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1.
Shipping activities in the Port of New York-New Jersey are currently threatened by restrictions on dredging of navigational channels and private berthing areas becaused of concerns about the environmental effects caused by ocean disposal of the dredged material. Current proposals for solutions to the problem include ocean disposal of uncontaminated material, use of confined disposal facilities (both upland facilities and containment islands), subaqueous barrow pits, and processing and treatment for contaminated materials. A project to produce a complete “treatment train” for processing and decontaminating dredged material is described. The work is divided into several phases: treatability studies of commercial and nonproprietary technologies at volumes of 19 liters (bench scale) and up to 19 m3 (pilot scale); specification of a treatment train; and implementation of a large-scale facility that can process 76,000–382,000 m3 of dredged material per year. The goal is to achieve operational status for the facility by the end of 1999. 相似文献
2.
John F. Tavolaro 《Environmental Geology》1984,6(3):133-140
The purpose of this study was to quantify the dry mass of dredged material involved in each stage of typical clamshell dredging
and ocean disposal activities in order to identify and quantify “losses” of dredged material Turbidity plumes generated at
dredging sites were also observed Approximately 2% of the dredged material was lost at the dredging site Of this quantity
61% was due to the dredging itself and 38% was due to intentional barge overflow Approximately 3 7% of the dredged material
was lost at the Mud Dump Site during disposal Total loss of dredged material during these clamshell dredging and ocean disposal
operations was calculated to be 5 6% Observations revealed that turbidity plumes were local features which traveled along
the bottom for several hundred feet These plumes only persisted while dredging was occuring, and ambient conditions were established
within a relatively short time after dredging ceased 相似文献
3.
Omran Frihy Wahid Moufaddal Essam Deabes Essam El Din Helmy 《Arabian Journal of Geosciences》2016,9(14):637
The present study is the first attempt in Egypt to assess feasibility of using of dredging material from Damietta Harbor in the northwestern Nile Delta for erosion control. The study also provides an economic evaluation for the shoreline management alternatives selected to mitigate for the effects of coastal erosion at two pilot eroding areas (namely, A and B) located near the Damietta Harbor. Results of compatibility analysis reveal that the dredging material is fairly compatible with the native sand of the nearby eroding beaches. In addition to soft nourishment by dredged sand, other types of coastal engineering measures which are often used in erosion management area were also evaluated as alternatives for erosion control and mitigation solution. Economic feasibility assessment by means of cost-benefit analysis of direct and indirect items has been carried out to facilitate comparison between these alternatives. Analysis of alternatives has been also supported by other criteria to select the cost-effective and environmentally acceptable option to protect the eroding pilot areas. These criteria include the high total cost paid for maintenance of the Damietta Harbor channel with no use, anticipated impacts on the littoral system, sustainability, future plans for protection of the existing coastlines, and lessons learned from previous shore protection works in the Nile Delta. The final selection of the best viable alternative indicates that the procedure of beach nourishment is the most appropriate form for protection area A, while a combination of groins and sand nourishment is more relevant for area B. In any case, material dredged from the navigation approach of the Damietta Harbor should be utilized as a borrow material in the nourishment schemes and excluding use of the terrestrial sources. 相似文献
4.
Nesting colonial waterbirds along the Atlantic Coast of the United States face a number of landscape-level threats including human disturbance, mammalian predator expansion, and habitat alteration. There have been changes from 1977 to the mid-1990s in use of nesting habitats and populations of a number of seabird species of concern in the region, including black skimmersRynchops niger Linnaeaus, common ternsSterna hirundo Linnaeaus, gull-billed ternsSterna nilotica Linnaeaus, least ternsSterna antillarum Lesson, royal ternsSterna maxima Boddaert, and sandwich ternsSterna sandvicensis Cabot. These species form colonies primarily on the following habitat types: large, sandy barrier or shoal islands, natural estuarine or bay islands (mostly marsh) man-made islands of dredged deposition materials (from navigation channels), and the mainland. Significant changes in the use of the dredged material islands have occurred for these species in New Jersey and North Carolina, but not in Virginia. Population declines and changes in bird habitat use appear to be at least partially associated with the conditions and management of the existing dredged material islands, coastal policy changes associated with creating new dredged material islands, and competing demands for sand for beach augmentation by coastal communities. As these and other coastal habitats become less suitable for colonial waterbirds, other man-made sites, such as, bridges and buildings have become increasingly more important. In regions with intense recreational demands, coastal wildlife managers need to take a more aggressive role in managing natural and man-made habitats areas and as stakeholders in the decision-making process involving dredged materials and beach sand allocation. 相似文献
5.
