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-08

... of special scientific importance, and other legitimate uses of the ocean. Minor short-term... option available since 1997. EPA determined that there is a long-term need for an ocean disposal site... Guam and surrounding waters. This is based on the long-term need to support the Naval and commercial...

Recycling biosolids and lake-dredged materials to pasture-based animal agriculture: Alternative nutrient sources for forage productivity and sustainability

USDA-ARS?s Scientific Manuscript database

Domestic sewage sludge or biosolids and lake-dredged materials are examples of materials that can be used to cut fertilizer costs in pasture-based animal agriculture. Sustainable biosolids and lake-dredged materials management is based upon controlling and influencing the quantity, quality and chara...

Dredging with the Blake

NASA Astrophysics Data System (ADS)

In the early part of the 19th century it was commonly thought that marine life existed only in the upper levels of the oceans. In later years, animals were recovered from successively greater depths, so that by the time of the Challenger expedition in 1873, life seemed to exist almost everywhere in the ocean and on the sea floor. The remarkable abundance of the deep sea fascinated naturalists world-wide, and in 1877 the U.S. Coast Survey steamer Blake was outfitted for deep dredging and trawling, to be done in conjunction with sounding surveys of the eastern U.S. continental shelf and slope. With a waterline length of only 140 feet (43 m), the Blake was a rather small vessel for such arduous service, but these limitations were more than compensated for by Alexander Agassiz, who directed the first dredging survey, and Lieutenant Sigsbee, who commanded the vessel.

Beneficial Uses of Dredged Material Case Study: San Francisco Bay Region

EPA Pesticide Factsheets

A major interagency, regional planning effort led to the development of the Long-Term Management Strategy and other planning programs in the San Francisco Bay area. These programs incorporate beneficial uses of dredged material into local projects.

Beneficial use of dredged materials in Great Lakes commercial ports for transportation projects.

DOT National Transportation Integrated Search

2014-05-01

This report describes an effort to facilitate beneficial use of dredged materials (DM) from Great Lakes ports and harbors as an alternative construction : material in transportation-related earthwork applications. The overall objective is to link tog...

Dredging Operations Technical Support Program. Aquaculture in Dredged Material Containment Areas, Proceedings Held at Galveston, Texas on September 1982.

DTIC Science & Technology

1983-10-01

material 20. AhrlACT Vmrtge m rnp e N neeae md Ideltfy by block number) The view that active dredged material containment areas (DMCA) are unpro... activities to respond to concerns about unreasonable risks caused by incompatibility of DMCA physical, chemical, and operation conditions with aquaculture...grant disposal easements to the CE. This negative view, that active disposal areas are unproductive, commercially unusable, and incompatible with

Monitoring and modeling nearshore dredge disposal for indirect beach nourishment, Ocean Beach, San Francisco

USGS Publications Warehouse

Barnard, Patrick L.; Hanes, Daniel M.; Lescinski, Jamie; Elias, Edwin

2007-01-01

Nearshore dredge disposal was performed during the summer of 2005 at Ocean Beach, San Francisco, CA, a high energy tidal and wave environment. This trial run was an attempt to provide a buffer to a reach of coastline where wave attack during the winter months has had a severe impact on existing sewage infrastructure. Although the subsequent beach response was inconclusive, after one year the peak of the disposal mound had migrated ~100 m toward the shore, providing evidence that annual dredge disposal at this site could be beneficial over the long-term by at the very least providing: 1) additional wave dissipation during storms 2) compatible sediment to feed nearshore bars, 3) sediment cover on an exposed sewage outfall pipe, and 4) a viable alternative to the shoaling offshore disposal site. Numerical modeling suggests that despite the strong tidal currents in the region, wave forcing is the dominant factor moving the sediment slowly toward shore, and placing sediment at just slightly shallower depths (e.g. 9 m) in the future would have a more immediate impact.

Dredging Operations Technical Support Program. General Decisionmaking Framework for Management of Dredged Material: Example Application to Commencement Bay, Washington.

DTIC Science & Technology

1991-06-01

Figure 4) and was used to predict surface runoff water quality from dredged material as part of the CE/EPA FVP ( Westerdahl and Skogerboe 1981; Lee and...Sedimrnts," Miscellaneous Paper D-83-1, US Army Engineer Waterways Experiment Station, Vicksburg, MS. Westerdahl , H. E., and Skogerboe, J. G. 1981

Restoring marsh elevation in a rapidly subsiding salt marsh by thin-layer deposition of dredged material

USGS Publications Warehouse

Ford, M.A.; Cahoon, D.R.; Lynch, J.C.

1999-01-01

Thin-layer deposition of dredged material on coastal marsh by means of high-pressure spray dredging (Jet-Spray??2) technology has been proposed as a mechanism to minimize wetland impacts associated with traditional bucket dredging technologies and to restore soil elevations in deteriorated marshes of the Mississippi River delta. The impact of spray dredging on vegetated marsh and adjacent shallow-water habitat (formerly vegetated marsh that deteriorated to open water) was evaluated in a 0.5-ha Spartina alterniflora-dominated salt marsh in coastal Louisiana. The thickness of dredged sediment deposits was determined from artificial soil marker horizons and soil elevation change was determined from sedimentation-erosion tables (SET) established prior to spraying in both sprayed and reference marshes. The vertical accretion and elevation change measurements were made simultaneously to allow for calculation of shallow (~5 m depth) subsidence (accretion minus elevation change). Measurements made immediately following spraying in July 1996 revealed that stems of S. alterniflora were knocked down by the force of the spray and covered with 23 mm of dredged material. Stems of S. alterniflora soon recovered, and by July 1997 the percent cover of S. alterniflora had increased three-fold over pre-project conditions. Thus, the layer of dredged material was thin enough to allow for survival of the S. alterniflora plants, with no subsequent colonization by plant species typical of higher marsh zones. By February 1998, 62 mm of vertical accretion accumulated at this site, and little indication of disturbance was noted. Although not statistically significant, soil elevation change was greater than accretion on average at both the spray and reference marshes, suggesting that subsurface expansion caused by increased root biomass production and/or pore water storage influence elevation in this marsh region. In the adjacent shallow water pond, 129 mm of sediment was deposited in July

Mechanical and chemical properties of composite materials made of dredged sediments in a fly-ash based geopolymer.

PubMed

Lirer, S; Liguori, B; Capasso, I; Flora, A; Caputo, D

2017-04-15

Dredging activity in harbours and channels produces huge quantities of sediments, generally considered as waste soil (WS) to be disposed: the management of such sediments is a great environmental problem for many countries worldwide. Among the recycling possibilities, the use of dredged sediments for the manufacture of geopolymer-based materials seems to be an interesting alternative to disposal, due to their low cost and easy availability. In order to analyse the possibility to use these geopolymer materials as building materials - for instance as precast construction elements in maritime projects - a multi-disciplinary research activity has been developed at the Federico II University of Napoli (Italy). Some experimental tests have been carried out on different geopolymeric specimens made by mixing sediments from Napoli 'harbour and industrial fly ashes produced by a power plant in the South of Italy. A siliceous sand was used for comparison as an inert reference material. Chemical, morphological and mechanical properties of different specimens have been studied by X-ray diffraction, Scanning Electron Microscopy (SEM), Fourier transformed infrared spectroscopy (FTIR) and finally unconfined compression tests. The experimental results highlight that the use of dredged sediments in combination with fly ash can lead to geopolymeric matrices with interesting mechanical performances. Some differences in the microstructure of the geocomposite built with the siliceous sand or the dredged materials were found. In terms of environmental impacts, on the basis of standard leaching tests and according to Italian thresholds, the adopted dredged mixtures satisfy the prescribed limit for inert or non hazardous waste. Copyright © 2017 Elsevier Ltd. All rights reserved.

Growth and Construction of Oceanic Crust at Atlantis Bank, Southwest Indian Ridge

NASA Astrophysics Data System (ADS)

Schwartz, J. J.; John, B. E.; Cheadle, M. J.; Miranda, E. A.; Grimes, C. B.; Wooden, J. L.; Dick, H. J.

2005-12-01

Magmatic zircon is a common accessory mineral in oceanic crustal rocks including gabbro, oxide gabbro, diabase and felsic veins. Its presence in these rocks provides an exceptional opportunity to document crustal growth processes at slow-spreading mid-ocean ridges. We present nineteen Pb/U zircon SHRIMP-RG ion probe ages of lower crustal rocks collected by manned submersible, ROV, dredging and ODP drilling from a 20 x 30 km2 area of Atlantis Bank, Southwest Indian Ridge, which allow us to constrain the growth and construction of oceanic crust. Weighted average 206Pb/238U ages of these samples range from 10.7 to 13.9 Ma, with errors of 0.1-0.6 m.y. (<1 - 4%). At least 75% of these gabbros accreted within error of the predicted sea-surface magnetic age, whereas up to 25% are between 700,000 and 2.5 m.y. older. In one sample, we identified zircon with inherited cores as much as 1.5 m.y. older than their corresponding rims. There is no observable correlation between age and lithology, and the anomalously old samples are not from any specific part of Atlantis Bank; they appear to be randomly distributed amongst the non-anomalous age samples and come from various structural depths. We consider two models to explain the presence of these anomalously old rocks: i) a stochastic intrusion model whereby magma was intruded at different spatial locations within the rift valley as the plates spread apart, resulting in the entrapment of older lower crust by subsequent intrusions; and/or ii) a model in which some gabbroic bodies originally crystallized at depths of ~5-18 km below the base of the crust in a thick, cold, axial lithosphere and were subsequently uplifted along flow-lines and intruded by shallow-level magmas during the creation of Atlantis Bank. In this model, the difference in time between the Pb/U zircon crystallization age and the magnetic age is a proxy for the depth at which zircon crystallized (assuming a constant mantle upwelling rate during the construction of

Fishery Resource Utilization of a Restored Estuarine Borrow Pit: A Beneficial Use of Dredged Material Case Study

DTIC Science & Technology

2012-08-01

W) is a 75-square-mile shallow estuary located in Ocean County, New Jersey. Situated behind a barrier spit and Long Beach Island, the estuary’s...primary connection to the ocean is via Barnegat Inlet (Figure 1). Dredged Holes #5 and #6 are located less than 30.5 m (100 ft) from shore along the...included oyster toadfish (Opsanus tau) (CPUE = 20-25 fish trawl/hr) and summer flounder (Paralichthys dentatus) (CPUE 8 fish trawl/hr), both of

Summit on the beneficial use of dredged materials : turning a surplus material into a commodity of value.

DOT National Transportation Integrated Search

2014-07-01

Dredged material management options for commercial ports, particularly those involving permanent or long-term placement facilities, are : diminishing. Many existing placement facilities serving these ports are at, or near capacity, and high costs, pl...

The dynamics of fine-grain sediment dredged from Santa Cruz Harbor

USGS Publications Warehouse

Storlazzi, Curt D.; Conaway, Christopher H.; Presto, M. Katherine; Logan, Joshua B.; Cronin, Katherine; van Ormondt, Maarten; Lescinski, Jamie; Harden, E. Lynne; Lacy, Jessica R.; Tonnon, Pieter K.

2011-01-01

In the fall and early winter of 2009, a demonstration project was done at Santa Cruz Harbor, California, to determine if 450 m3/day of predominantly (71 percent) mud-sized sediment could be dredged from the inner portion of the harbor and discharged to the coastal ocean without significant impacts to the beach and inner shelf. During the project, more than 7600 m3 of sediment (~5400 m3 of fine-grain material) was dredged during 17 days and discharged approximately 60 m offshore of the harbor at a depth of 2 m on the inner shelf. The U.S. Geological Survey's Pacific Coastal and Marine Science Center was funded by the U.S. Army Corps of Engineers and the Santa Cruz Port District to do an integrated mapping and process study to investigate the fate of the mud-sized sediment dredged from the inner portion of Santa Cruz Harbor and to determine if any of the fine-grain material settled out on the shoreline and/or inner shelf during the fall and early winter of 2009. This was done by collecting highresolution oceanographic and sediment geochemical measurements along the shoreline and on the continental shelf of northern Monterey Bay to monitor the fine-grain sediment dredged from Santa Cruz Harbor and discharged onto the inner shelf. These in place measurements, in conjunction with beach, water column, and seabed surveys, were used as boundary and calibration information for a three-dimensional numerical circulation and sediment dynamics model to better understand the fate of the fine-grain sediment dredged from Santa Cruz Harbor and the potential consequences of disposing this type of material on the beach and on the northern Monterey Bay continental shelf.

Characterizing Seagrass Exposure to Light Attenuation and Turbidity Associated with Dredging Activity in the Gulf Intracoastal Waterway, Sarasota Bay, Florida

DTIC Science & Technology

2016-11-01

exposure to dredged material plumes. Sarasota Bay, a 56-mile long coastal lagoon located in southwest Florida, stretches from Anna Maria Sound at... Protection classifies the waters of Sarasota Bay and Tampa Bay as Outstanding Florida Waters. Portions of Gulf Intracoastal Waterway (GIWW) that...constructed between 1960 and 1967 (Alperin 1983). The channel between these two rivers was routed east of the barrier islands or keys to protect the

The Role of the Federal Standard in the Beneficial Use of Dredged Material

EPA Pesticide Factsheets

A guide for USACE Districts, other federal agencies, state agencies, local governments, and private interest groups. The Federal Standard Paper provides guidance on using dredged material as a resource to achieve environmental and economic benefits.

Effects of contaminants in dredge material from the Lower Savannah River

USGS Publications Warehouse

Winger, P.V.; Lasier, P.J.; White, D.H.; Seginak, J.T.

2000-01-01

Contaminants entering aquatic systems from agricultural, industrial, and municipal activities are generally sequestered in bottom sediments. The environmental significance of contaminants associated with sediments dredged from Savannah Harbor, Georgia, USA, are unknown. To evaluate potential effects of contaminants in river sediments and sediments dredged and stored in upland disposal areas on fish and wildlife species, solid-phase sediment and sediment pore water from Front River, Back River, an unnamed Tidal Creek on Back River, and Middle River of the distributary system of the lower Savannah River were tested for toxicity using the freshwater amphipod Hyalella azteca. In addition, bioaccumulation of metals from sediments collected from two dredge-disposal areas was determined using the freshwater oligochaete Lumbriculus variegatus. Livers from green-winged teals (Anas crecca) and lesser yellowlegs (Tringa flavipes) foraging in the dredge-spoil areas and raccoons (Procyon lotor) from the dredge-disposal/river area and an upland site were collected for metal analyses. Survival of H. azteca was not reduced in solid-phase sediment exposures, but was reduced in pore water from several locations receiving drainage from dredge-disposal areas. Basic water chemistry (ammonia, alkalinity, salinity) was responsible for the reduced survival at several sites, but PAHs, metals, and other unidentified factors were responsible at other sites. Metal residues in sediments from the Tidal Creek and Middle River reflected drainage or seepage from adjacent dredge-disposal areas, which could potentially reduce habitat quality in these areas. Trace metals increased in L. variegatus exposed in the laboratory to dredge-disposal sediments; As, Cu, Hg, Se, and Zn bioaccumulated to concentrations higher than those in the sediments. Certain metals (Cd, Hg, Mo, Se) were higher in livers of birds and raccoons than those in dredge-spoil sediments suggesting bioavailability. Cadmium, Ct, Hg, Pb

Monitoring of Waves and Currents Near the Alabama Dredged Materials Mounds

DTIC Science & Technology

1994-09-01

34 Coniclusions. .. .. .. .. .. .... .... .... .... .. .... ........ 35 V References...System Design 17 Alm zSm ! , ,- Mi’ 2< 7 _ _ Ii~ ... . . .. I 18 Chapter 5 System Doaign repeated impacts by trawlers. A brief description of the...less than 4 dcg. Chaptor 6 Fioeuits 35 rii ReferencesII Bradley, K. P., and Hands, E. B. (1989). "Dredged material underwater berms." Proceedings of

Solidification of Dredged Sludge by Hydraulic Ash-Slag Cementitious Materials

NASA Astrophysics Data System (ADS)

Zhu, Shu-Jing; Qin, Ying; Hwang, Jiann-Yang

Solidification treatment is used to treat hazardous wastes for disposal and to remediate the contaminated land. It is an increasingly popular technology for redevelopment of brown fields since treated wastes can often be left on-site, which can improve the site's soil for subsequent construction. In order to find home for the dredged sludge from the Pearl River Estuary Channel in China, the potential uses of treated dredged sludge by solidification treatment as valuable structural fill was investigated. Structure fills were prepared under various formula and curing conditions. Modulus of elasticity was detemined at 7 days, 14 days and 28 days with different types of load application. Atterberg limit, compactibility and CBR values are reported. The relationship between the microstructure and engineering properties of treated sludge are examined. The results clearly show the technical benefits by stabilizing soft soils with Hydraulic ash-slag cementitious materials. XRD and DTA-TG tests were carried out on certain samples to characterize the hydraulic compounds formed.

40 CFR 227.13 - Dredged materials.

Code of Federal Regulations, 2013 CFR

2013-07-01

... municipal or industrial wastes or by runoff from terrestrial sources such as agricultural lands. (b) Dredged... energy such as streams with large bed loads or coastal areas with shifting bars and channels; or (2...

40 CFR 227.13 - Dredged materials.

Code of Federal Regulations, 2012 CFR

2012-07-01

... municipal or industrial wastes or by runoff from terrestrial sources such as agricultural lands. (b) Dredged... energy such as streams with large bed loads or coastal areas with shifting bars and channels; or (2...

40 CFR 227.13 - Dredged materials.

Code of Federal Regulations, 2014 CFR

2014-07-01

... municipal or industrial wastes or by runoff from terrestrial sources such as agricultural lands. (b) Dredged... energy such as streams with large bed loads or coastal areas with shifting bars and channels; or (2...

Air- Sea Interactions in the Southwest Tropical Indian Ocean

NASA Astrophysics Data System (ADS)

Burns, J. M.; Bulusu, S.

2016-12-01

The Southwest Tropical Indian Ocean (SWTIO) features a unique, seasonal upwelling of the thermocline also known as the Seychelles-Chagos Thermocline Ridge (SCTR; 55°E-65°E, 5°S-12°S). Past research provides evidence for more tropical cyclone days over the SWTIO during austral summer with a deep thermocline ridge than in austral summer with a shallow thermocline ridge. Normally more cyclones form over the SWTIO when the thermocline is deeper, which has a positive relation to the arrival of downwelling Rossby waves originating in the southeast tropical Indian Ocean due to the anomalous effects of the Indian Ocean Dipole (IOD) and El Niño. With a particular focus on 2012/2013, this study reveals the dynamic properties of the SCTR that play an important role in the modulation of tropical cycles in the SWTIO. In addition to influencing cyclogeneis in the SCTR region, remote processes such as IOD and ENSO are also primary drivers of the SCTR interannual variability with respect to both ocean temperature and salinity.

33 CFR 336.2 - Transportation of dredged material for the purpose of disposal into ocean waters.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Transportation of dredged... provisions of 40 CFR 225.3 are followed and the Administrator grants a waiver of the criteria pursuant to section 103(d) of the ODA. (3) If the regional administrator advises the district engineer that the...

Coastal monitoring of the May 2005 dredge disposal offshore of Ocean Beach, San Francisco, Calif.

USGS Publications Warehouse

Barnard, Patrick L.; Hanes, Daniel M.

2006-01-01

Ocean Beach, California, contains an erosion hot spot in the shadow of the San Francisco ebb tidal delta south of Sloat Boulevard that threatens valuable public infrastructure as well as the safe recreational use of the beach. In an effort to reduce the erosion at this location and avoid hazardous navigation conditions at the current disposal site (SF-8), a new plan for the management of sediment dredged annually from the main shipping channel at the mouth of Francisco Bay was implemented in May 2005 by the United States Army Corps of Engineers, San Francisco District (COE). The objective for COE was to perform a test dredge disposal of ~230,000 m3 (300,000 yd3) of sand just offshore of the erosion hot spot, in depths between approximately 9 and 14 m. This disposal site was chosen because it is in a location where the strong tidal currents associated with the mouth of San Francisco Bay and waves can potentially feed sediment toward the littoral zone in the reach of the beach that is experiencing critical erosion. The onshore migration of sediment from the target disposal location might feed the primary longshore bar or the nearshore zone, and provide a buffer to erosion that peaks during winter months when large waves impact the region. The U.S. Geological Survey (USGS), in collaboration with the Sea Floor Mapping Lab (SFML) of California State University, Monterey Bay, monitored the initial bathymetric evolution of the test dredge disposal site and the adjacent coastal region from May 2005 to November 2005. This paper reports on this monitoring effort and assesses the short-term coastal response.

Automated dredging and disposal alternatives management system (ADDAMS). Environmental effects of dredging. Technical note

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

This technical note describes the current capabilities and availability of the Automated Dredging and Disposal Alternatives Management System (ADDAMS). The technical note replaces the earlier Technical Note EEDP-06-12, which should be discarded. Planning, design, and management of dredging and dredged material disposal projects often require complex or tedious calculations or involve complex decision-making criteria. In addition, the evaluations often must be done for several disposal alternatives or disposal sites. ADDAMS is a personal computer (PC)-based system developed to assist in making such evaluations in a timely manner. ADDAMS contains a collection of computer programs (applications) designed to assist in managingmore » dredging projects. This technical note describes the system, currently available applications, mechanisms for acquiring and running the system, and provisions for revision and expansion.« less

Model and Assessment of the Contribution of Dredged Material Disposal to Sea-Surface Contamination in Puget Sound

DTIC Science & Technology

1986-02-01

DISPOSAL TO SEA-SURFACE CONTAMINATION IN PUGET SOUND J. T., Hardy Marine Research Laboratory Sequim , Washington C. E. Cowan Pacific Northwest Laboratory...spawning season. ( 1 I -"I CONCLUSIONS AND RECOMMENDATIONS Significant SSM contamination and toxicity already exists in Elliott Bay . Dredge dieposal could...disposal area of 900 ft. Typical contaminant concentrations on dredged material and baseline concentrations in the microlayer of Elliott Bay (Hardy et

Sustainable Confined Disposal Facilities for Long-term Management of Dredged Material

DTIC Science & Technology

2010-07-01

need to resort to a full-blown risk assessment . Ideally, a set of look-up criteria could be developed for beneficial use applications where no direct...EPA-905-R-99-006. Assessment and Remediation of Contaminated Sediments Program. Chicago, IL: Great Lakes National Program Office. Olin-Estes, T. J...maintenance dredging Hydrodynamic modeling to assess benefits, adjust cuts, and optimize dredging time intervals Dredge more efficiently Silent

Field Verification Program (Aquatic Disposal). Bioenergetic Effects of Black Rock Harbor Dredged Material on the Polychaete Nephtys incisa: A Field Verification.

DTIC Science & Technology

1988-03-01

observed in the laboratory, and to determine the degree of correlation between the bioaccumulation of contaminants and bioenergetic responses...toxicity of liquid, suspended particulate, and solid phases; (c) estimating the potential contami- nant bioaccumulation ; and (d) describing the initial... bioaccumulation of dredged material contami- nants with biological responses from laboratory and field exposure to dredged material. However, this study

Southwest Pacific Ocean Circulation and Climate Experiment (SPICE) scientific advances and future west pacific coordination

NASA Astrophysics Data System (ADS)

Ganachaud, A. S.; Sprintall, J.; Lin, X.; Ando, K.

2016-02-01

The Southwest Pacific Ocean Circulation and Climate Experiment (SPICE) is an international research program under the auspices of CLIVAR (Climate Variability and Predictability). The key objectives are to understand the Southwest Pacific Ocean circulation and Convergence Zone (SPCZ) dynamics, as well as their influence on regional and basin-scale climate patterns. It was designed to measure and monitor the ocean circulation, and to validate and improve numerical models. South Pacific oceanic waters are carried from the subtropical gyre centre in the westward flowing South Equatorial Current (SEC), towards the southwest Pacific-a major circulation pathway that redistributes water from the subtropics to the equator and Southern Ocean. Water transit through the Coral and Solomon Seas is potentially of great importance to tropical climate prediction because changes in either the temperature or the amount of water arriving at the equator have the capability to modulate ENSO and produce basin-scale climate feedbacks. On average, the oceanic circulation is driven by the Trade Winds, and subject to substantial variability, related with the SPCZ position and intensity. The circulation is complex, with the SEC splitting into zonal jets upon encountering island archipelagos, before joining either the East Australian Current or the New Guinea Costal UnderCurrent towards the equator. SPICE included large, coordinated in situ measurement programs and high resolution numerical simulations of the area. After 8 years of substantial in situ oceanic observational and modeling efforts, our understanding of the region has much improved. We have a refined description of the SPCZ behavior, boundary currents, pathways, and water mass transformation, including the previously undocumented Solomon Sea. The transports are large and vary substantially in a counter-intuitive way, with asymmetries and gating effects that depend on time scales. We will review the recent advancements and discuss

San Francisco Bay Long Term Management Strategy for Dredging

EPA Pesticide Factsheets

The San Francisco Bay Long Term Management Strategy (LTMS) is a cooperative effort to develop a new approach to dredging and dredged material disposal in the San Francisco Bay area. The LTMS serves as the Regional Dredging Team for the San Francisco area.

Flotation as a remediation technique for heavily polluted dredged material. 1. A feasibility study.

PubMed

Cauwenberg, P; Verdonckt, F; Maes, A

1998-01-19

The flotation behaviour of highly polluted dredged material was investigated at different pH values by mechanical agitated (Denver) flotation. Up to 80% of cadmium, copper, lead and zinc could be concentrated in the froth layer which represented only 30% of the total mass. The maximum specificity for heavy metals, defined as the concentrating factor, was obtained at pH 8-9. The maximum recovery of heavy metals on the other hand was found to be reached at elevated pH values (pH 12). In addition the specificity of the flotation process for the transition metals could be assigned to their presence as metal sulphides in the dredged material. However, the interaction with organic matter is an important factor in determining their flotability. The carbonate fraction was irrelevant for the flotation behaviour of heavy metals.

Introduction to Using Native Plant Community on Dredge Material Placement Areas

DTIC Science & Technology

2017-05-01

following: • providing wildlife habitat • inhibiting invasive species establishment • enhancing, structural stability of dikes • providing...areas. Typically, a diked structure is constructed and then filled with dredged material over an extended period of time (i.e., 10–50 years) until...Bourne, Tosin Sekoni, and David Price ERDC/TN EWN-17-2 May 2017 2 DMPA/CDF and are more cost effective to establish than other structural

A new genus and species of Platyischnopidae (Amphipoda: Gammaridea) from the Argentine sea, South-West Atlantic ocean.

PubMed

Chiesa, Ignacio L; Alonso, Gloria M

2014-05-30

The family Platyischnopidae is herein reported for the first time in the Argentine Sea, South-West Atlantic Ocean. A new genus and species, Platyisao holodividum gen. et. sp. nov., collected off the coast of Buenos Aires and Río Negro provinces, is fully described and illustrated. Platyisao gen. nov. is distinguished from the eight other genera of Platyischnopidae by the gnathopods subchelate, and the telson elongate, completely cleft. In addition, the distribution of Tiburonella viscana (Barnard J.L., 1964), up to now known in the South-West Atlantic Ocean from Brazilian waters, is extended to the coast off Buenos Aires province, Argentina.

Tectonic and magmatic processes of the post-spreading ridge in the Southwest Sub-basin, South China Sea

NASA Astrophysics Data System (ADS)

Li, J.; Zhang, J.; Ruan, A.; Niu, X.; Ding, W.

2016-12-01

We report here a 3D ocean bottom seismometer experiment on the fossil spreading ridge in the Southwest Sub-basin of the South China Sea. An extreme asymmetric crustal structure across the axis is revealed and caused by lower crust thinning and upper mantle uplifting located on NW side of the ridge. Such crustal extension proposed a low-angle oceanic detachment fault throughout the whole crust on the last or post spreading stages. A low-velocity (7.6-7.9 km/s) on the uplifting upper mantle is possibly induced by both mantle serpentinization and/or decompression melting through the detachment fault. Velocity models also demonstrate that a post-spreading volcano erupted on the axis is mainly formed by an extrusive process with an extrusive/intrusive ratio of 1.92. Very low velocity of upper crust (3.1-4.8 km/s) of the volcano is attributed to the composition of volcaniclastic rocks and high-porosity basalts, which have been observed in the borehole and dredged samples on the seamounts nearby. KEY WORDS post-spreading ridge; wide-angle seismic refraction; crustal structure; South China Sea; Southwest Sub-basin

40 CFR 227.13 - Dredged materials.

Code of Federal Regulations, 2011 CFR

2011-07-01

... by the U.S. Army Corps of Engineers using the criteria of applicable sections of parts 227 and 228... municipal or industrial wastes or by runoff from terrestrial sources such as agricultural lands. (b) Dredged... phase are those deemed critical by the District Engineer, after evaluating and considering any comments...

Revisions to the Clean Water Act Regulatory Definition of Discharge of Dredged Material; Final Rule

EPA Pesticide Factsheets

The U.S. Army Corps of Engineers (Corps) and the Environmental Protection Agency (EPA) promulgated a final rule Amending a Clean Water Act (CWA) section 404 regulation that defines the term discharge of dredged material.

DETERMINING THE EFFECTIVENESS OF DREDGING: FIELD STUDY FOR EVALUATING DREDGING RESIDUALS

EPA Science Inventory

Dredging is a commonly selected remedy for the risk management of contaminated sediments. Even so, there are questions regarding both the short-term and long-term effectiveness of dredging. A significant aspect in the performance of dredging is dredging residuals. Post-dredging ...

Dredged Material Analysis Tools; Performance of Acute and Chronic Sediment Toxicity Methods

DTIC Science & Technology

2008-07-01

Chronic Sediment Toxicity Methods Jeffery Steevens, Alan Kennedy, Daniel Farrar, Cory McNemar, Mark R. Reiss, Roy K. Kropp, Jon Doi, and Todd Bridges...Environmental Research Program ERDC/EL TR-08-16 July 2008 Revised Dredged Material Analysis Tools Performance of Acute and Chronic Sediment Toxicity ...insight into the potential advan- tages and disadvantages of using chronic sediment toxicity tests with relevant benthic macroinvertebrates as part of

78 FR 37759 - Ocean Dumping; Atchafalaya-West Ocean Dredged Material Disposal Site Designation

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-24

... and Coastal Section (6WQ-EC), Environmental Protection Agency, 1445 Ross Avenue, Suite 1200, Dallas... and Coastal Section (6WQ-EC), Environmental Protection Agency, Region 6, 1445 Ross Avenue, Dallas... ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 228 [EPA-R06-OW-2013-0221; FRL-9826-6] Ocean Dumping...

Variability in tropical cyclone heat potential over the Southwest Indian Ocean

NASA Astrophysics Data System (ADS)

Malan, N.; Reason, C. J. C.; Loveday, B. R.

2013-12-01

Tropical cyclone heat potential (TCHP) has been proposed as being important for hurricane and typhoon intensity. Here, a climatology of TCHP is developed for the Southwest Indian Ocean, a basin that experiences on average 11-12 tropical cyclones per year, many of which impact on Mauritius, Reunion and Madagascar, and Mozambique. SODA data and a regional ocean model forced with the GFDL-CORE v.2b reanalysis winds and heat fluxes are used to derive TCHP values during the 1948-2007 period. The results indicate that TCHP increases through the austral summer, peaking in March. Values of TCHP above 40 kJ cm-2, suggested as the minimum needed for tropical cyclone intensification, are still present in the northern Mozambique Channel in May. A time series of TCHP spatially averaged over the Seychelles-Chagos thermocline ridge (SCTR), an important area for tropical cyclones, is presented. The model time series, which agrees well with XBT-based observations (r = 0.82, p = 0.01), shows considerable interannual variability overlaying an upward tendency that matches with an observed increase in severe tropical cyclone days in the Southwest Indian Ocean. Although an increase in severe storms is seen during 1997-2007, the increasing TCHP tendency time series after 1997 coincides with a decrease in total cyclone numbers, a mismatch that is ascribed to increased atmospheric anticyclonicity over the basin. Seasons of increased (decreased) TCHP over the SCTR appear to be associated with dry (wet) conditions over certain areas of southern and East Africa and are linked with changes in zonal wind and vertical motion in the midtroposphere.

Dungeness crab survey for the Southwest Ocean Disposal Site off Grays Harbor, Washington, June 1990

DOE Office of Scientific and Technical Information (OSTI.GOV)

Higgins, B.J.; Pearson, W.H.

1991-09-01

As part of the Grays Harbor Navigation Improvement Project, the Seattle District of the US Army Corps of Engineers has begun active use of the Southwest Ocean Disposal Site off Grays Harbor, Washington. This survey was to verify that the location of the area of high crab density observed during site selection surveys has not shifted into the Southeast Ocean Disposal Site. In June 1990, mean densities of juvenile Dungeness crab were 146 crab/ha within the disposal site and 609 crab/ha outside ad north of the disposal site. At nearshore locations outside the disposal site, juvenile crab density was 3275more » crab/ha. Despite the low overall abundance, the spatial distribution of crab was such that the high crab densities in 1990 have remained outside the Southwest Ocean Disposal Site. The survey data have confirmed the appropriateness of the initial selection of the disposal site boundaries and indicated no need to move to the second monitoring tier. 8 refs., 9 figs., 2 tabs.« less

Formation of an ultramafic seafloor at the Southwest Indian Ridge 62°-65°E : internal structure of detachment faults and sparse volcanism documented by sidescan sonar and dredges

NASA Astrophysics Data System (ADS)

Cannat, M.; Sauter, D.; Rouméjon, S.

2012-12-01

In october 2010, the Smoothseafloor cruise (RV Marion Dufresne ) documented the continuous exposure, for the past 10 myrs, of mantle-derived ultramafic rocks in the seafloor of the ultra-slow Southwest Indian Ridge in two 50 to 100 km-wide magma-poor corridors centered respectively at 62°30'E and 64°35'E. The proposed interpretation (Sauter et al., AGU abstract 2011) involves successive large offset normal faults (or detachments) that expose ultramafic rocks alternatively in the southern (Antarctic), then in the northern (African) plates. In this presentation we focus on the most recent, near axis regions in these two ultramafic seafloor corridors. We show details of the sidescan sonar images with smooth, non-corrugated exposed detachment surfaces, and an intriguing pattern of pluridecameter-thick and locally anastomozing reflective and less reflective layers in the detachments footwall. Based on preliminary microstructural observations made on samples dredged in the same region, we tentatively interpret these layers as due to contrasted patterns of deformation in the ultramafics next to the fault. Testing this interpretation would be an attractive goal for future submersible and drilling cruises. Deformation types documented in the dredge samples range from heterogeneous plastic to semi-brittle deformation of the primary peridotite mineralogy, to brittle deformation of serpentinized ultramafic rocks. Magmatic rocks make less than 5% of the overal volume of our near axis dredges. These include variably sheared metagabbros, and unmetamorphosed balsalts. Sidescan sonar images show that these basalts form a thin (<200 m) highly discontinuous carapace over the exposed detachments. We show that these basalts are preferentially located along moderate offset normal faults that cut the detachments, or next to inferred breakaways. This observation leads us to propose a link between axial faulting and volcanism in these magma-poor sections of the ultra-slow spreading

Impacts of aggregate dredging on sediment composition and associated benthic fauna at an offshore dredge site in the southern North Sea.

PubMed

Robinson, J E; Newell, R C; Seiderer, L J; Simpson, N M

2005-07-01

Dredging and associated screening at a dredge site in the southern North Sea (Area 408) is associated with areas of well-sorted fine sand that extend for up to 3 km to the south-east of the dredged area and overlay sediments with a more variable particle size composition. This well-sorted fine sand may reflect deposition and transport of material mobilised by the dredging and screening processes at the dredge site. Multivariate analysis of the benthic community structure suggests that marine aggregate dredging, at the level of intensity employed in the study area prior to sample collection, has had a limited impact on benthic community composition compared with that reported from studies elsewhere. This is ascribed to the likely rapid rates of recolonisation by the mobile opportunistic polychaetes and crustaceans that dominate the macrofauna of the sandy gravel deposits at this particular dredge site. Analysis of variance showed, however, that significant differences existed between the sample treatments in terms of species evenness (Pielou's J). Dredged samples were found to have the lowest mean species evenness (0.71) when compared to controls (0.77). The present study highlights the inherent difficulties in the application of general impact/recovery predictions to dredged sites with varying environmental characteristics.

Field Verification Program (Aquatic Disposal). A Field and Laboratory Study Using Adenylate Energy Charge as an Indicator of Stress in Mytilus edulis and Nephtys incisa Treated with Dredged Material.

DTIC Science & Technology

1988-06-01

USING ADENYLATE ENERGY CHARGE AS AN INDICATOR OF STRESS IN MYTILUS EDULIS AND NEPHTYS INCISA TREATED WITH DREDGED MATERIAL hy Gerald E- Zaroogian...of Stress in Mytilus edulis and Nephtys incisa Treated with Dredged Material" TO: All Report Recipients 1.. This is one in a series of scientific...STUDY USING ADENYLATE ENERGY CHPRGE AS AN INDICATOR OF STRESS IN MYTILUS EDULIS AND NEPHTYS INCISA TREATED WITH DREDGED MATERIAL PART I: INTRODUCTION

A quantitative analysis of naiad mollusks from the Prairie du Chien, Wisconsin dredge material site on the Mississippi River

USGS Publications Warehouse

Havlik, M.E.; Marking, L.L.

1980-01-01

The Prairie du Chien dredge material site contains about 100,000 cubic meters of material dredged from the East Channel of the Mississippi Riverin1976. Previous studies in that area suggested a rich molluscan fauna, but most studies were only qualitative or simply observations. Our study of this material was designed to determine the density and diversity of molluscan fauna, to assess changes in the fauna, to identify endemic species previously unreported, and to evaluate the status of the endangered Lampsilis higginsi. Ten cubic meters of dredge material were sieved to recover shells. Molluscan fauna at the site contained38 species of naiades and up to 1,737 identifiable valves per cubic meter. The endangered L. higginsi ranked18th In occurrence, accounted for only 0.52% of the identifiable shells, and averaged about three valves per cubic meter. From a total of 813 kg of naiades and gastropods, 6,339 naiad valves were identified. Five naiad species were collected at the site for the first time, and Eploblasma triquetra had not been reported previously in the Prairie du Chien area. Although the molluscan fauna has changed, the East Channel at Prairie du Chien is obviously suitable for L. higginsi.

Three-dimensional visualization maps of suspended-sediment concentrations during placement of dredged material in 21st Avenue West Channel Embayment, Duluth-Superior Harbor, Duluth, Minnesota, 2015

USGS Publications Warehouse

Groten, Joel T.; Ellison, Christopher A.; Mahoney, Mollie H.

2016-06-30

Excess sediment in rivers and estuaries poses serious environmental and economic challenges. The U.S. Army Corps of Engineers (USACE) routinely dredges sediment in Federal navigation channels to maintain commercial shipping operations. The USACE initiated a 3-year pilot project in 2013 to use navigation channel dredged material to aid in restoration of shoreline habitat in the 21st Avenue West Channel Embayment of the Duluth-Superior Harbor. Placing dredged material in the 21st Avenue West Channel Embayment supports the restoration of shallow bay aquatic habitat aiding in the delisting of the St. Louis River Estuary Area of Concern.The U.S. Geological Survey, in cooperation with the USACE, collected turbidity and suspended-sediment concentrations (SSCs) in 2014 and 2015 to measure the horizontal and vertical distribution of SSCs during placement operations of dredged materials. These data were collected to help the USACE evaluate the use of several best management practices, including various dredge material placement techniques and a silt curtain, to mitigate the dispersion of suspended sediment.Three-dimensional visualization maps are a valuable tool for assessing the spatial displacement of SSCs. Data collection was designed to coincide with four dredged placement configurations that included periods with and without a silt curtain as well as before and after placement of dredged materials. Approximately 230 SSC samples and corresponding turbidity values collected in 2014 and 2015 were used to develop a simple linear regression model between SSC and turbidity. Using the simple linear regression model, SSCs were estimated for approximately 3,000 turbidity values at approximately 100 sampling sites in the 21st Avenue West Channel Embayment of the Duluth-Superior Harbor. The estimated SSCs served as input for development of 12 three-dimensional visualization maps.

Effects of long-term dumping of harbor-dredged material on macrozoobenthos at four disposal sites along the Emilia-Romagna coast (Northern Adriatic Sea, Italy).

PubMed

Simonini, R; Ansaloni, I; Cavallini, F; Graziosi, F; Iotti, M; Massamba N'siala, G; Mauri, M; Montanari, G; Preti, M; Prevedelli, D

2005-12-01

Sediment from harbors of the Emilia-Romagna (Northern Adriatic Sea) were dredged and dumped in four disposal areas characterized by muddy bottoms. The long-term effects of the dumping on macrozoobenthic communities were investigated before and after 6 month, 8 month, 2 years and 4 years. The disposal of dredged material did not influence the granulometry and %TOC in the sediment, and no alterations in the structure of the macrobenthic communities were observed in the four areas. The lack of impact could be ascribed to the environmental characteristics and precautionary measures taken to minimize the effects of the dumping. It appears that: (1) the communities of the dumping areas are well adapted to unstable environments; (2) the sediments were disposed gradually and homogeneously over relatively large areas; Other factors that help to reduce the impact of sediment disposal are the low concentrations of contaminants in dredged materials and the similarity of sediment in the dredged and disposal areas. Off-shore discharge appears a sustainable strategy for the management of uncontaminated dredged sediments from the Northern Adriatic Sea harbors.

Analysis of decision support system for dredging operations management.

DOT National Transportation Integrated Search

2005-12-01

This research developed an improved method for optimizing the disposal of dredged material : at offshore disposal sites. A nonlinear programming model has been developed to assist in : the development of dredging plans at open water disposal sites. T...

Evaluation of dredged material proposed for ocean disposal from Gravesend Bay Anchorage, New York

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barrows, E.S.; Gruendell, B.D.

1996-09-01

The Gravesend Bay Anchorage was one of seven waterways that the US Army Corps of Engineers-New York District (USACE-NYD) requested the Battelle Marine Sciences Laboratory (MSL) to sample and evaluate for dredging and disposal in February 1994. Sediment samples were submitted for physical and chemical analyses to provide baseline sediment chemistry data on the Gravesend Bay Anchorage. Individual sediment core samples collected at the Gravesend Bay Anchorage were analyzed for grain size, moisture content, and total organic carbon (TOC). Two samples, one of composited sediment cores representing the southeast corner of the anchorage (COMP GR), and one sediment core representingmore » the northeast corner of the anchorage (Station GR-1 0), were analyzed for bulk density, specific gravity, metals, chlorinated pesticides, polychlorinated biphenyl (PCB) congeners, polynuclear aromatic hydrocarbons (PAH), and 1,4-dichlorobenzene.« less

Effects of Black Rock Harbor Dredged Material on the Scope for Growth of the Blue Mussel, Mytilus edulis after Laboratory and Field Exposures

DTIC Science & Technology

1987-09-01

aromatic petroleum hydrocarbon exposure concentrations in mussels. In the field, Widdows, Phelps, and 13 Galloway (1981) reported a decrease in the SFG of...from bioaccumulation of dredged material contami- nants with biological responses from laboratory and field exposure to dredged material. However, this...polychaete Neph’tys incisa and the bivalve molluscs Nucuta pr’oxirna and Yo~dia limatula. 9 8. The FVP disposal site was selected within the CLIS so as

Admixing dredged marine clay with cement-bentonite for reduction of compressibility

NASA Astrophysics Data System (ADS)

Rahilman, Nur Nazihah Nur; Chan, Chee-Ming

2017-11-01

Cement-based solidification/stabilization is a method that is widely used for the treatment of dredged marine clay. The key objective for solidification/stabilization is to improve the engineering properties of the originally soft, weak material. Dredged materials are normally low in shear strength and bearing capacity while high incompressibility. In order to improve the material's properties for possible reuse, a study on the one-dimensional compressibility of lightly solidified dredged marine clay admixed with bentonite was conducted. On the other hand, due to the viscous nature, particularly the swelling property, bentonite is a popular volumising agent for backfills. In the present study, standard oedometer test was carried out to examine the compressibility of the treated sample. Complementary strength measurements were also conducted with laboratory vane shear setup on both the untreated and treated dredged marine clay. The results showed that at the same binder content, the addition of bentonite contributed significantly to the reduction of compressibility and rise in undrained shear strength. These improved properties made the otherwise discarded dredged marine soils potentially reusable for reclamation works, for instance.

Annual Reports Regarding Progress in Developing a Dredged Material Management Plan for the Long Island Sound Region

EPA Pesticide Factsheets

The site designation for the Western and Central Long Island Sound disposal sites requires the completion of a Dredged Material Management Plan (DMMP) and EPA to conduct an annual review of progress toward completion of the DMMP.

Feasibility of Using Dredged Mud for Prepared the Permeable Brick

NASA Astrophysics Data System (ADS)

Zhou, Chaoqun; Cheng, Xiaosu; Zeng, Lingke; Wang, Hui; Chen, Jing

2017-10-01

Through experimental analysis found that the chemical composition of the dredged mud is similar to clay and the dredged mud does not leach heavy metals. Using the dredged mud in the preparation of permeable bricks reduced the quantity of incineration dredged mud buried in landfills, and the exploitation and consumption of natural sandstone. The dredged mud needs to be checked by the validation criteria when the second use, so we used the TCLP test to identify hazardous materials. Its leaching of heavy metals was in line with industry standard. And the basic formula of permeable brick were prepared, its performance was in line with national standards. The use of dredged mud preparing eco-friendly permeable bricks, not only solves the problem of environmental pollution, but also gets some economic and social profit.

Containment Area Aquaculture Program. Economics and Marketing of Aquaculture in Dredged Material Containment Areas

DTIC Science & Technology

1993-09-01

project shrimp farm and to use the information learned from the demonstration to examine the economic feasibility of aquaculture in dredged material...aquaculture within the USACE. The Containment Area Aquaculture Program (CAAP) was thus initiated in 1986, as a development of the Environmental ...company. The work of Mariquest was completed in 1989 by Cultured Seafood Group, Inc., Laguna Vista, TX. The

Framework for Comparative Risk Analysis of Dredged Material Disposal Options.

DTIC Science & Technology

1986-10-01

TC3898-62 DACU67-85-D-8829 UNCLASSIFIED F/G 24/3 NL 125 ൖ ൘ ilil;1III -I uPSDDAR UTReports m ~ Puget Sound Dredged DipslAnalysis e~ od Washington State...I rB T T for Puget Sound Dredged Disposal Analysis c/o U.S. Army Corps of Engineers Seattle District 1 A" October, 1986 l-jq .__ .. _ Tetra Tech, Inc...priority pollutants C-2 E-1 Hypothetical example of total or bulk contaminant concentrations in four Puget Sound sediments E-1 E-2 ’Hypothetical example

Assessment of ecotoxicological risks related to depositing dredged materials from canals in northern France on soil.

PubMed

Perrodin, Yves; Babut, Marc; Bedell, Jean-Philippe; Bray, Marc; Clement, Bernard; Delolme, Cécile; Devaux, Alain; Durrieu, Claude; Garric, Jeanne; Montuelle, Bernard

2006-08-01

The implementation of an ecological risk assessment framework is presented for dredged material deposits on soil close to a canal and groundwater, and tested with sediment samples from canals in northern France. This framework includes two steps: a simplified risk assessment based on contaminant concentrations and a detailed risk assessment based on toxicity bioassays and column leaching tests. The tested framework includes three related assumptions: (a) effects on plants (Lolium perenne L.), (b) effects on aquatic organisms (Escherichia coli, Pseudokirchneriella subcapitata, Ceriodaphnia dubia, and Xenopus laevis) and (c) effects on groundwater contamination. Several exposure conditions were tested using standardised bioassays. According to the specific dredged material tested, the three assumptions were more or less discriminatory, soil and groundwater pollution being the most sensitive. Several aspects of the assessment procedure must now be improved, in particular assessment endpoint design for risks to ecosystems (e.g., integration of pollutant bioaccumulation), bioassay protocols and column leaching test design.

New Bedford Harbor Superfund Project Acushnet River Estuary Engineering Feasibility Study of Dredging and Dredged Material Disposal Alternatives. Report 10. Evaluation of Dredging and Dredging Control Technologies

DTIC Science & Technology

1988-11-01

position and pulled through the sediment. Different opening configurations can be used to suit the sediment being removed (Figure 8). 42. The AMTEC ...associated with the New Bedford Harbor site and the relatively large minimum working depth of the AMTEC pneumatic system, this type of dredging

Dredging and disposal of fine sediments in the state of Rio de Janeiro, Brazil.