We examined the effects of dredged material disposal on benthic macroinvertebrates in Galveston Bay, Texas, USA, while investigating the utility of estimating secondary production with estimation methods that have less rigorous data requirements than most classical techniques. Production estimates were compared to estimates of benthic consumption by blue crabs, shrimp, and epibenthic fish. There was no evidence that dredged material disposal had a detrimental impact on benthic production; however, production was low throughout the entire bay the year following dredged material disposal, which may have obscured an assessment of the impact of disposal. In fact, disposal sites yielded both the highest production estimates and species richness in both the upper and lower bay areas 2 yr after disposal. Of the five estimation methods used, two that incorporated environmental parameters (temperature and depth) yielded similar and moderate results, ranging from 1.1 g ash-free dry weight m2 yr1 to 26.9 g ash-free dry weight (AFDW) m?2 yr?1 over the 4 yr studied. Daily food ration estimates applied to fishery-independent trawl-survey data yielded overall benthic consumption estimates ranging from 1.1 g AFDW m?2 to 1.7 g AFDW m?2. A second method of estimating consumption, which used transfer efficiency estimates and annual fisheries statistics produced slightly lower benthic consumption estimates (0.72–1.13 g AFDW m?2). The average consumption estimate exceeded benthic production in the upper bay in one of the 4 yr for which benthic production was estimated. In years with high benthic production, the estimated benthic food requirement of epibenthic predators was roughly 10–15% of benthic production. Variation in annual benthic production estimates was two to three times greater than the variation in consumption estimates. 相似文献
6.
A dredged material disposal operation was monitored at a location in Lake Erie, 8 km offshore at Ashtabula, Ohio, in 1975.
Approximately 200 sediment cores were collected from 12 experimental and 4 control locations before and after dredging and
analyzed for the grain-size distribution and related heavy-metal content.
The dredged sediments were similar to those from the lake bottom at the disposal and control sites. Because of this similarity,
it was extremely difficult to distinguish between the dredged material and the lake bottom sediments without tagging the material
with dyes or radioactive isotopes. A sequence consisting of a linear discriminant analysis followed by a univariate and multivariate
analysis of variance was successfully applied to discriminate between the dredged and the original lake sediments. Results
indicate that 4 months after the disposal operation some stations had returned to predisposal conditions, a probable result
of currents stripping dredged material off the lake bottom. The analysis of variance indicated that the clay-size fraction
was responsible for initial changes in the grain-size distribution. Storm induced scouring caused an eventual return of the
grain-size distribution to predisposal conditions.
In support of this observation, the concentrations of iron and zinc, which were statistically correlated to the clay size
fraction, also exhibited the same trends. 相似文献
7.
8.
Cluster analysis of some chemical characteristics of marine sediments and associated waste deposits in the New York Bight
reveals the existence of four cluster facies. Cluster facies I is the sediment containing dredged wastes from New York Harbor.
Cluster facies II is the widespread sand and gravel deposit of the continental shelf. Cluster facies III is the finergrained
material in the Hudson Channel and the material accumulated in the sewage sludge disposal area. Cluster facies IV is not easily
identified; it may correspond to some relict sedimentary feature in the area.
Editor's Note: Ali is now with the Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole,
Massachusetts 02543; Gross is now with Chesapeake Bay Institute. The Johns Hopkins University, Baltimore, Maryland 21218. 相似文献
9.
A numerical model of fine-grained sediment dispersion in the New York Bight of the North American continental shelf is presented.
Large amounts of waste material have been dumped in this region and the dispersal patterns of this material are of great interest
to environmental managers. The model assumes that fine sediment resuspension is determined by surface wave activity and that
transport is determined by tidal currents. Considering surface wave activity to be a random process reduces sediment motion
to a random walk which is governed by a diffusion equation. The diffusion equation is solved numerically by an implicit time
difference, finite element algorithm for a number of initial conditions.
Initial conditions corresponding to ocean dumping sites show patterns of dispersal controlled by the geometry of the study
region and the anisotropy of the tides. Material dumped at currently used dump sites reaches sensitive coastal areas before
it leaves the continental shelf. Examination of the diffusion coefficients suggests an alternative dump site for fine-grained
material. This dump site is relatively near sources of dumped material but produces minimal impact on coastal areas. This
site should be considered as a possible alternative to expensive direct disposal at deep ocean sites. 相似文献
10.
吹填泥浆中土颗粒沉降-固结规律研究 总被引：1，自引：0，他引：1
吹填泥浆中土颗粒沉降-固结过程十分复杂,其中土颗粒的沉降固结规律并不明确。室内沉降试验采用一种改进的方法--分层抽取法,先得到土颗粒体积分布规律,再利用体积通量函数法计算不同粒组颗粒平均沉速。计算结果表明,吹填泥浆在沉降过程中会出现3个区域,分别是干涉沉降区、絮体压缩沉降区和自重固结区;在沉降初期0～1 h和1～7 h内,干涉沉降区内土颗粒沉速远小于Stokes公式沉速计算值,颗粒沉速分别与颗粒直径的0.488 1和0.111 7次方有关。絮体压缩沉降区和自重固结区内颗粒基本不出现分选现象,均属于泥浆颗粒的沉积物;该试验中絮体压缩沉降区的密度约为1.04 g/cm3。 相似文献
11.
C. C. von der Borch 《Australian Journal of Earth Sciences》2013,60(2):755-759
Phosphatic concretions and nodules, some of which are coated with goethite, have been dredged at depths between 210 and 385 m from the upper continental slope off northern New South Wales. Some of these appear to have been concentrated on a low sea level terrace at a depth of about 210 m by wave action, while deeper‐water non‐abraded examples may have been winnowed from host sediments by relatively gentle current activity. Similarities in structure, mineralogy and age of contained fauna are noted between nodules described in this paper and phosphatic nodules from the California Continental Borderland, the Chatham Rise off New Zealand and Cainozoic sediments outcropping in Victoria. It is proposed that the Eastern Australian material formed as phosphatic concretions within phosphorus‐enriched slope sediments during diagenesis and that they have since been winnowed, exposed and in some cases re‐cemented into agglomerations on the sea floor in areas of low sedimentation rate. 相似文献
12.
A variety of sediment types were identified in sediment cores taken at the dredged material dumpsite in the New York Bight.
Black sandy mud is characteristic of dumped dredged material while glauconitic and quartzose sands are typical of the naturally
deposited sediments underlying the deposit. The sedimentological investigation indicates that largescale differentiation of
dumped material occurs at the dumpsite. Laminated sediments and discrete beds are typical of the central part of the deposit,
the area that receives the bulk of direct dumping. Relatively homogeneous, fine-grained sediments, presumably derived from
the area of direct dumping, are characteristic of the material present at the periphery of the deposit. Preferential transport
of fine-grained material to the fringes of the deposit may be an important contaminant transport mechanism in the area. Incursion
of glauconitic sand, derived from surrounding areas, onto the edges of the deposit is also believed to occur. Based on bathymetric
surveys of the area conducted in 1936, 1973, and 1978, rates of dredged material accumulation at the dumpsite have been estimated
for the period 1936–1978. The calculated rates range from 50 cm/yr at the apex of the deposit to 6 cm/yr at the periphery.
Contribution 294 of the Marine Sciences Research Center (MSRC) of the State University of New York at Stony Brook. 相似文献
13.
围海造地工程对香港维多利亚港现代沉积作用的影响 总被引：17，自引：1，他引：16
对采自香港维多利亚港的 4个 6m长的沉积柱状样作了2 10 Pb及Pb、Zn、Cu含量分析。结果表明,维多利亚港开阔区域现代沉积速率在 0.3～ 2cm/a之间变化,西部大于东部。在九龙海峡主航道上,基本上处于冲淤平衡状态。由于近百年来围海造地、海岸工程建设,使维多利亚港的岸线发生了较大的变化,在台风避风塘等潮流作用较弱的区域及靠近城市排污口的地方沉积速率可达 3～ 5cm/a,这表明围海造地、海岸工程等造成的岸线变化是影响维多利亚港堆积侵蚀的主要因素。Pb、Zn、Cu等重金属在沉积柱状样中的分布表明,在沉积速率较快的区域,重金属的污染也较为严重。 相似文献
14.