PubMed

Barbosa, M C; de Souza Soares de Almeida, M

2001-07-30

Dredging is employed quite frequently in the state of Rio de Janeiro, especially for the installation and upkeep of commercial ports and rehabilitation of the hydraulic section of silted bodies of water. Until recently, all dredged material with no economic use was destined for marine disposal or stored at the edge of the water body. Since the 1990s, however, a new approach has been adopted for dredging as a result of pressure from the environmental organisations, encouraging closer interaction in Rio de Janeiro between the local and state public authorities and the universities on issues relating to licensing of this kind of activity. The recent experiments of the Civil and Ocean Engineering Programs of COPPE-UFRJ (Federal University of Rio de Janeiro) described herein are included in this context. The state of Rio de Janeiro has three bays, several coastal lagoon systems and a number of small and medium sized rivers in or close to urban areas, with a gentle slope as they near the sea. This is, then, a region highly susceptible to silting processes of water bodies, and therefore, to maintenance and/or environmental rehabilitation. As discussed in the article, fine and almost always organic sediments prevail, which is a considerable obstacle to the end disposal and possibility of reuse.

A Glimpse at Late Mesozoic to Early Tertiary Offshore Stratigraphy from Wilkes Land, East Antarctica: Results of Strategic Dredging of the Mertz-Ninnis Trough

NASA Astrophysics Data System (ADS)

Schrum, H.; Domack, E.; Desantis, L.; Leventer, A.; McMullen, K.; Escutia, C.

2004-12-01

As early as 1912 Sir Douglas Mawson demonstrated that pre-glacial sedimentary successions could be recovered by seafloor dredging of erosional troughs found offshore, East Antarctica. Since then, little systematic dredging has been undertaken in Antarctica despite indications of outcropping strata exposed along seaward flanks of glacially excavated troughs and the dire need to resolve the nature of preglacial and synglacial strata in this region. During cruise NB Palmer 01-01, three dredges were collected in echelon along the seaward flank of the Mertz-Ninnis Trough, parallel to the Mertz Ice Tongue, in water depths of 900 to 450 m. We combine biostratigraphic (palynologic) and lithologic analyses on sedimentary clasts with multi- and single-channel seismic reflection data collected by the WEGA cruise in 2000. 1359 pebble to cobble sized clasts were collected from three dredges. Of these 15% to 43%, within each dredge, were of sedimentary character, including carbonaceous sandstones with plant macrofossils, black sulfide-rich mudstones, siltstones, lignites, red quartz arenites, arkoses, and diamictites in various states of lithification. Palynomorphs were separated from these sedimentary rocks. We examined eleven individual lithologies, nine of which yielded useful palynological detritus. Of these samples, five yielded palynomorphs distinctive to the Paleogene (i.e. Nothofagus flemingii, Tricolporites spp., Proteacidites spp.); two samples contained only Lower Cretaceous palynomorphs, while three samples provided no stratigraphically useful palynomorph kerogen. We combine these results with multi-channel seismic and multibeam swath mapping to demonstrate that dredged materials represent seafloor outcrop or shallow subcrop of strata beneath a thin glacial till. Our stratigraphic model for these samples is consistent with 62 km of multichannel seismic reflection data (WEGA line W02) showing seaward dipping strata onlapping the basement to the southwest and partly

The potential hydrothermal systems unexplored in the Southwest Indian Ocean

NASA Astrophysics Data System (ADS)

Suo, Yanhui; Li, Sanzhong; Li, Xiyao; Zhang, Zhen; Ding, Dong

2017-06-01

Deep-sea hydrothermal vents possess complex ecosystems and abundant metallic mineral deposits valuable to human being. On-axial vents along tectonic plate boundaries have achieved prominent results and obtained huge resources, while nearly 90% of the global mid-ocean ridge and the majority of the off-axial vents buried by thick oceanic sediments within plates remain as relatively undiscovered domains. Based on previous detailed investigations, hydrothermal vents have been mapped along five sections along the Southwest Indian Ridge (SWIR) with different bathymetry, spreading rates, and gravity features, two at the western end (10°-16°E Section B and 16°-25°E Section C) and three at the eastern end (49°-52°E Section D, 52°-61°E Section E and 61°-70°E Section F). Hydrothermal vents along the Sections B, C, E and F with thin oceanic crust are hosted by ultramafic rocks under tectonic-controlled magmatic-starved settings, and hydrothermal vents along the Section D are associated with exceed magmatism. Limited coverage of investigations is provided along the 35°-47°E SWIR (between Marion and Indomed fracture zones) and a lot of research has been done around the Bouvet Island, while no hydrothermal vents has been reported. Analyzing bathymetry, gravity and geochemical data, magmatism settings are favourable for the occurrence of hydrothermal systems along these two sections. An off-axial hydrothermal system in the southern flank of the SWIR that exhibits ultra-thin oceanic crust associated with an oceanic continental transition is postulated to exist along the 100-Ma slow-spreading isochron in the Enderby Basin. A discrete, denser enriched or less depleted mantle beneath the Antarctic Plate is an alternative explanation for the large scale thin oceanic crust concentrated on the southern flank of the SWIR.

Crustal structure of the Agulhas Ridge (South Atlantic Ocean): Formation above a hotspot?

NASA Astrophysics Data System (ADS)

Jokat, Wilfried; Hagen, Claudia

2017-10-01

The southern South Atlantic Ocean contains several features believed to document the traces of hotspot volcanism during the early formation of the ocean basin, namely the Agulhas Ridge and the Cape Rise seamounts located in the southeast Atlantic between 36°S and 50°S. The Agulhas Ridge parallels the Agulhas-Falkland Fracture Zone, one of the major transform zones of the world. The morphology of the ridge changes dramatically from two parallel segments in the southwest, to the broad plateau-like Agulhas Ridge in the northeast. Because the crustal fabric of the ridge is unknown relating its evolution to hotspots in the southeast Atlantic is an open question. During the RV Polarstern cruise ANT-XXIII-5 seismic reflection and refraction data were collected along a 370 km long profile with 8 Ocean Bottom Stations to investigate its crustal fabric. The profile extends in NNE direction from the Agulhas Basin, 60 km south of the Agulhas Ridge, and continues into the Cape Basin crossing the southernmost of the Cape Rise seamounts. In the Cape Basin we found a crustal thickness of 5.5-7.5 km, and a velocity distribution typical for oceanic crust. The Cape Rise seamounts, however, show a higher velocity in comparison to the surrounding oceanic crust and the Agulhas Ridge. Underplated material is evident below the southernmost of the Cape Rise seamounts. It also has a 5-8% higher density compared to the Agulhas Plateau. The seismic velocities of the Agulhas Ridge are lower, the crustal thickness is approximately 14 km, and age dating of dredge samples from its top provides clear evidence of rejuvenated volcanism at around 26 Ma. Seismic data indicate that although the Cape Rise seamounts formed above a mantle thermal anomaly it had a limited areal extent, whereas the hotspot material that formed the Agulhas Ridge likely erupted along a fracture zone.

Application of the Geophysical Scale Multi-Block Transport Modeling System to Hydrodynamic Forcing of Dredged Material Placement Sediment Transport within the James River Estuary

NASA Astrophysics Data System (ADS)

Kim, S. C.; Hayter, E. J.; Pruhs, R.; Luong, P.; Lackey, T. C.

2016-12-01

The geophysical scale circulation of the Mid Atlantic Bight and hydrologic inputs from adjacent Chesapeake Bay watersheds and tributaries influences the hydrodynamics and transport of the James River estuary. Both barotropic and baroclinic transport govern the hydrodynamics of this partially stratified estuary. Modeling the placement of dredged sediment requires accommodating this wide spectrum of atmospheric and hydrodynamic scales. The Geophysical Scale Multi-Block (GSMB) Transport Modeling System is a collection of multiple well established and USACE approved process models. Taking advantage of the parallel computing capability of multi-block modeling, we performed one year three-dimensional modeling of hydrodynamics in supporting simulation of dredged sediment placements transport and morphology changes. Model forcing includes spatially and temporally varying meteorological conditions and hydrological inputs from the watershed. Surface heat flux estimates were derived from the National Solar Radiation Database (NSRDB). The open water boundary condition for water level was obtained from an ADCIRC model application of the U. S. East Coast. Temperature-salinity boundary conditions were obtained from the Environmental Protection Agency (EPA) Chesapeake Bay Program (CBP) long-term monitoring stations database. Simulated water levels were calibrated and verified by comparison with National Oceanic and Atmospheric Administration (NOAA) tide gage locations. A harmonic analysis of the modeled tides was performed and compared with NOAA tide prediction data. In addition, project specific circulation was verified using US Army Corps of Engineers (USACE) drogue data. Salinity and temperature transport was verified at seven CBP long term monitoring stations along the navigation channel. Simulation and analysis of model results suggest that GSMB is capable of resolving the long duration, multi-scale processes inherent to practical engineering problems such as dredged material

Environmental management for dredging sediments - the requirement of developing nations.

PubMed

Manap, Norpadzlihatun; Voulvoulis, Nikolaos

2015-01-01

Scientific research has characterized the effects of dredging, an underwater excavation process for navigational purposes or material extraction, and has shown its association with a number of chemical, physical and biological impacts. Due to this, much environmental management has been applied in the dredging industry in order to manage its detrimental effects. However, developing nations may have different approaches towards their dredging environmental management to compare to their companions with higher economic strength. Moreover, scientific evidence to make an informed decision is often lacking, hence affecting the number of research executed at these nations, limiting their efforts to preserve the environment. This paper reviews the dredging environmental impacts and its two important factors, dredging technology and sediment characteristic, that determine the magnitude of impacts through literature review, and discusses the need for a more integrated dredging environmental management to be developed for developing nations. Copyright © 2014 Elsevier Ltd. All rights reserved.

Accumulation by fish of contaminants released from dredged sediments

USGS Publications Warehouse

Seelye, James G.; Hesselberg, Robert J.; Mac, Michael J.

1982-01-01

Inasmuch as the process of dredging and disposing of dredged materials causes a resuspension of these materials and an increase in bioavailability of associated contaminants, we conducted a series of experiments to examine the potential accumulation by fish of contaminants from suspended sediments. In the first experiment we compared accumulation of contaminants by yellow perch of hatchery and lake origin and found that after 10 days of exposure to nonaerated sediments, fish of hatchery origin accumulated PCBs and Fe, while fish of lake origin accumulated As, Cr, Fe, and Na. Two additional exposures were conducted to evaluate the effects of aerating the sediments prior to measuring bioavailability of associated contaminants. Fish of hatchery origin exposed to nonaerated sediments for 10 days accumulated PCBs and Hg, while fish of hatchery origin exposed to aerated sediments for 10 days accumulated PCBs, DDE, Zn, Fe, Cs, and Se. These results demonstrated not only the potential for uptake of contaminants by fish as a result of dredging but also the potential utility of fish bioassays in evaluating proposed dredging operations.

Assessment of the Effectiveness of Environmental Dredging in South Lake, China

NASA Astrophysics Data System (ADS)

Wang, Xiao Yu; Feng, Jiang

2007-08-01

Environmental dredging is a primary remedial option for removal of the contaminated material from aquatic environment. Of primary concern in environmental dredging is the effectiveness of the intended sediment removal. A 5-year field monitoring study was conducted to assess the effectiveness of the environmental dredging in South Lake, China. The concentrations of total nitrogen (TN), total phosphors, and heavy metals (Zn, Pb, Cd, Cu, Cr, Ni, Hg, and As) before and after dredging in sediment were determined and compared. Multiple ecological risk indices were employed to assess the contamination of heavy metals before and after dredging. Our results showed that the total phosphorus levels reduced 42% after dredging. Similar changes for Hg, Zn, As Pb, Cd, Cu, Cr, and Ni were observed, with reduction percentages of 97.0, 93.1, 82.6, 63.9, 52.7, 50.1, 32.0, and 23.6, respectively, and the quality of sediment improved based on the criterion of Sediment Quality Guidelines by USEPA and contamination degree values (Cd) decreased significantly (paired t-test, p < 0.05). Unexpectedly, the TN increased 49% after dredging compared to before dredging. Findings from the study demonstrated that the environmental dredging was an effective mechanism for removal of total phosphorus and heavy metals from South Lake. Nevertheless, the dredging was ineffective to remove total nitrogen from sediment. We conclude that the reason for the observed increase in TN after dredging was likely ammonia release from the sediment impairing the dredging effectiveness.

Comprehensive Analysis of Migration Pathways (CAMP): Contaminant Migration Pathways at Confined Dredged Material Disposal Facilities

DTIC Science & Technology

1990-09-01

fluctuating flow rates make such approximations relatively inexact. Accuracy of mass loading estimates can be improved by increasing the number of...Engler, Patin, and Theriot 1988; Patin and Baylot 1989). 26. Effluent flow from an upland CDF is highest when large quantities of water are being...dispersion in conjunction with lower flows during placement of mechanical dredged material. Interactions between sediment and water that occur during

Calls reveal population structure of blue whales across the southeast Indian Ocean and the southwest Pacific Ocean.

PubMed

Balcazar, Naysa E; Tripovich, Joy S; Klinck, Holger; Nieukirk, Sharon L; Mellinger, David K; Dziak, Robert P; Rogers, Tracey L

2015-11-24

For effective species management, understanding population structure and distribution is critical. However, quantifying population structure is not always straightforward. Within the Southern Hemisphere, the blue whale ( Balaenoptera musculus ) complex is extremely diverse but difficult to study. Using automated detector methods, we identified "acoustic populations" of whales producing region-specific call types. We examined blue whale call types in passive acoustic data at sites spanning over 7,370 km across the southeast Indian Ocean and southwest Pacific Ocean (SWPO) from 2009 to 2012. In the absence of genetic resolution, these acoustic populations offer unique information about the blue whale population complex. We found that the Australian continent acts as a geographic boundary, separating Australia and New Zealand blue whale acoustic populations at the junction of the Indian and Pacific Ocean basins. We located blue whales in previously undocumented locations, including the far SWPO, in the Tasman Sea off the east coast of Australia, and along the Lau Basin near Tonga. Our understanding of population dynamics across this broad scale has significant implications to recovery and conservation management for this endangered species, at a regional and global scale.

Bivalve embryo bioassay to assess the potential toxicity of dredged material before dumping

DOE Office of Scientific and Technical Information (OSTI.GOV)

Quiniou, F.

1995-12-31

Dredged harbor sediments frequently contain a wide spectrum of contaminants in addition to a significant percentage of organic matter. Also, dredging and dumping activities into sea water, of these highly contaminated soil may induce a harmful effect on the environment. In France, in accordance with Oslo convention guidelines, a working group on dredging activities and environment (GEODE) created since 1991 decided to set up a pilot research program to assess the intrinsic toxicity of four harbor sludges. Intrinsic toxicity of harbor muds were tested by solid phase (whole sediment) and aqueous extract bioassays (sea water elutriates) using the sublethal toxicitymore » test bivalve embryo bioassay (Crassostrea gigas). Elutriates enable them to detect the toxicity of contaminants which may be released in the soluble form into the water column during dredging operations. While, whole sediment integrate the synergistic effects of all the contaminants (hydrophilic and hydrophobic) including pore water. Bioassays results, correlated to chemical analysis, are compared to contaminant levels determined by French working group GEODE and Canadian sediment quality criteria.« less

Dredged Material Disposal Study, U.S. Navy Home Port, Everett, Washington. Technical Supplement.

DTIC Science & Technology

1987-09-01

Group (CVBG) Home Port at Puget Sound in the east waterway of Everett Harbor, Washington (Fig- ure 1). Construction of the home port facility will...significant portion of the material remains in "clumps." This situation is especially true for the Puget Sound area, where much of the dredging is done...0; P’RFOPM %G ORCA % 2A-ON 60 0 CE SYMBOL 7a NAME OF %𔃺’OR .G ORGAN ZATON, ’, .. ’\\VES 1 (It applicable) Hv.drauli’s Laboratory WESHE 5c ADDRESS Ccty

Procedural Guide for Designation Surveys of Ocean Dredged Material Disposal Sites.

DTIC Science & Technology

1981-01-01

sites in the ocean will be executed by EPA or CE and will be based on Environmental studies of each site, and on historical knowledge of the impact...3 The results of the-s’ studies will be used to prepare an E-A and in some cases an EIS. An important provision regarding the number of separate...assessment for all sites within a particular geographic area may be prepared based on complete disposal site designation or evaluation studies on a typical

Dredged Material Management Categories for Tracking Beneficial Use

DTIC Science & Technology

2015-06-01

beneficial use opportunities at the point of initial discharge will typically be more efficient rather than recycling previously placed dredged sediment...rehandling for landfill cover, mine reclamation, construction fill, etc.) 4. Upland Disposal: DM placed in an up-land CDF for disposal with no...intention of present or future beneficial purpose. This option includes rehandling for disposal into a landfill , but does not include reclamation uses

Social and Economic Impacts of Selected Potential Dredged Material Containment Facilities in Long Island Sound.

DTIC Science & Technology

1981-09-01

GRANT NuMBER(s) CENTER FOR THE ENVIRONMENT AND MAN, INC. DACW 33-8U-~e--’-e/ Work Order No. 8 I.~3 PERFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM ...08-735 Program Manager Lynn E. Johnson Principal Investigator Gaylord M. Northrop Project Staff John Ball Kenneth Bober Kayla Costenoble Brian...determination of the merits of continuing the program . This is a Stage 2 report. While six potential dredged material containment facilities are

Geotechnical engineering for ocean waste disposal. An introduction

USGS Publications Warehouse

Lee, Homa J.; Demars, Kenneth R.; Chaney, Ronald C.; ,

1990-01-01

As members of multidisciplinary teams, geotechnical engineers apply quantitative knowledge about the behavior of earth materials toward designing systems for disposing of wastes in the oceans and monitoring waste disposal sites. In dredge material disposal, geotechnical engineers assist in selecting disposal equipment, predict stable characteristics of dredge mounds, design mound caps, and predict erodibility of the material. In canister disposal, geotechnical engineers assist in specifying canister configurations, predict penetration depths into the seafloor, and predict and monitor canister performance following emplacement. With sewage outfalls, geotechnical engineers design foundation and anchor elements, estimate scour potential around the outfalls, and determine the stability of deposits made up of discharged material. With landfills, geotechnical engineers evaluate the stability and erodibility of margins and estimate settlement and cracking of the landfill mass. Geotechnical engineers also consider the influence that pollutants have on the engineering behavior of marine sediment and the extent to which changes in behavior affect the performance of structures founded on the sediment. In each of these roles, careful application of geotechnical engineering principles can contribute toward more efficient and environmentally safe waste disposal operations.

A technique for the assessment of the visual impact of nearshore confined dredged materials and other built islands

Treesearch

Roy Mann

1979-01-01

Drilling rigs, confined dredged material disposal sites power and sewage treatment facilities, and other built objects on or near shorelines have often created appreciable impacts on the aesthetic perceptions of residents and recreational users. Techniques for assessing such impacts that are reviewed in this paper include viewscape analysis for large-scale shore...

Draft Genome Sequence of Oil-Degrading Bacterium Gallaecimonas pentaromativorans Strain YA_1 from the Southwest Indian Ocean

PubMed Central

Xu, Yiyuan; Ren, Chong; Chen, Ruixuan

2016-01-01

Gallaecimonas pentaromativorans has been previously reported to be capable of degrading crude oil and diesel oil. G. pentaromativorans strain YA_1 was isolated from the southwest Indian Ocean and can degrade crude oil. This study reports the draft genome sequence of G. pentaromativorans, which can provide insights into the mechanisms of microbial oil biodegradation. PMID:27491993

Acoustic mapping of the regional seafloor geology in and around Hawaiian ocean dredged-material disposal sites

USGS Publications Warehouse

Torresan, Michael E.; Gardner, James V.

2000-01-01

During January and February 1998 the U.S. Geological Survey Coastal and Marine Geology Team (USGS) conducted regional high-resolution multibeam mapping surveys of the area surrounding EPA-designated ocean disposal sites located offshore of the Hawaiian Islands of Oahu, Kauai, Maui, and Hawaii. The sites are all located within 5 nautical miles of shore on insular shelves or slopes. Regional maps were required of areas much larger than the disposal sites themselves to assess both the regional seafloor geology and the immediate vicinity of the disposal sites. The purpose of the disposal site surveys was to delimit the extent of disposal material by producing detailed bathymetric and backscatter maps of the seafloor with a ± 1 m spatial accuracy and <1% depth error. The advantage of using multibeam over conventional towed, single-beam sidescan sonar is that the multibeam data are accurately georeferenced for precise location of all imaged features. The multibeam produces a coregistered acoustic-backscatter map that is often required to locate individual disposal deposits. These data were collected by the USGS as part of its regional seafloor mapping and in support of ocean disposal site monitoring studies conducted in cooperation with the US Environmental Protection Agency (EPA) and the US Army Corps of Engineers (COE).

Long-Term Management Strategy for Dredged Material Disposal for Naval Facilities at Pearl Harbor, Hawaii. Phase II - Evaulation of Alternatives

DTIC Science & Technology

2000-03-01

26 Leachate Pathway.................................... 31 Plant Uptake Pathway.................................. 35 Volatization and Odor...Bi13 Appendix C - Surface Runoff Testing............................Cl Appendix D - Leachate Evaluation..............................D1 Appendix E...Oxidized Dredged Material..........................29 Table 7. Mixing Zone Requirement for Runoff Discharges............ 30 Table 8. Leachate Quality

Trace elements in soil and biota in confined disposal facilities for dredged material

USGS Publications Warehouse

Beyer, W.N.; Miller, G.; Simmers, J.W.

1990-01-01

We studied the relation of trace element concentrations in soil to those in house mice (Mus musculus), common reed (Phragmites australis) and ladybugs (Coccinella septempunctata) at five disposal facilities for dredged material. The sites had a wide range of soil trace element concentrations, acid soils and a depauperate fauna. They were very poor wildlife habitat because they were dominated by the common reed. Bioassay earthworms exposed to surface soils from three of the five sites died, whereas those exposed to four of five soils collected a meter deep survived, presumably because the deeper, unoxidized soil, was not as acid. Concentrations of Ni and Cr in the biota from each of the sites did not seem to be related to the concentrations of the same elements in soil. Although Pb, Zn and Cu concentrations in biota were correlated with those in soil, the range of concentrations in the biota was quite small compared to that in soil. The concentrations of Pb detected in mice were about as high as the concentrations previously reported in control mice from other studies. Mice from the most contaminated site (530 ppm Pb in soil) contained only slightly more Pb (8 ppm dry wt) than did mice (2-6 ppm dry wt) from sites containing much less Pb (22-92 ppm in soil). Despite the acid soil conditions, very little Cd was incorporated into food chains. Rather, Cd was leaching from the surface soil. We concluded that even the relatively high concentrations of trace elements in the acid dredged material studied did not cause high, concentrations of trace elements in the biota.

Crustal Magnetization Model of Maud Rise in the Southwest Indian Ocean

NASA Technical Reports Server (NTRS)

Kim, Hyung Rae; vanFrese, Ralph R. B.; Golynsky, Alexander V.; Taylor, Patrick T.; Kim, Jeong Woo

2004-01-01

We modeled the crustal magnetization for the Maud Rise in the south-west Indian Ocean off the coast of East Antarctica using magnetic observations from the Oersted satellite and near-surface surveys complied by the Antarctic Digital Magnetic Anomaly Project (ADMAP). A new inversion modeling scheme of the multi-altitude anomaly fields suggests that the magnetic effects due to crustal thickness variations and remanence involving the normal polarity Cretaceous Quiet Zone (KQZ) become increasingly dominant with altitude. The magnetic crustal thickness effects were modeled in the Oersted data using crustal thickness variations derived from satellite altitude gravity data. Remanent magnetization modeling of the residual Oersted and near-surface magnetic anomalies supports extending the KQZ eastwards to the Astrid Ridge. The remaining near-surface anomalies involve crustal features with relatively high frequency effects that are strongly attenuated at satellite altitudes. The crustal modeling can be extended by the satellite magnetic anomalies across the Indian Ocean Ridge for insight on the crustal properties of the conjugate Agulhas Plateau. The modeling supports the Jurassic reconstruction of Gondwana when the African Limpopo-Zambezi and East Antarctic Princess Astrid coasts were connected as part of a relatively demagnetized crustal block.

Thermal Consolidation of Dredge Sand for Artificial Reef Formations

NASA Astrophysics Data System (ADS)

Trevino, Alexandro

Coral Reef ecosystems have degraded over years due to a variety of environmental issues such as ocean acidification. The continuous stress has detrimental effects on coral reef ecosystems that can possibly lead to the loss of the ecosystem. Our research aims to construct a prototype of an artificial reef by consolidating dredge sand from the ship channels of South Texas. Consolidation is achieved through an aluminum polytetrafluoroethylene self-propagating high temperature process that yields a solid formation to mimic the physical properties of coral reef structures. Using thermodynamic calculations, the variation of initial components was determined that reached an adiabatic temperature with a maximum peak of 2000 K. The self-sustaining reaction front was obtained to rigidly consolidate the dredge sand only at composition concentrations exceeding a critical value of 24 wt.% Al, and 3 wt.% PTFE. The combustion synthesis produced a consolidated formation with a hardened and porous structure.

PHYTOREMEDIATING DREDGED SEDIMENTS: A BENEFICIAL REUSE PROTOCOL

EPA Science Inventory

The Jones Island Confined Disposal Facility (CDF) located in Milwaukee Harbor Wisconsin, receives dredged materials from normal maintenance of Milwaukee's waterways. Like many CDFs they face the dilemma of steady inputs and no feasible alternative for expansion. The Army Corps of...

Polymorphic Microsatellite Loci for Endemic Mussismilia Corals (Anthozoa: Scleractinia) of the Southwest Atlantic Ocean.

PubMed

Zilberberg, Carla; Peluso, Lívia; Marques, Jessica A; Cunha, Haydée

2014-01-01

In the Southwest Atlantic, coral reefs are unique due to their growth form, low species richness, and a high level of endemic coral species, which include the most important reef builders. Although these reefs are the only true biogenic reefs in the South Atlantic Ocean, population genetic studies are still lacking. The purpose of this study was to develop a suite of microsatellite loci to help gain insights into the population diversity and connectivity of the endemic scleractinian coral with the largest distributional range along the Southwest Atlantic coast, Mussismilia hispida Fourteen microsatellite loci were characterized, and their degree of polymorphism was analyzed in 33 individuals. The number of alleles varied between 4 and 17 per loci, and H o varied between 0.156 and 0.928, with 2 loci showing significant heterozygote deficiency. Cross-amplification tests on the other 2 species of the genus (Mussismilia braziliensis and Mussismilia harttii) demonstrated that these markers are suitable for studies of population diversity and structure of all 3 species of Mussismilia Because they are the most important reef builders in the Southwest Atlantic, the developed microsatellite loci may be important tools for connectivity and conservation studies of these endemic corals. © The American Genetic Association 2014. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Fishery resource utilization of a restored estuarine borrow pit: a beneficial use of dredged material case study.

PubMed

Reine, Kevin; Clarke, Douglas; Ray, Gary; Dickerson, Charles

2013-08-15

Numerous pits in coastal waters are subject to degraded water quality and benthic habitat conditions, resulting in degraded fish habitat. A pit in Barnegat Bay, New Jersey (USA) was partially filled with dredged sediment to increase flushing, alleviate hypoxia, and enhance benthic assemblages. Restoration objectives were assessed in terms of benthic community parameters and fishery resource occupation. Restoration resulted in increased benthic diversity (bottom samples) and the absence of water column stratification. Fisheries resources occupied the entire water column, unlike pre-restoration conditions where finfish tended to avoid the lower water column. The partial restoration option effectively reproduced an existing borrow pit configuration (Hole #5, control), by decreasing total depth from -11 m to -5.5 m, thereby creating a habitat less susceptible to hypoxic/anoxic conditions, while retaining sufficient vertical relief to maintain associations with juvenile weakfish and other forage fishes. Partially filling pits using dredged material represents a viable restoration alternative. Published by Elsevier Ltd.

Thin Layer Placement of Dredged Material on Coastal Wetlands: A Review of the Technical and Scientific Literature

DTIC Science & Technology

2007-12-01

the United States in wetland loss, losing as much as 24 square miles each year (Louisiana Department of Natural Resources 2007). Extreme events such...Studies of the effects of placing dredged materials on marshes originated with recognition that marshes are adapted to respond to natural processes...23, 30, 61, and 91 cm) on replicated plots of natural , undisturbed marshes in Glynn County, Georgia. While this study was intended to test an

Initial Development of Riparian and Marsh Vegetation on Dredged-material Islands in the Sacramento-San Joaquin River Delta, California

Treesearch

A. Sidney England; Mark K. Sogge; Roy A. Woodward

1989-01-01

Natural vegetation establishment and development were monitored for 3 1/2 years on a new, dredged-material island located within the breached levees at Donlon Island in the Sacramento-San Joaquin River Delta. Vegetation measurements and maps prepared annually indicate that marsh and riparian vegetation types have developed rapidly. Topographic data for the island has...

Dredged sediments as a resource for brick production: Possibilities and barriers from a consumers’ perspective

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cappuyns, Valérie, E-mail: valerie.cappuyns@kuleuven.be; Deweirt, Valentine; Rousseau, Sandra

Highlights: • Consumers are suspicious towards bricks produced from dredged sediments. • Technical quality, safety and environmental impacts are considered key characteristics. • Public has insufficient knowledge on bricks produced from dredged sediments. • Sensitization and provision of information to customers are of primary importance. - Abstract: A possible solution for the oversupply of dredged sediments is their use as a raw material in brick production. Despite the fact that several examples (e.g., Agostini et al., 2007; Hamer and Karius, 2002; Xu et al., 2014) show that this application is feasible, some economic, technical and social limitations interfere with themore » development of a market of dredged materials in brick production in Flanders. While we describe the main characteristics of the supply side, we focus on the limitations and barriers from the demand side in the present study. Based on a consumers survey we analyze consumers’ risk perceptions and attitudes towards bricks produced from dredged sediments. Consumers in Flanders are rather suspicious with respect to bricks produced from dredged sediments and their risk perception is mainly determined by the possibility of a bad bargain (brick of inferior quality) and the connotation with chemical contamination. The willingness to pay for bricks made from dredged sediments is mainly influenced by the age of the respondents, as well environmental awareness, and the respondents’ belief in their ability to influence environmental problems. Sensitization and information of customers seems to be of primary importance to make dredged-sediment-derived bricks a successful product.« less

Effects of suction dredging on streams: a review and an evaluation strategy

Treesearch

Bret C. Harvey; Thomas E. Lisle

1998-01-01

Abstract - Suction dredging for gold in river channels is a small-scale mining practice whereby streambed material is sucked up a pipe, passed over a sluice box to sort out the gold, and discarded as tailings over another area of bed. Natural resource managers should be concerned about suction dredging because it is common in streams in western North America that...

Reports of Public Scoping Meetings for the Supplemental Environmental Impact Statement for the Designation of Dredged Material Disposal Sites in Eastern Long Island Sound

EPA Pesticide Factsheets

These reports provide summaries of the scoping meetings as part of the Supplemental Environmental Impact Statement (SEIS) process for the designation of dredged material disposal sites in Eastern Long Island Sound.

15 CFR Appendix D to Subpart M of... - Dredged Material Disposal Sites Adjacent to the Monterey Bay National Marine Sanctuary

Code of Federal Regulations, 2011 CFR

2011-01-01

... Adjacent to the Monterey Bay National Marine Sanctuary D Appendix D to Subpart M of Part 922 Commerce and... SANCTUARY PROGRAM REGULATIONS Monterey Bay National Marine Sanctuary Pt. 922, Subpt. M, App. D Appendix D to Subpart M of Part 922—Dredged Material Disposal Sites Adjacent to the Monterey Bay National Marine...

Dredging and contaminant exposure to tree swallows nesting on the upper Mississippi River

USGS Publications Warehouse

Custer, Thomas W.; Dummer, Paul; Custer, Christine M.; Warburton, David

2013-01-01

n 2008 and 2009, dredge material from the Mississippi River in Pool 8 south of Brownsville, Minnesota was used to construct nearby islands. Chemical analysis of sediment in 2001 and 2002 in the area to be dredged indicated detectable concentrations of organic and inorganic contaminants. Tree swallows (Tachycineta bicolor), whose diet is mainly aquatic invertebrates, were used to evaluate contaminant exposure in both the dredged and newly created habitat. Organic and inorganic contaminant data were collected from tree swallows in 2007 through 2010 at one study site near the dredging operation, a reference study site upriver from the dredging activity, one study site down river from the dredging activity, and one study site on a newly created island (2009 and 2010 only). Organic and element concentrations were at background levels in all samples. Polychlorinated biphenyl and p,p′-dichlorodiphenyldichloroethylene concentrations in tree swallow nestlings decreased at all study sites over the period 2007 to 2010 including the island study site between 2009 and 2010. Element concentrations in tree swallow livers for the non-island study sites did not show a trend among years in relation to the dredging. Selenium concentrations at the newly created island were higher and cadmium concentrations were lower in 2010 than 2009. Hatching success of eggs in successful nests was not associated with dredging activities.

Literature Review of Dredging Physical Models

DTIC Science & Technology

This U.S. Army Engineer Research and Development Center, Coastal and Hydraulics Laboratory, special report presents a review of dredging physical...one-third of the dredging performed by the U.S. Army Corps of Engineers is done by hopper dredges with dragheads. Identified research gaps include

Improving Site Characterization for Rock Dredging using a Drilling Parameter Recorder and the Point Load Test

DTIC Science & Technology

1994-09-01

materials. Also, available data from drilling rates in the mining and tunneling industries (Howarth and Rowlands 1987, Somerton 1959) indicate a...selected uniform natural rock materials and several man -made rock simulants were used to obtain drilling parameter records for materials of known...Dredging Seminar, Atlantic City, NJ, May 1993. Western Dredging Association (WEDA) and Texas A&M University. Somerton , W. H. (1959). "A laboratory study of

New Bedford Harbor Superfund Project, Acushnet River Estuary Engineering Feasibility Study of Dredging and Dredged Material Disposal Alternatives. Report 9. Laboratory-Scale Application of Solidification/Stabilization Technology

DTIC Science & Technology

1989-01-01

force) per square inch to kilopascals, multiply by 6.894757. ** Flue - gas desulfurization . 27 1.0 sediment process, UCS measurements for solidified...Dredging Control Technoloqies 11 Evaluation of Conceptual Dredging and Disposal Alternatives 12 Executive Summary Destroy this report when no longer needed...solubility of metals by controlling the pH and alkalinity. Additional metal immobilization can be obtained by modify- ing the process to include

Environmental dredging residual generation and management.

PubMed

Patmont, Clay; LaRosa, Paul; Narayanan, Raghav; Forrest, Casey

2018-05-01

The presence and magnitude of sediment contamination remaining in a completed dredge area can often dictate the success of an environmental dredging project. The need to better understand and manage this remaining contamination, referred to as "postdredging residuals," has increasingly been recognized by practitioners and investigators. Based on recent dredging projects with robust characterization programs, it is now understood that the residual contamination layer in the postdredging sediment comprises a mixture of contaminated sediments that originate from throughout the dredge cut. This mixture of contaminated sediments initially exhibits fluid mud properties that can contribute to sediment transport and contamination risk outside of the dredge area. This article reviews robust dredging residual evaluations recently performed in the United States and Canada, including the Hudson River, Lower Fox River, Ashtabula River, and Esquimalt Harbour, along with other projects. These data better inform the understanding of residuals generation, leading to improved models of dredging residual formation to inform remedy evaluation, selection, design, and implementation. Data from these projects confirm that the magnitude of dredging residuals is largely determined by site conditions, primarily in situ sediment fluidity or liquidity as measured by dry bulk density. While the generation of dredging residuals cannot be avoided, residuals can be successfully and efficiently managed through careful development and implementation of site-specific management plans. Integr Environ Assess Manag 2018;14:335-343. © 2018 The Authors. Integrated Environmental Assessment and Management Published by Wiley Periodicals, Inc. on behalf of Society of Environmental Toxicology & Chemistry (SETAC). © 2018 The Authors. Integrated Environmental Assessment and Management Published by Wiley Periodicals, Inc. on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

A Physical Model for Extreme Drought over Southwest Asia

NASA Astrophysics Data System (ADS)

Hoell, A.; Barlow, M. A.; Funk, C. C.; Cannon, F.

2015-12-01

The socioeconomic difficulties of Southwest Asia, defined as the area bound by the domain 25°N-40°N and 40°E-70°E, which includes the countries of Iran, Afghanistan and Pakistan, are exacerbated by extreme precipitation deficits during the November-April rainy season. The precipitation deficits during many Southwest Asia droughts have been examined in terms of the forcing by climate variability originating over the Pacific Ocean as a result of the El Niño-Southern Oscillation (ENSO), Pacific Decadal Variability (PDV) and the long-term warming of Pacific (LT) sea surface temperatures (SST). Here, we 1) examine how the most extreme November-April Southwest Asia droughts relate to global SSTs and the associated large-scale atmospheric circulation anomalies, 2) analyze the specific atmospheric forcing mechanisms responsible for changes in regional Southwest Asian precipitation and 3) examine the causal mechanisms responsible for the increased frequency of Southwest Asia drought in recent decades. The driest November-April seasons during 1948-2012 over Southwest Asia are forced by subsidence and reductions of moisture fluxes as a result of the interaction of the mean flow with anomalous zonally-symmetric high pressure throughout the Northern Hemisphere. The anomalous zonally-symmetric high pressure throughout the Northern Hemisphere occurs simultaneously with cool central and eastern Pacific SST anomalies associated with La Niña and the negative phase of PDV and a warm west Pacific Ocean caused in part by the long-term warming of the west Pacific Ocean. The long-term warming of the Pacific Ocean has driven the regional precipitation declines in recent decades, with the strongest signal occurring over areas bordering the Arabian Sea.

Low frequency baleen whale calls detected on ocean-bottom seismometers in the Lau basin, southwest Pacific Ocean.

PubMed

Brodie, Dana C; Dunn, Robert A

2015-01-01

Ten months of broadband seismic data, recorded on six ocean-bottom seismographs located in the Lau Basin, were examined to identify baleen whale species. As the first systematic survey of baleen whales in this part of the southwest Pacific Ocean, this study reveals the variety of species present and their temporal occurrence in and near the basin. Baleen whales produce species-specific low frequency calls that can be identified by distinct patterns in data spectrograms. By matching spectrograms with published accounts, fin, Bryde's, Antarctic blue, and New Zealand blue whale calls were identified. Probable whale sounds that could not be matched to published spectrograms, as well as non-biologic sounds that are likely of volcanogenic origin, were also recorded. Detections of fin whale calls (mid-June to mid-October) and blue whale calls (June through September) suggest that these species migrate through the region seasonally. Detections of Bryde's whale calls (primarily February to June, but also other times of the year) suggest this species resides around the basin nearly year round. The discovery of previously unpublished call types emphasizes the limited knowledge of the full call repertoires of baleen whales and the utility of using seismic survey data to enhance understanding in understudied regions.

Deep-tow magnetic survey above large exhumed mantle domains of the eastern Southwest Indian ridge

NASA Astrophysics Data System (ADS)

Bronner, A.; Munschy, M.; Carlut, J. H.; Searle, R. C.; Sauter, D.; Cannat, M.

2011-12-01

The recent discovery of a new type of seafloor, the "smooth seafloor", formed with no or very little volcanic activity along the ultra-slow spreading Southwest Indian ridge (SWIR) shows an unexpected complexity in processes of generation of the oceanic lithosphere. There, detachment faulting is thought to be a mechanism for efficient exhumation of deep-seated mantle rocks. We present here a deep-tow geological-geophysical survey over smooth seafloor at the eastern SWIR (62-64°N) combining magnetic data, geology mapping from side-scan sonar images and results from dredge sampling. We introduce a new type of calibration approach for deep-tow fluxgate magnetometer. We show that magnetic data can be corrected from the magnetic effect of the vehicle with no recourse to its attitude (pitch, roll and heading) but only using the 3 components recorded by the magnetometer and an approximation of the scalar intensity of the Earth magnetic field. The collected dredge samples as well as the side-scan images confirm the presence of large areas of exhumed mantle-derived peridodites surrounded by a few volcanic constructions. This allows us to hypothesis that magnetic anomalies are caused by serpentinized peridotites or magmatic intrusions. We show that the magnetic signature of the smooth seafloor is clearly weaker than the surrounding volcanic areas. Moreover, the calculated magnetization of a source layer as well as the comparison between deep-tow and sea-surface magnetic data argue for strong East-West variability in the distribution of the magnetized sources. This variability may results from fluid-rocks interaction along the detachment faults as well as from the repartition of the volcanic material and thus questions the seafloor spreading origin of the corresponding magnetic anomalies. Finally, we provide magnetic arguments, as calculation of block rotation or spreading asymmetry in order to better constrain tectonic mechanisms that occur during the formation of this

Comparison of the basin-scale effect of dredging operations and natural estuarine processes on suspended sediment concentration

USGS Publications Warehouse

Schoellhamer, D.H.

2002-01-01

Suspended sediment concentration (SSC) data from San Pablo Bay, California, were analyzed to compare the basin-scale effect of dredging and disposal of dredged material (dredging operations) and natural estuarine processes. The analysis used twelve 3-wk to 5-wk periods of mid-depth and near-bottom SSC data collected at Point San Pablo every 15 min from 1993-1998. Point San Pablo is within a tidal excursion of a dredged-material disposal site. The SSC data were compared to dredging volume, Julian day, and hydrodynamic and meteorological variables that could affect SSC. Kendall's ??, Spearman's ??, and weighted (by the fraction of valid data in each period) Spearman's ??w correlation coefficients of the variables indicated which variables were significantly correlated with SSC. Wind-wave resuspension had the greatest effect on SSC. Median water-surface elevation was the primary factor affecting mid-depth SSC. Greater depths inhibit wind-wave resuspension of bottom sediment and indicate greater influence of less turbid water from down estuary. Seasonal variability in the supply of erodible sediment is the primary factor affecting near-bottom SSC. Natural physical processes in San Pablo Bay are more areally extensive, of equal or longer duration, and as frequent as dredging operations (when occurring), and they affect SSC at the tidal time scale. Natural processes control SSC at Point San Pablo even when dredging operations are occurring.

Preliminary Assessment of Potential Impacts to Dungeness Crabs from Disposal of Dredged Materials from the Columbia River

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pearson, Walter H.; Miller, Martin C.; Williams, Greg D.

2006-02-01

Dredging of the Columbia River navigation channel has raised concerns about dredging-related impacts on Dungeness crabs (Cancer magister). The overall objectives of this effort are to synthesize what is known about disposal effects on Dungeness crabs (Phase 1) and to offer approaches to quantify the effects, including approaches to gain a population-level perspective on any effects found in subsequent studies (Phase 2). This report documents Phase 1, which included (1) development of a conceptual model to integrate knowledge about crab biology and the physical processes occurring during disposal, (2) application of physics-based numerical modeling of the disposal event to understandmore » the physical forces and processes to which a crab might be exposed during disposal, (3) conduct of a vulnerability analysis to identify the potential mechanisms by which crabs may be injured, and (4) recommendations of topics and approaches for future studies to assess the potential population-level effects of disposal on Dungeness crabs. The conceptual model first recognizes that disposal of dredged materials is a physically dynamic process with three aspects: (1) convective descent and bottom encounter, (2) dynamic collapse and spreading, and (3) mounding. Numerical modeling was used to assess the magnitude of the potentially relevant forces and extent of mounding in single disposal events. The modeling outcomes show that predicted impact pressure, shear stress, and mound depth are greatly reduced by discharge in deep water, and somewhat reduced at longer discharge duration. The analysis of numerical modeling results and vulnerabilities indicate that the vulnerability of crabs to compression forces under any of the disposal scenarios is low. For the deep-water disposal scenarios, the maximum forces and mounding do not appear to be sufficiently high enough to warrant concern for surge currents or burial at the depths involved (over 230 ft). For the shallow-water (45 to 65 ft

Overdepth Dredging and Characterization Depth Recommendations

DTIC Science & Technology

2007-06-01

bucket is hoisted to the surface and usually side dumped into a barge or sidecast to its placement site. The general clamshell dredge’s horizontal...excavation accuracies vary as a function of type of dredging equipment used (mechanical or hydraulic ) and interaction with site-specific physical...surveys. Dredge excavation accuracies vary as a function of the type of dredging equipment used (mechanical or hydraulic ) and its respective

Solidification/stabilization of dredged marine sediments for road construction.

PubMed

Wang, Dong Xing; Abriak, Nor Edine; Zentar, Rachid; Xu, WeiYa

2012-01-01

Cement/lime-based solidification is an environmentally sound solution for the management of dredged marine sediments, instead of traditional solutions such as immersion. Based on the mineralogical composition and physical characteristics of Dunkirk sediments, the effects of cement and lime are assessed through Atterberg limits, modified Proctor compaction, unconfined compressive strength and indirect tensile strength tests. The variation of Atterberg limits and the improvement in strength are discussed at different binder contents. The potential of sediments solidified with cement or lime for road construction is evaluated through a proposed methodology from two aspects: I-CBR value and material classification. The test results show the feasibility of solidified dredged sediments for beneficial use as a material in road construction. Cement is superior to lime in terms of strength improvement, and adding 6% cement is an economic and reasonable method to stabilize fine sediments.

Lightweight Aggregate Made from Dredged Material in Green Roof Construction for Stormwater Management.

PubMed

Liu, Rui; Coffman, Reid

2016-07-23

More than 1.15 million cubic meters (1.5 million cubic yards) of sediment require annual removal from harbors and ports along Ohio's Lake Erie coast. Disposing of these materials into landfills depletes land resources, while open water placement of these materials deteriorates water quality. There are more than 14,000 acres of revitalizing brownfields in Cleveland, U.S., many containing up to 90% impervious surface, which does not allow "infiltration" based stormwater practices required by contemporary site-based stormwater regulation. This study investigates the potential of sintering the dredged material from the Harbor of Cleveland in Lake Erie to produce lightweight aggregate (LWA), and apply the LWA to green roof construction. Chemical and thermal analyses revealed the sintered material can serve for LWA production when preheated at 550 °C and sintered at a higher temperature. Through dewatering, drying, sieving, pellet making, preheating, and sintering with varying temperatures (900-1100 °C), LWAs with porous microstructures are produced with specific gravities ranging from 1.46 to 1.74, and water absorption capacities ranging from 11% to 23%. The water absorption capacity of the aggregate decreases as sintering temperature increases. The LWA was incorporated into the growing media of a green roof plot, which has higher water retention capacity than the conventional green roof system.

Effect of dredge spoil deposition on fecal coliform counts in sediments at a disposal site.

PubMed Central

Babinchak, J A; Graikoski, J T; Dudley, S; Nitkowski, M F

1977-01-01

The most-probable-number of fecal coliforms in sediments was monitored at the New London dump site in Long Island Sound during the deposition of dredge spoil from the Thames River. Although the geometric mean for fecal coliforms at five stations in the river was 14,000/100 ml before dredging commenced, the deposition of this material did not increase the incidence of fecal coliforms at 17 spoil stations and 13 control stations in the disposal and surrounding areas. Fecal coliforms appear to occur only in the surface sediment material and are diluted by the subsurface material during the dredging operation. Fecal coliform analyses of bottom waters during high and low tides indicated that the flow of water from the Thames River played a major role in determining the most-probable-number of fecal coliforms in the sediments at the disposal site. PMID:329761

Role of the Southwest Tropical Indian Ocean on the Modulation of Tropical Cyclones

NASA Astrophysics Data System (ADS)

Burns, J. M.; Bulusu, S.

2016-02-01

The Seychelles-Chagos Thermocline Ridge (SCTR), located in the Indian Ocean and bound by 55°E-65°E and 5°S-12°S, is a key region for air-sea interaction. This feature inhabits one of the seven ocean basins where tropical cyclones regularly form and is unique in that the variability of the subsurface can influence cyclogenesis. Tropical cyclone days for this region span from November through April, with peaks in the months of January and February. The influence of thermocline variation is particularly strong during the months of December through May and it is known that a high correlation exists between the depth of the thermocline and sea surface temperature (key ingredient for cyclogenesis). Past research provides evidence that more tropical cyclone days are observed in Southwest Tropical Indian Ocean (SWTIO) during austral summers with a deep thermocline ridge than in austral summers when a shallow thermocline ridge exists. The formation and thickness of the Barrier layer (BL) have also been shown to impact tropical cyclones in this region. BL formation is an important parameter for surface heat exchange. The amount of salt in the boundary layer may also effect heat exchange and thus cyclones. Other ocean basins have verified that salt-stratified barrier layers influence the intensification of tropical cyclones, however, the role that salinity in SWTIO plays in the modulation of tropical cycles has still yet to be explored. This study further explores how the dynamic properties of the SCTR influence the modulation of cyclones. Primarily Argo observations of salinity and temperature along with Soil Moisture Ocean Salinity (SMOS) and Aquarius salinity, and Hybrid Coordinate Ocean Model (HYCOM) simulations are used to examine this influence of the BL and salinity on cyclone formation and intensity in this region. This study is progressed with a particular focus on the austral summer of 2012/2013 when seven tropical cyclones developed in the region.

Sediment Engineering thru Dredging and with Nature (SETDWN) - Fate of Fines in the Dredging and Placement Process

DTIC Science & Technology

2015-05-15

operations and beach construction perspective, material is lost and a significant percent of fines is winnowed during the dredging and placement...discharged at the beach weather it is from a hopper pumpout, cuttersuction, or hydraulic offloader; experiences similar winnowing processes. The beach...of compliance with in situ percent fines criteria. This same process can be employed for the winnowing of other constituents in mixed sediments as

Characterization of metals released from coal fly ash during dredging at the Kingston ash recovery project.

PubMed

Bednar, A J; Averett, D E; Seiter, J M; Lafferty, B; Jones, W T; Hayes, C A; Chappell, M A; Clarke, J U; Steevens, J A

2013-09-01

A storage-pond dike failure occurred on December 22, 2008 at the Tennessee Valley Authority Kingston Fossil Plant resulting in the release of over 4million cubic meters (5million cubic yards) of fly ash. Approximately half of the released ash was deposited in the main channel of the Emory River, Tennessee, USA. Remediation efforts of the Emory River focused on hydraulic dredging, as well as mechanical excavation in targeted areas. However, agitation of the submerged fly ash during hydraulic dredging introduces river water into the fly ash material, which could promote dissolution and desorption of metals from the solid fly ash material. Furthermore, aeration of the dredge slurry could alter the redox state of metals in the fly ash material and thereby change their sorption, mobility, and toxicity properties. The research presented here focuses on the concentrations and speciation of metals during the fly ash recovery from the Emory River. Our results indicate that arsenite [As(III)] released from the fly ash material during dredging was slowly oxidized to arsenate [As(V)] in the slurry recovery system with subsequent removal through precipitation or sorption reactions with suspended fly ash material. Concentrations of other dissolved metals, including iron and manganese, also generally decreased in the ash recovery system prior to water discharge back to the river. Published by Elsevier Ltd.

A Multifactor Ecosystem Assessment of Wetlands Created Using a Novel Dredged Material Placement Technique in the Atchafalaya River, Louisiana: An Engineering With Nature Demonstration Project

DTIC Science & Technology

functions. The strategic placement of dredged materials in locations that mimic natural process promoted additional ecological benefits, especially...regarding wading bird and infaunal habitat, thus adhering to Engineering With Nature (EWN) processes. The multifactor approach improved the wetland

Methods To Characterize Contaminant Residuals After Environmental Dredging

EPA Science Inventory

Environmental dredging is a common remedial action for managing contaminated sediments. However, post dredging contaminant concentrations in surface sediment are difficult to predict prior to initiating dredging actions. In some cases, post surface concentrations have been high...

WODA Technical Guidance on Underwater Sound from Dredging.

PubMed

Thomsen, Frank; Borsani, Fabrizio; Clarke, Douglas; de Jong, Christ; de Wit, Pim; Goethals, Fredrik; Holtkamp, Martine; Martin, Elena San; Spadaro, Philip; van Raalte, Gerard; Victor, George Yesu Vedha; Jensen, Anders

2016-01-01

The World Organization of Dredging Associations (WODA) has identified underwater sound as an environmental issue that needs further consideration. A WODA Expert Group on Underwater Sound (WEGUS) prepared a guidance paper in 2013 on dredging sound, including a summary of potential impacts on aquatic biota and advice on underwater sound monitoring procedures. The paper follows a risk-based approach and provides guidance for standardization of acoustic terminology and methods for data collection and analysis. Furthermore, the literature on dredging-related sounds and the effects of dredging sounds on marine life is surveyed and guidance on the management of dredging-related sound risks is provided.

Ecological evaluation of proposed dredged material from Richmond Harbor Deepening Project and the intensive study of the Turning Basin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pinza, M.R.; Mayhew, H.L.; Karle, L.M.

Richmond Harbor is on the eastern shoreline of central San Francisco Bay and its access channels and several of the shipping berths are no longer wide or deep enough to accommodate modem deeper-draft vessels. The Water Resources Development Act of 1986 (PL99-662) authorized the US Army Corps of Engineers (USACE), San Francisco District to deepen and widen the navigation channels in Richmond Harbor. Several options for disposal of the material from this dredging project are under consideration by USACE: disposal within San Francisco Bay, at open-ocean disposal sites, or at uplands disposal sites. Purpose of this study was to conductmore » comprehensive evaluations, including chemical, biological, and bioaccumulation testing of sediments in selected areas of Richmond Harbor. This information was required by the Environmental Protection Agency (EPA) and USACE. Battelle/Marine Sciences Laboratory collected 20 core samples, both 4-in. and 12-in., to a project depth of -40 ft mean lower low water (MLLW) (-38 ft MLLW plus 2 ft of overdepth) using a vibratory-hammer core. These 20 field samples were combined to form five test composites plus an older bay mud (OBM) composite that were analyzed for physical/chemical parameters, biological toxicity, and tissue chemistry. Solid-phase tests were conducted with the amphipod, Rhepoxynius abronius; the clam, Macoma nasuta; and the polychaete worm, Nephtys caecoides. Suspended-particulate-phase (SPP) tests were conducted with the sanddab, Citharichthys stigmaeus; the mysid, Holmesimysis costata; and the bivalve, Mytilus galloprovincialis. Bioaccumulation of contaminants was measured in tissues of Macoma nasuta and Nereis virens. Sediments from one ocean reference sediment, and two in-bay reference sediments, were tested concurrently. Results from analysis of the five test treatments were statistically compared with the reference sediment R-OS in the first five sections of this report.« less

Chemical characterisation of dredged sediments in relation to their potential use in civil engineering.

PubMed

Zuliani, Tea; Mladenovič, Ana; Ščančar, Janez; Milačič, Radmila

2016-04-01

During capital and/or maintenance dredging operations, large amounts of material are produced. Instead of their discharge, dredged sediments may be a valuable natural resource if not contaminated. One of the possible areas of application is civil engineering. In the present work, the environmental status of seaport dredged sediment was evaluated in order to investigate its potential applicability as a secondary raw material. Sediments were analysed for element concentrations in digested samples, aqueous extracts and fractions from sequential extraction; for fluoride, chloride and sulphate concentrations in aqueous extracts; and for tributyltin (TBT). Granulometric and mineralogical compositions were also analysed. The elemental impact was evaluated by calculation of the enrichment factors. The total element concentrations determined showed moderate contamination of the dredged sediments as was confirmed also by their moderate enrichment factors, presumably as a result of industrial and port activities. Elemental concentrations in the aqueous extract were very low and therefore do not represent any hazard for the environment. The water-soluble element concentrations were under the threshold levels set by the EU Directive on the landfill of waste, on the basis of which the applicability of dredged sediments in civil engineering is evaluated, while the content of chloride and sulphate were above the threshold levels. It was found out that due to the large amounts of sediment available, civil engineering applications such as the construction of embankments and backfilling is the most beneficial recycling solution at present.

Lightweight Aggregate Made from Dredged Material in Green Roof Construction for Stormwater Management

PubMed Central

Liu, Rui; Coffman, Reid

2016-01-01

More than 1.15 million cubic meters (1.5 million cubic yards) of sediment require annual removal from harbors and ports along Ohio’s Lake Erie coast. Disposing of these materials into landfills depletes land resources, while open water placement of these materials deteriorates water quality. There are more than 14,000 acres of revitalizing brownfields in Cleveland, U.S., many containing up to 90% impervious surface, which does not allow “infiltration” based stormwater practices required by contemporary site-based stormwater regulation. This study investigates the potential of sintering the dredged material from the Harbor of Cleveland in Lake Erie to produce lightweight aggregate (LWA), and apply the LWA to green roof construction. Chemical and thermal analyses revealed the sintered material can serve for LWA production when preheated at 550 °C and sintered at a higher temperature. Through dewatering, drying, sieving, pellet making, preheating, and sintering with varying temperatures (900–1100 °C), LWAs with porous microstructures are produced with specific gravities ranging from 1.46 to 1.74, and water absorption capacities ranging from 11% to 23%. The water absorption capacity of the aggregate decreases as sintering temperature increases. The LWA was incorporated into the growing media of a green roof plot, which has higher water retention capacity than the conventional green roof system. PMID:28773734

Appearance and water quality of turbidity plumes produced by dredging in Tampa Bay, Florida

USGS Publications Warehouse

Goodwin, Carl R.; Michaelis, D.M.

1984-01-01

Turbidity plumes in Tampa Bay, Florida, produced during ship-channel dredging operations from February 1977 to August 1978, were monitored in order to document plume appearance and water quality, evaluate plume influence on the characteristics of Tampa Bay water, and provide a data base for comparison with other areas that have similar sediment, dredge, placement, containment, and tide conditions. The plumes investigated originated from the operation of one hopper dredge and three cutterhead-pipeline dredges. Composition of bottom sediment was found to vary from 85 percent sand and shell fragments to 60 percent silt and clay. Placement methods for dredged sediment included beach nourishment, stationary submerged discharge, oscillating surface discharge, and construction of emergent dikes. Tidal currents ranged from slack water to flow velocities of 0.60 meter per second. Plumes were monitored simultaneously by (1) oblique and vertical 35-millimeter aerial photography and (2) water-quality sampling to determine water clarity and concentrations of nutrients, metals, pesticides, and industrial compounds. Forty-nine photographs depict plumes ranging in length from a few tens of meters to several kilometers and ranging in turbidity level from <10 to 200,000 nephelometric turbidity units. The most visible turbidity plumes were produced by surface discharge of material with high sand content into unconfined placement areas during times of strong tidal currents. The least visible turbidity plumes were produced by discharge of material with high silt and clay content into areas enclosed by floating turbidity barriers during times of weak tidal currents. Beach nourishment from hopper-dredge unloading operations also produced plumes of low visibility. Primary turbidity plumes were produced directly by dredging and placement operations; secondary plumes were produced indirectly by resuspension of previously deposited material. Secondary plumes were formed both by erosion, in

Evaluation and Development of Navigation Positioning and Monitoring Protocols for Dredged Material Disposal in Puget Sound.

DTIC Science & Technology

1986-02-01

Orlando. FL 3000 (305)281-S000 3S00( 6 ) eodmeter. Inc. Geodimeter 14-A 6000 t(S mm # 3 ppm) 511.300 Novato, CA 8000 (41S)677.12S6 15000 Ghodimeter 112...1.2 2.2 3.0 1 t(5mm + 5 ppm) t2" $19.950 Novato. CA 1.8 3.0 4.0 3 (415)883-2367 2.4 3.8 5.5 6 3.6 4.8 6.0 8 i-r Instrumnts EI/DM503 Automatic 1.5 2.5...POSITIONING LIMITATIONS FOR DREDGED MATERIAL DISPOSAL 4 BARGE MANEUVERABILITY 4 LIMITATIONS OF POSITIONING METHODS 5 Accuracy and Error 6 Site-Related

Criteria for the Depths of Dredged Navigational Channels.

DTIC Science & Technology

1983-05-01

can be controlled wLthin 5 ft to 10 ft. Otner fixed-spud plants are grab dredges and dipper dredges. They differ from the cutter suction dredge in...planned on a river mouth or a beach where a big amount of littoral drift is expected, the degree of maintenance dredging required in the future should be...paper presents a relatively simple method which permits a quick estimate of the siltation to be expected witnout the use of a big computer. This method

Integrating field research, modeling and remote sensing to quantify morphodynamics in a high-energy coastal setting, ocean beach, San Francisco, California

USGS Publications Warehouse

Barnard, P.L.; Hanes, D.M.

2006-01-01

Wave and coastal circulation modeling are combined with multibeam bathymetry, high-resolution beach surveys, cross-shore Personal Water Craft surveys, digital bed sediment camera surveys, and real-time video monitoring to quantify morphological change and nearshore processes at Ocean Beach, San Francisco. Initial SWAN (Simulating Waves Nearshore) wave modeling results show a focusing of wave energy at the location of an erosion hot spot on the southern end of Ocean Beach during prevailing northwest swell conditions. During El Nin??o winters, swell out of the west and southwest dominates the region, and although the wave energy is focused further to the north on Ocean Beach, the oblique wave approach sets up a strong northerly littoral drift, thereby starving the southern end of sediment, leaving it increasingly vulnerable to wave attack when the persistent northwest swell returns. An accurate assessment of the interaction between wave and tidal processes is crucial for evaluating coastal management options in an area that includes the annual dredging and disposal of ship channel sediment and an erosion hot spot that is posing a threat to local infrastructure. Copyright ASCE 2006.

The response of the southwest Western Australian wave climate to Indian Ocean climate variability

NASA Astrophysics Data System (ADS)

Wandres, Moritz; Pattiaratchi, Charitha; Hetzel, Yasha; Wijeratne, E. M. S.

2018-03-01

Knowledge of regional wave climates is critical for coastal planning, management, and protection. In order to develop a regional wave climate, it is important to understand the atmospheric systems responsible for wave generation. This study examines the variability of the southwest Western Australian (SWWA) shelf and nearshore wind wave climate and its relationship to southern hemisphere climate variability represented by various atmospheric indices: the southern oscillation index (SOI), the Southern Annular Mode (SAM), the Indian Ocean Dipole Mode Index (DMI), the Indian Ocean Subtropical Dipole (IOSD), the latitudinal position of the subtropical high-pressure ridge (STRP), and the corresponding intensity of the subtropical ridge (STRI). A 21-year wave hindcast (1994-2014) of the SWWA continental shelf was created using the third generation wave model Simulating WAves Nearshore (SWAN), to analyse the seasonal and inter-annual wave climate variability and its relationship to the atmospheric regime. Strong relationships between wave heights and the STRP and the STRI, a moderate correlation between the wave climate and the SAM, and no significant correlation between SOI, DMI, and IOSD and the wave climate were found. Strong spatial, seasonal, and inter-annual variability, as well as seasonal longer-term trends in the mean wave climate were studied and linked to the latitudinal changes in the subtropical high-pressure ridge and the Southern Ocean storm belt. As the Southern Ocean storm belt and the subtropical high-pressure ridge shifted southward (northward) wave heights on the SWWA shelf region decreased (increased). The wave height anomalies appear to be driven by the same atmospheric conditions that influence rainfall variability in SWWA.

PHYTOREMEDIATION OF DREDGED SEDIMENTS: A CASE STUDY AT THE JONES ISLAND CDF

EPA Science Inventory

The Jones Island Confined Disposal Facility (CDF) is a 44 acre in-lake area that receives dredged material from Milwaukee Harbor and the surrounding waterways. Some of those materials are contaminated with industrial waste and urban run-off. The CDF is nearing the end of its desi...

A physical model for extreme drought over southwest Asia: Chapter 17

USGS Publications Warehouse

Hoell, Andrew; Funk, Chris; Barlow, Mathew; Cannon, Forrest

2017-01-01

The socioeconomic difficulties of southwest Asia, defined as the area bound by the domain 25°N–40°N and 40°E–70°E, are exacerbated by extreme precipitation deficits during the November–April rainy season. The precipitation deficits during many southwest Asia droughts have been examined in terms of the forcing by climate variability originating over the Pacific Ocean as a result of the El Niño–Southern Oscillation (ENSO), Pacific decadal variability (PDV), and the long-term warming of Pacific (LT) sea surface temperatures (SST). Here we examine how the most extreme November–April southwest Asia droughts relate to global SSTs and the associated large-scale atmospheric circulation anomalies and analyze the specific atmospheric forcing mechanisms responsible for changes in regional southwest Asian precipitation. The driest November–April seasons during 1948–2012 over southwest Asia are forced by subsidence and reductions of moisture fluxes as a result of the interaction of the mean flow with anomalous zonally symmetric high pressure throughout the Northern Hemisphere. The anomalous zonally symmetric high pressure throughout the Northern Hemisphere occurs simultaneously with cool central and eastern Pacific SST anomalies associated with La Niña and the negative phase of PDV and a warm west Pacific Ocean caused in part by the long-term warming of the west Pacific Ocean.

33 CFR 88.15 - Lights on dredge pipelines.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Lights on dredge pipelines. 88.15... NAVIGATION RULES ANNEX V: PILOT RULES § 88.15 Lights on dredge pipelines. Dredge pipelines that are floating or supported on trestles shall display the following lights at night and in periods of restricted...

33 CFR 88.15 - Lights on dredge pipelines.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Lights on dredge pipelines. 88.15... NAVIGATION RULES ANNEX V: PILOT RULES § 88.15 Lights on dredge pipelines. Dredge pipelines that are floating or supported on trestles shall display the following lights at night and in periods of restricted...

33 CFR 88.15 - Lights on dredge pipelines.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Lights on dredge pipelines. 88.15... NAVIGATION RULES ANNEX V: PILOT RULES § 88.15 Lights on dredge pipelines. Dredge pipelines that are floating or supported on trestles shall display the following lights at night and in periods of restricted...

33 CFR 88.15 - Lights on dredge pipelines.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Lights on dredge pipelines. 88.15... NAVIGATION RULES ANNEX V: PILOT RULES § 88.15 Lights on dredge pipelines. Dredge pipelines that are floating or supported on trestles shall display the following lights at night and in periods of restricted...

33 CFR 88.15 - Lights on dredge pipelines.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Lights on dredge pipelines. 88.15... NAVIGATION RULES ANNEX V: PILOT RULES § 88.15 Lights on dredge pipelines. Dredge pipelines that are floating or supported on trestles shall display the following lights at night and in periods of restricted...

Beneficial Uses of Dredged Material. Proceedings of the Gulf Coast Regional Workshop Held on 26-28 April 1988 in Galveston, Texas

DTIC Science & Technology

1990-02-01

COL John Tudela, Commander of the Galveston District, US Army Corps of Engineers. As a former Pharmacist Mate, third class in the US Marine Corps, I... uti - lizing material from maintenance dredging at the entrance to the harbor. The port commission has lands and containment facilities prepared for...sensitivity. When considering disposal techniques, it is useful to retrace man’s uti - lization of estuaries and waterways. From earliest times, settlement

Regulatory Evaluation of Petroleum Hydrocarbons in Dredged Material: Proceedings of a Workshop Held in Vicksburg, Mississippi on 15-17 March 1988

DTIC Science & Technology

1990-07-01

in Daphnia magna" 8909 Draft TN: Effects of Petroleum Hydrocarbon Bioaccumulation in Aquatic Animals 9009 Input to EPA/CE Implementation Manuals CONT...database for bioaccumulation of the 15 PAHs as indicative of levels of concern for petroleum hydrocarbons in marine and freshwater. ASSESSMENT OF THE PROBLEM...mc I LEIU OCy, JMISCELLANEOUS PAPER EL-90-11 of EREGULATORY EVALUATION OF PETROLEUM HYDROCARBONS IN DREDGED MATERIAL PROCEEDINGS OF A WORKSHOP

Green Ships: Keeping Oceans Blue

ERIC Educational Resources Information Center

Katsioloudis, Petros J.

2010-01-01

The marine transport sector contributes significantly to air and water pollution, particularly in coastal areas. In the oceans, the threat to marine life comes in various forms, such as overexploitation and harvesting, dumping of waste, pollution, alien species, land reclamation, dredging, and global climate change. A congressional research report…

TOXICITY TESTING, RISK ASSESSMENT, AND OPTIONS FOR DREDGED MATRIAL MANAGEMENT

EPA Science Inventory

The U.S. Environmental Protection Agency (U.S. EPA), in conjunction with the U.S. Army Corps of Engineers (U.S. ACE), has lead responsibility for developing guidelines that provide environmental criteria for evaluating proposed discharges of dredged material into U.S. waters. To ...

The Canada Basin compared to the southwest South China Sea: Two marginal ocean basins with hyper-extended continent-ocean transitions

NASA Astrophysics Data System (ADS)

Li, Lu; Stephenson, Randell; Clift, Peter D.

2016-11-01

Both the Canada Basin (a sub-basin within the Amerasia Basin) and southwest (SW) South China Sea preserve oceanic spreading centres and adjacent passive continental margins characterized by broad COT zones with hyper-extended continental crust. We have investigated strain accommodation in the regions immediately adjacent to the oceanic spreading centres in these two basins using 2-D backstripping subsidence reconstructions, coupled with forward modelling constrained by estimates of upper crustal extensional faulting. Modelling is better constrained in the SW South China Sea but our results for the Canada Basin are analogous. Depth-dependent extension is required to explain the great depth of both basins because only modest upper crustal faulting is observed. A weak lower crust in the presence of high heat flow and, accordingly, a lower crust that extends far more the upper crust are suggested for both basins. Extension in the COT may have continued even after seafloor spreading has ceased. The analogous results for the two basins considered are discussed in terms of (1) constraining the timing and distribution of crustal thinning along the respective continental margins, (2) defining the processes leading to hyper-extension of continental crust in the respective tectonic settings and (3) illuminating the processes that control hyper-extension in these basins and more generally.

Multispectral analysis of ocean dumped materials

NASA Technical Reports Server (NTRS)

Johnson, R. W.

1977-01-01

Remotely sensed data were collected in conjunction with sea-truth measurements in three experiments in the New York Bight. Pollution features of primary interest were ocean dumped materials, such as sewage sludge and acid waste. Sewage-sludge and acid-waste plumes, including plumes from sewage sludge dumped by the 'line-dump' and 'spot-dump' methods, were located, identified, and mapped. Previously developed quantitative analysis techniques for determining quantitative distributions of materials in sewage sludge dumps were evaluated, along with multispectral analysis techniques developed to identify ocean dumped materials. Results of these experiments and the associated data analysis investigations are presented and discussed.

46 CFR 44.330 - Obtaining working freeboards for hopper dredges.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 2 2011-10-01 2011-10-01 false Obtaining working freeboards for hopper dredges. 44.330... SERVICE LIMITED DOMESTIC VOYAGES Rules for Assigning Working Freeboards to Hopper Dredges § 44.330 Obtaining working freeboards for hopper dredges. A hopper dredge may be issued a working freeboard on a...

46 CFR 44.330 - Obtaining working freeboards for hopper dredges.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Obtaining working freeboards for hopper dredges. 44.330... SERVICE LIMITED DOMESTIC VOYAGES Rules for Assigning Working Freeboards to Hopper Dredges § 44.330 Obtaining working freeboards for hopper dredges. A hopper dredge may be issued a working freeboard on a...

Field Verification Program (Aquatic Disposal): Comparison of Field and Laboratory Bioaccumulation of Organic and Inorganic Contaminants from Black Rock Harbor Dredged Material

DTIC Science & Technology

1988-05-01

include poly- chlorinated biphenyls (PCBs) and related chlorinated pesticides of similar polarity in addition to the petroleum hydrocarbons . The...Ui It tILL (JV: FIELD VERIFICATION PROGRAM (AQUATIC DISPOSAL).’Wh TECHNICAL REPORT D-87-6 COMPARISON OF FIELD AND LABORATORY BIOACCUMULATION OF...Laboratory Bioaccumulation of Organic and Inorganic Contaminants from Black Rock Harbor Dredged Material 12 PERSONAL AUTHOR(S) Lake, James L.; Galloway

Geotechnical and mineralogical characterisations of marine-dredged sediments before and after stabilisation to optimise their use as a road material.

PubMed

Saussaye, L; van Veen, E; Rollinson, G; Boutouil, M; Andersen, J; Coggan, J

2017-12-01

Dredging activities to extend, deepen and maintain access to harbours generate significant volumes of waste dredged material. Some ways are investigated to add value to these sediments. One solution described here is their use in road construction following treatment with hydraulic binders. This paper presents the characterisation of four sediments, in their raw state and after 90 days of curing following stabilisation treatment with lime and cement, using a combination of novel and established analytical techniques to investigate subsequent changes in mineralogy. These sediments are classified as fine, moderately to highly organic and highly plastic and their behaviour is linked to the presence of smectite clays. The main minerals found in the sediments using X-ray diffraction (XRD) and automated mineralogy are quartz, calcite, feldspars, aluminium silicates, pyrite and halite. Stabilisation was found to improve the mechanical performances of all the sediments. The formation of cementitious hydrates was not specifically detected using automated mineralogy or XRD. However, a decrease in the percentage volume of aluminium silicates and aluminium-iron silicates and an increase of the percentage volume of feldspars and carbonates was observed.

Egg cases of the graytail skate Bathyraja griseocauda and the cuphead skate Bathyraja scaphiops from the south-west Atlantic Ocean.

PubMed

Mabragaña, E; Vazquez, D M; Gabbanelli, V; Sabadin, D; Barbini, S A; Lucifora, L O

2017-09-01

Egg cases of Bathyraja griseocauda were larger (140-142 mm in length) than those of Bathyraja scaphiops (88-90 mm in length) and their surface was relatively smooth, without denticles, prickles or any ornamentation. Egg cases of B. scaphiops had a relative coarse surface, covered with prickles of similar size. An identification key for the all described egg cases from Bathyraja occurring in the south-west Atlantic Ocean is provided. © 2017 The Fisheries Society of the British Isles.

Predicting dredging-associated effects to coral reefs in Apra Harbor, Guam - Part 1: Sediment exposure modeling.

PubMed

Gailani, Joseph Z; Lackey, Tahirih C; King, David B; Bryant, Duncan; Kim, Sung-Chan; Shafer, Deborah J

2016-03-01

Model studies were conducted to investigate the potential coral reef sediment exposure from dredging associated with proposed development of a deepwater wharf in Apra Harbor, Guam. The Particle Tracking Model (PTM) was applied to quantify the exposure of coral reefs to material suspended by the dredging operations at two alternative sites. Key PTM features include the flexible capability of continuous multiple releases of sediment parcels, control of parcel/substrate interaction, and the ability to efficiently track vast numbers of parcels. This flexibility has facilitated simulating the combined effects of sediment released from clamshell dredging and chiseling within Apra Harbor. Because the rate of material released into the water column by some of the processes is not well understood or known a priori, the modeling approach was to bracket parameters within reasonable ranges to produce a suite of potential results from multiple model runs. Sensitivity analysis to model parameters is used to select the appropriate parameter values for bracketing. Data analysis results include mapping the time series and the maximum values of sedimentation, suspended sediment concentration, and deposition rate. Data were used to quantify various exposure processes that affect coral species in Apra Harbor. The goal of this research is to develop a robust methodology for quantifying and bracketing exposure mechanisms to coral (or other receptors) from dredging operations. These exposure values were utilized in an ecological assessment to predict effects (coral reef impacts) from various dredging scenarios. Copyright © 2015. Published by Elsevier Ltd.

School Learning Materials on Water Problems of New Mexico and the Southwest.

ERIC Educational Resources Information Center

Buethe, Chris; And Others

Schools typically make no special efforts to prepare students to cope with present and anticipated water problems. Using this as a premise, the objective of this study was to prepare a set of mediated learning packages based upon water problems of New Mexico and the dry regions of the Southwest. These learning materials were prepared and field…

Projected entrainment of fish resulting from aggregate dredging.

PubMed

Drabble, Ray

2012-02-01

Previous research to assess impacts from aggregate dredging has focussed on infaunal species with few studies made of fish entrainment. Entrainment evidence from hydraulic dredging studies is reviewed to develop a sensitivity index for benthic fish. Environmental monitoring attendant with the granting of new licences in the Eastern Channel Region (ECR) in 2006 offers a unique opportunity to assess the effects of dredging upon fish. Projected theoretical fish entrainment rates are calculated based upon: abundance data from 4m beam trawl sampling of fish species over the period 2005-2008; sensitivity data; and dredging activity and footprint derived from Electronic monitoring System (EMS) data. Results have been compared with actual entrainment rates and also against summary results from independent analysis of the changes in fish population over the period 2005-2008 (Drabble, 2012). The case is made for entrainment surveys to form part of impact monitoring for marine aggregate dredging. Copyright © 2011 Elsevier Ltd. All rights reserved.

Collapsed Thunderstorm, Southwest Pacific Ocean

NASA Image and Video Library

1992-05-16

STS049-71-042 (8 May 1992) --- This photograph, taken from the Earth-orbiting Space Shuttle Endeavour, shows a collapsed thunderstorm in the southwestern Pacific Ocean. The clouds were pushed from this circular area of the ocean's surface by relatively cool air that spread downward and outward from a dying thunderstorm. Around the edges of the downdrafted air, new, though smaller, storms are developing. The photo was taken on May 8, 1992, between Borneo and the Philippine island of Mindoro. Two coral atolls can be seen near the center of the photograph. The crew members used a handheld Hasselblad camera, 250-mm lens, color film to expose the image.

An overview of dredging operations in the Chesapeake Bay. [environment effects and coastal ecology

NASA Technical Reports Server (NTRS)

Silver, R. H.

1978-01-01

Maintenance of the Baltimore and the Newport News/Norfolk harbors as well as of the Chesapeake and Delaware Canal is accomplished by different dredging operations which depend on the amount and type of material to be moved, water depth, and location of disposal sites. Methods for determining the physical or chemical-biological interactive effects of these activities on the environment and on the shellfish and finfish industries on the Bay are discussed. The types of dredges used are classed according to their mode of operation.

Impacts to Dungeness Crab from the Southwest Washington Littoral Drift Restoration Project

DOE Office of Scientific and Technical Information (OSTI.GOV)

Williams, Greg D.; Kohn, Nancy P.; Pearson, Walter H.

2005-11-09

The Benson Beach littoral drift restoration project is a demonstration project that will replenish sand on Benson Beach, the public beach north of the North Jetty at the mouth of the Columbia River (MCR), using material dredged from the river during normal maintenance dredging of the navigational channel. A U.S. Army Corps of Engineers (Corps) proposal involves pumping the material from a sump area on the south side of the jetty to Benson Beach using a cutter suction dredge, also known as a pipeline dredge. If this one-time demonstration project proves feasible and successful, up to a million cubic yardsmore » of sediment could be used to replenish the outer coast littoral drift system in successive years by the same process. The primary goal of this study was to assess the potential risk of impacts to Dungeness crab from the proposed Benson Beach littoral drift restoration process of using the cutter suction dredge to move sediment from the proposed sump area on one side of the North Jetty to the beach on the other side of the jetty. Because there are no direct measurements of crab entrainment by pipeline dredge operating outside of the lower Columbia River navigation channel, dredge impacts for the proposed demonstration project were estimated using a modification of the dredge impact model (DIM) of Armstrong et al. (1987). The model estimates adult equivalent loss (AEL) of crabs using crab population density from trawl surveys, dredge project information (gear type, season, location, volume), and an entrainment function relating crab population density to entrainment by the dredge. The input used in applying the DIM to the Benson Beach littoral drift restoration included the specific dredging scenario provided by the Corps, existing data on crab density in previously proposed sump areas, and a series of entrainment functions. A total of fourteen scenarios were modeled and the outcomes compared with six reference scenarios intended to represent realistic to

An 'Early Warning System' for the prevention of dredging potential impacts on sensitive areas

NASA Astrophysics Data System (ADS)

Piermattei, Viviana; Martellucci, Riccardo; Pierattini, Alberto; Bonamano, Simone; Paladini de Mendoza, Francesco; Albani, Marta; Stefanì, Chiara; Madonia, Alice; Fersini, Giorgio; Marcelli, Marco

2016-04-01

Coastal marine ecosystems are increasingly subject to multiple pressures and stressors produced by the effects of human activities. Intense and frequent disturbances which affect marine environment can derive from dredging activity, which is a fundamental management for most ports and harbours. The potential environmental effects of dredging procedures are generally due to the excavation of material from the sea bottom and the relocation elsewhere for disposal, overflow from the dredger and loss of material from pipelines during transport. Depending on the location and the intensity of these activities the marine environment, particularly sensitive areas, may be affected by dredging. The main environmental effects can be associated with suspended sediments and increases in turbidity into the water column, which can have adverse effects on marine animals and plants by reducing light penetration and by physical disturbance. For this reason it is fundamental to implement a real time monitoring system to control and prevent negative effects, enabling a rapid response to adverse water quality conditions and a fast activation of mitigation procedures, in agreement with all the reference authorities. In this work we present the development of an innovative 'Early Warning System' based on fixed stations, ad hoc in situ surveys and forecasting models, which was applied to a dredging activity carried out in the Gulf of Gaeta (Latium, Italy). It represents an extension of the C-CEMS (Civitavecchia Coastal Environmental Monitoring System) network, which is operative in the Tyrrhenian sea since 2005.

Sand dredging and environmental efficiency of artisanal fishermen in Lagos state, Nigeria.

PubMed

Sowunmi, Fatai A; Hogarh, Jonathan N; Agbola, Peter O; Atewamba, Calvin

2016-03-01

Environmentally detrimental input (water turbidity) and conventional production inputs were considered within the framework of stochastic frontier analysis to estimate technical and environmental efficiencies of fishermen in sand dredging and non-dredging areas. Environmental efficiency was low among fishermen in the sand dredging areas. Educational status and experience in fishing and sand dredging were the factors influencing environmental efficiency in the sand dredging areas. Average quantity of fish caught per labour- hour was higher among fishermen in the non-dredging areas. Fishermen in the fishing community around the dredging areas travelled long distance in order to reduce the negative effect of sand dredging on their fishing activity. The study affirmed large household size among fishermen. The need to regulate the activities of sand dredgers by restricting license for sand dredging to non-fishing communities as well as intensifying family planning campaign in fishing communities to reduce the negative effect of high household size on fishing is imperative for the sustainability of artisanal fishing.

Temporal Patterns in Seawater Quality from Dredging in Tropical Environments.

PubMed

Jones, Ross; Fisher, Rebecca; Stark, Clair; Ridd, Peter

2015-01-01

Maintenance and capital dredging represents a potential risk to tropical environments, especially in turbidity-sensitive environments such as coral reefs. There is little detailed, published observational time-series data that quantifies how dredging affects seawater quality conditions temporally and spatially. This information is needed to test realistic exposure scenarios to better understand the seawater-quality implications of dredging and ultimately to better predict and manage impacts of future projects. Using data from three recent major capital dredging programs in North Western Australia, the extent and duration of natural (baseline) and dredging-related turbidity events are described over periods ranging from hours to weeks. Very close to dredging i.e. <500 m distance, a characteristic features of these particular case studies was high temporal variability. Over several hours suspended sediment concentrations (SSCs) can range from 100-500 mg L-1. Less turbid conditions (10-80 mg L-1) can persist over several days but over longer periods (weeks to months) averages were <10 mg L-1. During turbidity events all benthic light was sometimes extinguished, even in the shallow reefal environment, however a much more common feature was very low light 'caliginous' or daytime twilight periods. Compared to pre-dredging conditions, dredging increased the intensity, duration and frequency of the turbidity events by 10-, 5- and 3-fold respectively (at sites <500 m from dredging). However, when averaged across the entire dredging period of 80-180 weeks, turbidity values only increased by 2-3 fold above pre-dredging levels. Similarly, the upper percentile values (e.g., P99, P95) of seawater quality parameters can be highly elevated over short periods, but converge to values only marginally above baseline states over longer periods. Dredging in these studies altered the overall probability density distribution, increasing the frequency of extreme values. As such, attempts

Temporal Patterns in Seawater Quality from Dredging in Tropical Environments

PubMed Central

Jones, Ross; Fisher, Rebecca; Stark, Clair; Ridd, Peter

2015-01-01

Maintenance and capital dredging represents a potential risk to tropical environments, especially in turbidity-sensitive environments such as coral reefs. There is little detailed, published observational time-series data that quantifies how dredging affects seawater quality conditions temporally and spatially. This information is needed to test realistic exposure scenarios to better understand the seawater-quality implications of dredging and ultimately to better predict and manage impacts of future projects. Using data from three recent major capital dredging programs in North Western Australia, the extent and duration of natural (baseline) and dredging-related turbidity events are described over periods ranging from hours to weeks. Very close to dredging i.e. <500 m distance, a characteristic features of these particular case studies was high temporal variability. Over several hours suspended sediment concentrations (SSCs) can range from 100–500 mg L-1. Less turbid conditions (10–80 mg L-1) can persist over several days but over longer periods (weeks to months) averages were <10 mg L-1. During turbidity events all benthic light was sometimes extinguished, even in the shallow reefal environment, however a much more common feature was very low light ‘caliginous’ or daytime twilight periods. Compared to pre-dredging conditions, dredging increased the intensity, duration and frequency of the turbidity events by 10-, 5- and 3-fold respectively (at sites <500 m from dredging). However, when averaged across the entire dredging period of 80–180 weeks, turbidity values only increased by 2–3 fold above pre-dredging levels. Similarly, the upper percentile values (e.g., P99, P95) of seawater quality parameters can be highly elevated over short periods, but converge to values only marginally above baseline states over longer periods. Dredging in these studies altered the overall probability density distribution, increasing the frequency of extreme values. As such

Using a modified dredging elutriate testing approach to evaluate potential aquatic impacts associated with dredging a large freshwater industrial harbor.

PubMed

Watson-Leung, Trudy; Graham, Matt; Hartman, Erin; Welsh, Paul G

2017-01-01

Potential adverse impacts to the aquatic environment should be minimized whenever possible during an environmental dredging project by selecting realistic and technically feasible environmental targets. These targets need to balance short term impacts with the longer term benefit of removing contaminated sediments from the environment. Environmental dredging is part of the planned remediation of Randle Reef (a 60 hectare zone of mostly PAH-contaminated sediments) in Hamilton, Ontario, Canada. In this study, we describe the results of dredging elutriate toxicity testing (DETE) to assess the potential risks from dredging this PAH contaminated site. A modified elutriate preparation method intended as an alternative measure of conditions within the dredging plume was assessed with both standard water column species (Daphnia magna and fathead minnow [Pimephales promelas]) and alternative benthic and epibenthic test organisms (Chironomus dilutus and Hyalella azteca). The standard DETE test was also conducted with H. azteca to compare with the modified DETE results. The greatest toxic response was seen in the alternative test species; however, the modified DETE method resulted in less toxicity than the standard protocol. The relationship between toxicity results and chemical and/or physical characteristics of the samples was examined, but differences in toxicity could only be explained by differences in the total suspended solids concentrations in the elutriate samples. Challenges associated with DETE assessment of PAH-contaminated sediments and the implications for establishing dredging benchmarks are discussed. Integr Environ Assess Manag 2017;13:155-166. © 2016 SETAC. © 2016 SETAC.

Carapidae larvae (Acanthomorpha, Paracanthopterygii, Ophidiiformes) from the oceanic region of the southwest Atlantic Ocean off Brazil (12 22°S)

NASA Astrophysics Data System (ADS)

Namiki, C.; Bonecker, A. C. T.; de Castro, M. S.

2007-02-01

We report the occurrence and distribution of Carapidae larvae in the southwest Atlantic Ocean, between Real River (12°S) and São Tomé Cape (22°S), off Brazil. Carapidae larvae were collected during three oceanographic cruises: spring 1998, winter 1999 and autumn 2000. The hauls were conducted obliquely from a maximum depth of 200 m, during day and night, with bongo nets 330- and 500-μm mesh size. Three species were recorded in this study: Carapus bermudensis, Echiodon dawsoni and Snyderidia canina. Only one C. bermudensis was collected during the winter cruise off the Salvador coast (13°S). Twenty-one larvae of E. dawsoni were collected during the three cruises between 14.5° and 22°S, including some at the banks of Vitória-Trindade Ridge. One S. canina larva occurred, during the spring in the north coast of Rio de Janeiro (22°S).

Supracrustal origin of plagiogranite from the Gallieni Fracture Zone, Southwest Indian Ridge

NASA Astrophysics Data System (ADS)

Zhu, Jihao; Li, Zhenggang; Chu, Fengyou; Fu, Bin; Dong, Yanhui; Chen, Ling; Liu, Jiqiang

2017-04-01

Small amounts of felsic rocks such as tonalite, trondjhemite and diorite often called oceanic plagiogranites were found at all structure levels of the oceanic crust. They can be formed either by partial melting of hydrated gabbros and/or sheeted dikes, or by late-stage differentiation of parental mid-ocean ridge basalt melts. Here we report a granodiorite sampled in the Gallieni Fracture Zone, Southwest Indian Ridge, shows no ocean crust affinity but the nature of the continental crust. The granodiorite is extremely enriched in K2O (3.72%) and its rare-earth-element distribution pattern is incomparable to any type of oceanic plagiogranites from mid-ocean ridge and ophiolites, but similar to the Upper Continental Crust. Moreover, the in-situ zircon O isotopes (δ18O=5.9-7.5‰) are much higher than the plagiogranites from all the tectonic settings relevant to ocean crust generation, while Hf isotope compositions (ɛHf(0) =-4.0 to -7.9) are much lower than global oceanic basalts. In addition, the granodiorite suffered low-grade metamorphism as reflected by the penetration of late-stage felsic veins and the occurrence of metamorphic minerals such as epidote and chlorite. Secondary vein quartz has negative δ18O values as low as -3.9‰, suggesting the involvement of meteoric water. Zircon U-Pb age (183.7±1.2Ma) shows that the granodiorite was formed contemporarily with Karoo volcanism associating with the breakup of Gondwanaland. We suggest that it may be formed by the anataxis of continental crustal materials by underplated Karoo basaltic magma. Combining our unreported high-grade quartzite with zircon U-Pb ages of more than 500Ma and a Jurassic quartz diorite reported earlier which all sampled in or near the Gallieni Fracture Zone, we propose that a continental block probably from the South Madagascar was split during continental breakup but retained near the ridge segment as a result of repeated ridge jumping and transform migration. Keywords: zircon Hf-O isotopes

Environmental effects of dredging. Documentation of the settle module for ADDAMS: Design of confined disposal facilities for solids retention and initial storage. Technical notes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hayes, D.F.; Schroeder, P.R.

This technical note documents the SETTLE computer program which facilitates the design of a confined disposal facility (CDF) to retain solids, provide initial storage, and meet effluent discharge limitations for suspended solids during a dredged matenal disposal operation. Detailed information can be found in Engineer Manual 1110-2-5027, Confined Dredged Material Disposal. SETTLE is a part of the Automated Dredging and Disposal Alternatives Management System (ADDAMS).

Survey and evaluation of contaminants in earthworms and in soils derived from dredged material at confined disposal facilities in the Great Lakes region

USGS Publications Warehouse

Beyer, W.N.; Stafford, C.

1993-01-01

Soils derived from dredged material were collected, together with earthworms from nine confined disposal facilities located in the Great Lakes Region. These samples were analyzed for 18 elements, 11 organochlorine pesticides, PCBs, and 24 polycyclic aromatic hydrocarbons. The concentrations detected in earthworms were evaluated in terms of their potential hazard to wildlife, which for the sake of the evaluation were assumed to prey entirely either on earthworms or on other soil invertebrates having similar concentrations. The soil concentrations (dry wt.) of the contaminants of greatest concern were < 1.9 to 32 ppm Cd, < 0.053 to 0.94 ppm Hg, 4.6 to 550 ppm Pb, and < 0.1 to 1.0 ppm PCBs. The concentrations in earthworms (dry wt., ingested soil included) were as high as 91 ppm Cd, 1.6 ppm Hg, 200 ppm Pb, and 1.8 ppm PCBs. Based on laboratory toxicity studies of relatively sensitive species, and on concentration factors calculated from the earthworm and soil data, we estimated that lethal or serious sublethal effects on wildlife might be expected at concentrations of 10 ppm Cd, 3 ppm Hg, 670 ppm Pb, and 1.7 ppm PCBs in alkaline surface soils derived from dredged material. Concentrations of polycyclic aromatic hydrocarbons in earthworms were well below those in soil.

Short-term response of subadult white sturgeon to hopper dredge disposal operations

USGS Publications Warehouse

Parsley, Michael J.; Popoff, Nicholas D.; Romine, Jason G.

2011-01-01

The effect of dredged-material disposal operations on the behavior of seven white sturgeon Acipenser transmontanus (50–101 cm fork length) was examined by analysis of the movements and depth use of these fish before, during, and after a series of hopper dredge disposal operations in the lower Columbia River. Analyses of fish locations showed that 12 flow-lane disposal operations within a 24-h period had minimal effect on subadult white sturgeon behavior; six of the seven fish showed slight attraction to the disposal area during disposals, and one fish increased its distance from the disposal area. The core area for all fish combined shifted toward the disposal area during disposals. In the 24 h after completion of the disposal operations the fish core areas shifted back toward those areas occupied before the disposals. The rates of movement, depths used, and diel movement patterns of the white sturgeon showed little change over all periods, suggesting that natural behaviors were not altered during and immediately after hopper dredge disposal operations.

43 CFR 15.3 - Dredging, filling, excavating and building activities.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 43 Public Lands: Interior 1 2013-10-01 2013-10-01 false Dredging, filling, excavating and building activities. 15.3 Section 15.3 Public Lands: Interior Office of the Secretary of the Interior KEY LARGO CORAL REEF PRESERVE § 15.3 Dredging, filling, excavating and building activities. No dredging, excavating, or...

43 CFR 15.3 - Dredging, filling, excavating and building activities.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 43 Public Lands: Interior 1 2014-10-01 2014-10-01 false Dredging, filling, excavating and building activities. 15.3 Section 15.3 Public Lands: Interior Office of the Secretary of the Interior KEY LARGO CORAL REEF PRESERVE § 15.3 Dredging, filling, excavating and building activities. No dredging, excavating, or...

43 CFR 15.3 - Dredging, filling, excavating and building activities.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 43 Public Lands: Interior 1 2012-10-01 2011-10-01 true Dredging, filling, excavating and building activities. 15.3 Section 15.3 Public Lands: Interior Office of the Secretary of the Interior KEY LARGO CORAL REEF PRESERVE § 15.3 Dredging, filling, excavating and building activities. No dredging, excavating, or...

43 CFR 15.3 - Dredging, filling, excavating and building activities.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Dredging, filling, excavating and building activities. 15.3 Section 15.3 Public Lands: Interior Office of the Secretary of the Interior KEY LARGO CORAL REEF PRESERVE § 15.3 Dredging, filling, excavating and building activities. No dredging, excavating, or...

43 CFR 15.3 - Dredging, filling, excavating and building activities.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 43 Public Lands: Interior 1 2011-10-01 2011-10-01 false Dredging, filling, excavating and building activities. 15.3 Section 15.3 Public Lands: Interior Office of the Secretary of the Interior KEY LARGO CORAL REEF PRESERVE § 15.3 Dredging, filling, excavating and building activities. No dredging, excavating, or...

Magnetization of lower oceanic crust and upper mantle

NASA Astrophysics Data System (ADS)

Kikawa, E.

2004-05-01

The location of the magnetized rocks of the oceanic crust that are responsible for sea-floor spreading magnetic anomalies has been a long-standing problem in geophysics. The recognition of these anomalies was a key stone in the development of the theory of plate tectonics. Our present concept of oceanic crustal magnetization is much more complex than the original, uniformly magnetized model of Vine-Matthews-Morley Hypothesis. Magnetic inversion studies indicated that the upper oceanic extrusive layer (Layer 2A of 0.5km thick) was the only magnetic layer and that it was not necessary to postulate any contribution from deeper parts of oceanic crust. Direct measurements of the magnetic properties of the rocks recovered from the sea floor, however, have shown that the magnetization of Layer 2A, together with the observations that this layer could record geomagnetic field reversals within a vertical section, is insufficient to give the required size of observed magnetic anomalies and that some contribution from lower intrusive rocks is necessary. Magnetization of oceanic intrusive rocks were observed to be reasonably high enough to contribute to sea-floor spreading magnetic anomalies, but were considered somewhat equivocal until late 1980Os, in part because studies had been conducted on unoriented dredged and ophiolite samples and on intermittent DSDP/ODP cores. Since ODP Leg 118 that cored and recovered continuous 500m of oceanic intrusive layer at Site 735B, Southwest Indian Ridge with an extremely high recovery of 87 percent, there have been several ODP Legs (legs 147, 153, 176, 179 and 209) that were devoted to drilling gabbroic rocks and peridotites. In terms of the magnetization intensities, all of the results obtained from these ODP Legs were supportive of the model that a significant contribution must come from gabbros and peridotites and the source of the lineated magnetic anomalies must reside in most of the oceanic crust as well as crust-mantle boundary

Dangerous compounds in the dredged material from the sea - Assessment of the current approach to the evaluation of contaminations based on the data from the Polish coastal zone (the Baltic Sea).

PubMed

Staniszewska, Marta; Boniecka, Helena

2018-05-01

It has been shown that the current approach to the assessment of contamination in the sediments obtained during the dredging works in the Baltic countries indicates the presence of "non-contaminated" dredged material. The concentration limits of heavy metals, Polycyclic Aromatic Hydrocarbons (PAHs), Polychlorinated Biphenyls (PCBs) have been exceeded only in 1% of the samples obtained during the dredging works (2005-2015) within the Polish coastal zone. After 2008, no contaminated sediments have been found. Also, in the remaining Baltic countries, sediments are very rarely contaminated. As a result of this assessment, the sediments can be stored in the sea or have a practical application. However, it has been questioned whether the large cost of determining the numerous chemical parameters is justified. It has been proposed to carry out simple screening tests. Following the preliminary screening, the decision on more detailed (and expensive) chemical tests of individual pollutants would be made. Copyright © 2018 Elsevier Ltd. All rights reserved.