Alex L. Croft Lynn A. Leonard Troy D. Alphin Lawrence B. Cahoon Martin H. Posey 《Estuaries and Coasts》2006,29(5):737-750
The objective of this study was to determine if the placement of dredged material on sediment-starved back barrier marshes
in southeastern North Carolina could offset submergence without negatively affecting function. Clean sediment was placed in
thickness from 0 to 10 cm, on deteriorated and non-deteriorated marsh plots. Original stem densities were greater, in non-deteriorated
plots (256 stems m−2) compared to deteriorated sites (149 stems m−2). By the second growing season (after sediment additions), stem densities in the deteriorated plots (308 stems m−2) approached levels in the non-deteriorated plots (336 stems m−2). Sediment additions to, both nos-deteriorated and deteriorated plots resulted in a higher redox potential with plots receiving
the most sediment exhibiting the highest Eh values. In deteriorated plots, placement of dredged material had the greatest effect on plant density, but also affected
soil oxidation-reduction potential and sediment deposition (or mobility). Following sediment placement, substrate texture
and composition incrementally returned to prefill conditions due to a combination of bioturbation and sedimentation. Where
infaunal differences occurred, they were generally less abundant in deteriorated plots, but responses to sediment addition
were variable. Sediment addition had little effect on the non-deteriorated plots, suggesting that the disposal of certain
types of dredged material in marshes may be useful to mitigate the effects of marsh degradation without adversely affecting
non-deteriorating marsh. 相似文献
15.
堆场疏浚淤泥含水率分布规律调查研究 总被引：1，自引：0，他引：1
堆场淤泥的沉积、固结过程直接影响到后续淤泥的处理方法和经济成本。通过在南水北调东线白马湖现场使用绞吸式挖泥船疏挖白马湖底泥,吹淤进入堆场,研究了堆场内淤泥含水率随时间、沿程和堆场深度上的变化规律。结果表明,堆场内疏浚淤泥含水率随时间逐渐降低,随沿程逐渐升高,130 d后吹淤口处含水率降低到20%～50%之间;160 d后,距离吹淤口100 m距离吹淤口200 m处和处含水率维持在100%～150%和100%～170%之间;随深度逐渐降低,到40 cm深时,含水率降低减缓,维持在140%左右;疏浚泥中黏粒含量随着距离吹淤口距离的增大而增多,随着深度的加深而减小,疏浚泥的渗透系数随着距离吹淤口距离的增大而减小,随深度的加深而增大。 相似文献
16.
疏浚污泥的处理与处置是世界性的环保难题,资源化处理技术的研究有重要的工程应用价值。通过化学处理技术,在疏浚污泥中加入磷酸,将其中的重金属转变成难溶的金属磷酸盐固化在处理产物中,加入FeCl3试剂与水作用,改善处理后污泥的物理力学性质;通过热处理技术大大降低有机物的含量,使固体残留物无害化。研究了不同磷酸含量和不同FeCl3含量对其物理力学和热学性质的影响。试验结果表明,处理后的疏浚污泥污染物活动性降低,并有可能用作建筑材料。 相似文献
17.
The Poplar Island Dredged Material Placement Site in Talbot County, Maryland is proposed to be used for the restoration of Poplar Island and for the creation of desirable habitats lost through erosion of Poplar Island by the beneficial use of clean and uncontaminated dredged material from the Chesapeake Bay approach channels to the Port of Baltimore. The Poplar Island baseline environmental assessment studies included among others, seasonal water quality, benthic community, and benthic tissue contaminants, that were carried out by the Maryland Department of the Environment, in cooperation with the University of Maryland, from September 1995 to July 1996. The purpose of the study was to document the present-day levels of nutrients, trace metals, and organic contaminants in the area to establish a baseline against which subsequent levels and biological responses may be compared. The overall results of the study indicate that Poplar Island and vicinity areas are non-impacted in terms of water quality and benthic tissue contamination. The nutrient levels in the water column were below average for this region of Chesapeake Bay, while the trace metals and organic contamination in the benthic tissues were comparable to other sites within Chesapeake Bay that are not impacted by direct inputs. Concentrations were equivalent or lower than those found at Hart-Miller Island, a disposal facility outside Baltimore Harbor, Maryland containing dredged material. 相似文献
18.