Eocene tectonic compression in Northern Zealandia: Magneto-biostratigraphic constraints from the sedimentary records of New Caledonia (Southwest Pacific Ocean)

NASA Astrophysics Data System (ADS)

Dallanave, E.; Agnini, C.; Pascher, K. M.; Maurizot, P.; Bachtadse, V.; Hollis, C. J.; Dickens, G. R.; Collot, J.; Sevin, B.; Strogen, D.; Monesi, E.

2017-12-01

Published seismic profiles acquired from the Tasman Sea and northern Zealandia area (southwest Pacific) point to a widespread Eocene convergent deformation of oceanic and continental crust, with reverse faults and uplift (Tectonic Event of the Cenozoic in the Tasman Area; TECTA). The TECTA is interpreted as the precursor of the Tonga-Kermadec subduction initiation. Grande Terre is the main island of the New Caledonia archipelago and the largest emergent portion of northern Norfolk Ridge (part of northern Zealandia). Eocene sedimentary records exposed in Grande Terre contain a transition from pelagic micrite to terrigenous-rich calciturbidites, marking a shift from passive margin to convergent tectonic regime. This could represent the local expression of the convergence inception observed on a regional scale. We conducted an integrated magneto-biostratigraphic study, based on calcareous nannofossil and radiolaria, of two early-middle Eocene records cropping out near Noumea (southwest Grande Terre) and Koumac (northwest Grande Terre). The natural remanent magnetization of the sediments is complicated by multiple vector components, likely related to the late Eocene obduction, but a characteristic remanent magnetization has been successfully isolated. Overall the record spans from magnetic polarity Chron C23n to C18n, i.e. from 51 to 39 Ma. In this robust magnetic polarity-based chronological frame, the pelagic micrite to terrigenous-rich calciturbidites occurred near the top of Chron C21n and is dated 46 Ma. Furthermore, the magnetic mineral assemblage within part of the calciturbidites consists of hematite associated with maghemite. This association indicates emergent land as source of the terrigenous, suggesting a considerable uplift. Because 94% of the Zealandia continent is submerged, ocean drilling is needed to gauge the full extent and timing of Eocene compressive deformation revealed by the seismic profiles acquired in the Tasman area. This is a primary aim of

Impacts of the 2004 Indian ocean tsunami on the southwest coasts of Sri Lanka

USGS Publications Warehouse

Morton, Robert A.; Goff, John A.; Nichol, Scott L.

2007-01-01

The 2004 Indian Ocean tsunami caused major landscape changes along the southwest coasts of Sri Lanka that were controlled by the flow, natural topography and bathymetry, and anthropogenic modifications of the terrain. Landscape changes included substantial beach erosion and scouring of return-flow channels near the beach, and deposition of sand sheets across the narrow coastal plain. In many areas tsunami deposits also included abundant building rubble due to the extensive destruction of homes and businesses in areas of dense development. Trim lines and flow directions confirmed that shoreline orientation and wave refraction from embayments and rock-anchored headlands locally focused the flow and amplified the inundation. Tsunami deposits were 1 to 36 cm thick but most were less than 25 cm thick. Deposit thickness depended partly on antecedent topography. The deposits were composed of coarse to medium sand organized into a few sets of plane parallel laminae that exhibited overall upward fining and landward thinning trends.

Dredging Research Program: Practices and Problems Associated with Economic Loading and Overflow of Dredge Hoppers and Scows

DTIC Science & Technology

1990-10-01

Services No. EB687D020, 20 January 1987, as a part of the Dredging Research Program (DRP), managed by the WES Coastal Engineering Research Center (CERC...with the bottom. The bottom sediments are entrained with the ambient water, lifted hydraulically by the dredge pumps, and discharged into the hop - pers...in a hopper. Some of these are particle size, hopper capacity and opening area, settling velocity, flow velocity in the hop - per, inflow

Dredging: An Annotated Bibliography on Operations, Equipment, and Processes. Revision.

DTIC Science & Technology

1982-03-01

establishing producing centers, enterprises, financial planning, and technical specifications for plant and equipment. Drilling and laboratory results are...summarised, and resource, market, technological and environmental bases described. Prospect drilling of calcareous sandstone (kurkar and calcarenite...Automation; Pumps and impellers; Cavitation; Cost and econ- omy of dredging; Drilling and blasting; Spoil disposal; Deep sea dredg- ing; River dredging

Is the negative IOD during 2016 the reason for monsoon failure over southwest peninsular India?

NASA Astrophysics Data System (ADS)

Sreelekha, P. N.; Babu, C. A.

2018-01-01

The study investigates the mechanism responsible for the deficit rainfall over southwest peninsular India during the 2016 monsoon season. Analysis shows that the large-scale variation in circulation pattern due to the strong, negative Indian Ocean Dipole phenomenon was the reason for the deficit rainfall. Significant reduction in the number of northward-propagating monsoon-organized convections together with fast propagation over the southwest peninsular India resulted in reduction in rainfall. On the other hand, their persistence for longer time over the central part of India resulted in normal rainfall. It was found that the strong convection over the eastern equatorial Indian Ocean creates strong convergence over that region. The combined effect of the sinking due to the well-developed Walker circulation originated over the eastern equatorial Indian Ocean and the descending limb of the monsoon Hadley cell caused strong subsidence over the western equatorial Indian Ocean. The tail of this large-scale sinking extended up to the southern parts of India. This hinders formation of monsoon-organized convections leading to a large deficiency of rainfall during monsoon 2016 over the southwest peninsular India.

Documentation of the runqual module for ADDAMS: Comparison of predicted runoff water quality with standards. Environmental effects of dredging. Technical notes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schroeder, P.R.; Gibson, A.C.; Dardeau, E.A.

This technical note has a twofold purpose: to describe a technique for comparing the predicted quality of surface runoff from confined dredged material disposal areas with applicable water quality standards and to document a computer program called RUNQUAL, written for that purpose as a part of the Automated Dredging and Disposal Alternatives Management System (ADDAMS).

Environmental effects of dredging. Documentation of the efqual module for ADDAMS: Comparison of predicted effluent water quality with standards. Technical notes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Palermo, M.R.; Schroeder, P.R.

This technical note describes a technique for comparison of the predicted quality of effluent discharged from confined dredged material disposal areas with applicable water quality standards. This note also serves as documentation of a computer program called EFQUAL written for that purpose as part of the Automated Dredging and Disposal Alternatives Management System (ADDAMS).

Dredging Operations Technical Support Program: Engineering Design and Environmental Assessment of Dredged Material Overflow from Hydraulically Filled Hopper Barges in Mobile Bay, Alabama

DTIC Science & Technology

1990-09-01

turbid estuarine habitats such as Mobile Bay are very tolerant of moderately high concentrations of suspended sediments and thin layers of sediment...GULF OF MEXIC BAYOU 4M 2CAE SI2LTK Fiur 3. DsrbuinoAedmnTyesi oie a fo IsphordingLT anCLmb190 PART III: DREDGING EQUIPMENT AND OPERATIONAL TECHNIQUES...increase in ambient turbidity was noted. Water samples were collected at surface, middepth, and bottom. The sampling boats proceeded across their

Dredging-related mobilisation of trace metals: a case study in The Netherlands.

PubMed

van den Berg, G A; Meijers, G G; van der Heijdt, L M; Zwolsman, J J

2001-06-01

Mobilisation of contaminants is an important issue in environmental risk assessment of dredging projects. This study has aimed at identifying the effects of dredging on mobilisation of trace metals (Zn, Cu, Cd and Pb). The intensities and time scales of trace metal mobilisation were investigated during an experimental dredging project conducted under field conditions. The loss of contaminated dredge spoil is mainly reflected by increasing levels of trace metals in the suspended matter, dissolved trace metal concentrations in the water column are not significantly influenced by the dredging activities. This indicates a strong binding mechanism of trace metals to the solid phase or a fast redistribution over sorptive phases in response to oxidation of e.g. trace metal sulphides. Given the differences in levels of reactive phases (Mn, Fe, sulphides and organic matter) between the riverine suspended matter and the sediments, changes in the levels of these parameters in the suspended matter upon dredging may give information on the processes influencing the behaviour of trace metals and on the potential loss of sediment during dredging operations. Therefore, we recommend to routinely measure these parameters in studies on contaminant behaviour related to dredging activities.

Assessing Impacts of Navigation Dredging on Atlantic Sturgeon (Acipenser oxyrinchus)

DTIC Science & Technology

2014-11-01

fishes and insect larvae (Smith 1985, Dadswell 2006). Shallow water shoals located adjacent to both sides of the Federal navigation channel, provide a...incision was closed using sterile resorbitive suture material with four to five simple interrupted stitches. An iodine disinfectant was applied to the...1976). Assessment of techniques used to quantify salmon smolt entrainment by a hydraulic suction hopper dredge in the Fraser River estuary. Environment

Environmental effects of dredging on sediment nutrients, carbon and granulometry in a tropical estuary.

PubMed

Nayar, S; Miller, D J; Hunt, A; Goh, B P L; Chou, L M

2007-04-01

This monitoring study encompassed a period prior to dredging, during dredging and post dredging between July 1999 to June 2000 in Ponggol estuary located along the northeastern coast of Singapore. Mean concentrations of sediment nutrients in mg x Kg(-1) (+/- standard error of means) prior to dredging, during dredging and post dredging were 9.75 +/- 4.24, 8.18 +/- 4.29 and 11.46 +/- 4.74 for ammonium, 0.08 +/- 0.05, 0.06 +/- 0.02 and 0.09 +/- 0.01 for nitrite, 0.04 +/- 0.04, 0.11 +/- 0.17 and 0.25 +/- 0.30 for nitrate, 4.83 +/- 3.48, 0.77 +/- 0.48 and 8.33 +/- 9.73 for phosphate respectively. Pre dredge, dredge and post dredge levels of total carbon (TC) were 18.5 +/- 3.7, 20.2 +/- 3.5 and 34.6 +/- 12.0, of total organic carbon (TOC) were 10.5 +/- 2.9, 19.5 +/- 3.6 and 34.6 +/- 12.0 and of total inorganic carbon (TIC) were 7.9 +/- 1.0, 0.7 +/- 0.4 and non detectable in the sediments, respectively. Both, sediment nutrients and carbon registered lower concentrations with onset of dredging, with the exception of nitrate and TOC. A shift in sedimentary carbon from inorganic carbon to organic carbon was also observed with the onset of the dredging activities when the organically enriched historically contaminated layer was exposed. Sediment granulometry showed that the sediments in the estuary were predominantly silt and clay prior to dredging, which changed to sand with onset of dredging. Silt load in the sediments was highest post-dredge. Sediment nutrients and sediment organic carbon were observed to associate with the finer fractions (silt and clay) of sediments. Finer fractions of sediments get resuspended during a dredging event and are dispersed spatially as the result of tides and water movements. Prior to this study, the potential for nutrient release and sediment granulometry due to dredging have been suggested, but there have been few studies of it, especially in the tropics. The baseline information gathered from this study could be used to work out effective

Spatial Patterns in Water Quality Changes during Dredging in Tropical Environments

PubMed Central

Fisher, Rebecca; Stark, Clair; Ridd, Peter; Jones, Ross

2015-01-01

Dredging poses a potential risk to tropical ecosystems, especially in turbidity-sensitive environments such as coral reefs, filter feeding communities and seagrasses. There is little detailed observational time-series data on the spatial effects of dredging on turbidity and light and defining likely footprints is a fundamental task for impact prediction, the EIA process, and for designing monitoring projects when dredging is underway. It is also important for public perception of risks associated with dredging. Using an extensive collection of in situ water quality data (73 sites) from three recent large scale capital dredging programs in Australia, and which included extensive pre-dredging baseline data, we describe relationships with distance from dredging for a range of water quality metrics. Using a criterion to define a zone of potential impact of where the water quality value exceeds the 80th percentile of the baseline value for turbidity-based metrics or the 20th percentile for the light based metrics, effects were observed predominantly up to three km from dredging, but in one instance up to nearly 20 km. This upper (~20 km) limit was unusual and caused by a local oceanographic feature of consistent unidirectional flow during the project. Water quality loggers were located along the principal axis of this flow (from 200 m to 30 km) and provided the opportunity to develop a matrix of exposure based on running means calculated across multiple time periods (from hours to one month) and distance from the dredging, and summarized across a broad range of percentile values. This information can be used to more formally develop water quality thresholds for benthic organisms, such as corals, filter-feeders (e.g. sponges) and seagrasses in future laboratory- and field-based studies using environmentally realistic and relevant exposure scenarios, that may be used to further refine distance based analyses of impact, potentially further reducing the size of the dredging

Spatial Patterns in Water Quality Changes during Dredging in Tropical Environments.

PubMed

Fisher, Rebecca; Stark, Clair; Ridd, Peter; Jones, Ross

2015-01-01

Dredging poses a potential risk to tropical ecosystems, especially in turbidity-sensitive environments such as coral reefs, filter feeding communities and seagrasses. There is little detailed observational time-series data on the spatial effects of dredging on turbidity and light and defining likely footprints is a fundamental task for impact prediction, the EIA process, and for designing monitoring projects when dredging is underway. It is also important for public perception of risks associated with dredging. Using an extensive collection of in situ water quality data (73 sites) from three recent large scale capital dredging programs in Australia, and which included extensive pre-dredging baseline data, we describe relationships with distance from dredging for a range of water quality metrics. Using a criterion to define a zone of potential impact of where the water quality value exceeds the 80th percentile of the baseline value for turbidity-based metrics or the 20th percentile for the light based metrics, effects were observed predominantly up to three km from dredging, but in one instance up to nearly 20 km. This upper (~20 km) limit was unusual and caused by a local oceanographic feature of consistent unidirectional flow during the project. Water quality loggers were located along the principal axis of this flow (from 200 m to 30 km) and provided the opportunity to develop a matrix of exposure based on running means calculated across multiple time periods (from hours to one month) and distance from the dredging, and summarized across a broad range of percentile values. This information can be used to more formally develop water quality thresholds for benthic organisms, such as corals, filter-feeders (e.g. sponges) and seagrasses in future laboratory- and field-based studies using environmentally realistic and relevant exposure scenarios, that may be used to further refine distance based analyses of impact, potentially further reducing the size of the dredging

Late Pliocene Depositional History and Paleoclimate Reconstructions of the Southwest Pacific

NASA Astrophysics Data System (ADS)

Royce, B.; Patterson, M. O.; Pietras, J.

2017-12-01

Drift deposits off the eastern margin of New Zealand are important archives for the paleoclimate and paleoceanographic history of the southwest Pacific. Ocean Drilling Program (ODP) Site 1123 is located on the North Chatham rise drift just North of the westerly wind driven Subtropical Front (STF) and provides a record of near continuous sediment deposition since the Miocene along the southwest Pacific deep western boundary current (DWBC). While the Miocene and Late Pleistocene portion of this record have been well studied, the Late Pliocene record is less well developed. Southern Ocean geological records demonstrate that Late Pliocene cooling is the transient time bracketing the warmer than present Early Pliocene and bipolar glaciation at 2.7 Ma. A newly developed, robust, and astronomically tuned long-term record of benthic δ13C from ODP Site 1123 spanning the Early to Late Pliocene implies a reduction in Southern Ocean ventilation and lowering of preformed values from waters sourced along the Antarctic margin during the Late Pliocene. Thus, Late Pliocene Southern Hemisphere cooling and sea ice expansion may have drastically reduced outgassing and increased the burial of heat into the deep ocean. South Atlantic records off the west coast of Africa demonstrate an increase in the flux of iron to the open ocean during this time potentially enhancing surface ocean productivity and providing an additional cooling mechanism. Currently, atmospheric transport of dust to the Southern Ocean is dominated by persistent mid-latitude circumpolar westerly winds; this is particularly relevant for dust sourced from New Zealand. The Late Pliocene to Early Pleistocene uplift of the North Island axial ranges and South Island southern alps potentially provided a greater amount of not only sediment to the deep ocean, but also wind blow dust to the Pacific sector of the Southern Ocean. We will present a detailed high-resolution sedimentological study on the development of the Chatham

Study of Morphologic Change in Poyang Lake Basin Caused by Sand Dredging Using Multi-temporal Landsat Images and DEMs

NASA Astrophysics Data System (ADS)

Qi, S.; Zhang, X.; Wang, D.; Zhu, J.; Fang, C.

2014-11-01

Sand dredging has been practiced in rivers, lakes, harbours and coastal areas in recent years in China mostly because of demand from construction industry as building material. Sand dredging has disturbed aquatic ecosystems by affecting hydrological processes, increasing content of suspended sediments and reducing water clarity. Poyang Lake, connecting with Yangtze River in the lower reaches of the Yangtze River, is the largest fresh water lake in China. Sand dredging in Poyang Lake has been intensified since 2001 because such practice was banned in Yangtze River and profitable. In this study, the morphologic change caused by sand dredging in Poyang Lake basin was analysed by overlaying two DEMs acquired in 1952 and 2010 respectively. Since the reflectance of middle infrared band for sand dredging vessel is much higher than that of water surface, sand dredging vessels were showed as isolated grey points and can be counted in the middle infrared band in 12 Landsat images acquired in flooding season during 2000~2010. Another two Landsat images (with low water level before 2000 and after 2010) were used to evaluate the morphologic change by comparing inundation extent and shoreline shape. The following results was obtained: (1) vessels for sand dredging are mainly distributed in the north of Poyang Lake before 2007, but the dredging area was enlarged to the central region and even to Gan River; (2) sand dredging area reached to about 260.4 km2 and is mainly distributed in the north of Songmen Mountain and has been enlarged to central of Poyang Lake from the distribution of sand vessels since 2007. Sand dredged from Poyang Lake was about 1.99 × 109 m3 or 2448 Mt assuming sediment bulk density of 1.23 t m-3. It means that the magnitude of sand mining during 2001-2010 is almost ten times of sand depositions in Poyang Lake during 1955-2010; (3) Sand dredging in Poyang Lake has alternated the lake capacity and discharge section area, some of the watercourse in the

Morphological Response of a Mud Capped Dredge Pit in Western Louisiana After Sand Excavation for Barrier Island Restoration

NASA Astrophysics Data System (ADS)

Robichaux, P. A.; Xu, K.; Bentley, S. J.; Li, C.; Miner, M. D.

2017-12-01

Sand resources play a crucial role in supporting tourism, maintaining coastal ecosystems, and protecting property and infrastructure. Mud capped dredge pits (MCDPs) are created when paleochannel sand, covered by muddy shelf overburden, is excavated for restoration purposes; such paleochannels are one significant sand resource for coastal barrier protection. However, our knowledge of MCDPs is limited. To improve understanding of their morphological behavior, a dredge pit called Peveto Channel (PC) offshore of Holly Beach, LA, was studied in 2016. Our study consisted of a survey using multiple geophysical methods, including multibeam bathymetry, sidescan sonar, subbottom profiling, and magnetometry. Results indicate that PC has undergone 100% infilling since dredging occurred. Although the pit is filled up, analyses indicate the newly deposited material is unconsolidated and has yet to equilibrate to the ambient seafloor conditions. The surface of the pit area is pockmarked and uneven, likely caused by degassing processes and differential consolidation. Sidescan sonar images confirm that the pit walls have experienced little to no lateral erosion and are well preserved. The results from this survey and from historical surveys conducted in 2003 (a few months after dredging), 2004, 2006, and 2007 are compared to previously constructed numerical models used to predict the behavior of dredge pits. To our knowledge, PC is the only filled-up offshore dredge pit in coastal Louisiana. Thus the findings of this study provide new long-term information for regulatory policies and the feasibility of MCDPs as sand resources in the future.

Dredging displaces bottlenose dolphins from an urbanised foraging patch.

PubMed

Pirotta, Enrico; Laesser, Barbara Eva; Hardaker, Andrea; Riddoch, Nicholas; Marcoux, Marianne; Lusseau, David

2013-09-15

The exponential growth of the human population and its increasing industrial development often involve large scale modifications of the environment. In the marine context, coastal urbanisation and harbour expansion to accommodate the rising levels of shipping and offshore energy exploitation require dredging to modify the shoreline and sea floor. While the consequences of dredging on invertebrates and fish are relatively well documented, no study has robustly tested the effects on large marine vertebrates. We monitored the attendance of common bottlenose dolphins (Tursiops truncatus) to a recently established urbanised foraging patch, Aberdeen harbour (Scotland), and modelled the effect of dredging operations on site usage. We found that higher intensities of dredging caused the dolphins to spend less time in the harbour, despite high baseline levels of disturbance and the importance of the area as a foraging patch. Copyright © 2013 Elsevier Ltd. All rights reserved.

[Effects of sediment dredging on benthos community structure and water quality in Zhushan Bay].

PubMed

Liu, Guo-Feng; Zhang, Zhi-Yong; Liu, Hai-Qin; Zhong, Ji-Cheng; Yan, Shao-Hua; Fan, Cheng-Xin

2010-11-01

We surveyed the changes of macro-benthos community composition and nutrients concentration in water in Zhushan Bay after it had been dredged 6 months, which aimed to remove the polluted surface sediments. The results showed that the main benthos in the dredged and un-dredged sediments were Limodrilus hoffmeisteri, Pelopia and Bellamya aeruginosa; compared to the un-dredged sediments, the bio-diversity of dredged areas became lower. However, its biomass became higher than that in un-dredged areas. Concentration range changes of TN and TP in overlying water was 1.64-4.45 mg/L and 0.133-0.258 mg/L, respectively. The post-dredged sediments were still in a higher state of nutrients for the higher concentration nutrients in overlying water, macro-benthos were the species that lived in a serious polluted water environment. Using Shannon-Weaver, Simpson, and Goodnight benthic index to evaluate the results show that the dredged area is in the moderately polluted level, but un-dredged area is in the middle-heavily polluted level. According to the benthos fauna surveys and water quality monitoring results, the effective of sediment dredging could play its role only the strict control on the external pollution resources have been made and reduces the effects of polluted water on the sediments.

Deep-tow geophysical survey above large exhumed mantle domains of the eastern Southwest Indian ridge

NASA Astrophysics Data System (ADS)

Bronner, A.; Munschy, M.; Sauter, D.; Carlut, J.; Searle, R.; Cannat, M.

2012-04-01

The recent discovery of a new type of seafloor, the "smooth seafloor", formed with no or very little volcanic activity along the easternmost part of the ultra-slow spreading Southwest Indian ridge (SWIR) shows an unexpected complexity in processes of generation of the oceanic lithosphere. There, detachment faulting is thought to be a mechanism for efficient exhumation of deep-seated mantle rocks. We present here a deep-tow geological-geophysical survey over smooth seafloor at the eastern SWIR (62-64°N) combining multibeam bathymetric data, magnetic data, geology mapping from sidescan sonar (TOBI) images and results from dredge sampling. We introduce a new type of calibration approach for deep-tow fluxgate magnetometer. We show that magnetic data can be corrected from the magnetic effect of the vehicle with no recourse to its attitude (pitch, roll and heading) but only using the 3 components recorded by the magnetometer and an approximation of the scalar intensity of the Earth magnetic field. The collected dredge samples as well as the sidescan sonar images confirm the presence of large areas of exhumed mantle-derived peridodites surrounded by a few volcanic constructions. We investigate the possibility that magnetic anomalies are either caused by serpentinized peridotites and/or magmatic intrusions. We show that the magnetic signature of the smooth seafloor is clearly weaker than the surrounding volcanic areas. Moreover, the calculated magnetization of a source layer as well as the comparison between deep-tow and sea-surface magnetic data argue for strong East-West variability in the distribution of the magnetized sources. This variability may result from fluid-rock interactions along the detachment faults as well as from the occurrence of small sized and thin volcanic patches and thus questions the seafloor spreading origin of the corresponding magnetic anomalies. Finally, we provide magnetic arguments, as calculation of block rotation or spreading asymmetry in

Risk-based decision-making framework for the selection of sediment dredging option.

PubMed

Manap, Norpadzlihatun; Voulvoulis, Nikolaos

2014-10-15

The aim of this study was to develop a risk-based decision-making framework for the selection of sediment dredging option. Descriptions using case studies of the newly integrated, holistic and staged framework were followed. The first stage utilized the historical dredging monitoring data and the contamination level in media data into Ecological Risk Assessment phases, which have been altered for benefits in cost, time and simplicity. How Multi-Criteria Decision Analysis (MCDA) can be used to analyze and prioritize dredging areas based on environmental, socio-economic and managerial criteria was described for the next stage. The results from MCDA will be integrated into Ecological Risk Assessment to characterize the degree of contamination in the prioritized areas. The last stage was later described using these findings and analyzed using MCDA, in order to identify the best sediment dredging option, accounting for the economic, environmental and technical aspects of dredging, which is beneficial for dredging and sediment management industries. Copyright © 2014 Elsevier B.V. All rights reserved.

Platform of integrated tools to support environmental studies and management of dredging activities.

PubMed

Feola, Alessandra; Lisi, Iolanda; Salmeri, Andrea; Venti, Francesco; Pedroncini, Andrea; Gabellini, Massimo; Romano, Elena

2016-01-15

Dredging activities can cause environmental impacts due to, among other, the increase of the Suspended Solid Concentration (SSC) and their subsequent dispersion and deposition (DEP) far from the dredging point. The dynamics of the resulting dredging plume can strongly differ in spatial and temporal evolution. This evolution, for both conventional mechanical and hydraulic dredges, depends on the different mechanisms of sediment release in water column and the site-specific environmental conditions. Several numerical models are currently in use to simulate the dredging plume dynamics. Model results can be analysed to study dispersion and advection processes at different depths and distances from the dredging source. Usually, scenarios with frequent and extreme meteomarine conditions are chosen and extreme values of parameters (i.e. maximum intensity or total duration) are evaluated for environmental assessment. This paper presents a flexible, consistent and integrated methodological approach. Statistical parameters and indexes are derived from the analysis of SSC and DEP simulated time-series to numerically estimate their spatial (vertical and horizontal) and seasonal variability, thereby allowing a comparison of the effects of hydraulic and mechanical dredges. Events that exceed defined thresholds are described in term of magnitude, duration and frequency. A new integrated index combining these parameters, SSCnum, is proposed for environmental assessment. Maps representing the proposed parameters allow direct comparison of effects due to different (mechanical and hydraulic) dredges at progressive distances from the dredging zone. Results can contribute towards identification and assessment of the potential environmental effects of a proposed dredging project. A suitable evaluation of alternative technical choices, appropriate mitigation, management and monitoring measure is allowed in this framework. Environmental Risk Assessment and Decision Support Systems (DSS

Rare earth abundances and Rb-Sr systematics of basalts, gabbro, anorthosite and minor granitic rocks from the Indian Ocean Ridge System, Western Indian Ocean

USGS Publications Warehouse

Hedge, C.E.; Futa, K.; Engel, C.G.; Fisher, R.L.

1979-01-01

Basalts dredged from the Mid-Indian Ocean Ridge System have rare earth, Rb, and Sr concentrations like those from other mid-ocean ridges, but have slightly higher Sr87/Sr86 ratios. Underlying gabbroic complexes are similar to the basalts in Sr87/Sr86, but are poorer K, Rb, and in rare earths. The chemical and isotopic data, as well as the geologic relations suggest a cumulate origin for the bulk of the gabbroic complexes. ?? 1979 Springer-Verlag.

[Startup mechanism of moxibustion warming and dredging function].

PubMed

Huang, Kaiyu; Liang, Shuang; Sun, Zheng; Zhang, Jianbin

2017-09-12

With "moxibustion" and "warm stimulation" as the keywords, the literature on moxibustion mechanism of warming and dredging from June 1st, 1995 to June 1st, 2016 was collected from PubMed, China National Knowledge Infrastructure (CNKI) and Wanfang database. The startup mechanism of moxibustion warming and dredging function was analyzed in terms of moxibustion warming stimulation. The results were found that moxibustion was based on local rising temperature of acupoint. It activated local specific receptors, heat sensitive immune cells, heat shock proteins and so on to start the warming and dredging function and produce various local effects. The warming stimulation signals as well as subsequent effects through nerve and body fluid pathways induced the effects of further specific target organs and body systems.

Assessing the impacts of sediments from dredging on corals.

PubMed

Jones, Ross; Bessell-Browne, Pia; Fisher, Rebecca; Klonowski, Wojciech; Slivkoff, Matthew

2016-01-15

There is a need to develop water quality thresholds for dredging near coral reefs that can relate physical pressures to biological responses and define exposure conditions above which effects could occur. Water quality characteristics during dredging have, however, not been well described. Using information from several major dredging projects, we describe sediment particle sizes in the water column/seabed, suspended sediment concentrations at different temporal scales during natural and dredging-related turbidity events, and changes in light quantity/quality underneath plumes. These conditions differ considerably from those used in past laboratory studies of the effects of sediments on corals. The review also discusses other problems associated with using information from past studies for developing thresholds such as the existence of multiple different and inter-connected cause-effect pathways (which can confuse/confound interpretations), the use of sediment proxies, and the reliance on information from sediment traps to justify exposure regimes in sedimentation experiments. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

Impact of pozzolanic binder addition on stabilization of polluted dredged sediments on its potential reuse as a new material resource for road construction in Basse Normandie, France

NASA Astrophysics Data System (ADS)

Silitonga, E.

2018-02-01

Due to the increase of the amount of marine dredged sediments (MDS) and the cost of managing the disposal site is very high, a reutilization of dredged sediment is urgently needed in France. The primary goal of this research is to find a domain for reuse of MDS materials as a new material regarding the environmental issues, and other requirement needed. In this study, the MDS was used as replacement material in road construction. Hence, various tests need to be realized to identify if MDS could achieve the requirement needed in this domain. The secondary objective is to enhance the geotechnical characteristic and to reduce the pollution content of the MDS, by incorporating binders and sediments, and revealed the geotechnical characteristic. The geotechnical test result shows that the stabilization by hydraulics binders improve the geotechnical characteristic and could fulfil the requirement needed. The present of Fly Ash and Silica Fume in this study is aimed to reduce the pollution level, especially the heavy metal content. After the geotechnical study in laboratory results shows as expected then the study to identify the chemical characteristic was realized. In order to evaluate the environmental impacts, leaching test was performed. The Leaching test result shows that with 7% of Silica Fume and 10% of Fly Ash capable to fulfil the criteria needed, hence, the use of MDS is consider safe in term of geotechnical and environmental impact, as a new material in road construction

Melt extraction and mantle source at a Southwest Indian Ridge Dragon Bone amagmatic segment on the Marion Rise

NASA Astrophysics Data System (ADS)

Gao, Changgui; Dick, Henry J. B.; Liu, Yang; Zhou, Huaiyang

2016-03-01

This paper works on the trace and major element compositions of spatially associated basalts and peridotites from the Dragon Bone amagmatic ridge segment at the eastern flank of the Marion Platform on the ultraslow spreading Southwest Indian Ridge. The rare earth element compositions of basalts do not match the pre-alteration Dragon Bone peridotite compositions, but can be modeled by about 5 to 10% non-modal batch equilibrium melting from a DMM source. The Dragon Bone peridotites are clinopyroxene-poor harzburgite with average spinel Cr# 27.7. The spinel Cr# indicates a moderate degree of melting. However, CaO and Al2O3 of the peridotites are lower than other abyssal peridotites at the same Mg# and extent of melting. This requires a pyroxene-poor initial mantle source composition compared to either hypothetical primitive upper mantle or depleted MORB mantle sources. We suggest a hydrous melting of the initial Dragon Bone mantle source, as wet melting depletes pyroxene faster than dry. According to the rare earth element patterns, the Dragon Bone peridotites are divided into two groups. Heavy REE in Group 1 are extremely fractionated from middle REE, which can be modeled by 7% fractional melting in the garnet stability field and another 12.5 to 13.5% in the spinel stability field from depleted and primitive upper mantle sources, respectively. Heavy REE in Group 2 are slightly fractionated from middle REE, which can be modeled by 15 to 20% fractional melting in the spinel stability field from a depleted mantle source. Both groups show similar melting degree to other abyssal peridotites. If all the melt extraction occurred at the middle oceanic ridge where the peridotites were dredged, a normal 6 km thick oceanic crust is expected at the Dragon Bone segment. However, the Dragon Bone peridotites are exposed in an amagmatic ridge segment where only scattered pillow basalts lie on a partially serpentinized mantle pavement. Thus their depletion requires an earlier melting

Unraveling the unusual morphology of the Cretaceous Dirck Hartog extinct mid-ocean ridge

NASA Astrophysics Data System (ADS)

Watson, S. J.; Whittaker, J. M.; Halpin, J.; Williams, S.; Milan, L. A.; Daczko, N. R.; Wyman, D. A.

2015-12-01

The Perth Abyssal Plain (PAP), offshore southwest Australia formed during Mesozoic East Gondwana breakup and Kerguelen plume activity. This study combines petrographic and geochemical data from the first samples ever to be dredged from the flanks of the Dirck Hartog Ridge (DHR), a prominent linear bathymetric feature in the central PAP, with new bathymetric profiles across the PAP to better constrain the formation of the early Indian Ocean floor. The DHR exhibits high relief and distinctive asymmetry that is unusual compared to most active or extinct spreading centres and likely results from compression and deformation of the recently extinct DHR during changes in relative motion of the Indian plate (110 - 100 Ma). Exhumation of gabbros in the southern DHR and an increase in seafloor roughness towards the centre of the PAP, likely result from a half spreading rate decrease from 35 mm/yr (based on magnetic reversals) to 24 mm/yr at ~114 Ma. The results support a slowdown of spreading prior to full cessation at ~102 Ma. The composition of basaltic samples varies along the DHR: from sub-alkaline dolerites with incompatible element concentrations most similar to depleted-to-normal mid-ocean ridge basalts in the south, to alkali basalts similar to ocean island basalts in the north. Therefore, magma sources and degrees of partial melting varied in space and time, a result supporting the interpretation that the DHR is an extinct spreading ridge rather than a pseudofault. The enriched alkali basalt signatures may be attributed to melting of a heterogeneous mantle or to the influence of the Kerguelen plume over distances greater than 1000 km. The results demonstrate the significance of regional tectonic plate motions on the formation and deformation of young ocean crust, and provide insight into the unique DHR morphology.

The Surface Microlayer: Review of Literature and Evaluation of Potential Effects of Dredge Activities in Puget Sound.

DTIC Science & Technology

1987-01-01

Heyrand. 1975. Polonium - 210 - Its vertical oceanic transport by zoo- plankton metabolic activity. Marine Chemistry 3:105-110. Collins, J. 1974. Oil and...Toxicology Environ. Health 7:991-1000. Hose, J.E., J.B. Hannah, D. Dijulio, M.L. Landolt, B.S. Miller, W.T. Iwaoka, and S.P. Felton. 1982. Effects of benzo(a...A184 885 THE SURFACE MICROLAVER, REVIEWJ OF LITERATURE AND 1/2 EVALUATION OF POTENTIAL EFFECTS OF DREDGE ACTIVITIES IN PUGET SOUND(U) EVANS-HAMILTON

Methods and Metrics for Evaluating Environmental Dredging ...

EPA Pesticide Factsheets

This report documents the objectives, approach, methodologies, results, and interpretation of a collaborative research study conducted by the National Risk Management Research Laboratory (NRMRL) and the National Exposure Research laboratory (NERL) of the U.S. Environmental Protection Agency’s (U.S. EPA’s) Office of Research and Development (ORD) and the U.S. EPA’s Great Lakes National Program Office (GLNPO). The objectives of the research study were to: 1) evaluate remedy effectiveness of environmental dredging as applied to contaminated sediments in the Ashtabula River in northeastern Ohio, and 2) monitor the recovery of the surrounding ecosystem. The project was carried out over 6 years from 2006 through 2011 and consisted of the development and evaluation of methods and approaches to assess river and ecosystem conditions prior to dredging (2006), during dredging (2006 and 2007), and following dredging, both short term (2008) and long term (2009-2011). This project report summarizes and interprets the results of this 6-year study to develop and assess methods for monitoring pollutant fate and transport and ecosystem recovery through the use of biological, chemical, and physical lines of evidence (LOEs) such as: 1) comprehensive sampling of and chemical analysis of contaminants in surface, suspended, and historic sediments; 2) extensive grab and multi-level real time water sampling and analysis of contaminants in the water column; 3) sampling, chemi

Strength characteristics of lightly solidified dredged marine clay admixed with bentonite

NASA Astrophysics Data System (ADS)

Ariffin, Syazwana Tajul; Chan, Chee-Ming

2017-11-01

Strength characteristic is a significant parameter in measuring the effect of soil improvement and effective composition of solidification. In this study, the dredged marine sediment (DMS) collected from Kuala Perlis (Malaysia) was examined to determine its strength characteristics under light cement solidification with bentonite. Dredged marine clay generally has the low shear strength and high void ratio, and consists mainly of soil particles of the fine-grained type. As a discarded geo-waste, it can be potentially treated to for reuse as a backfill material instead of being disposed of, hence reducing the negative impact on the environment. Physico-chemical parameters of the dredged sample were first determined, then solidification was carried out to improve the engineering properties by admixing ordinary Portland cement (OPC) as the binder and bentonite as a volume enhancer to the soil. The DMS was treated with the addition of 3 % and 6 % cement and bentonite within the range of 0-30 %. The specimens were cured at room temperature for 3, 7 and 14 days. The strength gain was measured by unconfined compression test and vane shear test. The laboratory test results were analyzed to establish the relationship between strength properties and solidification specifications. In summary, the strength of specimens increased with the increase of the quantity of bentonite and cement to get the effective composition of the specimen.

76 FR 11961 - Safety Zone, Dredging Operations; Delaware River, Marcus Hook, PA

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-04

...-AA00 Safety Zone, Dredging Operations; Delaware River, Marcus Hook, PA AGENCY: Coast Guard, DHS. ACTION... Delaware River while the Dredge Pullen conducts dredging operations at the Sunoco Marcus Hook docks in the vicinity of the Marcus Hook Range near Marcus Hook, PA. This action is necessary to maintain the 42 ft...

77 FR 47284 - Safety Zone; Dredge Arthur J, Lake Huron, Lakeport, MI

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-08

...-AA00 Safety Zone; Dredge Arthur J, Lake Huron, Lakeport, MI AGENCY: Coast Guard, DHS. ACTION: Temporary... preparation for and salvage operations of the Arthur J. dredge vessel. This temporary safety zone is necessary... sinking of the dredge vessel Arthur J. precluded the Coast Guard from having sufficient time to publish an...

Sedimentation patterns caused by scallop dredging in a physically dynamic environment.

PubMed

Dale, A C; Boulcott, P; Sherwin, T J

2011-11-01

Scallop dredging grounds in the Firth of Lorn, western Scotland, are juxtaposed with rocky reef habitats raising concerns that reef communities may be impacted by sediment disturbed by nearby scallop dredging. A particle-tracking model of sediment transport and settling is applied at two scales. In the near-field, a suspension of typical sand/gravel-dominated bed sediment is subjected to a steady current across the dredge track. In the far-field, silt particles, which may persist in suspension for multiple tidal cycles, are tracked in the context of a regional model of tidally-driven flow. The principal sedimentary risk to reef habitats is predicted to come from settling sand particles when dredge tracks approach within tens of metres of a reef. The cumulative effect of dredging at the relatively low intensities recorded in this region is not expected to have a significant long-term impact on suspended silt concentrations and settlement in this highly dispersive environment. Copyright © 2011 Elsevier Ltd. All rights reserved.

Processes affecting the spatial distribution of seagrass meadow sedimentary material on Yao Yai Island, Thailand

NASA Astrophysics Data System (ADS)

Quak, Michelle S. Y.; Ziegler, Alan D.; Benner, Shawn G.; Evans, Sam; Todd, Peter A.; Gillis, Lucy G.; Vongtanaboon, Sukanya; Jachowski, Nick; Bouma, Tjeerd J.

2016-12-01

Many islands throughout SE Asia are experiencing rapid development and land-cover conversion that potentially threaten sensitive coastal ecosystems, such as seagrasses, through increased loading of sediment and nutrients originating from disturbed catchments draining to the sea. To evaluate this threat for one such island in Southern Thailand (Yao Yai), we perform sediment source tracing via end-member mixing analysis using stable isotopes δ13C and δ15N in organic matter to explore sediment loading in a seagrass meadow. The analysis indicates that sedimentary material in the meadow originates mostly from ocean-associated sources (∼62% from seagrass detritus, seston, and ocean sediments). Terrestrial material comprises ∼19% of the organic material found in the seagrass meadow, with another 20% originating from an adjacent mangrove forest. Approximately one-fourth of the seagrass meadow material (24%) is detritus that has been (re)deposited internally. The high contribution of terrestrial-derived organic matter deposited near the river mouth demonstrates that substantial quantities of sediment are being transferred from upslope erosion sources into the seagrass meadow. However, only a small amount of this material is deposited throughout the entire bay because much of the terrestrial- and mangrove-derived sediment is transferred to the open ocean via channels that are periodically dredged to allow boat access to two small inland harbours. This positive affect of dredging has not received very much attention in existing literature. River water flowing to the channels during falling tide delivers sediment to these efficient pathways, where much of it bypasses the seagrass meadow at periods of time when sediment deposition would normally be the greatest. There is growing concern that ongoing land-cover changes and planned urbanization related to tourism and agriculture on the island may boost sediment/nutrients above a critical threshold, beyond that revealed in

[Influence of dredging on sediment resuspension and phosphorus transfer in lake: a simulation study].

PubMed

Yu, Ju-Hua; Zhong, Ji-Cheng; Zhang, Yin-Long; Fan, Cheng-Xin; He, Wei; Zhang, Lei; Tang, Zhen-Wu

2012-10-01

A simulated experiment was conducted to investigate the impacts of sediment dredging on sediment resuspension and phosphorus transfer in the summer and winter seasons under the common wind-wave disturbance, and the contaminated sediment used in this study was from Meiliang Bay, Taihu lake. The result showed that 20 cm dredging could effectively inhibit the sediment resuspension in study area, dredging in winter has a better effect than that in summer, and the higher values of the total suspended solid (TSS) in undredged and dredged water column during the process of wind wave disturbance were 7.0 and 2.2, 24.3 and 6.4 times higher than the initial value in summer and winter simulation respectively. The paired-samples t-test result demonstrated that total phosphorus (TP) and phosphate (PO4(3-)-P) loading positively correlated to TSS content in dredged (P<0.01) and undredged water column (P<0.05), which proved that internal phosphorus fulminating release induced by wind-wave disturbance would significantly increase the TP and PO4(3-)-P loading in the water column. The effect of dredging conducted in summer on the TP and PO4(3)-P loading in the water column was negative, but not for winter dredging (P<0.01). The pore water dissolved reactive phosphorus (DRP) profile at water-sediment interface in summer simulation was also investigated by diffusive gradients in thin films (DGT) technique. Diffusion layer of the DRP profile in undredged sediment was wider than that in dredged sediment. However, the DRP diffusion potential in dredged sediment was greater than that in undredged sediment, showing that dredging can effectively reduce the risk of the DRP potential release in dredged pore water, but also would induce the DRP fulminating release in the short time under hydrodynamic action. Generally, dredging was usually deployed during the summer and the autumn. Considering Taihu Lake is a large, shallow, eutrophic lake and the contaminant distribution is spatially

33 CFR 324.1 - General.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Department of the Army (DA) permits to authorize the transportation of dredged material by vessel or other... transportation of dredged material for the purpose of dumping in the ocean waters also require DA permits under... the United States. Applicants for DA permits under this part should also refer to 33 CFR part 322 to...

Life cycle assessment for dredged sediment placement strategies.

PubMed

Bates, Matthew E; Fox-Lent, Cate; Seymour, Linda; Wender, Ben A; Linkov, Igor

2015-04-01

Dredging to maintain navigable waterways is important for supporting trade and economic sustainability. Dredged sediments are removed from the waterways and then must be managed in a way that meets regulatory standards and properly balances management costs and risks. Selection of a best management alternative often results in stakeholder conflict regarding tradeoffs between local environmental impacts associated with less expensive alternatives (e.g., open water placement), more expensive measures that require sediment disposal in constructed facilities far away (e.g., landfills), or beneficial uses that may be perceived as risky (e.g., beach nourishment or island creation). Current sediment-placement decisions often focus on local and immediate environmental effects from the sediment itself, ignoring a variety of distributed and long-term effects from transportation and placement activities. These extended effects have implications for climate change, resource consumption, and environmental and human health, which may be meaningful topics for many stakeholders not currently considered. Life-Cycle Assessment (LCA) provides a systematic and quantitative method for accounting for this wider range of impacts and benefits across all sediment management project stages and time horizons. This paper applies a cradle-to-use LCA to dredged-sediment placement through a comparative analysis of potential upland, open water, and containment-island placement alternatives in the Long Island Sound region of NY/CT. Results suggest that, in cases dealing with uncontaminated sediments, upland placement may be the most environmentally burdensome alternative, per ton-kilometer of placed material, due to the emissions associated with diesel fuel combustion and electricity production and consumption required for the extra handling and transportation. These results can be traded-off with the ecosystem impacts of the sediments themselves in a decision-making framework. Published by

75 FR 5708 - Ocean Dumping; Designation of Ocean Dredged Material Disposal Sites Offshore of the Siuslaw River...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-04

... suspended by wave action near the bottom, and are moved by bottom currents or directly as bedload. Tidal, wind and wave forces contribute to generating bottom currents, which act in relation to the sediment... littoral zone, limit wave effects due to mounding, and keep material from reentering the navigation channel...

Ocean Dredged Material Disposal Site (ODMDS) Authorization and Short-Term FATE (STFATE) Model Analysis: 2014-2015 Working Group Findings Report

DTIC Science & Technology

2016-03-01

Simpson. 2009. Development of guidelines for ammonia in estuarine and marine water systems. Marine Pollution Bulletin 58:1472–1476. Boardman, G. D...waters of the United States and ocean waters is a shared responsibility of the USACE and U.S. Environmental Protection Agency (USEPA) under the Marine ...waters of the United States and ocean waters is a shared responsibility of USEPA and the USACE. The Marine Protection, Research, and Sanctuaries Act

An evaluation of the success of dredging as remediation at a DDT-contaminated site in San Francisco Bay, California, USA.

PubMed

Weston, Donald P; Jarman, Walter M; Cabana, Gilbert; Bacon, Corinne E; Jacobson, Lisa A

2002-10-01

Lauritzen Canal, a portion of San Francisco Bay near Richmond, California, USA, was heavily contaminated with dichlorodiphenyltrichloroethane (DDT) and dieldrin as a result of releases from a pesticide-formulating firm. In 1996 and 1997, 82,000 m3 of contaminated sediment was removed from the canal by dredging. This study evaluated the success of the dredging based largely on body burdens of DDT and its metabolites (sigmaDDT) in resident biota, with some data on sediment- and water-contaminant levels and sediment toxicity testing. Sediment disturbance during dredging introduced a pulse of sigmaDDT into the Lauritzen Canal ecosystem, and body burdens of fish and invertebrates increased 2- to 76-fold, depending on the species. Approximately 1 1/2 years after remediation, 11 of 14 indicators showed contamination comparable with or worse than the contamination that existed prior to dredging. Monitoring of mussels up to four years postdredging suggests some modest improvement, although the sigmaDDT body burden of canal mussels remained far above the norm for San Francisco Bay. The elevated sigmaDDT body burdens in biota that persisted for years after remediation reflect recent exposure and are not merely a result of slow metabolic elimination of the sigmaDDT pulse associated with dredging. Sediment sigmaDDT concentrations were low immediately after dredging, but within months, the canal bottom became covered with a veneer of fine sediment as contaminated as that that had been removed. The source of this material has not been conclusively established, but we suspect it came from slumping and erosion from the flanks of the canal beneath docks and around pilings where dredging was not done. In retrospect, either capping in place or more thorough dredging may have been more successful in reducing pesticide exposure of the biota, although there were difficulties associated with both alternatives.

87Sr/86Sr ratios in basalts from islands in the Indian Ocean

USGS Publications Warehouse

Hedge, C.E.; Watkins, N.D.; Hildreth, R.A.; Doering, W.P.

1973-01-01

87Sr/86Sr ratios of basalts from islands in the Indian Ocean (0.7040) are higher than those of basalts dredged from the Mid-Indian Ocean Ridge (0.7034). The sources of the island basalts have apparently not been in equilibrium with the source of the ridge basalts for roughly 109 years. Both ridge and island basalts in the Indian Ocean are higher in 87Sr/86Sr than are rocks from similar settings in the eastern Pacific. ?? 1973.