Water reservoirs, irrigation and sedimentation in Central Asia: a first-cut assessment for Uzbekistan 总被引：1，自引：1，他引：0
S. Rakhmatullaev F. Huneau H. Celle-Jeanton P. Le Coustumer M. Motelica-Heino M. Bakiev 《Environmental Earth Sciences》2013,68(4):985-998
Water reservoirs play an important role in areas with limited and erratic precipitation where water is stored and re-distributed later for different purposes. Irrigation is primarily a major water consumer in arid countries of Central Asia for the economic development, employment and food security of the region. The major rivers of Central Asia (e.g., Amu Darya, Syr Darya, and Zerafshan) are turbid watercourses. Sedimentation reduces the main reservoir asset i.e., its volume capacity. In addition, vast territories of the region’s countries have been transformed for agriculture to grow water intensive crops such as cotton, rice and wheat during the Soviet Union that dramatically accelerated soil erosion by water and wind. Thus, many man-made water reservoirs are affected by high sedimentation rates. Moreover, uneven spatial and temporal water resources and a Soviet-inherited unified hydraulic infrastructure have raised transboundary reservoir management issues over water resources allocation among the countries in the region such as Kyrgyzstan, Tajikistan, Kazakhstan, Uzbekistan and Turkmenistan. The rivers such as Syr Darya and Amu Darya are already regulated by more than 78 and 94 %, respectively and attempts for new reservoir projects upstream raises increased concerns of the downstream countries (e.g., the Rogun hydropower station in Tajikistan and the Toktogul reservoir in Kyrgyzstan). For instance, the uncoordinated use of reservoirs has caused the Arnasai lake problem in Uzbekistan with environmental, material damage and social unrest. The aim of this paper is first to review the present conditions and the role of man-made water reservoirs for irrigation in Central Asia with special focus on Uzbekistan, second to document past and current reservoir sedimentation conditions in Uzbekistan and third to discuss research carried out by Soviet and present-time local research community in the domain of erosion and sedimentation in the region. 相似文献
19.
排海污水中往往含有一定数量的悬浮物, 这些悬浮物在排放口附近中呈现出复杂的扩散与沉降特性, 具有挟沙射流的典型运动特征。本文系统回顾了静水、恒定流、潮流和波浪等环境下排海污水挟沙射流的研究进展, 发现在不同动力环境下挟沙射流泥沙沉积形态存在显著差异性。如何精细刻画波浪-水流-射流多动力耦合过程及其对泥沙输运和沉降过程的影响是排海污水挟沙射流研究的难点所在, 对此提出了基于PIV/PLIF固相分离物理试验、粒子追踪两相流数值模型和拉格朗日积分模型, 系统开展波流共同作用下挟沙射流运动规律研究的设想, 以期为排海污水工程的优化设计提供重要参考。 相似文献
20.
含水率对重塑淤泥不排水强度性质的影响 总被引：2，自引：0，他引：2
通过室内调配不同含水率的重塑淤泥,利用研制的室内微型高精度十字板剪切仪,研究了含水率对重塑淤泥重塑不排水强度的影响。该仪器的剪切强度分辨率为1 Pa,经试验验证,仪器测量结果的稳定性较好,但对强度越低的重塑淤泥试样其测量值的相对平均偏差越大。淤泥含水率对淤泥的不排水强度有显著影响,不排水强度均随含水率/液限的增大而减小,含水率/液限越大,不排水强度下降趋势越小。相同的含水率/液限时,不同种类的重塑淤泥的不排水强度比较接近。在双对数坐标中,不排水强度均随含水率/液限的增大而线性减小。由试验数据得出了不同种类重塑淤泥的不排水强度与含水率/液限之间的关系式,利用该关系式可以求得每一种重塑淤泥任意含水率下的不排水强度。文中的试验值大于洪振舜提出的关系式的计算值。当IL >2时,试验值与Locat和Leroueil提出的关系式的计算值基本吻合,当IL <2时,试验值大于Locat和Leroueil提出的关系式的计算值。 相似文献