Interannual variability in phytoplankton blooms observed in the northwestern Arabian Sea during the southwest monsoon

NASA Technical Reports Server (NTRS)

Brock, John C.; Mcclain, Charles R.

1992-01-01

Interannual changes in the strength and seasonal evolution of the 1979 through 1982 surface-level southwest monsoon winds are related to variations in the summer phytoplankton bloom of the northwestern Arabian Sea by synthesis of satellite ocean-color remote sensing with analysis of in-situ hydrographic and meteorological data sets. The 1979-1981 southwest monsoon phytoplankton blooms in the northwest Arabian Sea peaked during August-September, extended from the Omani coast to about 6 E, and appeared to lag the development of open-sea upwelling by at least 1 month. In all 3 years the bloom was driven by spatially distinct upward nutrient fluxes to the euphotic zone forced by the physical processes of coastal upwelling and offshore Ekman pumping. Coastal upwelling was evident from May through September, yielded the most extreme concentrations of phytoplankton biomass, and along the Omani coast was limited in its impact on upper ocean biological variability to the continental shelf. Ekman pumping stimulated the development of a broad open-ocean component of the southwest monsoon phytoplankton bloom oceanward of the Omani shelf. Phytoplankton biomass on the Omani continental shelf was increased during both the early and late phases of the 1980 southwest monsoon due to stronger coastal upwelling under the most intense southwesterly winds of the four summers investigated. Diminished coastal upwelling during the early phase of the weak 1982 southwest monsoon resulted in a coastal bloom that reached a mean phytoplankton-pigment concentration that was 28 percent of that seen in 1980. The lack of a strong regional northwestern Arabian Sea bloom in late summer 1982 is attributed to the development of persistent, shallow temperature stratification that rendered Ekman pumping less effective in driving upward nutrient fluxes.

21. DREDGING POND USED TO TEST THE ADAPTABILITY OF JET ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

21. DREDGING POND USED TO TEST THE ADAPTABILITY OF JET PUMPS FOR PUMPING SAND, AND WEAR RATES OF DIFFERENT TYPES OF DREDGING PIPE. - Waterways Experiment Station, Hydraulics Laboratory, Halls Ferry Road, 2 miles south of I-20, Vicksburg, Warren County, MS

Collapsed Thunderstorm, Southwest Pacific Ocean

NASA Technical Reports Server (NTRS)

1992-01-01

This collapsed thunderstorm was observed over the open ocean (9.0N, 120.0E) between the Philippine island of Mindoro and Borneo, Malaysia. The cleared area in the center is the result of the clouds being driven from there by the sudden rush of katabatic air spreading downward and outward from the dying thunderstorm. Around the edges of the downdrafted air, new though smaller storms are developing. The two small coral atolls are the Tubbataha Reefs.

A monsoon-like Southwest Australian circulation and its relation with rainfall in Southwest Western Australia

NASA Astrophysics Data System (ADS)

Feng, Juan; Li, Jianping; Li, Yun

2010-05-01

Using the NCEP/NCAR, ERA-40 reanalysis, and precipitation data from CMAP and Australian Bureau of Meteorology, the variability and circulation features influencing the southwest Western Australia (SWWA) winter rainfall are investigated. It is found that the climate of southwest Australia bears a strong seasonality in the annual cycle and exhibits a monsoon-like atmospheric circulation, which is termed as the southwest Australian circulation (SWAC) for its several distinct features characterizing a monsoonal circulation: the seasonal reversal of winds, alternate wet and dry seasons, and an evident land-sea thermal contrast. The seasonal march of the SWAC in extended winter (May to October) is demonstrated by pentad data. An index based on the dynamics normalized seasonality was introduced to describe the behavior and variation of the winter SWAC. It is found that the winter rainfall over SWWA has a significant positive correlation with the SWAC index in both early (May to July) and late (August to October) winter. In weaker winter SWAC years there is an anti-cyclonic anomaly over southern Indian Ocean resulting in weaker westerlies and northerlies which are not favorable for more rainfall over SWWA, and the opposite combination is true in the stronger winter SWAC years. The SWAC explains not only a large portion of the interannual variability of SWWA rainfall in both early and late winter, but also the long term drying trend over SWWA in early winter. The well-coupled SWAC-SWWA rainfall relationship seems to be largely independent of the well-known effects of large-scale atmospheric circulations such as the Southern Hemisphere Annular Mode (SAM), El Niño/Southern Oscillation (ENSO), Indian Ocean Dipole (IOD) and ENSO Modoki (EM). The result offers qualified support for the argument that the monsoon-like circulation may contribute to the rainfall decline in early winter over SWWA.

Investigation of Comparative Mosquito Breeding in Dredged Material Disposal Sites Used in the Maintenance Dredging of the Atlantic Intra-Coastal Waterway in South Carolina.

DTIC Science & Technology

1978-01-01

rctary ditching equipment falls inton thc latter category. Equipment of this type cuts a ditch with a Srt-ating cutting head . As the marsh sod is removed...several years if the site is not further altered by dredging. * 89 W W W V W W W W W W W SITE DESIGNATION: WACCAMAW NECK (G-1O) Summary 151. This...Bionomics and embryology of the inland floodwater mosquito . .. .’. Univ. of Illinois Press. 2 11pp. S Jeane, G. S., II, and R. E. Pine. 1975

Scour of chinook salmon redds on suction dredge tailings

Treesearch

Bret C. Harvey; Thomas E. Lisle

1999-01-01

Abstract - We measured scour of the redds of chinook salmon Oncorhynchus tshawytscha on dredge tailings and natural substrates in three tributaries of the Klamath River, California. We measured maximum scour with scour chains and net scour by surveying before and after high winter flows. Scour of chinook salmon redds located on dredge tailings exceeded scour of redds...

Army Corps of Engineers: Action Needed to Ensure the Quality of Maintenance Dredging Contract Cost Data

DTIC Science & Technology

2015-09-01

planning, awarding, and administering maintenance dredging contracts with industry . 8For more information on hopper dredging, see GAO, Army Corps of...miles of waterways and hundreds of ports of harbors. The Corps conducts maintenance dredging primarily under contract with private industry to...headquarters, divisions, and districts (selected for geographic variation and range of dredging work) and dredging industry stakeholders. What

ENVIRONMENTAL EFFECTS OF DREDGING AND DISPOSAL (E2-D2)

EPA Science Inventory

US Army Corps of Engineers public web site for the "Environmental Effects of Dredging and Disposal" ("E2-D2") searchable database of published reports and studies about environmental impacts associated with dredging and disposal operations. Many of the reports and studies are ava...

Mechanism for generating the anomalous uplift of oceanic core complexes: Atlantis Bank, southwest Indian Ridge

NASA Astrophysics Data System (ADS)

Baines, A. Graham; Cheadle, Michael J.; Dick, Henry J. B.; Hosford Scheirer, Allegra; John, Barbara E.; Kusznir, Nick J.; Matsumoto, Takeshi

2003-12-01

Atlantis Bank is an anomalously uplifted oceanic core complex adjacent to the Atlantis II transform, on the southwest Indian Ridge, that rises >3 km above normal seafloor of the same age. Models of flexural uplift due to detachment faulting can account for ˜1 km of this uplift. Postdetachment normal faults have been observed during submersible dives and on swath bathymetry. Two transform-parallel, large-offset (hundreds of meters) normal faults are identified on the eastern flank of Atlantis Bank, with numerous smaller faults (tens of meters) on the western flank. Flexural uplift associated with this transform-parallel normal faulting is consistent with gravity data and can account for the remaining anomalous uplift of Atlantis Bank. Extension normal to the Atlantis II transform may have occurred during a 12 m.y. period of transtension initiated by a 10° change in spreading direction ca. 19.5 Ma. This extension may have produced the 120-km-long transverse ridge of which Atlantis Bank is a part, and is consistent with stress reorientation about a weak transform fault.

Mechanism for generating the anomalous uplift of oceanic core complexes: Atlantis Bank, southwest Indian Ridge

USGS Publications Warehouse

Baines, A.G.; Cheadle, Michael J.; Dick, H.J.B.; Scheirer, A.H.; John, Barbara E.; Kusznir, N.J.; Matsumoto, T.

2003-01-01

Atlantis Bank is an anomalously uplifted oceanic core complex adjacent to the Atlantis II transform, on the southwest Indian Ridge, that rises >3 km above normal seafloor of the same age. Models of flexural uplift due to detachment faulting can account for ???1 km of this uplift. Postdetachment normal faults have been observed during submersible dives and on swath bathymetry. Two transform-parallel, large-offset (hundreds of meters) normal faults are identified on the eastern flank of Atlantis Bank, with numerous smaller faults (tens of meters) on the western flank. Flexural uplift associated with this transform-parallel normal faulting is consistent with gravity data and can account for the remaining anomalous uplift of Atlantis Bank. Extension normal to the Atlantis II transform may have occurred during a 12 m.y. period of transtension initiated by a 10?? change in spreading direction ca. 19.5 Ma. This extension may have produced the 120-km-long transverse ridge of which Atlantis Bank is a part, and is consistent with stress reorientation about a weak transform fault.

22. VIEW LOOKING FROM FRONT LEFT OF DREDGE TOWARDS GEAR ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

22. VIEW LOOKING FROM FRONT LEFT OF DREDGE TOWARDS GEAR DRIVE OF MAIN (HOISTING) ENGINE. ARM ON RIGHT IS PART OF VALVE LINKAGE. BOX ABOVE THAT IS THE CYLINDER OIL LUBRICATOR. - Dredge CINCINNATI, Docked on Ohio River at foot of Lighthill Street, Pittsburgh, Allegheny County, PA

Early Spring in Europe: A Result of More Dominant North-Atlantic Southwesterlies?

NASA Technical Reports Server (NTRS)

Otterman, J.; Atlas, R.; Chase, T. N.; Chou, S.-H.; Jusem, J. C.; Pielke, R. A., Sr.; Rogers, J.; Russell, G. L.; Schubert, S. D.; Sud, Y. C.;

Environmental Aspects of Dredging: What About Air Quality?

DTIC Science & Technology

2009-01-01

District, IL, 61204, PH (309) 794-5735 ext.6108, FAX: (309) 794-5 5712, email: mark.j.anderson@usace.army.mil 6 2Civil & Environmental Engineering Dept...Michigan Tech University , Houghton, MI 7 49931, PH: (906) 487-1981, FAX: (906) 487-2943, email: barkdoll@mtu.edu 8 9 ABSTRACT 10 Dredging has...the U. S. Army Corps of Engineers (USACE) dredged a total of 26 204.2 million cubic yards (CY) of sediment (NDC 2007). Navigation maintenance 27

Cephalopods of the Southwest Indian OceanRidge: A hotspot of biological diversity and absence of endemism

NASA Astrophysics Data System (ADS)

Laptikhovsky, V.; Boersch-Supan, P.; Bolstad, K.; Kemp, K.; Letessier, T.; Rogers, A. D.

2017-02-01

A total of 68 cephalopod species belonging to 26 families (10-11% of the total known cephalopod diversity) were collected onboard R/V Fridtjof Nansen during a research survey on Southwest Indian Ocean Ridge in November-December 2009. This relatively small area extends from the Tropical front to the Subantarctic front with four distinctive cephalopod faunas and represents one of the most outstanding hotspots of cephalopod diversity reported to date. However, most of the species caught there were characterised by circumglobal distribution in the Southern Hemisphere, and no endemic species were unambiguously found, although a number of taxa could not be confidently attributed to known species. Most of the studied area was dominated by squid species reproducing in epipelagic layers (mostly Enoploteuthidae and Pyroteuthidae). Species reproducing in meso-bathypelagial whose juveniles ascend to surface water (Cranchiidae, Histioteuthidae, etc.) became gradually more and more important southward from the Tropical Zone to the Southern Peripheral Ecotone. In the latter region they were joined by near-bottom dwellers of the order Sepiolida. The epipelagic strategy of reproduction disappears completely at the Subpolar Front, where epipelagic waters were inhabited by young members of the Cranchiidae and Gonatidae hatched in deep-seas. This study demonstrated the importance of conservation and management of this high-seas area, with its unique biodiversity and ecological resources, in line with recommendations by the IUCN Seamount project and Global Ocean Biodiversity Initiative.

Oceanic Influences on North Pacific Storm Track Activity and Southwest United States Precipitation and Streamflow from 1915-2011

NASA Astrophysics Data System (ADS)

Bateman, R.

2016-12-01

The Interdecadal Pacific Oscillation (IPO) and Atlantic Multidecadal Oscillation (AMO) exert influence over the position and strength of storm tracks through ocean interactions with the atmosphere. This study utilizes a comprehensive set of satellite and in situ data from 1915-2011 to show how the IPO and AMO may have influenced and are related to historical cool season storm track activity (STA) over the north Pacific and southwest US (SWUS) precipitation and streamflow. SWUS river basin water supply for people, agriculture and energy production throughout the year is predominantly dependent on snowpack depth and by changes in ocean conditions across multiple time scales. Positive STA, precipitation, and streamflow anomalies are most strongly related to positive (warm) IPO phases across datasets and time periods while negative (cool) IPO phases are more robustly linked to negative precipitation anomalies, especially during the mid-20th century. Sub-basin precipitation is differentially dependent on STA over specific north Pacific regions. Additionally, results show evidence for a small eastward shift in north Pacific STA and a lack in mean poleward movement in historical data. Moreover, the interannual to interdecadal variability discussed in this study will continue to be important to water resource managers throughout the region, regardless of future changes to the mean regional state of the climate.

Laboratory Feasibility Study Concerning the Use of the SediMeter (trademark) to Detect Fine-Scale ( or = 1 mm) Sedimentation Resulting from Dredging Operations

DTIC Science & Technology

2013-07-01

Pages/Services.aspx). As a result of this dredging activity, bottom sediments are stirred up and resuspended into plumes. The transport of these...1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law , no...bed elevation changes as dredged material is pumped into an area such as a wetland. They could also be used to evaluate the geomorphic stability of

Impact of roadside ditch dredging on bacterial communities and biological contamination of a tidal creek

NASA Astrophysics Data System (ADS)

Jones, Chance E.; Barkovskii, Andrei L.

2017-03-01

Tidal creek networks form the primary hydrologic link between estuaries and land-based activities on barrier islands. A possible impact from the excavation of drainage ditch systems on bacterial communities and biological contamination was studied in the water column and sediments of headwater, mid-stream, and mouth sites of the intertidal Oakdale Creek on Sapelo Island, GA. Community analysis was performed using the MiSeq Illumina platform and revealed that dredging was the cause of a significant rise in Proteobacteria, especially γ-proteobacteria. Targeted biological contaminants included fecal indicator bacteria, Enterococcus spp. (Entero-1), pathogens, Shigella spp. (ipaH), and Salmonella spp (invA), virulence associated genes (VG's) of pathogenic E. coli (eaeA, hlyD, stx1, stx2, and set1B), integrons (intI1, intI2), and tetracycline resistance genes (TRGs). Incidence and gene concentrations of Shigella spp., eaeA and set1B, and of TRGs increased 3-20 folds after the onset of dredging, and followed the dredging schedule. Principal Component Analysis suggested possible common carriers for Shigella spp., some TRGs, and the pathogenic E. coli eaeA gene. At the site of dredging, all of the above contaminants were detected at high concentrations. We concluded that excavation of roadside ditches caused significant changes in bacterial composition and a rise in incidence and concentrations of biological contaminants in the creek. The authors suggest a different approach for the maintenance of this material be explored.

Flow and suspended-sand behavior in large rivers after dredging.

NASA Astrophysics Data System (ADS)

Yuill, B. T.; Wang, Y.; Allison, M. A.; Meselhe, E. A.

2017-12-01

Dredging is commonly used in large rivers to promote navigation and provide sediment for engineering projects. Channel bars typically have thicker, coarser sediment deposits than elsewhere on the channel bed and are often the focus of dredging projects. Bar dredging may create deep pits ("borrow pits") that significantly alter flow and sediment transport. Locally, the pit acts as a large bedform, contracting and expanding the flow field and enhancing turbulence. At the reach scale, the pit acts as a new sediment sink and disrupts the sediment budget which may have consequences for channel stability and aquatic ecosystem health. In this study, we focus on the local impact of the borrow pit and how it, similar to dunes, creates a turbulent wake within the downstream flow column. We hypothesize that this wake may have implications for the overlapping suspended-sediment transport fields. Efficient dredging operations requires the ability to predict channel infilling/recovery timescales and in large, sandy rivers, a substantial fraction of the sediment infilling results from the settling of suspended sediment. However, if the turbulent wake significantly alters pathways of sediment settling within the borrow pit, typical models of sediment deposition that do not account for the wake effects may not apply. To explore this problem, we use numerical modelling to predict sand behavior with and without resolving the effects of wake turbulence. Wake turbulence is resolved using detached-eddy simulation and sand settling is simulated using Lagrangian particle tracking. Our study area is a >1 km2 channel bar in the lower Mississippi River, which was dredged in October 2016. We used vessel-based measurements (MBES, ADCP) to characterize the post-dredge hydrodynamic environment. Study results indicate that the turbulent wake significantly impacted suspended-sand behavior as it entered the borrow pit and large eddies increased the vertical grain velocities, mean grain settling was

Numerical Simulation of Magma Effects on Hydrothermal Venting at Ultra-Slow Spreading Southwest Indian Ridge

NASA Astrophysics Data System (ADS)

Zang, Hong; Niu, Xiongwei; Ruan, Aiguo; Li, Jiabiao; Meng, Lin

2017-04-01

Finite element method is used to numerically simulate oceanic crust thermal dynamics in order to understand the hydrothermal venting mechanism at ultra-slow spreading ridge, whether is the ancient magma chamber still living and supplying hot magma for vents or have surrounding hotspots been affecting on the ridge continually with melting and hot magma. Two models are simulated, one is a horizontal layered oceanic crust model and the other is a model derived from wide angle seismic experiment of OBS at the ultra-slow spreading Southwest Indian Ridge (50°E, Zhao et al., 2013; Li et al., 2015; Niu et al., 2015). For the former two cases are simulated: without magma from upper mantel or with continuous magma supply, and for the latter supposing magma supply occurs only once in short period. The main conclusions are as follows: (1) Without melt magma supply at the oceanic crust bottom, a magma chamber can live only thousands ten thousand years. According to the simulated results in this case, the magma chamber revealed by seismic data at the mid-east shallow section of the Southwest Indian Ridge could only last 0.8Ma, the present hydrothermal venting is impossible to be the caused by the magma activity occurred during 8-11Ma (Sauter et al., 2009). (2) The magma chamber can live long time with continuous hot magma supply beneath the oceanic crust due to the melting effects of surrounding ridge hotspots, and would result hydrothermal venting with some tectonic structures condition such as detachment faults. We suggest that the present hydrothermal activities at the mid-east shallow section of the Southwest Indian Ridge are the results of melting effects or magma supply from surrounding hotspots. This research was granted by the National Basic Research program of China (grant 2012CB417301) and the National Natural Science Foundation of China (grants 41176046, 91228205). References Zhao, M., Qiu, X., Li, J., et al., 2013. Three-dimensional seismic structure of the Dragon

Geochemical Characteristics of Granitoids in southwest Tianshan: Four Stages for Geodynamic Evolution of the Southwest Tianshan Orogenic Belt

NASA Astrophysics Data System (ADS)

Zhu, Y.

2016-12-01

Paleozoic intrusive rocks widely exposed in the west Tianshan orogenic belt provides key to understand the geodynamic evolution of the central Asian orogenic belt. A synthesis involving the data for Chinese Yili-central Tianshan and southwest Tianshan and comparison of Kyrgyz Tianshan with a broader dataset including zircon U-Pb ages, zircon Hf isotopic composition, major and trace elements for Paleozoic intrusions are presented to classify the Paleozoic intrusive rocks in four categories which corresponding to subduction of the Terskey Ocean, initial subduction stage of South Tianshan Ocean (STO), major subduction stage of the STO, and collisional to post-collisional stages. The subduction of the Terskey Oceanic crust finally caused the closure of the Terskey Ocean and the opening of the South Tianshan back-arc basin. The development of the Southwest Tianshan back-arc basin formed the STO, which subducted under the Yili-central Tianshan during early Silurian to early Carboniferous, and consequently formed huge arc magmatic rocks. Both the Silurian and early Carboniferous intrusions showing arc geochemical characteristics were derived from partial melting of juvenile arc-derived rocks with involvement of old continental crust. The STO finally closed by the end of early Carboniferous. Afterwards, geodynamic setting changed from convergence to extensional during late Carboniferous to early Permian periods. There is a significant geodynamic change from convergence to extension during late Carboniferous to early Permian, which may be resulted from breakoff of the subducted slab (Fig. 1). Such processes caused upwelling of asthenosphere and triggered partial melting of continental crust, as evidenced by emplacement of voluminous granitic rocks. References: An F, et al, 2013. Journal of Asian Earth Sciences, 78: 100-113; Zhu YF, 2011. Ore Geology Reviews, 40: 108-121; Zhu YF, et al, 2009. Geological Society, London, 166: 1085-1099; Zhu YF et al, 2016. Journal of Earth

Subsolidus cooling of mid-ocean ridge peridotites and implications for the oxygen fugacity of the oceanic upper mantle

NASA Astrophysics Data System (ADS)

Birner, S.; Davis, F. A.; Cottrell, E.; Warren, J. M.; Kelley, K. A.

2017-12-01

Peridotites dredged from mid-ocean ridges provide a window into the chemistry of Earth's upper mantle. At equilibrium, mineral assemblages within peridotite record intrinsic properties, including oxygen fugacity (fO2). During cooling below the solidus, however, reactions affect the chemical compositions and modal abundances of minerals, directly affecting the fO2 recorded by these mineral assemblages. The slow kinetics of subsolidus diffusion also prevent full re-equilibration of peridotite during cooling, and different reactions have different closure temperatures. As a result, peridotites measured at the surface record neither equilibrium nor asthenospheric conditions. In order to quantify the effect of subsolidus diffusion on fO2, we analyzed minerals from abyssal peridotites dredged from the Southwest Indian Ridge (SWIR), which we then used as a basis for modeling potential subsolidus reactions. We first examined exchange reactions where no modal changes occur. We considered both Fe-Mg exchange between olivine and spinel [1] and Al-Cr exchange between orthopyroxene and spinel [2], and combined these models with spinel oxybarometry [3] to determine the effect of these reactions on fO2. Our results indicate that as peridotites cool from 1300°C to 900°C, these exchange processes together increase recorded fO2 by 0.3 log units relative to the approach in which compositional changes are not considered. Some reactions additionally change mineral modal abundances during cooling, in particular the Tschermak exchange in orthopyroxene [2], which consumes olivine and Al-rich orthopyroxene and produces spinel and Al-poor orthopyroxene as temperature decreases. Depending on partitioning of Fe3+ between phases, this reaction may dilute the concentration of Fe3+ in spinel and decrease recorded fO2 as temperature decreases. Preliminary results suggest that the magnitude of this effect is strongly sensitive to both initial spinel mode and partitioning of Fe3+ between

Regional variation in bycatches associated with king scallop (Pecten maximus L.) dredge fisheries.

PubMed

Szostek, Claire L; Murray, Lee G; Bell, Ewen; Lambert, Gwladys; Kaiser, Michel J

2017-02-01

The biomass and composition of bycatch from king scallop dredge fisheries was assessed and compared between the English Channel, Cardigan Bay in Wales and around the Isle of Man. Bycatch composition varied significantly at localised, and broad, geographic scales. The mean proportion of scallop dredge bycatch biomass in the English Channel was 19% of total catch biomass. The proportion of bycatch was lower in Cardigan Bay (15%) but notably higher around the Isle of Man (53%). The proportion of individual bycatch species in dredge catches were low, therefore scallop dredging is unlikely to cause a substantial increase the population mortality of individual commercially fished species beyond that caused by the target fisheries for those species, or bycatches of other fisheries. The amount and mortality of organisms left on the seabed in the dredge path was not quantified in this study but should also be considered in management of the fishery. The discard rate of finfish and shellfish of commercial value from the king scallop dredge fishery in the English Channel was between 18 and 100%, with a higher rate of discarding occurring in the eastern English Channel compared to the west. The clear regional differences in bycatch composition and variation in the quantity of discards mean that an area by area approach to managing bycatch species is required in relation to the king scallop dredge fishery. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

Geotechnical Factors in the Dredgeability of Sediments. Report 1. Geotechnical Descriptors for Sediments to be Dredged

DTIC Science & Technology

1993-11-01

objectives of the work unit. executing dredging projects. The disparities increase risk factors and thus the cost of such SUMMARY: The study identified the...geologists, environmental engineers, biologists, estimators, dredging equipment manufacturers, and dredging contractor personnel have methods for...changed dramatically. A major increase has occurred in the level of contract dredging. Environmental concerns, the consequences of the oil embargo of

44. Photocopied August 1978. DREDGES WORKING AT POWER HOUSE LOCATION, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

44. Photocopied August 1978. DREDGES WORKING AT POWER HOUSE LOCATION, DECEMBER 10, 1898. BY SPECIAL AGREEMENT, CONTRACTORS MASON & HODGE WERE PERMITTED TO BEGIN EXCAVATION OVER THE POWER HOUSE LOCATION WITH DREDGES, COMPLETING THE WORK LATER BEHIND THE COFFER DAM BEING CONSTRUCTED ON THE FAR RIGHT SIDE OF THE PICTURE. (21) - Michigan Lake Superior Power Company, Portage Street, Sault Ste. Marie, Chippewa County, MI

Brownfield reuse of dredged New York Harbor sediment by cement-based solidification/stabilization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Loest, K.; Wilk, C.M.

1998-12-31

Newly effective federal regulations restrict the ocean disposal of sediments dredged from the harbors of New York and Newark. The New York Port Authority is faced with a critical situation: find land-based disposal/uses for 10`s of millions cubic yards of sediments or lose standing as a commercial port for ocean-going ships. One of the technologies now being employed to manage the sediments is portland cement-based solidification/stabilization (S/S) treatment. At least 4 million cubic yards of the sediments will undergo cement-based S/S treatment. This treatment will immobilize heavy metals, dioxin, PCBs and other organic contaminants in the sediment. The treatment changesmore » the sediment from a environmental liability into a valuable structural fill. This structural fill is being used at two properties. The first property is an old municipal landfill in Port Newark, New Jersey. The treated sediments are being used as structural fill to cover about 20 acres of the landfill. This will allow planned redevelopment of the landfill property into a shopping mall. The second property called the Seaboard site, was the location of a coal gasification facility and later a wood preservation facility. This 160-acre property has been designated for brownfield redevelopment. Over 4 million cubic yards of treated sediments will eventually cover this site. Portland cement is the selected S/S binding reagent. Nearly 500,000 tons of cement will eventually be used to treat the sediments. Cement was selected for its ability to (a) change the peanut butter-like consistency of the sediments into a structural material and (b) to physically and chemically immobilize hazardous constituents in the sediment.« less

Dredging-Related Mortality of Dungeness Crabs Associated with Four Dredges Operating in Grays Harbor, Washington.

DTIC Science & Technology

1981-03-01

Oncorhynchus nerka ) Smolts Subjected to Entrainment During Hydraulic Dredging in the Fräser River Estuary. Environment Canada, Fisheries and Marine...Technical Report Series No. PAC/T-76-16. 35 pages. Tutty, B.D. and J. McBride. 1976. Histopathology of Chum ( Oncorhynchus keta) and Sockeye

46 CFR 170.300 - Special consideration for free surface of spoil in hopper dredge hoppers.

Code of Federal Regulations, 2010 CFR

2010-10-01

... hopper dredge hoppers. 170.300 Section 170.300 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... Special consideration for free surface of spoil in hopper dredge hoppers. The calculations required by this subchapter for each self-propelled hopper dredge must include— (a) The free surface effect of...

46 CFR 170.300 - Special consideration for free surface of spoil in hopper dredge hoppers.

Code of Federal Regulations, 2011 CFR

2011-10-01

... hopper dredge hoppers. 170.300 Section 170.300 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... Special consideration for free surface of spoil in hopper dredge hoppers. The calculations required by this subchapter for each self-propelled hopper dredge must include— (a) The free surface effect of...

Application of the Streamflow Prediction Tool to Estimate Sediment Dredging Volumes in Texas Coastal Waterways

NASA Astrophysics Data System (ADS)

Yeates, E.; Dreaper, G.; Afshari, S.; Tavakoly, A. A.

2017-12-01

Over the past six fiscal years, the United States Army Corps of Engineers (USACE) has contracted an average of about a billion dollars per year for navigation channel dredging. To execute these funds effectively, USACE Districts must determine which navigation channels need to be dredged in a given year. Improving this prioritization process results in more efficient waterway maintenance. This study uses the Streamflow Prediction Tool, a runoff routing model based on global weather forecast ensembles, to estimate dredged volumes. This study establishes regional linear relationships between cumulative flow and dredged volumes over a long-term simulation covering 30 years (1985-2015), using drainage area and shoaling parameters. The study framework integrates the National Hydrography Dataset (NHDPlus Dataset) with parameters from the Corps Shoaling Analysis Tool (CSAT) and dredging record data from USACE District records. Results in the test cases of the Houston Ship Channel and the Sabine and Port Arthur Harbor waterways in Texas indicate positive correlation between the simulated streamflows and actual dredging records.

14. DREDGING MAP. United Engineering Company Ltd., Alameda Shipyard. Ship ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

14. DREDGING MAP. United Engineering Company Ltd., Alameda Shipyard. Ship repair facilities dredging map. No architect noted. Drawn by "J.H." (John Hudspeth?). Sheet 1. Plan no. 10,529. Scale one inch to 50 feet. September 22, 1943. U.S. Navy, Bureau of Yards & Docks, Contract no. bs 76. Approved for construction October 18, 1943. blueprint - United Engineering Company Shipyard, 2900 Main Street, Alameda, Alameda County, CA

Ecological performance of construction materials subject to ocean climate change.

PubMed

Davis, Kay L; Coleman, Melinda A; Connell, Sean D; Russell, Bayden D; Gillanders, Bronwyn M; Kelaher, Brendan P

2017-10-01

Artificial structures will be increasingly utilized to protect coastal infrastructure from sea-level rise and storms associated with climate change. Although it is well documented that the materials comprising artificial structures influence the composition of organisms that use them as habitat, little is known about how these materials may chemically react with changing seawater conditions, and what effects this will have on associated biota. We investigated the effects of ocean warming, acidification, and type of coastal infrastructure material on algal turfs. Seawater acidification resulted in greater covers of turf, though this effect was counteracted by elevated temperatures. Concrete supported a greater cover of turf than granite or high-density polyethylene (HDPE) under all temperature and pH treatments, with the greatest covers occurring under simulated ocean acidification. Furthermore, photosynthetic efficiency under acidification was greater on concrete substratum compared to all other materials and treatment combinations. These results demonstrate the capacity to maximise ecological benefits whilst still meeting local management objectives when engineering coastal defense structures by selecting materials that are appropriate in an ocean change context. Therefore, mitigation efforts to offset impacts from sea-level rise and storms can also be engineered to alter, or even reduce, the effects of climatic change on biological assemblages. Copyright © 2017 Elsevier Ltd. All rights reserved.

Dredging-induced nutrient release from sediments to the water column in a southeastern saltmarsh tidal creek.

PubMed

Lohrer, Andrew M; Wetz, Jennifer Jarrell

2003-09-01

Dredging is a large-scale anthropogenic disturbance agent in coastal and estuarine habitats that can profoundly affect water quality. We examined the impact of a small-scale dredging operation in a salt marsh in South Carolina by comparing nutrient levels (NH(4)(+), NO(x), PO(4)(-)) and total suspended solid concentrations before and during dredging activities. Nutrient enrichment was evaluated within the context of tidal, seasonal, and inter-annual variability by using long-term water chemistry data provided by the North Inlet-Winyah Bay National Estuarine Research Reserve. The conditions of the dredging permit (i.e., its relatively small scale), the season chosen for the work (fall-winter), the nature of the sediments dredged (coarse-grained), and the amount of natural variability in the estuary's water chemistry (even on a daily time-scale) all minimized the impact of the dredging activities. Results of this study will add to the limited body of empirical data that should be considered in evaluating future dredging permit applications related to shallow estuarine waterways.

West Nile virus infection in horses, Indian ocean.

PubMed

Cardinale, E; Bernard, C; Lecollinet, S; Rakotoharinome, V M; Ravaomanana, J; Roger, M; Olive, M M; Meenowa, D; Jaumally, M R; Melanie, J; Héraud, J M; Zientara, S; Cêtre-Sossah, C

2017-08-01

The circulation of West Nile virus (WNV) in horses was investigated in the Southwest Indian ocean. In 2010, blood samples were collected from a total of 303 horses originating from Madagascar, Mauritius, Reunion and the Seychelles and tested for WNV-specific antibodies. An overall seroprevalence of 27.39% was detected in the Indian Ocean with the highest WNV antibody prevalence of 46.22% (95% CI: [37.4-55.2%]) in Madagascar. The age and origin of the horses were found to be associated with the WNV infection risk. This paper presents the first seroprevalence study investigating WN fever in horses in the Southwest Indian Ocean area and indicates a potential risk of infection for humans and animals. In order to gain a better understanding of WN transmission cycles, WNV surveillance needs to be implemented in each of the countries. Copyright © 2017 Elsevier Ltd. All rights reserved.

Optimal Dredge Fleet Scheduling, Phase 2

DOT National Transportation Integrated Search

2017-12-21

The U.S. Army Corps of Engineers (USACE) annually spends more than 100 million dollars on dredging hundreds of navigation projects on more than 12, 000 miles of inland and intra-coastal waterways. This project expands on a recently developed constrai...

Analyses of water, bank material, bottom material, and elutriate samples collected near Belzoni, Mississippi (upper Yazoo projects)

USGS Publications Warehouse

Brightbill, David B.; Treadway, Joseph B.

1980-01-01

Four core-material-sampling sites and one bottom-material site were chosen by the U.S. Army Corps of Engineers to represent areas of proposed dredging activity along a 24.9-mile reach of the upper Yazoo River. Five receiving-water sites also were selected to represent the water that will contact the proposed dredged material. Chemical and physical analyses were performed upon core or bottom material and native-water (receiving-water) samples from these sites as well as upon elutriate samples of the mixture of sediment and receiving water. The results of these analyses are presented without interpertation. (USGS)

Long-term effects of dredging operations program. Collation and interpretation of data for Times Beach confined disposal facility, Buffalo, New York. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stafford, E.A.; Simmers, J.W.; Rhett, R.G.

1991-06-01

This interim report, collates all data gathered for the Times Beach confined disposal facility (CDF), Buffalo, New York. This purpose of the studies at the CDF was to determine the mobility and potential hazard of contaminants known to be in the dredged material placed at Times Beach by sampling and analyzing various components of the developing ecosystems. Upland, wetland, and aquatic areas are represented within the CDF and, for each area, inventories of colonizing biota were made and samples collected for measurement of heavy metals and organic compound contaminants. Samples of dredged material, vegetation, and soil-dwelling invertebrates, and vertebrates havemore » been collected and heavy metal concentrations measured. Results suggest that the persistent contaminants, particularly cadmium, are concentrating in the leaf litter zone and moving into the detritivorous invertebrates. Highest concentrations of heavy metals were noted in earthworms. Earth worms, millipedes, woodlice, and spiders appeared to be target organisms for accumulation of heavy metals, and these groups contained higher concentrations of copper and cadmium than the other groups. Polychlorinated biphenyl (PCB) and polynuclear aromatic hydrocarbon contaminants in the dredged material were below machine detection limits in the vertebrate top-predators. Contaminant concentrations in water from ground water wells were below guidance limits.« less

Flotation as a remediation technique for heavily polluted dredged material. 2. Characterisation of flotated fractions.

PubMed

Cauwenberg, P; Verdonckt, F; Maes, A

1998-01-19

The particle size distribution and the metal speciation of the heavy metals were investigated on dredged sediment and on the fractions obtained by mechanical agitated (Denver) flotation. The transition metal ions (cadmium, copper, lead and zinc) were flotated specifically independent of the particle size. Particle size analysis, EDTA extraction and sequential extracts indicated that during flotation a redistribution of metals occurred due to the oxidation of metal sulphides. This oxidation process was more pronounced when the flotation was performed at higher pH values and resulted in a decrease in flotation specificity.

The effects of marine sand and gravel extraction on the sediment composition and macrofaunal community of a commercial dredging site (15 years post-dredging).

PubMed

Waye-Barker, Georgia A; McIlwaine, Paul; Lozach, Sophie; Cooper, Keith M

2015-10-15

A prediction that faunal recovery of a marine aggregate extraction site subjected to high dredging intensity was likely to take 15-20 years was investigated. Samples were collected at the high dredging intensity site and two reference sites in 2011 (15 years post-dredging). Results indicated that the high site had similar sediment characteristics to the reference sites by 2011. Macrofaunal data analyses showed no difference between the values of all calculated univariate measures (abundance, number of taxa, biomass and evenness) between the high and reference sites. Multivariate analyses found that the macrofaunal community at the high site was comparable to those of the reference sites by 2011. Overall, the results supported the predicted recovery time. The findings of the study suggest that persistent physical impacts prolonged the biological recovery of the high site. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

Methodology of management of dredging operations II. Applications.

PubMed

Junqua, G; Abriak, N E; Gregoire, P; Dubois, V; Mac Farlane, F; Damidot, D

2006-04-01

This paper presents the new methodology of management of dredging operations. Derived partly from existing methodologies (OECD, PNUE, AIPCN), it aims to be more comprehensive, mixing the qualities and the complementarities of previous methodologies. The application of the methodology has been carried out on the site of the Port of Dunkirk (FRANCE). Thus, a characterization of the sediments of this site has allowed a zoning of the Port to be established in to zones of probable homogeneity of sediments. Moreover, sources of pollution have been identified, with an aim of prevention. Ways of waste improvement have also been developed, to answer regional needs, from a point of view of competitive and territorial intelligence. Their development has required a mutualisation of resources between professionals, research centres and local communities, according to principles of industrial ecology. Lastly, a tool of MultiCriteria Decision-Making Aid (M.C.D.M.A.) has been used to determine the most relevant scenario (or alternative, or action) for a dredging operation intended by the Port of Dunkirk. These applications have confirmed the relevance of this methodology for the management of dredging operations.

Comparison of wetland structural characteristics between created and natural salt marshes in southwest Louisiana, USA

USGS Publications Warehouse

Edwards, K.R.; Proffitt, C.E.

2003-01-01

The use of dredge material is a well-known technique for creating or restoring salt marshes that is expected to become more common along the Gulf of Mexico coast in the future. However, the effectiveness of this restoration method is still questioned. Wetland structural characteristics were compared between four created and three natural salt marshes in southwest Louisiana, USA. The created marshes, formed by the pumping of dredge material into formerly open water areas, represent a chronosequence, ranging in age from 3 to 19 years. Vegetation and soil structural factors were compared to determine whether the created marshes become more similar over time to the natural salt marshes. Vegetation surveys were conducted in 1997, 2000, and 2002 using the line-intercept technique. Site elevations were measured in 2000. Organic matter (OM) was measured in 1996 and 2002, while bulk density and soil particle-size distribution were determined in 2002 only. The natural marshes were dominated by Spartina alterniflora, as were the oldest created marshes; these marshes had the lowest mean site elevations ( 35 cm NGVD) and became dominated by high marsh (S. patens, Distichlis spicata) and shrub (Baccharis halimifolia, Iva frutescens) species. The higher elevation marsh seems to be following a different plant successional trajectory than the other marshes, indicating a relationship between marsh elevation and species composition. The soils in both the created and natural marshes contain high levels of clays (30-65 %), with sand comprising < 1 % of the soil distribution. OM was significantly greater and bulk density significantly lower in two of the natural marshes when compared to the created marshes. The oldest created marsh had significantly greater OM than the younger created marshes, but it may still take several decades before equivalency is reached with the natural marshes. Vegetation structural characteristics in the created marshes take only a few years to become similar

Reproductive biology of the spotback skate Atlantoraja castelnaui in the south-west Atlantic Ocean.

PubMed

Colonello, J C; García, M L; Lasta, C A; Menni, R C

2012-06-01

This study provides information on the reproduction of spotback skate Atlantoraja castelnaui. A total of 232 individuals (119 females and 113 males) were obtained from surveys carried out between 2003 and 2006, from the south-west Atlantic Ocean, between 34 and 42° S and <50 m deep; another 514 specimens (241 females and 273 males) were obtained between 2005 and 2007 from commercial fishery operations carried out in the same area and landings in the port of Mar del Plata, Argentina. Males ranged from 185 to 1250 mm total length (L(T) ) and females from 243 to 1368 mm L(T) . Length at maturity was estimated to be 980 mm for males and 1089 mm L(T) for females. Lack of variation of testis mass together with the continuous production of mature spermatocyst and spermatozoa in deferent ducts suggested that males can reproduce throughout the year. Females reproduced year-round with peaks of reproductive activity an integral part of a continuous cycle. This conclusion is corroborated by the seasonal variation of ovaries, oviducal gland and the occurrence of females with eggs in the uterus throughout the year. Results from this study indicate that A. castelnaui is very susceptible to fishery pressure. © 2012 The Authors. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.

Abundances and test weights of living planktic foraminifers across the Southwest Indian Ocean: Implications for carbon fluxes

NASA Astrophysics Data System (ADS)

Meilland, J.; Schiebel, R.; Lo Monaco, C.; Sanchez, S.; Howa, H.

2018-01-01

Calcifying marine organisms include planktic foraminifers that contribute to the marine carbon turnover by generating inorganic carbon production (CaCO3, shell) and flux. In this study, we have analyzed assemblages at the morphospecies level and abundances of living planktic foraminifers (LPF) from ten stations located in the Southwest Indian Ocean, and sampled in austral summer 2012. LPF density ranges from zero in the Subtropical Zone (STZ) to 944 individuals m-3 in the Polar Frontal Zone (PFZ), and is composed by up to 80% by the four species Neogloboquadrina pachyderma, Neogloboquadrina incompta, Globigerina bulloides, and Globigerinita uvula. For the entire region, we measured the individual morphometry and test mass (CaCO3) of 454 tests of living planktic foraminifers in order to calculate inorganic carbon standing stocks, as well as carbon flux. In the STZ, the average daily planktic foraminifer CaCO3 flux at 100 m water depth is low (< 0.22 mg m-2 d-1), whereas south of the Sub-Antarctic Zone (SAZ), in the PFZ and Antarctic Zone (AAZ), it reaches up to 49.41 mg m-2 d-1, and 2.20 mg m-2 d-1, respectively. The large regional variability in CaCO3 production and flux of LPF assemblages affects the marine carbonate system to varying degrees, depending on hydrological conditions. We conclude that recent changes in the position of hydrological fronts could induce a decrease in the LPF-related carbonate counter pump, which increases the oceanic uptake of CO2, and counteracts climate warming.

Updating the distribution and habitat pattern of Maurolicus stehmanni (Sternoptychidae, Stomiformes) in the Southwest Atlantic Ocean

NASA Astrophysics Data System (ADS)

Belleggia, Mauro; Villanueva-Gomila, Gabriela Lujan; Buratti, Claudio; Colombo, Gustavo Alvarez; Figueroa, Daniel Enrique; Venerus, Leonardo Ariel

2018-06-01

We updated the distribution and habitat patterns of Maurolicus stehmanni in the Southwest Atlantic Ocean by compiling data obtained from research surveys conducted on the Argentinean continental shelf, as well as from opportunistic records. This paper confirms the presence of M. stehmanni in the Argentinean continental shelf, extending its southernmost distributional limit by ca. 1000 km (from 43.0°S to 52.2°S). Adult specimens of M. stehmanni were collected in various locations from 2004 to 2016. Eggs and larvae of Maurolicus spp. were caught during ichthyoplankton tows carried out from 2003 to 2013. The present paper furthermore extends the habitat type in which this species was recorded: specimens were found in the inner continental shelf (between 46.2°S and 52.2°S) instead of the shelf break and continental slope. Two specimens were found lying dead upon the beach of Puerto Madryn, Nuevo Gulf (42.8°S). The presence of eggs and larvae in coastal embayments (San Matías and San José gulfs), in concomitant occurrence with adults, may suggest the establishment of this species in the region.

Southwest Energy Efficiency Project (SWEEP) Final Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Geller, Howard; Meyers, Jim

SWEEP worked with Energy Efficiency and Renewable Energy (EERE) programs to foster greater energy efficiency throughout the Southwest. SWEEP accomplished this through a combination of analysis and support; preparation and distribution of materials on best practice technologies, policies and programs; and technical assistance and information dissemination to states and municipalities in the southwest supporting BTO, AMO, OWIP for advancement of efficiency in products and practices. These efforts were accomplished during the period 2012 through 2017.

DREDGING IMPACT ON AN URBANIZED FLORIDA BAYOU: EFFECTS ON BENTHOS AND ALGAL-PERIPHYTON.

EPA Science Inventory

Environmental effects of dredging events have been uncommonly reported for shallow, residential estuaries characteristic of the Gulf of Mexico region. The objective of this study was to determine the impact of hydraulic dredging on an urbanized estuary. Physicochemical quality, ...

Detecting sedimentation impacts to coral reefs resulting from dredging the Port of Miami, Florida USA

PubMed Central

Groves, Carolyn E.; Griffin, Sean; Moore, Tom; Wilber, Pace; Gregg, Kurtis

2016-01-01

The federal channel at Port of Miami, Florida, USA, was dredged between late 2013 and early 2015 to widen and deepen the channel. Due to the limited spatial extent of impact-assessment monitoring associated with the project, the extent of the dredging impacts on surrounding coral reefs has not been well quantified. Previously published remote sensing analyses, as well as agency and anecdotal reports suggest the most severe and largest area of sedimentation occurred on a coral reef feature referred to as the Inner Reef, particularly in the sector north of the channel. A confounding regional warm-water mass bleaching event followed by a coral disease outbreak during this same time frame made the assessment of dredging-related impacts to coral reefs adjacent to the federal channel difficult but still feasible. The current study sought to better understand the sedimentation impacts that occurred in the coral reef environment surrounding Port of Miami, to distinguish those impacts from other regional events or disturbances, and provide supplemental information on impact assessment that will inform discussions on compensatory mitigation requirements. To this end, in-water field assessments conducted after the completion of dredging and a time series analysis of tagged corals photographed pre-, during, and post-dredging, are used to discern dredging-related sedimentation impacts for the Inner Reef north. Results indicate increased sediment accumulation, severe in certain times and places, and an associated biological response (e.g., higher prevalence of partial mortality of corals) extended up to 700 m from the channel, whereas project-associated monitoring was limited to 50 m from the channel. These results can contribute to more realistic prediction of areas of indirect effect from dredging projects needed to accurately evaluate proposed projects and design appropriate compliance monitoring. Dredging projects near valuable and sensitive habitats subject to local and

Detecting sedimentation impacts to coral reefs resulting from dredging the Port of Miami, Florida USA.

PubMed

Miller, Margaret W; Karazsia, Jocelyn; Groves, Carolyn E; Griffin, Sean; Moore, Tom; Wilber, Pace; Gregg, Kurtis

2016-01-01

The federal channel at Port of Miami, Florida, USA, was dredged between late 2013 and early 2015 to widen and deepen the channel. Due to the limited spatial extent of impact-assessment monitoring associated with the project, the extent of the dredging impacts on surrounding coral reefs has not been well quantified. Previously published remote sensing analyses, as well as agency and anecdotal reports suggest the most severe and largest area of sedimentation occurred on a coral reef feature referred to as the Inner Reef, particularly in the sector north of the channel. A confounding regional warm-water mass bleaching event followed by a coral disease outbreak during this same time frame made the assessment of dredging-related impacts to coral reefs adjacent to the federal channel difficult but still feasible. The current study sought to better understand the sedimentation impacts that occurred in the coral reef environment surrounding Port of Miami, to distinguish those impacts from other regional events or disturbances, and provide supplemental information on impact assessment that will inform discussions on compensatory mitigation requirements. To this end, in-water field assessments conducted after the completion of dredging and a time series analysis of tagged corals photographed pre-, during, and post-dredging, are used to discern dredging-related sedimentation impacts for the Inner Reef north. Results indicate increased sediment accumulation, severe in certain times and places, and an associated biological response (e.g., higher prevalence of partial mortality of corals) extended up to 700 m from the channel, whereas project-associated monitoring was limited to 50 m from the channel. These results can contribute to more realistic prediction of areas of indirect effect from dredging projects needed to accurately evaluate proposed projects and design appropriate compliance monitoring. Dredging projects near valuable and sensitive habitats subject to local and

Ocean heat budget analysis on sea surface temperature anomaly in western Indian Ocean during strong-weak Asian summer monsoon

NASA Astrophysics Data System (ADS)

Fathrio, Ibnu; Manda, Atsuyoshi; Iizuka, Satoshi; Kodama, Yasu-Masa; Ishida, Sachinobu

2018-05-01

This study presents ocean heat budget analysis on seas surface temperature (SST) anomalies during strong-weak Asian summer monsoon (southwest monsoon). As discussed by previous studies, there was close relationship between variations of Asian summer monsoon and SST anomaly in western Indian Ocean. In this study we utilized ocean heat budget analysis to elucidate the dominant mechanism that is responsible for generating SST anomaly during weak-strong boreal summer monsoon. Our results showed ocean advection plays more important role to initate SST anomaly than the atmospheric prcess (surface heat flux). Scatterplot analysis showed that vertical advection initiated SST anomaly in western Arabian Sea and southwestern Indian Ocean, while zonal advection initiated SST anomaly in western equatorial Indian Ocean.

75 FR 19311 - Ocean Dumping; Guam Ocean Dredged Material Disposal Site Designation

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-14

..., landfill daily cover, and recycling into commercial products such as construction aggregate, ceramic tiles... subject its sediments to a battery of physical, chemical, and biological tests to determine suitability...

Field Verification Program (Aquatic Disposal). The Assessment of Black Rock Harbor Dredged Material Impacts on Laboratory Population Responses.

DTIC Science & Technology

1987-07-01

report describes work performed by the US Environmental Protection Agency (USEPA), Environmental Research Laboratory, Narragansett, R. I. (ERLN), as...of the use 2 such commercial prodluc!s TheP 0-series of reports includes Qubiicatiors Environmental Effects of Dredclng Proqramrs Dredg:ng Operations...public release; distribution 2b DECLASSIFICATION /DOWNGRADING SCHEDULE unlimited. 4 PERFORMING ORGANIZATION REPORT NUMBER(S) S MONITORING

Quantification of the indirect effects of scallop dredge fisheries on a brown crab fishery.

PubMed

Öndes, Fikret; Kaiser, Michel J; Murray, Lee G

2016-08-01

This study aimed to describe the characteristics of the by-catch of Cancer pagurus in king scallop dredges in the Isle of Man, and to determine the damage, immediate mortality and estimated mortality during fishing seasons associated with scallop dredges. Based on dredge surveys, spatial and seasonal variations were observed, with the highest number of crabs found off the west coast of the Isle of Man in the autumn when berried females crabs were most frequently caught. In general, female crabs comprised 84% of the catch. The damage levels of crabs was high with 45% of crabs recorded as crushed or dead or with severe damage, whilst 24% of crabs exhibited missing limbs. Estimates of the potential mortality associated with scallop dredging led to a lower and upper estimate of possible crab by-catch mortality of 15t and 24t respectively which represented 3.0-4.8% of the commercial landings of brown crab for the Isle of Man. Heaviest mortalities of crabs occurred in autumn to the west of the Isle of Man when female berried crabs move offshore into deeper water. The use of a temporary and spatially restricted scallop dredging closure could provide a simple solution to mitigate additional crab mortality in the event that scallop dredging increased beyond current levels in the future. Copyright © 2016 Elsevier Ltd. All rights reserved.

Comparisons of benthic filter feeder communities before and after a large-scale capital dredging program.

PubMed

Abdul Wahab, Muhammad Azmi; Fromont, Jane; Gomez, Oliver; Fisher, Rebecca; Jones, Ross

2017-09-15

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. Community functional morphological composition was quantified using towed video surveys, while dive surveys allowed for assessments of species composition and chlorophyll content. Onslow is relatively diverse recording 150 sponge species. The area was naturally turbid (1.1 mean P 80 NTU), with inshore sites recording 6.5× higher turbidity than offshore localities, likely influenced by the Ashburton River discharge. Turbidity and sedimentation increased by up to 146% and 240% through dredging respectively, with corresponding decreases in light levels. The effects of dredging was variable, and despite existing caveats (i.e. bleaching event and passing of a cyclone), the persistence of sponges and the absence of a pronounced response post-dredging suggest environmental filtering or passive adaptation acquired pre-dredging may have benefited these communities. Copyright © 2017. Published by Elsevier Ltd.

Effects of contaminated dredge spoils on wetland plant communities: A literature review

USGS Publications Warehouse

Stewart, Paul M.; Garza, Eric L.; Butcher, Jason T.; Simon, Thomas P.

2003-01-01

Contaminated dredge spoil is a national concern due to its scope and effects on biota, water quality, and the physical environment. This literature review discusses the effects of contaminated dredge spoils on wetland plant communities. Plant communities naturally shift over time with changing environmental conditions. Addition of toxins and nutrients and changes in hydrology may influence plant community structure. The storage and disposal of nutrient and metal contaminated dredge spoils may cause shifts in nearby plant communities. Shifts in species composition and diversity may not be observed for decades after nutrient enrichment, causing any disturbance to remain undetected. Plant community shifts often have great amounts of inertia and are difficult to reverse.

Sediment Management Methods to Reduce Dredging: Part 2, Sediment Collector Technology

DTIC Science & Technology

2017-04-01

Approved for public release; distribution is unlimited. ERDC TN-DOER-T13 April 2017 Sediment Management Methods to Reduce Dredging: Part 2...DOER) Program technical note (TN) is the second in a series evaluating sediment management methods to reduce dredging through a research task (RT...in the DOER Program.1 This TN presents an evaluation of sediment collector technology, one promising new device that may help better manage

Impact of Indian ocean dipole on the coastal upwelling features off the southwest coast of India

NASA Astrophysics Data System (ADS)

Nigam, Tanuja; Pant, Vimlesh; Prakash, Kumar Ravi

2018-05-01

A three-dimensional regional ocean model is used to examine the impact of positive Indian ocean dipole (pIOD) events on the coastal upwelling features at the southwest coast of India (SWCI). Two model experiments are carried out with different surface boundary conditions that prevailed in the normal and pIOD years from 1982 to 2010. Model experiments demonstrate the weakening of coastal upwelling at the SWCI in the pIOD years. The reduced southward meridional wind stress off the SWCI leads to comparatively lower offshore Ekman transport during August-October in the pIOD years to that in normal years. The suppressed coastal upwelling results in warmer sea surface temperature and deeper thermocline in the pIOD years during June-September. The offshore spatial extent of upwelled colder (< 22 °C) water was up to 75.5° E in August-September in normal years that was limited up to 76.2° E in pIOD years. The heat budget analysis reveals the decreased contribution of vertical entrainment process to the mixed layer cooling in pIOD years which is almost half of that of normal years in October. The net heat flux term shows warming tendency during May-November with a higher magnitude (+ 0.4 °C day-1) in normal years than pIOD years (+ 0.28 °C day-1). The biological productivity is found to reduce during the pIOD years as the concentration of phytoplankton and zooplankton decreases over the region of coastal upwelling at SWCI. Nitrate concentration in the pIOD years dropped by half during August-September and dropped by an order of magnitude in October as compared to its ambient concentration of 13 μmol L-1 in normal years.

Impact of Indian ocean dipole on the coastal upwelling features off the southwest coast of India

NASA Astrophysics Data System (ADS)

Nigam, Tanuja; Pant, Vimlesh; Prakash, Kumar Ravi

2018-06-01

A three-dimensional regional ocean model is used to examine the impact of positive Indian ocean dipole (pIOD) events on the coastal upwelling features at the southwest coast of India (SWCI). Two model experiments are carried out with different surface boundary conditions that prevailed in the normal and pIOD years from 1982 to 2010. Model experiments demonstrate the weakening of coastal upwelling at the SWCI in the pIOD years. The reduced southward meridional wind stress off the SWCI leads to comparatively lower offshore Ekman transport during August-October in the pIOD years to that in normal years. The suppressed coastal upwelling results in warmer sea surface temperature and deeper thermocline in the pIOD years during June-September. The offshore spatial extent of upwelled colder (< 22 °C) water was up to 75.5° E in August-September in normal years that was limited up to 76.2° E in pIOD years. The heat budget analysis reveals the decreased contribution of vertical entrainment process to the mixed layer cooling in pIOD years which is almost half of that of normal years in October. The net heat flux term shows warming tendency during May-November with a higher magnitude (+ 0.4 °C day-1) in normal years than pIOD years (+ 0.28 °C day-1). The biological productivity is found to reduce during the pIOD years as the concentration of phytoplankton and zooplankton decreases over the region of coastal upwelling at SWCI. Nitrate concentration in the pIOD years dropped by half during August-September and dropped by an order of magnitude in October as compared to its ambient concentration of 13 μmol L-1 in normal years.

Occurrence of high-Al N-MORB along the Easternmost Southwest Indian Ridge

NASA Astrophysics Data System (ADS)

Meyzen, C. M.; Humler, E.; Ludden, J. N.

2017-12-01

One of the deepest and slowest part of the mid-ocean-ridge system lies within the easternmost part of the Southwest Indian Ridge between 61°E and 69° E. In this region, a distinctive sea-floor terrain characterized by high-relief segments separated by long, deep tectonized sections shows a predominance of tectonic over magmatic extensional processes, suggesting an unstable and weak, but locally focalized magma supply. Other features of this section include the absence of long-lived transforms, thick lithosphere, high upper mantle seismic wave velocities and thin oceanic crust (4-5 km). When compared to other ridge segments, most MORB erupted along this section distinguish themselves by their higher Na2O, Sr and Al2O3 compositions, very low CaO/Al2O3 ratios relative to TiO2 and depleted heavy rare-earth element (REE) distributions. Another peculiar feature is their subparallel LREE enriched patterns. The high-Al-MgO magma type erupted periodically around the ridge system is also found in this region at 61.93°E. These lavas are characterized by high Al2O3 (> 17 wt. %), MgO (> 8.8 wt. %) and FeO contents, low SiO2 (< 49 wt. %) and Na2O and very low TiO2 (< 1 wt. %), and a LREE depleted pattern compared to the main population. At slightly lower MgO, sporadically, two other dredges located at 63.36-63.66°E share some of these distinct compositional characteristics. As a whole, these lavas are the most depleted in highly incompatible elements, but are also characterized by an offset toward lower MREE/HREE ratios relative to the main population. These peculiar basalts are not parental to the more common lower MgO compositions and cannot be related to them by fractional crystallization alone. Instead, their major element features, and the occasional presence of positive Eu and Sr anomalies might indicate assimilation of plagioclase cumulates, while their offset in MREE/HREE might require a multistage melting evolution with an earlier event in the garnet stability field.

Phytoplankton community indicators of changes associated with dredging in the Tagus estuary (Portugal).

PubMed

Cabrita, Maria Teresa

2014-08-01

This work reports changes in suspended particulate matter, turbidity, dissolved Cr, Ni, Cu, Cd, Hg and Pb concentrations, and phytoplankton biomass and composition during a 5-month period dredging operation, in a trace element contaminated area of the Tagus estuary (Portugal). Phytoplankton biomass, diatom:other groups ratio, benthic:pelagic diatom ratio, Margalef's, Simpson's diversity, Shannon-Wiever's, and Warwick and Clarke's taxonomic diversity and distinctness indices, and individual taxa were investigated as indicators of dredging induced changes. Significant rise in sediment resuspension and trace element mobilisation caused by dredging influenced the community structure but not the overall biomass. Benthic diatom displacement into the water column maintained species diversity, and therefore, none of the indices highlighted community changes. Contrastingly, diatom:other groups ratio and benthic:pelagic diatom ratio were reliable indicators for the assessment of dredging induced changes. A shift in composition towards species less susceptible to trace elements was observed, disclosing some individual taxa as potential indicators. Copyright © 2014 Elsevier Ltd. All rights reserved.

Dredge-up and Envelope Burning in Intermediate-Mass Giants of Very Low Metallicity

NASA Astrophysics Data System (ADS)

Herwig, Falk

2004-04-01

The evolution of intermediate-mass stars at very low metallicity during their final thermal pulse asymptotic giant branch (AGB) phase is studied in detail. As representative examples, models with initial masses of 4 and 5Msolar and with a metallicity of Z=0.0001 ([Fe/H]~-2.3) are discussed. The one-dimensional stellar structure and evolution model includes time- and depth-dependent overshooting motivated by hydrodynamic simulations, as well as a full nuclear network and time-dependent mixing. Particular attention is given to high time and space resolution to avoid numerical artifacts related to third dredge-up and hot bottom burning predictions. The model calculations predict very efficient third dredge-up that mixes the envelope with the entire intershell layer or a large fraction thereof and in some cases penetrates into the C/O core below the He shell. In all cases primary oxygen is mixed into the envelope. The models predict efficient envelope burning during the interpulse phase. Depending on the envelope-burning temperature, oxygen is destroyed to varying degrees. The combined effect of dredge-up and envelope burning does not lead to any significant oxygen depletion in any of the cases considered in this study. The large dredge-up efficiency in our model is closely related to the particular properties of the H shell during the dredge-up phase in low-metallicity very metal-poor stars, which is followed here over many thermal pulses. During the dredge-up phase, the temperature just below the convective boundary is large enough for protons to burn vigorously when they are brought into the C-rich environment below the convection boundary by the time- and depth-dependent overshooting. H-burning luminosities of 105 to ~2×106Lsolar are generated. C, and to lesser degree O, is transformed into N in this dredge-up overshooting layer and enters the envelope. The global effect on the CNO abundance is similar to that of hot bottom burning. If the overshoot efficiency is

Clam dredging effects and subsequent recovery of benthic communities at different depth ranges.

PubMed

Constantino, R; Gaspar, M B; Tata-Regala, J; Carvalho, S; Cúrdia, J; Drago, T; Taborda, R; Monteiro, C C

2009-03-01

This study aimed to assess the potential effects of clam dredging and the subsequent recovery of the benthic environment. Two experimental areas located at 6 and 18m depth were established in order to analyse whether impacts and recovery of benthic environment are depth-related. Study areas were located within an area closed to dredging and two different plots were established at both depths. One of the plots was subjected to intense clam dredge-fishing, while the other was undisturbed and therefore used as control. Sampling followed a BACI design, with samples for macrobenthic, meiobenthic and sediment particle size analysis being taken by SCUBA divers from both areas before and after fishing stress. For both depths, impacts on the benthic environment were very low resulting in high recovery rates. Nevertheless, at shallower depths communities demonstrated a faster recovery. It was shown that depending on the faunal component used as a bioindicator, different results can be observed. Generally deposit-feeding organisms with scales or chitinous plates and vermiform shape (mainly crustaceans, polychaetes and ophiuroids), without external protection, were the most affected by dredging, while some polychaetes without external protection and with a carnivorous feeding mode seemed to be enhanced by fishing. The low level of perturbations induced by the dredging activities was comparable to the impact of surface waves on the bottom, as experiments were undertaken in wave-dominated environments. The coexistence of storm events during the study period proved to have similar or even more deleterious effects on the benthic environment. It appears that communities from hydrodynamic fishing grounds that are well adapted to natural physical stress are not highly affected by dredging.

A temporal and spatial assessment of TBT concentrations at dredged material disposal sites around the coast of England and Wales.

PubMed

Bolam, Thi; Barry, Jon; Law, Robin J; James, David; Thomas, Boby; Bolam, Stefan G

2014-02-15

Despite legislative interventions since the 1980s, contemporary concentrations of organotin compounds in marine sediments still impose restrictions on the disposal of dredged material in the UK. Here, we analyse temporal and spatial data to assess the effectiveness of the ban on the use of TBT paints in reducing concentrations at disposal sites. At a national scale, there was a statistically significant increase in the proportion of samples in which the concentration was below the limit of detection (LOD) from 1998 to 2010. This was observed for sediments both inside and outside the disposal sites. However, this temporal decline in organotin concentration is disposal site-specific. Of the four sites studied in detail, two displayed significant increases in proportion of samples below LOD over time. We argue that site-specificity in the effectiveness of the TBT ban results from variations in historical practices at source and unique environmental characteristics of each site. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

A Critical Test of Nd isotopes as a Paleocirculation Proxy in the Southwest Atlantic

NASA Astrophysics Data System (ADS)

Wu, Y.; Goldstein, S. L.; Pena, L.; Hartman, A. E.; Rijkenberg, M. J. A.; de Baar, H. J. W.

2016-12-01

The application of Nd isotopes as a paleo-ocean circulation tracer assumes that Nd isotope ratios (ɛNd) effectively fingerprint different water masses and approximate expected values from water mass mixing. The Southwest Atlantic, with the major water masses involved in the Atlantic Meridional Ocean Circulation (southward flowing North Atlantic Deep Water, northward flowing Antarctic Intermediate Water and Antarctic Bottom Water), is one of the best places on Earth to evaluate how well Nd isotope ratios act like a conservative water mass tracer in the modern ocean. Seawater profiles and core-top sediments from 17 stations were sampled in the Southwest Atlantic in the South Atlantic Meridional GEOTRACES cruise (GA02 Leg 3; RRS James Cook 057) between Tierra del Fuego and the Equator. Along the cruise track, along with the possibility of "boundary exchange", there are several additional potential sources that could add external Nd to seawater and disturb the "quasi-conservative" behavior of ɛNd. For example, it transects the continental shelf in the far south, the Rio Grande Rise, volcanic seamounts, and the major geological age boundaries of South America. It also crosses the major Southern Hemisphere wind zones, allowing us to test the impacts of eolian dust input, as well as inputs from major rivers. Our results on seawater ɛNd show strikingly that the Southwest Atlantic transect confirms "quasi-conservative" behavior of ɛNd in intermediate and deep water. Shallow depths show local impacts but these are not transferred to intermediate and deep water.

Environmental effects of dredging. Documentation of the dyecon module for ADDAMS: Determining the hydraulic retention and efficiency of confined disposal facilities. Technical note

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hayes, D.F.; Schroeder, P.R.; Engler, R.M.

This technical note describes procedures for determining mean hydraulic retention time and efficiency of a confined disposal facility (CDF) from a dye tracer slug test. These parameters are required to properly design a CDF for solids retention and for effluent quality considerations. Detailed information on conduct and analysis of dye tracer studies can be found in Engineer Manual 1110-2-5027, Confined Dredged Material Disposal. This technical note documents the DYECON computer program which facilitates the analysis of dye tracer concentration data and computes the hydraulic efficiency of a CDF as part of the Automated Dredging and Disposal Alternatives Management System (ADDAMS).

Credit PSR. Northeast and southwest facades of Sewage Pumping Station ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Credit PSR. Northeast and southwest facades of Sewage Pumping Station (Building 4330). Building retains its World War II construction materials and character. In the background at the extreme left is Building 4305 (Unicon Portable Hangar) - Edwards Air Force Base, North Base, Sewage Pumping Station, Southwest of E Street, Boron, Kern County, CA

From magma-poor Ocean Continent Transitions to steady state oceanic spreading: the balance between tectonic and magmatic processes

NASA Astrophysics Data System (ADS)

Gillard, Morgane; Manatschal, Gianreto; Autin, Julia; Decarlis, Alessandro; Sauter, Daniel

2016-04-01

The evolution of magma-poor rifted margins is linked to the development of a transition zone whose basement is neither clearly continental nor oceanic. The development of this Ocean-Continent Transition (OCT) is generally associated to the exhumation of serpentinized mantle along one or several detachment faults. That model is supported by numerous observations (IODP wells, dredges, fossil margins) and by numerical modelling. However, if the initiation of detachment faults in a magma-poor setting tends to be better understood by numerous studies in various area, the transition with the first steady state oceanic crust and the associated processes remain enigmatic and poorly studied. Indeed, this latest stage of evolution appears to be extremely gradual and involves strong interactions between tectonic processes and magmatism. Contrary to the proximal part of the exhumed domain where we can observe magmatic activity linked to the exhumation process (exhumation of gabbros, small amount of basalts above the exhumed mantle), in the most distal part the magmatic system appears to be independent and more active. In particular, we can observe large amounts of extrusive material above a previously exhumed and faulted basement (e.g. Alps, Australia-Antarctica margins). It seems that some faults can play the role of feeder systems for the magma in this area. Magmatic underplating is also important, as suggested by basement uplift and anomalously thick crust (e.g. East Indian margin). It results that the transition with the first steady state oceanic crust is marked by the presence of a hybrid basement, composed by exhumed mantle and magmatic material, whose formation is linked to several tectonic and magmatic events. One could argue that this basement is not clearly different from an oceanic basement. However, we consider that true, steady state oceanic crust only exists, if the entire rock association forming the crust is created during a single event, at a localized

Study on the changes of nitrogen and phosphorus release with time from sediment in Taihu Lake after ecological dredging

NASA Astrophysics Data System (ADS)

Hu, Xiaodong; Wu, Sushu; Zhu, Min; Weng, Songgan; Guo, Liuchao

2017-06-01

The changes of nitrogen and phosphorus release with time from sediment in Taihu Lake after ecological dredging were tested in laboratory. Experiment results showed that in a simulated environment of Taihu Lake, dredging was effective to reduce the endogenous pollution release, and the effect weakened gradually along with time. When the velocity of flow increased, nitrogen and phosphorus release intensity increased, so did the largest nitrogen and phosphorus emission. Considered the resedimentation, the release of nitrogen and phosphorus were similar in the area of five years after dredging and just dredging. Re-dredging should be considered.

A Surface "Superconvergence" Pathway Connecting the South Indian Ocean to the Subtropical South Pacific Gyre

NASA Astrophysics Data System (ADS)

Maes, C.; Grima, N.; Blanke, B.; Martinez, E.; Paviet-Salomon, T.; Huck, T.

2018-02-01

We study the dispersion and convergence of marine floating material by surface currents from a model reanalysis that represents explicitly mesoscale eddy variability. Lagrangian experiments about the long-term evolution (29 years) of an initially homogeneous concentration of particles are performed at global scale with horizontal current at one fourth degree resolution and refreshed daily over the 1985-2013 period. Results not only confirm and document the five known sites of surface convergence at the scale of individual oceanic basins but also reveal a convergent pathway connecting the South Indian subtropical region with the convergence zone of the South Pacific through the Great Australian Bight, the Tasman Sea, and the southwest Pacific Ocean. This "superconvergent" pathway at the ocean surface is robust and permanent over a distance longer than 8,000 km. The current variability is crucial to sustain this pathway.

Technical guidelines for environmental dredging of contaminated sediments

DOT National Transportation Integrated Search

2008-09-01

This report provides technical guidelines for evaluating : environmental dredging as a sediment remedy component. This document : supports the Contaminated Sediment Remediation Guidance for : Hazardous Waste Sites, released by the U.S. Environmental ...

Evaluation of the boundary condition influence on PAH concentrations in the water column during the sediment dredging of a port.

PubMed

Cutroneo, L; Castellano, M; Carbone, C; Consani, S; Gaino, F; Tucci, S; Magrì, S; Povero, P; Bertolotto, R M; Canepa, G; Capello, M

2015-12-30

The mobilisation of sediments and related contaminants connected to dredging activities is one of the most critical issues to the environmental risk and exposure assessment of a dredging project. The aim of this paper was an investigation of the mobilisation of polycyclic aromatic hydrocarbons (PAHs) due to the dredging of the Port of Genoa (Italy) to identify the temporal and spatial extent of the contaminant transport, and the influence of the dredging and the boundary conditions on it. The results showed relatively low background PAH concentrations in the water column and confirmed the dredging as the primary rising factor of concentrations in the water column, but also showed a complex scenario in which the different environmental and dredging factors forced the concentrations at different levels and moments. The post dredging phase showed PAH values close to the background conditions and the concentrations remained relatively high only for a few PAHs.

Ross Sea Mollusca from the Latitudinal Gradient Program: R/V Italica 2004 Rauschert dredge samples

PubMed Central

Ghiglione, Claudio; Alvaro, Maria Chiara; Griffiths, Huw J.; Linse, Katrin; Schiaparelli, Stefano

2013-01-01

Abstract Information regarding the molluscs in this dataset is based on the Rauschert dredge samples collected during the Latitudinal Gradient Program (LGP) on board the R/V “Italica” in the Ross Sea (Antarctica) in the austral summer 2004. A total of 18 epibenthic dredge deployments/samplings have been performed at four different locations at depths ranging from 84 to 515m by using a Rauschert dredge with a mesh size of 500μm. In total 8,359 specimens have been collected belonging to a total of 161 species. Considering this dataset in terms of occurrences, it corresponds to 505 discrete distributional records (incidence data). Of these, in order of abundance, 5,965 specimens were Gastropoda (accounting for 113 species), 1,323 were Bivalvia (accounting for 36 species), 949 were Aplacophora (accounting for 7 species), 74 specimens were Scaphopoda (3 species), 38 were Monoplacophora (1 species) and, finally, 10 specimens were Polyplacophora (1 species). This data set represents the first large-scale survey of benthic micro-molluscs for the area and provides important information about the distribution of several species, which have been seldom or never recorded before in the Ross Sea. All vouchers are permanently stored at the Italian National Antarctic Museum (MNA), Section of Genoa, enabling future comparison and crosschecking. This material is also currently under study, from a molecular point of view, by the barcoding project “BAMBi” (PNRA 2010/A1.10). PMID:24146597

Long-term decline in krill stock and increase in salps within the Southern Ocean.

PubMed

Atkinson, Angus; Siegel, Volker; Pakhomov, Evgeny; Rothery, Peter

2004-11-04

Antarctic krill (Euphausia superba) and salps (mainly Salpa thompsoni) are major grazers in the Southern Ocean, and krill support commercial fisheries. Their density distributions have been described in the period 1926-51, while recent localized studies suggest short-term changes. To examine spatial and temporal changes over larger scales, we have combined all available scientific net sampling data from 1926 to 2003. This database shows that the productive southwest Atlantic sector contains >50% of Southern Ocean krill stocks, but here their density has declined since the 1970s. Spatially, within their habitat, summer krill density correlates positively with chlorophyll concentrations. Temporally, within the southwest Atlantic, summer krill densities correlate positively with sea-ice extent the previous winter. Summer food and the extent of winter sea ice are thus key factors in the high krill densities observed in the southwest Atlantic Ocean. Krill need the summer phytoplankton blooms of this sector, where winters of extensive sea ice mean plentiful winter food from ice algae, promoting larval recruitment and replenishing the stock. Salps, by contrast, occupy the extensive lower-productivity regions of the Southern Ocean and tolerate warmer water than krill. As krill densities decreased last century, salps appear to have increased in the southern part of their range. These changes have had profound effects within the Southern Ocean food web.

Effects of combined dredging-related stressors on sponges: a laboratory approach using realistic scenarios.

PubMed

Pineda, Mari-Carmen; Strehlow, Brian; Kamp, Jasmine; Duckworth, Alan; Jones, Ross; Webster, Nicole S

2017-07-12

Dredging can cause increased suspended sediment concentrations (SSCs), light attenuation and sedimentation in marine communities. In order to determine the combined effects of dredging-related pressures on adult sponges, three species spanning different nutritional modes and morphologies were exposed to 5 treatment levels representing realistic dredging scenarios. Most sponges survived under low to moderate turbidity scenarios (SSCs of ≤ 33 mg L -1 , and a daily light integral of ≥0.5 mol photons m -2 d -1 ) for up to 28 d. However, under the highest turbidity scenario (76 mg L -1 , 0.1 mol photons m -2 d -1 ) there was 20% and 90% mortality of the phototrophic sponges Cliona orientalis and Carteriospongia foliascens respectively, and tissue regression in the heterotrophic Ianthella basta. All three sponge species exhibited mechanisms to effectively tolerate dredging-related pressures in the short term (e.g. oscula closure, mucus production and tissue regression), although reduced lipids and deterioration of sponge health suggest that longer term exposure to similar conditions is likely to result in higher mortality. These results suggest that the combination of high SSCs and low light availability can accelerate mortality, increasing the probability of biological effects, although there is considerable interspecies variability in how adult sponges respond to dredging pressures.

Decontamination and functional reclamation of dredged brackish sediments.

PubMed

Doni, S; Macci, C; Peruzzi, E; Iannelli, R; Ceccanti, B; Masciandaro, G

2013-07-01

The continuous stream of sediments, dredged from harbors and waterways for keeping shipping traffic efficiency, is a considerable ongoing problem recognized worldwide. This problem gets worse as most of the sediments dredged from commercial ports and waterways turn out to be polluted by a wide range of organic and inorganic contaminants. In this study, phytoremediation was explored as a sustainable reclamation technology for turning slightly-polluted brackish dredged sediments into a matrix feasible for productive use. To test this possibility, a phytoremediation experimentation was carried out in containers of about 0.7 m(3) each, filled with brackish dredged sediments contaminated by heavy metals and hydrocarbons. The sediments were pre-conditioned by adding an agronomic soil (30 % v/v) to improve their clayey granulometric composition, and by topping the mixture with high quality compost (4 kg m(-2)) to favour the initial adaptation of the selected vegetal species. The following plant treatments were tested: (1) Paspalum vaginatum, (2) Phragmites australis, (3) Spartium junceum + P. vaginatum, (4) Nerium oleander + P. vaginatum, (5) Tamarix gallica + P. vaginatum, and (6) unplanted control. Eighteen months after the beginning of the experimentation, all the plant species were found in healthy condition and well developed. Throughout the whole experiment, the monitored biological parameters (total microbial population and dehydrogenase activity) were generally observed as constantly increasing in all the planted sediments more than in the control, pointing out an improvement of the chemico-physical conditions of both microorganisms and plants. The concentration decrease of organic and inorganic contaminants (>35 and 20 %, respectively) in the treatments with plants, particularly in the T. gallica + P. vaginatum, confirmed the importance of the root-microorganism interaction in activating the decontamination processes. Finally, the healthy state of

Dredging in a changing scientific and regulatory environment

DOT National Transportation Integrated Search

2004-06-01

Dredging activities associated with commercial navigation have been the subject of substantial public policy conflict. At both the national and local levels, substantial concern has been expressed over the environmental consequences of the disposal o...

16. OPERATOR STAND. OPERATOR STOOD BETWEEN RAILINGS AND CONTROLLED DREDGING ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

16. OPERATOR STAND. OPERATOR STOOD BETWEEN RAILINGS AND CONTROLLED DREDGING OPERATIONS USING TWO LEVERS FROM CEILING, THREE LEVELS ON THE FLOOR, AND TWO FLOOR PEDDLES. RIGHT HAND CONTROLLED SHOT GUN SWINGER (BOOM MOVE TO RIGHT WHEN PUSHED FORWARD, LEFT WHEN PULLED BACK, AND, IF LUCKY, STOPPED WHEN IN CENTER POSITION). LEFT HAND CONTROLLED THROTTLE. FLOOR LEVER AND FLOOR PEDDLE ON LEFT CONTROLLED THE BACKING LINE FRICTION. MIDDLE LEVER AND PEDDLE, STUCK IN FLOOR CONTROLLED THE MAIN HOIST FRICTION. LEVER ON RIGHT CONTROLLED THE CYLINDER DRAIN VALVE. - Dredge CINCINNATI, Docked on Ohio River at foot of Lighthill Street, Pittsburgh, Allegheny County, PA

Oscillatory and Propagating Modes of Temperature Variability at the 3-3.5- and 4-4.5-yr Time Scales in the Upper Southwest Pacific Ocean.

NASA Astrophysics Data System (ADS)

Holbrook, Neil J.; Chan, Peter S.-L.; Venegas, Silvia A.

2005-03-01

This paper investigates oscillatory and propagating patterns of normalized surface and subsurface temperature anomalies (from the seasonal cycle) in the southwest Pacific Ocean using an extended empirical orthogonal function (EEOF) analysis. The temperature data (and errors) are from the Digital Atlas of Southwest Pacific upper Ocean Temperatures (DASPOT). These data are 3 monthly in time (January, April, July, and October), 2° × 2° in space, and 5 m in the vertical to 450-m depths. The temperature anomalies in the EEOF analysis are normalized by the objective mapping temperature errors at each grid point. They are also Butterworth filtered in the 3-7-yr band to examine interannual variations in the temperature field. The oscillating and propagating patterns of the modes are examined across four vertical levels: the surface, and 100-, 250-, and 450-m depths.The dominant mode EEOF (70% of the total variance of the filtered data) oscillates in a 4-4.5-yr quasi-periodic manner that is consistent with El Niño-Southern Oscillation (ENSO). Anomalies peak first at the surface in the subtropics between New Caledonia and Fiji (centered around 17°S, 177°E), then 6 months later in the tropical far west centered around the Solomon Islands (5°S, 153°-157°E), with a maximum at the base of the mixed layer (100 m) and upper thermocline (250 m), and then eastward in the northeast of the southwest Pacific region (0°-10°S, 160°E-180°). Mode 2 (25% variance of the filtered data) has a periodicity of 3-3.5 yr, with centers of action in all four vertical levels. The mode-2 patterns are consistent with variations in the subtropical gyre circulation, including the East Australian Current and its separation, and are continuous with the Tasman Front. Two spatial dipoles are apparent: (i) one in sea surface temperature (SST) at about 5°S, straddling west-east either side of the Solomon Islands, consistent with the classic Pacific-wide ENSO SST anomaly mode, and (ii) a

SRB Materials and Processes Assessment from Laboratory and Ocean Environmental Tests

NASA Technical Reports Server (NTRS)

1978-01-01

The Materials and Processes Laboratory evaluation of Solid Rocket Boosters (SRB) and Solid Rocket Motors (SRM) candidate material, both in-house and with ocean exposure tests at Panama City and Kennedy Space Center (KSC), Florida is presented. Early sample tests showed excellent seawater corrosion resistance for inconel 718 and titanium 6A1-4V alloys. Considerable corrosion and biofouling occurred with bare 2219-T87 aluminum. Subsequent tests conclusively demonstrated that epoxy coatings prevented corrosion of 2219-T87 aluminum as long as the coatings stays intact. The results and assessment of the series of ocean environmental tests that were conducted are also presented.

Ocean acidification alters the material properties of Mytilus edulis shells

PubMed Central

Fitzer, Susan C.; Zhu, Wenzhong; Tanner, K. Elizabeth; Phoenix, Vernon R.; Kamenos, Nicholas A.; Cusack, Maggie

2015-01-01

Ocean acidification (OA) and the resultant changing carbonate saturation states is threatening the formation of calcium carbonate shells and exoskeletons of marine organisms. The production of biominerals in such organisms relies on the availability of carbonate and the ability of the organism to biomineralize in changing environments. To understand how biomineralizers will respond to OA the common blue mussel, Mytilus edulis, was cultured at projected levels of pCO2 (380, 550, 750, 1000 µatm) and increased temperatures (ambient, ambient plus 2°C). Nanoindentation (a single mussel shell) and microhardness testing were used to assess the material properties of the shells. Young's modulus (E), hardness (H) and toughness (KIC) were measured in mussel shells grown in multiple stressor conditions. OA caused mussels to produce shell calcite that is stiffer (higher modulus of elasticity) and harder than shells grown in control conditions. The outer shell (calcite) is more brittle in OA conditions while the inner shell (aragonite) is softer and less stiff in shells grown under OA conditions. Combining increasing ocean pCO2 and temperatures as projected for future global ocean appears to reduce the impact of increasing pCO2 on the material properties of the mussel shell. OA may cause changes in shell material properties that could prove problematic under predation scenarios for the mussels; however, this may be partially mitigated by increasing temperature. PMID:25540244

REMEDIAL DREDGING AND EFFECTIVE ENVIRONMENTAL PROTECTION: EXAMPLES FROM THE NEW BEDFORD HARBOR, MA SUPERFUND SITE

EPA Science Inventory

Currently, there is an on-going national debate questioning whether remedial dredging can be conducted without causing environmental harm. Two common assertions are that: 1) dredging contaminated sediment will do more harm than good, and 2) natural processes will eventually mitig...

Dredging: An Annotated Bibliography on Operations, Equipment, and Processes. Installment 3. Revision.

DTIC Science & Technology

1985-01-01

four-pump ZULIA , is the largest earth moving machine in history. It was built specifically to clear an entrance to Lake Maracaibo . Four 32-inch dredge...Transverse Mercator (UTM), state plane, or geodetic coordinates. By placing shore stations at presurveyed locations, survey boat or dredge positions can... hand and earth movers) is presented along with discussion of the lock system and freshwater lakes that feed the Miraflores Locks on the Pacific end

Contextual view of ILWU Hall, facing southsouthwest, with ocean bank ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Contextual view of ILWU Hall, facing south-southwest, with ocean bank visible in the background - International Longshoremen's & Warehousemen's Union Hall, Naval Civil Engineering Laboratory, Port Hueneme Road, Port Hueneme, Ventura County, CA

Investigating Behaviour and Population Dynamics of Striped Marlin (Kajikia audax) from the Southwest Pacific Ocean with Satellite Tags

PubMed Central

Sippel, Tim; Holdsworth, John; Dennis, Todd; Montgomery, John

2011-01-01

Behaviour and distribution of striped marlin within the southwest Pacific Ocean were investigated using electronic tagging data collected from 2005–2008. A continuous-time correlated random-walk Kalman filter was used to integrate double-tagging data exhibiting variable error structures into movement trajectories composed of regular time-steps. This state-space trajectory integration approach improved longitude and latitude error distributions by 38.5 km and 22.2 km respectively. Using these trajectories as inputs, a behavioural classification model was developed to infer when, and where, ‘transiting’ and ‘area-restricted’ (ARB) pseudo-behavioural states occurred. ARB tended to occur at shallower depths (108±49 m) than did transiting behaviours (127±57 m). A 16 day post-release period of diminished ARB activity suggests that patterns of behaviour were affected by the capture and/or tagging events, implying that tagged animals may exhibit atypical behaviour upon release. The striped marlin in this study dove deeper and spent greater time at ≥200 m depth than those in the central and eastern Pacific Ocean. As marlin reached tropical latitudes (20–21°S) they consistently reversed directions, increased swimming speed and shifted to transiting behaviour. Reversals in the tropics also coincided with increases in swimming depth, including increased time ≥250 m. Our research provides enhanced understanding of the behavioural ecology of striped marlin. This has implications for the effectiveness of spatially explicit population models and we demonstrate the need to consider geographic variation when standardizing CPUE by depth, and provide data to inform natural and recreational fishing mortality parameters. PMID:21695132

Effects of dredging operations on the demersal fish fauna of a South American tropical-subtropical transition estuary.

PubMed

Barletta, M; Cysneiros, F J A; Lima, A R A

2016-07-01

Changes in the environment and in the composition of fish assemblages in the Paranaguá Estuary (South Brazil) were assessed by comparisons made before, during and after dredging operations, in the same months and areas studied in the previous year. Interactions between year and month were observed for salinity. During the dredging year fish total density was 2 individuals m(-2) and with a total biomass of 104 g m(-2) (among 31 species captured). For the same period the year before, 0·3 individuals m(-2) and 3 g m(-2) were captured (38 species). The number of species showed significant time v. month interactions, assuming that fish species composition varied for both year and month. Total mean density and biomass showed significant differences for interaction time v. month, and density and biomass in the dredging month September 2001 in the main channel were scientifically different from other months. Interaction times v. area were significant for Cathorops spixii (increased biomass), Aspistor luniscutis (increased density), Menticirrhus americanus (decreased biomass) and Cynoscion leiarchus (decreased density and biomass). This suggests that during the dredging process there is a change in the structure of the demersal fish assemblage. The impact (damage and mortality) induced by dredging on the macrobenthic animals along the dredge path attracted adults of C. spixii that reached densities 10 times greater than in the year before. On the other hand, sciaenid species practically disappeared. To contribute to the conservation of the estuarine fish fauna, and maintain fisheries production of the Paranaguá Estuary and surrounding areas, it is recommended that, dredging should be done from the late rainy season to the early dry season. Decisions must take into account the ecological cycles of socio-economically important fish species and prioritize the safe disposal of dredged spoils. © 2016 The Fisheries Society of the British Isles.

Short-term environmental impact of clam dredging in coastal waters (south of Portugal): chemical disturbance and subsequent recovery of seabed.

PubMed

Falcão, M; Gaspar, M B; Caetano, M; Santos, M N; Vale, C

2003-12-01

The physical and chemical changes in sediment and near bottom water caused by clam dredging were examined during July and September 1999, at two locations Vilamoura (VL) and Armona (AR), south coast of Portugal. Sediment cores and near bottom water were collected simultaneously before dredging (control samples) and within short time intervals (min-h) after dredging. After dredging operations, microphytobenthos coming from the path were accumulated in the re-worked sediment (ridge). Chlorophyll a in superficial sediment increased from 1.2 microg x g(-1) before dredging to 1.7 microg x g(-1) after dredging and these higher values remained for a few hours. However, the expected increase of chlorophyll a in near bottom water due to re-suspension was not observed. After sediment disturbance an instantaneous sorption of phosphorus onto iron oxides occurred in the upper sediment layers (from 2 to 3 micromol x g(-1) before dredging to 4-5 micromol x g(-1) after dredging). A microcosm experiment showed that after sediment disturbance HPO(4)(2-) dissolved in pore water decreased from 40 to 10 microM being simultaneously sorbed onto iron oxides formed in the top layer of sediment. The ammonium, nitrates, organic nitrogen, phosphate and silicate dissolved in pore water decreased immediately after dredging activity and simultaneously an increase in near bottom water was sporadically observed. Generally, the re-establishment of seabed was reached within a short time (min-h), at both stations (VL and AR).

78 FR 38975 - Environmental Impacts Statements; Notice of Availability

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-28

... Everglades Harbor Navigation Improvements, Comment Period Ends: 08/13/2013, Contact: Terri Jordan-Sellers 904... Channel Ocean Dredged Material Disposal Site West, Pursuant to Section 102(c) of the Marine Protection...

Potential contaminants at a dredged spoil placement site, Charles City County, Virginia, as revealed by sequential extraction

PubMed Central

Tang, Jianwu; Whittecar, G Richard; Johannesson, Karen H; Daniels, W Lee

2004-01-01

Backfills of dredged sediments onto a former sand and gravel mine site in Charles City County, VA may have the potential to contaminate local groundwater. To evaluate the mobility of trace elements and to identify the potential contaminants from the dredged sediments, a sequential extraction scheme was used to partition trace elements associated with the sediments from the local aquifer and the dredged sediments into five fractions: exchangeable, acidic, reducible, oxidizable, and residual phases. Sequential extractions indicate that, for most of the trace elements examined, the residual phases account for the largest proportion of the total concentrations, and their total extractable fractions are mainly from reducible and oxidizable phases. Only Cd, Pb, and Zn have an appreciable extractable proportion from the acidic phase in the filled dredged sediments. Our groundwater monitoring data suggest that the dredged sediments are mainly subject to a decrease in pH and a series of oxidation reactions, when exposed to the atmosphere. Because the trace elements released by carbonate dissolution and the oxidation (e.g., organic matter degradation, iron sulfide and, ammonia oxidation) are subsequently immobilized by sorption to iron, manganese, and aluminum oxides, no potential contaminants to local groundwater are expected by addition of the dredged sediments to this site.

78 FR 29687 - Ocean Dumping; Atchafalaya-West Ocean Dredged Material Disposal Site Designation

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-21

..., including the Department of Defense. Industry and general public Port authorities, marinas and harbors... owning and/or responsible for ports, harbors, and/or berths, Government agencies requiring disposal of... the ODMDS-East. Background suspended solids concentrations were approximately 100 mg/L and currents...

Faunal and vegetation monitoring in response to harbor dredging in the Port of Miami

USGS Publications Warehouse

Daniels, Andre; Stevenson, Rachael; Smith, Erin; Robblee, Michael

2018-04-11

Seagrasses are highly productive ecosystems. A before-after-control-impact (BACI) design was used to examine effects of dredging on seagrasses and the animals that inhabit them. The control site North Biscayne Bay and the affected site Port of Miami had seagrass densities decrease during both the before, Fish and Invertebrate Assessment Network 2006-2011, and after, Faunal Monitoring in Response to Harbor Dredging 2014-2016, studies. Turbidity levels increased at North Biscayne Bay and Port of Miami basins during the Faunal Monitoring in Response to Harbor Dredging study, especially in 2016. Animal populations decreased significantly in North Biscayne Bay and Port of Miami in the Faunal Monitoring in Response to Harbor Dredging study compared to the Fish and Invertebrate Assessment Network study. Predictive modeling shows that numbers of animal populations will likely continue to decrease if the negative trends in seagrass densities continue unabated. There could be effects on several fisheries vital to the south Florida economy. Additional research could determine if animal populations and seagrass densities have rebounded or continued to decrease.

Evolution of mud-capped dredge pits following excavation: sediment trapping and slope instability

NASA Astrophysics Data System (ADS)

Obelcz, J.; Xu, K.; Bentley, S. J.; Li, C.; Miner, M. D.; O'Connor, M. C.; Wang, J.

2016-02-01

Many fluvial channels incised the Northern Gulf of Mexico inner continental shelf during the late Quaternary. Mud-capped dredge pits (MCDPs), which are generally elongate and deep (8-10 m) excavations, target sandy fluvial channel deposits for coastal restoration projects. The morphological evolution of dredge excavations in noncohesive sandy substrate is well studied, but MCDPs have up to a several-meter-thick veneer of Holocene shelf mud overlying sandy channel deposits. This stratigraphy is hypothesized to result in more complex post-dredge morphology than pit walls simply slumping to the angle of repose shortly after excavation. Numerical modeling of MCDP post-dredge response conducted prior to excavation indicates pit walls may retrogressively fail, which is accounted for in pit design by assigning no-dredge setback buffers from pipelines or cultural and environmental resources. To validate model results and test effectiveness of setback buffers, a geophysical survey of the Sandy Point MCDP (20 km west of the Mississippi River Delta in 10m deep water), where 1.7 million m3 of sandy sediment was excavated in 2012, was conducted May 2015. A total of 84 line-km of high-resolution chirp subbottom and a 27 km2 grid of swath bathymetry and sidescan sonar were collected. The data indicate the dredge pit walls are differentially slumping, with the western pit wall in a more active state of failure than the eastern wall. The western failures morphologically resemble features observed along the muddy Mississippi River Delta Front at water depths of 20-100 m, including bowl-shaped collapse failures and retrogressive stair-stepped slumps; these failures may play a key role in evaluating the distance of setback buffer zone to pipelines. These features indicate the cohesive mud overlying the sandy infill has a prominent role in pit wall stability. A 0.5-1 m thick acoustically transparent package overlies the entire pit floor (interpreted as a possible fluid mud layer

Recycled material availability in Maryland - a synthesis study.

DOT National Transportation Integrated Search

2016-10-01

There is growing interest in using recycled materials in highway construction nationwide. The research study focused : on four types of recycled materials: recycled concrete aggregate (RCA), reclaimed asphalt pavement (RAP), dredged : materials, and ...

Phytoremediation of metals contaminated dredged sediments: Use of synthetic chelates in metals phytoextraction

NASA Astrophysics Data System (ADS)

Sahut, C.; Geniaut, G.; Lillo, M. P.

2003-05-01

(in Times 10 points) The waterways maintenance leads to a large volume of dredged polluted sediments, to be disposed of, every year. As the economic disposal of dredged sediment is a single line along the stream they can behave as a sink of pollutant and a migration in the environment is observed. Chelate-enhanced phytoremediation has been proposed as an effective tool for the extraction of heavy metals from dredged sediment by plants. Lysimeters studies were conducted to study the phytoremediation of sediments with EDTA and lactic acid used as synthetic chelators. EDTA appeared to enhance metal solubility by plant uptake did not increase accordingly. Futhermore EDTA enhance metal leaching which could lead 10 groungwater pollution. To prevent these unwanted side-effects, careful management of phytoremediation and of the use of EDTA seems necessary.

Environmental Windows Associated with Dredging Operations

DTIC Science & Technology

1998-12-01

Unspecified species Mercenaria mercenaria MVR, LRL, MVS NAN Hard Clam Soft Shell Clam Mya arenaria NAE, NAB Surf Clam Spisula solidissima NAN Eastern...nearly 100 percent. This was followed closely by the North Atlantic and South Atlantic Divisions, with approximately 85 percent of all dredging projects... Atlantic Division (NAD) South Atlantic Division (SAD) Baltimore District (NAB) Charleston District (SAC) New England District (NAE) Jacksonville District

78 FR 59677 - Environmental Impacts Statements; Notice of Availability

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-27

..., Designation of the Atchafalaya River Bar Channel Ocean Dredged Material Disposal Site, Review Period Ends: 10.../2013, Contact: Paul Bradford 406-293-6211. EIS No. 20130282, Final EIS, USFS, WY, Clinker Mining...

Successful control of internal phosphorus loading after sediment dredging for 6years: A field assessment using high-resolution sampling techniques.

PubMed

Chen, Musong; Cui, Jingzhen; Lin, Juan; Ding, Shiming; Gong, Mengdan; Ren, Mingyi; Tsang, Daniel C W

2018-03-01

The effectiveness of sediment dredging for the control of internal phosphorus (P) loading, was investigated seasonally in the eutrophic Lake Taihu. The high-resolution dialysis (HR-Peeper) and diffusive gradients in thin films (DGT) techniques were used to measure the concentrations of soluble Fe(II) and soluble reactive P (SRP) as well as DGT-labile Fe/P in the non-dredging and post-dredging sediments. The P resupply kinetics from sediment solids were interpreted using DGT Induced Fluxes in Sediments (DIFS) modeling. The results showed no obvious improvement in water and sediment quality after dredging for 6years, due to their geographical proximity (a line distance of approximately 9km). However, dredging significantly decreased the concentrations of soluble Fe(II)/SRP and DGT-labile Fe/P in sediments, with effects varying at different depths below the sediment-water interface; More pronounced effects appeared in January and April. The diffusive flux of pore water SRP from sediments decreased from 0.746, 4.08 and 0.353mg/m 2 /d to 0.174, 1.58 and 0.048mg/m 2 /d in April, July and January, respectively. DIFS modeling indicated that the P retention capability of sediment solids was improved in April in post-dredging site. Positive correlations between pore water soluble Fe(II) and SRP as well as between DGT-labile Fe and P, reflect the key role of Fe redox cycling in regulating dredging effectiveness. This effect is especially important in winter and spring, while in summer and autumn, the decomposition of algae promoted the release of P from sediments and suppressed dredging effectiveness. Overall, the high-resolution HR-Peeper and DGT measurements indicated a successful control of internal P loading by dredging, and the post-dredging effectiveness was suppressed by algal bloom. Copyright © 2017 Elsevier B.V. All rights reserved.

Ocean acidification alters the material properties of Mytilus edulis shells.

PubMed

Fitzer, Susan C; Zhu, Wenzhong; Tanner, K Elizabeth; Phoenix, Vernon R; Kamenos, Nicholas A; Cusack, Maggie

2015-02-06

Ocean acidification (OA) and the resultant changing carbonate saturation states is threatening the formation of calcium carbonate shells and exoskeletons of marine organisms. The production of biominerals in such organisms relies on the availability of carbonate and the ability of the organism to biomineralize in changing environments. To understand how biomineralizers will respond to OA the common blue mussel, Mytilus edulis, was cultured at projected levels of pCO2 (380, 550, 750, 1000 µatm) and increased temperatures (ambient, ambient plus 2°C). Nanoindentation (a single mussel shell) and microhardness testing were used to assess the material properties of the shells. Young's modulus (E), hardness (H) and toughness (KIC) were measured in mussel shells grown in multiple stressor conditions. OA caused mussels to produce shell calcite that is stiffer (higher modulus of elasticity) and harder than shells grown in control conditions. The outer shell (calcite) is more brittle in OA conditions while the inner shell (aragonite) is softer and less stiff in shells grown under OA conditions. Combining increasing ocean pCO2 and temperatures as projected for future global ocean appears to reduce the impact of increasing pCO2 on the material properties of the mussel shell. OA may cause changes in shell material properties that could prove problematic under predation scenarios for the mussels; however, this may be partially mitigated by increasing temperature. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

The forcing of monthly precipitation variability over Southwest Asia during the Boreal cold season

USGS Publications Warehouse

Hoell, Andrew; Shukla, Shraddhanand; Barlow, Mathew; Cannon, Forest; Kelley, Colin; Funk, Christopher C.

2015-01-01

Southwest Asia, deemed as the region containing the countries of Afghanistan, Iran, Iraq and Pakistan, is water scarce and receives nearly 75% of its annual rainfall during8 the boreal cold season of November-April. The forcing of Southwest Asia precipitation has been previously examined for the entire boreal cold season from the perspective of climate variability originating over the Atlantic and tropical Indo-Pacific Oceans. Here, we examine the inter-monthly differences in precipitation variability over Southwest Asia and the atmospheric conditions directly responsible in forcing monthly November-April precipitation. Seasonally averaged November-April precipitation over Southwest Asia is significantly correlated with sea surface temperature (SST) patterns consistent with Pacific Decadal Variability (PDV), the El Nino-Southern Oscillation (ENSO) and the warming trend of SST (Trend). On the contrary, the precipitation variability during individual months of November-April are unrelated and are correlated with SST signatures that include PDV, ENSO and Trend in different combinations. Despite strong inter-monthly differences in precipitation variability during November- April over Southwest Asia, similar atmospheric circulations, highlighted by a stationary equivalent barotropic Rossby wave centered over Iraq, force the monthly spatial distributions of precipitation. Tropospheric waves on the eastern side of the equivalent barotropic Rossby wave modifies the flux of moisture and advects the mean temperature gradient, resulting in temperature advection that is balanced by vertical motions over Southwest Asia. The forcing of monthly Southwest Asia precipitation by equivalent barotropic Rossby waves is different than the forcing by baroclinic Rossby waves associated with tropically-forced-only modes of climate variability.

Response of the seagrass Halophila ovalis to altered light quality in a simulated dredge plume.

PubMed

Strydom, Simone; McMahon, Kathryn; Lavery, Paul S

2017-08-15

Seagrass meadows are globally threatened, largely through activities that reduce light quantity (photosynthetic photon flux density) such as dredging. However, these activities can simultaneously alter the spectral quality of light. Previous studies showed that Halophila ovalis seagrass productivity is reduced under monochromatic yellow/green light, wavelengths associated with dredge plumes, but it is unclear how they respond to spectra produced by real dredging projects. We simultaneously subjected adult H. ovalis plants to altered light quality and quantity simulating a real commercial dredging operation (15mgL -1 TSS, 50 and 200μmol photonsm -2 s -1 ). There was a significant effect of reduced light quantity on physiological and morphological variables and a significant effect of light quality on the pigment antheraxanthin. The lack of effect of light quality on growth indicates that while seagrass are sensitive to changes in light quality, natural- and anthropogenic-driven changes may not always be sufficient to produce strong effects on H. ovalis. Copyright © 2017 Elsevier Ltd. All rights reserved.

Evaluation of simulated dredging to control internal phosphorus release from sediments: Focused on phosphorus transfer and resupply across the sediment-water interface.

PubMed

Yu, Juhua; Ding, Shiming; Zhong, Jicheng; Fan, Chengxin; Chen, Qiuwen; Yin, Hongbin; Zhang, Lei; Zhang, Yinlong

2017-08-15

Sediment dredging is an effective restoration method to control the internal phosphorus (P) loading of eutrophic lakes. However, the core question is that the real mechanism of dredging responsible for sediment internal P release still remains unclear. In this study, we investigated the P exchange across the sediment-water interface (SWI) and the internal P resupply ability from the sediments after dredging. The study is based on a one-year field simulation study in Lake Taihu, China, using a Rhizon soil moisture sampler, high-resolution dialysis (HR-Peeper), ZrO-Chelex diffusive gradients in thin film (ZrO-Chelex DGT), and P fractionation and adsorption isotherm techniques. The results showed low concentration of labile P in the pore water with a low diffusion potential and a low resupply ability from the sediments after dredging. The calculated flux of P from the post-dredged sediments decreased by 58% compared with that of non-dredged sediments. Furthermore, the resupply in the upper 20mm of the post-dredged sediments was reduced significantly after dredging (P<0.001). Phosphorus fractionation analysis showed a reduction of 25% in the mobile P fractions in the post-dredged sediments. Further analysis demonstrated that the zero equilibrium P concentration (EPC 0 ), partitioning coefficient (K p ), and adsorption capacity (Q max ) on the surface sediments increased after dredging. Therefore, dredging could effectively reduce the internal P resupply ability of the sediments. The reasons for this reduction are probably the lower contributions of mobile P fractions, higher retention ability, and the adsorption capacity of P for post-dredged sediments. Overall, this investigation indicated that dredging was capable of effectively controlling sediment internal P release, which could be ascribed to the removal of the surface sediments enriched with total phosphorus (TP) and/or organic matter (OM), coupled with the inactivation of P to iron (Fe) (hydr)oxides in the upper

Optimal dredge fleet scheduling within environmental work windows.

DOT National Transportation Integrated Search

2016-09-15

The U.S. Army Corps of Engineers (USACE) annually spends more than 100 million dollars on dredging hundreds of navigation projects on more than 12,000 miles of inland and intra-coastal waterways. Building on previous work with USACE, this project exp...

Environmental Risk Assessment of dredging processes - application to Marin harbour (NW Spain)

NASA Astrophysics Data System (ADS)

Gómez, A. G.; García Alba, J.; Puente, A.; Juanes, J. A.

2014-04-01

A methodological procedure to estimate the environmental risk of dredging operations in aquatic systems has been developed. Environmental risk estimations are based on numerical models results, which provide an appropriated spatio-temporal framework analysis to guarantee an effective decision-making process. The methodological procedure has been applied on a real dredging operation in the port of Marin (NW Spain). Results from Marin harbour confirmed the suitability of the developed methodology and the conceptual approaches as a comprehensive and practical management tool.

Processes of physical change to the seabed and bivalve recruitment over a 10-year period following experimental hydraulic clam dredging on Banquereau, Scotian Shelf

NASA Astrophysics Data System (ADS)

Gilkinson, K.; King, E. L.; Li, M. Z.; Roddick, D.; Kenchington, E.; Han, G.

2015-01-01

A previous study on the effects of experimental hydraulic clam dredging on seabed habitat and commercial bivalve populations revealed a lack of recovery after a 3-year post-dredging period (1998-2001) on a deep (65-75 m) offshore sandy bank on the Scotian Shelf, Canada. Follow-up sidescan sonar surveys were carried out 5 and 10 years after dredging (2003, 2008) in order to identify long-term processes of seabed recovery. Grab sampling was carried out 10 years after dredging to identify post-dredging commercial bivalve recruitment. Changes in the seafloor, including dredge tracks, were documented with a series of 7 sidescan sonar surveys between 1998 and 2008. A sediment mobility model was constructed based on modeled tidal current and hindcast wave data over this time period to quantify natural seabed disturbance and interpret changes to the dredge tracks mapped by sidescan sonar surveys. The model indicated that tidal currents had minimal effect on sediment mobilization. The main driving force associated with re-working of surficial sediments as evidenced by deterioration of dredge tracks in sonograms was annual fall/winter storms. While the annual frequency of storms and associated wave heights was variable, the observations and sediment mobility calculations suggest that the most influential variable is the magnitude of individual large storms, specifically storms with a significant wave height of ∼11 m. These storms are capable of generating mobile sediment layers of 20-30 cm thickness, equivalent to the dredge blade cutting depth. It appears that, with minor exceptions, sediment properties have returned to pre-dredging conditions 10 years after dredging in this habitat. Based on known age-length relationships, the four commercial bivalve species showed very low recruitment at the experimental site over the 10-year post-dredging period. However, this is unlikely due to a dredging effect since a similar pattern was observed in non-dredged areas.

Hydrogeologic framework, hydrology, and water quality in the Pearce Creek Dredge Material Containment Area and vicinity, Cecil County, Maryland, 2010-11

USGS Publications Warehouse

Dieter, Cheryl A.; Koterba, Michael T.; Zapecza, Otto S.; Walker, Charles W.; Rice, Donald E.

2013-01-01

In 2009, to support an evaluation of the feasibility of reopening the Pearce Creek Dredge Material Containment Area (DMCA) in Cecil County, Maryland, for dredge-spoil disposal, the U.S. Geological Survey (USGS) began to implement a comprehensive study designed to improve the understanding of the hydrogeologic framework, hydrology, and water quality of shallow aquifers underlying the DMCA and adjacent communities, to determine whether or not the DMCA affected groundwater quality, and to assess whether or not groundwater samples contained chemical constituents at levels greater than maximum allowable or recommended levels established by the U.S. Environmental Protection Agency Safe Drinking Water Act. The study, conducted in 2010-11 by USGS in cooperation with the U.S. Army Corps of Engineers, included installation of observation wells in areas where data gaps led earlier studies to be inconclusive. The data from new wells and existing monitoring locations were interpreted and show the DMCA influences the groundwater flow and quality. Groundwater flow in the two primary aquifers used for local supplies-the Magothy aquifer and upper Patapsco aquifer (shallow water-bearing zone)-is radially outward from the DMCA toward discharge areas, including West View Shores, the Elk River, and Pearce Creek Lake. In addition to horizontal flow outward from the DMCA, vertical gradients primarily are downward in most of the study area, and upward near the Elk River on the north side of the DMCA property, and the western part of West View Shores. Integrating groundwater geochemistry data in the analysis, the influence of the DMCA is not only a source of elevated concentrations of dissolved solids but also a geochemical driver of redox processes that enhances the mobilization and transport of redox-sensitive metals and nutrients. Groundwater affected by the DMCA is in the Magothy aquifer and upper Patapsco aquifer (shallow water-bearing zone). Based on minimal data, the water quality

One new genus and three new species of deep-sea nematodes (Nematoda: Microlaimidae) from the Southwest Pacific Ocean and Ross Sea.

PubMed

Leduc, Daniel

2016-02-11

New deep-sea nematodes of the family Microlaimidae are described from the Southwest Pacific Ocean and Ross Sea. Microlaimus korari n. sp. is characterised by annulated cuticle with longitudinal bars, round amphideal aperture slightly smaller than the cryptospiral amphideal fovea, spacious and heavily cuticularised buccal cavity with large dorsal tooth and right subventral tooth situated anteriorly relative to left subventral tooth, slender spicules 4.4 cloacal body diameters long, and gubernaculum 1.2 cloacal body diameters long with laterally curved distal end and swollen proximal end. Bolbolaimus tongaensis n. sp. is characterised by annulated cuticle with longitudinal bars, oval amphideal aperture and cryptocircular amphideal fovea situated between cephalic setae and only partially surrounded by cuticle annulations, and short spicules cuticularised along dorsal edge and at proximal end and with swollen portion near proximal end. Maragnopsia n. gen. is characterised by a minute, non-cuticularised mouth cavity without teeth, an elongated posterior pharyngeal bulb more than twice as long as it is wide, a single outstretched testis, and a conico-cylindrical tail 13-16 anal body diameters long. A list of all 83 valid Microlaimus species is provided. The present study provides the first microlaimid species records from deep-sea habitats (> 200 m depth) in the Southwest Pacific and Ross Sea. The presence of M. korari n. sp. on both the continental slope of New Zealand and Ross Sea abyssal plain suggests that this species has a wide geographical and depth distribution. However, molecular analyses will be required to confirm the identity of these two geographically disparate populations.

Localised and limited impact of a dredging operation on coral cover in the northwestern lagoon of New Caledonia.

PubMed

Adjeroud, Mehdi; Gilbert, Antoine; Facon, Mathilde; Foglia, Marion; Moreton, Benjamin; Heintz, Tom

2016-04-15

We report here an interannual survey (2006-2012) of coral cover in the northwestern lagoon of New Caledonia, to assess the impact of an important dredging operation (August 2008-February 2010) associated with the construction of the largest nickel mining site in the Pacific. A BACI (Before-After Control-Impact) analysis failed to detect any significant interaction between period (before, during, and after dredging) and the category of the stations (impact vs. control). Among the 31 stations surveyed, only seven showed decreasing coral cover during the study period, mainly due to a decline in Acroporidae. However, the relationship between the dredging and this decrease was highly plausible only for one station, situated 0.9km from the dredging site. High hydrodynamism in the study area, the abundance of resistant corals and efficient protective measures during the dredging operation might explain these localised and limited impacts. Copyright © 2016 Elsevier Ltd. All rights reserved.

Fe-Ti-oxide textures and microstructures in shear zones from oceanic gabbros at Atlantis Bank, Southwest Indian Ridge

NASA Astrophysics Data System (ADS)

Till, Jessica; Morales, Luiz F. G.; Rybacki, Erik

2016-04-01

Ocean drilling expeditions at several oceanic core complexes formed at slow- and ultra-slow-spreading ridges have recovered cores containing numerous zones of oxide-rich gabbros containing ilmenite and magnetite. In these cores, high modal concentrations of Fe-Ti-oxides are systematically associated with high-temperature plastic deformation features in silicates. We present observations of Fe-Ti-oxide mineral structures and textural characteristics from a series of oxide-rich shear zones from Atlantis Bank (ODP Site 735B) on the Southwest Indian Ridge aimed at determining how oxide mineral abundances relate to strain localization. Fe-Ti-oxide minerals in undeformed oxide gabbros and in highly deformed samples from natural shear zones generally have morphologies characteristic of crystallized melt, including highly cuspate grains and low dihedral angles. Anisotropy of magnetic susceptibility in oxide-rich shear zones is very strong, with fabrics mainly characterized by strong magnetic foliations parallel to the macroscopic foliation. Crystallographic preferred orientations (CPO) in magnetite are generally weak, with occasionally well-defined textures. Ilmenite typically displays well-developed CPOs, however, the melt-like ilmenite grain shapes indicate that at least part of the crystallographic texture results from oriented ilmenite growth during post-deformation crystallization. The oxides are hypothesized to have initially been present as isolated pockets of trapped melt (intercumulus liquid) in a load-bearing silicate framework. Progressive plastic deformation of silicate phases at high-temperature mainly produced two features: (i) elongated melt pockets, which crystallized to form strings of opaque minerals and (ii), interconnected networks of melt regions. The latter lead to intense strain localization of the rock, which appears as oxide-rich mylonites in the samples. In some samples, abundant low-angle grain boundaries in both magnetite and ilmenite suggest

Synopsis of research needs workshop: Development of leach tests for contaminated dredged material held in Baton Rouge, Louisiana on 23-24 June 1988. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1990-02-01

This report presents the findings of a research needs workshop on the development of leach tests for contaminated dredged material, held 23-24 June 1988 in Baton Rouge, LA. The workshop was hosted by the Louisiana Water Resources Research Institute and the US Army Engineer Waterways Experiment Station (WES). The workshop participants reviewed results of research on test procedures developed by the WES and provided eight recommendations for directing future research in this area. Workshop panelists were of the opinion that research conducted to date was good and generally validated the basic technical approaches suggested by the 1984 Corps leachate qualitymore » working group. However, the consensus was that much research remains to be done before a leach test (s) will be available for routine use.« less

Alkalic Basalt in Ridge Axis of 53˚E Amagmatic Segment Center, Southwest Indian Ridge

NASA Astrophysics Data System (ADS)

Zhou, H.; Wang, J.; Liu, Y.; Ji, F.; Dick, H. J.

2014-12-01

Mid-ocean ridge basalt (MORB) is key tracer of composition and process in the mantle. It is interesting to notice that some alkalic basalts occur in amagmatic spreading center of ultraslow spreading ridges, for examples, 9-16˚E of the Southwest Indian ridge (Standish et al., 2008) and Lena Trough of Arctic Ocean (Snow et al., 2011). The latter is interpreted as the result of the pre-existence of continental transform fault or the especially cold thermal structure of ancient continental lithosphere. 53˚E segment, east of the Gallieni transform fault, was discovered as an amagmatic segment (Zhou and Dick, 2013). On both sides of the ridge axis, peridotites with a little gabbro are exposed in an area more than 3200 km2. Basalts exist in the southern portion of 53˚E segment, indicating the transformation from magmatic to amagmatic spreading about 9.4 million years ago. In April of 2014, Leg 4 of the RV Dayang Yihao cruise 30, basaltic glasses was dredged at one location (3500 m water depth) in the ridge axis of 53˚E segment center. It is shown by electric probe analysis that the samples have extremely high sodium content (4.0-4.49 wt% Na­2O ), relative higher potassium content (0.27-0.32 wt% K2O) and silica (50.67-51.87 wt% SiO2), and lower MgO content (5.9-6.4 wt% MgO). Mg-number is 0.55-0.59. It is distinctly different from the N-MORB (2.42-2.68 wt% Na2O, 0.03-0.06 wt% K2O, 48.6-49.6 wt% Si2O, 8.8-9.0 wt% MgO, Mg-numbers 0.63) distributed in the 560-km-long supersegment, west of the Gallieni transform fault, where the active Dragon Flag hydrothermal field was discovered at 49.6˚E in 2007. The reasons for the alkalic basalt in the ridge axis of 53˚E amagmatic segment center, either by low melting degree of garnet stability field, by melting from an ancient subcontinental lithospheric mantle, or by sodium-metasomatism or even other mantle processes or their combination in the deep mantle, are under further studies.

Looking Southwest at Southwest End of Erbia Building Showing Typical ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Looking Southwest at Southwest End of Erbia Building Showing Typical Wall and Roof Juncture Including a Recycling Furnace - Hematite Fuel Fabrication Facility, Erbia Plant, 3300 State Road P, Festus, Jefferson County, MO

An experimental study on dredge spoil of estuarine sediments in the bay of seine (France): A morphosedimentary assessment

NASA Astrophysics Data System (ADS)

Marmin, Stella; Lesueur, Patrick; Dauvin, Jean Claude; Samson, Sandrine; Tournier, Patrice; Gallicher Lavanne, Albert; Dubrulle-Brunaud, Carole; Thouroude, Coralie

2016-03-01

Studies on the consequences of dredging on estuarine morphology and its sedimentary dynamics are common, but the impacts of dumping dredge spoil in coastal open settings are rarely found in scientific literature. An experimental study was conducted over the period 2012-2013 to monitor the physical impacts of dredged material dumped at two adjacent sites (one million cubic metres at each) on the inner shelf of the Bay of Seine in France (eastern part of the English Channel, La Manche). As recently reinforced in the EU Marine Strategy Framework Directive (MSFD), knowledge on the location and intensity of human impacts (e.g. on marine ecosystems) is critical for effective marine management and conservation. So, two methods of disposition were tested to evaluate the impacts of dumping on the environment and thus propose recommendations for future dumping. The strategy is based on a Before-After-Control-Impact (BACI) approach, in which the spatio-temporal variability was studied by analysing the morphological and sedimentological characteristics over a period of 28 months, from November 2011 to April 2014, also including recovery of the seafloor after cessation of the dumping activities. The first experimental dumping operation (MASED) was carried out regularly for 8 months at a single point and generating a conical deposit of 5 m in height, while the second dumping (MABIO) lasted for 12 months involving four steps in the dumping process. In the second case, a wider area was covered, leading to the formation of a smaller deposit of 2 m in height. The dumped deposits consisted of muddy fine sand, whereas the inner shelf seafloor in this area is covered with fine to medium sand. As a result, muddy fine sand accumulated at or near the two dumping sites, with a maximum mud (i.e. particles<63 μm or>4 Φ) content of 50% compared to<5% before dumping operations. Videos obtained from a LVB200 Seabotix ROV, highlighted the heterogeneity of the sea floor around the dumping areas

Olivine-Rich Troctolite from the Southwest Indian Ridge: Constrains on Melt-Rock Reaction beneath Mid-Ocean Ridges

NASA Astrophysics Data System (ADS)

Yang, A. Y.

2017-12-01

The origin of olivine-rich troctolite, which have been recovered in the plutonic sample suites from the fast-spreading East Pacific Rise, and slow-spreading Mid-Atlantic Ridge and Central Indian Ridge, has been highly debated. They can form either by fractionation of primitive mid-ocean ridge basalt (MORB) melts or by melt migrating through pre-existing (possibly mantle) olivine matrix, thus recording valuable information of magmatic process at mantle-crust transition. This study presents in situ major and trace element study on the olivine-rich troctolite first reported from the ultraslow-spreading Southwest Indian Ridge (SWIR), together with a series of samples from peridotite, gabbro to basalt from an amagmatic segment at 53°E during Dayangyihao Cruises, to investigate the magmatic processes occurred at mantle-crust transition and origin of olivine-rich troctolite. The olivine in the troctolite shows cumulate textures with interstitial clinopyroxene, plagioclase and minor spinel, which is cross-cut by an olivine gabbro vein. Olivine in the troctolite show only mildly decreasing NiO contents (from 0.31-0.25 wt.%) with decreasing Fo (from 86 to 81), and even olivine in the gabbro have NiO up to 0.24 wt.% with Fo of 75. The Fo vs. Ni correlation of olivine is shifted to uniquely higher NiO at a certain Fo compared to the trends defined by either olivine from other lower oceanic crust (LOC) cumulates worldwide or olivine compositions from classic fractionation model for primitive MORB magma. Interstitial clinopyroxene in the troctolite have high Mg# (88-90), Cr2O3 (up to 1.51 wt.%) and TiO2 contents (up to 1.01 wt.%) with Eu/Eu* from 0.4-0.6. Such high-Ti-Cr-Mg# clinopyroxene is rare among global LOC cumulates, and cannot result from simple fractionation of MORB magma. The mineral compositions in the olivine-rich troctolite could be modeled by reaction between a primitive olivine matrix and a highly evolved melt (with 2.4 wt.% TiO2), and such a melt composition is

A risk-informed decision framework for setting environmental windows for dredging projects.

PubMed

Suedel, Burton C; Kim, Jongbum; Clarke, Douglas G; Linkov, Igor

2008-09-15

Sediment dredging is necessary to sustain navigation infrastructure in ports and harbor areas. In the United States alone between 250 and 300 million cubic yards of sediment are dredged annually. Dredging activities may cause stress on aquatic biota by locally increasing turbidity and suspended sediment concentrations, physically disturbing habitat by elevated sedimentation rates, interfering in migratory behaviors, and hydraulically entraining bottom dwelling organisms. Environmental windows are a management practice used to alleviate such stresses on resident and transient biota by placing temporal restrictions on the conduct of dredging operations. Adherence to environmental windows can significantly inflate costs for project sponsors and local stakeholders. Since their inception following passage of NEPA in 1969 the process for setting environmental windows has not followed structured procedures and represents an example of the difficulty inherent in achieving a balance between biological resource protection and cost-effective construction and maintenance of navigation infrastructure. Recent developments in the fields of risk assessment for non-chemical stressors as well as experience in implementing structured risk-informed decision-making tools for sediment and natural resource management are summarized in this paper in relation to setting environmental windows. Combining risk assessment and multi-criteria decision analysis allows development of a framework for an objective process consistent with recommendations by the National Academy of Sciences for setting environmental windows. A hypothetical application of the framework for protection of Pacific herring (Clupea pallasii) in San Francisco Bay is discussed.

The semi-brittle to ductile transition in peridotite on oceanic faults: mechanisms and P-T condition

NASA Astrophysics Data System (ADS)

Prigent, C.; Warren, J. M.; Kohli, A. H.; Teyssier, C. P.

2017-12-01

Experimental and geological-petrological studies suggest that the transition from brittle faulting to ductile flow of olivine, i.e. from seismic to aseismic behavior of mantle rocks (peridotites), occurs close to 600°C. However, recent seismological studies on oceanic transform faults (TFs) and ridges have documented earthquakes to temperatures (T) up to 700-800°C. In this study, we carried out a petrological, microstructural and geochemical analysis of natural samples of peridotites dredged at 3 different oceanic TFs of the Southwest Indian Ridge: Shaka, Prince Edward and Atlantis II. We selected samples displaying variable amounts of ductile deformation (from porphyroclastic tectonites to ultramylonites) prior to serpentinization in order to characterize their relatively high-T mechanical behavior. We find that the most deformed samples record cycles of ductile and brittle deformation. Peridotite ductile flow is characterized by drastic grain size reduction and the development of (ultra)mylonitic shear zones. In these zones, a switch in olivine deformation mechanism from dislocation creep to grain-size sensitive creep is associated with dissolution/precipitation processes. Brittle deformation of these samples is evidenced by the presence of (at least centimetric) transgranular and intragranular fractures that fragment coarser grained minerals. Both kinds of fractures are filled with the same phase assemblage as in the ultramylonitic bands: olivine + amphibole ± orthopyroxene ± Al-phase (plagioclase and/or spinel) ± sulfides. The presence of amphibole indicates that this semi-brittle deformation was assisted by hydrous fluids and its composition (e.g. high concentration of chlorine) suggests that the fluids have most likely a hydrothermal origin. We interpret these fractures to have formed under fluid-assisted conditions, recording paleo-seismic activity that alternated with periods of relatively slow interseismic ductile flow. The presence of Mg

Onondaga Lake Inner Harbor Dredging Design Project, Syracuse, New York: Finding of No Significant Impact and Environmental Assessment

DTIC Science & Technology

1996-11-01

and has determined a finding of no significant impact (FONSI). The selected Syracuse Inner Harbor dredging plan would allow the New York State Canal...Facility (CDF) UDS 5-19. The proposed plan calls for a 60 foot bottom wide channel, 10 feet deep, 3H (height): 1 (vertical) side slopes, with only the...sediments in an urban environment. The selected Syracuse Inner Harbor dredging plan would allow the New York State Canal Corporation to dredge the

Wave Glider Monitoring of Sediment Transport and Dredge Plumes in a Shallow Marine Sandbank Environment.

PubMed

Van Lancker, Vera; Baeye, Matthias

2015-01-01

As human pressure on the marine environment increases, safeguarding healthy and productive seas increasingly necessitates integrated, time- and cost-effective environmental monitoring. Employment of a Wave Glider proved very useful for the study of sediment transport in a shallow sandbank area in the Belgian part of the North Sea. During 22 days, data on surface and water-column currents and turbidity were recorded along 39 loops around an aggregate-extraction site. Correlation with wave and tidal-amplitude data allowed the quantification of current- and wave-induced advection and resuspension, important background information to assess dredging impacts. Important anomalies in suspended particulate matter concentrations in the water column suggested dredging-induced overflow of sediments in the near field (i.e., dynamic plume), and settling of finer-grained material in the far field (i.e., passive plume). Capturing the latter is a successful outcome to this experiment, since the location of dispersion and settling of a passive plume is highly dependent on the ruling hydro-meteorological conditions and thus difficult to predict. Deposition of the observed sediment plumes may cause habitat changes in the long-term.

Wave Glider Monitoring of Sediment Transport and Dredge Plumes in a Shallow Marine Sandbank Environment

PubMed Central

Van Lancker, Vera; Baeye, Matthias

2015-01-01

As human pressure on the marine environment increases, safeguarding healthy and productive seas increasingly necessitates integrated, time- and cost-effective environmental monitoring. Employment of a Wave Glider proved very useful for the study of sediment transport in a shallow sandbank area in the Belgian part of the North Sea. During 22 days, data on surface and water-column currents and turbidity were recorded along 39 loops around an aggregate-extraction site. Correlation with wave and tidal-amplitude data allowed the quantification of current- and wave-induced advection and resuspension, important background information to assess dredging impacts. Important anomalies in suspended particulate matter concentrations in the water column suggested dredging-induced overflow of sediments in the near field (i.e., dynamic plume), and settling of finer-grained material in the far field (i.e., passive plume). Capturing the latter is a successful outcome to this experiment, since the location of dispersion and settling of a passive plume is highly dependent on the ruling hydro-meteorological conditions and thus difficult to predict. Deposition of the observed sediment plumes may cause habitat changes in the long-term. PMID:26070156

Current Plate Motion Across the Southwest Indian Ridge: Implications for the Diffuse Oceanic Plate Boundary Between Nubia and Somalia

NASA Astrophysics Data System (ADS)

Horner-Johnson, B. C.; Cowles, S. M.; Gordon, R. G.; Argus, D. F.

2001-12-01

Prior studies of plate motion data along the Southwest Indian Ridge (SWIR) have produced results that conflict in detail. Chu & Gordon [1999], from an analysis of 59 spreading rates averaged over 3 Myr and of the azimuths of active transform faults, found that the data are most consistent with a diffuse Nubia-Somalia plate boundary where it intersects the SWIR. When they solve for the best-fitting hypothetical narrow boundary, they find that it lies near 37° E, east of the Prince Edward fracture zone. They find a Nubia-Somalia pole of rotation near the east coast of South Africa. In contrast, Lemaux, Gordon, and Royer [2001], from an analysis of 237 crossings of marine magnetic anomaly 5 (11 Ma), find that most of the motion is accommodated in a narrow zone, most likely along the ``inactive'' trace of the Andrew Bain fracture zone complex (ABFZC), which intersects the SWIR near 32° E. They find a pole well to the west of, and probably to the southwest of, the pole of rotation found by Chu & Gordon. Their pole indicates mainly strike-slip motion along the ``inactive'' ABFZC. To resolve these conflicting results, we determined a new greatly expanded and spatially much denser set of 243 spreading rates and analyzed available bathymetric data of active transform faults along the SWIR. The data show that the African oceanic lithosphere spreading away from the SWIR cannot simply be two plates divided by a single narrow boundary. Our interpretation of the data is as follows. Near the SWIR, there is a diffuse boundary with a western limit near the ABFZC and an eastern limit near 63.5° E. Slip is partitioned in this wide boundary. Somewhere near the ABFZC (most likely the ABFZC itself) is a concentrated locus of right-lateral shearing parallel to the ABFZC whereas contraction perpendicular to the ABFZC is accommodated east of the ABFZC, perhaps over a very broad zone.

The Impact of Fe-Ti Oxide Concentration on the Structural Rigidity of the Lower Oceanic Crust, Atlantis Bank, Southwest Indian Ridge

NASA Astrophysics Data System (ADS)

Deans, J. R.; Winkler, D. A.

2017-12-01

Fe-Ti oxides are important components of oceanic core complexes (OCC) formed at slow-spreading ridges, since Fe-Ti oxide phases form throughout the crustal column and are weaker than silicate phases. This study investigated the predicted relationship between the presence and concentration of Fe-Ti oxides and the presence/intensity of crystal-plastic deformation in samples from Atlantis Bank, Southwest Indian Ridge (SWIR). Atlantis Bank is an OCC that formed through the exhumation of lower oceanic crust along a detachment shear zone/fault. OCCs form along slow-spreading ridges and are characterized by the complex interactions between magmatism and crustal extension, thus, making them more susceptible to crystal-plastic deformation at higher temperatures and for weaker phases like Fe-Ti oxides to preferentially partition strain. Atlantis Bank has been the focus of many scientific expeditions to various sites including; Ocean Drilling Program (ODP) Holes 735B and 1105A, and the International Oceanic Discovery Program (IODP) Hole U1473A. A total of 589 thin sections from all three holes were analyzed using the software package Fiji to calculate the Fe-Ti oxide concentration within the thin sections. The Fe-Ti oxide percentage was correlated with the crystal-plastic fabric (CPF) intensity, from 0-5 (no foliation - ultramylonite), for each thin section using the statistical software R. All three holes show a positive correlation between the abundance of Fe-Ti oxides and the CPF intensity. Specifically, 76.3% of samples with a concentration of 5% or more Fe-Ti oxides have a corresponding CPF intensity value of 2 or more (porphyroclastic foliation - ultramylonitic). The positive correlation may be explained by the Fe-Ti oxides preferentially partitioning strain, especially at temperatures below where dry plagioclase can recrystallize. This allows for a mechanism of continued slip along the shear zone or form new shear zones at amphibolite grade conditions while the lower

Studies in Southwest Spanish.

ERIC Educational Resources Information Center

Bowen, J. Donald, Ed.; Ornstein, Jacob, Ed.

The Spanish dialects of the Southwest United States have received little serious attention until recently. The present volume contains studies designed to contribute to the understanding and acceptance of Southwest Spanish. The book consists of the following chapters: (1) "Linguistic Diversity in Southwest Spanish," by Garland D. Bills…

Theoretical Models for Evaluation of Volatile Emissions to Air During Dredged Material Disposal with Applications to New Bedford Harbor, Massachusetts

DTIC Science & Technology

1989-05-01

model otherwise. 7. One or more partial differential equations can be presented to describe the minutia of chemical behavior in the various locales of...enjoys a voluminous literature heritage beyond the point of realistic applications to the natural environment in many cases. Hill, Myers, and Brannon...represented by the point A in Figure 2. This point may be representative of the recently deposited and exposed surface of dredged sediment in the delta

Lipid geochemistry of remote aerosols from the southwestern Pacific Ocean sector

NASA Astrophysics Data System (ADS)

Sicre, Marie-Alexandrine; Peltzer, Edward T.

Aerosol samples collected on Ninety Mile Beach on the West coast of the North Island of New Zealand were analyzed for three classes of naturally occurring organic compounds ( n-alkanes, fatty alcohols and long-chain n-aldehydes) which are major constituents of epicuticular waxes of terrestrial plants. In the eight samples analyzed, we identified three distinct regional source signatures for these aerosols depending upon their origin: southwest Pacific Ocean, New Zealand or Australia. Source identifications were entirely consistent with the origin of the aerosols derived by isentropic air mass trajectories. Impactor studies provided additional information as to the source of the aerosols and the mode of introduction of the material into the atmosphere.

Hawaiian submarine manganese-iron oxide crusts - A dating tool?

USGS Publications Warehouse

Moore, J.G.; Clague, D.A.

2004-01-01

Black manganese-iron oxide crusts form on most exposed rock on the ocean floor. Such crusts are well developed on the steep lava slopes of the Hawaiian Ridge and have been sampled during dredging and submersible dives. The crusts also occur on fragments detached from bedrock by mass wasting, on submerged coral reefs, and on poorly lithified sedimentary rocks. The thickness of the crusts was measured on samples collected since 1965 on the Hawaiian Ridge from 140 dive or dredge localities. Fifty-nine (42%) of the sites were collected in 2001 by remotely operated vehicles (ROVs). The thinner crusts on many samples apparently result from post-depositional breakage, landsliding, and intermittent burial of outcrops by sediment. The maximum crust thickness was selected from each dredge or dive site to best represent crusts on the original rock surface at that site. The measurements show an irregular progressive thickening of the crusts toward the northwest-i.e., progressive thickening toward the older volcanic features with increasing distance from the Hawaiian hotspot. Comparison of the maximum crust thickness with radiometric ages of related subaerial features supports previous studies that indicate a crust-growth rate of about 2.5 mm/m.y. The thickness information not only allows a comparison of the relative exposure ages of two or more features offshore from different volcanoes, but also provides specific age estimates of volcanic and landslide deposits. The data indicate that some of the landslide blocks within the south Kona landslide are the oldest exposed rock on Mauna Loa, Kilauea, or Loihi volcanoes. Crusts on the floors of submarine canyons off Kohala and East Molokai volcanoes indicate that these canyons are no longer serving as channelways for downslope, sediment-laden currents. Mahukona volcano was approximately synchronous with Hilo Ridge, both being younger than Hana Ridge. The Nuuanu landslide is considerably older than the Wailau landslide. The Waianae

Effects of dredging operations on soft bottom macrofauna in a harbor in the Patos Lagoon estuarine region of southern Brazil.

PubMed

Bemvenuti, C E; Angonesi, L G; Gandra, M S

2005-11-01

An evaluation was made of the effects of dredging on the soft bottom community in the channel of the Rio Grande harbor in the Patos Lagoon estuarine region of southern Brazil. During four seasonal cruises, samples were collected from nine biological stations, one of which was located outside the dredged area. Three macrobenthic samples were collected on each cruise from each station, using a 0.08 m2 van Veen grab. A cluster analysis was applied to group summer and autumn cruise stations before the dredging period, revealing larger numbers of species (35-36 spp.) and higher densities of organisms. The station located outside the dredging area was always included in this group, regardless of the sampling period or conditions of salinity. Another group comprised the winter and spring stations during the dredging period. This group was characterized by stations with the fewest species (20-18 spp.) and the lowest and most variable organism densities. The efficient strategies of resilience of the dominant estuarine species may minimize the effects of dredging on the biota through the rapid recolonization of the soft bottom of the harbor channel.

78 FR 11094 - Safety Zone; Lake Worth Dredge Operations, Lake Worth Inlet; West Palm Beach, FL

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-15

... 1625-AA00 Safety Zone; Lake Worth Dredge Operations, Lake Worth Inlet; West Palm Beach, FL AGENCY... safety zone on Lake Worth Inlet, West Palm Beach, Florida, to provide for the safety of life and vessels..., dredging operations will be conducted on Lake Worth Inlet in West Palm Beach, Florida. These operations...

A new genus and species of deep-sea glass sponge (Porifera, Hexactinellida, Aulocalycidae) from the Indian Ocean.

PubMed

Sautya, Sabyasachi; Tabachnick, Konstantin R; Ingole, Baban

2011-01-01

New hexactinellid sponges were collected from 2589 m depth on the Carlsberg Ridge in the Indian Ocean during deep-sea dredging. All fragments belong to a new genus and species, Indiellagen. n.ridgenensissp. n., a representative of the family Aulocalycidae described here. The peculiar features of this sponge, not described earlier for other Aulocalycidae, are: longitudinal strands present in several layers and epirhyses channelization.

Development of a dredge planning and decision support tool.

DOT National Transportation Integrated Search

2004-12-01

The report presented herein is a comprehensive overview of the practice of harbor dredging : at the Port of New York and New Jersey, USA. The study was commissioned by the Port : Authority of Piraeus, Greece with the objective of creating a database ...

Geoarchaeological evidence for dredging in Tyre's ancient harbour, Levant

NASA Astrophysics Data System (ADS)

Marriner, Nick; Morhange, Christophe

2006-01-01

Chrono-stratigraphic data from Tyre's ancient northern harbour delineate extensive dredging practices during the Greco-Roman and Byzantine periods. Radiocarbon dates from four cores consistently cluster between ca. 500 B.C. and 1000 A.D. and indicate rapid rates of sedimentation in the basin, namely ∼10 mm/yr during the Greco-Roman and Byzantine periods, compared to 0.5-1 mm/yr for the period 6000-4000 B.C. Absence of strata between 4000 B.C. and 500 B.C. is not consistent with a natural base-level sediment sink and cannot be interpreted as a depositional hiatus in the high-stand systems tract. Ancient dredging is further corroborated by persistent age-depth inversions within the fine-grained harbour facies. These data support removal of Middle Bronze Age to Persian period sediment strata, with deliberate overdeepening of the harbour bottom by Greco-Roman and Byzantine societies.

Assessment Of Bioaccumulation Potential Following Dredging In Mainistique, Michigan

EPA Science Inventory

After the Superfund remedy of the Mainistique River and Harbor that occurred in 1996 to 2001, PCB concentrations in sediment have gone down substantially. Prior to dredging, the average PCB concentration was 28 ppm (all depth intervals) and the current average in sediments is 0....

Relocation of earthquakes at southwestern Indian Ocean Ridge and its tectonic significance

NASA Astrophysics Data System (ADS)

Luo, W.; Zhao, M.; Haridhi, H.; Lee, C. S.; Qiu, X.; Zhang, J.

2015-12-01

The southwest Indian Ridge (SWIR) is a typical ultra-slow spreading ridge (Dick et al., 2003) and further plate boundary where the earthquakes often occurred. Due to the lack of the seismic stations in SWIR, positioning of earthquakes and micro-earthquakes is not accurate. The Ocean Bottom Seismometers (OBS) seismic experiment was carried out for the first time in the SWIR 49 ° 39 'E from Jan. to March, 2010 (Zhao et al., 2013). These deployed OBS also recorded the earthquakes' waveforms during the experiment. Two earthquakes occurred respectively in Feb. 7 and Feb. 9, 2010 with the same magnitude of 4.4 mb. These two earthquakes were relocated using the software HYPOSAT based on the spectrum analysis and band-pass (3-5 Hz) filtering and picking up the travel-times of Pn and Sn. Results of hypocentral determinations show that there location error is decreased significantly by joined OBS's recording data. This study do not only provide the experiences for the next step deploying long-term wide-band OBSs, but also deepen understanding of the structure of SWIR and clarify the nature of plate tectonic motivation. This research was granted by the Natural Science Foundation of China (41176053, 91028002, 91428204). Keywords: southwest Indian Ridge (SWIR), relocation of earthquakes, Ocean Bottom Seismometers (OBS), HYPOSAT References:[1] Dick, H. J. B., Lin J., Schouten H. 2003. An ultraslow-spreading class of ocean ridge. Nature, 426(6965): 405-412. [2] Zhao M. H., et al. 2013. Three-dimensional seismic structure of the Dragon Flag oceanic core complex at the ultraslow spreading Southwest Indian Ridge (49°39' E). Geochemistry Geophysics Geosystems, 14(10): 4544-4563.

Annual cycles of deep-ocean biogeochemical export fluxes in subtropical and subantarctic waters, southwest Pacific Ocean

NASA Astrophysics Data System (ADS)

Nodder, Scott D.; Chiswell, Stephen M.; Northcote, Lisa C.

2016-04-01

The annual cycles of particle fluxes derived from moored sediment trap data collected during 2000-2012 in subtropical (STW) and subantarctic waters (SAW) east of New Zealand are presented. These observations are the most comprehensive export flux time series from temperate Southern Hemisphere latitudes to date. With high levels of variability, fluxes in SAW were markedly lower than in STW, reflecting the picophytoplankton-dominated communities in the iron-limited, high nutrient-low chlorophyll SAW. Austral spring chlorophyll blooms in surface STW were near synchronous with elevated fluxes of bio-siliceous, carbonate, and organic carbon-rich materials to the deep ocean, probably facilitated by diatom and/or coccolithophorid sedimentation. Lithogenic fluxes were also high in STW, compared to SAW, reflecting proximity to the New Zealand landmass. In contrast, the highest biogenic fluxes in SAW occurred in spring when surface chlorophyll concentrations were low, while highest annual chlorophyll concentrations were in summer with no associated flux increase. We hypothesize that the high spring export in SAW results from subsurface chlorophyll accumulation that is not evident from remote-sensing satellites. This material was also rich in biogenic silica, perhaps related to the preferential export of diatoms and other silica-producing organisms, such as silicoflagellates and radiolarians. Organic carbon fluxes in STW are similar to that of other mesotrophic to oligotrophic waters (˜6-7 mg C m-2 d-1), whereas export from SAW is below the global average (˜3 mg C m-2 d-1). Regional differences in flux across the SW Pacific and Tasman region reflect variations in physical processes and ecosystem structure and function.

Increased fluxes of shelf-derived materials to the central Arctic Ocean

PubMed Central

Kipp, Lauren E.; Charette, Matthew A.; Moore, Willard S.; Henderson, Paul B.; Rigor, Ignatius G.

2018-01-01

Rising temperatures in the Arctic Ocean region are responsible for changes such as reduced ice cover, permafrost thawing, and increased river discharge, which, together, alter nutrient and carbon cycles over the vast Arctic continental shelf. We show that the concentration of radium-228, sourced to seawater through sediment-water exchange processes, has increased substantially in surface waters of the central Arctic Ocean over the past decade. A mass balance model for 228Ra suggests that this increase is due to an intensification of shelf-derived material inputs to the central basin, a source that would also carry elevated concentrations of dissolved organic carbon and nutrients. Therefore, we suggest that significant changes in the nutrient, carbon, and trace metal balances of the Arctic Ocean are underway, with the potential to affect biological productivity and species assemblages in Arctic surface waters. PMID:29326980

The impact of disposal of fine-grained sediments from maintenance dredging works on SPM concentration and fluid mud in and outside the harbor of Zeebrugge

NASA Astrophysics Data System (ADS)

Fettweis, Michael; Baeye, Matthias; Cardoso, Claudio; Dujardin, Arvid; Lauwaert, Brigitte; Van den Eynde, Dries; Van Hoestenberghe, Thomas; Vanlede, Joris; Van Poucke, Luc; Velez, Carlos; Martens, Chantal

2016-11-01

The amount of sediments to be dredged and disposed depends to a large part on the suspended particulate matter (SPM) concentration. Tidal, meteorological, climatological, and seasonal forcings have an influence on the horizontal and vertical distribution of the SPM in the water column and on the bed and control the inflow of fine-grained sediments towards harbors and navigation channels. About 3 million tons (dry matter) per year of mainly fine-grained sediments is dredged in the port of Zeebrugge and is disposed on a nearby disposal site. The disposed sediments are quickly resuspended and transported away from the site. The hypothesis is that a significant part of the disposed sediments recirculates back to the dredging places and that a relocation of the disposal site to another location at equal distance to the dredging area would reduce this recirculation. In order to validate the hypothesis, a 1-year field study was set up in 2013-2014. During 1 month, the dredged material was disposed at a new site. Variations in SPM concentration were related to tides, storms, seasonal changes, and human impacts. In the high-turbidity Belgian near-shore area, the natural forcings are responsible for the major variability in the SPM concentration signal, while disposal has only a smaller influence. The conclusion from the measurements is that the SPM concentration decreases after relocation of the disposal site but indicate stronger (first half of field experiment) or weaker (second half of field experiment) effects that are, however, supported by the environmental conditions. The results of the field study may have consequences on the management of disposal operations as the effectiveness of the disposal site depends on environmental conditions, which are inherently associated with chaotic behavior.

Petrogenesis of fertile mantle peridotites from the Monte del Estado massif (southwest Puerto Rico): a preserved section of Proto-Caribbean oceanic lithospheric mantle?

NASA Astrophysics Data System (ADS)

Marchesi, Claudio; Jolly, Wayne T.; Lewis, John F.; Garrido, Carlos J.; Proenza, Joaquín. A.; Lidiak, Edward G.

2010-05-01

The Monte del Estado massif is the largest and northernmost serpentinized peridotite belt in southwest Puerto Rico. It is mainly composed of spinel lherzolite and minor harzburgite with variable clinopyroxene modal abundances. Mineral and whole rock major and trace element compositions of peridotites coincide with those of fertile abyssal peridotites from mid ocean ridges. Peridotites lost 2-14 wt% of relative MgO and variable amounts of CaO by serpentinization and seafloor weathering. HREE contents in whole rock indicate that the Monte del Estado peridotites are residues after low to moderate degrees (2-15%) of fractional partial melting in the spinel stability field. However, very low LREE/HREE and MREE/HREE in clinopyroxene cannot be explained by melting models of a spinel lherzolite source and support that the Monte del Estado peridotites experienced initial low fractional melting degrees (~ 4%) in the garnet stability field. The relative enrichment of LREE in whole rock is not due to secondary processes but probably reflects the capture of percolating melt fractions along grain boundaries or as microinclusions in minerals, or the presence of exotic micro-phases in the mineral assemblage. We propose that the Monte del Estado peridotite belt represents a section of ancient Proto-Caribbean (Atlantic) lithospheric mantle originated by seafloor spreading between North and South America in the Late Jurassic-Early Cretaceous. This portion of oceanic lithospheric mantle was subsequently trapped in the forearc region of the Greater Antilles paleo-island arc generated by the northward subduction of the Caribbean plate beneath the Proto-Caribbean ocean. Finally, the Monte del Estado peridotites belt was emplaced in the Early Cretaceous probably as result of the change in subduction polarity of the Greater Antilles paleo-island arc without having been significantly modified by subduction processes.

Mid Ocean Ridge Processes at Very Low Melt Supply : Submersible Exploration of Smooth Ultramafic Seafloor at the Southwest Indian Ridge, 64 degree E

NASA Astrophysics Data System (ADS)

Cannat, M.; Agrinier, P.; Bickert, M.; Brunelli, D.; Hamelin, C.; Lecoeuvre, A.; Lie Onstad, S.; Maia, M.; Prampolini, M.; Rouméjon, S.; Vitale Brovarone, A.; Besançon, S.; Assaoui, E. M.

2017-12-01

Mid-ocean ridges are the Earth's most extensive and active volcanic chains. They are also, particularly at slow spreading rates, rift zones, where plate divergence is in part accommodated by faults. Large offset normal faults, also called detachments, are characteristic of slow-spreading ridges, where they account for the widespread emplacement of mantle-derived rocks at the seafloor. In most cases, these detachments occur together with ridge magmatism, with melt injection and faulting interacting to shape the newly formed oceanic lithosphere. Here, we seek to better understand these interactions and their effects on oceanic accretion by studying the end-member case of a ridge where magmatism is locally almost absent. The portion of the Southwest Indian ridge we are studying has an overal low melt supply, focused to discrete axial volcanoes, leaving almost zero melt to intervening sections of the axial valley. One of these nearly amagmatic section of the ridge, located at 64°E, has been the focus of several past cruises (sampling, mapping and seismic experiments). Here we report on the most recent cruise to the area (RV Pourquoi Pas? with ROV Victor; dec-jan 2017), during which we performed high resolution mapping, submersible exploration and sampling of the ultramafic seafloor and of sparse volcanic formations. Our findings are consistent with the flip-flop detachment hypothesis proposed for this area by Sauter et al. (Nature Geosciences, 2013; ultramafic seafloor forming in the footwall of successive detachment faults, each cutting into the footwall of the previous fault, with an opposite polarity). Our observations also document the extent and geometry of deformation in the footwall of a young axial detachment, the role of mass-wasting for the evolution of this detachment, and provide spectacular evidence for serpentinization-related hydrothermal circulation and for spatial links between faults and volcanic eruptions.

Interannual variability of Indian Ocean subtropical mode water subduction rate

NASA Astrophysics Data System (ADS)

Ma, Jie; Lan, Jian

2017-06-01

The interannual variation of Indian Ocean subtropical mode water (IOSTMW) subduction rate in the Southwest Indian Ocean from 1980 to 2007 is investigated in this paper based on Simple Ocean Data Assimilation (SODA) outputs. Climatology of subduction rate exceeds 75 m/year in the IOSTMW formation area. The renewal time of permanent pycnocline water mass based on the subduction rate is calculated for each density class: 3-6 years for IOSTMW (25.8 < σ θ < 26.2 kg m-3). Subduction rate in the Southwest Indian Ocean subtropical gyre exhibits a great year-to-year variability. This interannual variations of the IOSTMW subduction rate is primarily dominated by the lateral induction term, associated with the interannual variations of strong meridional gradient of winter mixed layer depth (MLD). The slope of the mixed layer depth in the mode water is closely linked to the large variations of deep late winter MLD in the mid-latitudes and negligible variations of shallow winter MLD in lower latitudes. It is further identified that the interannual variation of late winter MLD in this area is largely controlled by the latent and sensible heat flux components. The water volume of the permanent pycnocline in the IOSTMW distribution area is also found to show a significant interannual variability, and it is well correlated with the interannual variation of subduction rate.

Synthetic Pn and Sn phases and the frequency dependence of Q of oceanic lithosphere

NASA Astrophysics Data System (ADS)

Sereno, Thomas J., Jr.; Orcutt, John A.

1987-04-01

The oceanic lithosphere is an extremely efficient waveguide for high-frequency seismic energy. In particular, the propagation of the regional to teleseismic oceanic Pn and Sn phases is largely controlled by properties of the oceanic plates. The shallow velocity gradient in the sub-Moho lithosphere results in a nearly linear travel time curve for these oceanic phases and an onset velocity near the material velocity of the uppermost mantle. The confinement of Pn/Sn to the lithosphere imposes a constraint on the maximum range that a normally refracted wave can be observed. The rapid disappearance of Sn and the discontinuous drop in Pn/Sn group velocity beyond a critical distance, dependent upon the local thickness of the lithosphere, are interpreted as a shadowing effect of the low Q asthenosphere. Wave number integration was used to compute complete synthetic seismograms for a model of oceanic lithosphere. The results were compared to data collected during the 1983 Ngendei Seismic Experiment in the southwest Pacific. The Pn/Sn coda is successfully modeled as a sum of leaky organ-pipe modes in the sediment layer and oceanic water column. While scattering is present to some degree, it is not required to explain the long duration and complicated nature of the Pn/Sn wave trains. The presence of extremely high frequencies in Pn/Sn phases and the greater efficiency of Sn than Pn propagation are interpreted in terms of an absorption band rheology. A shorter high-frequency relaxation time for P waves than for S waves results in a rheology with the property that Qα > Qβ at low frequency while Qβ > Qα at high frequency, consistent with the teleseismic Pn/Sn observations. The absorption band model is to viewed as only an approximation to the true frequency dependence of Q in the oceanic lithosphere for which analytic expressions for the material dispersion have been developed.

75 FR 19964 - Notice of Staff Attendance at Southwest Power Pool Regional State Committee Meeting and Southwest...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-16

... Power Pool, Inc. Docket No. ER10-696, Southwest Power Pool, Inc. Docket No. ER10-697, Southwest Power Pool, Inc. Docket No. ER10-698, Southwest Power Pool, Inc. Docket No. ER10-700, Southwest Power Pool...

A new genus and species of deep-sea glass sponge (Porifera, Hexactinellida, Aulocalycidae) from the Indian Ocean

PubMed Central

Sautya, Sabyasachi; Tabachnick, Konstantin R.; Ingole, Baban

2011-01-01

Abstract New hexactinellid sponges were collected from 2589 m depth on the Carlsberg Ridge in the Indian Ocean during deep-sea dredging. All fragments belong to a new genus and species, Indiella gen. n. ridgenensis sp. n., a representative of the family Aulocalycidae described here. The peculiar features of this sponge, not described earlier for other Aulocalycidae, are: longitudinal strands present in several layers and epirhyses channelization. PMID:22140345

Material Evidence for Ocean Impact from Shock-Metamorphic Experiments

NASA Astrophysics Data System (ADS)

Miura, Y.; Takayama, K.; Iancu, O. G.

1993-07-01

Continental impact reveals an excavated crater that has few fresh fine ejecta showing major high shock metamorphism due to weathering [1]. A giant ocean impact rarely remains as an excavated crater mainly due to crushing by dynamic plate-tectonic movements on the crust [2]. However, all impact materials, including fine-grained ejecta, can be obtained with artificial impact experiments [3]. The purpose of this study is to discuss material evidence for ocean impact based on shock-metamorphic experiments. Artificial impact experiments indicate that fine shocked quartz (SQ) aggregates can be formed on several target rocks (Table 1) [1]. It is found in Table 1 that (1) the largest-density deviation of SQ grain is found not at the wall-rock or the impact crater but at fine-grained ejecta, and (2) silica-poor rocks of basalt, gabbro, and anorthosite can also make fine SQ aggregates by impact. Table 1, which appears here in the hard copy, shows formations of fine shocked quartz aggregates from ocean-floor rocks of basalt, gabbroic anorthosite, and granite [3]. An asteroid (about 10 km across) hits the Earth ~65 m.y. ago [4] to result in global catastrophe by titanic explosion and climate change. But shocked quartz grains found in the K/T boundary layer were considered to come from crystalline continental rocks [5]. The present result as listed in Table 1 indicates that fine SQ aggregates can also be formed at sea-floor basaltic and gabbroic rocks [3]. The present result of formation of the SQ grains from sea- floor target rocks is nearly consistent with the finding of a sea-impact crater at the K/T boundary near the Caribbean [6]. Impact-induced volcanism at the K/T boundary can explained by the penetration from thin ocean crust to upper mantle reservoirs, if giant impact of a 10-km- diameter asteroid hit the ocean [2,7]. The present result can explain "phreatomagmatic (magmatic vapor) explosion," which is created by abrupt boiling between high-temperature magma and cold

An innovative coupling between column leaching and oxygen consumption tests to assess behavior of contaminated marine dredged sediments.

PubMed

Couvidat, Julien; Benzaazoua, Mostafa; Chatain, Vincent; Zhang, Fan; Bouzahzah, Hassan

2015-07-01

Contaminated dredged sediments are often considered hazardous wastes, so they have to be adequately managed to avoid leaching of pollutants. The mobility of inorganic contaminants is a major concern. Metal sulfides (mainly framboïdal pyrite, copper, and zinc sulfides) have been investigated in this study as an important reactive metal-bearing phase sensitive to atmospheric oxygen action. An oxygen consumption test (OC-Test) has been adapted to assess the reactivity of dredged sediments when exposed to atmospheric oxygen. An experimental column set-up has been developed allowing the coupling between leaching and oxygen consumption test to investigate the reactivity of the sediment. This reactivity, which consisted of sulfide oxidation, was found to occur for saturation degree between 60 and 90 % and until the 20th testing week, through significant sulfates releases. These latter were assumed to come from sulfide oxidation in the first step of the test, then probably from gypsum dissolution. Confrontation results of OC-Test and leachate quality shows that Cu was well correlated to sulfates releases, which in turn, leads to Ca and Mg dissolution (buffer effect). Cu, and mostly Zn, was associated to organic matter, phyllosilicates, and other minerals through organo-clay complexes. This research confirmed that the OC-Test, originally developed for mine tailings, could be a useful tool in the dredged sediment field which can allow for intrinsic characterization of reactivity of a material suspected to readily reacting with oxygen and for better understanding of geochemical processes that affect pollutants behavior, conversion, and transfer in the environment.

Marine debris ingestion by albatrosses in the southwest Atlantic Ocean.

PubMed

Jiménez, Sebastián; Domingo, Andrés; Brazeiro, Alejandro; Defeo, Omar; Phillips, Richard A

2015-07-15

Plastics and other marine debris affect wildlife through entanglement and by ingestion. We assessed the ingestion of marine debris by seven albatross species in the southwest Atlantic by analyzing stomach contents of birds killed in fisheries. Of the 128 specimens examined, including four Diomedea species (n=78) and three Thalassarche species (n=50), 21 (16.4%) contained 1-4 debris items, mainly in the ventriculus. The most common type was plastic fragments. Debris was most frequent in Diomedea species (25.6%) and, particularly, Diomedea sanfordi (38.9%) and very rare in Thalassarche species (2.0%), presumably reflecting differences in foraging behavior or distribution. Frequency of occurrence was significantly higher in male than female Diomedea albatrosses (39.3% vs. 18.0%). Although levels of accumulated debris were relatively low overall, and unlikely to result in gut blockage, associated toxins might nevertheless represent a health risk for Diomedea albatrosses, compounding the negative impact of other human activities on these threatened species. Copyright © 2015 Elsevier Ltd. All rights reserved.

La Niña diversity and Northwest Indian Ocean Rim teleconnections

USGS Publications Warehouse

Hoell, Andrew; Funk, Christopher C.; Barlow, Mathew

2014-01-01

The differences in tropical Pacific sea surface temperature (SST) expressions of El Niño-Southern Oscillation (ENSO) events of the same phase have been linked with different global atmospheric circulation patterns. This study examines the dynamical forcing of precipitation during October–December (OND) and March–May (MAM) over East Africa and during December–March (DJFM) over Central-Southwest Asia for 1950–2010 associated with four tropical Pacific SST patterns characteristic of La Niña events, the cold phase of ENSO. The self-organizing map method along with a statistical distinguishability test was used to isolate La Niña events, and seasonal precipitation forcing was investigated in terms of the tropical overturning circulation and thermodynamic and moisture budgets. Recent La Niña events with strong opposing SST anomalies between the central and western Pacific Ocean (phases 3 and 4), force the strongest global circulation modifications and drought over the Northwest Indian Ocean Rim. Over East Africa during MAM and OND, subsidence is forced by an enhanced tropical overturning circulation and precipitation reductions are exacerbated by increases in moisture flux divergence. Over Central-Southwest Asia during DJFM, the thermodynamic forcing of subsidence is primarily responsible for precipitation reductions, with moisture flux divergence acting as a secondary mechanism to reduce precipitation. Eastern Pacific La Niña events in the absence of west Pacific SST anomalies (phases 1 and 2), are associated with weaker global teleconnections, particularly over the Indian Ocean Rim. The weak regional teleconnections result in statistically insignificant precipitation modifications over East Africa and Central-Southwest Asia.

Tidal-flow, circulation, and flushing changes caused by dredge and fill in Hillsborough Bay, Florida

USGS Publications Warehouse

Goodwin, Carl R.

1991-01-01

Hillsborough Bay, Florida, underwent extensive physical changes between 1880 and 1972 because of the construction of islands, channels, and shoreline fills. These changes resulted in a progressive reduction in the quantity of tidal water that enters and leaves the bay. Dredging and filling also changed the magnitude and direction of tidal flow in most of the bay. A two-dimensional, finite-difference hydrodynamic model was used to simulate flood, ebb, and residual water transport for physical conditions in Hillsborough Bay and the northeastern part of Middle Tampa Bay during 1880, 1972, and 1985. The calibrated and verified model was used to evaluate cumulative water-transport changes resulting from construction in the study area between 1880 and 1972. The model also was used to evaluate water-transport changes as a result of a major Federal dredging project completed in 1985. The model indicates that transport changes resulting from the Federal dredging project are much less areally extensive than the corresponding transport changes resulting from construction between 1880 and 1972. Dredging-caused changes of more than 50 percent in flood and ebb water transport were computed to occur over only about 8 square miles of the 65-square-mile study area between 1972 and 1985. Model results indicate that construction between 1880 and 1972 caused changes of similar magnitude over about 23 square miles. Dredging-caused changes of more than 50 percent in residual water transport were computed to occur over only 17 square miles between 1972 and 1985. Between 1880 and 1972, changes of similar magnitude were computed to occur over an area of 45 square miles. Model results also reveal historical tide-induced circulation patterns. The patterns consist of a series of about 8 interconnected circulatory features in 1880 and as many as 15 in 1985. Dredging- and construction-caused changes in number, size, position, shape, and intensity of the circulatory features increase tide

Dredging for dilution: A simulation based case study in a Tidal River.

PubMed

Bilgili, Ata; Proehl, Jeffrey A; Swift, M Robinson

2016-02-01

A 2-D hydrodynamic finite element model with a Lagrangian particle module is used to investigate the effects of dredging on the hydrodynamics and the horizontal dilution of pollutant particles originating from a wastewater treatment facility (WWTF) in tidal Oyster River in New Hampshire, USA. The model is driven by the semi-diurnal (M2) tidal component and includes the effect of flooding and drying of riverine mud flats. The particle tracking method consists of tidal advection plus a horizontal random walk model of sub-grid scale turbulent processes. Our approach is to perform continuous pollutant particle releases from the outfall, simulating three different scenarios: a base-case representing the present conditions and two different dredged channel/outfall location configurations. Hydrodynamics are investigated in an Eulerian framework and Lagrangian particle dilution improvement ratios are calculated for all cases. Results show that the simulated hydrodynamics are consistent with observed conditions. Eulerian and Lagrangian residuals predict an outward path suggesting flushing of pollutants on longer (>M2) time scales. Simulated dilution maps show that, in addition to dredging, the relocation of the WWTF outfall into the dredged main channel is required for increased dilution performance. The methodology presented here can be applied to similar managerial problems in all similar systems worldwide with relatively little effort, with the combination of Lagrangian and Eulerian methods working together towards a better solution. The statistical significance brought into methodology, by using a large number of particles (16000 in this case), is to be emphasized, especially with the growing number of networked parallel computer clusters worldwide. This paper improves on the study presented in Bilgili et al., 2006b, by adding an Eulerian analysis. Copyright © 2015 Elsevier Ltd. All rights reserved.

Evaluation of Global Ocean Data Assimilation Experiment Products on South Florida Nested Simulations with the Hybrid Coordinate Ocean Model

DTIC Science & Technology

2009-01-01

Ocean Model 7:285-322 Halliwell GR Jr, Weisberg RH, Mayer DA (2003) A synthetic float analysis of upper-limb meridional overturning circulation ...encompasses a variety of coastal regions (the broad Southwest Florida shelf, the narrow Atlantic Keys shelf, the shallow Florida Bay, and Biscayne...products. The results indicate that the successful hindcasting of circulation patterns in a coastal area that is characterized by complex topography and

Widespread Neogene and Quaternary Volcanism on Central Kerguelen Plateau, Southern Indian Ocean

NASA Astrophysics Data System (ADS)

Duncan, R. A.; Falloon, T.; Quilty, P. G.; Coffin, M. F.

2016-12-01

We report new age determinations and compositions for rocks from 18 dredge hauls collected from eight submarine areas across Central Kerguelen Plateau (CKP). Sea knolls and volcanic fields with multiple small cones were targeted over a 125,000 km2 region that includes Heard and McDonald islands. Large early Miocene (16-22 Ma) sea knolls rise from the western margin of the CKP and are part of a NNW-SSE line of volcanic centers that lie between Îles Kerguelen and Heard and McDonald islands. A second group of large sea knolls is aligned E-W across the center of this region. We see evidence of much younger activity (5 Ma to present) in volcanic fields to the north of, and up to 300 km NE of Heard Island. Compositions include basanite, basalt, and trachybasalt, that are broadly similar to plateau lava flows from nearby Ocean Drilling Program (ODP) Site 1138, lower Miocene lavas at Îles Kerguelen, dredged rocks from the early Miocene sea knolls, and Big Ben lavas from Heard Island. Geochemical data indicate decreasing fractions of mantle source melting with time. The western line of sea knolls has been related to hotspot activity now underlying the Heard Island area. In view of the now recognized much larger area of young volcanic activity, we propose that a broad region of CKP became volcanically active in Neogene time due to incubation of plume material at the base of the relatively stationary overlying plateau. The presence of pre-existing crustal faults promotes access for melts from the Heard mantle plume to rise to the surface.

California Least Tern Foraging Ecology in Southern California: A Review of Foraging Behavior Relative to Proposed Dredging Locations

DTIC Science & Technology

2016-05-01

Communication. B. Hoffman. ERDC/EL CR-16-3 19 locations, including areas where active dredging was occurring. Secchi disc readings ranged from 0.5 to 1.3...low numbers of CLT dives were also recorded during other days of dredge disposal when turbidity readings , via Secchi disc, were similar to readings

East yard, looking southwest at car repairer's locker house (left), ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

East yard, looking southwest at car repairer's locker house (left), switchment shanty (center), and material storage rack (right). - Chesapeake & Ohio Railroad, Thurmond Yards, East side New River, mouths of Arbuckle & Dunlop Circles, Thurmond, Fayette County, WV

Effects of light attenuation on the sponge holobiont- implications for dredging management

PubMed Central

Pineda, Mari-Carmen; Strehlow, Brian; Duckworth, Alan; Doyle, Jason; Jones, Ross; Webster, Nicole S.

2016-01-01

Dredging and natural sediment resuspension events can cause high levels of turbidity, reducing the amount of light available for photosynthetic benthic biota. To determine how marine sponges respond to light attenuation, five species were experimentally exposed to a range of light treatments. Tolerance thresholds and capacity for recovery varied markedly amongst species. Whilst light attenuation had no effect on the heterotrophic species Stylissa flabelliformis and Ianthella basta, the phototrophic species Cliona orientalis and Carteriospongia foliascens discoloured (bleached) over a 28 day exposure period to very low light (<0.8 mol photons m−2 d−1). In darkness, both species discoloured within a few days, concomitant with reduced fluorescence yields, chlorophyll concentrations and shifts in their associated microbiomes. The phototrophic species Cymbastela coralliophila was less impacted by light reduction. C. orientalis and C. coralliophila exhibited full recovery under normal light conditions, whilst C. foliascens did not recover and showed high levels of mortality. The light treatments used in the study are directly relevant to conditions that can occur in situ during dredging projects, indicating that light attenuation poses a risk to photosynthetic marine sponges. Examining benthic light levels over temporal scales would enable dredging proponents to be aware of conditions that could impact on sponge physiology. PMID:27958345

Effects of light attenuation on the sponge holobiont- implications for dredging management.

PubMed

Pineda, Mari-Carmen; Strehlow, Brian; Duckworth, Alan; Doyle, Jason; Jones, Ross; Webster, Nicole S

2016-12-13

Dredging and natural sediment resuspension events can cause high levels of turbidity, reducing the amount of light available for photosynthetic benthic biota. To determine how marine sponges respond to light attenuation, five species were experimentally exposed to a range of light treatments. Tolerance thresholds and capacity for recovery varied markedly amongst species. Whilst light attenuation had no effect on the heterotrophic species Stylissa flabelliformis and Ianthella basta, the phototrophic species Cliona orientalis and Carteriospongia foliascens discoloured (bleached) over a 28 day exposure period to very low light (<0.8 mol photons m -2 d -1 ). In darkness, both species discoloured within a few days, concomitant with reduced fluorescence yields, chlorophyll concentrations and shifts in their associated microbiomes. The phototrophic species Cymbastela coralliophila was less impacted by light reduction. C. orientalis and C. coralliophila exhibited full recovery under normal light conditions, whilst C. foliascens did not recover and showed high levels of mortality. The light treatments used in the study are directly relevant to conditions that can occur in situ during dredging projects, indicating that light attenuation poses a risk to photosynthetic marine sponges. Examining benthic light levels over temporal scales would enable dredging proponents to be aware of conditions that could impact on sponge physiology.

Linking Southwest U.S. Drought to the Hiatus in Global Warming

NASA Astrophysics Data System (ADS)

Hoerling, M. P.; Quan, X. W.; Livneh, B.

2014-12-01

Weather and climate of the new millennium has been unkind to the Southwest United States. Precipitation has been deficient, especially compared to prior decades of the late 20thCentury. Temperatures have been consistently above historical averages. And drought conditions have prevailed for a period now stretching 15 years in duration. Impacts of these dry and warm conditions have included compromised health of forests and ecosystems, more wildfires, reduced water resources most notably the declining elevations of Lake Mead and Powell and substantially diminished annual flows in the Colorado River. The question remains open concerning the extent to which this protracted drought episode is strongly a symptom of human induced climate change. While the prolonged drought, including its recent regional expression over California, has been unusually severe relative to droughts of the 20thCentury, some droughts in the paleoclimate record were more severe. To be sure, various studies have detected the consequences of warming temperatures on the hydrologic cycle over the greater western United States, but the drought's severity has principally resulted from deficient rains, the cause for which has yet to been determined. Here we present results from analysis of historical climate simulations to determine the factors contributing to a protracted reduction in Southwest regional precipitation. A parallel set of 2000 year-long equilibrium coupled ocean-atmosphere experiments, one subjected to late 19th Century radiative forcing and a second subjected to early 21st Century radiative forcing, is used to explore attributable impacts of long-term anthropogenic climate change. Historical atmospheric climate simulations are also used to address the effects of the specific observed evolution of sea surface temperatures. These are characterized by appreciable natural variations, one feature of which has been a cooling in the tropical east Pacific during the last 15 years related to the

Responses of macroinvertebrates and local environment to short-term commercial sand dredging practices in a flood-plain lake.

PubMed

Meng, Xingliang; Jiang, Xiaoming; Li, Zhengfei; Wang, Jun; Cooper, Keith M; Xie, Zhicai

2018-08-01

In parts of the developing world, the expansion of industrial sand mining activities has led to serious environmental concerns. However, current understanding of the effects of this activity on an inland water ecosystem remains limited. Herein, we choose the "most affected" lake in China (Dongting Lake), to assess short-term (1year) effects of sand dredging on key environmental parameters and on the structure of the macroinvertebrate assemblage. Within the dredged area we observed increases in water depth (on average 2.17m), turbidity and changes in sediment composition (e.g., increase in % medium sand, and a decrease in % clay). In addition, dredging was associated with a 50 % reduction in taxa richness, Simpson and Shannon-Wiener indices, and a 72 and 99 % reduction in abundance and biomass, respectively. Indirect effects were also observed in the zone surrounding the extraction sites (ca. 500m), most likely as a result of the dredging processes (e.g., sediment screening and overspill) and water flow. No such effects were observed at a nearby reference site. The direct removal of sediment and indirect alteration of physical conditions (e.g., water depth, turbidity and sediment composition) appear to be the most likely cause of variations in the benthic community. Implications of our findings for the planning, management and monitoring of sand dredging in inland waters are discussed. Copyright © 2018 Elsevier B.V. All rights reserved.

Assessment of Mud-Capped Dredge Pit Evolution Offshore Louisiana: Implications to Sand Excavation and Coastal Restoration

NASA Astrophysics Data System (ADS)

Xu, K.; Miner, M. D.; Bentley, S. J.; Li, C.; Obelcz, J.; O'Connor, M. C.

2016-02-01

The shelf offshore Louisiana is characterized by a dominantly muddy seafloor with a paucity of restoration-quality sand proximal to shore. Discrete sand deposits associated with ancient rivers that incised the shelf during lower sea-level positions occur close to shore. These shelf channel sands have been targeted for coastal restoration projects resulting in significant cost savings over more distal deposits. Several recent projects targeted shelf paleo-fluvial deposits comprising relatively deep (10 m) channel sands underlying a muddy overburden. Because of contrasting characteristics of cohesive mud vs. non-cohesive sand and potential modern fluvial mud supply from the Mississippi and Atchafalaya Rivers, long term pit evolution is poorly understood relative to their more common sand-only counterparts. Alterations to seafloor topography from dredging shelf sediment resources can potentially affect oil and gas infrastructure or other resources of concern (i.e. historic shipwrecks) located proximal to dredge pits. Site-specific data required to make accurate predictions and empirical measurements to test and validate predictive models were only available for Peveto Channel offshore Holly Beach, Louisiana. Here we present new geophysical and geological data (bathymetry, sidescan, subbottom, and radionuclide of sediment cores) and physical oceanographic observations (hydrodynamics and sediment dynamics) collected at Raccoon Island (dredged in 2013) dredge pit in Louisiana. These field data collections along with pre-existing data provide a time-series to capture evolution at Raccoon Island post-excavation. Conceptual morphological models will be developed for dredge pit evolution and testing effectiveness of setback buffers protecting pipelines, habitats, and cultural resources. Our results will increase decision making ability regarding safety and protecting environmental and cultural resources, and better management of valuable sand resources.

Ecological Evaluation of Proposed Discharge of Dredged Material into Ocean Waters.

DTIC Science & Technology

1977-07-01

Methyl mercury Ref. 6 Oil and grease p. 229 - 5 5 Step 7.3 Petroleum hydrocarbons p. 226 Step 6.3 Phenol p. 241 Method SlO Method )I 78 p. 514 p. 4...and its compounds c. Cadmium and its compounds d. Petroleum hydrocarbons e. Known or suspected carcinogens, mutagens, or teratogens. 6 (This is a...its compounds 12 Cadmium and its compounds 12 6 0 Petroleum hydrocarbons : Aliphat ic 13 Aromatic 13 G8 0 0 * 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Table

Critical Metals In Western Arctic Ocean Ferromanganese Mineral Deposits

NASA Astrophysics Data System (ADS)

Hein, J. R.; Spinardi, F.; Conrad, T. A.; Conrad, J. E.; Genetti, J.

2013-12-01

Little exploration for minerals has occurred in the Arctic Ocean due to ice cover and the remote location. Small deposits of seafloor massive sulfides that are rich in copper and zinc occur on Gakkel Ridge, which extends from Greenland to the Laptev Sea, and on Kolbeinsey and Mohns ridges, both located between Greenland and mainland Europe. However, rocks were recently collected by dredge along the western margin of the Canada Basin as part of the U.S. Extended Continental Shelf (ECS) program north of Alaska. Sample sites include steep escarpments on the Chukchi Borderland, a newly discovered seamount informally named Healy seamount, the southern part of Alpha-Mendeleev Ridge, and several basement outcrops in Nautilus Basin. These dredge hauls yielded three types of metal-rich mineralized deposits: ferromanganese crusts, ferromanganese nodules, and hydrothermal iron and manganese deposits. Chemical analyses of 43 crust and nodule samples show high contents of many critical metals needed for high-technology, green-technology, and energy and military applications, including cobalt (to 0.3 wt.%), vanadium (to 0.12 wt.%), zirconium (to 459 grams/tonne=ppm), molybdenum (to 453 g/t), the rare-earth elements (including scandium and yttrium; yttrium to 229 g/t), lithium (to 205 g/t), tungsten (to 64 g/t), and gallium (to 26 g/t). The metal contents of these Arctic Ocean crusts and nodules are comparable to those found throughout the global ocean, however, these Arctic Ocean samples are the first that have been found to be enriched in rare metal scandium. The metal contents of these samples indicate a diagenetic component. Crusts typically form by precipitation of metal oxides solely from seawater (hydrogenetic) onto rock surfaces producing a pavement, whereas nodules form by accretion of metal oxides, from both seawater and pore waters (diagenetic), around a nucleus on the surface of soft sediment. The best evidence for this diagenetic input to the crusts is that crusts

A cool Southwest Indian Ocean connection to El Niño events

NASA Astrophysics Data System (ADS)

Wieners, Claudia; Manola, Iris; Ridderinkhof, Wim; Dijkstra, Henk; von der Heydt, Anna; Kirtman, Benjamin; Selten, Frank; de Ruijter, Wilhelmus

2014-05-01

Recent studies have shown that anomalously high sea surface temperatures (SST) in the southeastern equatorial Indian Ocean (IO) can influence early El Niño development by modulating the winds over the western Pacific. We have collected observational evidence for a dynamic connection between relatively cool SST developments in the southwestern Indian Ocean and the following years' El Niño. These cool anomalies appear over the so-called Seychelles thermocline Dome. Depending on strength and timing they generate a fast atmospheric response by stimulating an Indo-Pacific atmospheric bridge that leads to enhanced convection over the western Pacific. The slow oceanic response involves a pathway of upwelling Rossby and Kelvin waves that propagate towards and across the equator. We will present the first results of a series of dedicated climate model experiments. They were designed to stimulate the response of the coupled system to the SST cooling using a global climate model. First results seem to support the observational analysis.

Fifteen-year study of environmental dredging effect on variation of nitrogen and phosphorus exchange across the sediment-water interface of an urban lake.

PubMed

Liu, Cheng; Zhong, Jicheng; Wang, Jianjun; Zhang, Lu; Fan, Chengxin

2016-12-01

Environmental dredging has been applied widely in Chinese lakes to reduce their internal nutrient loads. However, the efficacy of dredging to reduce internal loading of nitrogen (N) and phosphorus (P) and to improve water quality has been questioned by some researchers. In this study, the long-term (∼15 years) effects of dredging to reduce internal N and P loading in a closed, polluted urban lake were investigated. The results showed that the release of soluble reactive phosphorus (SRP) could be suppressed quickly after dredging, and that the dredging effect was sustained for about 18 months. A significant release of NH 4 + -N was discovered during the first 2-8 months after dredging, followed by maintenance of low-level release rates for about 21-32 months. The continuous inflowing of external pollution loading led to the increase in the release rates of SRP and NH 4 + -N. The external pollution loading was therefore reduced three years after dredging to strengthen the remediation effect. After that, high diffusive flux from the sediment was observed for both NH 4 + -N and SRP during summer seasons for about six years, followed by a decreasing trend. The NH 4 + -N concentration in the overlying water was reduced after the reduction of external loading, while a high concentration of SRP in the overlying water was still observed during summer seasons. In conclusion, the mid-term (<3 years) reduction of internal N and P loading could be achieved by dredging if the external pollution loading were not reduced. Achieving long-term control would require modification of external loading. Copyright © 2016 Elsevier Ltd. All rights reserved.

[Effect of suspended silt from dredging at Yangtze estuary on Brachionus plicatilis].

PubMed

Wang, Jinqui; Xu, Zhaoli; Shi, Chun; Chen, Yaqu

2002-07-01

The effect of suspended silt from dredging at Yangtze estuary on Brachionus plicatilis was investigated by clonal culture (to construct life table) and population accumulative culture. The intrinsic increasing rate of the rotifer population was greatly reduced under different concentrations (1, 3, 5, 7 and 9 mg.ml-1) of silt, from 29.6% to 64.1%, and to a maximum of 130.0%. The suspended silt affected population survival rate, rather than its reproduction rate. In accumulative culture, the densities of female, males, parthenogenetic eggs, and resting eggs in the population were not affected by silt. It was concluded that the presence of suspended silt should have a certain negative influence on the rotifer population in dredging Yangtze estuary.

Untangling the History of Oceanic Peridotites Using Spinel Oxybarometry

NASA Astrophysics Data System (ADS)

Birner, S.; Warren, J. M.; Cottrell, E.; Davis, F. A.

2014-12-01

Comprehensive knowledge of the oxygen fugacity of the upper mantle is critical to understanding the processes associated with melt production, interaction, and extraction. Thus, it is important to understand how fO2 changes during a peridotite's thermal and petrologic history in the asthenospheric and lithospheric mantle, as metamorphic subsolidus reequilibration can result in changes to recorded fO2. A case study of Tongan forearc peridotites highlights the heterogeneity seen in mantle peridotites. We analyzed two dredges located 250 km apart along the trench: one dredge ranges in fO2 from 0.5 to 1 log unit above the QFM buffer, similar to analyses of supra-subduction zone xenoliths (e.g. Brandon and Draper, 1996; Wood and Virgo, 1989) while the other dredge ranges from QFM-0.75 to QFM+0.25 and exhibits high spinel Cr# (ranging from 0.45 to 0.75). Systematics between fO2, Ti concentration, olivine forsterite content, and Cr# within each dredge allow us to differentiate between the effects of melt extraction, melt interaction, and cooling. Because the spinel oxybarometry equation is dependent on temperature, it is important to be able to accurately determine the temperature recorded by peridotites. Though many geothermometers are available for mantle rocks, we assert that geothermometers based on Fe-Mg exchange between olivine and spinel are the most applicable to fO2 calculations, because the oxygen fugacity recorded by a mantle assemblage is primarily controlled by this exchange. Additionally, preliminary analyses of diffusion profiles across olivine-spinel grain boundaries provide insight into the cooling of peridotite in the oceanic lithosphere and its effects on oxygen fugacity. Mg-Fe exchange between olivine and spinel is controlled by the distribution coefficient, KD, which is dependent on both temperature and the proportion of Cr to other trivalent cations in spinel. We see an increase in olivine forsterite content towards the olivine-spinel interface

DESIGN AND IMPLEMENTATION OF EFFECTIVE MONITORING PROGRAMS FOR DREDGING CONTAMINATED SEDIMENT

EPA Science Inventory

Currently, there is a growing national debate about dredging contaminated sediments, including risks to human health and the environment as well as the overall effectiveness of remedial activities. Presently, monitoring methods are available to address both concerns. This present...

Discordant Temporal Turnovers of Sediment Bacterial and Eukaryotic Communities in Response to Dredging: Nonresilience and Functional Changes.

PubMed

Zhang, Na; Xiao, Xian; Pei, Meng; Liu, Xiang; Liang, Yuting

2017-01-01

To study the stability and succession of sediment microbial and macrobenthic communities in response to anthropogenic disturbance, a time-series sampling was conducted before, during, and 1 year after dredging in the Guan River in Changzhou, China, which was performed with cutter suction dredgers from 10 April to 20 May 2014. The microbial communities were analyzed by sequencing bacterial 16S rRNA and eukaryotic 18S rRNA gene amplicons with Illumina MiSeq, and the macrobenthic community was identified using a morphological approach simultaneously. The results indicated that dredging disturbance significantly altered the composition and structures of sediment communities. The succession rates of communities were estimated by comparing the slopes of time-decay relationships. The temporal turnover of microeukaryotes (w = 0.3251, P < 0.001 [where w is a measure of the rate of log(species turnover) across log(time)]) was the highest, followed by that of bacteria (w = 0.2450, P < 0.001), and then macrobenthos (w = 0.1273, P < 0.001). During dredging, the alpha diversities of both bacterial and microeukaryotic communities were more resistant, but their beta diversities were less resistant than that of macrobenthos. After recovery for 1 year, all three sediment communities were not resilient and had reached an alternative state. The alterations in sediment community structure and stability resulted in functional changes in nitrogen and carbon cycling in sediments. Sediment pH, dissolved oxygen, redox potential, and temperature were the most important factors influencing the stability of sediment communities and ecosystem multifunctionality. This study suggests that discordant temporal turnovers and nonresilience of sediment communities under dredging resulted in functional changes, which are important for predicting sediment ecosystem functions under anthropogenic disturbances. Understanding the temporal turnover and stability of biotic communities is crucial for

Discordant Temporal Turnovers of Sediment Bacterial and Eukaryotic Communities in Response to Dredging: Nonresilience and Functional Changes

PubMed Central

Zhang, Na; Xiao, Xian; Pei, Meng; Liu, Xiang

2016-01-01

ABSTRACT To study the stability and succession of sediment microbial and macrobenthic communities in response to anthropogenic disturbance, a time-series sampling was conducted before, during, and 1 year after dredging in the Guan River in Changzhou, China, which was performed with cutter suction dredgers from 10 April to 20 May 2014. The microbial communities were analyzed by sequencing bacterial 16S rRNA and eukaryotic 18S rRNA gene amplicons with Illumina MiSeq, and the macrobenthic community was identified using a morphological approach simultaneously. The results indicated that dredging disturbance significantly altered the composition and structures of sediment communities. The succession rates of communities were estimated by comparing the slopes of time-decay relationships. The temporal turnover of microeukaryotes (w = 0.3251, P < 0.001 [where w is a measure of the rate of log(species turnover) across log(time)]) was the highest, followed by that of bacteria (w = 0.2450, P < 0.001), and then macrobenthos (w = 0.1273, P < 0.001). During dredging, the alpha diversities of both bacterial and microeukaryotic communities were more resistant, but their beta diversities were less resistant than that of macrobenthos. After recovery for 1 year, all three sediment communities were not resilient and had reached an alternative state. The alterations in sediment community structure and stability resulted in functional changes in nitrogen and carbon cycling in sediments. Sediment pH, dissolved oxygen, redox potential, and temperature were the most important factors influencing the stability of sediment communities and ecosystem multifunctionality. This study suggests that discordant temporal turnovers and nonresilience of sediment communities under dredging resulted in functional changes, which are important for predicting sediment ecosystem functions under anthropogenic disturbances. IMPORTANCE Understanding the temporal turnover and stability of biotic communities is

Tectonic interpretation of the Andrew Bain transform fault: Southwest Indian Ocean

NASA Astrophysics Data System (ADS)

Sclater, John G.; Grindlay, Nancy R.; Madsen, John A.; Rommevaux-Jestin, Celine

2005-09-01

Between 25°E and 35°E, a suite of four transform faults, Du Toit, Andrew Bain, Marion, and Prince Edward, offsets the Southwest Indian Ridge (SWIR) left laterally 1230 km. The Andrew Bain, the largest, has a length of 750 km and a maximum transform domain width of 120 km. We show that, currently, the Nubia/Somalia plate boundary intersects the SWIR east of the Prince Edward, placing the Andrew Bain on the Nubia/Antarctica plate boundary. However, the overall trend of its transform domain lies 10° clockwise of the predicted direction of motion for this boundary. We use four transform-parallel multibeam and magnetic anomaly profiles, together with relocated earthquakes and focal mechanism solutions, to characterize the morphology and tectonics of the Andrew Bain. Starting at the southwestern ridge-transform intersection, the relocated epicenters follow a 450-km-long, 20-km-wide, 6-km-deep western valley. They cross the transform domain within a series of deep overlapping basins bounded by steep inward dipping arcuate scarps. Eight strike-slip and three dip-slip focal mechanism solutions lie within these basins. The earthquakes can be traced to the northeastern ridge-transform intersection via a straight, 100-km-long, 10-km-wide, 4.5-km-deep eastern valley. A striking set of seismically inactive NE-SW trending en echelon ridges and valleys, lying to the south of the overlapping basins, dominates the eastern central section of the transform domain. We interpret the deep overlapping basins as two pull-apart features connected by a strike-slip basin that have created a relay zone similar to those observed on continental transforms. This transform relay zone connects three closely spaced overlapping transform faults in the southwest to a single transform fault in the northeast. The existence of the transform relay zone accounts for the difference between the observed and predicted trend of the Andrew Bain transform domain. We speculate that between 20 and 3.2 Ma, an

Controlling toxic cyanobacteria: effects of dredging and phosphorus-binding clay on cyanobacteria and microcystins.

PubMed

Lürling, Miquel; Faassen, Elisabeth J

2012-04-01

Sediment dredging and Phoslock(®) addition were applied individually and in combination in an enclosure experiment in a Dutch hypertrophic urban pond. These measures were applied to control eutrophication and reduce the risk of exposure to cyanobacterial toxins. Over the 58 days course of the experiment, cyanobacteria (predominantly Microcystis aeruginosa) gradually decreased until they dropped below the level of detection in the combined treated enclosures, they were reduced in dredged enclosures, but remained flourishing in controls and Phoslock(®) treated enclosures. Cyanobacteria were, however, less abundant in the enclosures (medians chlorophyll-a 30-87 μg l(-1)) than in the pond (median chlorophyll-a 162 μg l(-1)), where also a thick surface scum covered one-third of the pond for many weeks. Soluble reactive phosphorus (SRP), total phosphorus and total nitrogen concentrations were significantly lower in the combined dredged and Phoslock(®) treated enclosures than in controls. Median SRP concentrations were 24 μg P l(-1) in the combined treatment, 58 μg P l(-1) in dredged enclosures, and 90 μg P l(-1) in controls and 95 μg P l(-1) in Phoslock(®) treated enclosures. Hence, the combined treatment was most effective in decreasing SRP and TP, and in lowering cyanobacterial biomass. Microcystin (MC) concentrations were analyzed by LC-MS/MS. MC concentrations and cyanobacterial biomass were positively correlated in all treatments. Mean MC concentrations in controls (71 μg l(-1)), Phoslock(®) treated enclosures (37 μg l(-1)) and dredged enclosures (25 μg l(-1)) exceeded the provisional guideline of 20 μg l(-1), whereas mean MC concentrations were 13 μg l(-1) in the combined treated enclosures. All samples contained the MC variants dmMC-RR, MC-RR, MC-YR, dmMC-LR and MC-LR; traces of MC-LY and nodularin were detected in few samples. The different treatments did not change the relative contribution of the variants to the MC pool; MC profiles in all

A new species of Trimma (Pisces; Gobiidae) from the South-West Islands of Palau, western Pacific Ocean.

PubMed

Winterbottom, Richard

2018-01-09

A new species of Trimma is described from South-West Islands of Palau. Trimma hamartium n. sp. lacks scales on the cheeks and opercle, has 8-9 scales in the predorsal midline, 17-19 pectoral-fin rays with 5-10 branched rays in the middle of the fin, an unbranched 5th pelvic-fin ray that is 51-64% the length of the 4th ray, 17-19 gill rakers on the outer surface of the first gill arch, an U-shaped interorbital trench with a narrow, slit-like postorbital trench ending at the last papilla in row p, and has 6 papillae in row c beneath the eye. When freshly collected, the species is very similar in appearance to T. preclarum, with which it is syntopic at three of the more northern islands of the South-West Islands.

Specific features of basalts from the western part of Andrew Bain Fault, Southwest Indian Ridge

NASA Astrophysics Data System (ADS)

Peyve, A. A.; Skolotnev, S. G.

2017-12-01

This paper reports original data on the composition of volcanic rocks in the western part of the Andrew Bain Fault of the South-West Indian Ridge obtained in the 23rd voyage of R/V Akademik Nikolai Strakhov. In accordance with high La/Th and low Nb/U ratios, the basalt compositions of stations S2317, S2318, and S2330 could result from melting of the DM-type source with HIMU traces. Meanwhile, the enriched samples of station S2326 correspond to a mantle source with a considerable contribution of recycled sediments (EM). Sample S2326/35, which is composed of a melt almost completely depleted in EM material, corresponds to the volcanic rocks of the Marion and Prince Edward islands. The obtained and available data on the SWIR segment from Bouvet Island to Andrew Bain Fault are indicative of small mantle heterogeneities in this region. Two possible variants of their origin are considered: either preservation of the enriched material fragments in the depleted mantle during the split of Gondwana or "contamination" of the mantle with plume material with the formation of vein irregularities before opening of the ocean in this region. In the latter case, the plume material could cover a huge area not constrained by the young plume magmatism regions on Bouvet, Marion, and Prince Edward islands.

Simulations of dredged sediment spreading on a Posidonia oceanica meadow off the Ligurian coast, Northwestern Mediterranean.

PubMed

Capello, M; Cutroneo, L; Ferranti, M P; Budillon, G; Bertolotto, R M; Ciappa, A; Cotroneo, Y; Castellano, M; Povero, P; Tucci, S

2014-02-15

The sandy deposits from dredging can have negative effects on the environment such as increase in suspended solids in the water column and their consequent transport. An experimental study was conducted to characterize water masses, dynamics, and sedimentation rates on the Ligurian continental shelf (Italy), where both a sand deposit, that could be used for beach nourishment, and a nearby Posidonia oceanica meadow coexist. The environmental plan provides a mathematical simulation of the sediment-dispersion to evaluate the possible impact on the meadow. It has been calculated that the dredging could double the concentration of suspended particles, but its scheduling will preclude a sediment accumulation. All the information obtained from this work will be used to study the environmental feasibility of the sand deposit exploitation and as starting point for drawing up the monitoring plan in case of dredging. Copyright © 2013 Elsevier Ltd. All rights reserved.

40 CFR 225.3 - Procedure for invoking economic impact.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Procedure for invoking economic impact. 225.3 Section 225.3 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CORPS OF ENGINEERS DREDGED MATERIAL PERMITS § 225.3 Procedure for invoking economic impact. (a...

40 CFR 225.3 - Procedure for invoking economic impact.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 25 2011-07-01 2011-07-01 false Procedure for invoking economic impact. 225.3 Section 225.3 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CORPS OF ENGINEERS DREDGED MATERIAL PERMITS § 225.3 Procedure for invoking economic impact. (a...

40 CFR 225.3 - Procedure for invoking economic impact.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 26 2013-07-01 2013-07-01 false Procedure for invoking economic impact. 225.3 Section 225.3 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CORPS OF ENGINEERS DREDGED MATERIAL PERMITS § 225.3 Procedure for invoking economic impact. (a...

40 CFR 225.3 - Procedure for invoking economic impact.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 25 2014-07-01 2014-07-01 false Procedure for invoking economic impact. 225.3 Section 225.3 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CORPS OF ENGINEERS DREDGED MATERIAL PERMITS § 225.3 Procedure for invoking economic impact. (a...

40 CFR 225.3 - Procedure for invoking economic impact.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 26 2012-07-01 2011-07-01 true Procedure for invoking economic impact. 225.3 Section 225.3 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CORPS OF ENGINEERS DREDGED MATERIAL PERMITS § 225.3 Procedure for invoking economic impact. (a...

40 CFR 230.43 - Vegetated shallows.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 25 2014-07-01 2014-07-01 false Vegetated shallows. 230.43 Section 230.43 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING SECTION 404(b)(1) GUIDELINES FOR SPECIFICATION OF DISPOSAL SITES FOR DREDGED OR FILL MATERIAL Potential Impacts on...

40 CFR 230.43 - Vegetated shallows.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 26 2013-07-01 2013-07-01 false Vegetated shallows. 230.43 Section 230.43 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING SECTION 404(b)(1) GUIDELINES FOR SPECIFICATION OF DISPOSAL SITES FOR DREDGED OR FILL MATERIAL Potential Impacts on...